Patent Application
20080216292
This invention relates to fasteners. The type of fastener with which the invention is concerned is particularly useful as a temporary fastener but the invention is not limited to that application.
Temporary fasteners are used in various fields, such as in the aerospace industry and particularly in the assembly, maintenance and repair of aircraft and in the custom auto industry. For ease of illustration, the description below will deal generally with the aerospace industry. However, it is to be understood that the invention is not limited to this area.
To a large degree, aircraft manufacture, maintenance and repair involves insertion of fasteners by hand. For example, in manufacture of aircraft the assembly of the panels to the frame is exceptionally labour intensive. Each rivet is normally hand-fastened. Much the same procedure is followed for maintenance and repair.
As part of the riveting procedure, it is necessary to hold a panel to the frame, or to hold different layers together, by using temporary fasteners. It is common practice to use a temporary fastener in every sixth or eighth rivet hole for this purpose. The use of power tools is limited, particularly in the case of maintenance and repair where there is a high danger of explosion through sparking. Consequently, the various types of temporary fasteners which have been designed for use in the aircraft industry require insertion and/or extraction by hand or by use of hand tools.
There are several types of temporary fasteners which have been designed for use in the aerospace industry. Perhaps the most popular is known as the Cleco fastener. These are spring-loaded and are installed by the use of special pliers, which compress the spring to extend an internal pin downwardly. In this configuration, the pin may be inserted in the rivet hole. Once the compressed spring is released, tension on the pin will draw the skin or panel to the frame or the layers of material together.
Another type of prior art fastener is the wedge fastener. This type of fastener has two or more flexible arms which can be inserted into the rivet hole. The arms end in expanded shoulders and the layers of material to be clamped are compressed between the shoulders and a spacer forced towards the panels to be secured.
There are many drawbacks experienced with prior art fasteners. They can be expensive and awkward to use. They can cause burring to the rivet hole, requiring deburring and swarf removal. They can be limited as to depth and pressure requirements, thus necessitating a range of different fasteners, depending on purpose. There can be problems in riveting composite materials, or with materials having curved surfaces. Installation and removal may require a certain amount of physical strength on the part of the operator. Removal of the fastener is often more difficult than installation, particularly if the layers of material are bonded as well as riveted. Prior art fasteners may jam in the rivet holes, requiring physical force to dislodge them. Jamming may be exacerbated when sealant or adhesive is used between the layers of material to be riveted. Fasteners need to be cleaned periodically to remove adhesive.
There are various drawbacks experienced with the use of special tools required to install temporary fasteners, such as Cleco. For example, the special pliers may be somewhat clumsy to use and can slow down the installation of the temporary fasteners, because the fastener must be fed into the tool each time before installation. Since hundreds of temporary fasteners need to be installed during a shift, the fingers of the user may experience pain or suffer damage. The special pliers may be difficult to operate if the user has small hands. A significant amount of physical strength may be required to compress the spring of the Cleco fastener using the special pliers. Attempts to use power versions of the special pliers have not been satisfactory, because of access problems and the variety of fasteners which needs to be handled. These requirements for physical strength may limit the type of worker who can be employed in the aerospace industry.
It is an object of this invention, at least in some embodiments, to provide a temporary fastener which does not necessarily require the fastener to be initially mounted in a special tool for installation. It is a further aim of the invention to provide a temporary fastener which is relatively simple to use and which obviates or alleviates some of the other disadvantages found with prior art fasteners, and, for example, which can accommodate different depth and pressure requirements. It is a further object of the present invention, at least in some embodiments, to provide a fastener which can be used to fasten the different types of materials which are becoming increasingly common in the aerospace industry, such as composite materials including carbon fibre and/or fibreglass as well as steel and aluminium. It is a further object of this invention, at least in some embodiments, to provide a temporary fastener which can be used with curved panels, such as those necessary for aircraft construction.
Where a releasable fastener is required for temporarily fastening work surfaces in a “blind” situation, such as the attachment of surface material to the wing of an aircraft, it may be a requirement that the fastener be removable in a single assembly and that no part of the fastener is sheared off so as to be left behind. Embodiments of the present invention may be useful in a “blind” situation.
