GB2528885A

GB2528885A - Tension strap

Info

Publication number: GB2528885A
Application number: GB1413699.8A
Authority: GB
Inventors: Robert Steven Pemberton
Original assignee: Texkimp Ltd
Current assignee: Texkimp Ltd
Priority date: 2014-08-01
Filing date: 2014-08-01
Publication date: 2016-02-10
Also published as: GB201413699D0

Abstract

A tension strap for a fibre tensioner of a creel comprises a first portion 60 with a free end 42 for connection to a fibre tensioner; and a second portion 62 with another free end 44 for connection to the creel frame. A third portion 64 extends between and joins the first and second portions. The strap may encircle a fibre holder bearing surface (58, figure 5) to form a looped strap extending around the bearing surface, the loop comprising the third portion. The strap may be plain and be spirally wrapped around the bearing. Alternatively, the strap may comprise a slot of width W1 which accommodates a reduced width portion W2. The strap may be looped by passing the free end 44 through the slot. The strap may be made from rubber, felt, leather or a woven composite. The straps contacting surface preferably has a friction coefficient of at least 0.5 and may have longitudinal grooves which improve flexibility and aid the dispersal of particles. The strap may be located in a holder bearing track flanked by walls (96). The strap may bear on one to two full circumferences of the holder bearing surface.

Description

TENSION STRAP

The present disclosure relates to a tension strap.

In particular, the disclosure is concerned with a tension strap for a fibre tensioner of a creel.

Background

Figure 1 shows a creel 10 arrangement for the delivery of fibres in a material processing plant. There are many different designs of creel and the one shown in Figure 1 is merely a diagrammatic representation typical of the related art. The creel comprises a support structure 10 upon which are mounted a number of spindles 12 and upon the spindles 12 are carried holders 26 for tubes or bobbins 14. Each holder is supported on its spindle by means of bearings or bushes so that it can rotate to deliver the fibre. The fibre is typically fed from the tubes or bobbins, upon which the fibre is wound, to a processing area 18 where the fibres are processed to produce a desired article or fabric. Two parallel support structures 10 are shown, each delivering fibres 16 to the processing area 18.

Tension must be maintained in the fibres 16 to ensure quality of the final product.

Tension control may be achieved using various arrangements. For example, in figure 2, a tension strap 22 is wrapped part way around a tension strap bearing surface, provided as a pulley 30 which is formed at one end of the holder 26, thereby limiting the rotational freedom of the holder and thus tensioning the fibre. A spring 24 biases the strap 22 onto the surface of the pulley 30. The creel arrangement 10 includes an adjustment feature 28 which allows for the tension of the spring 24 to be altered, with the intention of providing a desired frictional resistance to the rotation of the pulley 30.

Three pulleys 30 are shown with their associated tension straps 22 and tensioning arrangements 28 which include the spring 24.

The problem with this arrangement is also illustrated in Figure 2. If the pulley 30 is perfectly circular, most likely a constant frictional force could be achieved using such an arrangement. However, in practice, due to manufacturing variations, the cross sectional circumference of the pulley 30 is only approximately circular and even a perfectly circular pulley may not be exactly concentric with the central axis of the spindle 12. The three different pulleys 30, shown in Figures 2a, b, c illustrate this point, each being shown having a slightly non-circular and eccentric cross-section. Hence it can be seen that as the pulley 30 rotates the spring 24 must extend and retract to allow for change in the effective radius as the pulley 30 rotates. Thus, the tension applied to the strap 22 by the spring must also change as the pulley rotates. Obviously the non-circularity of the pulleys 30 is exaggerated in Figure 2, but the basic principles holds true for more realistic small manufacturing variations. Hence, a single tension setting using the adjustment feature 28 is not sufficient to achieve a constant resistance as the holder rotates.

Hence an arrangement which is configured to provide a more constant frictional resistance to a holder as it rotates is highly desirable.

Summary

According to the present invention there is provided apparatus as set forth in the appended claims. Other features of the invention will be apparent from the dependent

claims, and the description which follows.

