GB2490951A

GB2490951A - A grommet with an outer rim cover for a string

Info

Publication number: GB2490951A
Application number: GB1108441.5A
Authority: GB
Inventors: Richard Andrews
Original assignee: Dunlop Slazenger International Ltd
Current assignee: Dunlop International Europe Ltd
Priority date: 2011-05-19
Filing date: 2011-05-19
Publication date: 2012-11-21
Also published as: CN202983090U; GB201108441D0

Abstract

A grommet for the frame of a sports racket comprising first 14 and second 16 spaced hollow members each with an open distal end and an outer rim portion 28 extending between the hollow members wherein the outer rim 28 defines a string path between the hollow members 14 and 16 such that the rim portion 28 covers the string path. The outer rim portion 28 may be a detachable cap. The hollow members 14 and 16 may run parallel to each other and be tubular. There may be an elastomeric damping element 36 on the outside of the grommet. Also claimed is a racket with a grommet wherein the grommet conforms to the shape of the racket.

Description

GROMMET

The invention relates to a grommet for a frame of a sports racquet, in particular, although not exclusively, to a grommet having a main body and a cap, the cap providing an outer rim portion that in use covers the string.

Sports racquets such as tennis racquets, for example, typically comprise a frame having a handle and a frame head. The frame head defines an open head portion of the racquet which is strung to provide a mesh of main strings, which extend in the longitudinal direction of the handle, and cross strings, which are perpendicular to the main strings. Various different types of strings can be used to alter the performance of the racquet. Further, the strings can be tensioned in order to provide different playing characteristics.

The frame head is provided with string openings through which strings are passed in order to string the racquet. It is desirable to isolate the strings from the frame head itself in order to avoid damaging the strings. A grommet is therefore typically provided for this purpose. The grommet typically comprises a strip of plastic having a plurality of hollow plastic tubes extending therefrom. The openings in the hollow tubes extend completely through the grommet strip. In use, the grommet is located in a recess that extends around the rim of the racquet with the hollow tubes disposed in the string openings of the racquet. When the racquet is strung, the strings pass through the hollow tubes and over the outside of the grommet strip. The grommet strip and the hollow tubes therefore prevent the strings from coming into contact with the frame itself.

Whilst this is entirely satisfactory for many applications, the grommet strip and stringing arrangement may be aesthetically unappealing and/or may cause aerodynamic drag.

It may therefore be desirable to provide an improved grommet and sports racquet which aims to address at least some of the above problems.

In a broad aspect the invention concerns an outer rim portion of a grommet for a sports racquet which in use is arranged to cover a racquet string.

According to an aspect of the invention there is provided a grommet for a frame of a sports racquet, comprising: a main grommet portion comprising: first and second spaced hollow members that each have an open distal end; and an outer rim portion extending between the proximal ends of the first and second spaced hollow members; wherein the outer rim portion defines a rim string path between the proximal ends of the first and second hollow members that is radially inwards of the outer rim portion, so that in use a racquet string extending along the rim string path is covered by the outer rim portion. In use, a string would extend through the grommet from the open distal end of the first hollow member to the open distal end of the second hollow member and along the rim string path between the proximal ends of the first and second hollow members. Since the rim string path is radially inwards of the outer rim portion with respect to the sports racquet, the outer rim portion completely covers a string extending through the grommet. This may result in a smooth surface profile of the racquet which may improve the aerodynamic properties of the racquet. Further, the structure of the grommet may allow the outer surface of the grommet and the frame to be coated with a continuous layer of resin and/or paint. This may result in the grommets not being visible in use and therefore may improve the aesthetic appearance, and aerodynamic properties of the racquet. Although it has been described that the grommet has first and second hollow members, the grommet may have any number of hollow members, for example three, four, five or ten.

The main grommet portion may further comprise an inner rim portion, the outer and inner rim portions providing a rim string conduit defining a substantially enclosed rim string path. The inner rim portion would prevent a string extending through the grommet from coming into contact with the frame of the racquet. The grommet would therefore completely isolate the string from the racquet. The inner and outer rim portions may be separate from one another, or may be integrally formed with the first and second hollow members. For example, there may be a hollow rim portion, such as a tube, extending between the first and second hollow members and providing the inner and outer rim portions.

