EP2447932A1

EP2447932A1 - Fastener

Info

Publication number: EP2447932A1
Application number: EP10251894A
Authority: EP
Inventors: designation of the inventor has not yet been filed The
Original assignee: British Telecommunications PLC
Current assignee: British Telecommunications PLC
Priority date: 2010-11-02
Filing date: 2010-11-02
Publication date: 2012-05-02

Abstract

A fastener for use with an elongate member having a longitudinal axis, the fastener comprising
a housing, and
an arm for looping about the member, the arm being attached to the housing,
wherein the looped arm is configured to urge against the member along a plane oblique to the longitudinal axis of the member during use.

Description

This invention relates to a fastener to enable attachment of identity tags and other items, in the wider context of managing, identifying and tracking physical assets such as equipment and plant.
An implementation of the invention is discussed against the background of a telecommunications network although it would be appreciated that it can be deployed in any type of network or system. Indeed, the invention can be usefully deployed for a single item of equipment, plant or other physical item outside of a network or system.
In a telecommunications network, the sheer diversity of equipment and plant involved, in new as well as in legacy networks, presents a particular challenge for their identification by labelling or tagging. There are a number of known plant-tagging solutions, such as colour-coding, pattern-coding, serial numbers and bar-coding, and radio-frequency identification (RFID); the records components for each such tagging solution are also known in the art. These can be built into the item in question, or else the item can be retro-fitted to carry the necessary identification information.
For example, the use of RFID tags to identify cables is ideal in a crowded setting such as in an exchange or in a cable joint, so that there is less need for an engineer to detect and identify this by reading the serial number on a tiny handwritten label. However, retrofitting RFID tags on certain types of equipment and plant present problems. The curved, cylindrical, surface of elongate cables is not an ideal base or support for an RFID tag: this is particularly so in the case of cable of small diameter. This is due to the fragility of the RFID component itself, the difficulty in reading the data contained therein, or physical interference or hazard from a projecting RFID component fastener or attachment. The antenna and the application-specific integrated circuit of passive RFID tags positioned on curved reading planes such as the surface of a cable or pipe presents a reduced effective read/write area to the scanner or reader, compared to a tag positioned on the flat surface which present a larger effect surface area.
Known solutions include "cable tags" from Synometrix Integrated Technologies of Taiwan, taking the form of a "secure RFID zap strap or tie-on RFID tag", which essentially comprise an RFID tag placed on a flap having a flat surface, which is in turn attached onto a conventional cable tie (http://www.synometrix.com/RFID cable tag specification.shtml, referred to 25 October 2010). As is well known, a cable tie comprises a gear rack arrangement which prevents loosening once engaged; the loop formed by the cable tie tape can only be pulled tighter.
Such cable tags may be used to identify cables, but are not ideal, as the RFID component flap projects disruptively from the cable resulting in snagging, and the cable tie tape itself could slide along the cable and be "lost" if it is not sufficiently tightly fixed. It is also susceptible to tampering. Its propensity to be over-tightened (e.g. to discourage sliding) results in a high likelihood of imparting a crushing force on the surface of the cable in a radial direction. This makes such cable tags problematic when used optical fibre cables of small diameter which comprise an arrangement of optical fibres or fibre units around a central strength member. An over-tightened cable tie may adversely affect the performance or even physically injure such cables where the optical fibres are positioned immediately under the external sheathing due to the crushing force imparted at the point of contact.
It is therefore desirable to attach records components such as an RFID tag onto an object or physical item in a way which addresses the above issues.
In a first aspect of the invention, there is provided a fastener for use with an elongate member having a longitudinal axis, the fastener comprising
a housing, and
an arm for looping about the member, the arm being attached to the housing,
wherein the looped arm is configured to urge against the member along a plane oblique to the longitudinal axis of the member during use.
The fastener may be considered to refer to the arm of the device, as well as more generally to the entire device. In the main, the arms are configured to enable them to resiliently bear upon the cable in a way so that the loops around the cable describe a plane which is slanted or oblique to the longitudinal axis of the cable. This removes or reduces the compressive force placed axially upon the cable by use of a cable tie fastener, by distributing the frictional force required to attach the fastener to the cable surface over a bigger area by obliquely urging the arms against the cable.
In various embodiments, the arms may comprise pre-formed loops into which the cable can be inserted, or else the arms may be open (i.e. attached to the housing or fastener at only one end) so that the user forms the loop around the cable during use. The force urging the fastener arms is preferably obtained by a biasing force from means which are provided within the structure of the fastener, or else formed when the user loops and secures the loops about the cable or such member. This force can stem from the structure and/or materials from which the arms (or parts thereof) are made, or else may be provided by means external to the arms in the form of e.g. springs.
In a tamper-proof embodiment, the arms are configured to be secured using a closure arrangement which is cannot be opened again after closing, without such an attempt being detectable e.g. by breaking.
In a second aspect of the invention, there is provided a method of fastening a records component to an elongate member having a longitudinal axis, comprising

