Patent ID: 8267202
Filing Date: 2012-09-18
Classification: E21B,Y10T

Abstract:
1. A rock drill assembly, comprising: a feed channel having a guide rail; a rock drill configured to translate along the guide rail; a tensioner member movably coupled to the feed channel; a chain feed drive fixedly coupled to the feed channel and having a drive sprocket; a chain attached to the rock drill and engaging the tensioner member and the drive sprocket; an actuator associated with the tensioner member and configured to apply a substantially constant tensioning force to the tensioner member to tension the chain, the actuator comprising a through-bore hydraulic cylinder with a plunger and a hydraulic fluid inlet port; and a rod coupled to the tensioner member and extending through the through-bore hydraulic cylinder; so that when pressurized hydraulic fluid is provided to the through-bore hydraulic cylinder, the force on the plunger is transmitted to the rod thereby tensioning the chain.