GB358126A - Improvements in hydraulic brakes - Google Patents

Abstract

358,126. Fluid - pressure brakes. HALL, F. H., Cleeve Cottage, Holford, near Bridgwater, Somerset. April 9, 1931, No. 17771/30. [Class 103 (i).] Hydraulic or fluid-pressure brakes, particularly for motor vehicles provided with means comprising a valve 6 carried by a piston 5 in a cylinder 1 for adjusting the brakes which will allow the necessary quantity of fluid to apply the brakes to pass from the pedal-operated master cylinder to the wheel cylinders but controls the return of fluid to the master cylinder is constructed to allow of the grinding in of the valve. The stem of the valve 6 is provided with a slot 7a and a removable screw plug 27 is provided to allow of the insertion of a screwdriver whereby the valve can be ground upon its seating. The piston 8 is adjustably fixed on the valve 6 in order to regulate the quantity of fluid returned to the master cylinder. Fluid is adapted to be forced by the master cylinder through a union 4 which fluid forces the valve 6 off its seating and entering the cylinder 1 raises the piston 8. The piston forces fluid on the upper side of the piston through unions 13 to the front and rear wheel brake cylinders in order to apply the brakes until the piston abuts against a screw plug 27 at the top of the cylinder 1 when the lowest groove of three grooves 23 formed by vertical grooves 26 is uncovered by the piston 1 and the master cylinder is placed in direct communication with the wheel cylinders. Fluid flows from the master cylinder to the wheel cylinders if through wear the brake shoes are not fully applied. When the pressure on the brake pedal of the master cylinder is relieved the piston. 8 descends and closes the groove 23 interrupting the direct connection between the master and the wheel cylinders and the valve 6 is closed, preventing leakage of fluid past the piston. An air-release plug 30 is provided in the plug 27. In a modification a separate cylinder 1 is screwed directly to each wheel brake cylinder, the piston is fixed on the valve stem and the valve seat is adjustable.