Accordingly there may be provided a tension strap for a fibre tensioner of a creel, the creel comprising a support frame and supporting a fibre holder such that it is rotatable about a rotational axis on the support frame, the holder having a bearing surface; the tension strap being configured to provide frictional resistance to the rotational motion of the holder about the rotational axis, and comprising: a first portion with a free end for connection to an anchor point of the fibre tensioner; a second portion with another free end for connection to the creel support frame; the first portion being joined to the second portion by a third portion which extends between the first portion and the second portion; the third portion being configured to encircle the holder bearing surface to thereby form a looped strap for extending around the holder bearing surface, the ioop comprising the third portion.

The first portion may have a longitudinal slot with: a length equal to or greater than the width of the second portion; and a width equal to or greater than the width of the third portion; such that the free end of the second portion and the third portion can be passed through the slot to thereby form the looped strap for extending around the holder bearing surface, the loop comprising the third and/or first portions.

The width of the first portion may be substantially the same as the width of the second portion, the widths of the first and second portions being substantially constant along their length.

The strap may have a length extending between the first free end and the second free end, a width and thickness, wherein the length is greater than the width, and the width is greater than the thickness, and the thickness is substantially constant along the length of the strap.

The tension strap may comprise at least one of leather, rubber and/or felt.

The tension strap may comprise a dimensionally stable woven composite material.

The inner surface of the tension strap may be configured to bear on the holder comprises longitudinal grooves.

The surface of the tension strap may be configured to bear on the holder bearing surface has a coefficient of friction p of at least 0.5.

There may also be provided a fibre tensioner arrangement for a creel, the creel comprising a support frame and carrying a holder rotatable about a rotational axis on the support frame, the holder having a bearing surface; and a tension strap according to the present disclosure in a looped configuration looped around the bearing surface, the first portion of the tension strap being connected to an anchor point of the fibre tensioner; the second portion of the tension strap being connected to the creel support frame.

The holder bearing surface may comprise a ring shaped track having a rotational axis coaxial with the holder rotational axis; the track being flanked on either side by a wall to maintain the tension strap in a substantially constant position along the holder rotational axis.

The tension strap may be arranged to bear continuously on substantially a full circumference the bearing surface.

The tension strap may be arranged to bear continuously on substantially two full circumferences of the bearing surface.

There may also be provided a creel comprising a fibre tensioner arrangement according

to the present disclosure.

Hence there is provided a tension strap, fibre tensioner and creel configured to maintain a predetermined tension in the strap, and thereby maintain a predetermined frictional resistance to the rotational motion of the holder and hence a predetermined tension in a fibre as it is drawn off the holder.

Brief Description of the Drawings

Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 shows a known creel arrangement; Figure 2 shows a side view of the pulley, strap, spring and adjuster in Figure 1; Figure 3 shows a plan view of a tension strap of the present disclosure; Figure 4 shows the tension strap of Figure 3 formed in a ioop around a pulley of a first design; Figure 5 shows a plan view of the tension strap as shown in Figure 4; Figure 6 shows a tension strap of the present disclosure in situ on a creel having a strap tensioner and showing the holder and pulley, upon which the tension strap bears; and Figures 7 to 10 show an alternative tension strap configuration.

Detailed Description

Figure 3 shows an example of a tension strap 40 of the present disclosure. The tension strap 40 has a length L' extending between a first free end 42 and a second free end 44. The strap 40 also has a width W and T' thickness, where the length "L" is greater than the width "W", and the width "W' is greater than the thickness "T". The thickness "T" of the strap 40 is substantially constant along the length "L" of the strap 40.

The tension strap 40 is for a fibre tensioner arrangement 48 (shown in Figure 6), and the fibre tensioner 48 is for a creel 50 akin to that shown in Figure 1, albeit comprising the improved tension strap 40, 140 and fibre tensioner of the present disclosure. The creel 50 comprises a support frame 52, and the support frame 52 carries a fibre holder 54 which is mounted to be rotatable about a rotational axis 56 defined by a spindle which extends from the support frame on the support frame 52. The holder 54 is provided with a pulley 57 having a bearing surface 58, upon which the load strap 40 is configured to bear.

