In the accompanying drawings, which are incorporated in and constitute a part of the specification, embodiments of the invention are illustrated, which, together with the detailed description given below, serve to exemplify embodiments of the invention:
While various aspects and concepts of the invention are described and illustrated herein as embodied in combination in the embodiments, these various aspects and concepts may be realized in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present invention. Still further, while various alternative embodiments as to the various aspects and features of the invention, such as alternative materials, structures, configurations, methods, devices, and so on may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or identified herein as conventional or standard or later developed. Those skilled in the art may readily adopt one or more of the aspects, concepts or features of the invention into additional embodiments within the scope of the present invention even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the invention may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, or representative values and ranges may be included to assist in understanding the present invention however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated.
For the purposes of this application, the terms attach (attached), connect (connected), and link (linked) are not limited to direct attachment, connection, or linking but also include indirect attachment, connection, or linking with intermediate parts, components, or assemblies being located between the two members being attached, connected, or linked to one another. Furthermore, positional terms such as upper, lower, top, bottom, upward, downward, horizontal, and vertical are merely references used herein for convenience of explanation when referring to the Figures and form no structural or use limitation or reference for the device.
The amount of force or load exerted on the SMA wire(s) can shift/raise/lower the transition temperature at which the state changes occur. A higher stress load on the SMA wire(s) increases the start and finish temperatures of both transitions. Thus, the transition temperatures at a higher constant stress are greater than the transition temperatures at the lower constant stress. Therefore, changing the amount of stress on the SMA wire(s) impacts the temperatures at which the wire(s) transition between states.
Referring again to
The device 100 includes a first source 124 of work/force and/or a linkage or component for transferring force from a first source of work/force to the SMA wire(s) 14. In other words, the device may include a first source of force that acts on the SMA wire(s) or the device may include a means for receiving and transferring an external force to the wire(s). The first source 124 may be configured in a variety of ways. Any source of force capable of applying a tensile load to the SMA wire(s) that is sufficient to stretch the wire(s) and move the first moveable member 102 to the first position may be used. In the depicted embodiment, for example, the first force source 124 may be a bias element such as, but not limited to, a spring. When the electric current is removed from the SMA wire(s) 104, the SMA wire(s) may cool down to the martensite transition temperature and change state from austenite to martensite. Once the SMA wire(s) 104 returns to the martensite state, the tensile force being applied from the first force source 124 stretches the SMA wire(s) and returns the first movable member 102 to the first position; thus, resetting the device.
The device 100 also includes a second source 126 of work/force and/or linkage or component for transferring force from the second force source to the SMA wire(s) 104. The second source 126 is adapted to stress induce the SMA wires(s) 104 to change state to the martensite. The second force source 126, as with the first force source 124, may be configured in a variety of ways. Any source of force capable of applying a tensile load to the SMA wire(s) that is sufficient to stress induce a state change to martensite in the SMA wires(s) may be used. In the depicted embodiment, for example, the second force source is external to the device, such as person manually applying a force that is transmitted to the SMA wire(s) through a linkage.
When the electric current is removed from the SMA wire(s) 104, if the ambient temperature surrounding the device 100 is high enough that the SMA wire(s) does not cool down to the martensite transition temperature, the device is configured to stress induce the state change in the SMA wire(s). The force from the second source 126 induces a state change in the SMA wire(s) and alone or in conjunction with the force from the first source 124, stretches the SMA wire(s) and returns the first movable member 102 to the first position; thus, resetting the device.
The device 100, therefore, electrically actuates and utilizes force from a first source to reset the device when the temperature of the SMA wire(s) is below a certain value and utilizes force from a second source to reset the device when the temperature of the SMA wire(s) is at or above the value. Thus, even when the SMA wire(s) is hotter than its martensite transition temperature, the device may operate effectively by utilizing a higher load to stress induce the state change to martensite.