Accordingly, in a first aspect, the present invention provides a fastener including:
The fastener of the invention is preferably intended for use as a temporary fastener. However, the fastener of the invention may also be employed as a permanent fastener. Such a fastener can be used as a temporary fastener or tack, especially in the aerospace industry, the fastener being removed by drilling out where it is no longer required.
The fastener is preferably made fully or partly of material such as glass-filled nylon or similar material (but other materials may also be suitable). One or more different materials may be used in combination. For recycling purposes, it is preferred to use a single material, however.
The fastener of the invention may take any suitable shape. Non limiting examples are cross-sectional shapes which are circular, square or hexagonal. Similarly, elements of the fastener may have cross-sectional shapes which are circular, square or hexagonal, as examples.
The first work engaging member may take the form of a bearing or pressure foot, mounted on the longitudinal body and adapted to be urged towards work surfaces which are to be trapped between the first work engaging member and the second work engaging member, so as to create pressure on the work surfaces and compress them together. The first work engaging member may include a shear gallery to assist in shearing off the second work engaging member in those embodiments where this is desirable.
The first work engaging member, preferably in the form of the pressure foot, may present a flat profile or a profile of another shape to the work surface it is to contact. The foot may assume any desirable shape. In particular, the foot may be shaped so as to fit into a depression formed in the work surface so that, ultimately, the rivets or other permanent fasteners will be countersunk into the surface.
The second work engaging member is associated with the longitudinal body. Preferably, the second work engaging is mounted on or attached to or integral with the longitudinal body. Where the second work engaging member is separate from the longitudinal body, in one embodiment it is integral with, or joined to, the first work engaging member.
It is preferred that a guide or locater probe is included at one end of the longitudinal body, to assist in guiding the fastener into an aperture such as a rivet hole. The other end of the longitudinal body may include a guide for a tool for insertion of the fastener.
The second work engaging member includes means capable of assuming two positions. In the first position, where the means is of narrow cross-sectional area, the second work engaging member can be inserted through an aperture such as a rivet hole. In the second position, the cross-sectional area of the means should be wide enough to prevent the means being withdrawn from the aperture. In this way, it is possible to trap the work surfaces between the first and second work engaging members and to fasten them together.
Various embodiments of the means capable of assuming the first and second positions may be apparent to one skilled in the art. In a preferred embodiment, the means may be expandable and collapsible or can otherwise change shape so that the fastener can be withdrawn from engagement with the work surfaces. Embodiments of this are described below in connection with the drawings, and include wings and leaves.
The means on the longitudinal body for adjusting position of the first work engaging member on the longitudinal body may take any appropriate form. In one form, the means is a type of ratchet teeth/pawl combination. In this embodiment, the longitudinal body preferably carries ratchet teeth for over half its length. The pawl element is preferably mounted on the longitudinal body in engagement with the ratchet teeth. The pawl element may be adapted to engage the ratchet teeth so that the pawl element can move in one direction only, namely towards the first and second work engaging members. However, an alternate arrangement is one where the pawl element can be released from engagement with the ratchet teeth, so that the movement of the pawl element towards the first and second work engaging members can be reversed and the pawl element may be moved in the opposite direction.
The pawl element may be formed integrally with the first work engaging member. The pawl element is preferably mounted on the longitudinal body in engagement with the ratchet teeth. It is preferred that the pawl element is adapted to engage the ratchet teeth so that the pawl element can move in one direction only, namely towards the first and second work engaging members.
The position adjusting means may take other forms. One non-limiting example is the type of arrangement used for caulking guns, whether manually operated or operated by air or water, for instance. Another example is a screw-based arrangement, which can advance the first working engaging member in small increments. Still another example is an arrangement which provides unidirectional movement of the first work engaging member towards the work to be fastened, reverse movement being prevented or impeded by, for instance, means similar to scales used in a larger version on cross-country skis. Such an arrangement may be adapted to a molecular level via nanotechnology. Other examples will be apparent to one skilled in the art. Some of those other arrangements may permit infinite adjustability, rather than discrete adjustability which is found with the use of the ratchet teeth and pawl combination.
