FIELD OF THE INVENTION

[0001] The present invention generally relates to a stored energy release triggered by a piezoelectric element, and more particularly to a stored energy release incorporated within a water activated release system (WARS).

BACKGROUND

[0002] Water activated release systems (WARS) are known in the art and are typically configured to trigger release of the WARS from a restraint, such as a harness, once the system is submersed in seawater. To that end, the WARS may include sensors which, when submersed in seawater, detect a change in resistance due to the salinity of the seawater. Upon sensing a threshold salinity/drop in resistance, a capacitor is charged via a battery pack so as to discharge a current to a pyrotechnic element and thereby cause the pyrotechnic element to ignite its chemical agents. Firing of the pyrotechnic chemical agents evolves a high pressure gas which actuates locking pins to withdraw into the WARS so as to release the locking pins from the restraint. Other wetting conditions, such as freshwater, fog, rain or humidity will not trigger firing of the pyrotechnic. While pyrotechnic WARS are presently in use, such pyrotechnic systems suffer from high production costs, complex assembly requirements and potential failure due to decomposition or fouling of the pyrotechnic chemical agents.

SUMMARY

[0003] The present invention addresses the above need by providing a WARS without need of a pyrotechnic chemical agent. In an embodiment, a stored energy release comprises an actuatable member slidably received within a housing. The actuatable member has an extended orientation wherein a portion of the actuatable member extends outwardly from the housing and a retracted orientation wherein the actuatable member resides within the housing. A biasing member is located between the actuatable member and the housing and biases the actuatable member to the retracted orientation. A shaft is within the housing with the actuatable member configured for sliding movement along the shaft. A retaining member is located between the actuatable member and the shaft and maintains the actuatable member in the extended orientation whereby potential energy is stored within the biasing member. A piezoelectric element selectively engages the retaining member to disable the retaining member and release the stored potential energy within the biasing member to place the actuatable member in the retracted orientation.

[0004] In a further aspect of the present invention, the actuatable member includes a pin puller coupled to a locking pin whereby the locking pin is configured to extend outwardly from the housing when the actuatable member is in the extended orientation. The shaft may also include a shoulder with the retaining member configured to engage the shoulder when the piezoelectric element is in a first state and wherein the retaining member disengages the shoulder when the piezoelectric element is in a second state such that the actuatable member is biased to the retracted orientation. The shaft may alternatively include tapered ends while the retaining member includes a ring configured to engage the tapered end when the piezoelectric element is in the first state and wherein the ring disengages the tapered end when the piezoelectric element is in a second state such that the actuatable member is biased to the retracted orientation.

[0005] In another aspect of the present invention, a water activated release system configured to automatically uncouple an occupant worn harness from a link when immersed in salt water comprises a body having a first end coupled to either the occupant worn harness of the link and a second end coupled to the other of the occupant worn harness of the link. The first end includes a power supply and at least one sensor in communication with an electronics package assembly (EPA) having an internal circuit with activated and deactivated states. The at least one sensor is configured to sense when the WARS is immersed in salt water and trigger the EPA to the activated state. The second end includes a stored energy release assembly comprising an actuatable member slidably received within a housing. The actuatable member has an extended orientation wherein a portion of the actuatable member extends outwardly from the housing to couple the WARS to the link and a retracted orientation wherein the actuatable member resides within the housing to uncouple the WARS from the link. A biasing member is located between a portion of the actuatable member and the housing. The biasing member is configured to bias the actuatable member to the retracted orientation. A shaft is within the housing with the actuatable member configured for sliding movement along the shaft. A retaining member is located between the actuatable member and the shaft. The retaining member is configured to maintain the actuatable member in the extended orientation whereby potential energy is stored within the biasing member. A piezoelectric assembly is configured to receive electrical power from the power supply when the EPA is triggered to the activated state. The piezoelectric assembly includes a piezoelectric element configured to selectively engage the retaining member to disengage the retaining member from the shaft and release the stored potential energy within the biasing member to bias the actuatable member to the retracted orientation whereby the occupant worn harness is uncoupled from the link.

[0006] In still another aspect of the present invention, the link is further coupled to a parachute riser or an overhead reel and the power supply is one or more batteries. Also, the at least one sensor is configured to detect a change in resistance due to the salinity of the salt water.

[0007] These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF DRAWINGS

[0008] For a more complete understanding and appreciation of this invention, and its many advantages, reference will be made to the following detailed description taken in conjunction with the accompanying drawings.

