| 摘要 |
<p>618,243. Fluid-pressure-operated brakes. DUNLOP RUBBER CO., Ltd., and TREVASKIS, H. Dec. 22, 1945, No. 34841. [Class 103 (i)] [Also in Group XXXVII] The fluid-pressure in a brake-operating chamber is regulated in accordance with the setting of a control member, by means of electromagnetically operated supply and exhaust valves the circuits of which are controlled by contacts movable by the control member in co-operation with a piston subject to the pressure in the chamber acting against a spring. The system shown is suitable for the landing wheel brakes of aircraft and comprises a relay valve device 7 as described in Specification 560,201, supplying brake operating means 22. The windings of supply and exhaust valves 8, 9 are connected to contacts 12a, 12b carried by a block 15 slidable in a casing 13 and connected by a link 16 to a lever 17 actuated by the operator. A conducting disc 14 is acted on by an eccentrically arranged spring 19 which serves also to connect the disc to the current source 19. A piston 13c in the casing 13 subject by pipe 21a to the pressure in the operating chamber of the brake 22 is urged downwards by a spring 25 and carries a rod 24 engaging the disc 14. Normally the disc 14 being separated from the contacts 12a, 12b, as in Fig. 1, so that the valves 8, 9 are deenergized, the valve 9 is open and the valve 8 is closed. The supply and exhaust valves 7d, 7e are thus respectively closed and open. If the block 15 is moved upwards to a limited extent by lever 17 both valves 8, 9 are energized by the disc 14 seating on the inturned ends of the contacts 12a, 12b and are thus opened and closed respectively. Pressure fluid is supplied from the reservoir 5 by pipes 6a, 11 to the chamber 7b of the relay valve, whereby the valve 7d is opened to supply the brake-operating chamber 22 the pressure in which acting on the piston 13c moves the piston upwards to engage the disc 14. Due to the eccentric arrangement of the spring 18 the disc tilts as shown in Fig. 4, thus de-energizing the valve 8 . and cutting-off the fluid supply to the brake-operating chamber 22 and the piston 13c. To release the brake the block 15 is moved downwards to return the plate to the horizontal position so that the valve 9 as well as the valve 8 is de-energized. The block 15 may be arranged for operation by the steering gear of an aircraft or vehicle for differential braking.</p> |
