GB2467125A

GB2467125A - Cable tie with separate locking member

Info

Publication number: GB2467125A
Application number: GB0900971A
Authority: GB
Inventors: Keith Ebbrell
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-01-21
Filing date: 2009-01-21
Publication date: 2010-07-28
Also published as: GB0900971D0

Abstract

A fastener 10 having a strap 12 that has a near end 14 and a tail end 16, and a locking member 20. The strap 12 includes gripping surface 19 formed on its upper surface which provides means for locking bundles of elongated items together. The locking member 20 is formed separately from the strap 12. The locking member 20 may have locking means in the form of a pawl 32. The strap 12 may have a gripping surface 19 that engages with the pawl's teeth 34. The gripping surface 19 may have protrusions which are triangular, square, semi circular, polygonal, or ridges and troughs.

Description

FASTENER

The present invention relates generally to fasteners and, more particularly, to ties which can be formed into a closed loop. Ties are well known in the art and are widely used in a variety of different applications. One tie which is well known and widely used in the art is the cable tie. Cable ties are commonly used in coimnerce to bundle together a plurality of objects, such as a group of wires or cables.

One type of cable of tie well known in the art comprises a serrated strap integrally formed with an apertured locking member. In use, the cable tie can be formed into a closed loop by inserting the free end of the serrated strap through the apertured locking member. With the serrated strap inserted through the apertured locking member, an internal pawl or locking tang disposed within the apertured locking member loelcably engages the senations of the strap to prevent the strap from being withdrawn out the apertured locking member. In this mariner, the engagement of the internal pawl onto the serrated strap secures the cable tie in its closed loop configuration.

The cable tie can then be tightened to firmly grip the cables or wires. With the plurality of wires grouped together, the strap of the cable tie is wrapped around the bundle of wires. The free end of the strap is inserted through the apertured locking member to form a closed loop around the bundle.

With the cable tie formed into a closed loop, the free end of the strap is advanced through the apertured locking member to sinch the cable tie strap tightly around the bundle. The cable tie prevents the strap from being pulled in a reverse direction to expand the loop size.

After a cable tie secures a bundle of articles a tail extends from the locking member of the cable tie. In common practice, the tails are cut off with wire cutters or left in situ. If cut-off this wasted excess length of strap is then discarded. In some cases the majority of the length strap of material as the cable tie strap does not need to be so long. This is an inefficient use of resources and wasteful. Clearly this has an adverse impact on the environment and the cost associated with needlessly manufacturing such a long cable tie is excessive.

Other limitations include the fact that if a large number of cables need to be secured together it is necessary to either connect two or more cable ties together or carry around varying lengths of cable tie to accommodate all potential uses and needs.

This clearly impacts on cash flow for a company and the need to carry potentially unnecessary stock.

Another example of such cable ties in use are Rapstrap (fl However this product is not suitable for all applications for which conventional cable ties are useful.

One problem with this particular tie is that it is not mechanically strong and therefore the use of the tie is limited in certain industries and for certain applications It is an object of the present invention to overcome or alleviate one or more of

the problems associated with the prior art.

In accordance with a first aspect of the present invention, there is provided a fastener comprising a locking member having a first and second strap accepting channel, each channel comprising locking means, and a strap having a first and second end both of which being receivable by the strap accepting channels so as to fonn a closed loop when the first end is received by the first channel and the second end is received by the second channel.

The fastener preferably comprises two distinct and separate components: a locking member and a strap.

The locking means may be disposed to project into the strap accepting channel.

The locking means may comprise a locking pawl.

The strap may comprise a gripping surface formed thereon for engagement with the locking member.

The gripping surface preferably comprises protrusions complementarily shaped to the locking member. The protrusions may comprise ridges and troughs.

The ridges may have triangular, square, semi-circular, trapezoidal and/or other suitable polygonal profile. Preferably, the protrusions have square profile.