[0009] FIG. 1 is an environmental view of a harness system including a water activated release system in accordance with the present invention;

[0010] FIG. 2 is an isolated view of the water activated release system shown in FIG. 1;

[0011] FIG. 3 is a cross section view of a prior art pyrotechnic water activated release system with the pyrotechnic in an unfired condition and locking pins extended;

[0012] FIG. 4 is a cross section view of the prior art pyrotechnic water activated release system shown in FIG. 3 following firing of the pyrotechnic and retraction of the locking pins;

[0013] FIG. 5 is a cross section view of a piezoelectric water activated release system in accordance with an aspect of the present invention;

[0014] FIG. 6 is a cross section view of an isolated piezoelectric assembly within the piezoelectric water activated release system shown in FIG. 5;

[0015] FIG. 6A is an expanded view of a pin holder and dowel within the piezoelectric assembly shown in FIG. 6;

[0016] FIG. 7 is an isolated, front cross section view of the pin holder and piezoelectric element within the piezoelectric assembly shown in FIG. 6; [0017] FIG. 8 is a cross section view of the piezoelectric water activated release system shown in FIG. 5 with the locking pins manually placed within the retracted orientation;

[0018] FIG. 9 is a cross section view of the piezoelectric water activated release system shown in FIG. 5 following actuation of the piezoelectric element and retraction of the locking pins.

[0019] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate currently preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION

[0020] FIG. 1 shows an exemplary environmental view of a harness configuration 10 which may suitably include a water activated release system (WARS). Harness configuration 10 may include a first strap 12 fixedly secured to a first end 14 of a manual release mechanism 16. First strap 12 may, for example, be secured to an occupant- worn harness system, such as but not limited to a parachute harness. The opposing second end 18 of manual release mechanism 16 may include a clasp 20 configured to receive a link 22. Pivoting clasp 20 enables release of link 22 from manual release mechanism 16. Link 22 may be coupled to a second strap 24. Second strap 24 may be secured to a further structure, such as an overhead reel (not shown) or may be a parachute riser of a parachute. In one instance, link 22 may be directly coupled to second strap 24 via pin 26 whereby second strap 24 would be released from first strap 12 only upon actuation of clasp 20 of manual release mechanism 16.

[0021] With additional reference to FIG. 2, to provide for increased safety, particularly in those applications anticipated to occur on, near or over seawater, WARS 28 may be interposed between strap 24 and link 22. In this instance, pin 26 is fixedly secured within openings 30 defined within lobes 31 which extend outwardly from first end 32 of body 29 of WARS 28. Second end 34 of WARS 28 may include opposing locking pins 36 configured to be releasably coupled to link 22. In this manner, upon submersion in seawater, WARS 28 may be activated to retract locking pins 36 and thereby disengage locking pins 36 from link 22. First strap 12 may then be decoupled from second strap 24 whereby the occupant is released from the overhead reel or parachute riser and canopy. [0022] With attention to FIGS. 3 and 4, a prior art pyrotechnic WARS is generally indicated by reference number 28a. As can be seen, pyrotechnic WARS 28a includes a body 29a having opposing locking pins 36a slidably received within a channel 38a defined within second end 34a. Locking pins 36a are biased outwardly of second end 34a, such as by way of spring 40a so as to engage link 22. First end 32a of WARS 28a may be include sensors 42a configured to sense when WARS 28a is submersed within seawater, such as by a change in resistance between the sensors. Sensors 42a may communicate with an electronics package assembly (EPA) 44a whereby, when sensors 42a indicate seawater submersion, EPA 44a may close a circuit to charge capacitor 45a. Electrical power may be provided to sensors 42a, EPA 44a and capacitor 45a by one or more button cells 46a. Upon charging of capacitor 45a, a discharge current may then be directed to pyrotechnic element 48a so as to fire the pyrotechnic chemical agent contained therein and thereby generate a gas. The gas may then travel through gas path 50a and exert a force against head 37a of each locking pin 36a. The force exerted by the gas is sufficient to overcome the biasing force of spring 40a whereby locking pins 36a are driven inwardly within channel 38a. Channel 38a may further include a ramped surface 52a whereby, when driven by the evolved gas, heads 37a may be wedged against ramped surface 52a such that locking pins 36a may not be biased outwardly by spring 40a following a drop in gas pressure. In this manner, WARS 28a may then be freely removed from link 22 as shown in FIG. 4.

