Importance

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Abstract

A jack for installing in a mine a plurality of elongate extensible panels adapted to extend vertically in side-by-side relation from the floor to the roof of a passageway in a mine. Each panel comprises a first elongate member consituting a lower member of the panel and a second elongate member constituting an upper member of the panel, each member having a web and flanges at opposite sides of the web, one of the members having a telescoping sliding fit in the other. The upper member of each panel has a head at its upper end and the lower member of each panel has a foot at its lower end. The jack comprises a base adapted to fit between the flanges of a lower panel member and engage the foot of the lower panel member, an extensible member having a crosshead at its upper end adapted to fit between the flanges of an upper panel member and engage the head of the upper panel member, a guide extending up from the base guiding the extensible member for up and down movement relative to the guide and the base, a hydraulic jack cylinder extending up from the base coaxially with the guide having a lift member movable up and down for raising and lowering the extensible member, a hydraulic pump on the base for pumping hydraulic fluid to the cylinder for moving the lift member and the extensible member upwardly, and a mechanism for operating the pump comprising a handle pivoted on the guide at a level convenient for an operator and a link from the handle to the pump.

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First Claim