GB243588A - Improvements in or relating to fluid pressure operated brake mechanism for motor vehicles - Google Patents

Abstract

243,588. Godeau, F. L. March 3, 1925. Fluid-pressure.-The pedal operating the lever brake mechanism of motor-vehicle brakes is adapted, in its initial movement, to operate a hollow slide valve controlling a pressure fluid brake, the arrangement being such that a graduated application and release of the brakes may be obtained. The pedal 1, Fig. 1, actuates the brake lever 10 through a spring 28, and a link 5 thereon actuates an arm 4 pivoted on a lever 2 and connected, by a rod 8 to the hollow slide valve 11 of the pressure-fluid brake, which comprises a gear pump 16, driven from the lay shaft of the gear box or otherwise, and adapted to force oil from a tank 15 through a passage 33 to the slide valve chamber 12. With the slide valve 11 in valve chamber 12. With the slide valve 11 in the release position shown, the oil is returned to the tank by the passages 17. 20, 22, but when in a brake application, the slide valve is moved to the left, the passages 20, 22 are thrown out of register, and the passage 19 registers with the passage 23 so that the brake cylinder 13 is supplied with fluid and the piston 14 moves out to add pressure to the brakes through rods 24, 25, the lever 2, rod 9, and lever 10. The movement of the lever 2 rocks the arm 4 to move the slide valve to a mid position in which all its passages are blanked, the oil pumped into the passage 33 being then returned to the tank through a valve 30. By repeatedly operating the slide valve to connect the passages 19, 23 and allowing the resulting movements of the lever 2 to return it to mid position, the driver may develop the braking effort gradually. When the driver releases the pedal, the slide valve returns to release position so thar the brake cylinder exhausts through passages 18, 21, and tho oil again circulates through the passages 33. 17, 20, and 22. The movement of the peda,l necessary to operate the slide valve brings an adjustable stop 6 into contact with the lever 2, so that if the pressure brake fails to act, the continued movement of the pedal will apply the brakes directly both through the spring 28 and the lever 2, the rod 25 then sliding over the rod 24. Fig. 4 shows an arrangement wherein the movement of the pedal is opposed by pressure transmitted from the cylinder 13 to a sleeve cylinder 34 in which works a piston 35 connected to the pedal by a rod 36. The pressure exerted on the sleeve cylinder is transmitted to the tail rod C of the piston 14 by means of a rod A and lever B.