Reversible pump 1 delivers fluid from the tank to hydraulic motor 2 which rotates lead screw 8, linked to the rotor of motor 2. This feeds the drill head along the base ways. As the head travels, its trip dogs a turn reversing lever 3 together with a pinion attached to the lever. The pinion meshes with the gear rack of cylinder 4. As cylinder 4 moves to the right, the increased pressure in its left end moves piston 5 to the right. Gear rack e on the rod of piston 5 turns pinion 6 which is linked to the regulating lever of pump 1. In turning, the lever reverses pump 1 and the rotor of motor 2 begins to rotate in the reverse direction. This reverses the travel of the drill head. Cam 7 varies the rate of feed of the drill head. Detent 9 indexes the positions of lever 3.
$4199$CHP,Dr$