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.