var Str_DB=new Array

Str_DB[0]=new Array
Str_DB[0][0]="./Page/Model/NCKU/A01.Htm"
Str_DB[0][1]="Model: NCKU-A01 Screw Pair Model"
Str_DB[0][2]="Group: Lower Pairs Description: A Screw Pair Allows Only A Screw Motion, Which Consists A Rotation Combined With A Translation That Is Parallel To The Rotation, \
Between Two Links. In Another Words, The Screw Motion Represents A Motion Combination Of A Rotation And A Translation In Which The Translation Is Related To\
 The Rotation. In Forms Of Screw Joints, The Screw Pair Is Commonly Appeared In The Effort-Saving Devices, Such As The Jacks And Cranes, Etc."




Str_DB[1]=new Array
Str_DB[1][0]="./Page/Model/NCKU/C01.Htm"
Str_DB[1][1]="Model: NCKU-C01 Scale "
Str_DB[1][2]="Group: Simple Kinematic Linkages Description: The Scale Is An Application Of The Parallel Four-Bar Linkages. Based On The Property Of Geometry Of Equal Link Length, The Two \
Pans Move With Parallel Pathes From Which The Function Of Measurement Can Be Achieved. "




Str_DB[2]=new Array
Str_DB[2][0]="./Page/Model/NCKU/D01.Htm"
Str_DB[2][1]="Model: NCKU-D01 Quick-Return Mechanism"
Str_DB[2][2]="Group: Slider-Crank Mechanisms  Description: Slider-Crank Mechanism Is A Four-Bar Mechanism With A Crank, A Connecting Rod, And A Slider In Which The Frame Forms One Element \
Of The Prismatic Pair. The Function Of The Slider-Crank Mechanisms Is To Make A Motion Transformation Between A Rotation And A Translation. Generally, The \
Input Power Is Exerted On The Crank And The Output Is The Slider. For Example, The Mechanical Press Is One Application Of The Slider-Crank Mechanisms. The \
Power Generated From Motor Is Inputted To The Crank, The Mold Is Attached To The Slider, And The Raw Materials Are Placed On The Frame. When The Crank Of \
The Press Is Rotating Continuously, The Slider Can Press The Raw Materials Reciprocally."




Str_DB[3]=new Array
Str_DB[3][0]="./Page/Model/NCKU/E01.Htm"
Str_DB[3][1]="Model: NCKU-E01 Disk Cam Mechanism With Roller Follower"
Str_DB[3][2]="Group: Cam Mechanisms  Description: This Cam Mechanism Comprises Of A Heart-Like Disk Cam, A Roller Follower, And A Frame. When The Cam Is Driven, The Follower \
Outputs A Reciprocating Linear Motion."




Str_DB[4]=new Array
Str_DB[4][0]="./Page/Model/NCKU/E02.Htm"
Str_DB[4][1]="Model: NCKU-E02 Multiple-Turn Cylindrical Cam Mechanism "
Str_DB[4][2]="Group: Cam Mechanisms  Description: This Is A Cylindrical Cam With Two Helical Grooves, Mating With The Follower With Elongated Shape. As The Cylindrical Cam Is \
Continuously Driven, The Follower Outputs A Reciprocating Translation. And, The Output Cycle Is Completed Through Seven Revolutions Of The Cylindrical Cam."




Str_DB[5]=new Array
Str_DB[5][0]="./Page/Model/NCKU/E03.Htm"
Str_DB[5][1]="Model: NCKU-E03 Positive Motion Cam Mechanism "
Str_DB[5][2]="Group: Cam Mechanisms  Description: For Disk Cam Mechanisms, The Motion Relationship Between Cam And Follower Is Not Completely Determined. It Needs Some Auxiliary \
Forces, E.G., The Gravity Force Or Spring Force, To Avoid The Separation Between Cam And Follower During Operation. Therefore, The Positive Motion Cam \
Mechanism Is The One Whose Cam Can Determinately Drive The Follower, I.E., Cam And Follower Keeps Contact During The Overall Operation, Without Using \
Auxiliary Forces. For The Shown Models, This Cam Mechanism Has A Disk Cam Whose Profile Is Formed By Three Equal-Radius Arcs. Based On This Special \
Geometry, Its Cam And Follower Can Keep Contact Over The Cycle Of Motion."




Str_DB[6]=new Array
Str_DB[6][0]="./Page/Model/NCKU/F01.Htm"
Str_DB[6][1]="Model: NCKU-F01 Spur Gear Mechanism"
Str_DB[6][2]="Group: Gear Mechanisms  Description: This Mechanism Demonstrates The Transmission Of A Spur Gear Pair. Spur Gear Is The Cylindrical Gear, Which Forms Teeth On A \
Cylindrical Surface, Having External Teeth. The Spur Gear Pair Transmits A Rotation Between Two Parallel Axes. The Transmission Efficiency Of A Spur Gear \
Pair Can Even Achieve 98 Percent."




Str_DB[7]=new Array
Str_DB[7][0]="./Page/Model/NCKU/F02.Htm"
Str_DB[7][1]="Model: NCKU-F02 Crossed Helical Gear Mechanism"
Str_DB[7][2]="Group: Gear Mechanisms  Description: This Mechanism Demonstrates The Transmission Of A Crossed Helical Gear Pair. The Crossed Helical Gear Pair Comprises Of Two \
Matching Helical Gears With Crossed Axes. It Can Transmit The Motion Between Two Crossed Axes."




Str_DB[8]=new Array
Str_DB[8][0]="./Page/Model/NCKU/F03.Htm"
Str_DB[8][1]="Model: NCKU-F03 Straight Bevel Gear Mechanism"
Str_DB[8][2]="Group: Gear Mechanisms  Description: This Mechanism Demonstrates The Transmission Of A Straight Bevel Gear Pair. The Straight Bevel Gear Is A Gear With Teeth Formed \
On A Conical Surface. The Transmission Of A Straight Bevel Gear Pair Is Equivalent To The Rolling Contact Between Two Semi-Cones. It Can Transmit The Motion\
 Between Two Intersecting Axes With Any Intersecting Angels. For Example, The Shown Mechanism Illustrates Two Mating Straight Bevel Gears With Orthogonal \
 Axes."




Str_DB[9]=new Array
Str_DB[9][0]="./Page/Model/NCKU/F04.Htm"
Str_DB[9][1]="Model: NCKU-F04 Worm And Worm Wheel Mechanism"
Str_DB[9][2]="Group: Gear Mechanisms  Description: Worm Is A Gear With One Or More Teeth Wrapped Helically On A Cylinder In Which The Pitch Of The Helix Is Less Than The Diameter \
Of The Gear. Worm Wheel Is The Gear That Mates With A Worm Gear. The Transmission Between Worm And Worm Wheel Is Similar To That Of Crossed Helical Gears. \
In General, The Axes Of The Worm And Worm Wheel Are Perpendicular To Each Other. The Transmission Of Worm And Worm Wheel Has The Advantages Of High \
Transmission Ratio, Compact Structure, Stable Motion, Precise Transmission, And Self-Lock Ability. So It Is Widely Used In Various Speed Reducers."




Str_DB[10]=new Array
Str_DB[10][0]="./Page/Model/NCKU/F05.Htm"
Str_DB[10][1]="Model: NCKU-F05 Rack And Pinion Mechanism"
Str_DB[10][2]="Group: Gear Mechanisms  Description: Rack Is A Segment Of A Gear Of Infinite Radius. And, The Gear Mated With The Rack Is Called The Pinion. The Transmission Between\
 Rack And Pinion Is Equivalent To A Rolling Contact Of A Cylinder On A Plane. It Can Transmit The Motion Between A Rotation And A Translation. The Rack And \
 Pinion Mechanisms Are Usually Adopted In The Steering Mechanisms In Automobiles."




Str_DB[11]=new Array
Str_DB[11][0]="./Page/Model/NCKU/F06.Htm"
Str_DB[11][1]="Model: NCKU-F06 Hyperboloid Gear Mechanism"
Str_DB[11][2]="Group: Gear Mechanisms  Description: This Mechanism Demonstrates The Transmission Of A Hyperboloid Gear Pair. A Hyperboloid Of Revolution Is The Surface Developed By\
 A Straight-Line Generatrix, Tangent To A Base Cylinder And At An Angle To The Axis Of The Base Cylinder, As It Is Revolved About The Axis Of The Base \
 Cylinder. The Hyperboloid Gear Is Generated Based On Formulating The Straight-Line, Which Is Used To Generate A Hyperboloid Of Revolution, As Its Tooth \
 Profile. The Hyperboloid Gear Pair Is Equivalent To A Rolling And Sliding Contact Between Two Hyperboloids. It Can Transmit The Motion Between Two Crossed \
 Axes. However, Since The Contact Of Two Meshing Hyperboloid Gears Is A Line Contact, There Will Be A Slipping Motion Along The Tooth Profile Of The \
 Hyperboloid Gears When Transmission. Thus The Transmission Of Hyperboloid Gears Has The Problem Of Greater Frictions."




Str_DB[12]=new Array
Str_DB[12][0]="./Page/Model/NCKU/F07.Htm"
Str_DB[12][1]="Model: NCKU-F07 Pin Gear Mechanism"
Str_DB[12][2]="Group: Gear Mechanisms Mechanism Description: The Tooth Profile Of The Pin Gear Is Formulated By A Number Of Pins Distributing On A Circular Disk. The Pin Gear Is Able To \
Transmit Precision Motion With Its Mating Gear. This Pin Gear Mechanism Transforms The Continuous Rotation Into The Repeated Reversing Motion, And It Can Be\
 Applied To The Timepiece And Pendulums."




Str_DB[13]=new Array
Str_DB[13][0]="./Page/Model/NCKU/F08.Htm"
Str_DB[13][1]="Model: NCKU-F08 Epicyclic Gear Train"
Str_DB[13][2]="Group: Gear Mechanisms  Description: Epicyclic Gear Train, Also Known As Planetary Gear Train, Is An Assembly Containing More Than One Pair Of Gears, In Which At \
Least One Gear Is Centered On The Axis About Which One Another Gear Rotates. In An Epicyclic Gear Train, The Extreme Gear With External Teeth Is Called The \
Sun Gear; The Extreme Gear With Internal Gear Teeth Is Called The Ring Gear; The Gear That Rotates On An Axle Whose Own Axis Is Constrained To Rotate About \
Another Axis Is Called The Planet Gear; And The Link On Which Gear Axles Are Arranged Is Called The Planet Carrier. A Distinct Characteristic Of Epicyclic \
Gear Trains Is That, Based On The Assembly Of Multiple Gears, It Can Produce Higher Transmission Ratio Than Those Of Other Simple Gear Trains. Besides, In \
Certain Situations, Each Gear In An Epicyclic Gear Train Is Rotatable. By Fixing Different Gears, The Gear Train Can Obtain Different Transmission Ratios. \
Hence The Epicyclic Gear Trains Are Broadly Applied In The Gearbox Of Automobiles."




