GB2308153A

GB2308153A - Flexible tie for cables

Info

Publication number: GB2308153A
Application number: GB9610120A
Authority: GB
Inventors: Kenneth Christian; Mark Federspiel; Steven John Blanks
Original assignee: Bowthorpe PLC; Tyton Corp
Current assignee: Bowthorpe PLC; Tyton Corp
Priority date: 1995-12-13
Filing date: 1996-05-15
Publication date: 1997-06-18
Anticipated expiration: 2016-05-15
Also published as: GB9610120D0; FR2742489B1; US5890265A; FR2742489A1; GB2308153B

Description

Parallel Entrv Tie This invention relates to flexible ties and, more particularly, ties of the parallel entry type.

Flexible ties for use in bundling elongated members such as wires, cables, etc. are well known. Typically, such ties include an elongated flexible strap made of a suitable plastics material. The tie usually has a free end and a locking mechanism at the opposite end. The strap is capable of being turned on itself 3600 for insertion into the locking head after which the diameter of the loop thus formed can be adjusted to snugly fit over the intended bundle.

A parallel entry tie is one wherein the insertion of the strap into the locking head and then its extension into and through the locking head is generally in alignment with the loop which is formed, as opposed to being at a lateral angle to the loop.

Various constructions of parallel entry ties have been proposed. The desirable characteristic in any tie, and particularly so in a parallel entry tie, is a low insertion force while obtaining a positive and reliable connection of the strap in the locking head to maintain the adjusted loop diameter. For the most part, prior ties of this type have been lacking in either one or both of those characteristics.

It is, therefore, an object of this invention to provide a new and improved tie, particularly a parallel entry tie, which demonstrates desirable holding characteristics as well as a low insertion force.

For the achievement of those and other objects, this invention proposes a flexible tie construction including a strap and a locking head which receives the free end of the strap when the strap is looped. The strap is received in a passage in the locking head for selective engagement by a pawl supported on the locking head, the pawl having a bias toward and into the passage. The pawl then engages the strap as the strap passes into and through the passage and selectively engages serrations on the strap to prevent withdrawal of the tie from the locking head. The strap can be released for withdrawal from the locking head by moving the pawl against the bias. The pawl is attached to a first rib by a hinge section that biases the pawl into a first position and the pawl abuts the first rib when the strap is tensioned.

An opening is provided in the locking head generally opposite to the location of the pawl. The strap, throughout the major portion of its extension, has a width which is preferably no greater, or less, than the width of the opening. The opening in the locking head is preferably provided with spaced shoulders in the area of engagement between the pawl and the strap serrations.

Also in the preferred embodiment, an inclined lip is provided in the area through which the strap exits the locking head. The lip is angled such as to displace the strap from the normal extension of the passage and the strap adjacent the locking head.

Embodiments of this invention will now be described by way of example only, and with reference to the accompanying drawings in which: Figure 1 is a plan view of parallel entry tie in accordance with this invention; Figure 2 is a side view of the tie of Figure 1; Figure 3 is a longitudinal sectional view through opposite ends of the flexible tie of Figure 1, prior to inserting the strap into the head; Figure 4 is a sectional view similar to Figure 3, when the strap is being inserted into the head; Figure 5 is a bottom view of the tie of Figure 1; Figure 6 is a bottom view of the tie of Figure 3, when the tie is tied; Figure 7 is a plan view of the head of an alternative embodiment of tie in accordance with this invention; and Figure 8 is a sectional view along the line VIII - VIII of Figure 7.

Referring to Figures 1 and 2 of the drawings, there is shown an embodiment of parallel entry tie comprising a strap 8 including a free end 10 and a locking head 12 disposed at its opposite end. A series of serrations 14 are provided along a length of the strap 8, on one side thereof.

As can be seen in Figure 1, in its normal or first state, the strap 8 has a general extension along a longitudinal axis 16. In a conventional manner, and therefore not shown, the strap 8 can be looped on itself to position the free end 10 at the locking head 12. This is partially illustrated in Figures 3, 4 and 5 that is, the free end 10 is shown as being at and then ultimately in and through the locking head 12 but the remaining looped portion of the strap 8 has not been illustrated.

