Hand power tool mechanism

Claim 1

A hand power mechanism to be actuated by the fingers of the human hand for a tool of a type which is designed to be used with the hand oriented so that the index finger is closest to the tool and the little finger is farthest away from the tool, the hand power mechanism comprising a stationary handle (101) for fixed attachment to the tool having a surface to be engaged during use by the palm of the hand; a drive lever (102) pivotally attached to said stationary handle at a first pivot location (103); a movable handle (104) having a surface with locations to be engaged during use by the index, middle, ring and little fingers of the hand, said movable handle being pivotally connected to said drive lever at a second pivot location (105); a linkage closure bar (106) pivotally connected to said stationary handle and to said movable handle at third (108) and fourth (107) pivot locations, respectively, spaced from said first and second pivot locations, respectively, so that said linkage closure bar and said drive lever form a four-bar linkage with sections of said stationary handle and said movable handle between said pivot locations, said first, second, third and fourth pivot locations being arranged so that when said movable handle is moved by the hand toward said stationary handle, the distance traveled by the index finger of said hand is greater than the distance traveled by the little finger of said hand, thereby providing an optimal force/travel ratio for said fingers.