Str_DB[14]=new Array
Str_DB[14][0]="./Page/Model/NCKU/F09.Htm"
Str_DB[14][1]="Model: NCKU-F09 Differential Gear Train"
Str_DB[14][2]="Group: Gear Mechanisms  Description: Differential Gear Trains Are The Most Broadly Used One Among Various Differential Mechanisms. Differential Mechanism Is A \
Mechanism From Which The Degrees Of Freedom Are Two And Which May Accept Two Inputs To Produce One Output Or To Resolve A Single Input Into Two Outputs. The\
 Differential Gear Train Is Usually Adopted As The Differential Mechanism In Automobiles. For The Rear-Wheel-Driving Automobiles, The Engine Power Can Be \
 Equally Outputted To The Two Rear Wheels Via The Transmission Shaft And The Internal Gear Sets. Based On The Kinematic Characteristics Of Differential Gear\
  Trains, The Sum Of Speeds Of The Two Wheels Will Be Constant. So It Can Avoid The Accident Due To The Same Rotational Speed Of The Two Wheels When \
  Automobile Is Turning. In The Other Words, When Driving Straight, The Two Wheel Speeds Are The Same; When Turning Right, The Left-Wheel Speed Is \
  Automatically Increased; And, When Turning Left, The Right-Wheel Speed Is Automatically Increased."




Str_DB[15]=new Array
Str_DB[15][0]="./Page/Model/NCKU/G01.Htm"
Str_DB[15][1]="Model: NCKU-G01 Belt Drive"
Str_DB[15][2]="Group: Belt And Chain Drives Description: Belt Drive Is A Power Transmission Device Used When The Distance Between Driving And Driven Shafts Is Far. The Advantages Of \
Using Belt Drives Include Smooth Transmission, Quiet Operation, Resistibility For Instantaneous Shakes And Over Loading, Lubrication Free, And Low Cost For \
Maintenance. However, It Also Has The Disadvantage Of Indeterminate Transmission, Which May Result The Slipping And Creep. The Shown Design Is The Simplest \
Belt Drive. It Consists Of A Belt, A Driving Wheel, A Driven Wheel, And A Frame. The Belt Is Wrapping Tightly On Two Cylindrical Wheels Whose Axes Are Fixed\
 On Frame. By Means Of The Tension Of The Belt, The Rotation Of The Driving Wheel Can Be Transmitted To The Driven Wheel. Nevertheless, If The Friction \
 Existed Between The Cylindrical Wheels And The Belt Is Large Enough, The Motion Can Also Be Transmitted Without Using Tension From The Belt."




Str_DB[16]=new Array
Str_DB[16][0]="./Page/Model/NCKU/G02.Htm"
Str_DB[16][1]="Model: NCKU-G02 Adjustable Belting"
Str_DB[16][2]="Group: Belt And Chain Drives Description: This Belt Drive Consists Of A Belt, A Driving Wheel, A Driven Wheel, A Guide Pulley, And A Frame. The Position Of The Driving \
Wheel Is Fixed, Whereas The Position Of The Driven Wheel Is Adjustable On The Track Of The Arc Slot. The Guide Pulley, Located Between The Driving And \
Driven Wheels, Is Used To Change The Direction Of Motion Of The Belt. It Also Makes The Tension Of The Belt Keeping Constant From Which The Motion Can Be \
Transmitted Smoothly While The Driven Wheel Locates At Different Positions."




Str_DB[17]=new Array
Str_DB[17][0]="./Page/Model/NCKU/G03.Htm"
Str_DB[17][1]="Model: NCKU-G03 Band Brake "
Str_DB[17][2]="Group: Belt And Chain Drives Description: The Band Brake Is A Braking Mechanism By Utilizing Belts. Originally, The Cylindrical Wheel Is Rotating Continuously. When The \
Bar Is Pushed Down, The Belt Whose Both Ends Are Connected To The Bar Will Bind The Wheel Tightly. Then The Friction Caused From The Contact Surface Of The \
Belt And The Wheel Will Be Generated, And Thus It Stops The Rotating Wheel Promptly."




Str_DB[18]=new Array
Str_DB[18][0]="./Page/Model/NCKU/G04.Htm"
Str_DB[18][1]="Model: NCKU-G04 Variable Speed Cone "
Str_DB[18][2]="Group: Belt And Chain Drives Description: The Variable Speed Cone Consists Of A Pair Of Cone Wheels And A Belt Wrapping On Them. By Moving The Wrapping Location Of The \
Belt Along The Direction Of The Cone Axes, The Output Speed Can Be Different Based On The Same Input Speed. Thus It Is The One Of The Continuous Variable \
Speed Transmissions."




Str_DB[19]=new Array
Str_DB[19][0]="./Page/Model/NCKU/H01.Htm"
Str_DB[19][1]="Model: NCKU-H01 Ratchet Mechanism"
Str_DB[19][2]="Group: Ratchet Mechanism Description: It Is The Simplest Ratchet Mechanism Comprising Of An Oscillating Arm, A Pawl, A Ratchet, And A Frame. When The Oscillating Arm \
Is Manipulated Clockwise, The Ratchet Is Followed By The Push Of The Pawl. When The Oscillating Arm Is Manipulated Counterclockwise, The Pawl Slips On The \
Teeth Of The Ratchet In Which The Ratchet Wheel Keeps Station. This Mechanism Provides A Uni-Direction Intermittent Motion. It Is Usually Used In Feed \
Mechanisms, Lifting Jacks, Clocks, And Watches, Etc."




Str_DB[20]=new Array
Str_DB[20][0]="./Page/Model/NCKU/I01.Htm"
Str_DB[20][1]="Model: NCKU-I01 Screw Press"
Str_DB[20][2]="Group: Lower Pairs Description: One Of The Typical Applications Of Screw Mechanisms Is The Effort-Saving Devices. And The Screw Presses Are A Representative \
Application Of Effort-Saving Devices. The Fundamental Principle Of The Screw Presses Is, Via The Screw Motion, To Convert A Small Input Torque As An \
Extremely Large Output Force. For The Shown Design, This Screw Press Is Constructed With A Screw And A Frame. On The Lower End Of The Screw, A Press Plate \
Is Attached To The Screw And The Workpiece Can Be Placed Under The Press Plate To Wait For Pressing. When A Torque Is Inputted Into The Screw, The Screw \
Will Output A Translational Motion, Which Forces The Press Plate Pressing The Workpiece In A Very Large Force."




Str_DB[21]=new Array
Str_DB[21][0]="./Page/Model/NCKU/J01.Htm"
Str_DB[21][1]="Model: NCKU-J01 Flexible Coupling "
Str_DB[21][2]="Group: Couplings Description: The Flexible Coupling Is A Coupling That Uses Flexible Members To Join Two Shafts. Especially, Because Of The Property Of \
Flexible Members, The Flexible Coupling Can Conduct The Motion Between Two Shafts And The Axial Orientations Of These Two Shafts Are Free Of Limits I.E., \
The Locations Of The Two Connected Shafts Could Be Arbitrary. For The Shown Design, The Utilized Flexible Member Is The Spring. The Spring Is Connected To \
The Two Shafts In Which One Of The Shafts Has The Fixed Axial Orientation, While The Other One Can Arbitrarily Adjust Its Axial Orientation By Moving Along \
The Disk On The Frame."




Str_DB[22]=new Array
Str_DB[22][0]="./Page/Model/NCKU/J02.Htm"
Str_DB[22][1]="Model: NCKU-J02 Double-Roller Slot Coupling"
Str_DB[22][2]="Group: Couplings Description: This Mechanism Comprises Of A Cross Slot And A Connecting Member With Two Rollers. It Is Used For The Transmission Between Two \
Parallel But Not Colinear Shafts. The Two-Roller Connecting Member And Cross Slot Are Connected To The Driving And Driven Shafts, Respectively. When The \
Driving Shaft Is Rotated, The Two Rollers Will Periodically Roll Inside The Cross Slot Back And Forth. Accordingly, The Driven Shaft Can Be Motivated By \
This Rolling Contact. However, The Rotational Speed Of The Output Shaft Is Shifted From The Input Shaft By One Half, I.E., The Output Shaft Can Complete One\
 Revolution As The Input Shaft Runs Two Revolutions. This Mechanism Can Be Regarded As One Of The Linkage Mechanisms. The Rolling Contact Between The Roller\
  And The Slot Is Merely A Degeneration From The Slider-Crank Mechanisms."




Str_DB[23]=new Array
Str_DB[23][0]="./Page/Model/NCKU/K01.Htm"
Str_DB[23][1]="Model: NCKU-K01 Disk-Roller Friction Wheels "
Str_DB[23][2]="Group: Friction Drives  Description: This Mechanism Consists Of A Disk Friction Wheel, A Roller Friction Wheel, And A Frame. It Is Used For The Transmission Between\
 Two Perpendicular But Not Intersecting Shafts With Constant Transmission Ratio. The Disk Is The Driving Wheel Connecting To The Input Shaft, While The \
 Roller Is The Driven Wheel Connecting To The Output Shaft. When The Input Shaft Rotates, The Motion Is Transmitted To The Output Shaft Through The Friction\
  Between The Disk And Roller. Besides, The Roller Can Adjust Its Position Along The Diameter Of The Disk For Obtaining Different Transmission Ratio."




Str_DB[24]=new Array
Str_DB[24][0]="./Page/Model/NCKU/A01.Htm"
Str_DB[24][1]="Model: NCKU-L01 Paddle Wheel Mechanism "
Str_DB[24][2]="Group: Compound Mechanisms Description: This mechanism appears in the water wheel applications and the paddle wheel machines. It primarily \
consists of three four-bar linkages. Each four-bar linkage has an arm for receiving the input force from the crank and a link for joining a paddle. The \
orientations of the paddles are controlled by the linkages so that the paddles can ladle water from the bottom to the top."


Str_DB[25]=new Array
Str_DB[25][0]="./Page/Model/NCKU/L02.Htm"
Str_DB[25][1]="Model: NCKU-L02 Double-eccentric Linkage Mechanism"
Str_DB[25][2]="Group: Compound Mechanisms Description: This mechanism can be treated as a combination and metamorphism of two slider-crank mechanisms. The \
two cranks are both hinged to the driving link and are connected with two disks, respectively. When the driving link is motivated, each crank will produce \
an eccentric rotation with respect to the center of its attached disk. Then, the motions caused from the two eccentric rotations are transmitted through the\
 linkages and finally result a reciprocating linear motion to the same slider. Besides, an adjustable four-bar linkage is attached to these two linkages. \
 When the link lengths of the adjustable four-bar linkage are varied, the stroke of the slider will be changed."


