U.S. patent application number 12/938414 was filed with the patent office on 2011-06-16 for stud fastener and stabilising device.
Invention is credited to LEE DAVID BLATTMAN, LACHLAN RICHARD GOLDSPINK, DICKORY RUDDUCK.
Application Number | 20110142570 12/938414 |
Document ID | / |
Family ID | 37073006 |
Filed Date | 2011-06-16 |
United States Patent
Application |
20110142570 |
Kind Code |
A1 |
RUDDUCK; DICKORY ; et
al. |
June 16, 2011 |
Stud Fastener and Stabilising Device
Abstract
The invention relates to a stabilizing device (120) for an
assembly which includes two shape memory alloy wires (104, 106)
adapted to operate in conjunction. The stabilizing device (120)
includes a rocker plate (108) for attachment to each of the shape
memory alloy wires; the rocker plate (108) is adapted to pivot when
one shape memory alloy wire (104 or 106) is subjected to a stress
greater than that to which the other shape memory alloy wire (106
or 104) is subjected, in order to reduce the stress on the first
mentioned shape memory alloy wire. The invention further relates to
a fastener (60) including a stud (54) having a locking cavity (56),
an aperture (58) adapted to receive the stud (54), a locking means
(teeth) (620) adapted to engage the locking cavity (56), a shuttle
(66) rotatable by rotating means including material adapted to
contract when activated and a plug (87) slidable within the shuttle
(66) to close off the aperture (58) when not occupied by the stud
(54). The shuttle (66) is rotatable by the rotating means between a
locking position, in which the locking means (teeth) (62) engages
the locking cavity (56), and an unlocking position in which the
locking means (teeth) (62) does not engage the locking cavity (56).
The plug (87) can help prevent contamination of the fastener
(60).
Inventors: |
RUDDUCK; DICKORY; (CHICAGO,
IL) ; BLATTMAN; LEE DAVID; (WILMETTE, IL) ;
GOLDSPINK; LACHLAN RICHARD; (WILMETTE, AU) |
Family ID: |
37073006 |
Appl. No.: |
12/938414 |
Filed: |
November 3, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11910702 |
Aug 1, 2008 |
7854580 |
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PCT/AU06/00416 |
Mar 30, 2006 |
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12938414 |
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Current U.S.
Class: |
411/511 |
Current CPC
Class: |
F16B 1/0014 20130101;
F16B 21/186 20130101; F03G 7/065 20130101; Y10S 411/909 20130101;
E05B 47/0009 20130101 |
Class at
Publication: |
411/511 |
International
Class: |
F16B 21/18 20060101
F16B021/18 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 4, 2005 |
AU |
AU2005901640 |
Claims
1. A stabilizing device for an assembly which includes two shape
memory alloy wires adapted to operate in conjunction with each
other, the stabilizing device including a rocker plate for
attachment to each of the shape memory alloy wires, the rocker
plate being adapted to pivot when one shape memory alloy wire is
subjected to a stress greater than that to which the other shape
memory alloy wire is subject, in order to reduce stress on the one
shape memory alloy wire.
2. The device of claim 1, wherein the rocker plate includes a
groove along each of two edges, each groove adapted to act as a
guide for one the shape memory alloy wires.
Description
FIELD OF THE INVENTION
[0001] This invention relates to fastener assemblies and to
stabilising devices. In particular, the invention concerns a stud
fastener with a slidable plug to help prevent contamination of the
fastener mechanism. The invention also concerns a stabilising
device to reduce the stress on shape memory alloy wires of, for
example, a fastener.
BACKGROUND OF THE INVENTION
[0002] In a first aspect, the invention is concerned with a stud
fastener. Stud fasteners are useful in many applications. They can
be used, for example, to close doors, being attached to a door
frame and adapted to receive a stud on a door. A stud fastener can
be used in many other applications. In a second aspect, the
invention is concerned with a stabilising device, especially for
(but not limited to) a fastening assembly which uses shape memory
alloy wires. The stabilising device can operate to reduce the
stress on the shape memory alloy wires.
