CA1219295A - Racquet with improved string anchorage - Google Patents

Abstract

RACQUET WITH IMPROVED STRING ANCHORAGE

ABSTRACT
A racquet has a sinuous string-securing member anchored in a groove around the internal periphery of the racquet frame. An anchoring member, which is wider than the mouth of the groove, engages each mounting portion of the string-securing member, and is trapped in the groove behind the mouth. The anchoring members may be made of nylon, and may be snap-fit over the mounting portions prior to sliding the entire string-securing assembly into the groove.

Description

2~i RACQUET WITH IMPROVED STRING ANCHORAGE

BACK~P~OUND OF THE IP~VEi NTION
This invention relates to racquets.
A typical racquet comprises an ~pproximately oval frame, usual~y of wood or extruded aluminum) having ~ plur~lity of holes extending substantially radially therethrough, the stringing of the racquet being directly secured to the frame by p~ssing individual strings thereo~
through the holesO Typically, a given string is pas ed outwardly through a respective hole in the îr~me and thea inwsrdly through an adjacent hole.
HoweveP, ~uch a rscquee suf~ers ~rom a number of dis~dYantages.
For example, parts Or the stringing are at least partly exposed at the radially outer surace Or the fsame (i.e., between Qdjacent holes in the frame)~ and ~re thus subject to d~mage ~s ~ result o~ impacts, e.g., wieh the groundO Also, the strings tend to fret a~inst the frQme, especially where they psss over the edges of the radially outer ends of the holes in the ~rame, this ~retting eventually leading to breakage OI
the strings. Additionally, msnuga~turing costs sre ineredsed by the necessity for drilling snd deburrir.g the holes, and providing snd ~Itting grommets in the holes, all of which oper~tions can be labor intensive.
Most signif~antly, the holes in the frame tend to ~et up stress con centrstions so thst when the ~r~me is severely stressed, lt almost invariably breaks in the region Or ~ hole.

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It has already been proposed, in my United Kingdcn Published Patent Application (Publication No. 2,094,643, published on September 22, 1982), to alleviate the abovementioned disadvsntsges by pro~iding a rscquet In whlch the ~rame h~s a groove extending around the greQter part o~ ~t~ Intern~l periphery. The strlnging of this r~cquet Is secured to the frame by mesns of a one-piece sinuou3 string~ecuring member msde rrom a suit~bly bent lenggh of wire. This member is held in the groo~re by making the width of the portions of the wlre disposed in the groo~re exceed the width Or th~ mouth o~ the groove by deforming them o~ by crimping the mouth of the groo~re.
This propossl, ~Ithough it does indeed ~lleriate the aforementioned disadYsntages and proYides ex~llent rE~cquets, nevertheless sutfers from 8 number of production drawbacks. In p~r-ti~ui~r, the de~orming ~nd ~rimping steps ~an be r~ther time consuming, ~nd holding the wire string-seollring member in the groove during the crimping operation presents ~aome diffi~ulty. Additionally, the frBme~ of racquets in accord~nce with the propcssl ~re usuellly msde from extruded aluminum, often with highly decor~ti~e finishes ~hieh ~re produ~ or ex~mple~ by Anodizin~. These rInishes c~n be adYersely affected by the crimping operatlon, while the s~eual deSorm~-tion produced by the crimping operation ~n of ~tsel~ detr~clt somewhst from the plea~ing ~esth2tic ~ppearance of the racquetO
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lt is therefore an object of the pre~ent invention to provide racquet which ret~in~ the princip~l ~dv~ntages of my prior proposal~
while neverth~less alleviating ~ts production drswb~
A~cording to the present in~ention, there is provided ~ r~quet compri~ing ~ ~trin~-support~ng îr~me having a groo-/e extending ~round the gre~ter p~rt of the ~ntern~l periphery thereof, the mouth of the groove being r~rrower than the b~se of the grooYe~ The stringing is ,,~ ' ,~"." . ;t - - . :-.: , ,. ..
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secured to $he ~r~me by a sinuous string seeuring member bent to define a plur~lity of ~Iternate mounting portions and inYI~rdly projec-ting string securing loops. The mounting portions are held in the groove by anchoring members each ~Ying a ~hannel f~cing the ~ase of the groove in which a mount ing portion i~ ret~ined. The anchoring members are wider than the mouth of the grooYe ~v us to be trapped in the groove behind the mouth.
In a preferred embodiment of the invention, the side walls of the groove converge towards the mouth thereo~, and the sides of the anchoring members are shsped to be complementary to the side walls of the groove. Preferably, the cross-sectionfll sh~pe of the anchoring members is complernentary to the cross-se~tion~l shape of the groove.
It is further pre~erred th~t the mouth of the groove be defined by lips which project toward each other from the side wAlls.
Advantageously, the ~nchoring members ~re made from nylon, and the channels therein are sh~ped to be ~ snap-fit over more than half the circumference of the mounting portions. Additionally, the length of each anchoring member~ in the direction of the groove, is preferably substantially equal to the length of the mounting portion which it engages BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example only, with reference to the accomp~nying drawings, of which:
Figure 1 is a front eleYational vle~ of a badminton racquet in flccord~noe with the present inYenffon;
Figures 2 and 3 ~re enlarged front and side elevstion~l views, respectively, of a joining or securing member ~or securing the handle o~ the racquet of ~igure 1 to the rame; ~nd Figure 4 is an enlarged sectional view taken along line ~ in Figure 1.