Str_DB[26]=new Array
Str_DB[26][0]="./Page/Model/NCKU/L03.Htm"
Str_DB[26][1]="Model: NCKU-L03 Gear-slider Mechanism "
Str_DB[26][2]="Group: Compound Mechanisms Description: This mechanism comprises of a fan-pinion, a rack, and a frame with slot. The input crank is connected\
 to the fan-pinion and the rack mates with the fan-pinion in forms of the internal gear pair. On the other hand, the rack is also served as a slider that \
 can slide inside the slot on the frame. Hence, when the crank is continuously rotating, the fan-pinion will guide the rack reciprocally translating in the \
 slot."


Str_DB[27]=new Array
Str_DB[27][0]="./Page/Model/NCKU/L04.Htm"
Str_DB[27][1]="Model: NCKU-L04 Crank-and-rocker Mechanism with a Ratchet"
Str_DB[27][2]="Group: Compound Mechanisms Description: This mechanism is constructed based on a crank-and-rocker mechanism integrated with a ratchet \
mechanism. First, the crank is the input link with a continuous rotation and the rocker is the output link with a reciprocating oscillation. Meanwhile, the \
rocker is also the oscillating arm of the ratchet mechanism. It attaches a pawl that can engage with the ratchet. When the rocker is oscillating, the pawl \
will push the ratchet periodically. Thus the ratchet is motivated with a uni-direction stepping motion. Furthermore, the rocker is also equipped with two \
adjustable knobs on the circular track. If the distance between the two knobs is adjusted, the stepping length of the ratchet will be changed."


Str_DB[28]=new Array
Str_DB[28][0]="./Page/Model/NCKU/L05.Htm"
Str_DB[28][1]="Model: NCKU-L05 Gear Transmission with Clutch"
Str_DB[28][2]="Group: Compound Mechanisms Description: This mechanism comprises of several gear sets, including two straight bevel gear pairs and one worm \
and worm wheel, and a clutch. The clutch is formed by two symmetrical friction wheels and is manipulated by an arm that can be controlled for determining \
the rotating direction, i.e., counterclockwise or clockwise, of the first bevel gear pair. After the rotating direction of the first bevel gear pairs has \
been determined, the motion can therefore be inputted from the crank to the gears. Then the transmission will go through the first bevel gear pair, the \
second bevel gear pair, and the worm and worm wheel. Finally, it outputs a motion at the indicator. Since this mechanism compounds several gear mechanisms \
and a clutch, it has the functions of variable directions of transmissions and speed reduction."


Str_DB[29]=new Array
Str_DB[29][0]="./Page/Model/NCKU/L06.Htm"
Str_DB[29][1]="Model: NCKU-L06 Belt-gear-friction Transmission"
Str_DB[29][2]="Group: Compound Mechanisms Description: This mechanism comprises of three major sections: the belt drive, gear transmission, and friction \
drive. The belt drive consists of a belt, a driving pulley, and a driven pulley with three layers; the gear transmission consists of a gear mechanism with \
five spur gears; the friction transmission is appeared between the co-axial driven pulley layers and the gears by using the frictions between those and \
their axis. First, the power is inputted from the crank on the driving pulley. By means of the belt drive, the power is transmitted to the front first layer\
 of the driven pulley. Then, it goes through the gear mechanism and, finally, arrives at the third layer of the driven pulley. Consequently, it concludes \
 the overall transmission. Oppositely, the power transmission can also be started at the third layer of the driven pulley and ended at the first layer. \
 However, the transmission efficiency of the backward operation will be worse than that of the forward operation due to the early appearance of the friction\
  transmission."


Str_DB[30]=new Array
Str_DB[30][0]="./Page/Model/NCKU/M01.Htm"
Str_DB[30][1]="Model: NCKU-M01 Ball Valve "
Str_DB[30][2]="Group: Mechanical Element Models Description: Ball valves are a species of valves having a ball-shaped closure member. It is usually used for\
 stopping and starting flow, flow diversion, etc. and best used for on-off service as well as moderate throttling situations that require minimal accuracy. \
 The shown model illustrates the fundamental concept of the ball valves. It is a sectional view of a basic ball valve installing on the pipe. When the ball \
 is stationary on the outlet of the pipe, the valve is closed and the flow cannot be issued from the pipe. If the ball is lifted by either the flow pressure\
  or the manual operation, the valve is opened and therefore the flow can be successfully issued from the pipe through its outlet."


Str_DB[31]=new Array
Str_DB[31][0]="./Page/Model/NCKU/M02.Htm"
Str_DB[31][1]="Model: NCKU-M02 Pressure Relief Valve "
Str_DB[31][2]="Group: Mechanical Element Models Description: Pressure relief valves are pressure-relieving devices which automatically relieve a pressure \
system of excess pressure when abnormal operating conditions cause the pressure to exceed a set limit, and re-close when the abnormal pressure recedes again\
 below the set limit. The shown model is one of the various types of pressure relief valves. The flow is originally full with the lower-abdominal pipe. When\
  the pressure in the lower-abdominal pipe exceeds the set limit defined by the spring force, the valve will be opened by the force from the flow pressure. \
  The flow then goes into the upper-abdominal pipe and finally is rejected through the left pipe. As the pressure in the lower-abdominal pipe recedes below \
  the set limit, the valve will be re-closed again."


Str_DB[32]=new Array
Str_DB[32][0]="./Page/Model/NCKU/M03.Htm"
Str_DB[32][1]="Model: NCKU-M03 Adjustable Pressure Relief Valve "
Str_DB[32][2]="Group: Mechanical Element Models Description: The function of this valve is identical to that of previous one, but the pre-loading of this \
valve is adjustable. A pendulum set on a lever is used to provide the pre-loading for this valve. As the position of the pendulum is changed, the magnitude \
of the pre-loading is accordingly adjusted."


Str_DB[33]=new Array
Str_DB[33][0]="./Page/Model/NCKU/N01.Htm"
Str_DB[33][1]="Model: NCKU-N01 Turbine "
Str_DB[33][2]="Group: Mechanical Element Models Description: Turbine is a machine used to transfer the energy of a current of fluid (as water, steam, or \
air) to the mechanical energy which is usually outputted in forms of a rotating spindle. The core of the shown turbine has five curve-vane disks, three \
painted by red for indicating the rotors and two painted by blue for indicating the stators. In order to get a greater kinetic energy, each stator is \
arranged between two rotors for guiding the flow, by the curve vanes, with a better impact angle on the rotor¡¦s curve vanes. The flow is injected into the \
turbine from the left pipe and rejected through the right pipe. The rotor can be rotated by the flow and outputs energy through the shaft to the right \
pulley that can be connected to other mechanical devices for transmission."


Str_DB[34]=new Array
Str_DB[34][0]="./Page/Model/NCKU/N02.Htm"
Str_DB[34][1]="Model: NCKU-N02 Turbine with Gear Reducer "
Str_DB[34][2]="Group: Machine System Models Description: The working concept of this turbine is identical to that of the previous model. The flow is \
injected from the upper pipe and then pushes the red rotor to produce kinetic energy to the shaft. Besides, the shaft is connected to a gear reducer, which\
 is formed by two straight bevel gears, for generating a greater output torque."


Str_DB[35]=new Array
Str_DB[35][0]="./Page/Model/NCKU/N03.Htm"
Str_DB[35][1]="Model: NCKU-N03 Vertical Steam Engine"
Str_DB[35][2]="Group: Machine System Models Description: Different to horizontal steam engines, the cylinder of the vertical steam engines is set vertically\
 in which the piston can slide vertically. Owing to the vertical position, there is no tendency to side wear of cylinder or piston. The packing-rings are \
 self-adjusting, and work free but tight. The cylinder of this vertical steam engine is set on its upper portion. Inside the cylinder, a piston is connected\
  to a connecting rod and a crank, as appeared below the cylinder, to output the power to a wheel behind the model. Besides, an eccentric linkage is \
  attached to the crank. By following the rotation of the crank, it can control the intake valve of the cylinder to open and close the pipe in time."


Str_DB[36]=new Array
Str_DB[36][0]="./Page/Model/NCKU/N04.Htm"
Str_DB[36][1]="Model: NCKU-N04 Root's Blower Chamber Wheel Mechanism"
Str_DB[36][2]="Group: Machine System Models Description: This mechanism was first proposed by Root in 1854. When it works, the fluid under the chamber is \
continuously drawn into the chamber and then rejected through the jet located at the top of the chamber. In the back of the chamber, a pair of spur gears is\
 equipped and connects two particular links with figure eight inside the chamber. When the gear is driven, the two particular links will be rotated with \
 opposite directions. And, based on the specific geometry and mating timing, the fluid under the chamber can be drawn into the chamber and then be jetted \
 out to the chamber. The well-known ancient blowers, for example, are representative for this operation. It continuously blows air through the jet so that \
 plentiful oxygen can be poured into the furnace for increasing the burning temperature."


Str_DB[37]=new Array
Str_DB[37][0]="./Page/Model/NCKU/N05.Htm"
Str_DB[37][1]="Model: NCKU-N05 Horizontal Steam Engine"
Str_DB[37][2]="Group: Machine System Models Description: Steam engine is an engine whose power is generated from vapor. In the early stage, it was broadly \
used in industrial factories and transportation. It also played an important role in the era of Industrial Revolution. The shown horizontal steam engine \
model has a pipe on its left for connecting the boiler to introduce the vapor into its cylinder. Then the introduced vapor can force the piston back and \
forth. The piston is linked with a linkage that is used to transmit piston power to the flywheel (or wheel) on its right. Besides, there also exists a \
linkage that is used to control the intake valve inside the engine. A bar of the linkage is designated for controlling the open and close of the intake \
valve. When the bar is at right, the valve is opened from which the vapor can enter into the engine; when the bar is at left, the valve is closed from which\
 the vapor is stopped outside the engine. While the vapor is permitted for entrance, the valve will move right and left alternately according to the piston \
 timing to open the right and left pipes, respectively. Thus it can promote a periodically reciprocal push force on the piston, that causes the forward and \
 the backward stroke are both of the power strokes."


Str_DB[38]=new Array
Str_DB[38][0]="./Page/Model/NCKU/N06.Htm"
Str_DB[38][1]="Model: NCKU-N06 Crane"
Str_DB[38][2]="Group: Machine Systems Description: The crane is an effort-saving device based on the application of gear reducers. The weight is hanged by \
an iron chain whose end is connected to the lower-speed gear shaft. When the input torque is entered from the higher-speed gear shaft, the torque will be \
magnified through the gear train. Then, it will be outputted to the lower-speed gear shaft. The shown crane model is manipulated by three control sticks, \
which are used for lifting weight, turning and braking device, respectively."