Referring to
The movable member 202 may be configured in a variety of ways. Any structure capable of linking the SMA wire(s) 204 to one or more sources of force may be used. In the depicted embodiment, the movable member 202 is configured as a generally rectangular component having a slot 214 extending along a portion of its length and a coupling portion 216 situated on an extending arm 218. The coupling portion 216 may be configured in a variety of ways. Any structure capable of temporarily coupling with another component of the device 200 may be used. In the depicted embodiment, the coupling portion 216 is configured as a hook or barb (see
The first movable member 202 includes an opening 220 that serves as an attachment point for the SMA wire(s) 204. In addition, a coil spring or other bias element (not shown) may be disposed between the housing 206 and the first movable member 202 to bias the first movable member toward the first position. In the embodiment of
The SMA actuated device 200 also includes a second movable member 224 realized as a pawl and a third movable member 226 realized as a ratchet. The pawl 224 and ratchet 114 may be configured in a variety of ways. Any structure that may cooperate to receive and hold a door striker 210 may be used. In the depicted embodiment, the pawl 224 in generally U-shaped structure that is pivotally mounted to the housing 206 at a pivot point 228. The pawl 224 has a first arm 230 and a second arm 232. The first arm 230 has a pin 234 at its distal end that is received within the slot 214 on the first movable member 202. The pawl 224 and the first movable member 202, however, may be connected in any suitable manner.
The pawl 224 also includes a portion for interfacing with the ratchet 226. The portion may be configured in a variety of ways. Any structure capable of interfacing with the ratchet to restrict movement of the ratchet may be used. In the depicted embodiment, the portion is configured as a projection 236 extending outward from the first arm 230 toward the ratchet 226.
A torsion spring (not shown) may be disposed between the housing 206 and the pawl 224 to bias the pawl toward the ratchet 226 (i.e. in a counter-clockwise direction as illustrated in
The ratchet 226 is pivotally mounted to the housing 206 at a pivot point 238. The ratchet 226 includes a recess 240, a surface 242 for interfacing with the pawl 224, and an engagement portion 244 for interfacing with the movable member 202, realized in the depicted embodiment as a hook or barb for interfacing with the movable member 202. A torsion spring (not shown) may be disposed between the housing 206 and the ratchet 226 to bias the ratchet to an open position (i.e. in a clockwise direction as illustrated in
An electric power source (not shown), such as for example, a battery, is in circuit communication with the SMA wire(s) 204 in a maimer that allows the power source to send an electric current through the SMA wire(s). A control unit may control the application of the electric current through the SMA wires(s).
When an electric current is passed through the SMA wire(s) 204, the wire(s) heats up above its austenite transition temperature and contracts (i.e. changes to the austenite state). As shown in
As shown in
Referring to
If, however, the ambient temperature surrounding the device 200 were high enough that the SMA wire(s) 204 does not cool to the martensite transition temperature, the device is configured to stress induce a state change in the SMA wire(s). Referring again to
The device 200, therefore, electrically actuates and utilizes a force from a first source (e.g. the bias element between the housing and the first movable member) to reset the device when the temperature of the SMA is below a certain amount (e.g. the martensite transition temperature) and utilizes a force from a second source (e.g. a user closing the door) to reset the device when the temperature of the SMA is at or above the amount. Thus, even when the SMA wire(s) is hotter than its martensite transition temperature, and may be unable to cool due to higher ambient conditions, the device may operate effectively by utilizing a higher load to stress induce the state change to martensite.
Referring to
The pawl 324 and ratchet 326 may be configured in a variety of ways. Any structure that may cooperate to receive and hold a door striker may be used. In the depicted embodiment, the pawl 324 in generally U-shaped structure that is pivotally mounted to the housing 306 at a pivot point 328. The pawl 324 has a first arm 330 and a second arm 332. The first arm 330 has an attachment point 320 for the first SMA wire(s) 304 to attach to the first arm. The second arm 318 has an attachment point 322 for the second SMA wire(s) 305 to attach to the second arm.
A coil spring, torsional spring or other bias element (not shown) may be disposed between the housing 306 and the pawl 324 to bias the pawl toward the first position (i.e. in a counter-clockwise direction as illustrated in
The pawl 324 includes portion for interfacing with the ratchet 326. The portion may be configured in a variety of ways. Any structure capable of interfacing with the ratchet 326 to restrict movement of the ratchet may be used. In the depicted embodiment, the portion is configured as a projection 336 extending outward from the first arm 330 toward the ratchet 326.