looping an arm of the fastener about the member, and
causing the arm to urge against the member along a plane oblique to the longitudinal axis of the member during use.

The invention will now be described, by way of example only, with reference to the following drawings in which:

Figure 1 shows a view of an embodiment of a fastener of the invention,
Figure 2 shows a view of another embodiment of the fastener in an open position,
Figure 3 shows the fastener of Figure 2 being attached to a cable,
Figure 4 shows another view of the fastener of Figure 2,
Figures 5A and 5B are schematic views of embodiments of the fastener,
Figure 6 shows a further embodiment of the fastener, and
Figure 7 is a schematic view of yet another embodiment of the fastener.

Figure 1 is an overall depiction of a fastener (2) of the invention, shown attached to a cable (100) which in this description is an example of a physical item or object which is to be tagged using an RFID chip or other records component such as a bar code sticker.
The fastener (2) consists of a housing (4) which during use carries the records component. This is attached to the cable or other object by means of an a strap or an arm (6) which encircles the cable in a single loop. The fastener shown in this drawing has two arms (6a, 6b), each extending from the opposite ends of the housing. In this "closed" position, the fastener arms, which are manufactured so that only one end is attached to the housing, are secured in place by means of closure arrangements, which are present also in the embodiment shown in Figure 2, and which will be discussed in that connection as follows.
Figure 2 depicts another version of the fastener (2) in an "open", "unattached", position, prior to attachment to the cable. Whereas Figure 1 depicted the "upper" surface of the housing (4), the view in Figure 2 is of the "underside" of the housing, and a space or cavity for accommodating a records component such as an RFID chip (8) can be seen. The arms (6a, 6b) are here shown to be un-looped, or in an open position. They are each attached to the housing at one end (12) and terminate in a claw-like arrangement (18) at the other end comprising a number of projections or prongs (10). A similar arrangement (16) comprising prongs (20) is provided on each side of the housing as shown. An arm closure arrangement is made up of a set of prongs on the arm end and a set of prongs on the housing end (18, 16). The prongs are configured to engage with each other in use so that when the prongs are brought together, they can catch onto each other and interlock into place. In a temper-proof embodiment of the closure arrangement, the prongs take a form which cannot be parted after interlocking without detection of the closure, for example, prising the closure arrangement open will break it.
When the closure prongs are engaged, the arms of the fastener are formed into a loop around the cable. There are two arms and two closure arrangements in the embodiment shown in Figure 1, so that essentially two loops (6a and 6b) are formed by winding the arms around the cable a number of times, one with each arm, which extend away from the housing which bears directly onto the cable as shown. This allows for the housing (4) to be securely fastened to the cable. This closure mechanism is identical or similar to the one deployed in the fastener shown in Figure 1 above.
The arms are manufactured from a generally pliable material which allows them to be bent around the cable such as diameters ranging from 6.5 to16 mm. Alternatively the arms can be formed to be rigid with flexible sections at predetermined points along their length, e.g. where the external dimension of the item being fastened is known. In the embodiment shown in Figure 2, the arms are generally pliable, but one or more sections (14) are provided to be pre-bent, or else to be more bendable from being formed from a different material from the rest of the arm, or being of a reduced thickness relative to the rest of the arm. In preferred embodiments, barbs or bristles (17) are provided along the arm. In the fastener shown in Figure 2, such bristles are provided along certain sections of the arm only. As will be explained further below, these help to reduce the pressure placed on the cable by the loop.
Figure 3 depicts the fastener (2) partly-attached to the cable (100). One arm (6a) is shown un-looped, while the other (6b) encircles the cable in a crossed, double-loop formation which form resembles a figure-eight or an infinity sign. This manner of encircling the cable essentially forms two loops around the cable along one arm. In this description, these two loops shall be referred to as the "loop sections" collectively and respectively, the "near loop section" and the "remote loop section" (relative to their positions to the housing). This configuration may be contrasted with the single loop of the arms about the elongate member shown in Figure 1.
