Hinge with spring pre-load transfer mechanism

1. An apparatus comprising a latching hinge including:

a first member;

a second member rotatably coupled to the first member about a hinge pivot;

a latch link connected with the first member;

a latch hook connected with the second member;

a spring-loaded tensioning device; and

a trigger mechanism, wherein:

the first member and the second member are configured to be transitioned between a hinge-open state and a hinge-closed state by rotating one of the first member and the second member with respect to the other of the first member and the second member about the hinge pivot,

at least a portion of at least one of the latch link and the latch hook is configured to move relative to the first member and the second member, respectively, such that the latch hook and a latch portion of the latch link latch together as the first member and the second member are transitioned into the hinge-closed state,

the latch link and the latch hook prevent the first member and the second member from being transitioned into the hinge-open state from the hinge-closed state when the latch portion of the latch link and the latch hook are latched together,

the spring-loaded tensioning device is configured to be transitioned between a first compressed state and a second compressed state,

a tensile load is induced in the latch link and the latch hook when the spring-loaded tensioning device is in the second compressed state and the latch portion of the latch link and the latch hook are latched together, and

the trigger mechanism:

(i) is configured to be transitioned between a untriggered state and a triggered state,

(ii) maintains, in the untriggered state, the spring-loaded tensioning device in the first compressed state,

(iii) allows, in the triggered state, the spring-loaded tensioning device to transition from the first compressed state to the second compressed state, and

(iv) is configured to transition from the untriggered state to the triggered state after the latch portion of the latch link and the latch hook have latched together.

2. The apparatus of claim 1 , wherein:

the latch hook is rotatable about a first pivot,

the spring-loaded tensioning device is configured to exert a first compressive load on a portion of the latch hook to develop a torque about the first pivot when transitioning from the first compressed state to the second compressed state, and

the latch hook is drawn into contact with the latch portion of the latch link responsive to the developed torque.

3. The apparatus of claim 2 , further comprising a latch link bias spring, wherein:

the latch link bias spring is configured to bias the latch link towards the position the latch link is in with respect to the first member when the latch link and the latch hook are latched together.

4. The apparatus of claim 3 , wherein:

the latch link is configured to rotate about a latch link pivot,

the latch portion of the latch link encounters a sloped surface of the latch hook as the first member and the second member transition from the hinge-open state to the hinge-closed state, and

the sloped surface of the latch hook is oblique to the direction along which the tensile load is induced and engages with the latch portion so as to cause the latch link to rotate about the latch link pivot and deflect the latch link bias spring as the first member and the second member transition into the hinge-closed state.

5. The apparatus of claim 1 , wherein the spring-loaded tensioning device includes a linear spring selected from the group consisting of: a coil spring and a plurality of Belleville washers stacked on a common guide that passes through the center of each Belleville washer.

6. The apparatus of claim 5 , wherein the spring-loaded tensioning device has a spring extension axis aligned with the direction along which the tensile load is induced in the latch link and the latch hook when the spring-loaded tensioning device is in the second compressed state and the latch portion of the latch link and the latch hook are latched together.

7. The apparatus of claim 5 , wherein the spring-loaded tensioning device has a spring extension axis perpendicular to the direction along which the tensile load is induced in the latch link and the latch hook when the spring-loaded tensioning device is in the second compressed state and the latch portion of the latch link and the latch hook are latched together.

8. The apparatus of claim 1 , wherein:

the latch link is movably connected with a latch link rotation arm,

the latch link rotation arm is configured to rotate about a first pivot,

the spring-loaded tensioning device is configured to exert a force on a portion of the latch link rotation arm to generate a torque about the first pivot when transitioning from the first compressed state to the second compressed state, and

the latch portion of the latch link is drawn into contact with the latch hook responsive to the torque.

9. The apparatus of claim 1 , wherein the trigger mechanism includes:

a lever arm component configured to rotate about a fulcrum,

a trigger, and

a release mechanism, wherein:

the spring-loaded tensioning device exerts a first compressive load on a portion of the latch hook in the first compressed state and a second compressive load on a portion of the latch hook in the second compressed state,

the latch hook contacts the lever arm component and transfers the first compressive load from the spring-loaded tensioning device to a first contact zone of the lever arm component and along a first peak magnitude vector when the trigger mechanism is in the untriggered state and transfers the second compressive load to the latch portion of the latch link when the trigger mechanism is in the triggered state,

the release mechanism is configured to contact the lever arm component at at least one second contact zone and apply a third compressive load on the at least one second contact zone and along a second peak magnitude vector when the spring-loaded tensioning device is in the untriggered state, and

the release mechanism is configured to release the lever arm component by removing the third compressive load responsive to engagement with a portion of the first member.