The gripping surface may comprise two or more gripping regions. Each gripping region may have a unique pattern formed by protrusions. The different regions may comprise differently orientated protrusions and/or differently shaped protrusions.

The protrusions in each gripping region may have a different orientation from the other gripping region. This is to ensure that the strap is secured in the correct orientation and the cable tie loop can be closed and tightened around a substrate and the strap is prevented from being withdrawn from each of the channels.

The cable tie is preferably made of a thermoplastic material.

In accordance with a second aspect of the present invention there is provided a kit of parts comprising at least one locking member and a length of strap as described hereinabove.

The strap is preferably provided on a reel. The length of the strap provided on a reel may vary from im to lOm. Alternatively, the strap length may be provided in any suitable length for a particular application.

The locking member may comprise two transverse openings extending these through slightly larger than the strap each for receiving one end of the strap. The openings in the locking member may be defined by a top wall, a bottom wall and a pair of sidewalls.

A locking means may be positioned within the locking member and extend into the openings and is fonned to engage the gripping surface located on the strap to prevent the strap from loosening once the strap is tightened.

The locking means may be partly embedded into the top wall of the channel and the free end extends into the transverse opening, such that one end of the locking device is fixedly moi.mted within the locking member and the other free end acts as a strap retaining device. In one embodiment, the locking means has a region of flexure whereby the strap is easily inserted and pulled through the opening but cannot be withdrawn.

In one embodiment, the locldng member may engage a flexible strap having a row of ratchet teeth on one surface. A locking slot, transverse to the strap, extends through the locking member and may contain a pawl member having ratchet teeth complementary to those on the strap. This transverse slot can be formed between top and bottom end walls and two side walls of the locking member.

One of the channels may have an end wall forming a blind channel into which a strap can be inserted but can only extend a predetermined distance. This prevents a user from wasting strap length which would otherwise extend beyond the channel of the locking member.

The pawl may be att ached to the locking member through a neck. This pawl neck extends upwardly to an enlarged portion which has ratchet teeth complementary to those on the strap. An opening for passage of the strap is thus defined within the locking member between the bottom wall and the pawl teeth. This opening has a width complimentary to the thickness of the strap which ensures that the complementary ratchet teeth engage in an interlocking relationship as the strap is drawn through the transverse slot and tightened around a bundle to be secured.

The improved fastener of the present invention may provide a superior balance of properties because of its unique design over those ties heretofore known.

Although the fastener of the present invention may be moulded from many plastics, one suitable and preferred material is rigid nylon.

The present invention will now be described, by way of example only, with reference to the following figures, in which: Fig. 1 illustrates a first embodiment of the present invention; Fig. 2 illustrates a second embodiment of the present invention; and Fig. 3 illustrates a third embodiment of the present invention.

The cable tie 10 of the present invention includes a strap 12 that has a near end 14 and a tail end 16, and a locking member 20. The strap 12 includes gripping surface 19 formed on the upper surface of the tail end 16. Preferably the gripping surface 19 is formed as a series of ridges. Alternatively, the gripping surface 19 may be a series of indentures which provide a means for locking bundles of elongated items together.

The tail end 16 may be angled and tapered, as shown in FIG. 2, and may also be provided with a pair of longitudinal ridges 17 extending along each side of the strap.

The cable tie is preferably made of integrally molded of thermoplastic material.

The locking member 20, has two transverse openings 22, 22' extending through the locking member 20 slightly larger than strap 12 for receiving the tail end 16 of the strap 12. The transverse opening 22 in locking member 20 is defmed by top wall 24, a bottom wall 26 and a pair of sidewalls 28. A locking means or pawl 32 is positioned within locking member 20 and transverse opening 22 formed to engage the gripping surface 19 located on the tail end 16 of the strap to prevent the strap from loosening once the strap is tightened. The locking means 32 is generally rectangular and extends into the opening 22 at an angle to the axes of the strap 12, such that one end of arching device is fixedly mounted within a locking member and the other free end acts as a strap retaining device. The locking means 32 is slightly narrower than the gripping surface and may be made of metal or other suitable rigid material. A region of flexure between the fixed and free end of locking means 32 allows the strap 12 to be inserted and pulled through the transverse opening 22. The pawl operates as a spring rather than as a hinge during insertion and securing of strap 12.

