Patent GB-585661-A (GB)
Title: Improvements in or relating to hydraulically operated driving apparatus for chain conveyors and the like
IPC: B65G23/00
Filed: 1943-03-26
Abstract: 585,661. Conveyers. KING, Ltd., G. W., and KING, D. M. March 26, 1943, No. 4959. [Class 78 (i)] [Also in Group XXIX] Hydraulically-operated driving apparatus for chain conveyers and the like comprises a pair of reciprocatable members operable alternately to engage and drive the conveyer chain, each member being operative to drive the.chain in one direction of movement but inoperative when such direction of movement is reversed, a pair of fluid pressure operated motors operatively connected one with each of the reciprocatable members, and a valve adapted to control the supply of high pressure fluid to the motors in such a manner that they are operative alternatively to impart a power stroke to the reciprocatable member associated therewith. To ensure a continuous drive, the return stroke of each member is effected more quickly than the power stroke so that each regains its rear position slightly before the other completes its power stroke. The overhead workshop conveyer system shown includes an endless chain 10 comprising inter-connected flat links 11, as described in Specifications 417,134 and 438,975, [both in Group XXV], the chain being supported at intervals by trolleys 12, Fig. 3, having wheels 13 running in an I-section joist 14. Each reciprocating member comprises a slide 20 or 21, on which is pivotally mounted at 22 a driving arm 15 having an inwardly directed projection 16 adapted to engage in the spaces between the chain links, the rear edge 18 of the projection being curved to facilitate free rearward movement of the arm. A spring 29 tensioned between an anchorage 30 on the slide and a bracket 31 fixed to the arm normally urges the arm about its pivot 22 to engage the projection 16 with the chain. Each channelsection slide 20 or 21 has upper and lower pairs of rollers 23, 24 running in guide rails 25 secured between front and rear transverse frame members 26, 27 of inverted U-shape. Driving Mechanism. The fluid pressure operated motors '35, 36 are supported on the frame member 27 and each consists of a cylinder 38 having a piston 39 connected by a rod 39<1> to the corresponding slide, high pressure fluid supplied from a storage tank 40, Fig. 5, and pump 41, being admitted alternately to the motors to actuate the slides in succession. The pump is connected by a conduit 42 to a two-way valve 43 from which fluid may be delivered through pipes 44, 45 to the high pressure ends of the motors, discharge of fluid from which to the tank 40 is controlled by a valve, assembled with the valve 43, the fluid discharging through the pipes 44, 45, the control valve, pipes 47, 48 and a conduit 49. The system also contains an accumulator 50 supported on the frame member 27 and comprising high and low pressure chambers 52, 53 containing respectively a piston 55 and heavy spring 56 and a piston 57 and light spring 58. Spring 56 maintains the pressure of the fluid passing from the pump to the motors 35, 36, while spring 58 maintains a limited fluid pressure on the back of the pistons 39, the chamber 53 being connected through conduits 59, 60 with the low pressure ends of the motors and through a conduit 61 with the return conduit 49. The limited back,pressure is sufficient during the return movement of each piston to cause it to reach its rearmost position before the power stroke of the other piston is completed. Valve Mechanism. The valve 43 is automatically controlled in accordance with the positions of the slides to supply fluid to the high pressure end of each motor 35 or 36 alternately by means of an arm 46 coupled to an axially movable control rod 65, Figs. 2, 4 by a link 69 and a bracket 67 secured to the rod and extending through a slot 68 in the wall of the rear frame member 26. Two oppositely extending springs 72, 73 attached at their ends 70, 71 to the rod 65, are attached at their other ends 74, 75 to a link 76 connected at its ends to arms 77, 78 rotatably mounted in the frame member 26, movement of the rod 65 being limited by stops 79 which the valve arm 43 engages in its extreme positions while movement of the link 76 is limited by the ends 80, 81 of a pair of slots 82 formed in the frame member 26 and adapted to be engaged by arms 83, 84 rigid respectively with the arms 77, 78. Springs 85 each tensioned between an oppositely extending portion of the arm 83 or 84 and an anchorage 86, retain the arms and therefore the link 76 in either of their or its extreme positions. The arms 83, 84 are adapted to be actuated by extensions 88 on the slides and, being interconnected by the link 76, each arm is automatically pre-set on actuation of the other arm by the corresponding extension 88. Axial movement of the control rod 65 and hence actuation of the valve 43 to control the supply of high pressure fluid to the motors 35, 36 is prevented, until the returning slide reaches its rearmost position, by a pair of levers 90 pivotally mounted at 91 on opposite sides of the frame member 26 and each biassed by gravity to a vertical operative position in which its upper end is positioned in the path of the rod 65. Each lever is adapted to be rocked about its pivot, to permit movement of the rod 65, by the engagement therewith of an adjustable screw 93 in a pin 92 extending rearwardly from each slide. A collar 94 on each pin is maintained by a spring 95 in engagement with the bifurcated end of a rockable lever 98 connected at its other end by a link 99 to the bracket 31, this arrangement enabling the driving arm 15 of the rearard slide to be rocked about its pivot in order to withdraw its projection 16 from the chain until the slide commences its forward movement. Operation. Assuming the slide 21 to have reached a position in which the screw 93 has rocked the corresponding lever 90 out of the path of the valve control rod 65, the rod is moved axially to the position shown in Fig. 2, in which the supply of high pressure fluid to the motor 35 is cut off and directed instead to the motor 36, the lever 90 associated with the slide 20 taking up a vertical position opposite the other end of the rod. The slide 21 is thus moved forwardly, its arm 15 being immediately rocked about its pivot to engage the projection 16 with the chain. At the same time the high pressure end of the motor 35 is opened to exhaust'fluid therefrom back to the tank, this being effected by the transfer of fluid from the low pressure end of the motor 36, during its feed stroke, to the low pressure end of the motor 35 through the conduits 60, 59, the slide 20 being returned to its rearmost position by this transfer of low pressure fluid boosted by the pressure built up in the low pressure accumulator during the feed stroke of the slide.