GB970720A - Power controlled winch - Google Patents

Abstract

970,720. Reverse gear; friction clutches. HYSTER CO. June 20, 1961 [June 23, 1960], No. 22298/61. Headings and F2D. [Also in Division B8] A winch drum 7, Fig. 1, is driven in the forward or reverse directions through alternative gear trains 25 or 31 coupled to a pair of fluid pressure operated friction clutches 17, 19, selectively controlled by a single manually-operated valve 41 having four operative positions for braking, free running or driving in either direction. In the first or neutral position, as shown in Fig. 1, the main supply pressure in line 72 from the pump 43 is cut off so that the clutches 17, 19 are disengaged and the drum is braked through the return spring 11 of a brake cylinder 47. In the second position (Fig. 2, not shown), the fluid pressure is supplied to release the brake 9 for free spooling of the drum 7 while the clutches 17, 19 remain disengaged. In the third and fourth positions (Fig. 3, 4, not shown), the clutch 17 or 19 is engaged and the brake released for forward or reverse drive. A separate inching control valve 51 is provided in the pump return circuit for applying a reduced pressure in the brake line 85 for partially releasing the brake 9, a spring 101 and pilot line 103 providing a degree of feel for the operator. Each clutch 17, 19 has provision for cooling and lubricating the friction discs by leakage of oil from the operating pistons 61, through a normally open spring-loaded valve 65 and restriction passages 67. Low pressure oil is normally supplied to the clutches through valve 51 or a reducing valve 81 for maintaining a cooling flow without operation of the clutches. On application of the full clutch operating pressure, the valves 65 automatically close to prevent excessive loss of oil.