초록 ▼

A drive system useful for driving reciprocating equipment such as saw mill log carriages or the like is disclosed. The drive system includes a plurality of fixed displacement pumps driven by a prime mover. The pumps in turn drive one or more fixed displacement hydraulic motors which drive the carria

A drive system useful for driving reciprocating equipment such as saw mill log carriages or the like is disclosed. The drive system includes a plurality of fixed displacement pumps driven by a prime mover. The pumps in turn drive one or more fixed displacement hydraulic motors which drive the carriage. The pumps are provided with pressure responsive unloading valves which unload at different pressures so that as pressure on the system builds up one or more pumps are sequentially unloaded. An accumulator is charged at low pressures and provides fluid for driving the motors when required at the higher pressures. The inertial forces in the heavy carriage, during the time when the carriage is slowing down, are used to drive the fixed displacement motors as pumps. During this portion of the cycle, the motors are interconnected with the accumulator so that the pumping action of the motors is used to recharge the accumulator.

대표청구항 ▼

A hydraulic drive system for a reciprocating carriage comprising fixed displacement pump means, reversible hydraulic motor means having first and second fluid passages, a fluid supply conduit means for delivery of fluid under pressure from the pump means to the motor mean, control valve means movabl

A hydraulic drive system for a reciprocating carriage comprising fixed displacement pump means, reversible hydraulic motor means having first and second fluid passages, a fluid supply conduit means for delivery of fluid under pressure from the pump means to the motor mean, control valve means movable to a first position for connecting the conduit means to the first of said passages and for connecting the second passage to a reservoir of fluid, said control valve means being movable to a second position for connecting the conduit means to the second passage and for connecting the first passage to the reservoir, a drive connection between the motor means and the carriage, a hydraulic accumulator connected to said conduit means, accumulator valve means for discharge of fluid under pressure from the accumulator to the conduit means in response to load pressures in said conduit means in excess of a predetermined value, and means for recharge of said accumulator, means including said drive connection, whereby the inertial forces on the carriage drive said motor means as a pump to deliver operating fluid under pressure to said accumulator for use during other portions of an operating cycle, said accumulator recharge means being operative following movement of the control valve means from one of said positions to the other position after said carriage has attained a desired carriage velocity.