Patent ID: 6213223
Filing Date: 2001-04-10
Classification: E21B

Abstract:
A rock drilling apparatus to be located between a rock surface and a support surface for drilling the rock surface, the rock drilling apparatus comprising:a rock drill,a feed for feeding the rock drill in a forward direction towards the rock surface during drilling, the feed being urged in a rearward direction opposite the forward direction during drilling,a rear support cylinder attached to the feed,at least one rear support urged by the rear support cylinder substantially parallel to the rearward direction to engage the support surface,a rear support cylinder desired value means for setting a desired value for pressure in the rear support cylinder,a rear support cylinder pressure detector for detecting the pressure in the rear support cylinder,a front support cylinder attached to the feed,at least one front support urged by the front support cylinder substantially parallel to the forward direction to engage the rock surface,a front support cylinder desired value means for setting a desired value for pressure in the front support cylinder, anda front support cylinder pressure detector for detecting the pressure in the front support cylinder, anda pressure controller responsive to the rear support cylinder pressure detector for controlling supply of pressure fluid to the rear support cylinder to maintain the pressure of fluid in the rear support cylinder substantially at the desired value set by the rear support cylinder desired value means,and wherein the pressure controller is responsive to the front support cylinder pressure detector for controlling supply of pressure fluid to the front support cylinder to maintain the pressure of fluid in the front support cylinder substantially at the desired value set by the front support cylinder desired value means.