The tension strap 40 is configured to provide frictional resistance to the rotational motion of the pulley 57. The tension strap comprises a first portion 60 which extends from the free end 42, where the free end 42 is to provide a connection to an anchor point 80 on the strap tensioner 48 as described later in relation to Figure 6. The tension strap 40 further comprises a second portion 62 having another free end 44 for connection to the creel support frame 52. The first portion 60 is joined to the second portion 62 by a third portion 64 which extends between the first portion 60 and the second portion 62. Although the strap 40 is described as comprising "portions" (ie regions), it may be substantially continuous in construction. That is to say, the different portions/regions 60, 62, 64 are formed integrally with one another. The first portion 60 is provided with a longitudinal slot 66. The slot has a length Li' aligned with the longitudinal length "L' of the strap 40. The slot also has a width Wi aligned with the width W of the strap 40. Likewise the third portion of the strap has a length L2 aligned with the length "L" of the strap 40, and a width W2 aligned with the width of the strap 40. The longitudinal slot 66 has a width Wi greater than the width W2 of the third portion 64. The sizes of the portions of the strap 40 are chosen such that the free end 44 of the second portion 62 and the third portion 64 can be passed through the slot 66 to thereby form a looped strap for extending around the pulley surface 58. The loop formed by the strap 40 comprises the third portion 64 and/or first portion 60. When in situ the free ends 42, 44 may extend in different directions to one another, for example in opposite directions.

The width W of the first portion 60 is substantially the same as the width W of the second portion 62, the widths of the first and second portions being substantially constant along their length.

The tension strap 40 is made from a flexible material which exhibits minimal stretch and is wear resistant. It also has a high coefficient of friction against the pulley surface 58.

Suitable materials may include, but are not limited to, leather, rubber and felt. The tension strap may also comprise a composite material, including a woven fabric to improve the dimensional stability of the strap.

The tension strap comprises an outer surface 72 which, in use, faces away from the pulley bearing surface 58, and an inner surface 74 which faces towards the pulley bearing surface 58.

The inner surface of the strap 40 may have features such as grooves 75. The grooves may be aligned with the longitudinal length L of the strap, as shown in Figure 3.

These may improve flexibility and aid the dispersal of particles generated as a result of wear, or deposited from the surrounding atmosphere.

The inner surface 74 of the tension strap 40 will generally have a coefficient of friction p of at least 0.5 on the pulley bearing surface 58.

Figure 4 is a side view showing a cross section of the pulley 57 and tension strap 40. It shows the tension strap 40 in a loop configuration around the bearing surface 58 of the pulley 57. Figure 5 shows a plan view of the strap 40 in a looped configuration, with the second portion 62 and third portion 64 passed through the longitudinal slot 66 in the first portion 60 of the strap 40. As can be seen in Figure 4, having the tension strap 40 in this looped configuration means that the strap is in contact with the outer surface of the spindle bearing surface 58 around the entire circumference of the spindle pulley bearing surface 58. That is to say, the strap 40 extends substantially 360° around the circumference of the pulley bearing surface 58.

Figure 6 shows an example with the detail of a pulley 57 and strap tensioner 48 arrangement.

In the example shown, the strap tensioner 48 comprises a spring 82 which is connected at one end to the free end 42 of the strap 40. The spring 82 is connected at its other end to an adjustment feature 84. The adjustment feature 84 allows for the movement of the end of the spring 82 relative to the holder 54. The adjustment feature 84 may be moved further away from the holder 54 to tighten the strap 40 or brought closer to the holder 54 to decrease the tension in the strap 40. The arrow marked as 88 in Figure 6 indicates the direction in which the spring 82 in this example may be moved forwards and away from the holder 54.

The pulley 57 may be flanked on either side by a wall 96 to maintain the tension strap in a substantially constant position when the strap tensioner is fully relaxed.

Other tension mechanisms may be also used to tension the strap. The loop strap arrangement of the present disclosure provides significant advantages and performance in configurations where the strap tension will be affected by movement of the free end of the strap 40 whatever tensioning system is provided. The significant feature of this arrangement is that the tension strap 40 is arranged to bear on substantially a whole circumference of the pulley surface 58.That is to say, the strap 40 bounds and surrounds the pulley 30 entirely (i.e. throughout the complete 360° circumference of the pulley surface). This is similarly true for the example of Figures 7 to 10.

Figures 7 to 10 show an alternative example of tension strap 140 according to the present disclosure, and suitable for use with the fibre tensioner 48 and creel 50 as previously described. Features common to the preceding example of the present disclosure are referred to using the same reference numerals. Only part of the holder 54 is shown in Figure 7, which should be viewed in conjunction with figure 6. In order to show the detail of the strap 140, figures 7 to 10 show only the part of the pulley 57 which provides the bearing surface 58.

