Weight lifting machine

Claim 1

In a weight lifting machine having an upright frame including a pair of elongated generally upright laterally spaced weight guide members pivoted at their lower ends to the frame, a stack of discrete graduated weights supported on the guide members adjacent their lower ends, the weight guide members extending through the stack of weights at horizontally spaced locations thereon, each of the weights being slidable on the guide members, an elongated generally upright selector member, the lower end portion of the selector member extending slidably through the weight stack at a location between the guide members therethrough, the selector member including a plurality of transverse apertures spaced longitudinally thereof at locations corresponding to locations between adjacent ones of the weights, means insertable between an adjacent pair of the weights and through the selector member aperture therebetween in order to provide a selected one or ones of the weights, the selector member and the weights so selected being liftable relative to the guide members and the non-selected weights of the stack, and a generally horizontal lifting member having an end pivoted to the frame and having means at another end for lifting movement of the lifting member by the limb or limbs of a trainee, the lifting member being pivoted intermediate its ends to the upper end of the selector member, whereby lifting movement of the lifting member causes pivoting movement of the guide members and the weight stack about said guide member lower end pivots, the improvement comprising: at least one spring assembly carried by the frame including at least one unwindable and self-winding spring of the non-cumulative forced type having a free end, unwinding of the spring by its free end being resisted by a pre-determined constant tension throughout substantially all said unwinding, the spring being generally horizontally offset from the selector member and weight stack, a flexible member connected at one end to said spring end, the flexible member passing over pulley means disposed beneath the lower end of the selector member and having its other end releasably connected to the lower end of the selector member effective to unwind the spring against said tension upon lifting of the selector member and said selected weights by the lifting member as aforesaid.