The loop is held in position against the cable through the closure of the clasp by the interlocking of the claw arrangements (18, 16, not seen in this Figure 3), which secures the looped arm. When fastened onto the cable, the RFID records component (8) is encased within the housing (4) facing the cable and so is protected from physical harm in a preferred arrangement.
The loop thus formed by an arm is urged against the cable along a plane which is slanting or oblique to the longitudinal axis of the cable, in a way which will be elaborated below in connection with Figures 5A and 5B. This enables a firm grip to be formed on the cable surface without imparting any excessive crushing force. In turn, the housing containing any records component is firmly urged against the cable or other item it is to be fastened to. Slanting the loop in this manner distributes the frictional forces between the surface of the arm and the surface of the cable over a wider area. This may be contrasted with a conventional cable tie, in which the strap is tightened around the cable in a in a single wind (i.e. not in a helical fashion) parallel to the radial axis of the cable along its circumference. Failure to secure sufficient grip with such a cable tie will allow the fastener to undesirably slide along the cable, while over-tightening could adversely affect the performance and structural integrity of a fragile cable and the optical fibre unit within it as mentioned above.
Use of an obliquely-disposed loop has the further advantage of being able to accommodate some variation in the external dimensions of the cable or other item the fastener is to be attached to, by changing the angle of slant taken by the loop. So for example, the fastener can also be used with a cable with a smaller outer diameter, by extending the loops away from the housing further. If the cable is too large to encircle twice in a double loop, the arm can be looped a single time around the larger diameter, with the slant adjusted accordingly to take up any excess in the arm length, further including the provision of a resilient or biasing at the section at which the arm is attached to the housing or similar part of the fastener.
The loop configuration also allows for the fastener to be selectively moved along the length of the cable, e.g. by pinching the arms to move the loops temporarily away from the cable surface, which can then be made to re-grip the cable surface by releasing the pinch allowing the arms to re-engage with the cable surface.
The urging effect of the arm loop against the cable surface is derived from the particular double-looped configuration adopted in the embodiment shown in the drawings: specifically the crossing of the arms as well as the manner in which the arms are attached to the housing, as will be explained in greater detail below in connection with Figures 5A and 5B. The resilient material and configuration of the arm along its length also contributes to the effect when it is wound and secured into position. It is not essential to the invention that the arm be coiled about the cable in the specific manner shown however, as long as it is brought to bear resiliently against a part of the cable along a plane which is oblique to the longitudinal axis of the cable. Other coiling or looping methods within the scope of the invention are discussed below.
In the embodiment shown in the figures, a looped arm does not bear against the surface of the cable continuously along the loop length, as one arm section passing over and above another arm section in the vicinity of where they cross each other, as can be seen in the view of the fastener in Figure 4. The arm may also be inherently resilient or "springy" along its length so that it does not conform completely to the cable surface. Such intermittent or point contact between the surfaces has the advantage of reducing the risk of excessively compressing upon the cable even further, again in contrast with the continuous contact of a cable tie. The manner in which the arms are urged against the cable due to the way they are looped and secured, also discourages continuous contact. In the embodiment under discussion, sections of the looped arms bear upon the cable in the direction in which they are pushed, as described further below. The presence of bristles (17) reduces the contact even further: these are positioned to engage with the cable surface as well as with the arm at the crossover point, which helps keep the loop in place to improve the overall grip of the fastener on the cable.
