Actuator for a mine roof support unit
AssigneeGewerkschaft Eisenhutte Westfalla
InventorsWalter Weirich, Werner Grommas
Life of this patent
Estimating the term…
Abstract
A hydraulic control system for a mine roof support unit has a control valve assembly for controlling the hydraulic appliances of the unit, and an actuator for actuating the control valve assembly. The actuator has a valve block provided with a plurality of pairs of spool valves. The spool valves of each pair are detachably fixed in a pair of generally parallel bores formed in the valve block. Each pair of spool valves is provided with a respective rocker arm for actuating purposes. Each of the rocker arms is mounted on a respective cover plate, which covers the mouths of the corresponding pair of bores, and which is detachably secured to the valve block.
Claims11
An actuator for use in the hydraulic control of a mine roof support unit, the actuator comprising a housing, a plurality of pairs of valves, and a respective common rocker arm for actuating the valves of each pair of valves, the valves of each pair of valves being detachably mounted in a respective pair of generally parallel bores formed in the housing, each of the rocker arms being mounted on a respective cover plate which covers the mouths of the corresponding bores, and each of the cover plates being detachably mounted on the housing, wherein a sleeve is detachably mounted on the housing, the sleeve being made of resilient material and extending away from the housing to provide a protective surrounding for the rocker arms, and wherein a resilient protective bellows is arranged on, and extends across, the sleeve, the rocker arms passing through respective apertures in the bellows which thereby conprises means for biasing each of the rocker arms into a position in which neither of the associated valves is actuated.
Dependencies are inferred from the claim text.