Str_DB[39]=new Array
Str_DB[39][0]="./Page/Model/NCKU/N07.Htm"
Str_DB[39][1]="Model: NCKU-N07 Four-stroke Engine-1"
Str_DB[39][2]="Group: Machine System Models Description: This is the basic structure of a four-stroke engine. In the beginning, the engine draws the \
mixture, including fuel and fresh air, into the cylinder. The mixture is then compressed by the piston. Then, the gases are burned and expanded to push the \
piston causing the rotation of the crank. And, finally, the remaining gases are exhausted. So, it is so-called a four-stroke (i.e., the intake, compression,\
 power, and exhaust stroke) engine."


Str_DB[40]=new Array
Str_DB[40][0]="./Page/Model/NCKU/N08.Htm"
Str_DB[40][1]="Model: NCKU-N08 Transmission System in Automobiles"
Str_DB[40][2]="Group: Machine System Models Description: This model explains the power transmission in a general automobile. Originally, the power is \
produced from the engine. It then passes through the clutch, gearbox, transmission shaft, and differential gear train, and finally arrives at the rear \
wheels. Almost all basic mechanisms used for transmission in automobiles are included in this model. So this model illustrates a typical application of the \
mechanism systems."


Str_DB[41]=new Array
Str_DB[41][0]="./Page/Model/NCKU/N09.Htm"
Str_DB[41][1]="Model: NCKU-N09 Valve-control Mechanism in Four-stroke Engines"
Str_DB[41][2]="Group: Machine System Models Description: This model illustrates the timing control strategy between the piston and intake valve of the \
engine. In this engine, the piston is connected to a crank through a connecting rod. The crank is also attached to a gear mechanism in which the tooth \
numbers of the two gears are different. A pin, which is used to simulate a cam, is set on the big gear to push the bottom link for opening the intake valve.\
 Since the tooth number of the big gear is double of that of the small gear, the intake valve will be opened once while the smaller gear rotates two \
 revolutions (i.e., the piston travels four strokes)."


Str_DB[42]=new Array
Str_DB[42][0]="./Page/Model/NCKU/N10.Htm"
Str_DB[42][1]="Model: NCKU-N10 Valve-control Mechanism in Horizontal Steam Engines"
Str_DB[42][2]="Group: Machine System Models Description: This model primarily illustrates the control strategy of the linkage in determining the open and \
close of the intake valve in a horizontal steam engine. The timing motion of the intake valve in this model is identical to that of the previous horizontal \
steam engine model. But the movement of the linkage is emphasized in this model. From the back view of the model, the moving process of the linkage in \
controlling the intake valve of the steam engine can be understood clearly."


Str_DB[43]=new Array
Str_DB[43][0]="./Page/Model/NCKU/N11.Htm"
Str_DB[43][1]="Model: NCKU-N11 Four-stroke Engine-2"
Str_DB[43][2]="Group: Machine System Models Description: The working process of this four-stroke engine is identical to that of the previous one. \
Nevertheless, this model additionally conducts an auxiliary electric power which is used to drive a light bulb located in the cylinder. When this model is \
demonstrating the power-stroke stage, the light bulb will be turned on automatically. Thus the demonstration of the working cycle of the engine would be \
easier realized."


Str_DB[44]=new Array
Str_DB[44][0]="./Page/Model/ntu/D01.Htm"
Str_DB[44][1]="Model: NTU-D01 Slider-crank Mechanism "
Str_DB[44][2]="Group: Slider-crank Mechanisms  Description: Slider-crank mechanism is a four-bar mechanism with a crank, a connecting rod, and a slider in which the frame forms one element of the prismatic pair. The function of the slider-crank mechanisms is to make a motion transformation between a rotation and a translation. Generally, the input power is exerted on the crank and the output is the slider. For example, the mechanical press is one application of the slider-crank mechanisms. The power generated from motor is inputted to the crank, the mold is attached to the slider, and the raw materials are placed on the frame. When the crank of the press is rotating continuously, the slider can press the raw materials reciprocally."


Str_DB[45]=new Array
Str_DB[45][0]="./Page/Model/ntu/D02.Htm"
Str_DB[45][1]="Model: NTU-D02 Quick-return Mechanism "
Str_DB[45][2]="Group: Slider-crank Mechanisms Description: Broadly used in machining centers, the quick-return mechanism is in general formed by combining a four-bar linkage and a slider-crank mechanism or a slider-crank mechanism and its kinematic inversion. When the crank is driven with a constant speed, the slider is stimulated with a faster forward stroke and a slower backward stroke for saving time."

Str_DB[46]=new Array
Str_DB[46][0]="./Page/Model/ntu/D03.Htm"
Str_DB[46][1]="Model: NTU-D03 Scotch-yoke Mechanism"
Str_DB[46][2]="Group: Slider-crank Mechanisms Description: The Scotch-yoke mechanism is a four-bar mechanism in which a crank is connected by a slider with another link which, in turn, forms a prismatic pair with the frame. This mechanism is equivalent to a slider-crank mechanism in which the length of the connecting rod is infinite. When the crank is driven with a constant speed, the slider moving on the frame can output a simple harmonic motion. For applications, this mechanism can be used in the testing machines for simulating the simple harmonic vibration. It can also be adopted for driving the pumps and compressors. In comparison to the slider-crank mechanisms, the scotch-yoke mechanisms possess the lower mechanical efficiency due to the friction of the sliding motions. Hence it is only adoptable for the small machines operated under light loading."

Str_DB[47]=new Array
Str_DB[47][0]="./Page/Model/ntu/E01.Htm"
Str_DB[47][1]="Model: NTU-E01 Disk Cam with Roller Follower"
Str_DB[47][2]="Group: Cam Mechanisms  Description: This cam mechanism comprises of a heart-like disk cam, a roller follower, and a frame. When the cam is driven, the follower outputs a reciprocating linear motion."

Str_DB[48]=new Array
Str_DB[48][0]="./Page/Model/ntu/E02.Htm"
Str_DB[48][1]="Model: NTU-E02 Disk Cam with Flat Face Follower"
Str_DB[48][2]="Group: Cam Mechanisms  Description: This cam mechanism comprises of a disk cam, a flat face follower, and a frame. When the cam is driven, the follower outputs a reciprocating linear motion."

Str_DB[49]=new Array
Str_DB[49][0]="./Page/Model/ntu/E03.Htm"
Str_DB[49][1]="Model: NTU-E03 Double-disk Cam Mechanism "
Str_DB[49][2]="Group: Cam Mechanisms Description: This cam mechanism has two disk cams, the driving cam and driven cam, to produce a variable speed ratio under a constant input. The two cams are both pivoted at the frame. Besides, a connecting rod is connected to the two cams, with revolute joints, to retain a constant distance between these two cams. Since the distance between the two joints of the connecting rod remains constant, the driven cam will be forced to keep contact with the driving cam. Thus, when the driving cam is actuated with a constant-speed rotation, the driven cam will output a variable-speed rotation."


Str_DB[50]=new Array
Str_DB[50][0]="./Page/Model/ntu/F01.Htm"
Str_DB[50][1]="Model: NTU-F01 Spur Gear Mechanism"
Str_DB[50][2]="Group: Gear Mechanisms Description: This mechanism demonstrates the transmission of a spur gear pair. Spur gear is the cylindrical gear, which forms teeth on a cylindrical surface, having external teeth. The spur gear pair transmits a rotation between two parallel axes. The transmission efficiency of a spur gear pair can even achieve 98 percent."

Str_DB[51]=new Array
Str_DB[51][0]="./Page/Model/ntu/F02.Htm"
Str_DB[51][1]="Model: NTU-F02 Crossed Helical Gear Mechanism"
Str_DB[51][2]="Group: Gear Mechanisms Description: This mechanism demonstrates the transmission of a crossed helical gear pair. The crossed helical gear pair comprises of two matching helical gears with crossed axes. It can transmit the motion between two crossed axes."

Str_DB[52]=new Array
Str_DB[52][0]="./Page/Model/ntu/F03.Htm"
Str_DB[52][1]="Model: NTU-F03 Straight Bevel Gear Mechanism"
Str_DB[52][2]="Group: Gear Mechanisms Description: This mechanism demonstrates the transmission of a straight bevel gear pair. The straight bevel gear is a gear with teeth formed on a conical surface. The transmission of a straight bevel gear pair is equivalent to the rolling contact between two semi-cones. It can transmit the motion between two intersecting axes with any intersecting angels. For example, the shown mechanism illustrates two mating straight bevel gears with orthogonal axes."

Str_DB[53]=new Array
Str_DB[53][0]="./Page/Model/ntu/F04.Htm"
Str_DB[53][1]="Model: NTU-F04 Worm and Worm Wheel Mechanism"
Str_DB[53][2]="Group: Gear Mechanisms Description: Worm is a gear with one or more teeth wrapped helically on a cylinder in which the pitch of the helix is less than the diameter of the gear. Worm wheel is the gear that mates with a worm gear. The transmission between worm and worm wheel is similar to that of crossed helical gears. In general, the axes of the worm and worm wheel are perpendicular to each other. The transmission of worm and worm wheel has the advantages of high transmission ratio, compact structure, stable motion, precise transmission, and self-lock ability. So it is widely used in various speed reducers."

Str_DB[54]=new Array
Str_DB[54][0]="./Page/Model/ntu/F05.Htm"
Str_DB[54][1]="Model: NTU-F05 Rack and Pinion Mechanism"
Str_DB[54][2]="Group: Gear Mechanisms Description: The rack can be regarded as a gear with infinite radius. And, the gear mated with the rack is called the pinion. The transmission between them is equivalent to the rolling contact of a cylinder on a plane. It can transmit the rotation into the translation, and vice versa. So it usually applied for the steering mechanisms in automobiles."

Str_DB[55]=new Array
Str_DB[55][0]="./Page/Model/ntu/F06.Htm"
Str_DB[55][1]="Model: NTU-F06 Hyperboloid Gear Mechanism"
Str_DB[55][2]="Group: Gear Mechanisms Description: This mechanism demonstrates the transmission of a hyperboloid gear pair. A hyperboloid of revolution is the surface developed by a straight-line generatrix, tangent to a base cylinder and at an angle to the axis of the base cylinder, as it is revolved about the axis of the base cylinder. The hyperboloid gear is generated based on formulating the straight-line, which is used to generate a hyperboloid of revolution, as its tooth profile. The hyperboloid gear pair is equivalent to a rolling and sliding contact between two hyperboloids. It can transmit the motion between two crossed axes. However, since the contact of two meshing hyperboloid gears is a line contact, there will be a slipping motion along the tooth profile of the hyperboloid gears when transmission. Thus the transmission of hyperboloid gears has the problem of greater frictions."

