Abstract: A tool which connects the last sucker rod of a sucker rod string to a downhole pump has a circularly cylindrical cylinder and piston so that the piston slides reciprocally and rotates freely within the cylinder. However, the closed upper end of the cylinder and the upper face of the piston have a cooperable tongue and groove which prevent relative rotational motion of the piston in the cylinder when the tongue is engaged in the groove so that the tool can be disconnected from the pump in response to rotation of the string at the uppermost stroke of the plunger to engage and turn the tongue and groove.

Abstract: A tool which connects the last sucker rod of a sucker rod string to a downhole pump has a circularly cylindrical cylinder and piston so that the piston slides reciprocally and rotates freely within the cylinder. However, the closed upper end of the cylinder and the upper face of the piston have a cooperable tongue and groove which prevent relative rotational motion of the piston in the cylinder when the tongue is engaged in the groove so that the tool can be disconnected from the pump in response to rotation of the string at the uppermost stroke of the plunger to engage and turn the tongue and groove.

Abstract: A tool which connects the last sucker rod of a sucker rod string to a downhole pump has a circularly cylindrical cylinder and piston so that the piston slides reciprocally and rotates freely within the cylinder. However, the closed upper end of the cylinder and the upper face of the piston have a cooperable tongue and groove which prevent relative rotational motion of the piston in the cylinder when the tongue is engaged in the groove so that the tool can be disconnected from the pump in response to rotation of the string at the uppermost stroke of the plunger to engage and turn the tongue and groove.

Abstract: A tool which eliminates the need for "tapping" in downhole reciprocating pump applications is connectable between the last sucker rod of a sucker rod string and the downhole pump. The tool has a cylinder with a closed end and an internal annular seat proximate an open end houses a piston whch reciprocates slidably within the cylinder and is free to rotate within the cylinder. The travel of the piston is limited in one direction by the closed end of the cylinder and in the opposite direction by the seat. The closed end of the cylinder is externally adapted for connection of the tool between the last sucker rod of the sucker rod string and the pump and the piston has a portion extending through the open end of the cylinder which is also adapted for connection of the tool between the last sucker rod of the sucker rod string and the pump.