| 摘要 |
310,027. Servo-Frein Dewandre, (Assignees of Gauch, A. G.). April 21, 1928, [Convention, date]. Fluid-pressure.-In a brake actuated by pneumatic pressure under the control of a pedal connected to the mechanical transmission system of the brakes, the effort exerted on the pedal is transmitted hydraulically or pneumatically to a distributor which controls the communication of the brake-operating cylinder with the source of compressed air or vacuum and the atmosphere. As applied to a compressed air system, the pedal lever 1 mounted on the brake-operating shaft 2 and connected to the piston 16 carries in a casing 3 a series of deformable chambers 4 engaged by the slidable rod 6 of a pedal plate 2. The chambers 4 are connected by tubing 8, 9, 10 to a second series of deformable chambers 11 connected to a rod 18 subject to the action of a spring 19 and carrying arms 20, 21 adapted to engage the rods of valves 22, 23 which control communication of the brake cylinder 15 with a source of compressed air and with the atmosphere respectively. The chambers 11 are disposed in a chamber 13 which is open to the brake cylinder. When pressure is applied to the plate 7, the brakes are applied mechanically through the lever 1, and the simultaneous compression of the chambers 4 increases the pressure within the chambers 11, and when this pressure is sufficient to overcome the pressure of the spring 19 the exhaust valve 23 is closed and the supply valve 22 opened. When the pressure thus established in cylinder 15 and chamber 13 together with that of the spring 19 exceeds the pressure within the chambers 11, these chambers contract, permitting the closure of the valve 22 while the valve 23 remains closed. The pressure applied to the brakes may be graduated as desired by varying the pressure applied to the plate 7. An initial pressure may' be established in the chambers 4, 11. In a modified construction for a vacuum system, the pressure exerted to apply the brakes acts as a pull on a rod connected to chambers such as 4 which are thereby extended and thus create a vacuum in chambers such as 11 which are connected to a slide valve controlling the connection of the brake cylinder to the source of vacuum and atmosphere. |
