Length adjustment device

A length adjusting device comprising first means defining a first point, second means defining a second point, said first point and said second point being movable with respect to each other between a first fixed distance and a second variable distance, a first longitudinally extending member pivotably connected to said first means, a second longitudinally extending member pivotably connected to said second means, said first and second longitudinally extending members being pivotably connected to each other at a predetermined pivot point, said first longitudinally extending member including thread means offset from said pivot point, and adjusting screw means adjustably threaded with said thread means, said adjusting screw means including a first end and a second end comprising a protruding member whereby said second end of said adjusting screw means projects from said first longitudinally extending member when said adjusting screw means is adjustably threaded with said thread means by a predetermined alterable distance, said second longitudinally extending member including an interacting surface comprising a recessed portion for interacting with said protruding member at said predetermined alterable distance whereby said second end of said adjusting screw means projects from said first longitudinally extending member and determines said first fixed distance between said first and second means.