Patent ID: 7950449

Claim:
An apparatus for use in coupling a sucker rod string to a downhole pump, comprising: a) a body having first and second ends, a side wall and a cavity between the first and second ends; b) a plunger located in the body cavity, the plunger structured and arranged to reciprocate in the body cavity, the plunger having an upper end portion, the plunger having a shaft that extends out through the body second end, the plunger lacking a valved fluid passage that allows fluid to flow through the plunger; c) first and second fluid ports providing fluid communication from the body cavity to an exterior of the body, the first fluid port located between the plunger and the body first end, the second fluid port located between the plunger and the body second end; d) a coupler attached to the plunger shaft, wherein when the apparatus is put into use the body first end will couple to one of either the sucker rod string or the pump and the coupler will couple to the other of the sucker rod string or the pump; e) the body first end having a first surface located in the cavity and extending longitudinally therein, the plunger upper end portion having a second surface extending longitudinally within the cavity, the first and second surfaces cooperating with one another such that the plunger can reciprocate in the body cavity, with one of the first and second surfaces limiting the rotation of the other of the first and second surfaces about a longitudinal axis of the apparatus for substantially all of the plunger reciprocation stroke.