The main grommet portion may comprise a main body comprising the first and second hollow members and the inner rim portion, and a cap comprising the outer rim portion.

The main body and the cap may be discrete components. This may allow the grommet to be manufactured with ease. Further, it may allow the racquet to be strung more easily. The main body and the cap may be each integrally formed. The main body and!or the cap may be an injection moulded component comprising a plastics material.

The cap may be detachably attached to the main body. This may allow the cap to remove so that the racquet could be strung, or restrung, more easily. The first and second hollow members and/or the inner rim portion and/or the outer rim portion may be flexible.

The rim string path may be defined by a hollow rim portion providing a rim string conduit and comprising the outer rim portion. The rim string conduit may be at least partially curved along its length. This may reduce any stress concentrations on the string.

The first and second hollow members may extend in the same general direction. For example, they may extend radially inwardly with respect to the racquet. The first and second hollow members may extend in substantially parallel directions. The first and second hollow members may be tubular.

The grommet may provide a grommet string conduit defining a substantially enclosed grommet string path between the open distal ends of the first and second hollow members. In such a case the grommet string path would include the rim string path.

The grommet may further comprise a damper provided on an outer side wall of the main grommet portion and arranged to be disposed between the main grommet portion and the frame. In use, this may allow the grommet to move with respect to the frame, thereby improving the performance of the racquet. The damper may extend around an outer side wall of the main grommet portion. For example, it may completely extend around the side wall. The damper may comprise an elastomer, such as rubber.

The profile of an outer surface of the main grommet portion may be configured to conform with the profile of the frame. For example, in use, the outer surface of the main grommet portion may be substantially flush with the outer surface or profile of the frame. This may improve the aerodynamic performance of the racquet.

The main grommet portion may comprise more than two hollow members. The outer rim portion may extend between the proximal ends of each of the hollow members. For example, if there are 20 hollow members, the outer rim portion, and if present an inner rim portion, may extend between all of the hollow members.

The invention also concerns a sports racquet, such as a tennis racquet, a badminton racquet, a squash racquet, or a racquetball racquet, comprising: a frame having a handle and a frame head that is arranged to be strung with at least one string; a first grommet opening extending through a portion of the frame head, a second grommet opening extending through a portion of the frame head, and a grommet recess formed in an outer surface of the frame head and extending between the first and second grommet openings; and a grommet in accordance with any statement herein, wherein the first and second hollow members are disposed within the first and second grommet openings, and wherein the outer rim portion is disposed within the grommet recess.

There may be a plurality of first grommet openings, a plurality of corresponding second grommet openings, and a grommet recess extending between each first and second corresponding grommet opening; and a plurality of grommets, each in accordance with any statement herein. An outer surface of the main grommet portion of the or each grommet may conform to the outer surface of the frame head. For example, the outer surface of the or each grommet may be flush with the outer surface of the frame head.

The racquet may further comprise a coating of resin and/or a coating of paint formed over the outer surface of the or each grommet and at least a portion of the frame head.

This may improve the aesthetic appearance and the aerodynamic performance of the racquet. The racquet may further comprise at least one string extending through the or each grommet such that the outer rim portion of the or each grommet covers the respective string.

According to another aspect of the invention there is provided a method of manufacturing a sports racquet, comprising: forming a frame having a handle and a frame head; forming a first grommet opening extending through a portion of the frame head, a second grommet opening extending through a portion of the frame head, and a grommet recess in an outer surface of the frame head and extending between the first and second grommet openings; and attaching a grommet in accordance with any statement herein to the frame head so that the first and second hollow members are disposed within the first and second grommet openings, and so that the outer rim portion is disposed within the grommet recess.

The method may further comprise forming a plurality of corresponding second grommet openings, and a grommet recess extending between each first and second corresponding grommet opening; and attaching a plurality of grommets, each in accordance with any statement herein, to the frame head.

The method may further comprise forming a coating of resin and/or a coating of paint over the outer surface of the or each grommet and at least a portion of the frame head.

The resin coating may be continuous and/or the paint coating may be continuous. The paint coating may be over the resin coating.