Str_DB[56]=new Array
Str_DB[56][0]="./Page/Model/ntu/F07.Htm"
Str_DB[56][1]="Model: NTU-F07 Pin Gear Mechanism"
Str_DB[56][2]="Group: Gear Mechanisms Description: The tooth profile of the pin gear is formulated by a number of pins distributing on a circular disk. The pin gear is able to transmit precision motion with its mating gear. This pin gear mechanism transforms the continuous rotation into the repeated reversing motion, and it can be applied to the timepiece and pendulums."

Str_DB[57]=new Array
Str_DB[57][0]="./Page/Model/ntu/F08.Htm"
Str_DB[57][1]="Model: NTU-F08 Epicyclic Gear Train (1) "
Str_DB[57][2]="Group: Gear Mechanisms Description: The epicyclic gear train, also called the planetary gear train, is derived from appropriate combination of two or more gears and at least one gear axis is rotated about another gear axis. As shown in the figure, this epicyclic gear train comprises of three gears, where the central gear is called the sun gear, the outmost gear is called the ring gear, the gear between sun gear and ring gear is the planet gear, and the sun gear and planet gear are connected by the element called the arm. The axis of the sun gear and the ring gear are grounded. The planet gear can revolve on its own axis and have a revolution around the sun gear. So this mechanism has two degrees of freedom."

Str_DB[58]=new Array
Str_DB[58][0]="./Page/Model/ntu/F09.Htm"
Str_DB[58][1]="Model: NTU-F09 Epicyclic Gear Train (2) "
Str_DB[58][2]="Group: Gear Mechanisms Description: This is a simple epicyclic gear train with one sun gear, two planet gears, and one arm. The sun gear is served as the frame and the arm connecting two planet gears is served as the input link. When the arm is driven, the two planet gears will revolve round the sun gear."

Str_DB[59]=new Array
Str_DB[59][0]="./Page/Model/ntu/F10.Htm"
Str_DB[59][1]="Model: NTU-F10 Epicyclic Gear Train (3) "
Str_DB[59][2]="Group: Gear Mechanisms Description: This is an epicyclic gear train with a friction wheel. The friction wheel is connected to the sun gear of the gear train. When the the friction wheel is releasing free, the sun gear will be rotated by following the input crank; When the friction wheel is held, the sun gear will be fixed and the planet gear will run around the sun gear."

Str_DB[60]=new Array
Str_DB[60][0]="./Page/Model/ntu/F11.Htm"
Str_DB[60][1]="Model: NTU-F11 Planetary Bevel Gear Train"
Str_DB[60][2]="Group: Gear Mechanisms Description: The planetary bevel gear train is an epicyclic gear train with bevel gears. Compared to the planetary spur gear trains, planetary bevel gear trains have the advantages of space-saving. Thus it can obtain a higher transmission ratio by using fewer gears."

Str_DB[61]=new Array
Str_DB[61][0]="./Page/Model/ntu/F12.Htm"
Str_DB[61][1]="Model: NTU-F12 Differential Gear Train "
Str_DB[61][2]="Group: Gear Mechanisms Description: Differential gear trains are the most broadly used one among various differential mechanisms. Differential mechanism is a mechanism from which the degrees of freedom are two and which may accept two inputs to produce one output or to resolve a single input into two outputs. The differential gear train is usually adopted as the differential mechanism in automobiles. For the rear-wheel-driving automobiles, the engine power can be equally outputted to the two rear wheels via the transmission shaft and the internal gear sets. Based on the kinematic characteristics of differential gear trains, the sum of speeds of the two wheels will be constant. So it can avoid the accident due to the same rotational speed of the two wheels when automobile is turning. In the other words, when driving straight, the two wheel speeds are the same; when turning right, the left-wheel speed is automatically increased; and, when turning left, the right-wheel speed is automatically increased."

Str_DB[62]=new Array
Str_DB[62][0]="./Page/Model/ntu/F13.Htm"
Str_DB[62][1]="Model: NTU-F13 Differential Gear Train and Spur Gears"
Str_DB[62][2]="Group: Gear Mechanisms Description: This mechanism comprises of three bevel gears and two spur gears. The bevel gear near to the input crank is served as the frame and the other gears are all movable. When inputting a rotation from the crank, the bigger spur gear will be rotated and the middle bevel gear whose axis is set on the circle of the wheel of the bigger spur gear will rotate about its own axis and revolve about the axis of input crank. Besides, the smaller spur gear will be driven by the bigger spur gear."

Str_DB[63]=new Array
Str_DB[63][0]="./Page/Model/ntu/F14.Htm"
Str_DB[63][1]="Model: NTU-F14 Differential Spur Gear Train"
Str_DB[63][2]="Group: Gear Mechanisms Description: This mechanism is a differential gear train whose gears are all spur gears. It is basically a combination of two planetary gear trains on which the two sun gears are coaxial. The function of this mechanism is similar to the previous differential gear train. When the mechanism is driven and both wheels are releasing free, all spur gears are running; when the right wheel is held, the right sun gear will become fixed but the other gears are still rotatable; when the left wheel is held, the left sun gear will become fixed but the other gears are still rotatable. This mechanism is applicable for the situation that requires two controllable inputs."

Str_DB[64]=new Array
Str_DB[64][0]="./Page/Model/ntu/F15.Htm"
Str_DB[64][1]="Model: NTU-F15 Gear Transmission"
Str_DB[64][2]="Group: Gear Mechanisms Description: This mechanism illustrates a transmission in a set of gear mechanisms. It includes the spur gears, lantern gear and crown gear, straight bevel gear pairs, worm and worm wheel. The lantern gear is a gear of which the gear teeth are cylindrical cogs with axes parallel to the gear axis. And, the crown gear is a bevel gear with a reference cone angle of 90 degree."

Str_DB[65]=new Array
Str_DB[65][0]="./Page/Model/ntu/G01.Htm"
Str_DB[65][1]="Model: NTU-G01 Adjustable Belting"
Str_DB[65][2]="Group: Belts & Chains Description: This belt drive consists of a belt, a driving wheel, a driven wheel, a guide pulley, and a frame. The position of the driving wheel is fixed, whereas the position of the driven wheel is adjustable on the track of the arc slot. The guide pulley, located between the driving and driven wheels, is used to change the direction of motion of the belt. It also makes the tension of the belt keeping constant from which the motion can be transmitted smoothly while the driven wheel locates at different positions."

Str_DB[66]=new Array
Str_DB[66][0]="./Page/Model/ntu/G02.Htm"
Str_DB[66][1]="Model: NTU-G02 Variable Speed Cone"
Str_DB[66][2]="Group: Belts & Chains Description: The variable speed cone consists of a pair of cone wheels and a belt wrapping on them. By moving the wrapping location of the belt along the direction of the cone axes, the output speed can be different based on the same input speed. Thus it is the one of the continuous variable speed transmissions."

Str_DB[67]=new Array
Str_DB[67][0]="./Page/Model/ntu/G03.Htm"
Str_DB[67][1]="Model: NTU-G03 Chain Drive"
Str_DB[67][2]="Group: Belts & Chains Description: When the distance between two shafts is far and it requires a determinate transmission, the linkage mechanisms, cam mechanisms, and gear mechanisms as well as the belt drives are not suitable for such situation. At this time, the chain drives are the most popular one for transmission. The reasons of using chain drives rather than belt drives are that the chain drives have greater strength, better loading capability, and greater transmission power. Besides, the chain drives have no problems on slipping, creep, and material deformation which may occur in belt drives. Furthermore, the chain drive also has a compact structure and a long working life. However, since the weight of chains is greater than that of belts, the transmission efficiency of chain drives is less than that of belt drives. In addition, the chain drives need to consider the problems on lubrication and dust-proof. In the shown mechanism, it illustrates the basic concept of a chain drive. It consists of a chain, two sprocket wheels, and a frame. The chain is wrapping on the two sprocket wheels from which the motion of the driving wheel can be transmitted to the driven wheel."

Str_DB[68]=new Array
Str_DB[68][0]="./Page/Model/ntu/H01.Htm"
Str_DB[68][1]="Model: NTU-H01 Ratchet Mechanism"
Str_DB[68][2]="Group: Ratchets Description: It is the simplest ratchet mechanism comprising of an oscillating arm, a pawl, a ratchet, and a frame. When the oscillating arm is manipulated clockwise, the ratchet is followed by the push of the pawl. When the oscillating arm is manipulated counterclockwise, the pawl slips on the teeth of the ratchet in which the ratchet wheel keeps station. This mechanism provides a uni-direction intermittent motion. It is usually used in feed mechanisms, lifting jacks, clocks, and watches, etc."

Str_DB[69]=new Array
Str_DB[69][0]="./Page/Model/ntu/I01.Htm"
Str_DB[69][1]="Model: NTU-I01 Screw Press "
Str_DB[69][2]="Group: Screw Mechanisms  Description: One of the typical applications of screw mechanisms is the effort-saving devices. And the screw presses are a representative application of effort-saving devices. The fundamental principle of the screw presses is, via the screw motion, to convert a small input torque as an extremely large output force. For the shown design, this screw press is constructed with a screw and a frame. On the lower end of the screw, a press plate is attached to the screw and the workpiece can be placed under the press plate to wait for pressing. When a torque is inputted into the screw, the screw will output a translational motion, which forces the press plate pressing the workpiece in a very large force."

Str_DB[70]=new Array
Str_DB[70][0]="./Page/Model/ntu/I02.Htm"
Str_DB[70][1]="Model: NTU-I02 Lead Screw Mechanism"
Str_DB[70][2]="Group: Screw Mechanisms  Description: Lead screw, comprising of a screw and one or more nut sliders mated with the screw, is a rotating screw for moving the sliders at a constant speed. Since the lead screw has the advantage of precise transmission, it is usually used in the precision devices, e.g., the lathes, machining centers, etc. For the shown design, this lead screw mechanism comprises of a screw with two opposite thread directions, i.e., the right-handed thread and left-handed thread, two nut sliders, and a frame. When the screw is driven, the two nut sliders will move together along the rotation axis of the screw. Since these two nut sliders mate the screw with opposite thread directions, they will move in opposite directions. "

Str_DB[71]=new Array
Str_DB[71][0]="./Page/Model/ntu/J01.Htm"
Str_DB[71][1]="Model: NTU-J01 Flexible Coupling"
Str_DB[71][2]="Group: Couplings Description: The flexible coupling is a coupling that uses flexible members to join two shafts. Especially, because of the property of flexible members, the flexible coupling can conduct the motion between two shafts and the axial orientations of these two shafts are free of limits i.e., the locations of the two connected shafts could be arbitrary. For the shown design, the utilized flexible member is the spring. The spring is connected to the two shafts in which one of the shafts has the fixed axial orientation, while the other one can arbitrarily adjust its axial orientation by moving along the disk on the frame."

