Hydrostatic shear pin

Claim 1

An apparatus for selectively restraining and releasing relative rotational movement of a first component connected to a second component, comprising: (a) a housing mounted in the first component, having an internal recess opening towards the second component; (b) a plug having a first portion slidingly engaged and constrained within the recess of the housing, but not fully occupying the space therein, defining an inner surface of the plug facing the recess, and having a second portion projecting beyond the housing and the first component so as to engage in an aligned hole in the second component when the plug is fully extended with respect to the housing, said second portion defining an outer surface of the plug; (c) conduit means for exposing the outer surface of the plug to ambient fluid pressure so as to tend to retract the plug into the recess; (d) locking means for restraining the retracting of the plug until the force exerted by the ambient fluid pressure equals or exceeds the precalculated level, whereupon the locking means will disengage, allowing the plug to retract into the recess, thereupon permitting relative rotational movement of the first component with respect to the second component; (e) said locking means comprising a plurality of rigid pins mutually engaging radially aligned holes in the retracting plug and housing, said rigid pins so constructed and arranged as to break at the application of the precalculated force acting upon the outer surface of the plug, (f) said locking means further including a quantity of pressurized gas sealed within the remaining space of the recess of the housing, (g) said housing further including a shoulder in the recess, said shoulder being of larger diameter than the recess, so as to allow the pressurized gas within said recess and shoulder to escape when said plug retracts fully into said shoulder.

Claim 2

An apparatus for selectively restraining and releasing relative rotational movement of a first component connected to a second component, comprising: (a) a housing mounted in the first component, having an internal recess opening towards the second component; (b) a plug having a first portion slidingly engaged and constrained within the recess of the housing, but not fully occupying the space therein, defining an inner surface of the plug facing the recess, and having a second portion projecting beyond the housing and the first component so as to engage in an aligned hole in the second component when the plug is fully extended with respect to the housing, said second portion defining an outer surface of the plug; (c) conduit means for exposing the outer surface of the plug to ambient fluid pressure so as to tend to retract the plug into the recess; (d) locking means for restraining the retracting of the plug until the force exerted by the ambient fluid pressure equals or exceeds the precalculated level, whereupon the locking means will disengage, allowing the plug to retract into the recess, thereupon permitting relative rotational movement of the first component with respect to the second component; (e) said locking means comprising a plurality of rigid pins mutually engaging radially aligned holes in the retracting plug and housing, said rigid pins so constructed and arranged as to break at the application of the precalculated force acting upon the outer surface of the plug, (f) said locking means further including a quantity of pressurized gas sealed within the remaining space of the recess of the housing, (g) said housing further including a shoulder in the recess, said shoulder being of larger diameter than the recess, so as to allow the pressurized gas within said recess and shoulder to escape when said plug retracts fully into said shoulder.

Claim 7

An apparatus relative movement of a first object with respect to a second object, comprising: (a) a first object comprising a housing having a recess therein; (b) a second object sealingly and slidably engaged and constrained within said recess, but not fully occupying the space therein, defining an inner and outer surface with respect thereto; (c) exposure means for subjecting the outer surface of the second object to a pressurized fluid, tending to retract the second object into the recess; (d) locking means for restraining the retraction of the second object until the force exerted by the fluid pressure equals or exceeds a precalculated level, whereupon the locking means will disengage, allowing the second object to retract into the recess, (e) said locking means comprising a plurality of rigid pins mutually engaging radially aligned holes in the second object and housing, said rigid pins so constructed and arranged as to break at the application of a precalculated force acting upon the outer surface of the second object, (f) said locking means further including a quantity of pressurized gas sealed within the remaining space of the recess of said housing, (g) said housing further includes a shoulder in the recess, said shoulder being of larger diameter than the recess, so as to allow the pressurized gas within the recess to escape when said plug fully retracts into said shoulder.

Claim 8

An apparatus relative movement of a first object with respect to a second object, comprising: (a) a first object comprising a housing having a recess therein; (b) a second object sealingly and slidably engaged and constrained within said recess, but not fully occupying the space therein, defining an inner and outer surface with respect thereto; (c) exposure means for subjecting the outer surface of the second object to a pressurized fluid, tending to retract the second object into the recess; (d) locking means for restraining the retraction of the second object until the force exerted by the fluid pressure equals or exceeds a precalculated level, whereupon the locking means will disengage, allowing the second object to retract into the recess, (e) said locking means comprising a plurality of rigid pins mutually engaging radially aligned holes in the second object and housing, said rigid pins so constructed and arranged as to break at the application of a precalculated force acting upon the outer surface of the second object, (f) said locking means further including a quantity of pressurized gas sealed within the remaining space of the recess of said housing, (g) said housing further includes a shoulder in the recess, said shoulder being of larger diameter than the recess, so as to allow the pressurized gas within the recess to escape when said plug fully retracts into said shoulder.