In one embodiment, the first work engaging member, the second work engaging member and the pawl element are made in one piece or in a fixed spatial relationship so that, essentially, the fastener comprises two parts, the first part being the longitudinal body having the ratchet teeth and, optionally, a locater probe and the second part being the combination of the first work engaging member, the second work engaging member and the pawl.
In another embodiment, the fastener of the invention is essentially in three parts, namely a first part being a longitudinal body including the ratchet teeth and including, by integration or by connection, the second work engaging member, a second part being the first work engaging member combined with the pawl element and a third part located internally of the longitudinal body and optionally including the locater probe.
The fastener in the two part embodiment can be suitable for situations where the work surfaces are not widely spaced apart and only a relatively small movement is required to draw them together. The fastener in the three part embodiment can allow more movement and depth capacity and can be suitable for drawing together work surfaces which are located more widely apart. The three part embodiment can permit a wider range of adjustment.
The fastener of the invention may be inserted in the aperture by hand. Preferably, the fastener is then tightened in position by (for example) advancing the pawl member along the ratchet teeth, by use of a suitable tool. A tool for tightening cross ties or cable ties may be adaptable for this purpose. Whereas in the case of prior art Cleco fasteners, the installer must first load the Cleco fastener in the tool, insert the fastener in the aperture and then release the spring in the fastener, in the case of the fastener of the present invention, the procedure can be carried out more efficiently. For example, a first operator may simply push the fastener into the aperture and a second operator can follow closely behind tightening the fasteners.
The fasteners of the first aspect of the invention can carry out functions in addition to that of fastening. For example, the fastener may include means for attaching one or more elements, such as cables. By way of another example, the fastener may be integrated with an element which needs to be mounted or annexed in a permanent or semi-permanent way to the work surface. Preferably, the attachment or integration takes place in conjunction with the first work engaging member, one embodiment of which is a pressure foot. It will be apparent to one skilled in the art that the attachment or integration can take place via other means on the fastener and that these are within the scope of the invention.
In more detail, one non-limiting example of such a secondary function of the fastener of the invention is the integration of a cable tie with the first working engaging member. The cable tie may be otherwise a conventional cable tie which encircles a cable or a plurality of cables and which can be drawn up around them by the use of ratchet teeth and a pawl in the normal manner. Similarly, hooks or loops can be attached to, or form part of, the fastener for mounting artwork or signage on walls or for mounting furniture, such as kitchen cupboards. It will be appreciated by one skilled in the art that there is a myriad of other uses.
It is preferred that the fastener of the invention is provided mounted in a continuous feeder strip. In the case where the fasteners are to be mounted by hand, this method of presentation can streamline the selection of fasteners and their manipulation. However, the continuous feeder strip may also be suitable for feeding automatically into a hand tool or robot.
The fasteners may be inserted into a continuous feeder strip. Alternately, the fasteners may be manufactured integrally with a continuous strip. The latter may be particularly suitable where the fasteners are formed by injection moulding: the fasteners may be connected together by a web to form a long strip of fasteners. Fasteners inserted into or manufactured in a continuous strip may be supplied as a cartridge, or in strips of appropriate length, for example, containing 20, 30 or 40 fasteners.
Where a machine tool or robot is used for the fasteners of this invention, the machine tool or robot may be driven in any suitable manner, but preferably pneumatically.
The present invention, in connection with the first aspect, also includes a method of fastening work surfaces using the fastener of the invention, the method including the steps of:
In further association with the first aspect of the invention, the present invention provides a method of removing the fastener of the invention from work surfaces fastened by the fastener, the method including the steps of:
In order to cause the second work engaging member to assume the first position, in some embodiments it may be necessary to disengage the position adjusting means, such as the pawl element from the ratchet teeth, for example, in the two-part embodiment referred to above. This may involve breaking off part of the pawl element. In other cases, it may not be necessary to disturb the engagement of the pawl element with the ratchet teeth. Further details of these arrangements are illustrated in the accompanying drawings and described below.