Str_DB[72]=new Array
Str_DB[72][0]="./Page/Model/ntu/J02.Htm"
Str_DB[72][1]="Model: NTU-J02 Double-roller Slot Coupling"
Str_DB[72][2]="Group: Couplings Description: This mechanism comprises of a cross slot and a connecting member with two rollers. It is used for the transmission between two parallel but not colinear shafts. The two-roller connecting member and cross slot are connected to the driving and driven shafts, respectively. When the driving shaft is rotated, the two rollers will periodically roll inside the cross slot back and forth. Accordingly, the driven shaft can be motivated by this rolling contact. However, the rotational speed of the output shaft is shifted from the input shaft by one half, i.e., the output shaft can complete one revolution as the input shaft runs two revolutions. This mechanism can be regarded as one of the linkage mechanisms. The rolling contact between the roller and the slot is merely a degeneration from the slider-crank mechanisms."

Str_DB[73]=new Array
Str_DB[73][0]="./Page/Model/ntu/J03.Htm"
Str_DB[73][1]="Model: NTU-J03 Double-slider Coupling"
Str_DB[73][2]="Group: Couplings Description: This mechanism consists of a pair of sliders and a frame. It is used for the transmission between two parallel but not colinear shafts. The two sliders are connected to the ends of the driving and driven shafts, respectively. When the driving shaft is rotated, the two sliders will slide with respect to each other from which the driven shaft can be motivated. And the rotational speeds of these two shafts are identical."

Str_DB[74]=new Array
Str_DB[74][0]="./Page/Model/ntu/J04.Htm"
Str_DB[74][1]="Model: NTU-J04 Universal Joints"
Str_DB[74][2]="Group: Couplings Description: Universal joint, also known as the universal coupling, Hooke¡¦s joint, or Cardan joint, is a kinematic joint connecting two shafts with intersecting axes. It consists of a driving yoke, a driven yoke, and a cross connecting rod. The driving yoke, driven yoke, and cross connecting rod are connected to each other by revolute joints. And these revolute joints constitute four intersecting axes which are centered at the center of the cross connecting rod. So the universal joint is actually a special case of the spherical four-bar linkages. However, since the transmission ratio of the input shaft and output shaft is not constant, it is usually more practical for application by using two universal joints together, i.e., the double Hooke¡¦s joint. The shown design illustrates the double Hooke¡¦s joint. Two universal joints are connected to the input and output shafts, respectively. Besides, a connecting rod is set to connect these two joints. The location of the output shaft can be adjusted on the arbitrary positions along the arc slot on the frame. Accordingly, the double Hooke¡¦s joints can transmit the motion between two shafts with arbitrary orientations."

Str_DB[75]=new Array
Str_DB[75][0]="./Page/Model/ntu/J05.Htm"
Str_DB[75][1]="Model: NTU-J05 Linkage Coupling"
Str_DB[75][2]="Group: Couplings Description: This coupling is an application of the parallel-crank mechanisms. It consists of three identical parallel-crank mechanisms which share the same cranks. The input and output shafts are connected to the two cranks, respectively. The transmission between the two shafts can therefore be completed through the three parallel linkages. This coupling is used for the transmission between two parallel but not colinear shafts. And, this transmission will be exact, without speed reduction."

Str_DB[76]=new Array
Str_DB[76][0]="./Page/Model/ntu/J06.Htm"
Str_DB[76][1]="Model: NTU-J06 Flange Coupling "
Str_DB[76][2]="Group: Couplings Description: Flange is a rib or rim for strength, for guiding, or for attachment to another object. The flange coupling, therefore, is a coupling that uses the flanges to transmit motion between two shafts. For the shown design, it comprises of a pair of identical flanges and four pins. The two flanges are connected to the input and output shafts, respectively. The pins are designated to mate with the holes on the flanges such that the relative motion between the flanges can be determined. When the pins are inserted into the holes, there are no relative motions between these two flanges. Hence the motion from input shaft can be transferred to the output shaft. Oppositely, when the pins are removed from the holes, the input and output shafts will be disconnected. So the transmission between them will be interrupted."

Str_DB[77]=new Array
Str_DB[77][0]="./Page/Model/ntu/K01.Htm"
Str_DB[77][1]="Model: NTU-K01 Disk-roller Friction Wheels "
Str_DB[77][2]="Group: Friction Drives Description: This mechanism consists of a disk friction wheel, a roller friction wheel, and a frame. It is used for the transmission between two perpendicular but not intersecting shafts with constant transmission ratio. The disk is the driving wheel connecting to the input shaft, while the roller is the driven wheel connecting to the output shaft. When the input shaft rotates, the motion is transmitted to the output shaft through the friction between the disk and roller. Besides, the roller can adjust its position along the diameter of the disk for obtaining different transmission ratio."

Str_DB[78]=new Array
Str_DB[78][0]="./Page/Model/ntu/L01.Htm"
Str_DB[78][1]="Model: NTU-L01 Paddle Wheel Mechanism"
Str_DB[78][2]="Group: Compound Mechanisms Description: This mechanism appears in the water wheel applications and the paddle wheel machines. It primarily consists of three four-bar linkages. Each four-bar linkage has an arm for receiving the input force from the crank and a link for joining a paddle. The orientations of the paddles are controlled by the linkages so that the paddles can ladle water from the bottom to the top."

Str_DB[79]=new Array
Str_DB[79][0]="./Page/Model/ntu/L02.Htm"
Str_DB[79][1]="Model: NTU-L02 Double-eccentric Linkage Mechanism"
Str_DB[79][2]="Group: Compound Mechanisms Description: This mechanism can be treated as a combination and metamorphism of two slider-crank mechanisms. The two cranks are both hinged to the driving link and are connected with two disks, respectively. When the driving link is motivated, each crank will produce an eccentric rotation with respect to the center of its attached disk. Then, the motions caused from the two eccentric rotations are transmitted through the linkages and finally result a reciprocating linear motion to the same slider. Besides, an adjustable four-bar linkage is attached to these two linkages. When the link lengths of the adjustable four-bar linkage are varied, the stroke of the slider will be changed."

Str_DB[80]=new Array
Str_DB[80][0]="./Page/Model/ntu/L03.Htm"
Str_DB[80][1]="Model: NTU-L03 Gear-slider Mechanism"
Str_DB[80][2]="Group: Compound Mechanisms Description: This mechanism comprises of a fan-pinion, a rack, and a frame with slot. The input crank is connected to the fan-pinion and the rack mates with the fan-pinion in forms of the internal gear pair. On the other hand, the rack is also served as a slider that can slide inside the slot on the frame. Hence, when the crank is continuously rotating, the fan-pinion will guide the rack reciprocally translating in the slot."

Str_DB[81]=new Array
Str_DB[81][0]="./Page/Model/ntu/L04.Htm"
Str_DB[81][1]="Model: NTU-L04 Crank-and-rocker Mechanism with a Ratchet"
Str_DB[81][2]="Group: Compound Mechanisms Description: This mechanism is constructed based on a crank-and-rocker mechanism integrated with a ratchet mechanism. First, the crank is the input link with a continuous rotation and the rocker is the output link with a reciprocating oscillation. Meanwhile, the rocker is also the oscillating arm of the ratchet mechanism. It attaches a pawl that can engage with the ratchet. When the rocker is oscillating, the pawl will push the ratchet periodically. Thus the ratchet is motivated with a uni-direction stepping motion. Furthermore, the rocker is also equipped with two adjustable knobs on the circular track. If the distance between the two knobs is adjusted, the stepping length of the ratchet will be changed."

Str_DB[82]=new Array
Str_DB[82][0]="./Page/Model/ntu/L05.Htm"
Str_DB[82][1]="Model: NTU-L05 Gear Transmission with Clutch"
Str_DB[82][2]="Group: Compound Mechanisms Description: This mechanism comprises of several gear sets, including two straight bevel gear pairs and one worm and worm wheel, and a clutch. The clutch is formed by two symmetrical friction wheels and is manipulated by an arm that can be controlled for determining the rotating direction, i.e., counterclockwise or clockwise, of the first bevel gear pair. After the rotating direction of the first bevel gear pairs has been determined, the motion can therefore be inputted from the crank to the gears. Then the transmission will go through the first bevel gear pair, the second bevel gear pair, and the worm and worm wheel. Finally, it outputs a motion at the indicator. Since this mechanism compounds several gear mechanisms and a clutch, it has the functions of variable directions of transmissions and speed reduction."

Str_DB[83]=new Array
Str_DB[83][0]="./Page/Model/ntu/L06.Htm"
Str_DB[83][1]="Model: NTU-L06 Belt-gear-friction Transmission"
Str_DB[83][2]="Group: Compound Mechanisms Description: This mechanism comprises of three major sections: the belt drive, gear transmission, and friction drive. The belt drive consists of a belt, a driving pulley, and a driven pulley with three layers; the gear transmission consists of a gear mechanism with five spur gears; the friction transmission is appeared between the co-axial driven pulley layers and the gears by using the frictions between those and their axis. First, the power is inputted from the crank on the driving pulley. By means of the belt drive, the power is transmitted to the front first layer of the driven pulley. Then, it goes through the gear mechanism and, finally, arrives at the third layer of the driven pulley. Consequently, it concludes the overall transmission. Oppositely, the power transmission can also be started at the third layer of the driven pulley and ended at the first layer. However, the transmission efficiency of the backward operation will be worse than that of the forward operation due to the early appearance of the friction transmission."

Str_DB[84]=new Array
Str_DB[84][0]="./Page/Model/ntu/L07.Htm"
Str_DB[84][1]="Model: NTU-L07 Geared Five-bar Mechanism"
Str_DB[84][2]="Group: Compound Mechanisms Description: The geared five-bar linkage is basically a four-bar mechanism attached with a gear pair. For a general geared five-bar linkage, two links of the four-bar linkage are fixed on the two gears, respectively. Thus the geared five-bar linkages can be regarded as a metamorphism of the four-bar linkages. And, compared to the four-bar linkages, the geared five-bar linkage has the features of better transmission efficiency and superior variability of coupler curves. For the shown mechanism, it is a simple geared five-bar linkage. It comprises of a double-crank mechanism and a spur gear mechanism. The small gear is the input link and the big gear, receiving motion from the small gear, is served as the input crank of the double-crank mechanism. When the small gear is driving, the big gear can make a complete revolution (as a crank), which provided the input rotation of the double-crank mechanism."

