Abstract: A battery management system maintains a charge on at least one. auxiliary battery by switching the auxiliary battery automatically into parallel with the main battery charging circuit or with the auxiliary load. The system uses the AC component of the charging signal of a vehicle or boat charging system to trigger switching circuits coupled to operate relays or similar switching means which couple the auxiliary battery to the main charging circuit. When no charging signal is present, i.e., when the vehicle or boat engine is turned off, the auxiliary battery is switched automatically out of the charging system and is charged and in condition for use. A delay circuit can be provided for providing non-shorting operation, especially for use with more than one auxiliary battery which batteries are charged in parallel and loaded in series, whereby the combined series voltage of the auxiliary batteries would exceed the vehicle or boat supply voltage.

Abstract: A battery management system maintains a charge on at least one auxiliary battery by switching the auxiliary battery automatically into parallel with the main battery charging circuit or with the auxiliary load. The system uses the AC component of the charging signal of a vehicle or boat charging system to trigger switching circuits coupled to operate relays or similar switching means which couple the auxiliary battery to the main charging circuit. When no charging signal is present, i.e., when the vehicle or boat engine is turned off, the auxiliary battery is switched automatically out of the charging system and is charged and in condition for use. A delay circuit can be provided for providing non-shorting operation, especially for use with more than one auxiliary battery which batteries are charged in parallel and loaded in series, whereby the combined series voltage of the auxiliary batteries would exceed the vehicle or boat supply voltage.

Abstract: A mining vehicle has a body with a center boom extending forwardly from the body. A temporary roof support is mounted on the outer end of the center boom. The roof support has a base, a telescopic column, and a cross beam on top of the column with auxiliary beams pivotally connected to the cross beam to engage the roof. Hydraulic jacks are connected between the base and the outer ends of the beams, respectively. A pedestal is pivotally mounted on the front end of the body, on each side of the center boom, to support a drill boom. A drill head is pivotally mounted at the outer end of the drill boom and is vertically movable by the drill boom for roof drilling. Each drill boom has the end opposite the drill head received in a track on the pedestal which serves to maintain the drill head on a vertical axis in any position of the drill boom. Each pedestal, at its inner end, has a laterally extending arm, the outer end of which is pivotally connected to the body at a pivot joint.

Abstract: A completely flexible dipole antenna is formed from coaxial cable having a braided wire core with skirt also formed of shielding over a flexible sleeve. A coil spring which is not electrically active supports the antenna above the connector. A non-wearing female connector utilizes a flexible conductive elastomer contact contained within an insulating body.

Abstract: A drill housing is pivotally connected to the forward end portion of a boom member that swings upwardly from a frame of a mobile drilling machine. A hydraulic motor is secured to the gear housing and provides rotary power from a drive shaft through a pair of meshing gears to a drill chuck that is arranged to receive a drill bit or a roof bolt. A percussion weight is concentrically positioned within the drill housing and is axially aligned with the drill bit for imparting percussive forces to the drill bit. The percussion control is maintained through a servovalve that is supported on the drill housing and is controlled remotely by an electronic control module. The servovalve controls the flow of pressurized fluid from a source through ports in the drill housing connected to the servovalve by conduits to actuate a piston member for oscillation within the drill housing. Oscillation of the piston imparts a percussive force upon the percussion weight which is transmitted to the drill bit.