EP0317894A1

EP0317894A1 - Racket structure, particularly for tennis, squash or badminton rackets

Info

Publication number: EP0317894A1
Application number: EP88119102A
Authority: EP
Inventors: Giovanni Zago
Original assignee: TECHNORT Srl
Current assignee: TECHNORT Srl
Priority date: 1987-11-23
Filing date: 1988-11-17
Publication date: 1989-05-31
Also published as: IT8745754A0; WO1989004698A1; AU2789789A; JPH02502260A

Abstract

The racket structure has a head (1) having an extension (3), which is releasably coupleable with an interchangeable handgrip (5) through a coupling system (4,6,7,13-19). The coupling system (4,6,7,13-19) includes coupling ends defining appropriate seats (4,6) for inserting an expandable connecting element (7) so that the extension (3) and handgrip (5) thus coupled, once they are mutually tightened, become rigidly associated and correctly aligned. The connecting element (7) cooperates with elastic expandable connection members (13,15,17,19) which can also perform a shock-absorbing function between the handgrip (5) and the head (1) of the racket structure.

Description

The present invention relates to a racket structure particularly for tennis, squash or badminton rackets, which allows the user to modify its handgrip and/or handle as required.
As is known, a racket is often fully satisfactory in terms of its brand, quality, stringed area size (standard, mid-size or over-size) etc., but not equally satisfactory in terms of its handgrip.
The replacement of the handgrip currently entails the purchase of a complete new racket together with its stringing.
Even occasional or regular use on the part of relatives and friends entails the purchase of a new racket.
From a commercial point of view, the storage and management of various models furthermore entails the expenditure of capital with considerable risks of rapid obsolescence of the models involved.
These and other considerations may even affect the popularity of the sport.
The aim of the present invention is to provide a racket structure which does not have the above described disadvantages and has in particular an interchangeable handle and/or handgrip.
An object of the invention is to provide a racket structure wherein the handle and/or handgrip are easy, practical and convenient to fix and do not require particular tools or specialized personnel or the purchase of additional accessories.
A further object is to provide a racket structure wherein the coupling and fixing systems give the racket the same characteristics of rigidity and strength as conventional rackets.
Still another object is to provide a racket structure which, by virtue of the interchangeability of its handle or handgrip alone, can conveniently have a whole range of additional accessories provided, with a modest cost, in its replacement part.
A not least object is to provide a racket structure wherein the interchangeability of the handle and/or handgrip can impart different performance characteristics to the racket, which is thus easily and rapidly adapted to particular requirements of the game or the player.
This aim and these objects, as well as other objects which will become apparent hereinafter, are achieved by a racket structure for tennis, squash or badminton rackets, characterized in that it comprises a head, having a hollow extension, a hollow interchangeable handgrip, and a substantially cylindrical connecting body having ends adapted to be at least partially inserted inside said hollow interchangeable handgrip and said hollow extension, said substantially cylindrical connecting body having expandable means adapted for firmly interconnecting said hollow extension of said head, said hollow interchangeable handgrip, and said connecting body.
The expansion of said expandable means providing the connection conveniently occurs by turning a ring provided at the closed end of the handgrip.
Said expandable means are preferably constituted by elastic means adapted to provide a damped coupling between the handgrip and the racket frame, the damping or shock-absorbing effect thus obtained being adjustable according to the degree of tightening imparted thereto.
Further characteristics and advantages of the racket structure according to the invention will become apparent from the following detailed description of a preferred embodiment thereof, and from the accompanying illustrative, non-limitative drawing figures wherein:

figure 1 is a front elevational view of the racket structure according to the invention, in an assembled condition;
figure 2 is a fragmentary detailed cross-sectional view illustrating the handle portion of the racket structure;
figure 3 is a cross sectional view of the expandable means for coupling the handgrip and the head according to another aspect of the invention, and;
Figure 4 is a partially cut-away perspective view of a handgrip portion of the racket structure according to the invention, incorporating the expandable means of figure 3.