The method may further comprise stringing the frame head by passing a string through the or each grommet such that the outer rim portion of the or each grommet covers the respective string.

According to another aspect of the invention there is provided a grommet for a frame of a sports racquet, comprising: a main grommet portion comprising: first and second spaced hollow members that each have an open distal end; and an inner rim portion and an outer rim portion extending between the proximal ends of the first and second spaced hollow members, the inner and outer rim portions providing a rim string conduit defining a substantially enclosed rim string path.

The invention may comprise any combination of the features and/or limitations referred to herein, except combinations of such features as are mutually exclusive.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 schematically shows a previously considered sports racquet; Figure 2 schematically shows a cut-away view of a racquet frame showing a grommet according to an embodiment of the invention; Figure 3 schematically shows a cross-sectional view through the grommet of Figure 2; Figure 4 schematically shows a cross-sectional view through the grommet of Figure 3 with the cap removed; Figure 5 schematically shows an isometric view of the grommet of Figure 3 with the cap removed; and Figure 6 schematically shows the grommet of Figure 3 attached to a racquet.

Figure 1 shows a previously considered sports racquet in the form of a tennis racquet I comprising a frame having a handle 3 and a frame head 5. The frame head 5 is strung with racquet strings 7 comprising main strings 7a and cross strings 7b. As can be seen, the strings 7a, 7b are exposed on the outer rim 6 of the frame head 5. This may be aesthetically unappealing and may reduce the aerodynamic performance of the racquet 1.

Figure 2 shows a cut-away view through a portion of the frame head 5 of a sports racquet I incorporating a grommet 10 according to an embodiment of the invention. As can be seen, the frame head 5 is provided with a plurality of grommet openings 8 that extend through the entire thickness of the frame head 5. The openings 8 are substantially evenly spaced around the frame head 5 and extend generally in the radial direction. The frame head 5 further comprises a grommet recess 9 provided in the outer surface of the frame head 5 which substantially circumferentially extends between a pair of grommet openings 8. In this embodiment the grommet openings 8 are provided in pairs with a grommet recess 9 extending between the two openings.

However, in other embodiments there may be greater than two grommet openings with a grommet recess extending between them. The grommet 10 is disposed within the grommet openings 8 and grommet recess 9 and a racquet string 7 extends through the grommet 10. In this manner, the grommet 10 isolates the racquet string 7 from the frame 5 and therefore prevents the string 7 from coming into contact with the frame 5.

In this embodiment, each pair of grommet openings 8 is provided with a grommet 10.

However, in other embodiments a grommet 10 may be associated with greater than two openings.

With reference to Figure 3, the grommet 10 comprises a main grommet portion 12 having first and second hollowtubular members 14, 16. The hollow members 14,16 are spaced from one another in the lateral direction by a spacing corresponding to the spacing between adjacent grommet openings 8 provided in the frame head 5. The outer diameter of the tubular members 14, 16 have a diameter that is slightly less than the inner diameter of the grommet openings 8. The first and second hollow members 14, 16 are substantially parallel to each other and each have an open distal end 18, 20.

The main grommet portion 12 also comprises a hollow rim portion 22 that extends between the proximal ends 24,26 of the first and second hollow members 14, 16.

The hollow rim portion 22 comprises an outer rim portion 28 and an inner rim portion 30 that is radially inner of the outer rim portion 30. The outer and inner rim portions 28, 30 define a rim string conduit 32 therebetween which is connected to the hollow interiors of the first and second hollow members 14, 16. The rim string conduit 32 is curved along its length and provides an enclosed rim string path for a racquet string that is radially inwards of the outer rim portion 28. Therefore, a string extending along the rim string path is enclosed and is covered by the outer rim portion 28 on an outer side.

The main grommet portion 12 of the grommet 12 defines a continuous string conduit from the open distal end 18 of the first hollow member 14 to the open distal end 20 of the second hollow member 18. The rim string conduit 32 therefore forms part of the grommet string conduit. The grommet string conduit provides an enclosed grommet string path from the open distal end 18 of the first hollow member 14 to the open distal end 20 of the second hollow member 18.