Str_DB[85]=new Array
Str_DB[85][0]="./Page/Model/ntu/L08.Htm"
Str_DB[85][1]="Model: NTU-L08 Differential Gear Train with Equal Stepped Pulleys"
Str_DB[85][2]="Group: Compound Mechanisms Description: This mechanism consists of a differential gear train and a couple of the equal stepped pulleys. The stepped pulley is a transmission wheel with stepped shape comprising of a number of wheels with different diameters; the equal stepped pulleys is a belt drive using two identical stepped pulleys. Since the equal stepped pulleys have a set of diameter ratios, they can transmit several different transmission ratios. Besides, if the step number of the pulley is increased to infinite, the surface of the pulley will become as a continuous conical one, and the equal stepped pulleys will transform to a variable speed cone. For the shown mechanism, the transmission is received from the lower pulley, transferred through the belt to the upper pulley, and outputted to the differential gear train. "

Str_DB[86]=new Array
Str_DB[86][0]="./Page/Model/ntu/L09.Htm"
Str_DB[86][1]="Model: NTU-L09 Cycloidal Motion Mechanism"
Str_DB[86][2]="Group: Compound Mechanisms Description: When a circle rolls on the circumference of another circle, each point on the rolling circle can describe a curve, called the cycloidal curve. If the circle rolls outside another circle, the describing curve is an epicycloid; if the circle rolls inside another circle, the describing curve is a hypocycloid. The cycloidal curves are commonly applied in the generation of gear tooth profiles and the design of displacement curves of cam mechanisms. It has the advantages of no interference and undercutting problems for gear design and having smoother acceleration curves, compared with simple harmonic motion curve, for cam design. The shown mechanism is used to demonstrate an application of the cycloidal curves. It consists of a spur gear pair, a connecting rod, a driving crank, and a frame. The internal gear is served as the frame; the external gear is driven by the input crank which is located behind the model; the connecting rod is connected to the external gear on its pitch circle with a revolute joint and is adjacent to the frame with a prismatic joint. Since the radius of the pitch circle of the internal gear is double of that of the external gear, the center of the connecting joint on the pitch circle of the external gear will draw a straight line along the diameter of the pitch circle of the internal gear. Hence, when the external gear is driven, the connecting rod is forced to reciprocally slide on the frame. Since the external gear rolls inside the internal gear, the generating straight line belongs to a hypocycloid."

Str_DB[87]=new Array
Str_DB[87][0]="./Page/Model/ntu/L10.Htm"
Str_DB[87][1]="Model: NTU-L10 Six-bar Straight Line Linkage"
Str_DB[87][2]="Group: Compound Mechanisms Description: Before the planing machine was invented, making a long guide to provide a linear motion was difficult. This provided the incentive to design linkages with only revolute joints that can generate approximate or exact straight lines¡Xsuch linkages are called the straight line mechanisms. Although today¡¦s technology is excellent for manufacturing precise linear guides, the straight line mechanisms are still applicable due to the advantages, compared to the using of linear guides, of lower friction and better precision. For the shown mechanism, it is a straight line mechanism consisting of a six-bar linkage and a spur gear pair. For the spur gears, one gear is fixed on the frame and serves as a sun gear, and the other one is the planet gear that can rotate around the sun gear. For the six-bar linkage, a connecting rod is attached to the planet gear and another someone is constrained inside a sliding slot on the frame. When the planet gear is driven, the connecting rod is motivated and it therefore drives the overall linkage. And the link inside the sliding slot can make an exact straight line motion."

Str_DB[88]=new Array
Str_DB[88][0]="./Page/Model/ntu/L11.Htm"
Str_DB[88][1]="Model: NTU-L11 Eight-bar Straight Line Linkage"
Str_DB[88][2]="Group: Compound Mechanisms Description: It is a straight line mechanism comprising of an eight-bar linkage, including six links, a sliding slot, and a frame. The links are connected together by using the revolute joints only and the sliding slot is connected respectively to the frame with a revolute joint and to a link with prismatic joint. When the input crank, setting in the top of the mechanism, is driven, the link inside the sliding slot can make a reciprocating straight line motion. Because the sliding slot will produce a slight oscillation during operation, the motion of the sliding link is an approximate straight line motion."

Str_DB[89]=new Array
Str_DB[89][0]="./Page/Model/ntu/L12.Htm"
Str_DB[89][1]="Model: NTU-L12 Constant-speed Straight-line Reciprocating Mechanism"
Str_DB[89][2]="Group: Compound Mechanisms Description: This mechanism comprises of two spur gears, a rack and pinion, a slider, and a frame. It is designated to generate a constant-speed reciprocating straight line motion. When the spur gear pair is activated by the input crank, the pinion which is attached to one of the spur gears will push the rack and run around its top and bottom. After, since the rack is attached to the slider, the slider will be pushed with a straight line motion based on the force from the pinion. Because the pinion runs around the top and bottom of the rack, the motion direction of the slider will be guided back and forth, which constitutes a reciprocating motion. Besides, if the crank is driven by a constant speed, the output speed of the slider will also be constant."

Str_DB[90]=new Array
Str_DB[90][0]="./Page/Model/ntu/N01.Htm"
Str_DB[90][1]="Model: NTU-N01 Root's Blower Chamber Wheel Mechanism"
Str_DB[90][2]="Group: Machine Systems Description: This mechanism was first proposed by Root in 1854. When it works, the fluid under the chamber is continuously drawn into the chamber and then rejected through the jet located at the top of the chamber. In the back of the chamber, a pair of spur gears is equipped and connects two particular links with figure eight inside the chamber. When the gear is driven, the two particular links will be rotated with opposite directions. And, based on the specific geometry and mating timing, the fluid under the chamber can be drawn into the chamber and then be jetted out to the chamber. The well-known ancient blowers, for example, are representative for this operation. It continuously blows air through the jet so that plentiful oxygen can be poured into the furnace for increasing the burning temperature."

Str_DB[91]=new Array
Str_DB[91][0]="./Page/Model/ntu/N02.Htm"
Str_DB[91][1]="Model: NTU-N02 Dart's Blower Chamber Wheel Mechanism"
Str_DB[91][2]="Group: Machine Systems Description: This mechanism was invented by Behrens, a partner in the film of Dart and Co. of New York, around 1867. Similar to Root¡¦s blower, this mechanism is used to deliver fluid via the rotating mating wheels in the chamber. Nevertheless, the using wheels in this mechanism are formulated by a semi-circular profile. It makes a surface contact between the mating surfaces of the wheels. So the leakage of the delivering fluid can be kept low. Hence this device can also be used as either a pump or water motor."

Str_DB[92]=new Array
Str_DB[92][0]="./Page/Model/ntu/N03.Htm"
Str_DB[92][1]="Model: NTU-N03 Crane "
Str_DB[92][2]="Group: Machine Systems Description: The crane is an effort-saving device based on the application of gear reducers. The weight is hanged by an iron chain whose end is connected to the lower-speed gear shaft. When the input torque is entered from the higher-speed gear shaft, the torque will be magnified through the gear train. Then, it will be outputted to the lower-speed gear shaft. The shown crane model is manipulated by three control sticks, which are used for lifting weight, turning and braking device, respectively."

Str_DB[93]=new Array
Str_DB[93][0]="./Page/Model/ntu/N04.Htm"
Str_DB[93][1]="Model: NTU-N04 Valve-control Mechanism in Four-stroke Engines"
Str_DB[93][2]="Group: Machine Systems Description: This model illustrates the timing control strategy between the piston and intake valve of the engine. In this engine, the piston is connected to a crank through a connecting rod. The crank is also attached to a gear mechanism in which the tooth numbers of the two gears are different. A pin, which is used to simulate a cam, is set on the big gear to push the bottom link for opening the intake valve. Since the tooth number of the big gear is double of that of the small gear, the intake valve will be opened once while the smaller gear rotates two revolutions (i.e., the piston travels four strokes)."

Str_DB[94]=new Array
Str_DB[94][0]="./Page/Model/ntu/N05.Htm"
Str_DB[94][1]="Model: NTU-N05 Valve-control Mechanism in Horizontal Steam Engines"
Str_DB[94][2]="Group: Machine Systems  Description: This model primarily illustrates the control strategy of the linkage in determining the open and close of the intake valve in a horizontal steam engine. The timing motion of the intake valve in this model is identical to that of the previous horizontal steam engine model. But the movement of the linkage is emphasized in this model. From the back view of the model, the moving process of the linkage in controlling the intake valve of the steam engine can be understood clearly."

Str_DB[95]=new Array
Str_DB[95][0]="./Page/Model/ntut/D01.Htm"
Str_DB[95][1]="Model: NTUT-D01 Toggle Mechanism"
Str_DB[95][2]="Group: Slider-crank Mechanisms Description: For a linkage mechanism, the limit position of a link is the position of a link for which a coordinate which describes its position relative to an adjacent link is a maximum or a minimum. For a mechanism, when one of its links is in a limit position, we said that it is at the limit position of a mechanism. For a four-bar mechanism, if its limit positions are occurred when the active link is aligned with the connecting rod, this mechanism is at the toggle position. When the mechanism is reaching its toggle position, a small input torque can generate an extremely large output torque, where its mechanical advantage is being infinitely maximal. At such situation, the mechanism is called a toggle mechanism. The toggle mechanisms can be used in the situation when one needs to output large force subject to a short stroke, for example, the stone crushers and mechanical presses, etc. The shown mechanism has a toggle position when the two lower links arrange to be aligned. At this position, the slider can produce an extremely large power to press workpiece."

Str_DB[96]=new Array
Str_DB[96][0]="./Page/Model/ntut/E01.Htm"
Str_DB[96][1]="Model: NTUT-E01 Positive Motion Cam Mechanism "
Str_DB[96][2]="Group: Cam Mechanisms Description: For disk cam mechanisms, the motion relationship between cam and follower is not completely determined. It needs some auxiliary forces, e.g., the gravity force or spring force, to avoid the separation between cam and follower during operation. Therefore, the positive motion cam mechanism is the one whose cam can determinately drive the follower, i.e., cam and follower keeps contact during the overall operation, without using auxiliary forces. For the shown models, this cam mechanism has a disk cam whose profile is formed by three equal-radius arcs. Based on this special geometry, its cam and follower can keep contact over the cycle of motion."

Str_DB[97]=new Array
Str_DB[97][0]="./Page/Model/ntut/F01.Htm"
Str_DB[97][1]="Model: NTUT-F01 Crossed Helical Gear Mechanism"
Str_DB[97][2]="Group: Gear Mechanisms Description: This mechanism demonstrates the transmission of a crossed helical gear pair. The crossed helical gear pair comprises of two matching helical gears with crossed axes. It can transmit the motion between two crossed axes."

