Compute the forces at the pins A B and C and the force F as

Compute the forces at the pins A, B and C and the force F as a function of the design parameter x. What value of x should be used to cause F = 250 N?

Solution

Point A acts as the lever for the applied force of 250 N.

The force acting at point F is a result of a couple produced by the applied force of 250 N.

The forces should be proportional to the force F at the tool tip,

Fb / F = (80 + x) / 40

Fc / F = (80 + x) / (40 + x)

Fa / F = (80 + x) / 200

The couple about point A is given by,

F * ( 40 + 40 + x) = 250 * 200

F * (80 + x) = 250 * 200

If, F has to be 2500 N, the above eqn has x to be,

x = 250 * 200 / F - 80

x = 120 mm