The main grommet portion 12 comprises a flange 34 that is provided towards the top of the component. A damper 36 is provided that extends around the flange 34 that is made from an elastomer such as rubber. In use, the damper 36 is disposed between the main grommet portion 12 and the frame head 5 and allows the grommet 10 to move with respect to the frame head 5.

As can be seen from Figures 4 and 5, the inner rim portion 30 of the main grommet portion 12 is integrally formed with the first and second hollow members 14, 16 and forms a main body 38. The outer rim portion 28 forms is part of a separate cap 40 that can be detachably attached to the main body 38. The main body 38 is integrally formed from a plastics material by injection moulding. Similarly, the cap 40 is integrally formed from a plastics material by injection moulding. The cap 40 and main body 38 can be snap-fitted together. Although it has been described that the cap 40 can be detachably attached to the main body 38, in other embodiments, once the cap 40 has been attached to the main body, it may be difficult to remove it without damaging the grommet 10.

The grommet 10 may be incorporated into the racquet by at least two main methods.

Referring back to Figure 2, in one manufacturing method, the sports racquet frame is formed from a material such as carbon graphite. A plurality of grommet recesses 9 are formed around the outer rim of the frame head 5. The frame including the frame head is then coated with a layer of resin which is subsequently cured. The frame is then painted in order to improve its aesthetic appearance. A plurality of grommet openings 8 are then machined through the frame head 5, and in this embodiment a pair of grommet openings 8 are provided in each grommet recess 9. A main body 38 of a grommet 10, as described above, is then inserted into each grommet recess 9 so that the first hollow member 14 passes through one grommet opening 8, the second hollow member 16 passes through a second grommet opening 8, and the inner rim portion 30 is disposed within the grommet recess 9. In this arrangement the damper 36 is disposed between the main body 38 and the frame 5.

The racquet I is then strung by passing a string 7 through the open distal end 18, 20 of one of the hollow members 14, 16, over the inner rim portion 30 and out of the open distal end of the other hollow member 14, 16. After a string 7 has been fed through the main body 38 of each grommet 10, the cap 40 is located in place over the string 7. The cap 40, which provides the outer rim portion 28, completely covers the string passing across the grommet 10. As described above, the rim string path is radially inwards of the outer rim portion 28 50 that the string is completely covered. The outer surface of the grommet 10, and in particular the cap 40, is geometrically configured so that it is flush, and conforms with the general surface profile of the frame head 5. This results in a smooth outer surface profile of the frame head 5 which can reduce the drag of the racquet through the air. Further, since the strings 7 are covered by the caps 40 of the grommet 10, the aesthetic appearance of the racquet is improved. The caps 40 may also act to protect a portion of the strings 7.

If necessary, the racquet 1 can be restrung by either removing the caps 40, or by feeding the strings 7 through the grommets 10 with the caps 40 in place.

With reference to Figure 6, in an alternative manufacturing method, the grommets 10 with the caps 40 pre-attached the main bodies 38, are attached to the frame head 5 before the resin and paint layers are applied. After the grommets 10 have been inserted into the respective grommet openings 8 and recesses 9, a substantially continuous resin layer 42 is applied over the frame which covers the outer surface of caps 40 of each of the grommets 10. The resin layer 42 is then cured and is subsequently painted with a layer of paint 44 in order to give the appropriate aesthetic finish. Since the grommets 10 are completely covered on an outer surface with the resin 42 and the paint 44, they are not visible and do not protrude from the general surface level of the frame head 5. This therefore improves the aerodynamics and the aesthetics of the tennis racquet 1. If necessary, the racquet I can be restrung by feeding the strings 7 through the grommets 10 with the caps 40 in place as it is not possible to remove them.

Although it has been described that the frame head 5 of the racquet 1 is provided with a plurality of individual grommets, it should be appreciated that it would be possible to use a single grommet having an outer rim portion covering the outer surface of a portion of the racquet strings.

