US Patent 7503881 Exercise apparatus with weight stacks and elastic bands

An exercise machine with a bench press and a pair of weight stacks, which are operationally connected to a lifting bar of a barbell. Pushing motion on the lifting bar transmits the force to a series of wheels connected by flexible bands and to a pair of weight stacks positioned behind the bench press. The weight members of the weight stack are connected by pins, such that upward movement of the uppermost weight members causes pulling force to be applied to successive lower weight members one at a time, thereby allowing incremental increase in the resistance force to the lifting motion of the user.