Patent ID: 8287251

Claim:
In a hand operated hydraulic pump having a lever, the lever including a handle and a pivot, the pump including a pumping unit with a plunger that engages the lever between the handle and the pivot, the handle being operable to reciprocate the plunger so as to pump hydraulic fluid as the lever is pivoted back and forth, the improvement wherein: the pivot of the lever is pivoted to a cam at a lever pivot; the cam is pivoted to a frame of the pump at a frame pivot, the frame pivot on the cam being spaced away from the lever pivot such that pivoting the cam about the frame pivot changes the distance between the lever pivot and the plunger of the pumping unit; and a compensation device that is subjected to the output pressure of the pump and slidingly engages the cam so as to rotate the cam about the frame pivot in relation to the output pressure of the pump so as to reduce the distance between the lever pivot and the plunger of the pumping unit as the output pressure increases.