Claims

CLAIMS: 1. A grommet for a frame of a sports racquet, comprising: a main grommet portion comprising: first and second spaced hollow members that each have an open distal end; and an outer rim portion extending between the proximal ends of the first and second spaced hollow members; wherein the outer rim portion defines a rim string path between the proximal ends of the first and second hollow members that is radially inwards of the outer rim portion, so that in use a racquet string extending along the rim string path is covered by the outer rim portion.
2. A grommet according to claim 1, wherein the main grommet portion further comprises an inner rim portion, the outer and inner rim portions providing a rim string conduit defining a substantially enclosed rim string path.
3. A grommet according to claim 2, wherein the main grommet portion comprises a main body comprising the first and second hollow members and the inner rim portion, and a cap comprising the outer rim portion.
4. A grommet according to claim 3, wherein the main body and the cap are discrete components.
5. A grommet according to claim 4, wherein the main body and the cap are each integrally formed.
6. A grommet according to any of claims 3-5, wherein the cap is detachably attached to the main body.
7. A grommet according to any preceding claim, wherein the rim string path is defined by a hollow rim portion providing a rim string conduit and comprising the outer rim portion.
8. A grommet according to any of claims 2-7, wherein the rim string conduit is at least partially curved along its length.
9. A grommet according to any preceding claim, wherein the first and second hollow members extend in the same general direction.
10. A grommet according to any preceding claim, wherein the first and second hollow members extend in substantially parallel directions.
11. A grommet according to any preceding claim, wherein the first and second hollow members are tubular.
12. A grommet according to any preceding claim, wherein the grommet provides a grommet string conduit defining a substantially enclosed grommet string path between the open distal ends of the first and second hollow members.
13. A grommet according to any preceding claim, further comprising a damper provided on an outer side wall of the main grommet portion and arranged to be disposed between the main grommet portion and the frame.
14. A grommet according to claim 13, wherein the damper extends around an outer side wall of the main grommet portion.
15. A grommet according to claim 13 or 14, wherein the damper comprises an elastomer.
16. A grommet according to any preceding claim, wherein the profile of an outer surface of the main grommet portion is configured to conform with the profile of the frame.
17. A grommet according to any preceding claim, wherein the main grommet portion comprises more than two hollow members and wherein the outer rim portion extends between the proximal ends of each of the hollow members.
18. A sports racquet, comprising: a frame having a handle and a frame head that is arranged to be strung with at least one string; a first grommet opening extending through a portion of the frame head, a second grommet opening extending through a portion of the frame head, and a grommet recess formed in an outer surface of the frame head and extending between the first and second grommet openings; and a grommet in accordance with any preceding claim, wherein the first and second hollow members are disposed within the first and second grommet openings, and wherein the outer rim portion is disposed within the grommet recess.
19. A sports racquet according to claim 18, wherein there are a plurality of first grommet openings, a plurality of corresponding second grommet openings, and a grommet recess extending between each first and second corresponding grommet opening; and a plurality of grommets, each in accordance with any of claims 1-17.
20. A sports racquet according to claim 18 or 19, wherein an outer surface of the main grommet portion of the or each grommet conforms to the outer surface of the frame head.
21. A sports racquet according to any of claims 18-20, further comprising a coating of resin and/or a coating of paint formed over the outer surface of the or each grommet and at least a portion of the frame head.
22. A sports racquet according to any of claims 19-21, further comprising at least one string extending through the or each grommet such that the outer rim portion of the or each grommet covers the respective string.
23. A method of manufacturing a sports racquet, comprising: forming a frame having a handle and a frame head; forming a first grommet opening extending through a portion of the frame head, a second grommet opening extending through a portion of the frame head, and a grommet recess in an outer surface of the frame head and extending between the first and second grommet openings; and attaching a grommet in accordance with any of claims 1-17 to the frame head so that the first and second hollow members are disposed within the first and second grommet openings, and so that the outer rim portion is disposed within the grommet recess.
24. A method according to claim 23, further comprising forming a plurality of corresponding second grommet openings, and a grommet recess extending between each first and second corresponding grommet opening; and attaching a plurality of grommets, each in accordance with any of claims 1-17, to the frame head.
25. A method according to claim 23 or 24, further comprising: forming a coating of resin and/or a coating of paint over the outer surface of the or each grommet and at least a portion of the frame head.
26. A method according to any of claims 23-25, further comprising stringing the frame head by passing a string through the or each grommet such that the outer rim portion of the or each grommet covers the respective string.
27. A grommet or sports racquet substantially as described herein with reference to the accompanying drawings.