In a second aspect, the present invention provides a fastener including:
In an especially preferred embodiment relevant to temporary fasteners or tack fasteners, the fastener of the second aspect of the present invention includes means capable of assuming a first position of narrow cross-sectional area and a second position of wide cross-sectional area. This means is preferably part of or attached to the second longitudinal body.
It is further preferred that the first and second engaging means permit unidirectional movement of the first longitudinal body within the second longitudinal body so that, once the first longitudinal body is inserted in the opening in the second longitudinal body, the first longitudinal body can be pulled in one direction within the second longitudinal body but can not be pushed in the opposite direction.
The first longitudinal body is preferably a rivet made of a relatively hard plastic. The first longitudinal body may be suitable for manufacture by injection moulding.
The first longitudinal body may include the first engaging means for some or all of its length. One end of the first longitudinal body is preferably designed to engage an insertion tool, while the other end preferably takes the form of a probe to assist in insertion into apertures in work pieces.
Each of the first and second engaging means may be chosen from a range of configurations, such as helical thread, grooves and projections, serrations, sharp-edged annular projections, burrs and other suitable gripping members. When the fastener of the invention is designed to permit unidirectional movement of the first longitudinal body within the second longitudinal body, the first and second engaging means should operate so that there is ratchet effect between the first and second engaging means. The most preferred arrangement is one where the first engaging means is a helical thread or serrations, grooves/projections, etc, each having a shoulder adapted to engage a barb or shoulder in the second engaging means, to prevent bidirectional movement of the first longitudinal body.
The second longitudinal body is preferably generally cylindrical, with the second engaging means located in one part of the cylinder. The means capable of assuming a first position of narrow cross-sectional area and a second position of wide cross-sectional area, when present, preferably comprises a continuation of the cylinder, the cylinder being segmented in this area. These means are preferably wings hinged to the remainder of the cylinder.
In one preferred embodiment, the second engaging means takes the form of threads or annular grooves and projections, adapted to deform and increase in cross-sectional area through longitudinal slits cut into the threads or grooves and projections. In a second preferred embodiment, the second engaging means is shaped in an appropriate manner, to allow the first longitudinal body to slide axially through the opening. The second engaging means, in this embodiment, takes the form of internal threads or projections in at least part of the opening, and have an annular shape in cross-section, except that the annulus is shaped so that the inner periphery of the annulus is changed to the periphery of a hexagon. Other configurations may also be appropriate.
It will be appreciated by one skilled in the art, having read the above disclosure, that the relationship between the first and second engaging means will be such that the second engaging means permits axial movement, possibly unidirectionally, of the first longitudinal body within the opening, but can effect positive engagement of the first engaging means and the second engaging means when one longitudinal body is rotated relatively to the other.
While the above preferred embodiments refer to deformation of the second engaging means, it is to be appreciated that the fastener of the present invention may be constructed so that the first engaging means deforms, or so that there is some deformation of each of the first and second engaging means.
Especially where it is the second engaging means which deforms, it is preferred that the second longitudinal body is made from a relatively stiff plastic, such as glass-filled Nylon (trade mark). Suitable material is marketed by Du Pont, under the trade mark ZYTEL.
The second aspect of the invention in its broadest form represents an extremely efficient, quick coupling fastener. When it is used as a temporary fastener or tacking rivet, it can permit rapid attachment of work pieces with the ability to pull work surfaces together with a fine degree of adjustment.
The third aspect of this invention is concerned with variations of the “Fixing and Release Systems” invention, first disclosed in international patent application No. PCT/AU99/00185 (WO99/47819). The contents of that specification are incorporated herein by reference.
In a broad form, the Fixing and Release Systems invention as applicable to the third aspect of the present invention disclosed:
In a preferred embodiment of WO99/47819, the locking means is moveable in a deformable channel and in the first position the locking means prevents deformation of the channel in the region of the locking means.