The ratchet 326 pivotally mounts to the housing 306 at a pivot point 338. The ratchet 326 includes a recess 340 for receiving the striker 310 and a surface 342 for interfacing with the pawl 324. A torsion spring (not shown) is disposed between the housing 306 and the ratchet 336 to bias the ratchet to an open position (i.e. in a clockwise direction as illustrated in the
An electric power source (not shown), such as for example, a battery, is in circuit communication with the first SMA wire(s) 304 and the second SMA wire(s) 305 in a manner that allows the power source to selectively send an electric current through the first SMA wire(s) 304 or the second SMA wire(s) 305. Separate power sources may be used for each of the SMA wires or a single source/circuit capable of sending a current to each of the SMA wires selectively, may be used. A control unit may control the application of the electric current through the SMA wires(s).
When an electric current passes through the first SMA wire(s) 304, the first SMA wire(s) heats up above its austenite transition temperature and contracts (i.e. changes to the austenite state). As shown in
Referring to
If, however, the ambient temperature surrounding the device 300 is high enough that the first SMA wire(s) 304 does not cool to the martensite transition temperature, the device 300 is configured to stress induce a state change in the first SMA wire(s). The second SMA wire(s) 305 is configured to provide sufficient force on the pawl 324 when it contracts (i.e. changes state to austenite) to stress induce a state change in the first SMA wire(s) 304. Thus, when an electric current passes through the second SMA wire(s) 305, the second SMA wire(s) contracts and pivots the pawl 324 back to the position illustrated in
The device 300, therefore, electrically actuates and utilizes a force from a first source (e.g. a bias element between the housing and the pawl) to reset the device when the temperature of the SMA is below a certain value (e.g. the martensite transition temperature) and utilizes a force from a second source (e.g. a electronically actuated second SMA wire(s)) to reset the device when the temperature of the SMA is at or above the value. Thus, even when the SMA wire(s) is hotter than its martensite transition temperature, and may be unable to cool due to higher ambient conditions, the device may operate effectively by utilizing a higher load to stress induce the state change to martensite.
The device 400 includes a housing 406 configured to mount adjacent a door by any suitable means, such as fasteners for example. Disposed within the housing 406 is a first movable member 402 that connects to at least one SMA wire(s) 404. The first movable member 402 pivotally mounts to the housing 406 at a pivot point 408 and is movable between a first position and a second position.
The first movable member 402 may be configured in a variety of ways. Any structure capable of linking the SMA wire(s) 404 to one or more sources of force and interfacing with a door may be used. In the depicted embodiment the first movable member 402 is configured as a striker for engaging a portion of a door 410 to hold the door in a closed position.
The first movable member 402 includes a first attachment point 412 used to attach to the SMA wire(s) 404 and a second attachment point 414 used to attach to a first source of force, realized in the depicted embodiment, as a biasing element 416 such as a coil spring. The biasing element 416 is disposed between the housing 406 and the first movable member 402 to bias the first movable member toward the first position. The biasing element 416 and the SMA wire(s) 404 may attach in any suitable manner. In the depicted embodiment, the biasing element 416 is attaches to the housing 406 at a pin 418 and attaches to the first movable member 402 at the second attachment point 414 realized as an opening. The first movable member 402 also includes an engagement surface 422 (see
The device 400 also includes a second movable member 424. The second movable member 424 may be configured in a variety of ways. Any device capable transferring force to the shape memory alloy wire(s) 404 from a second source of force may be used. In the depicted embodiment, the second movable member 424 is a reset cam adapted to transfer force from the door 410, through the first movable member 402 and to the SMA wire(s) 404 to induce a state change in the SMA wire(s). The cam 424 is a generally an L-shaped structure having a first arm 426 extending generally perpendicular to a second arm 428. The first arm 426 includes a projection or pin 430 at its distal end. The cam 424 is slideably received in an angled groove 432 in the housing 406 (best viewed in
A bias element (not shown), such as a coil spring, biases the cam 424 toward the second position (upward as illustrated in
Referring to
Referring to
Referring to
Referring to
If, however, the ambient temperature surrounding the device 400 is high enough that the SMA wire(s) 404 does not cool to the martensite transition temperature, the device 400 is configured to stress induce a state change in the first SMA wire(s). When the second movable member 424 is in the second position, the pin 430 is in a position adjacent the first movable member 402 and engageable with the first movable member, due to the angle of the groove 432. As the door 410 is closed by a second source of force, such as for example, a user, the door engages the second arm 428 of the second movable member 424 forcing the second movable member back to its first position. As the second movable member 424 moves to the first position, the pin 430 engages the first movable member 402 and forces the first movable member to its first position. As a result, the force from the second source is transferred through the second movable member 424 to stress induces a state change in the SMA wire(s) 404 and stretches the SMA wires(s) out.
