HEAD ASSEMBLY

摘要

A head assembly (10) comprises a spear head assembly (12) and a latching system (100) which are coupled together. The spearhead assembly (12) comprises a spear point (16) having a proximal end (18) pivotally coupled about a pivot axis (20) and a sleeve (22) that is biased in a direction toward a pointed end (24) of the spear point (16). The sleeve (22) is coupled with the spear point (16) so that the spear point (16) and the pivot axis (20) can move axially relative to the sleeve (22). The latching system (100) comprises a latch body (102) and two latch dogs (104a) and (104b) which are coupled to the latch body (102) and movable between latching position where the latch dog (16) from the latch body (102) and can engage a latching mechanism and a release position where the latch dogs (104) retract inwardly. The latching system (100) is configured to enable the latch dogs (104) to move parallel to each other rather than pivot when moving between the latch and release positions. The spear head assembly (12) enables the head assembly (10) to be coupled to an overshot to enable tripping through a drill string. The latching system (100) enables the head assembly (10) to selectively engage the latching mechanism inside the drill string to hold the head assembly (10) in at least one axial direction relative to the drill string.