It should be noted that while the use of intermittent or point contact in the above arrangement advantageously reduces the crushing or radial compression of the cable, that nonetheless this is not essential to the primary aspect of holding the fastener to the cable or other item. In particular, it is possible to realise the advantages of the invention even if the looped arms were to have continuous contact with the cable surface, as much of the compressive force required by a cable tag arrangement is mitigated by causing the arms to bear against the cable surface at an oblique angle.
It can also be appreciated that the arms need not be double-looped with a crossover section as shown in the drawings. For example, they may comprise a simple (i.e. not crossed), single loop (60a, 60c in Figure 7), wherein the arms are resiliently attached to the housing (4) through specific dimensioning and choice of materials for that purpose. Other resilient attachment methods are possible, e.g. use of a leaf spring which would cause the closed looped arms to bear upon the cable as required, or in the arrangement discussed below in connection with the embodiment shown in Figure 6.
Figure 5A depicts a schematic side view of fastener (2) of the invention, and illustrates the oblique or slanted plane taken by the looped arms (60a depicting a single loop, and 60b depicting the crossed loop) in use while urging against the cable. Figure 5B is a top plan view of the fastener (2) of Figure 5A attached to the cable (100) depicting only the arm which forms the double, crossed loop. The dotted lines between the two drawings refer to the sections of the arm (60b) which correspond in each view.
In the embodiment of e.g. Figure 1, the urging effect of the arms against the cable is obtained from the resilience of the sections to which the arms are joined to the body, in particular the sections of the arms which cross over each other, which acts like a springloaded fulcrum at which location the arms bend. As noted earlier, essentially two loops are formed around the cable, taking the form of a figure-eight or infinity sign. This form is maintained even in the absence of the cable, i.e. the arms when looped in this manner rests in its unused position also in a figure-eight when lying along a single plane. Tying the arm around the cable in such a configuration is conceptually identical to bending the planar figure-eight looped arm at the loop cross-over point from its resting position, to allow insertion of the cable through the two loop sections. When released from being bent, the loop seeks to resume its original resting position, causing the two loop sections to resiliently bear upon or urge against the cable in a plane which is oblique to the longitudinal axis of the cable in the directions depicted by the arrows "Y" and "Z", i.e. towards and outwardly from the crossed section of the arms. Figure 5B shows the remote arm loop of the arm (60b) which bears upon the cable in the direction "Z" to hold the fastener to the cable; the near arm loop would have the effect of causing the cable and the housing to bear upon the cable in direction "Y".
It will be appreciated that looping the arms so that they cross can form a resilient fulcrum or a bending point or section. One or more such crosses may be formed by various looping methods, wherein it may be expected that the more crosses and loop sections formed, the greater the grip of the fastener on the cable surface. Such improved grip is obtained however without the attendant compressive force that would result from a throttling over-tightening of a conventional cable tie fastener.
An alternative embodiment of the fastener of the invention is depicted in Figure 6, in a resting, unused, position. Like the fastener shown in Figure 1, it employs a single loop around the cable. However, it differs in that instead of having open arm lengths, the arm (60a) are closed so that both ends are attached to the housing (4) to form receiving loops. During use, in a manner similar to the above crossed loop embodiment, the arms are bent at the fulcrum sections where they join to the body, allowing for an elongate structure like a cable (not shown) to be inserted into the receiving loops. When released from being bent, the arms seek to resume their original resting positions, with the effect that the simple, uncrossed loops urge against the cable in a plane which is oblique to the longitudinal axis of the cable.
This is schematically depicted in Figure 5A, in which the looped arm (60a) urges against the cable in direction "X". It may be observed that the direction in which the loops are urged in both embodiments, are towards the bending section or fulcrum which resiliently biases the arms to their resting position in which they lie substantially flat in a plane in line or parallel to the housing of the fastener.
