GB1004913A - Hydraulic winch control mechanism - Google Patents

Abstract

1,004,913. Winches. BALDWIN-LIMA HAMILTON CORPORATION. May 7, 1964 [June 18, 1963], No. 19134/64. Heading B8B. [Also in Division F2] A control mechanism for a winch 23 on a rotatably telescopic crane boom 18 of a mobile crane 10 comprises a reversible winch operating hydraulic motor 26 mounted on the boom 18 a valve 34a on an operation platform 15 of the crane 10 for controlling the fluid flow to and from the motor 26, a brake mechanism 65 (see Division F2) mounted on the boom and coupled to the winch and a shuttle valve 80 interconnecting the hydraulic supply and return lines 61, 62 of the motor 26 and the brake mechanism for rendering the said mechanism inoperative when the motor 26 is operated. The winch 23 comprises a drum 51 freely mounted on a shaft 52 and drivingly connected therewith by an hydraulically operated clutch 130. The shaft 52 is driven through a reduction gear 53 and a shaft 56 from the motor 26. The brake 65 includes a brake drum 66 secured on the shaft 56 and partially surrounded by an adjustable arcuate brake shoe 67, the two ends of which are normally pressed together by a coil spring to normally brake the winch drive. The said spring is disposed in a housing 68 which also incorporates an hydraulic piston and cylinder, Fig. 3 (not shown), whereby the spring can be compressed to release the brake. The clutch 130 comprises a clutch plate 131 keyed to the winch drum shaft 52, a pair of clamptype shoes 132 mounted on a frame 133 integral with the winch drum 51 and which normally engage the plate 131 under spring pressure. These shoes may be disengaged from the plate by actuations of hydraulic piston or cylinder arrangements 134. The latter are energized by a foot pedal operated cylinder 141 on the operation platform 15 which pressurizes the fluid lines 144, 145, 148, 149 coupled by an hydraulic rotary distributer 40 and swivel couplings 146, 147. In operating the winch drum 51 to lift up a load hook 22 via the cable 21, the valve 34a is selected to cause pressurization of lines 37, 61 and passage 44 in the distributer 40 to operate the motor 26. For lowering, the load lines 36, 62 and passage 43 are pressurized, the fluid returning from the motor 26 to the fluid reservoir 31 via the lines 61, 37 and 38. The shuttle valve 80 is placed in the hydraulic circuit and allows the brake feed line 78 to become pressurized coincidental with pressurization of lines 61 or 62, the line 78 exhausting through line 101 which joins a bleed line 102 from the motor 26. A counterbalancing valve 110 (see Division F2) is placed in the line 61 which allows fluid to flow freely through line 61 into the motor 26 to cause raising of the load but restricts the flow through the line 61 in the reverse direction when the load is being lowered. The degree of flow restriction is governed by a cylindrical valve head having peripheral apertures along its length the longitudinal displacement past a valve seat 1 being controlled by a piston and cylinder arrangement pressurized by line 62b from line 62.