| 摘要 |
<p>799,817. Controlling clutches and brakes. CLARK EQUIPMENT CO. Dec. 10, 1956 [Dec. 15, 1955], No. 37626/56. Class 80 (2). A valve for use in an industrial truck having pressure fluid engaged reverse and forward drive clutches 14, 15, comprises a spool-shaped valve piston 16 to one end 29 of which pressure fluid passes from an inlet pipe 11 through a leak passage 33 to push the spool against coaxial compression springs 17, 18 controlled by the service brake pedal 20 of the truck, depression of the pedal to apply the brakes reducing the bias of the springs 17, 18 so that the fluid pressure at 29 can move the spool 16 rightwards to close a passage 12 through which fluid is supplied to the clutch engaging mechanism. Simultaneously, a pressure relief pipe 22 leading to a sump is opened, some of the fluid passing through the pipe 22 being diverted to lubricate the selecting mechanism of the reverse and forward clutches 14, 15. A manually operated forward-reverse selector valve 13 directs fluid under pressure from the pipe 12 to either a pipe 48 or a pipe 49 leading to the reverse and forward clutches 14, 15 respectively. A by-pass passage 54 bleeds off fluid from the space 29 at the back of the valve spool 16 to the pipe 12, so that the operating mechanism of the clutches is always full of fluid and the valve spool 16 can move rapidly leftwards to engage the selected clutch when the brake pedal 20 is released.</p> |