In the variations in the third aspect of this present invention, the fastener is particular useful as a strip fastener. In this variation, the locking element is one, but preferably more than one, rotatable element adapted to be rotatable within the deformable channel, the axis of rotation being transverse to the longitudinal axis of the channel. The rotatable locking element is designed to present a wide dimension towards the mouth of the channel when the fastener is in the locked position and a narrow dimension towards the mouth of the channel when in the unlocked position. The mouth of the channel is prevented from deforming inwardly when the locking element locks it via the wide dimension. The mouth of the channel can deflect inwardly when the locking element presents the narrow dimension towards the mouth of the channel.
Preferably, the locking element is moveable by a magnet or electromagnet from the locked to the unlocked position. Even more preferably, there is a plurality of locking elements side by side with each other and each uses magnetic means to maintain alignment with its neighbour. The purpose of this is to enable each “set” of rotatable locking element to rotate in unison, so that all present their narrow edges to the mouth of the channel at the same time or, conversely, all present their wide edges to the mouth of the channel at the same time.
In a simple version of this type of fastener, a magnet can be “swiped” along a line of locking elements to cause them to rotate through 180°, to either lock or unlock. Reversing polarity of the magnet and swiping it again will cause the locking elements to rotate through 180° to regain their original position.
The rotatable elements may take any desired shape, provided they perform the desired function of preventing inward deflection of the relevant part of the walls (eg, the mouth) of the channel when in the locked position. As one example, the rotatable locking element may resemble a wedge in side elevation and a circle or square in plan view. As another example, the locking element may itself be two or more rotatable elements with the shape of each in side elevation being constant, eg, a rectangle. In this latter example, the rotatable elements cause a bar or similar means to be raised or lowered. When the rotatable elements are caused to rotate in one direction, the bar is elevated to prevent deflection of the relevant part of the channel walls. When the rotatable elements are rotated further or in the reverse direction, the bar is caused to descend.
Other embodiments of the locking means are possible and will be apparent to one skilled in the art.
The invention in its various aspects will now be described in connection with certain non-limiting examples thereof described in the accompanying drawings:
Referring first to
Fastener 80 has longitudinal body 82 which carries several ratchet teeth 22. At the end of fastener 80, intended for insertion in apertures 12 and 16, is a probe 84 to help with alignment.
Fastener 80 has, moulded in one piece, first work engaging member 86 (in the form of a pressure foot), pawl element 88 and second work engaging member 90. Pawl element 88 engages ratchet teeth 22 through ratchet lock 92.
In this embodiment, second work engaging member 90 is made of four leaves 94. In
Probe 84, which is located at one end of longitudinal body 82, tapers out to expanded part 100. When longitudinal body 82 is moved upwardly (with reference to the orientation shown in
In
Whereas the embodiment in
With reference to
Work pieces 14 and 18 are caused to move together to the position shown in
The part of longitudinal body 82 beyond pawl element 88 can now be sheared off by a suitable cutting means (partially shown at 108), as shown in
If it is desired to remove fastener 80, the procedure shown in
The second embodiment in
In the
In the
Turning to the sequence of insertion shown in
Next, as shown in
Continued tension on fastener 120 in the direction of arrow 142, combined with advancement of pawl element 88 down ratchet teeth 22, draws work pieces 14 and 18 together as shown in
To remove fastener 120, refer to the procedure shown in
Turning now to
As is the case with conventional cable ties, arm 148 carries teeth 152 and arm 150 includes complementary teeth 154 in passage 156.
Once fastener 120 has been inserted in the manner illustrated in
It will be appreciated that, instead of the cable tie, another type of fastening element could be used, such as a loop (for hanging pictures for example) or a cup hook. Alternately, fastener 120 could be integrated with any other type of product which it was desired to annex or affix to a work piece.
Reference is now made to
It will be appreciated that the embodiments in these drawings are illustrative of embodiments of a temporary fastener or tacking rivet. However, these drawings also serve to illustrate how the invention would work in other situations, if the means capable of assuming the first and second cross-sectional area, positions is omitted.
