| 摘要 |
<p>1488576 Controlling tracked vehicles CATERPILLAR TRACTOR CO 29 Jan 1975 [1 Feb 1974] 3861/75 Heading B7H A tracked vehicle having left and right tracks each controlled by an associated hydraulicallyactuated brake and an associated spring-engaged hydraulically-disengaged clutch, is provided with a control system 10 for selectively actuating the brakes and disengaging the clutches to enable steering and braking of the vehicle, the control system 10 comprising manually-operable levers 44, 44 movable to actuate valves 18, 18 controlling flow of hydraulic fluid from supply lines 31, 31 to cavities 22, 22 of left and right brake boosters 11, 12, and to a control valve 13 controlling the flow of hydraulic fluid to the left and right clutches (not shown). As illustrated, each lever 44 is operable through an associated plunger 17 to cause axial movement of a valve spool 24 of the associated valve 18. Each brake booster 11 or 12 includes a piston 19 arranged to cause operation of the associated brake through a linkage including a crank 14. The control valve 13 includes a valve spool 63 which is moved by unbalanced pressures in lines 53, 54 to an off-centre position to establish communication through an appropriate port 68 or 69 with the appropriate clutch. In the position of the control system 10 as shown in Fig. 1, the lever 44 associated with the left brake booster 11 has been moved so as to cause disengagement of the left clutch. Continued movement of the lever 44 associated with the left brake booster 11 causes operation of the left brake. Both left and right brakes may be operated simultaneously without disengagement of the clutches, by moving the levers 44 to the positions depicted in Fig. 2 (not shown). The manually-operated levers 44 may be replaced, in a modification of the illustrated control system 10, by foot-operated pedals.</p> |
