Patent GB-292384-A (GB)
Title: Improvements in power shovels
IPC: E02F3/352
Filed: 1927-08-27
Abstract: 292,384. Marks, E. C. R., (Goodman Manufacturing Co.). Aug. 27, 1927. Scoop-arm machines.-An hydraulically-operated power shovel is manually controlled through the medium of two valves, one normally closed for applying the required pressure and the other open normally and serving as a bye-pass. As shown, the device comprises a fluid-pressed holding- jack 4, Figs. 1 and 2, a turntable 5, a beam 17 carrying a scoop 18, an elevating arm 19 on which the beam slides, a motor 6, pump 7, reduction gear 8, and reversible driving mechanism 10. The arm 19 is mounted on a shaft 21 and is elevated thereon by means of a cylinder 22 connected to the hydraulic system, which is shown in Fig. 8, by a swivel connection in axial alignment with trunnions 23 on which the cylinder is mounted. Longitudinal movement of the scoop is obtained by means of two pairs of cylinders 27, 29 acting in opposite directions on the beam 17. The scoop 18 is provided with an ejector plate 31 moved hydraulically by means of cylinders 32. The pump 7 operates through the medium of platform valves 36, front and rear beam valves 37, 38, and jack valves 39. The valves 36 are composed of a series of poppet valves 42-48, Figs. 5 and 6, which are all alike excepting valve 47 and comprise a stem 49, a piston 50, conical head 51, and a bye-pass 52 for equalizing the pressure. The head 51 is lightly pressed to the closed position by a spring 53. The valves 42-48 are arranged in opposing sets, each set closing toward the other set with the exception of valve 47. A hand-lever 58 simultaneously operates the valves 42, 43 in an opposite direction to and together with the valves 45, 46. A second lever 59 similarly and oppositely operates the valves 44, 48. Each lever has its half way neutral position. The lever 58 is provided with means for closing the valve 47 with a movement in either direction and-the lever 59 in the direction of opening the valve 48. Continued opening movements of the lever 58 closes the valve 47. The valves 42-46 and 48 are normally closed and the valve 47 normally open. The latter valve bye-passes the pressure from the pipe 65 through the pipe 66 to a tank. a return pipe 69 leading therefrom to the pump. The valves 43, 45 and 48 close with the pressure of the pump and selectively apply pressure, the valves 42, 44 and 46 selectively releasing the pressure. For supplying fluid pressure to the pairs of cylinders 27, 29, their respective supply pipes 77, 73 are connected by swivel joints 76, 72 with pipes 75, 71 respectively. The pipe 75 communicates with the pressure valve 43 below the head and with release valve 46 above its head. The pipe correspondingly communicates with its respective valves 42, 45. The lifting cylinder 22 is connected by swivel connection 26 and pipe 78 with the valves 44, 48. The beam valves 37, 38 are manually controlled, and connect by pipes 90, 91 and 93, 94 to the hollow plungers of their respective cylinders 27, 29 for reciprocation of the beam or for locking the beam and actuating the ejector plate 31, the latter being operated by means of the lever 58 which is moved to introduce and release alternatively the pressure in opposite ends of the ejector cylinders. Fluid pressure is introduced by means of the jack valves 39 to the jack cylinder 3 from the pipes 64, 120. In Fig. 8, the fluid is idly circulating from the pressure line 64 through the valve 47 into the low pressure line 67, the jack valves 39 being in position for the introduction of pressure to the jack cylinder 3. By actuating the lever 59, the pressure valve 48 is opened for exerting pressure in the cylinder 22 and then the bye-pass valve 47 is closed. By reversing the lever the release valve 44 is opened to release fluid from the cylinder and the valve 47 is opened and the valve 48 closed. By suitably positioning the beam valves 37, 38 the cylinders 27, 28 are connected up in pairs, and when the lever 58 is actuated to open the valves 42 and 43 and then close the valve 47 pressure is applied to and released from the corresponding beam cylinders. A similar actuation of the valves 45, 46 and 47 reverses the action on the beam. The lever 58 controls the movement of the beam 17 or the ejector plate depending on the position of the valves 37, 38. The lever 59 controls the vertical position of the elevating arm 17 and the beam.