Abstract: A mine roof support comprises a base formed of two base members, a beam disposed therebetween, jacks for lifting the base members or the beam one relative to the other and a jack for advancing the base member or the beam one relative to the other. A roofing bar structure is supported from the base members by extendible props and an elevated platform is disposed between the base and the roofing bar structure. The support is advanced by lifting, advancing and lowering the beam relative to the base members and then lifting, advancing and lowering the base members relative to the beam.

Abstract: A percussive tool, for use in mining, quarrying, or excavating, comprising a reciprocable mass movable in one direction against the resistance of a spring by a movable permanent magnet assembly. A hydraulic ram moves the permanent magnet assembly. A plate between the ram and the magnet assembly acts as a flux diverter such that as the assembly is moved proximate the plate by the ram, flux passing through the mass is reduced and the spring forces the mass to impact a tool shank.

Abstract: A pressure fluid operated impact type tool having cyclic pressure fluid operation of a reciprocable hammer piston, and for which there is provided accumulator means connected directly to pressure fluid supply and/or return of the tool.

Abstract: A vehicle for use in underground mining operations is disclosed which is adapted for ready conversion between personnel and materials transportation by the provision of a movable flat panel type platform or platform element movable between a first position, corresponding to a personnel transportation mode of operation, and a second position, corresponding to a materials transportation mode of operation. A bar type member extends from a seat structure transverse to its longitudinal direction which coincides with the longitudinal axis of the vehicle. The bar type member provides a horizontal support surface along with the top of the seat structure for supporting the platform in its materials transportation mode of operation. The seat structure comprises a pair of seats arranged in back-to-back relationship along the longitudinal axis of the vehicle and includes a space therebetween for the storage of said platform means in the personnel carriage mode of operation.

Abstract: In a typewriter of the kind having a carriage movable vertically relative to the type bar assembly to provide three cases of type, the carriage rests on a shift member slidable vertically in guides formed in the body of the typewriter and a spring acts between the body and the shift member biassing the shift member to an intermediate position. One shift key moves the shift member to a lowermost position, overcoming the spring bias, and a second shift key moves the shift member to an uppermost position, overcoming the weight of the carriage.

Abstract: Control units at each support have means for receiving function initiating signals from a communication system common to the supports, means responsive to those function initiating signals for issuing corresponding control signals to component elements of the associated support and means for transmitting data to the communication systems. A remote control unit has means for issuing control signals including such function initiating signals over the communication system, means for receiving data from the supports, means for specifying a sequential or automatic mode wherein support advancing means are successively operated sequentially, and means for displaying data from and relating to the supports.

Abstract: A vehicle for use in mine workings for enlarging a tunnel or for forming a heading and comprising a wheeled chassis having a rock breaker and a bucket loader mounted thereon further includes a conveyor means extending generally longitudinally of the chassis to receive rock and spoil collected by the bucket loader at the forward end of the chassis and to discharge such rock and spoil at the rearward end of such chassis. Rams are provided laterally of the chassis for supporting the same relative to opposed surfaces of the workings.

Abstract: A materials transporting machine, of particular application in mining, has a boom assembly mounted on a vehicle or carriage, which boom assembly includes a telescoping boom which is maneuvering both horizontally and vertically and which can be withdrawn to a stowed position within the vehicle by utilizing pressure fluid operated means which serve for effecting telescoping movement of the boom.

Abstract: A boom arrangement for a bucket loader of particular use in the context of low headroom mine workings comprises two articularly connected boom elements having ram means for varying the relative angular positions thereof and a further ram means for raising or lowering the articularly connected elements, that ram means intended for varying the relative angular positions of the articularly connected boom elements being disposed within the acute angle formed by and between such elements.

Abstract: A mounting arrangement for a mineral displacing tool comprises a carrier for the tool and pivot means pivotally securing the carrier to a support. A link member is attached at one end to the pivot means, and first and second pressure-fluid-operated rams are pivotally connected to act between the other end of said link means and the carrier and the support, respectively. Each ram serves to extend the arc of slewing of the carrier with respect to the support attainable by means of the other ram. Preferably, one of the rams is arranged to slew the carrier in a clockwise direction from a given position, and the other of the rams is arranged to slew the carrier in a counter-clockwise direction from the given position.

Abstract: A gland seal arrangement for effecting a fluid seal between two relatively movable parts wherein the loading applied to an annular sealing member in contact with such parts is derived from a coaxially arranged, sleeve-like thrust member sensitive to the pressure of the fluid being sealed so that with increasing fluid pressure the loading applied to the sealing member is correspondingly increased.