The device 400, therefore, electrically actuates and utilizes a force from a first source (e.g. a bias element 416) to reset the device when the temperature of the SMA is below a certain amount (e.g. the martensite transition temperature) and utilizes a force from a second source (e.g. an end user closing the door) to reset the device when the temperature of the SMA is at or above the amount. Thus, even when the SMA wire(s) is hotter than its martensite transition temperature, and may be unable to cool due to higher ambient conditions, the device may operate effectively by utilizing a higher load to stress induce the state change to martensite.
The device 500 includes a first movable member 502 that connects to at least one SMA wire(s) 504. The first movable member 502 is movable between a first vertical position and a second vertical position. The first movable member 502 is biased toward the first position (downward in the Figures) by a first force source 506 realized as a bias element, such as, but not limited to, a spring. The first movable member 502 may be configured in a variety of ways. Any structure capable of linking the SMA wire(s) 504 to one or more sources of force may be used. In the depicted embodiment the first movable member 502 is configured as a generally rectangular component having a first coupling portion 508 for attaching to the SMA wire(s) and a second coupling portion 510 for connecting to a second movable member 512. The first coupling portion 508 is realized as a projection or pin extending from the first movable member 502 to engage the SMA wire(s) 504 at a point along the length of the wire(s). The second coupling portion 510 is realized as a projection or pin extending from the first movable member 502 to engage the second movable member 512.
The second movable member 512 is movably attached to the first movable member 502 and is movable between a first horizontal position and a second horizontal position. The second movable member 512 may be configured in a variety of ways. In the depicted embodiment, the second movable member 512 is realized as a door lock slide having a body portion 514 and an engagement portion 516 realized as a latch for engaging a door frame or strike plate. The body portion 514 is generally rectangular and includes a guide path or groove 520 that receives the pin 510 of the first movable member 502. The path 520 has a lower section 522 that extends generally parallel to an upper section 524. A generally linear side section 526 connects the upper and lower sections 522, 524 at a first end of the path, and a generally curved side section 528 connects the upper and lower sections at a second end of the path.
At the intersection between the generally linear side section 526 and the upper section 524 is a first one-way door 530 and at the intersection between the generally curved side section 528 and the upper section 524 is a second one-way door 532. The first and second one-way doors 530, 532 allow the pin 510 to pass the doors in only one direction (illustrated as clockwise in
The second movable member 512 is biased toward the second position (to the right as illustrated in
Referring to
Referring to
Referring to
Referring to
Referring to
In the embodiments described herein, the SMA material selected for the SMA members(s) may be any suitable SMA, such as for example, nitinol. Flexinol®, which are registered trademarks of Dynalloy, Inc., has been found to be a suitable SMA. Other SMA materials, however, may be used and may be selected to provide different temperature actuation ranges, based on availability, or for any other reason without departing from the spirit and scope of the invention. Other SMAs materials include, but are not limited to, copper/zinc/aluminum, copper/aluminum/nickel, silver/cadmium, gold/cadmium, copper/tin, copper/zinc, indium/titanium, nickel/aluminum, iron/platinum, manganese/copper, iron/manganese/silicon, nickel/titanium/hafnium, nickel/titanium/palladium, and other nickel/titanium alloys.
The invention has been described with reference to the preferred embodiments. Modification and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
This application claims priority to, and ay other benefit of, U.S. Provisional Patent Application Ser. No. 60/832,933 filed Jul. 25, 2006, for SHAPE MEMORY ALLOY (SMA) ACTUATED DEVICE CAPABLE OF EASILY OPERATING AT AMBIENT TEMPERATURES EQUAL TO OR GREATER THAN 80° C., the entire disclosure of which is fully incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
60832933 | Jul 2006 | US |