Referring to Figure 3 of the drawings, the locking head 12 includes a passage 24 having an entrance end 18 and an exit end 20. The passage 23 comprises side walls 26 and 28, which protect from the serrated side of the strap 8, and a bottom wail 22, which is generally in alignment with the normal extension of the strap 8. Side walls 26 and 28 have thereon ribs 29 which act as finger grips to enable the locking head 12 t be more securely held by the user, when securing the tie.

The bottom wall 22 of the passage comprises an opening 34 disposed between a pair of ribs 30 and 32. A rib 54 is provided between side walls 26 and 28 at the exit end 20 of the locking head 12. Rib 54, in co-operation with rib 32, insures effective movement of the free end 10 of the strap 8 through passage 24 and out of exit end 20. An opening 56 is provided in the bottom wall 22 between rib 32 and another rib like portion 58, with that opening being generally opposite to rib 54. This arrangement again enhances the reduction in the insertion force required to move the free end 10 of the strap 8 through the locking head 12.

A pawl 36 is positioned opposite to opening 34 and is connected to a rib 38 which extends between the side walls 26 and 28. The pawl 36 has thereon a plurality of teeth 44. The connection between pawl 36 and rib 38 is through a hinge section 40. The hinge section 40 produces a natural bias on the pawl 36 in a clockwise direction as viewed in Figures 3, 4 and 6. When the free end 10 of the strap 8 is not in passage 24, the pawl 36 assumes the normal or first position as viewed in Figure 3.

As the free end 10 of the strap 8 is inserted into the passage 24 as shown in Figure 4, the pawl 36 moves from its first position to a second position in which the hinge section 40 provides that only one tooth 44A of the pawl 36 engages the serrations 14 and the pawl 36 is moved in a counterclockwise direction, against the bias to enable the tooth 44A to sequentially ride over the serrations 14. With only one tooth 44A riding over the serrations 14, the insertion force of the free end 10 of the strap 8 into the passage 24 is minimised in accordance with this invention.

When the free end 10 of the strap 8 comes to rest in any position in the passage 24 and the free end 10 is tensioned, there will be a back-force on the strap 8 attempting to pull the free end 10 toward the entrance end 18 in the withdrawal direction. The force will move the pawl 36 in a clockwise direction thus engaging all of the teeth 44 with the serrations 14. In this tied condition as shown in Figure 6, the surface 39 of rib 38 abuts or is in engagement with the opposed surface 41 of the pawl 36, so that the tension forces applied to the strap 8 are directly transmitted from the pawl 36 to the rib 38. In the locked position, withdrawal of the free end 10 from the passage 24 is prevented.

As shown in Figure 6, tip portion 42 at the end of the pawl 36 allows for ready release of the free end 10 of the strap 8 from the passage 24. To release the free end 10, the tip portion 42 is lifted upwardly to disengage the teeth 44 from the serrations 14 and allow the free end 10 to be removed from passage 24. This release feature is important in instances where strap 8 is reusable or is used in an application where cutting the free end 10 may expose the surrounding material to damage. In an alternative embodiment, if the strap 8 does not need to be releasable, the tip portion 42 can be omitted from pawl 36.

Referring to Figure 1, the pawl 36 has on its top surface 43 two stops 45, which limit the upward and counterclockwise movement of the pawl 36, so that when the free end 10 is being released from the passage 24, the pawl 36 is not overextended or damaged.

With reference to Figures 1 and 5 of the drawings, the free end 10 of strap 8 has a width W1 which is generally uniform along the major extension of the free end 10 but which tapers down to a lesser width in an area A adjacent the free end 10. Opening 34 has a width W2 which, in the preferred embodiment, is selected to be greater than the width W1.

The provision of the opening 34 in the locking head 12 and particularly in the area of the pawl 36, reduces the force required to insert the free end 10 into and then through the passage 24. By providing opening 34 with a width W2 which is greater than the width W1 of the free end 10, the lowering of the insertion force is further enhanced.

