Abstract: A quick changeover hydraulic circuit for use in an auger drive mode or percussion hammer mode, controllable in each mode by the same flow regulator. The circuit comprises a first branch circuit which powers a first auxiliary hydraulic powered device and a hydraulic motor for drill steel rotation. A second branch circuit powers a hydraulic percussion motor for a drill steel hammer or a rotary hydraulic motor for an auger, only one of which is in the circuit at one time. An interbranch circuit comprises a priority flow divider which distributes flow. In a first mode with the percussion motor for the drill steel hammer connected into the second branch the flow is delivered to the steel rotation motor and the first auxiliary device. In a second mode with the auger motor connected into the second branch, combined flow from both branches is delivered to the auger motor.

Abstract: A temporary roof support comprising a boom pivotally mounted and positioned on the front of the mining vehicle. A temporary roof support jack is pivotally mounted to the front of said boom. The jack comprises a base structure secured to the boom and extending laterally thereof. The base structure has four pivot pins including an inside pair of pivot pins symmetrically spaced on each side of the base structure and an outside pair of pivot pins symmetrically spaced on each side of the base structure. Two pairs of swing arms are pivoted to said inside pivot pins. Two linkage extensions are pivotally joined to each other and at opposite ends to the free ends of the swing arms. Two extensible hydraulic means are pivotally secured at one end to the outside pivot pins and pivoted at the opposite ends to the swing arms such that the axes of the swing arms and extensible hydraulic means are always crossed. A beam is attached to the pivot joint of the linkage arms for supporting the roof.

Abstract: A filter comprising a filter head, a canister secured to the filter head and a tubular filter within the canister. The filter head has inlet and outlet ports for connecting into a hydraulic conduit. A first passage normally delivers fluid from the inlet port to the outer cylindrical surface of the tubular filter element. A second passage delivers fluid from the interior of the filter element to the outlet port. The filter head has a sliding element between the inlet and outlet ports. The sliding element is spring biased which bias can be overcome by differential pressure across the filter element. An indicator is associated with said sliding element and extends through the filter head to the exterior thereof. The filter head has a butterfly valve in the second passage. A plunger slidably positioned in said filter head is spring biased to a first position in which it extends into the canister in the space normally occupied by the tubular filter element.

Abstract: An unhooking dirty filter alarm for a filter comprising a filter head, canister and tubular filter element. The filter head has a bypass valve therein. Linkages to the outside of the filter element rotate a pointer indicating whether or not the filter element has been bypassed. The linkages are arranged not to restore the pointer after the bypassing condition has abated to thereby latch the information that the filter was bypassed.

Abstract: A drill steel guide or clamp for use with mine roof drilling and bolting machines which guides and clamps the drill steel relative to a standard but which can be kicked out of the way by the advancing drill pod after which time the guide is no longer required for the particular bolt hole being drilled. The clamped guide comprises a clevis body pivotally secured to the standard having two retaining arms individually pivotally mounted to the clevis for rotation into clamping and guiding relation with the drill steel. A unique palm lock comprises extensions for embracing the retaining arms to prevent rotation of the arms out of guiding relationship with the drill steel. The palm lock is arranged to be unlatched when struck by the drill pod or kick plate attached thereto as the drill pod pushes the guide out of the way as it advances.

Abstract: A roof drilling and bolting device comprising a mobile chassis and two cabs mounted to the front of the chassis for independent transverse (outward to the side) movement. The cabs have floors and protective canopies. Extensible hydraulic devices position the cabs outwardly of the chassis. Other extensible hydraulic devices raise and lower the cabs relative to the chassis. Mounted to the front of each cab is a drilling assembly including a rectilinear positioning device for drill pods which provides up-down and side-to-side movement of the drill pod in front of the cab. An extensible standard is positioned by a boom which extends forward of the chassis to provide a temporary roof support.

Abstract: An operator cab and drilling assembly for a roof drilling and bolting device. The cab comprises a floor and a canopy having extensible hydraulic means for adjusting the distance between the cab floor and at least the front edge of the canopy. A horizontal rail extends along the entire length of the front edge of the floor and is spaced therefrom. A roof bolting and drilling apparatus slidably engages the horizontal rail. The rail is mounted by swinging arms to always be parallel to the cab floor.

Abstract: A temporary roof support for mounting to a mining vehicle comprising a boom pivotally mounted to the vehicle and positioned in front thereof for rotation in a vertical plane and an extensible standard pivotally mounted to the front of said boom. An extensible hydraulic device secured at one end to the standard and at the other end to the boom adjusts the angular relationship therebetween. A transverse beam is mounted to the top of the standard for restricted angular movement.

Abstract: A system for mounting two operator cabs to a vehicle chassis for transverse extension. At least one large tube is mounted to the vehicle with its axis pointed in the direction of the operator cab movement. Two smaller tubes of different diameters telescopically engage the large tube and each other and project at opposite ends of the large tube. A bushing is fixed in the opening of the large tube from which the smallest tube extends. Two cab brackets slidably engage the outer surface of the large tube. An outer edge of each cab bracket is fixed relative to one of the smaller tubes which is a cantilever support therefor when the cab is extended outwardly of the length of the large tube. The cabs are slidably mounted to the cab brackets for vertical movement relative thereto.

Abstract: A hydraulic impact tool wherein hydraulic power is used to lift a ram against a bias to store energy and wherein the ram then is permitted to accelerate toward an impliment to which it imparts energy upon impact. A reciprocating cylindrical sleeve slidable about the ram is arranged to control the hydraulic fluid. The sleeve is initially carried in each direction by the ram and is shifted relative to the ram by hydraulic power.