Pneumatic weight lift assist apparatus

Claim 1

A weight lifting assist apparatus, for use with a weight machine of the type having a cable operably extending through a series of pulleys to a handle, comprising: a hollow upright cylinder having upper and lower ends; a piston operably mounted within said cylinder for reciprocal vertical movement; said piston having an outer diameter smaller than the inner diameter of the cylinder, to form an annular space therebetween which permits leakage of fluid past the piston; the upper end of said cylinder having an opening formed therein through which said weight machine cable will extend for connection to said piston, said opening permitting the entrance of fluid into said cylinder above said piston; means connected to said cylinder for selectively producing vacuum pressure in said cylinder below said piston, to place a downward force on said piston and apply a force to said cable; means connected to said vacuum pressure producing means for selectively varying the vacuum pressure in the cylinder, and thereby vary the force applied to the cable; and said vacuum pressure producing means including a port in said cylinder below said piston for the passage of fluid out of the cylinder.