CPC E21B 17/03 (2013.01) | 12 Claims |
1. A latch release mechanism having a longitudinal axis and acting between an upper latch assembly and a lower latch assembly, said upper and lower latch assemblies being coaxially aligned with the latch release mechanism, and wherein:
(a) the upper and lower latch assemblies are operable between:
a latched position, in which relative axial separation of the upper and lower latch assemblies is constrained; and
an unlatched position, in which relative axial motion of the upper and lower latch assemblies is permitted within a defined range;
in response to application of relative rotation, and an associated torque, between the upper and lower latch assemblies in a first rotational direction;
(b) the upper latch assembly defines one or more trigger reaction dog pockets; and
(c) the upper latch assembly axially carries a generally cylindrical main body assembly having a main body bore;
wherein the latch release mechanism is coaxially disposed within the main body bore and comprises:
(d) a bumper element coupled to the lower latch assembly, such that when the bumper element is moved axially relative to the lower latch assembly, the bumper element will also rotate relative to the lower latch assembly; and
(e) a trigger element coupled to the bumper element and the lower latch assembly so as to be at least axially movable relative to the bumper element, and so as to be axially and rotationally movable relative to the lower latch assembly within a defined range, wherein the trigger element defines one or more trigger dog teeth configured for axial engagement and disengagement with the one or more trigger reaction dog pockets of the upper latch assembly;
such that when the one or more trigger dog teeth are disposed within the one or more trigger reaction dog pockets:
application of an axial force to the bumper element will tend to cause axial stroking of the bumper element relative to the lower latch assembly so as to urge relative rotation between the upper and lower latch assemblies in the first rotational direction to move the upper and lower latch assemblies from the latched position to the unlatched position, with the associated torque being transmitted through the trigger element; and
application of additional axial force and the resultant axial and rotational displacement of the bumper element relative to the lower latch assembly will cause withdrawal of the one or more trigger dog teeth from the one or more trigger reaction dog pockets.
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