As with the example of Figures 3 to 6, the tension strap 140 extends between a first free end 142 and a second free end 144. The tension strap 140 is configured to provide frictional resistance to the rotational motion of the pulley 57 by bearing on the pulley surface 58. The tension strap 140 comprises a first portion 160 which extends from the free end 142, where the free end 142 is to provide a connection to the spring 82 of the strap tensioner 48 (as shown in figure 6). The tension strap 40 further comprises a second portion 162 having another free end 144 for connection to the creel support frame 52 (as shown in Figure 6). The first portion 160 is joined to the second portion 162 by a third portion 164 which extends between the first portion 160 and the second portion 162. Although the strap 140 is described as comprising portions" (ie regions), it may be substantially continuous in construction. That is to say, the different portions/regions are formed integrally with one another.

As shown in Figures 7 to 10, the third portion 164 is configured to encircle the pulley 57 bearing surface 58 to form a looped strap that extends around the pulley bearing surface 58, the loop comprising the third portion 164. In figures 7 to 10 the strap 140 is shown as a single loop, and is thus arranged to bear continuously on substantially a full circumference the bearing surface.

In an alternative example, the strap may encircle the pulley surface 58 two or more times. That is to say, the tension strap 140 may be arranged to bear continuously on substantially two or more full circumferences of the bearing surface 58. Put another way, the tension strap 140 may be arranged such that it forms at least a 720 degree loop such that it may bear continuously on substantially two or more full circumferences of the pulley surface 58.

The primary benefit of the examples of the present disclosure herein described is that the effects of non-circularity or eccentricity of the pulley on the tensioning device are minimized.

Where the strap encircles one or more complete turns of the pulley, the length of the arc described by the strap is constant and the change in tension in the strap 40,140, and hence the fibre 16, is minimized.

Thus the tension strap, fibre tensioner arrangement and creel of the present disclosure provide the advantage that in combination they provide a substantially constant tension in a tension strap, and hence the tension strap can provide substantially constant frictional force acting on a pulley around which the tension strap is wrapped, to maintain a constant tension force in a fibre 16 being drawn off the holder to which the pulley is attached.

