GB1394440A - Handball for mounting on a control lever and including a fluid flow control vlave - Google Patents

Abstract

1394440 Earth working machines KOEHRING CO 3 Nov 1972 [4 Nov 1971] 50855/72 Heading E1F [Also in Divisions F2 and G3] A handle 10 removably mounted at 12 to a control lever 14; e.g. of an earthmover, contains duplicate valve assemblies in parallel bores 16, 18. the valve assemblies being operable by camming levers 20, 120 pivoted to the handle at 22, 122. In the idle position shown, fluid from supply conduit 60 leaking past balls 56, 156 into signal chambers 46, 146 can escape to exhaust 66 since closure members 40, 140 are clear of their respective seats 44, 144. Operation of either lever depresses plunger 24 or 124 causing spring 30, or 130 to bias the closure member 40 or 140 onto its seat and simultaneously unseat ball 56 or 156, the effect being to establish in the signal chamber 46 or 146, and the associated signal port, a control pressure related to the force applied to the lever 20 or 120. As shown in Fig 7, air is supplied to the handle from pressure regulator 200 and one signal port is connected to a relay valve controlling one servomotor 206 of a directional control valve 208, the opposing servomotor being controlled in like manner by the pressure in the other signal port. Ram 210 then moves at a speed controlled by operation of levers 20, 120 the handle may be detached from the lever 14 to allow the operator to control operation of the earthmover from an alternative point, e.g. when the earthmover is digging a trench and the operator is unable to see the bottom of the trench from the cab.