10. The apparatus of claim 9 , wherein:

the release mechanism is provided by at least one spring arm with a detent,

the detent engages with the lever arm component at the second contact zone and resists movement of the lever arm component due to the first compressive load when engaged,

the trigger is configured to contact the at least one spring arm and to deflect the at least one spring arm as the first member and the second member are transitioned into the hinge-closed state, and

the deflection of the at least one spring arm by the trigger causes the detent to move such that the detent releases the lever arm.

11. The apparatus of claim 9 , wherein:

the shortest distance A between the first peak magnitude vector and the fulcrum is at least an order of magnitude less than the shortest distance B between the second peak magnitude vector and the fulcrum.

12. The apparatus of claim 11 , wherein:

the shortest distance A between the first peak magnitude vector and the fulcrum is less than 1/50 th of the shortest distance B between the second peak magnitude vector and the fulcrum.

13. The apparatus of claim 9 , wherein:

the first compressive load is approximately 1500 lbf±200 lbf,

the second compressive load is approximately 750 lbf±100 lbf,

the third compressive load is less than 10 lbf±1 lbf, and

the tensile load is 810 lbf±100 lbf.

14. The apparatus of claim 9 , wherein:

the latch hook is configured to rotate about a first pivot, and

the magnitude of the first compressive load is multiplied by the ratio of the shortest distance C between the first pivot and the peak magnitude vector of the first compressive load to the shortest distance D between the first peak magnitude vector and the first pivot as it is transferred to the first contact zone by the latch hook.

15. The apparatus of claim 14 , wherein the ratio is less than one.

16. The apparatus of claim 9 , wherein:

the lever arm component is a third-class lever configured to pivot about the fulcrum.

17. The apparatus of claim 1 , further comprising:

a radial alignment feature pair including a concave conic surface and a complementary convex conic surface; and

two or more linear alignment feature pairs, each linear alignment feature pair including a concave prismatic surface and a complementary convex prismatic surface, wherein:

one of the concave conic surface and the convex conic surface is located on the first member and the other of the concave surface and the convex conic surface is located on the second member such that the concave conic surface and the convex conic surface contact one another when the first member and the second member are in the hinge-closed state,

one of the concave prismatic surface and the convex prismatic surface of each linear alignment feature pair is located on the first member and the other of the concave prismatic surface and the convex prismatic surface of the linear alignment feature pair is located on the second member such that the concave prismatic surface and the convex prismatic surface of each linear alignment feature pair contact one another when the first member and the second member are in the hinge-closed state, and

the concave prismatic surface and the convex prismatic surface of each linear alignment feature pair contact each other along surfaces that bracket an axis that passes through the center axis of the concave conic surface when the first member and the second member are in the hinge-closed state.

18. The apparatus of claim 17 , wherein, when the first member and the second member are in the hinge-closed state and the tensile load is induced in the latch link and the latch hook, the tensile load:

(a) draws the convex conic surface and the concave conic surface of the radial alignment feature pair into contact with one another, and

(b) draws the convex prismatic surface and the concave conic surface of each linear alignment feature pair into contact with one another.

19. The apparatus of claim 18 , wherein:

the hinge pivot includes a radial clearance gap between portions of the hinge pivot that define a rotatable bearing interface provided by the hinge pivot,

there is load transferred between the first member and the second member through the hinge pivot as the first member and the second member transition from the hinge-open state to the hinge-closed state, and

there is no load transferred between the first member and the second member via the hinge pivot when the tensile load in the latch link and the latch hook is present.

20. The apparatus of claim 1 , further comprising:

a spacecraft; and

an extensible equipment boom configured to be transitioned between a stowed state and a deployed state, wherein:

the latching hinge connects the extensible equipment boom with the spacecraft,

the latching hinge is in the hinge-open state when the extensible equipment boom is in the stowed state, and

the latching hinge is in the hinge-closed state when the extensible equipment boom is in the deployed state.