GB2253793A

GB2253793A - A racquet

Info

Publication number: GB2253793A
Application number: GB9109573A
Authority: GB
Inventors: Carlo Zaccaro
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-01-07
Filing date: 1991-05-02
Publication date: 1992-09-23
Also published as: ITRM910005A0; IT1244637B; GB9109573D0; ITRM910005A1

Abstract

A tennis racquet 1 having advantageous shock absorbency characteristics consists of a frame 2 which supports an open network of strings 3, the frame 2 comprising a substantially stiff support member 11 and an inflatable member 12 which is variably inflatable by means of a valve 18. The network of strings 3 is supported from the frame so as to define two outwardly-facing playing surfaces which are each generally concave, the network 3 comprising a substantially planar central portion 13 and surrounding peripheral portions 14 inclined thereto. The string elements 4 of the network have nodular portions 15 and are preferably multifilamentary. <IMAGE>

Description

A RACOUET The invention relates to a racquet for a ball game and particularly, but not exclusively, to a tennis racquet.

Tennis racquets presently consist of a frame, a handle extending from the frame, and an open network of strings stretched on the frame, the string network comprising two groups of string members, the plural string members of each group extending between opposed sides of the frame, substantially parallel to each other and substantially perpendicular to the plural string members of the other group, such that the network defined by the string members is substantially flat and planar.

Such conventional tennis racquets suffer from the disadvantage that if a tennis ball is struck with a peripheral part of the string network adjoining the frame the direction of travel of the ball subsequently to being struck is uncertain and it is difficult to control the angle of impact and rebound of the ball.

This disadvantage is particularly noticeable, for example, when striking a ball very near to the ground or well above the head height of the player.

The invention seeks to overcome this disadvantage in that it provides a racquet for a ball game, said racquet comprising a frame supporting an open network of strings defining two oppositely facing playing surfaces, and said strings being supported by the frame so that the playing surfaces are each generally concave.

In a preferred embodiment of the invention which will be described in detail hereinafter, the network of strings comprises a substantially planar central portion and a surrounding peripheral portion, the strings being supported from the frame at two sets of locations which are spaced apart from each other in the direction perpendicular to the plane of said central portion, and the peripheral portion being defined by the string sections extending from respective ones of said two sets of locations towards the central portion. By virtue of this arrangement the peripheral portion of each playing surface is inclined at an angle to the planar central portion and this provides the respective playing surfaces with a generally concave shape.This arrangement contrasts with that of a conventional racquet where the strings are supported from the frame at but a single set of locations all in the same plane thereby defining a flat playing surface.

At least some of the strings preferably have a plurality of substantially spherical and substantially uniformly spaced nodulous portions located along at least a portion thereof. These nodules, which may be defined by knots in the strings or may be attachments to or integral with the strings, enhance the frictional contact between the racquet and a ball being struck and are advantageous for example where it is desired to impart spin to the ball.

The frame may advantageously have adjustable elasticity for enabling string tension and/or the shock absorbency of the racquet to be adjusted to suit the particular requirements of a user. Thus in an embodiment described in detail hereinafter, the frame has an inflatable portion extending around a supporting frame member which locates and supports the string network, and the strings extend around the inflatable portion so as to be tensioned thereby in dependence upon the degree of inflation thereof and additionally so that the inflatable portion acts as a shock absorber to limit transmission through the handle of the racquet to the arm of the user of impact forces developed by the ball striking the strings. By minimising the effect of such impact forces on the user, sports injuries and other disabling conditions can be avoided or at least minimised.

In accordance with a further aspect the invention also provides a racquet for a ball game, said racquet comprising a frame supporting an open network comprising a plurality of string elements, each said string element being formed by a plurality of strands.

The invention also provides a racquet for a ball game, said racquet comprising a frame supporting an open network of strings and having a handle extending therefrom, said frame comprising a substantially stiff frame member defining support locations for said strings and an inflatable frame member engaging said substantially stiff frame member, said inflatable frame member comprising valve means for enabling adjustable inflation thereof and the degree of inflation being arranged to determine the tension in the string.

The above and further features of the invention are set forth with particularity in the appended claims and together with advantages thereof will become clearer from consideration of the following detailed description of exemplary embodiments of the invention given with reference to the accompanying drawings.

In the drawings: Figure 1 shows a plan view of a first embodiment of a racquet according to the invention; Figure 2 shows a cross-sectional view taken along the line II-II in Figure 1; Figure 3 shows a partial side view of a second embodiment of a racquet; and Figure 4 shows a sectional view along the line A A in Figure 3.

Referring to Figure 1, there is shown a racquet 1, which in the case of the present embodiment is a tennis racquet. The racquet 1 comprises a frame 2 which supports an open network 3 comprising a plurality of string elements 4, and the two outwardly facing playing surfaces defined by the network 3 are each generally concave as can be seen from Figure 2.

In the racquet 1 shown in Figure 1, the frame 2 defines a generally oval shape, and a handle 5 extends from the frame 2 and is terminated by a grip 6 which is covered with a material such as to resist slipping of the grip 6 in a player's hand.

