operation of the fork lift only to the extend needed to displace hydraulic fluid into or out of the 34 counterweighted 34 actuator in some cases such displacement will call for expending energy to add to or substract from the counterweight action in other cases the necessary fluid displacement results in an energy return to the system i e in restoring energy to the battery application_number US 2618187 A description the invention will be illustratively described for a preferred embodiment in conjunction with the accompanying drawings in said drawings fig1 is a simplified and partly broken away view in perspective of a fork lift vehicle embodying the invention and fig2 is a schematic diagram of circuitry involved in lift mechanism of the vehicle of fig1 in the four wheeled fork lift vehicle 10 of fig1 a chassis 11 rigidly supports upstanding frame members 12 having overhead interconnection 13 and providing rigid substantially vertical parallel alignment of spaced guides 14 for a lift slide 15 lifting fork arms 16 extend horizontally forward and are rigid with the lower end of slide 15 hoist mechanism for up down positioning of slide 15 is shown to comprise a single acting hydraulic thrusting cylinder 17 secured by means not shown to chassis 11 and having a cable sheave 18 at the projecting upper end of its piston rod 19 a lift cable 21 is tied at one end to cylinder 17 and therefore to the frame it has a first course a upward to and around sheave 18 and a second course b downward to the point of suspending connection to slide 15 cable 21 will be understood as a simplified schematic showing of a sprocket chain floor.