[0023] Turning now to FIGS. 5-9, an embodiment of a piezoelectric WARS 28b generally includes a body 29b having first and second ends 32b, 34b, respectively. It should be noted that first end 32b has been omitted from FIGS. 6, 8 and 9 for purposes of clarity. With reference to FIG. 5, first end 32b of WARS 28b may include sensors 42b configured to sense when WARS 28b is submersed within seawater. Sensors 42b may communicate with EPA 44b, when sensors 42b indicate seawater submersion. EPA 44b may then close a circuit to provide electrical power to piezoelectric assembly 35b, which will be discussed in greater detail below. Electrical power may be provided by one or more button cells 46b.

[0024] Second end 34b may include a piezoelectric assembly 35b within channel 38b defined within the housing of second end 34b. Piezoelectric assembly 35b may comprise opposing locking pins 36b each biased outwardly from second end 34b, such as by way of a respective conical spring 40b acting against a respective retaining member, such as holder 54b. Each holder 54b abuts a respective shoulder 56b defined by central shaft or dowel 58b (FIGS. 6 and 6A). Piezoelectric assembly 35b may further include a respective pin puller 60b coupled to flanged end 62b of a respective locking pin 36b at a first end 64b. Together, each locking pin 36b and associated pin puller 60b may be referred to as an actuatable member. Opposing second end 66b of pin puller 60b includes a flange 68b. Inner surface 70b of flange 68b engages holder 54b while outer surface 72b is configured to engage a biasing member, such as wave spring 74b. The opposing end of each wave spring 74b seats against wall 76b of second end 34b such that wave spring 74b imparts an inward biasing force against pin puller 60b, and thus locking pins 36b. Potential energy is stored within each wave spring 74b and inward travel of locking pins 36b is prevented by engagement of holder 54b with shoulder 56b.

[0025] FIG. 7 is an isolated view of a holder 54b. Holder 54b may include a generally C- shaped member 77b defining a narrow gap 78b and central opening 80b. A piezoelectric element 82b may extend across gap 78b. Piezoelectric element 82b may be initially configured to be in a compressed state while central opening 80b is proportioned such that its diameter D is substantially equal to the outer diameter of reduced portion 84b of central dowel 58b (see FIG. 6A) but less than the outer diameter of unreduced portion 86b of central dowel 58b. In this manner, piezoelectric element 82b may clamp holder 54b to reduced portion 84b of central dowel 58b and thereby prevent inward travel of holder 54b when under the biasing force of wave spring 74b as described above. However, following a sensed seawater submersion, discharge of capacitor 45b may cause expansion of piezoelectric element 82b. As a result, C-shaped member 77b may be deformed radially outward such that diameter D of central opening 80b may be expanded to be at least equal to the outer diameter of unreduced portion 84b of central dowel 58b. C-shaped member 77b may further include a hinge point, such as recess 88b, configured to assist control of the radially outward expansion of C-shaped member 77b. In this manner, and as shown in FIG. 9, holder 54b may translate linearly inward within channel 38b as the potential energy stored within wave springs 74b is released. As pin puller 60b is coupled to wave spring 74b, and locking pin 36b is coupled to pin puller 60b, locking pin 36b also translates inwardly within channel 38b such that locking pin 36b lies below plane P defined by the terminus of second end 34b. As a result, WARS 28b may be decoupled from link 22 as described above.

[0026] With reference to FIG. 8, WARS 28b may be manually coupled to link 22 without the use of tools. As shown in FIG. 8, locking pins 36b may be manually directed into second end 34b upon compression of conical springs 40b. Inward travel of holder 54b is prevented by engagement of C-shaped member 77b with shoulder 56b as described above. In this manner, WARS 28b may slide within link 22. With WARS 28b properly in place, compression of conical springs 40b is removed such that stored potential energy within conical springs 40b drives locking pins 36b outwardly such that locking pins 36b may engage link 22 so as to releasably couple WARS 28b to first strap 12.

[0027] It should be understood the steps of the method presented herein do not necessarily have to be in the order in which it is presented. It is also understood that when an element is referred to as being "on", "connected to/with", or "coupled to/with" another element, the element can be directly on, connected to/with or coupled to/with the other element or intervening elements may also be present.

[0028] While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements or components thereof to adapt to particular situations without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the following claims.