The pawl 32 has ratchet teeth 34 thereon. Ratchet teeth 34 are complementarily shaped to gripping surface 19 which are fonned on the upper surface of strap 12.

There is a wide latitude of tooth sizes and pitch, and these will vary with certain paranieters including the size of the cable tie 10. It is preferred to produce teeth with the sharpest edges possible during moulding, so that the most effective locking possible is obtained.

Thus, when strap 12 is wrapped around a bundle and the strap inserted through the transverse slot of locking member 20, the complementary sets of ratchet teeth and gripping surface (ridges), 32 and 19, engage each other in an interlocking relationship.

When strap 12 has been pulled tightly around the bundle, the complementary sets of ratchet teeth prevent it from slipping backward to any significant extent. The strap can then be wrapped around the substrate, inserted through the second slot of locking member 20 and pulled tight. After strap 12 has been locked into position, its terminal end may be clipped off so that no portion of strap 12 extends beyond the upper boundaries of locking member 20. The remaining section of strap can then be used with a new locking member 20 to bundle together other substrates.

Thus there is no wastage of strap material.

The protrusions 19 are arranged into two gripping regions: a central region 38, and either side of the central region, two distal edge regions 40.

The protrusion 19 of the central region are iii a different orientation to the distal edge regions which have a common orientation. Distal edge regions are complementarily shaped to locking pawl 32, 34 whilst central region 38 is complimentarily shaped to locking pawl 42 to ensure that strap 12 is only gripped arid retained when the correct locking pawl engages the correct gripping surface.

Fig 2 shows an alternative embodiment where the gripping surface comprises a series of square cross section members and the openings in locking member 20 are disposed one on top of the other.

Fig. 3 shows another embodiment where the gripping surface 19 consists of protrusions having substantially trapezoidal cross-section and engage with teeth 50 of each pawl. The locking member 20 has one transverse opening which is a blind bore defined by end wall 52.

Claims

CLAIMS1. A fastener comprising a locking member having a fast aM second strap accepting channel, each channel comprising locking means, and a strap having a first and second end both of which being receivable by the strap accepting channels so as to form a closed loop when the first end is received by the first channel and the second end is received by the second channel.
2. A fastener as claimed in claim 1 wherein, the fastener comprises two distinct and separate components: a locking member and a strap.
3. A fastener as claimed in claim 1 or 2 wherein the locking means projects into the strap accepting channels.
4. A fastener as claimed in any one of claims I to 4 wherein the locking means comprises a locking pawl.
5. A fastener as claimed in any one of the previous claims wherein the strap comprises a gripping surface formed thereon for engagement with the locking member.
6. A fastener as claimed in claim 5 wherein the gripping surface comprises protrusions substantially complementarily shaped to the locking means so that the strap may be retained by the locking means.
7. A fastener as claimed in claim 6 wherein the protrusions comprise ridges and troughs.
8. A fastener as claimed in claim 7 wherein the ridges have triangular, square, semi-circular or polygonal profile.
9. A fastener as claimed in any one of claims 5 to 8 wherein the gripping surface comprises two or more gripping regions.
10. A fastener as claimed in claim 9 wherein each gripping region has a unique pattern formed from protrusions.
11. A fastener as claimed in claim 10 wherein the different regions comprise differently orientated protrusions and/or differently shaped protrusions.
12. A kit of parts comprising at least one locking member and a length of strap as claimed in any one of the preceding claims.
13. A fastener substantially as described herein with reference to and as illustrated by the accompanying drawings.