A device comprising a tension strap of the present disclosure, as well as the spindle tensioning arrangement made possible by the tension strap arrangement 40 of the present disclosure, is thus able to provide constant and predictable fibre tension when the eccentricity or circularity of the pulley is variable due to production or manufacturing limitations.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMSA tension strap for a fibre tensioner of a creel, the creel comprising a support frame and supporting a fibre holder such that it is rotatable about a rotational axis on the support frame, the holder having a bearing surface; the tension strap being configured to provide frictional resistance to the rotational motion of the holder about the rotational axis, and comprising a first portion with a free end for connection to an anchor point of the fibre tensioner; a second portion with another free end for connection to the creel support frame; the first portion being joined to the second portion by a third portion which extends between the first portion and the second portion; the third portion being configured to encircle the holder bearing surface to thereby form a looped strap for extending around the holder bearing surface, the loop comprising the third portion.
2 A tension strap for a fibre tensioner of a creel as claimed in claim 1 wherein the first portion has a longitudinal slot with a length equal to or greater than the width of the second portion; and a width equal to or greater than the width of the third portion; such that the free end of the second portion and the third portion can be passed through the slot to thereby form the looped strap for extending around the holder bearing surface, the ioop comprising the third and/or first portions.
3 A tension strap as claimed in claim 2 wherein: the width of the first portion is substantially the same as the width of the second portion, the widths of the first and second portions being substantially constant along their length.
4 A tension strap as claimed in claim 2 or claim 3 wherein the strap has a length extending between the first free end and the second free end, a width and thickness, wherein the length is greater than the width, and the width is greater than the thickness, and the thickness is substantially constant along the length of the strap.
A tension strap as claimed in any one of the preceding claims wherein the tension strap comprises at least one of leather, rubber and/or felt.
6 A tension strap as claimed in any one of the preceding claims wherein the tension strap comprises a dimensionally stable woven composite material.
7 A tension strap as claimed in any one of the preceding claims wherein the inner surface of the tension strap configured to bear on the holder comprises longitudinal grooves.
8 A tension strap as claimed in any one of the preceding claims wherein the surface of the tension strap configured to bear on the holder bearing surface has a coefficient of friction p of at least 0.5.
9 A fibre tensioner arrangement for a creel, the creel comprising a support frame and carrying a holder rotatable about a rotational axis on the support frame, the holder having a bearing surface; and a tension strap as claimed in any one of claims 1 to 8 in a looped configuration looped around the bearing surface, the first portion of the tension strap being connected to an anchor point of the fibre tensioner; the second portion of the tension strap being connected to the creel support frame.
A fibre tensioner as claimed in claim 9 wherein the holder bearing surface comprises a ring shaped track having a rotational axis coaxial with the holder rotational axis; the track being flanked on either side by a wall to maintain the tension strap in a substantially constant position along the holder rotational axis.
11 A fibre tensioner as claimed in claim 9 or claim 10 wherein the tension strap is arranged to bear continuously on substantially a full circumference the bearing surface.
12 A fibre tensioner as claimed in claim 10 or claim 11 wherein the tension strap is arranged to bear continuously on substantially two full circumferences of the bearing surface.
13 A creel comprising a fibre tensioner arrangement as claimed in any one of claims 9 to 12.
14 A tension strap for a fibre tensioner of a creel substantially as hereinbefore described and/or as shown figures 3 to 10.
A fibre tensioner arrangement for a creel substantially as hereinbefore described and/or as shown figures 3 to 10.
16 A creel substantially as hereinbefore described and/or as shown figures 3 to 10.Amendments to the Claims have been filed as follows;CLAIMS1 A creel comprising: a support frame supporting a fibre holder such that it is rotatable about a rotational axis on the support frame: the holder having a bearing surface; and a fibre tensioner provided with a tension strap configured to provide frictional resistance to the rotational motion of the holder about the rotational axis, the tension strap comprising a first portion with a free end connected to an anchor point of the fibre tensioner; LCD a second portion with another free end connected to the creel support 0 frame; a) 1 the first portion being joined to the second portion by a third portion which extends between the first portion and the second portion; the third portion encircling the holder bearing surface to thereby form a looped strap for extending around the holder bearing surface, such that the tension strap is arranged to bear continuously on substantially a full circumference the bearing surface, the loop comprising the third portion.2 A creel as claimed in claim 1 wherein the first portion of the tension strap has a longitudinal slot with a length equal to or greater than the width of the second portion; and a width equal to or greater than the width of the third portion; such that the free end of the second portion and the third portion can be passed through the slot to thereby form the looped strap for extending around the holder bearing surface.3 A creel as claimed in claim 2 wherein the width of the first portion is substantially the same as the width of the second portion, the widths of the first and second portions being substantially constant along their length.4 A creel as claimed in claim 2 or claim 3 wherein the strap has a length extending between the first free end and the second free end, a width and thickness, 0 wherein the length is greater than the width, and the width is greater than the thickness, and the thickness is substantially constant along the length of the strap.A creel as claimed in any one of the preceding claims wherein the tension strap comprises leather, rubber and/or felt.6 A creel as claimed in any one of the preceding claims wherein the tension strap comprises a dimensionally stable woven composite material.7 A creel as claimed in any one of the preceding claims wherein the inner surface of the tension strap configured to bear on the holder comprises longitudinal grooves.8 A creel as claimed in any one of the preceding claims wherein the surface of the tension strap configured to bear on the holder bearing surface has a coefficient of friction p of at least 0.5.9 A creel as claimed in any one of the preceding claims wherein: the holder bearing surface comprises a ring shaped track having a rotational axis coaxial with the holder rotational axis; the track being flanked on either side by a wall to maintain the tension strap in a substantially constant position along the holder rotational axis.A creel as claimed in any one of the preceding claims wherein: U) the tension strap is arranged to bear continuously on substantially two full circumferences of the bearing surface. LtD11 A tension strap for a fibre tensioner of a creel substantially as hereinbefore described and/or as shown figures 3 to 10. r12 A fibre tensioner arrangement for a creel substantially as hereinbefore described and/or as shown figures 3 to 10.13 A creel substantially as hereinbefore described and/or as shown figures 3 to 10.