Abstract: A generally rectangular transition plate for connecting inclined and horizontal chords of a mine roof truss has one face defining a generally flat planar plate bearing surface adapted to be closely received against a mine roof. The sides and one end of the plate are bent outwardly from the one face. A first opening in the plate adjacent the one end is adapted to receive a mine roof bolt. A second opening in the plate is located adjacent the other end of the plate. A saddle portion extends between the other end of the plate and the second opening and is adapted to receive a truss tie member. The plate has a low profile and sufficient rigidity to sustain the forces present in the truss.

Abstract: An intrinsically safe system controls all miner hydraulic and electrical functions from a hand held miner remote control pendant. Pendant control devices provide on/off control signals to interfaces with miner drive and pump controllers, as well as a group of .+-.6 VDC differential proportional and on/off control signals to respective electronic valve drivers. Valve driver outputs are fed to respective force motors on pilot stage valves which control each hydraulic function. Each valve driver output is modified by offset and dither signals to overcome power stage valve dead band and frictional characteristics. Pilot stage valves have an internal feedback sleeve coacting with a pilot valve spool in a hydraulic servo circuit. Pilot stage valves operate in a pilot oil system which may be isolated from power oil systems.