Referring again to Figure 5, a pair of spaced shoulders 46 and 48 are provided in opening 34 and in the area of the pawl 36. The width of the pawl 36 is less than the width W3 of the opening between the shoulders 46, 48. The pawl 36 is disposed substantially over the opening between the shoulders 46, 48, such if a pulling force is applied to the tie once it is secured, the pawl 36 will move in a clockwise direction and deform the strap O out of its plane between the shoulders. The shoulders 46, 48 serve to support the sides of the strap 8, and thus prevent it from disengaging from the pawl 36, without materially increasing the insertion force. The deformed portion of the strap acts rather like a stud in the opening 34, and thereby helps to lock the strap 8 to the head 12.

With reference to Figure 4 of the drawings, it will be noted that an alternate embodiment of strap 8 includes an inclined lip 50. The surface 52 of the lip 50 is inclined away from the bottom wall 22 and projects into the extension of passage 24. Therefore, the free end 10 of the strap 8 is displaced from the normal extension of the passage 24 as it exits the locking head 12. This makes the free end 10 readily accessible after the bundle diameter has been selected in the event it is desirable to sever the free end 10. Rib 54 is provided with an inclined surface 60 to better accommodate the movement of the free end 10 as it engages surface 52 and is displaced upwardly from the normal direction of passage 24. The combination of ribs 30, 32, 38, 54 and 5, together with the pawl 36 and side walls 26, 28 form the passage 24.

The tie is manufactured by injection moulding from a plastics material using two dies defining a mould cavity and separable in a straight line perpendicular to the plane of the strap. The aperture 34 enables an upwardly projecting mould core in the lower die, which forms the underside of pawl 36, to be withdrawn from the head after moulding.

A disadvantage of moulded plastics parallel entry ties is that the pawl 36 is accessible from above, owing to the aforementioned way in which the tie is moulded. Thus, the ties are relatively insecure in that the pawl 36 can be levered away from the strap, in order to release the tie.

Referring to Figures 7 and 8 of the drawings, there is shown an alternative embodiment of parallel entry tie and like parts are given like reference numerals. The tie comprises a one-piece body 80, substantially as hereinbefore described, and a cover 70 which fits onto the head, and which prevents access to the pawl 36.

The cover 70 comprises a flat top wall 71, which extends over the head, generally parallel to the plane on the strap 8. Opposite side-walls 73, 74 depend from the respective opposite sides of the top wall 71 of the cover over respective sidewalls 26, 28 of the head 12. Outer and inner end walls 75, 76 depend from the respective ends of the top wall 71 of the cover over the outer and inner end faces of the head respectively. Slots 77, 78, formed in the outer and inner end walls 75, 76 of the cover respectively, align with the entrance and exit ends 18, 20 of the passage 24 respectively.

In the embodiment shown, the cover 70 is formed separately from the body 80, so that it can be made from a different colour plastics material, e.g. for identification or promotional purposes. The upper surface of the top wall 71 of the cover 70 may be formed with a logo or other indicia.

Accordingly, it is preferable to form the cover separately from the rest of the tie, so that only stocks of each cover and one body have to be carried, as opposed to stocks of different ties. Furthermore, this arrangement reduces tooling costs.

In order to attach the cover 70 to the body 80, the lowermost part of the outer end wall 75 of the cover is engaged over the outermost rib 30 on the bottom wall 22 of the passage 24. The cover 70 is then pivoted over the head 12 until a pair of lugs 79 on opposite sides of its inner end wall engage over respective tabs 81 which project from opposite side edges of the strap 8.

When the tie is tied the strap 8 extends through the slot 77 in the outer end of the cover, the passage 24 and the slot 78 in the inner end of the cover. It is not possible to release the tie once it has been fastened, because the cover 70 prevents access to the pawl 36. Furthermore, it is not possible to remove the cover, because it is locked onto the head by the strap 8, which passes through the slots 77,78 at opposite ends of the head passage 24, when the tie is tied.

In an alternative embodiment the whole tie may be formed as a one-piece, with the cover 70 being joined to the rib 30 of the head by a flexible web, which perils the cover to be hinged over the head after moulding.

