GB252380A - - Google Patents

Abstract

252,380. Bonnebeau, R., and Bonnebeau, G. May 19, 1925, [Convention date]. Fluid - pressure. - In vacuum brakes operated for instance by the suction of the driving engine of the vehicle &c. and in which the co-operating members of the control valve are carried by the piston and ,connected to the brake pedal respectively so that a graduated action of the. brake is obtained corresponding to the extent of movement of the pedal, the control valve comprises a slide valve and a lift valve controlling the suction passage and the air inlet respectively. The slide valve member 17 is connected to the pedal by a rod 18 disposed in a tubular rod 6 extending from the piston 5, and is normally held by a spring 20 in the position shown in which it closes a passage 14 in the piston and holds open a lift valve 21 whereby the space 1<a> of the cylinder 1 is open to atmosphere by passage 15 and orifices 11 in the end plate 9 of the piston, which is connected by the rod 12 to the brakes. The passage 14 is connected by the cavity 13 in the piston and the orifice 4 to the suction pipe of the engine. To apply the brake, the rod 18 is moved upwardly by the pedal whereby the valve 21 closes and the passage 14 is uncovered so that a partial vacuum is established in the cylinder space 1<a>. The consequent movement of the piston recloses the passage 14. Further movement of the pedal is followed by further movement, of the, brake and thus the application of the brake can be graduated. Similarly the brake can be progressively released, the release movement of the pedal causing the. valve 21 to be opened and the consequent return movement of the piston effecting its closure. The piston can be directly operated, in the event of failure of the vacuum, by the engagement of a. shoulder 19 on the rod 18 with the plug 7 on the rod 6.