Referring first to
Second longitudinal body 206 has general cylindrical opening 208. Opening 208 continues through throat 210. Throat 210 has second engaging means, in this embodiment being internal helical threads 212. In the region of throat 210, second longitudinal body 206 has slits 214. Only one slit 214 is shown in
Second longitudinal body 206 includes wings 216. These are attached to longitudinal body 206 at hinges 218 and are preferably provided as four wings, two of which are shown in
First longitudinal body 202 includes probe 220 and stepped section 222, designed to fit into an insertion tool (not shown).
First engaging means 204 and second engaging means 212 each includes shoulders 224 and 226 respectively (refer
To operate fastener 200, first longitudinal body 202 is inserted into second longitudinal body 206, by feeding stepped portion 222 through opening 208 from end 228. The assembled fastener is then inserted into an insertion tool (not shown) which grips some or all of stepped portion 222. Assembled fastener 200 is inserted by the tool into countersunk hole 230 in two or more work pieces, schematically shown at 232. The insertion tool is activated so that it pulls up first longitudinal body 202 to a preset tension, shoulders 224 ratcheting along shoulders 226. Movement of probe 220 upwardly with reference to
The protruding part of first longitudinal body 202 is trimmed off (by the insertion tool) flush with the head of counter sunk hole 230. The remaining part of first longitudinal body 202 maintains work pieces 232 together with the desired tension.
If fastener 200 is to be replaced by a permanent rivet, fastener 200 is drilled out and replaced in known manner.
Turning now to
Threads 234 can flex sufficiently to permit external threads 204 on first longitudinal body 202 to pass through when first longitudinal body 202 is being drawn upwardly in
The embodiment in
It is possible that the embodiment of the fastener illustrated in
Turning now to the embodiment of the third aspect of the invention in
Fastener 160 has three rotatable locking elements 158 mounted in channel 162. Each locking element 158 can rotate about axis 164. Each locking element 158 is generally wedged-shaped in side elevation, having a thick edge 166 opposite a thin edge 168 (refer
As best seen in
In order to release the engagement by protrusion 176 with the element (not shown), it is necessary to rotate locking elements 158 so that the thin edges 168 are situated at the upper part 172 of channel 162. To achieve this, a simple bar magnet may be swiped along base 178 or in its region. Depending on polarity of the magnet, locking elements 158 will rotate through 1800 either to the right or to the left. A magnet 170 on each locking element 158 ensures that all locking elements rotate in unison. When thin edges 168 lie between upper parts 172, there is room for deflection and protrusion 176 may no longer engage the element (not shown).
Reversing the polarity of the bar magnet and swiping it again will cause the locking elements 158 to turn to their original position.
As will be appreciated by one skilled in the art, rotation of locking elements 158 may be achieved by other means, for example by use of a electromagnetic field. In another embodiment (not shown), locking elements 158 may have consistent thickness throughout, rather than being wedge type and shaped as shown in
As explained in further detail in patent application No. WO99/47819, the locking and unlocking may be effected by remote activation, with no material connection made between the actuating means, such as the magnet, and the locking elements. It is within the scope of the present invention, however, that hard wiring, or other material connection, may also be used in the case of the third aspect of the invention.
It is anticipated that the fasteners of the present invention can be manufactured at a very low price and that, because the first work engaging member (in the fastener of the first aspect) can be made of plastic or other mouldable material, it will be economical to provide the fastener with variations in that member—for example, to accommodate use with curved surfaces.
Further, it is easy to adapt the fasteners of the present invention to composite work pieces and to minimise damage during temporary assembly.
In relation to industries where it is desirable to use temporary fasteners until permanent fasteners are inserted, and especially where robots insert the permanent fasteners, the versions of the fastener of the invention where part of longitudinal body can be sheared off are particularly useful. The sheared off fastener presents a low-profile appearance which does not impede robotic operation.
The connecting means of the invention is useful as a simple lock which can be hidden from view and which can be operated by a bar magnet or other activator. One application is as a lock for a medicine cabinet, for example.
It will be further appreciated by one skilled in the art that the scope of the present invention is not limited to the particular embodiments described and that modifications and variations are within the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004900529 | Feb 2004 | AU | national |
| 2004902475 | May 2004 | AU | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/AU05/00137 | 2/4/2005 | WO | 00 | 8/2/2006 |
