Passive safety mechanism utilizing self-fracturing shape memory material

Patent metadata

Field	Value
Publication number	US-9334675-B2
Application number	US-201213586188-A
Country	US
Kind code	B2
Filing date	Aug 15, 2012
Priority date	Aug 15, 2012
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A system includes a structure having a first structural element and a second structural element. The system also includes a latch configured to releasably secure the first structural element to the second structural element. The latch includes first and second portions. The latch also includes a ball lock configured to hold the first and second portions of the latch together when the ball lock is engaged. The ball lock is also configured to allow the first and second portions of the latch to separate when the ball lock is disengaged. The latch further includes a shape memory material member configured to fracture when exposed to an elevated temperature and thereby disengage the ball lock. The shape memory material member could include an elongated structure that is configured to decrease in length when exposed to the elevated temperature. The elongated structure could have at least one notch.

First claim

What is claimed is:

1. An apparatus comprising:
a latch comprising:
a first portion comprising a recess;
a second portion comprising a projection configured to fit within the recess;
a ball lock comprising at least one ball, the ball lock configured to hold the first and second portions of the latch together when the ball lock is engaged and to allow the first and second portions of the latch to separate when the ball lock is disengaged, wherein the ball lock is configured to (i) engage the first and second portions of the latch by holding the at least one ball in at least one opening of the projection while the projection is within the recess when the ball lock is engaged and (ii) disengage from at least one of the first portion or the second portion of the latch when the ball lock is disengaged; and
a shape memory material member connected to at least one of the first and second portions of the latch, the shape memory material member configured to fracture when exposed to an elevated temperature and thereby disengage the ball lock.

2. The apparatus of claim 1 , wherein:
the at least one ball is configured to fit within the recess in the first portion of the latch; and
the latch further comprises a pin configured to:
extend through at least part of the second portion of the latch into the recess in the first portion of the latch, wherein the at least part of the second portion of the latch includes the projection; and
retain the at least one ball within the recess in order to engage the ball lock.

3. An apparatus comprising:
a latch comprising:
a first portion;
a second portion;
a ball lock configured to hold the first and second portions of the latch together when the ball lock is engaged and to allow the first and second portions of the latch to separate when the ball lock is disengaged, wherein the ball lock is configured to (i) engage the first and second portions of the latch when the ball lock is engaged and (ii) disengage from at least one of the first portion or the second portion of the latch when the ball lock is disengaged; and
a shape memory material member connected to at least one of the first and second portions of the latch, the shape memory material member configured to fracture when exposed to an elevated temperature and thereby disengage the ball lock;

wherein:
the ball lock comprises at least one ball configured to fit within a recess in the first portion of the latch;
the latch further comprises a pin configured to extend through at least part of the second portion of the latch into the recess in the first portion of the latch, the pin also configured to retain the at least one ball within the recess in order to engage the ball lock;
the second portion of the latch comprises a central body and a holder connected to the shape memory material member, the holder coupled to the central body at a hinge;
the latch further comprises a spring configured to push the pin against the holder;
the holder is configured to rotate away from the pin when the shape memory material member fractures; and
the spring is configured to move the pin out of the recess to disengage the ball lock when the shape memory material member fractures.

4. The apparatus of claim 3 , wherein the latch further comprises:
a first anchor coupled to the holder and to a first end of the shape memory material member; and
a second anchor coupled to a second holder and to a second end of the shape memory material member.

5. The apparatus of claim 1 , wherein:
the shape memory material member comprises an elongated structure; and
the elongated structure is configured to decrease in length when exposed to the elevated temperature.

6. The apparatus of claim 5 , wherein the elongated structure comprises at least one notch that defines a reduced-width portion of the elongated structure.

7. The apparatus of claim 1 , further comprising:
a retainer coupled to the first portion of the latch and configured to couple the latch to an external structure.

8. The apparatus of claim 7 , further comprising:
a handle coupled to the second portion of the latch and configured to cause the latch to raise and lower the retainer.

9. A system comprising:
a structure having a first structural element and a second structural element; and
a latch configured to releasably secure the first structural element to the second structural element, wherein the latch comprises:
a first portion comprising a recess;
a second portion comprising a projection configured to fit within the recess;
a ball lock comprising at least one ball, the ball lock configured to hold the first and second portions of the latch together when the ball lock is engaged and to allow the first and second portions of the latch to separate when the ball lock is disengaged, wherein the ball lock is configured to (i) engage the first and second portions of the latch by holding the at least one ball in at least one opening of the projection while the projection is within the recess when the ball lock is engaged and (ii) disengage from at least one of the first portion or the second portion of the latch when the ball lock is disengaged; and
a shape memory material member connected to at least one of the first and second portions of the latch, the shape memory material member configured to fracture when exposed to an elevated temperature and thereby disengage the ball lock.

10. The system of claim 9 , wherein:
the at least one ball is configured to fit within the recess in the first portion of the latch; and
the latch further comprises a pin configured to:
extend through at least part of the second portion of the latch into the recess in the first portion of the latch, wherein the at least part of the second portion of the latch includes the projection; and
retain the at least one ball within the recess in order to engage the ball lock.

11. A system comprising:
a structure having a first structural element and a second structural element; and
a latch configured to releasably secure the first structural element to the second structural element, wherein the latch comprises:
a first portion;
a second portion;
a ball lock configured to hold the first and second portions of the latch together when the ball lock is engaged and to allow the first and second portions of the latch to separate when the ball lock is disengaged, wherein the ball lock is configured to (i) engage the first and second portions of the latch when the ball lock is engaged and (ii) disengage from at least one of the first portion or the second portion of the latch when the ball lock is disengaged; and
a shape memory material member connected to at least one of the first and second portions of the latch, the shape memory material member configured to fracture when exposed to an elevated temperature and thereby disengage the ball lock;

wherein:
the ball lock comprises at least one ball configured to fit within a recess in the first portion of the latch;
the latch further comprises a pin configured to extend through at least part of the second portion of the latch into the recess in the first portion of the latch, the pin also configured to retain the at least one ball within the recess in order to engage the ball lock;
the second portion of the latch comprises a central body and a holder connected to the shape memory material member, the holder coupled to the central body at a hinge;
the latch further comprises a spring configured to push the pin against the holder;
the holder is configured to rotate away from the pin when the shape memory material member fractures; and
the spring is configured to move the pin out of the recess to disengage the ball

Assignees

• Koehler Frederick B
• Lyman Ward D
• Raytheon Co

Inventors

• Koehler Frederick B
• Lyman Ward D

Classifications

• F03G7/0631

  One-way operation, e.g. release mechanism · CPC title

• F03G7/0614 Primary

  using shape memory elements · CPC title

• E05B47/0009

  with thermo-electric actuators, e.g. heated bimetals · CPC title

• E05B65/104

  actuated in response to heat, e.g. with fusible element, bimetal, memory shape or swelling material · CPC title

• E05B51/005

  by a bimetallic or memory-shape element (heated by electricity E05B47/0009; for panic door actuation E05B65/104) · CPC title