Claims

1) A flexible tie comprising an elongate strap having a free end and an opposed second end, said second end having thereon a locking head, said strap having thereon serrations and said strap being turnable on itself to position said free end at said locking head, said locking head having therethrough a passage having an entrance end and an exit end, said passage being formed by spaced sidewalls extending in the direction of elongation of said strap and spaced first and second ribs extending between said sidewalls, said first and second ribs and said sidewalls defining an opening, a pawl attached to said first rib by a hinge section that biases said pawl in a first position, said pawl having thereon a plurality of teeth, said pawl being moveable from said first position to a second position by movement of said strap into said passage wherein only one of said plurality of teeth engage said serrations on said strap when said pawl is in said second position, and said pawl being moveable from said second position to a locking position by a load being applied to said strap wherein in said locking position, said pawl abuts said first rib and said plurality of teeth engage said serrations to oppose withdrawal of said strap from said passage.

2) A flexible tie as claimed in claim 1, wherein said pawl includes a tip portion and wherein when said pawl is in said locking position, said tip is movable upwardly away from said locking head to disengage said pawl and said serrations and thereby permit said strap to be withdrawn from said passage.

3) A flexible tie as claimed in claims 1 or 2, wherein said pawl has thereon at least one stop adjacent said first rib and wherein upward movement of said locking head is limited by said stop abutting said first rib.

4) A flexible tie as claimed in any preceding claim, wherein said sidewalls of said locking head have thereon ribs.

5) A flexible tie comprising an elongate, generally flexible strap, said strap having a free end and a locking head spaced from said free end and said strap being flexible to be turned on itself to position said free end at said locking head, and said strap including a plurality of serrations spaced along said strap, said locking head having an entrance end, an exit end spaced from said entrance end, and a passage extending between said entrance end and said exit end, said passage formed by spaced sidewalls extending in the direction of elongation of said strap and spaced ribs extending between said sidewalls, first and second of said ribs being generally aligned with said strap and disposed on one side of said passage, said first rib being located adjacent said entrance end, said second rib being spaced from said first rib in the direction of said exit end, a first opening being defined between said first and second ribs, third and fourth of said ribs disposed on the other side of said passage, said third rib being located adjacent said entrance end, said fourth rib being spaced from said third rib in the direction of said exit end, a second opening being defined between said third and fourth ribs, and a pawl supported by said third rib and located in said second opening, said pawl being biased to assume a first position extending into said passage, said pawl being movable against said bias away from said first position and into a second position by movement of said strap in said passage, and said pawl being moveable from said second position into a locking position by a load applied to said strap, in said locking position, said pawl interengages with said serrations to oppose withdrawal of said strap from said locking head.

6) A flexible tie as claim in claim 5, wherein said first opening has an extension in the direction of the extension of said passage and a width which is transverse to said extension, and ..herein the width of said strap is less than the width of said first opening.

7) A flexible tie as claimed in 5 or 6, and further including a lip adjacent said exit end and inclined to the extension of said passage to engage and displace said strap as said strap exits said locking head.

8) A flexible tie as claimed in any of claims 5 to 7, wherein said pawl is attached to said third rib by a hinge section.

9) A flexible tie as claimed in any of claims 5 to 8, and further including first and second shoulders located one on each side of said first opening and each shoulder extending into said opening but terminating in said first opening in spaced relation from each other and in alignment with each other.

10) A flexible tie as claimed in any of claims 5 to 9, further including a fifth rib adjacent said exit end and spaced from said second rib to define a third opening therebetween, said third opening being generally opposed to said fourth rib.

11) A flexible tie as claimed in any of claims 5 to 10, wherein said pawl has thereon a plurality of teeth which are engagable with said serration of said strap and wherein only one of said plurality of teeth engage said serrations when said pawl in said second position.

12) A flexible tie as claimed in any of claims 5 to 11, wherein said pawl abuts said third rib when said pawl is in said locking position.

13) A flexible tie as claimed in any of claims 5 to 12, wherein said pawl includes a tip extending out of said second opening and wherein when said pawl is in said locking positions, said tip is movable upwardly away from said locking head to disengage said pawl and said serrations and permit said strap to be withdrawn from said passage.

