Hydrostatic conveyor drive
First Claim
1. In a conveyor drive system having a master drive for driving the conveyor at a constant speed independent of conveyor load, a slave drive system connected to said conveyor independently of said master drive for moving said conveyor in the same direction, said slave drive system including a closed circuit hydrostatic drive having a variable displacement pump delivering fluid in a supply line to a fixed displacement motor, control means for varying the displacement of said pump including a control member movable in one direction to increase the displacement and in the other direction to decrease the displacement of said pump, first means biasing said control member in said one direction with a uniform force, and second means connected to said control member to move the latter in said other direction to decrease the displacement of said pump and the speed of said motor in proportion to the pressure in said supply line.
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Accused Products
Abstract
A conveyor drive system employing a constant speed master drive and a slave drive of the hydrostatic, closed loop type in which there are no electrical or hydraulic feedback lines between the master and slave drive unit. The master drive moves the conveyor at a constant speed as load varies and the slave drive unit responds to changes in load on the conveyor to vary the speed of the drive to maintain a constant pull on the conveyor to insure that the slave drive shares its portion of the load with the master drive.
13 Citations
18 Claims
- 1. In a conveyor drive system having a master drive for driving the conveyor at a constant speed independent of conveyor load, a slave drive system connected to said conveyor independently of said master drive for moving said conveyor in the same direction, said slave drive system including a closed circuit hydrostatic drive having a variable displacement pump delivering fluid in a supply line to a fixed displacement motor, control means for varying the displacement of said pump including a control member movable in one direction to increase the displacement and in the other direction to decrease the displacement of said pump, first means biasing said control member in said one direction with a uniform force, and second means connected to said control member to move the latter in said other direction to decrease the displacement of said pump and the speed of said motor in proportion to the pressure in said supply line.
- 12. A conveyor drive system for maintaining a constant pull on a conveyor independently of load on the conveyor comprising, a closed circuit hydrostatic drive having a variable displacement pump, a fixed displacement motor connected to the conveyor, a supply line for delivering hydraulic fluid from said pump to said motor, a return line for delivering hydraulic fluid from said motor to said pump, control means movable to vary the displacement of said pump, actuating means connected to said control means to move the latter in proportion to the pressure in said supply line to vary the delivery of hydraulic fluid from said pump to said motor to vary the speed of said motor, said actuating means comprising a hydraulic cylinder, means biasing said cylinder in one direction with a constant force, and a fluid conduit communicating said cylinder with said supply line for moving said cylinder in the other direction in response to pressure in said supply line.
Specification