[0003] Australian Provisional Patent Application No. 2004905399
(the "Provisional Application"), the contents of which are imported
herein by reference, disclosed a fastener including: [0004] a stud
having a locking cavity; [0005] an aperture adapted to receive the
stud; [0006] locking means adapted to engage the locking cavity;
and [0007] a shuttle rotatable by rotating means including material
adapted to contract when activated, the shuttle being rotatable by
the rotating means between a locking position, in which the locking
means engages the locking cavity, and an unlocking position in
which the locking means does not engage the locking cavity.
[0008] One embodiment of the fastener was described in the
Provisional Application and this is an especially preferred
embodiment. A second embodiment was described in connection with
international patent application number PCT/AU2004/000623, the
contents of which are also imported herein by reference. For
convenience, some of the features of the first embodiment are set
out below.
FIRST EMBODIMENT (THE PROVISIONAL APPLICATION)
[0009] The stud may take the form of a pin or peg, with the locking
cavity preferably being a groove around all or part of the stud.
Preferably, the stud in the region of a locking cavity is of
circular cross section, but the invention is not limited to this
embodiment.
[0010] The aperture adapted to receive the stud is preferably of
the same shape as the cross sectional shape of the stud, eg,
circular. The aperture may take any other suitable shape.
[0011] The locking means adapted to engage the locking cavity is
preferably one or more teeth adapted to engage the locking cavity,
such as the groove.
[0012] The shuttle which is rotatable by the rotating means is
rotatable between a locking position in which the locking means
such as the teeth engage the locking cavity, such as the groove,
and an unlocking position in which the locking means do not engage
the locking cavity. The shuttle preferably incorporates means which
engages the locking means in the locking position and which fail to
engage the locking means or which move the locking means out of
engagement with the locking cavity in the unlocking position.
[0013] In a particularly preferred embodiment, the shuttle has one
or more apertures into which the locking means may be received in
the unlocking position. When the locking means, such as teeth, are
not in these apertures, the shuttle is designed to push the locking
means into the locking cavity and hence to the locking
position.
[0014] In another embodiment, the shuttle may include or be
associated with means adapted to engage the locking means and draw
them out of engagement with the locking cavity, when the shuttle is
rotated to the unlocking position.
[0015] The shuttle is rotatable by rotating means which includes
material adapted to contract when activated. Preferably, this
material is shape memory alloy wire, as discussed below. It is
further preferred that the shape memory alloy wire is wound around
the shuttle which is rotatable within a body for the fastener. The
shape memory alloy wire is attached at one end to the shuttle and
at the other to a non-rotatable part of the fastener. When the
shape memory alloy wire is caused to contract by the application of
suitable energy to reach the necessary temperature, the shuttle can
rotate from the locking position to the unlocking position. A
second shape memory alloy wire may be similarly connected to the
shuttle in order to rotate it from the unlocking position to the
locking position.
[0016] Shape memory alloys are known and are usually made
predominantly or wholly of titanium and nickel. They may also
include other material, such as aluminium, zinc and copper. A shape
memory alloy is capable of adopting one shape below a predetermined
transition temperature and changing to a second shape once its
temperature exceeds the transition temperature. Conversely, when
the shape memory alloy cools below the transition temperature, it
is capable of adopting the first shape again.
[0017] Shape memory alloy wire currently available, such as that
sold under the trade mark Nitinol, is capable of contracting by
about 3 percent when activated by heating.
[0018] Activation of the material adapted to contract when
activated is preferably achieved through electrical resistance
heating, with a wire feed to the assembly.
[0019] The fastener of the invention may include lock status
sensors, which can report whether the fastener is in the locked or
unlocked state. Such sensors may act as a reed switch, for example,
so that when they make contact a report is generated that the
fastener is in the locked or unlocked state, depending on the
construction of the fastener. The lock status sensors may also work
by enabling completion of an electrical circuit. Other
configurations and means of sensing may also be applicable.
[0020] The fastener of the invention also preferably includes bias
means, such as a spring, biasing the fastener towards the locked
state. The fastener of the invention also preferably includes an
ejector spring, to assist ejection of the stud when the locking
means is no longer engaged with the locking cavity.
[0021] The fastener of the invention may also include a temperature
sensor for sensing the temperature of the shape memory alloy wire
in the preferred embodiments. This can adjust the amount of energy
applied to the shape memory alloy wire, depending on sensed
temperature, to take into account varying conditions. For example,
if the temperature is relatively low, a larger amount of power may
need to be delivered to the shape memory alloy wire to heat it to
the desired temperature. Conversely, if the temperature is high,
the amount of power to be delivered to the shape memory alloy wire
in order to cause it to contract may be far less. A temperature
sensor can enable feedback and cause adjustment of power delivery
in this regard.