The string elements 4 of the network 3 are arranged in two orthogonal groups, the plural string elements of each group extending generally parallel to each other and generally perpendicular to the plural string elements of the other group. The string elements 4 of the network 3 are all formed as parts of a single continuous length of string material which is strung through holes 7 in the frame portion 2, the length of string material being passed through holes 7 provided in the frame 2 and extending around the external periphery of the frame as explained more particularly hereafter.

As shown in Figure 2, the network 3 defines two playing surfaces each of which comprises a planar central portion 13 and a surrounding peripheral portion 14 which extends at an angle to the central portion and has a considerably smaller surface area than the central portion 13. The central portion 13 and the peripheral portions 14 are formed by virtue of there being two distinct sets of string support holes 7 provided in the frame, the two sets of holes being provided at locations which are spaced apart from each other in a direction transverse to the general plane of the racquet. By looping the strings around the frame with the strings threaded alternately through respective ones of the two sets of support holes and by interweaving the two orthogonal groups of strings the provision of peripheral portions 14 inclined to the central portion is assured.

Referring in more detail to Figure 2, the frame 2 comprises a substantially stiff support member 11 and an inflatable member 12 extending in engagement therewith around the outer periphery thereof; the construction and function of the inflatable member will be described in detail below. The string support holes 7 are provided in the support member 11 and as shown are offset from the plane 10 on opposite sides thereof, and the string material forming the string elements 4 extends across the face of the racquet, passes through a hole 7 through the support member 11, one of the lower set of holes say, then passes around the external periphery of the inflatable frame member 12, and passes through the next support hole of the upper set of holes and back across the face of the racquet where it forms a further string element 4'.

In this way the string repeatedly crosses the face of the racquet and engages the stiff support member 11 by passing through the holes 7,7' and around the inflatable member 12, first in one direction and then in the orthogonal direction so as to define two orthogonal groups of string elements. The two orthogonal groups of string elements are interwoven so that points 9 of intersection of each group of string elements with respective string elements of the other group are defined around the periphery of the planar central portion of the string network and the string elements extend outwardly from these points 9 in divergent directions to define the inclined peripheral portions of the string network.

As mentioned above, the frame 2 comprises a substantially stiff support member 11 and an inflatable member 12 which engages the support member 11 around its outer periphery. The frame 2 is provided with apertures 16 which allow the inflatable frame member 12 to pass through the yoke defined by the joining of the handle to the frame, and a valve 18 is provided for enabling the inflatable member 12 to be adjustably inflated, the valve 18 preferably being of a type similar to that used for bicycle tyres for example, though any suitable valve may be used. The support member 11 has a cross-section generally in the shape of an arc of a circle, and is constructed of a Kevlar and Pirite mixture for example, and the inflatable member 12 is a circular cross-section tube 19 formed for example of reinforcing nylon filaments within a sleeve 20 of silicone rubber.

As shown in Figures 1 and 2, each string element 4 has a plurality of spherically-shaped nodular portions 15 whose diameter in the present embodiment, is approximately 4/3 times that of the string element 4 at a location free of nodular portions 15. These nodular portions 15 have fairly uniform spacing from each other along at least a portion of the string element 4 and serve to dampen waves of vibration in the net portion 3 caused by the racquet 1 striking a ball, as well as to increase the friction between a ball and the strung portion 3 so as to augment any spinning motion imparted to a ball on striking. In this embodiment, the spacing of the nodular portions 15 is generally 3/8 inch (0.9 cm).The nodular portions may be integral with the strings, for example by virtue of being moulded in situ, or may be formed as separate elements attached to the strings or even as knots in the strings.

The above-described embodiment of the present invention has the advantage that the generally concave playing surfaces facilitates determination of the direction in which a ball is struck, particularly for a non-expert player. Furthermore, the advantageous effect achieved by the invention is generally most noticeable for tennis players of not very high standard, since players of very high standard tend invariably to strike the ball with the central portion of the string network 3.

As is well known, problems such as tennis elbow and other injuries or conditions may be caused or aggravated by vibrations transmitted through the handle of the racquet to the arm of the player. The described embodiment alleviates such problems since vibrations in the net portion 3 caused by a ball striking the racquet are substantially absorbed by the inflatable member 12 before they can be transferred to the handle 5 of the racquet 1. In addition, by varying the degree of inflation of the inflatable member 12, the flexibility and shock absorption ability of the frame 2 of the racquet 1 as a whole can be varied.

Finally, by forming the string elements 4 from several strands, as is preferred, the advantage is obtained that if one or more, but not all, of the strands of a string element 4 breaks, then frayed parts of the string element 4 may be seen and so some advance warning is given before a string element 4 breaks completely.

It is to be appreciated that the above-described embodiment is given by way of example only, and that the invention is not intended to be limited to this embodiment. For example, while the string elements 4 can conveniently be formed of plastics material, they need not be and any other suitable material may be used. Thus the string elements 4 could for example be formed of a natural fibre material such as jute, in which case if nodular portions 15 are to be provided they could be formed by tying knots in the string material. Alternatively the nodular portions 15 need not be provided, and furthermore the string elements 4 need not be formed from several strands.