14) A flexible tie as claimed in any of claims 5 to 13, wherein said pawl has thereon at least one stop adjacent said third rib wherein upward movement of said pawl is limited by said stop abutting said third rib.

15) A flexible tie as claimed in any of claims 5 to 14, wherein said sidewalls of said locking head have thereon ribs.

16) A flexible tie of moulded plastics material comprising a flexible elongate strap formed on one side thereof with a series of serrations, a head at one end of the strap, a passage extending through the head generally in the direction of the axis of the strap, and having an entrance end and an exit end disposed axially inwardly of the entrance end, a pawl disposed to form part of a side of the passage and being provided with a plurality of teeth for engaging the strap serrations when the strap is inserted through the passage, and a cover for attaching to the head and arranged to cover the pawl, the cover comprising an opening at one end which co-extends with the passage at the exit end thereof when the cover member is attached to the head, the strap extending through the passage and said opening in the cover when the tie is secured, thereby preventing the cover member from being detached.

17) A flexible tie as claimed in claim 16, in which the head and the strap comprise a one-piece member.

18) A flexible tie as claimed in claim 17, in which the cover is a separate member from the head and strap member.

19) A flexible tie as claimed in claim 18, in which the cover is a different colour from the strap and head member.

20) A flexible tie as claimed in claim 16, in which the tie is formed as a one-piece member.

21) A flexible tie as claimed in claim 20, in which the opposite end of the cover is hinged to the head.

22) A flexible tie as claimed in any of claims 16 to 21, in which the cover member comprises an opening at its opposite end which co-extends with the passage at the entry end thereof, when the cover member is attached to the head.

23) A flexible tie as claimed in any of claims 16 to 22, in which said end of the cover snap engages with the head.

24) A flexible tie comprising an elongated, generally flexible strap, said strap having a free end and a locking head spaced from said free end and said strap being flexible to be turned on itself to position said free end at said locking head, and said strap including a plurality of serrations spaced along said strap, said locking head having an entrance end, an exit end spaced from said entrance end, and a passage extending between said entrance end and said exit end, said passage formed by spaced sidewalls extending in the direction of elongation of said strap and spaced ribs extending between said sidewalls, first and second of said ribs being generally aligned with said strap and disposed on one side of said passage, said first rib being located adjacent said entrance end, said second rib being spaced from said first tab in the direction of said exit end, a first opening being defined between said first and second ribs, third and fourth of said ribs being generally aligned with said strap and disposed on the other side ot said passage, said third rib being located adjacent said entrance end, said fourth rib being spaced from said third rib in the direction of said exit end, a second opening being defined between said third and fourth ribs, and a pawl attached to said first rib by a hinge section that biases said pawl in a first position, said pawl having thereon a plurality of teeth, said pawl being moveable from said first position to a second position by movement of said strap into said passage wherein only one of said plurality of teeth engage said serrations on said strap when said pawl is in said second position, and said pawl being moveable from said second position to a locking position by a load being applied to said strap wherein in said locking position, said pawl abuts said third rib and said plurality of teeth engage said serrations to oppose withdrawal of said strap from said passage, said pawl includes a tip portion and wherein when said pawl is in said locking position and said tip is moved upwardly away from said locking head, said pawl and said serrations disengage and said strap is withdrawable from said passage, said pawl has thereon at least one stop adjacent said third rib and wherein upward movement of said locking head is limited by said stop abutting said third rib.

25) A flexible tie as claimed in claim 24, wherein said sidewalls of said locking head have ribs thereon.

26) A flexible tie as claimed in claims 24 or 25, wherein said first opening has an extension in the direction of the extension of said passage and a width which is transverse to said extension, and wherein the width of said strap is less than the width of said first opening.

27) A flexible tie as claimed in any of claims 24 to 26, and further including a lip adjacent said exit end and inclined into the extension of said passage to engage and displace said strap as said strap exits said locking head.

28) A flexible tie substantially as herein described with reference to Figures 1 to 6 or Figures 7 and 8 of the accompanying drawings.