GB570958A - New or improved device to control the degree of circumferential slip of a frictionaldrive or driven wheel, and or control the maximum speed of the driver - Google Patents

Abstract

570,958. Friction drives ; regulating slip. BURNAND, J. W. March 20, 1943, No. 4561. [Class 80 (ii)] [Also in Group XXXI] Means for preventing slip of driving wheels on a motor-vehicle, or between driving and driven members of shafts coupled by a friction clutch or belt, and also for limiting the maximum speed of the driving wheels or driven shaft, comprise a pump coupled to the driving member, a second pump coupled to the driven member, and a control member actuated by the two pumps in such a manner as to reduce the power supply to the driving member when the latter overruns the driven member in consequence of slip in the friction clutch &c., a constriction being provided in the pump circuit to limit the speed. In the construction shown applied to a vehicle a pump A driven by the drive to the vehicle driving wheels W<1>, W<2> has its delivery side connected to a cylinder C, and pumps B, B<1> driven by non-driving wheels W<3>, W<4> have their suction sides connected to the cylinder C, the other sides of the three pumps being connected to a tank D. Under normal running conditions the pumps B, B<1> take away the liquid supplied by pump A, but if the wheels W<1>, W<2> slip the speed of pump A increases, pressure builds up in cylinder C and a piston C<1> therein is forced outwards and closes the engine throttle H. A leak E allows the piston C<1> to return when slip stops, and a non-return valve F allows liquid to pass to make up any loss. A constriction G is provided in the pipe leading to the pumps B, B<1> so as to cause pressure to build up behind the piston C', if the speed becomes too high, and thus slow down the engine. Instead of the two pumps B, B<1>, a single pump driven from the wheels W<3>, W4 through a differential gear may be used. The inward movement of the piston C<1> beyond the position needed to open the throttle may be caused to reduce the braking power on the driving wheels, or alternatively, a separate cylinder and piston may be used. The capacity of the pump A may be, say, 10 per cent less than that of the combined pumps B, B<1> so that a certain amount of slip would take place before the piston C<1> closes the throttle. The Provisional Specification states also that the friction drive between shafts may be a friction disc and wheel.