end region 184 the later containing the ball receptacles 178 a detent ball lock release collar 186 includes respective interior surface regions 188 and 190 sized for respectively sliding along the exterior surface regions 182 and 184 with it being noted that due to the fact that the surface region 188 is at a lesser diameter than the surface region 190 an annular rightwardly facing surface 192 is defined at the juncture of the two regions a port 194 is provided in the collar 186 in communication with the surface 192 leakage of fluid along the respective interfaces between the left and right end regions 182 and 184 of the ball carrier 176 and the left and right end regions 188 and 190 of the lock release collar 186 is prevented by appropriate seals not numbered received in annular grooves provided in the left and right regions of the ball carrier 176 an annular ball release groove 196 is provided in the interior surface region 190 of the collar 186 at a location adjacent its right end when a source of pressurized fluid is coupled to the port 194 the collar 186 is shifted to a leftward ball release position as shown in fig4 wherein the ball release groove 196 is positioned in register with the.