Links 2 and 3 are designed as cams with working surfaces a-a. The lengths of the links comply with the conditions: A͞F=B͞E and F͞D=E͞D. Thus the upper half of the mechanism is symmetrical to the lower half, thereby ensuring uniform distribution of force P, applied at point C, over the kinematic pairs. When link is pulled toward the left, levers 2 and 3 turn about points A and B, and grip the end of wire 4 with the profiled surfaces a-a.
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