Patent ID: 8152492
Filing Date: 2012-04-10
Classification: F04B,Y10T

Abstract:
1. A linear rod pumping apparatus, for imparting reciprocating substantially vertical motion to a rod of a sucker-rod pump having a pump stroke, the apparatus comprising: a linear mechanical actuator arrangement, having a substantially vertically movable member attached to the rod of the sucker-rod pump for imparting and controlling reciprocating vertical motion of the rod of the sucker-rod pump; and a reversible motor having a reversibly rotatable element thereof operatively connected to the substantially vertically movable member of the linear mechanical actuator arrangement in a manner establishing a fixed relationship between the rotational position of the motor and the vertical movement of the vertically movable member as the reversibly rotatable motor is alternately rotated in a first direction for a first portion of the pump stroke and then in a second opposite direction during a second portion of the pump stroke; the linear mechanical actuator arrangement including a rack and pinion gearing arrangement, with the rack being disposed for operation in a substantially vertical direction for reciprocating motion along a pumping axis; the rack being operatively connected in gear mesh relationship with the pinion, and the pinion being operatively connected to a rotating output of the motor, such that rotation of the motor in the first direction is accompanied by a substantially vertically upward motion of the rack along the pumping axis, and such that a substantially vertically downward motion of the rack along the pumping axis is accompanied by rotation of the motor rotatable element in the second direction opposite the first direction; the rack also being operatively connected to the rod of the sucker-rod pump for imparting vertically upward motion to the rod of the sucker-rod pump along the pumping axis when the rack is moving upward; and the rack further being operatively connected to the rod of the sucker-rod pump such that the rod of the sucker-rod pump exerts a substantially vertically downward directed force on the rack, acting substantially along the pumping axis, during a portion of the pump stroke; the rack having a longitudinally directed opening therein extending along the pumping axis from a bottom end of the rack to a top end of the rack, when the linear mechanical actuator is operatively disposed above the sucker-rod pump; the rack also having an upper end thereof adapted for operative attachment of the rod thereto; the upper end of the rack defines a hole therethrough and an upper load bearing surface thereof; the rod has an upper end thereof slideably extending through the hole in the upper end of the rack; and the linear mechanical actuator arrangement further including a rod securing clamp fixedly attached to the upper end of the rod above the upper end of the rack; the rod securing clamp having a lower load bearing surface thereof adapted for bearing contact with the upper load bearing surface of the upper end of the rack, for transferring force between the rod and the upper end of the rack when the lower load bearing surface of the clamp is in contact with the upper load bearing surface on the upper end of the rack; the rack having a substantially U-shaped cross section, with first and second legs extending from a bright section in such a manner that the legs and the bright section define the longitudinally directed opening in the rack, in the form of an open channel disposed about the pumping axis, with an outer surface of section, facing substantially oppositely from the legs including gear teeth of the rack for engagement with corresponding gear teeth of the pinion; the linear rod pumping apparatus also having one or more guide rollers bearing against longitudinally extending distal edges of the legs of the rack, substantially opposite the pinion, for urging the rack into gear mesh relationship with the pinion; the linear rod pumping apparatus further having a pair of guide bars bearing against the legs of the rack, substantially opposite from one another, for urging the rack into axial gear mesh relationship with the pinion.