| 摘要 |
<p>964,069. Clutch control. TOWMOTOR CORPORATION. April 17, 1963 [Nov. 14, 1962], No. 15037/63. Headings F2D and F2L. A clutch operating mechanism for a vehicle such as a lift truck, which can be operated to provide forward or reverse drive is also operable to control the speed of the vehicle by controlling clutch slip to allow creeping or inching movement of the vehicle. A valve 45, Fig. 5, is actuated from the neutral position shown to control the supply of fluid pressure from a conduit 41 to either outlet 21, 22 which lead to the opposite ends of a cylinder housing a piston which actuates the clutch. Feed through outlet 21 actuates the piston for forward drive and feed through outlet 22 provides reverse drive. The supply of fluid to the conduit 41 is controlled by a valve 81, which in the position shown allows the full supply from an inlet 27 to a groove 52 to flow to groove 56 and conduit 58. The flow from conduit 58 to conduit 41 takes place through a restriction 63 and also through a clearance passage 65a until the pressure in the passage 41 moves a valve 70 to close the passage 65a and flow then occurs through the restriction 63 only, this reduces the velocity of the piston towards the end of its stroke to prevent jerking movements of the vehicle i.e. this action reduces the speed of the full engagement of the clutch. To control the clutch slip, the valve 81 is provided with a groove or flat 83 extending along part of the land 82 as far as a shoulder 84. When the valve 81 is moved inwards to a position in which the shoulder 84 clears the bore part 54b the fluid in groove 52 flows to the groove 56 through the flat 83 and most of the fluid in the groove 56 flows to passage 86 connected to exhaust, thus the pressure fed through passage 58 is regulated to control the position of the piston and hence the degree of engagement of the clutch. The valve 81 is connected to a bracket 98, Fig. 3, which is actuated manually by a lever 106. In the position shown, the valve 81 is in the position shown in Fig. 5 i.e. the clutch is in full engagement if the valve 45 has been actuated. When the lever 106 is depressed, the valve 81 moves inwards by rotation of a floating lever 96 to reduce the pressure to the piston cylinder device. Movement of the piston causes rotation of a shaft 15 to actuate the clutch. The shaft 15 carries a bracket 89 which on rotation in either direction, corresponding to forward or reverse drive, moves a lever 91 to the right. The lever 91 is connected to the floating lever 96 and its movement to the right acts to rotate the lever 96 to move the valve 81 outwards thus providing feedback to the valve. The position of lever 106 thus provides a corresponding engagement of the clutch to provide a controlled slip and hence creeping speed of the vehicle. U.S.A. Specification 2,861,480 is referred to.</p> |
