Patent ID: 8157478
Filing Date: 2012-04-17
Classification: E21B,F16L

Abstract:
1. A rod string pushing and pulling machine for use with a rod string comprising a series of rods coupled to one another end to end, wherein each rod comprises an upset, the rod string pushing and pulling machine comprising: a housing including a front shore plate having an access opening therein through which the rod string extends from the housing; a carriage supported by the housing; a holding mechanism mounted on the carriage, wherein the holding mechanism comprises a pair of opposing pawls configured to engage the upset so that a pushing or pulling movement of the carriage in opposite directions causes pushing or pulling movement of the rod string; a hydraulic thrust cylinder supported by the housing for pushing and pulling the carriage and the rod string, when the pawls are engaged with the upset, upon extension or retraction of the thrust cylinder; and a bungee vise mounted on the housing, the bungee vise having a pair of jaws and an actuator that causes the jaws to engage the upset of a rod supported within the bungee vise to hold the rod string against longitudinal movement when the upset of the rod supported within the holding mechanism is not engaged, and disengage when the upset of the rod supported within the holding mechanism is engaged by the holding mechanism during push and pull movement of the rod string.