[0022] Optionally, the fastener of the invention has manual
override so that the fastener can be released even if the shuttle
cannot rotate to the unlocking position. A manual override may be
necessary, for example, if there is no power to activate the shape
memory alloy wire, or if the fastener fails for some reason. A
manual override is disclosed in the Provisional Patent Application
and will not be further detailed here.
DISCLOSURE OF THE INVENTION
First Aspect
[0023] It has been found that useful variations may be made to the
fastener described above and these will now be discussed.
[0024] It is preferred that the fastener includes means to relieve
stress on the material adapted to contract when activated, in the
event that the mechanism is jammed or under extreme load.
Preferably, this means takes the form of an overstress spring. This
was disclosed in International Patent Application No.
PCT/AU2004/001580. The contents of this specification are also
imported herein by reference.
[0025] It is preferred that the fastener includes a plug which can
close off the opening of the fastener when in the unlocked state.
Accordingly, this invention provides a fastener including: [0026] a
stud having a locking cavity; [0027] an aperture adapted to receive
the stud; [0028] locking means adapted to engage the locking
cavity; [0029] a shuttle rotatable by rotating means including
material adapted to contract when activated, the shuttle being
rotatable by the rotating means between a locking position, in
which the locking means engages the locking cavity, and an
unlocking position in which the locking means does not engage the
locking cavity; and [0030] a plug slidable within the shuttle to
close off the aperture when not occupied by the stud.
[0031] Preferably, the plug is biased towards the aperture by a
compression spring which also acts to eject the stud when the
locking means is disengaged from the locking cavity of the stud. It
is preferred that the compression spring is longer and more robust
than the spring disclosed in the drawings of the Provisional
Application.
[0032] It is also preferred that the plug provides a fluid-tight
seal when it occupies the aperture, in order to prevent
contamination of the fastener mechanism.
[0033] In the Provisional Application, the inclusion of lock status
sensors was discussed. Lock status sensors can detect if the
fastener is in a locked or unlocked state. An example was given of
a reed switch, but this was not limiting. Optical sensors may also
be used, as another example. Optical sensors can detect if the stud
is retained in the fastener assembly, and if the shuttle is in the
fully locked state. If the fastener were to be only partially
locked--for example, if the shuttle was not fully blocking the
teeth, then the sensors could report this. Optical sensors may have
more durability than mechanical sensors.
[0034] When the material adapted to contract when activated is
shape memory alloy wire, such as Nitinol, it is preferred that the
Nitinol wire is subject to a slightly lower strain during
contraction, in order to enhance life cycles. For example, if the
amount of contraction of the Nitinol wire is changed from 3% to
2.5%, the life cycles of the wire may be as many as 300,000
cycles.
[0035] A torsion spring may be used to rebias the shape memory
alloy wire and to drive the shuttle into the locked position. A
torsion spring may have a lower spring rate than the ring-style
spring discussed in connection with the drawings in the Provisional
Application.
[0036] It is also preferred that, when the fastener includes two
parallel Nitinol wires, a stabilising device is used to ensure that
the two wires share the load, in order to enhance life of the
wires. This aspect of the invention is applicable not only to the
stud fastener of the Provisional Application, but also to various
other assemblies in which two shape memory alloy wires are
used.
DISCLOSURE OF THE INVENTION
Second Aspect
[0037] In a second aspect, this invention provides a stabilising
device for an assembly which includes a first shape memory alloy
wire adapted to operate in conjunction with a second shape memory
alloy wire in the assembly, wherein the stabilising device includes
a rocker plate for attachment to each wire, the rocker plate being
adapted to pivot when one shape memory alloy wire is subjected to a
stress greater than that to which the other shape memory alloy wire
is subject, in order to reduce the stress on the one shape memory
alloy wire.