Str_DB[98]=new Array
Str_DB[98][0]="./Page/Model/ntut/F02.Htm"
Str_DB[98][1]="Model: NTUT-F02 Hyperboloid Gear Mechanism"
Str_DB[98][2]="Group: Gear Mechanisms Description: This mechanism demonstrates the transmission of a hyperboloid gear pair. A hyperboloid of revolution is the surface developed by a straight-line generatrix, tangent to a base cylinder and at an angle to the axis of the base cylinder, as it is revolved about the axis of the base cylinder. The hyperboloid gear is generated based on formulating the straight-line, which is used to generate a hyperboloid of revolution, as its tooth profile. The hyperboloid gear pair is equivalent to a rolling and sliding contact between two hyperboloids. It can transmit the motion between two crossed axes. However, since the contact of two meshing hyperboloid gears is a line contact, there will be a slipping motion along the tooth profile of the hyperboloid gears when transmission. Thus the transmission of hyperboloid gears has the problem of greater frictions."

Str_DB[99]=new Array
Str_DB[99][0]="./Page/Model/ntut/F03.Htm"
Str_DB[99][1]="Model: NTUT-F03 Epicyclic Gear Train (1)"
Str_DB[99][2]="Group: Gear Mechanisms Description: The epicyclic gear train, also called the planetary gear train, is derived from appropriate combination of two or more gears and at least one gear axis is rotated about another gear axis. As shown in the figure, this epicyclic gear train comprises of three gears, where the central gear is called the sun gear, the outmost gear is called the ring gear, the gear between sun gear and ring gear is the planet gear, and the sun gear and planet gear are connected by the element called the arm. The axis of the sun gear and the ring gear are grounded. The planet gear can revolve on its own axis and have a revolution around the sun gear. So this mechanism has two degrees of freedom."

Str_DB[100]=new Array
Str_DB[100][0]="./Page/Model/ntut/F04.Htm"
Str_DB[100][1]="Model: NTUT-F04 Epicyclic Gear Train (2)"
Str_DB[100][2]="Group: Gear Mechanisms Description: This is a simple epicyclic gear train with one sun gear, two planet gears, and one arm. The sun gear is served as the frame and the arm connecting two planet gears is served as the input link. When the arm is driven, the two planet gears will revolve round the sun gear."

Str_DB[101]=new Array
Str_DB[101][0]="./Page/Model/ntut/F05.Htm"
Str_DB[101][1]="Model: NTUT-F05 Epicyclic Gear Train (3)"
Str_DB[101][2]="Group: Gear Mechanisms Description: This epicyclic gear train consists of one sun gear, three planet gears, one ring gear, and an arm. The sun gear is served as the frame and the arm is the input link. This mechanism has one degree-of-freedom. "

Str_DB[102]=new Array
Str_DB[102][0]="./Page/Model/ntut/F06.Htm"
Str_DB[102][1]="Model: NTUT-F06 Differential Gear Train and Spur Gears"
Str_DB[102][2]="Group: Gear Mechanisms Description: This mechanism comprises of three bevel gears and two spur gears. The bevel gear near to the input crank is served as the frame and the other gears are all movable. When inputting a rotation from the crank, the bigger spur gear will be rotated and the middle bevel gear whose axis is set on the circle of the wheel of the bigger spur gear will rotate about its own axis and revolve about the axis of input crank. Besides, the smaller spur gear will be driven by the bigger spur gear."

Str_DB[103]=new Array
Str_DB[103][0]="./Page/Model/ntut/F07.Htm"
Str_DB[103][1]="Model: NTUT-F07 Gear Transmission"
Str_DB[103][2]="Group: Gear Mechanisms Description: This mechanism illustrates a transmission in a set of gear mechanisms. It includes the spur gears, lantern gear and crown gear, straight bevel gear pairs, worm and worm wheel. The lantern gear is a gear of which the gear teeth are cylindrical cogs with axes parallel to the gear axis. And, the crown gear is a bevel gear with a reference cone angle of 90 degree."

Str_DB[104]=new Array
Str_DB[104][0]="./Page/Model/ntut/I01.Htm"
Str_DB[104][1]="Model: NTUT-I01 Screw Press"
Str_DB[104][2]="Group: Screw Mechanisms Description: One of the typical applications of screw mechanisms is the effort-saving devices. And the screw presses are a representative application of effort-saving devices. The fundamental principle of the screw presses is, via the screw motion, to convert a small input torque as an extremely large output force. For the shown design, this screw press is constructed with a screw and a frame. On the lower end of the screw, a press plate is attached to the screw and the workpiece can be placed under the press plate to wait for pressing. When a torque is inputted into the screw, the screw will output a translational motion, which forces the press plate pressing the workpiece in a very large force."

Str_DB[105]=new Array
Str_DB[105][0]="./Page/Model/ntut/J01.Htm"
Str_DB[105][1]="Model: NTUT-J01 Oldham Coupling"
Str_DB[105][2]="Group: Couplings Description: Oldham coupling is used for the transmission between two parallel but not colinear shafts. It comprises of a pair of components which have the key slots and a connecting member which has the keys. The two key-slot components are connected to the driving and driven shafts, respectively. The connecting member is set between the two components by mating the keys on the connecting member with the key slots on the components. When the driving shaft is rotating, the connecting member will slide on the key slots back and forth. And the driven shaft is motivated with the same rotational speed as that of the driving shaft. However, since all members of the Oldham coupling are with pure sliding motion with respect to each other, this coupling has the wear problem."

Str_DB[106]=new Array
Str_DB[106][0]="./Page/Model/ntut/J02.Htm"
Str_DB[106][1]="Model: NTUT-J02 Linkage Coupling"
Str_DB[106][2]="Group: Couplings Description: This coupling is an application of the parallel-crank mechanisms. It consists of three identical parallel-crank mechanisms which share the same cranks. The input and output shafts are connected to the two cranks, respectively. The transmission between the two shafts can therefore be completed through the three parallel linkages. This coupling is used for the transmission between two parallel but not colinear shafts. And, this transmission will be exact, without speed reduction."

Str_DB[107]=new Array
Str_DB[107][0]="./Page/Model/ntut/L01.Htm"
Str_DB[107][1]="Model: NTUT-L01 Gear-slider Mechanism"
Str_DB[107][2]="Group: Compound Mechanisms Description: This mechanism comprises of a fan-pinion, a rack, and a frame with slot. The input crank is connected to the fan-pinion and the rack mates with the fan-pinion in forms of the internal gear pair. On the other hand, the rack is also served as a slider that can slide inside the slot on the frame. Hence, when the crank is continuously rotating, the fan-pinion will guide the rack reciprocally translating in the slot."

Str_DB[108]=new Array
Str_DB[108][0]="./Page/Model/ntut/L02.Htm"
Str_DB[108][1]="Model: NTUT-L02 Cycloidal Linear-motion Mechanism"
Str_DB[108][2]="Group: Compound Mechanisms Description: When a circle rolls on the circumference of another circle, each point on the rolling circle can describe a curve, called the cycloidal curve. If the circle rolls outside another circle, the describing curve is an epicycloid; if the circle rolls inside another circle, the describing curve is a hypocycloid. The cycloidal curves are commonly applied in the generation of gear tooth profiles and the design of displacement curves of cam mechanisms. It has the advantages of no interference and undercutting problems for gear design and having smoother acceleration curves, compared with simple harmonic motion curve, for cam design. The shown mechanism is used to demonstrate an application of the cycloidal curves. It consists of a spur gear pair, a connecting rod, a driving crank, and a frame. The internal gear is served as the frame; the external gear is driven by the input crank which is located behind the model; the connecting rod is connected to the external gear on its pitch circle with a revolute joint and is adjacent to the frame with a prismatic joint. Since the radius of the pitch circle of the internal gear is double of that of the external gear, the center of the connecting joint on the pitch circle of the external gear will draw a straight line along the diameter of the pitch circle of the internal gear. Hence, when the external gear is driven, the connecting rod is forced to reciprocally slide on the frame. Since the external gear rolls inside the internal gear, the generating straight line belongs to a hypocycloid."

Str_DB[109]=new Array
Str_DB[109][0]="./Page/Model/ntut/L03.Htm"
Str_DB[109][1]="Model: NTUT-L03 Six-bar Straight Line Linkage"
Str_DB[109][2]="Group: Compound Mechanisms Description: Before the planing machine was invented, making a long guide to provide a linear motion was difficult. This provided the incentive to design linkages with only revolute joints that can generate approximate or exact straight lines¡Xsuch linkages are called the straight line mechanisms. Although today¡¦s technology is excellent for manufacturing precise linear guides, the straight line mechanisms are still applicable due to the advantages, compared to the using of linear guides, of lower friction and better precision. For the shown mechanism, it is a straight line mechanism consisting of a six-bar linkage and a spur gear pair. For the spur gears, one gear is fixed on the frame and serves as a sun gear, and the other one is the planet gear that can rotate around the sun gear. For the six-bar linkage, a connecting rod is attached to the planet gear and another someone is constrained inside a sliding slot on the frame. When the planet gear is driven, the connecting rod is motivated and it therefore drives the overall linkage. And the link inside the sliding slot can make an exact straight line motion."

Str_DB[110]=new Array
Str_DB[110][0]="./Page/Model/ntut/L04.Htm"
Str_DB[110][1]="Model: NTUT-L04 Constant-speed Reciprocating Straight Line Mechanism"
Str_DB[110][2]="Group: Compound Mechanisms Description: This mechanism comprises of two spur gears, a rack and pinion, a slider, and a frame. It is designated to generate a constant-speed reciprocating straight line motion. When the spur gear pair is activated by the input crank, the pinion which is attached to one of the spur gears will push the rack and run around its top and bottom. After, since the rack is attached to the slider, the slider will be pushed with a straight line motion based on the force from the pinion. Because the pinion runs around the top and bottom of the rack, the motion direction of the slider will be guided back and forth, which constitutes a reciprocating motion. Besides, if the crank is driven by a constant speed, the output speed of the slider will also be constant."

Str_DB[111]=new Array
Str_DB[111][0]="./Page/Model/ntut/N01.Htm"
Str_DB[111][1]="Model: NTUT-N01 Valve-control Mechanism in Horizontal Steam Engines"
Str_DB[111][2]="Group: Machine Systems Description: This model primarily illustrates the control strategy of the linkage in determining the open and close of the intake valve in a horizontal steam engine. The timing motion of the intake valve in this model is identical to that of the previous horizontal steam engine model. But the movement of the linkage is emphasized in this model. From the back view of the model, the moving process of the linkage in controlling the intake valve of the steam engine can be understood clearly."

Str_DB[112]=new Array
Str_DB[112][0]="./Page/Model/ntut/.Htm"
Str_DB[112][1]=""
Str_DB[112][2]=""

Str_DB[113]=new Array
Str_DB[113][0]="./Page/Model/ntut/.Htm"
Str_DB[113][1]=""
Str_DB[113][2]=""