The fastener of this embodiment can be made entirely of a material which allows for the sections joining the arms to the housing to bend as desired, or else the specific section only can be made of such a material.
As may be appreciated, this particular embodiment of the fastener is easier to fit, but can be used only where an end of the cable is available to slide the fastener along during installation, in contrast with the earlier-discussed version which can be fitted at any point along the elongate member. The skilled person would however appreciate that simple modifications may be made to the embodiment in Figure 6 to open up (and then close, if necessary, e.g. to secure the loop) one or both of the arms as necessary during installation. This could include tamper-proofing the fastener e.g. so that the RFID or other records component cannot be removed from its cavity (62) by providing that any opening/closure mechanism cannot be re-used, or that an attempt to re-use the fastener is detectable. Also, there is less spreading out or distribution of the frictional forces mentioned above, in the single, single loop, but this would suffice to fasten lightweight objects such as an RFID chip.
Figure 7 depicts an embodiment of the invention comprising a single looped arm (60c) holding the housing (4) to the cable (100). The skilled person would be able to conceive of other implementations and applications in which a variety of number and configuration of arms may be deployed for lesser or greater gripping effect, or on items which are not elongate or tubular in form.
While a cable in a telecommunications network context has been used for description of the invention, this is merely illustrative and does not restrict the application of the invention to a variety of industries and fields to carry different records components (such as a bar code) or other items. Indeed the fastener may be used to simply attach the housing (without any other further object) to another item.
The skilled person would also appreciate that a number of variations in the construction and application of the fastener are possible. For example, the fulcrum sections of the fastener which resiliently bend and urge against the cable or such other item, need not be made from a deformable material, but instead comprise parts joined by a spring. The loops need not be completely closed. They could alternatively be configured to coil around the cable in a helical fashion, with one or more biasing means (e.g. leaf springs) provided along the length of the arm, i.e. at intermediate points as well as at the junction between the arm and the housing as arranged in the embodiment shown in Figure 6. The methods and configurations as described above and in the drawings are therefore for ease of description only and not meant to restrict the apparatus or methods to a particular arrangement or process in use. It will be apparent to the skilled person that various permutations on the methods and apparatus described are possible within the scope of this invention as disclosed.

Claims

A fastener for use with an elongate member having a longitudinal axis, the fastener comprising
a housing, and
an arm for looping about the member, the arm being attached to the housing,
wherein the looped arm is configured to urge against the member along a plane oblique to the longitudinal axis of the member during use.
A fastener according to claim 1 including biasing means to urge the looped arm against the member.
A fastener according to claim 2 wherein the biasing means is provided along the length of the arm.
A fastener according to claim 2 wherein the biasing means is formed by looping the arm about the member a number of times.
A fastener according to any one of claims 2 to 4 wherein a section of the arm is configured to serve as the biasing means.
A fastener according to any preceding claim wherein the arm includes bristles.
A fastener according to any preceding claim wherein the arm is attached at one end to the housing, the fastener including a closure for securing an unattached end of the arm while looped around the member.
A fastener according to claim 7 wherein the closure comprises a set of interlockable prongs.
A fastener according to claim 7 or claim wherein the closure is arranged to break upon being opened after having been closed.
A fastener according to any preceding claim wherein the housing is arranged to house a records component.
A method of fastening a records component to an elongate member having a longitudinal axis, comprising
- looping an arm of the fastener about the member, and

- causing the arm to urge against the member along a plane oblique to the longitudinal axis of the member during use.