Further, the frame 2 need not comprise a substantially stiff support member 11 coupled with an inflatable member 12, but rather could for example be formed of hollow tubular material such as Perspex which could be reinforced by a lightweight metal sleeve. In the event that the frame 2 does comprise a substantially stiff support member 11 and an inflatable member 12, the member 11 could be formed of any suitable material such as aluminium, in particular in the form known as Erg-Alu (Trade Mark). The inflatable member 12 could be formed of a canvas material vulcanised with rubber, or any other material having suitable properties.The inflatable frame member 12 need not be exposed at the yoke 17 of the racquet but rather could extend along the inside of the handle 5, in which case it could advantageously be inflatable by means of the valve 18 being located in a recess in the grip 6 for example. Alternatively the frame 2 could be so arranged that the substantially stiff support member 11 has an inner periphery engagable by the inflatable frame member 12, in which case inflation of the inflatable frame member 12 could serve to increase tension in the net portion 3 of the racquet 1.

In addition, the apertures 16 of the present embodiment could, instead of being in the form of holes, be in the form of open slits, slots or open apertures to allow removal and replacement of the inflatable frame member 12 if this component should become worn or be damaged.

The cross-sectional shape of the substantially stiff frame member 11, instead of having the shape of an arc of a circle, may be U-shaped, V-shaped, Cshaped or any other suitable shape.

It will be appreciated that the substantially stiff frame member 11 is not completely stiff and will inevitably and desirably have some elasticity.

An alternative frame arrangement is shown in Figures 3 and 4 of the accompanying drawings. Figure 3 shows a side view of a portion of a frame 30 as viewed in the direction of arrow B in Figure 4. and Figure 4 is a section view along A-A in Figure 3. As can be seen from Figures 3 and 4, plural apertures 31 are formed along an outward facing surface portion of the frame 30 at an angle inclined to the axis of the frame and complementing plural apertures 32 are formed along an inward facing surface portion of the frame.

The frame 30 is of substantially elliptical section and contains an inflatable member 33 around which is passed a string element 34. The string element 34 passes through a lower end portion of one inner aperture 32a, around the inflatable member 33 following the line of the respective outer aperture 31, and back out through an upper end portion of another inner aperture 32b. In this way, the string element passes through the frame 30 and is supported by the inflatable member 33. The string element 34 may be weaved as described above in respect of Figures 1 and 2 of the drawings to form a string network having the same or similar properties and characteristics.

Having thus described the present invention by reference to preferred embodiments it is to be well understood that the embodiments in question are exemplary only and that modifications and variations such as will occur to those possessed of appropriate knowledge and skills may be made without departure from the spirit and scope of the invention as set forth in the appended claims and equivalents thereof.

Claims

CLAIMS:

1. A racquet for a ball game, said racquet comprising a frame supporting an open network of strings defining two oppositely facing playing surfaces, and said strings being supported by the frame so that the playing surfaces are each generally concave.

2. A racquet according to claim 1, wherein said network comprises a plurality of strings forming two groups, the plural strings of each group extending substantially parallel to each other and transverse to the plural strings of the other group.

3. A racquet according to claim 1 or 2, wherein each said playing surface comprises a substantially planar central portion and a surrounding peripheral portion.

4. A racquet according to claim 3, wherein the strings are supported from the frame at two sets of locations which are spaced apart from each other in the direction transverse to the plane of said central portion, and the peripheral portions of the playing surfaces are defined by the string sections extending from respective ones of said two sets of locations towards the central portion.

5. A racquet according to any of the preceding claims, wherein said strings are multifilamentary.

6. A racquet according to any of the preceding claims, wherein at least some of said strings have a plurality of substantially spherical and substantially uniformly spaced nodulous portions located along at least a portion thereof.

7. A racquet according to any of the preceding claims, wherein said frame is adjustable for adjusting the tension of said strings and/or providing shock absorbency for the strings.

8. A racquet according to claim 7, wherein said frame comprises an inflatable frame portion arranged such that the degree of inflation thereof determines the tension of the strings and/or the degree of shock absorbency therefor.

9. A racquet according to claim 8, wherein the frame comprises a support member defining support locations for the strings and said inflatable frame portion comprises a tubular member extending around the outer periphery of said support member, and the strings extend around said tubular member.

10. A racquet according to claim 9, wherein said support member is constructed to permit replacement of said inflatable frame portion.

11. A racquet for a ball game, said racquet comprising a frame supporting an open network comprising a plurality of string elements, each said string element being formed by a plurality of strands.

12. A racquet for a ball game, said racquet comprising a frame supporting an open network of strings and having a handle extending therefrom, said frame comprising a substantially stiff frame member defining support locations for said strings and an inflatable frame member engaging said substantially stiff frame member, said inflatable frame member comprising valve means for enabling adjustable inflation thereof and the degree of inflation being arranged to determine the tension in the string.

13. A racquet substantially as hereinbefore described with reference to the accompanying drawings.