With reference to the drawing figures, the racket structure according to the invention comprises a frame or head 1, on which the strings 2 are tensioned with a conventional method. The frame 1 has an extension 3 internally provided with a cylindrical axial recess 4.
The racket further comprises a handgrip 5, which may have different shapes and dimensions according to the individual requirements of the tennis player. The handgrip 5, has an axial recess 6 having a cross-section substantially equal to the cross-section of the recess 4 of the extension 3, wherewith it is coupleable to provide the handle of the racket.
In order to firmly couple the extension 3 to the handgrip 5, a substantially cylindrical connecting body 7 is provided, comprising a central shaft 8 extending for the entire length of the cylindrical body 7, which is slightly shorter than the sum of the lengths of the two recesses 4 and 6.
The shaft 8 has a threaded portion 9 at the end 8a which is inserted into the recess 4, and a widened head 10 having a substantially prismatic axial recess 11 at the end 8b contained in the handgrip 5.
A first perforated and threaded substantially cylindrical element 12, a first expandable elastic sleeve 13, a second substantially cylindrical element 14, a second elastic sleeve 15, a third perforated substantially cylindrical element 16, a third elastic sleeve 17, a fourth perforated substantially cylindrical element 18, a fourth elastic sleeve 19 and a fifth perforated substantially cylindrical element 20 are inserted onto the shaft 8 and are arranged in an alternate manner as illustrated in figure 2.
The first two expandable sleeves 13 and 15 are, in an idle condition, slightly smaller than the recess 4 in which they are contained.
Similarly, the sleeves 17 and 19 are, in an idle condition, slightly smaller than the recess 6 in which they are contained.
After assembly, which is effected by inserting the cylindrical connecting body 7 into the two recesses 4 and 6 and by moving the handgrip 5 into contact with the extension 3, the threaded portion 9 screws onto the first perforated and threaded cylindrical element 12 by turning the shaft 8, thus shortening the entire cylindrical body and causing axial compression of the elastic sleeves 13, 15, 17 and 19 which expand and firmly frictionally engage, and thus adhere to the inner walls of the recess 4 and the recess 6 respectively. The friction generated by the expandable sleeves produces a safe and firm coupling between the handgrip 5 and the extension 3 of the frame 1. The firmness of the coupling can be adjusted by screwing the shaft 8 more or less tightly and thus expanding the elastic sleeves to a greater or smaller extent. The elasticity of the coupling furthermore provides an adjustable shock-absorbing effect between the frame and the handle, this being an important factor in preventing tendon inflammations for players who devote many hours to sport and in general for whoever has weak forearm musculature.
In order to rotate the shaft 8, the end of the handgrip is expediently constituted by a freely rotatable cylindrical segment 20 which cannot be separated from the handgrip 5.
The segment 20 is axially provided with a prismatic hole 21 which contains a complementarily shaped protruding prismatic body 22 the end whereof enters the prismatic recess 11 of the head 10 of the shaft 8.
Figure 2 illustrates a condition of incomplete assembly, in which the prismatic body 22 is not yet inserted into the recess 11.
The prismatic body 22 can move elastically within the segment 20 so that even if their positions do not coincide during assembly the insertion of the prismatic body 22 into the recess 11 occurs at the beginning of the rotation of the segment 20; the coupling is therefore tightened or slackened by acting on said segment 20.
Any number of expandable sleeves may be provided, providing that at least one sleeve of adequate length is contained in the recess of the extension of the frame and at least one is contained in the handgrip.
Obviously, the elements of the inventive racket structure may be substituted by technically equivalent elements, without thereby departing from the purview of the instant inventive concept.
For example, alternately to a shaft which expands the sleeves by rotation, a shaft 23 can be provided, tensioned by means of a lever 24 (see figures 3 and 4) pivoted on the shaft and provided with a cam 25.
The lever is shaped so as to enter the handgrip 26, its rotation through approximately 90° causing the partial extraction of the shaft 23 and the expansion of the expandable sleeves 27.
At its other end, the shaft 23 is screwed onto a first threaded cylindrical body so as to preadjust the compression of the sleeves 27.
The lever 24 can be accessed through an opening 28 provided in the handgrip 26.
The operation of the expandable means illustrated in figures 3 and 4 is exactly the same as the operation of the expandable means of figures 1 and 2, described heretofore.
A racket thus configured allows to combine a large variety of frames with an equally large variety of handgrips without requiring tools or specialized personnel.
The intended aim and objects are thus achieved.
Obviously, any materials and dimensions may be used according to requirements.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

1. Racket structure, particularly for tennis, squash or badminton rackets, characterized in that it comprises a head, having a hollow extension, a hollow interchangeable handgrip, and a substantially cylindrical connecting body having ends adapted to be at least partially inserted inside said hollow interchangeable handgrip and said hollow extension, said substantially cylindrical connecting body having expandable means adapted for firmly interconnecting said hollow extension of said head, said hollow interchangeable handgrip, and said connecting body.

2. Racket according to claim 1, characterized in that the cylindrical body is composed of a central shaft which has a threaded region on one side and a widened head on the other, hollow cylindrical bodies and expandable elastic sleeves being alternately inserted on said shaft.

3. Racket according to claim 1, characterized in that the first cylindrical body is threaded and screws onto said shaft on the side opposite to the head thereof, causing compression of the elastic materials and their expansion after inserting the cylindrical body in the recesses of the frame extension and the handgrip.

4. Racket according to claim 1, characterized in that at least one elastic sleeve is contained in the extension of the frame and at least one elastic sleeve is contained in the handgrip.

5. Racket according to claim 1, characterized in that the shaft is rotated by acting on a rotatable segment of the handgrip having means associated with the head of the shaft of the cylindrical body during assembly.

6. Racket according to claim 1, characterized in that the shortening of the elements which expand the elastic sleeves can be obtained, by pulling the shaft with a lever pivoted on the end of said shaft on the side of the handgrip and having a cam which interacts with the first cylindrical element and pushes it towards the others.

7. Racket according to claim 1, characterized in that the elastic sleeves in the coupling constitute damping means which is adjustable by adjusting the compression of said sleeves or the type of material used.