[0038] An example of the stabilising device is shown in connection
with the drawings, below. Other configurations may be suitable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The invention will now be described in connection with
certain non-limiting examples thereof in connection with the
accompanying drawings, in which:
[0040] FIG. 1 is a perspective view of an embodiment of the first
aspect of the invention, being a stud fastener in the locked
position, with part of the outer body removed and some of the base
on the right hand side omitted;
[0041] FIG. 2 is a side elevation in sectional view of the
embodiment of FIG. 1, with the outer body in place;
[0042] FIG. 3 is a view corresponding to that of FIG. 1, but in the
unlocked position;
[0043] FIG. 4 is a view corresponding to that of FIG. 2, but in the
unlocked position;
[0044] FIG. 5 is a plan view of an embodiment of the second aspect
of the invention, being a stabilising device where neither shape
memory alloy wire is stressed; and
[0045] FIG. 6 is a view corresponding to that in FIG. 5 after
stressing of one of the wires.
DETAILED DESCRIPTION OF THE DRAWINGS
[0046] With reference to FIGS. 1 to 4, fastener 60 includes stud 54
having a locking cavity being circumferential groove 56. Fastener
60 includes aperture 58 (FIG. 2) into which stud 54 can be received
by a push-fit
[0047] Fastener 60 includes eight teeth 62, (three of which are
labelled in FIG. 1) each having a tongue 64 (FIG. 2) which can
engage groove 56.
[0048] Shuttle 66 is mounted for rotation within body 68 between
two positions. The first position is that shown in FIGS. 1 and 2,
where locking protrusions 70 maintain teeth 62 in the locking
position into groove 56 of stud 54, when stud 54 is in aperture 58.
The second position is that shown in FIGS. 3 and 4, in which
shuttle 66 has rotated sufficiently so that teeth 62 are located in
apertures 72 between locking protrusions 70. In this configuration,
teeth 62 are no longer maintained in the locked position in groove
56 in stud 58.
[0049] Shuttle 66 is rotated from one position to the other through
shape memory alloy wire running through guides 73 and 75 (FIG. 1),
one being used to rotate shuttle 66 to the locking position and the
other to rotate it to the unlocking position. The shape memory
alloy wires are attached via crimp holder 93 as shown in FIGS. 2
and 4. Printed circuit board 102 supplies power and instructions to
fastener 60 and handles reports.
[0050] Fastener 60 includes rear cap 78. Power is supplied via
electrical wires 80.
[0051] Also shown in FIGS. 2 and 4 is stud optical sensor 83. This
senses whether stud 54 is in the locked or unlocked position and
can report to an external source (not shown).
[0052] Fastener 60 also includes overstress spring 100 (refer FIGS.
1 and 3).
[0053] As best shown in FIGS. 2 and 4, fastener 60 includes in this
embodiment sliding plug 87 mounted on detector pin 89. Compression
spring 91 serves to urge sliding plug 87 to the position in which
it closes off aperture 58, and also to cause ejection of stud 54
when unlocked. In the locked position (FIG. 2), optical sensor 83
detects detector pin 89. This enables fastener 60 to report that
stud 54 is engaged. When stud 54 is released and ejected, as shown
in FIG. 4, optional sensor 83 no longer detects pin 89 and fastener
60 can report that it is unlocked.
[0054] Reference is now made to FIGS. 5 and 6, in which stabilising
device 120 is illustrated.
[0055] Each of first shape memory alloy wire 104 and second shape
memory wire 106 is attached to rocker plate 108 by suitable means
(not shown). Rocker plate 108 can pivot about pin 114 and has a
groove along each edge 110 and 112 to act as a guide for wire 104
and wire 106 respectively.
[0056] If wire 104 contracts, rocker plate 108 will pivot about pin
114 to transfer a small amount of stress, in the form of elongation
to wire 106. The reverse will happen if it is wire 106 which
contracts (as shown in FIG. 6). In this way, when one shape memory
alloy wire is subjected to a stress greater than that to which the
other shape memory alloy wire is subject, the stress on the first
wire is reduced by stressing the other shape memory wire to a small
extent.
INDUSTRIAL APPLICABILITY
[0057] As will be readily appreciated by those skilled in the
various arts, the invention disclosed herein are not limited to the
examples set out and have wide applications in many areas,
representing significant advances in the relevant art. In
particular, the invention provides a fastener which is less subject
to contamination, and a stabilising device which can enhance the
operation and longevity of devices using shape memory alloy
wire.
* * * * *