DESC RIPTIO P~
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The badminton ra~quet of Figure 1 ls indlcated gener~lly at 10, Qnd comprises e generally toroid21 fr~me la which is ~lightly oval in sh~pe ~nd m~de from a ~ingle le;lgth of e~ctruded alumirlum tubing 14 bent, e.g., ~round ~ ~ormer, to produ¢e the oYal ~hape of the frame.
The opposite end~ 16, 18 of tublng 14 ~but ea~h cther, and Are welded or otherwlse bonded together, e.g., with 3uitabl~ ~dhe3iYe.
A slim tubulAr ~t~el handle ao extend3 ~ubst~ntially rsdially of frame 1~ Lnd carri~s ~t the end r~mote from the itrAme a hand-grip (not shown~ of ~ood or pl~sti~. The h~ndle 20 ~ typi~ally o~ ~ircul~r cross-section, and its diameter may either b~ uniform or incre~se slightly with increasing dist~nce ~rom frame 12.
The handle 20 is secured to frame 12 by means of an aluminum member 24, which is shown ill more dlet811 in F~gure~ 2 and 3. The member 2~ comprises ~irst and ~econd integr~lly ~ormed tubular por-tions 26 and as, of which the lAtter extends perpendi~ul~rly ro m the middle ot the former. The ~irst tubular portion 2~ is sh~ped to receive ~nd tightly fit around the bond~d-together ends 1~;9 lE~ of tubing 1~ o~ the frsme, ~hile the second tubulRr portaon 28 e~tends subst~ntially radially of ~8Jlle 12 and Is shaped to recei~re and tightly ~t arou;ld the other end of hAndl~ 20. The ends 16, 18 ~nd the other end o[ h~ndle ao are bonded within the portion~ 26, 28 respectively9 e.g~, with the ~orementioned adhesi~re.
~ n an altern~tive eonstruct~on (not shown)9 h~ndle 20 is secure to frame la by me~ns o~ a V-sh~ped member~ ~ubstantiaîly as described in U.K. ~lication 2,094,643.

The tubin~ 14 of tr~me la is Yhown In ~ection in lFigure g, from which it c~n be seen th~t the tub~ng is o~ ~ub3t~nti~11y o~al section7 Witll the m~jor axi$ o~ the oval ~h~pe extending perpendicu-larly to the plane Or the frame. The wall thiekness of tubing 14 is typically of the order of 1 mm, except for the thicker portion 30 ,,.~' ~q~r-~

which constitutes the ~ntern~l periphery of ~rame la Yvhen tbe tubing is bent AS described earlier is sh~ped to define a groove 3a.
The s5de ~Alls 34 of grooYe 32 eonverge symmetrically towards the mouth 36 Or the groove, which is de~ined between lips 37 which project towards each other from the s~de w~lls 34. The width of mouth 36 of groove 32 is typically very sligh~ly in excess of 1 m m .
GrooYe 32 serves to hold a ~ne-piece wire str~ng-securing member 38, which is tr~pped in groove 3a bene~th ~ plurality of wedge-shaped nylon ~nchorjng members 50.
As c~n be seen in ~igure 1, string-securing member 38 comprises a single length of steel wir~ bent into a sinllous shap~ resembling castellations or crenell~tions in side view, ~nd de~lning a plur~lity of U-shaped string securing loops 40~ of which adjacent ones are integrally joined together ~t the tops of the limbs of their IJ-shapes by mounting or connecting portions 42. The di~meter of the ~ire msking up member 38 is typic~lly 1 mm, i~e., just 10ss th~n the width of mouth 36 OI groove 3a (Figure 4~.
As alresdy mentioned, the string-securing member 38 is held in groove 32 by a plurality oî snchoring members Sû ~Figure ~.) The cross-section~l wedge shape of each ~nchoring member 50 is subst~ntially complementnry to the cross-seGtior3al sh~pe of groove 32, so the members 50 c~n be slid into groove 32 fi~om one OI the ends 16, 18 of the tubing 14 before these ends ~re bonded to~ether.
Members Sû $hus have two ~ide faces sa which engage the side w~lls 34 of the groove 32, ~ base 54 which f~ce~ the base of the groove, Qnd a top surface 56 whicb ~ces out of mouth 36 of the groove ~nd whose ~dges Qre trapped bene~th the lips 37.
The center Or b~se 54 Or each ~nchoring member 50 h~s a channel 58 formed therein, the channel extending perpendiculariy to the plsne of Figure 4. The ch~nnel 58 hss a p~rt-circul~r cross-section, and is shaped and dimensioned to tightly embrace about three quarters of the circum~erence ot the wire o~ the mollnting portions 42 of ~he string~ecuring member 38.

To make up r~cquet 10, an ~nchoring 50 is ~lipped cr snapped oYer each mounting portion 42 of string-securing membeP 3~ the resil-ience o~ the nylon permitting this snsp ~it. It ~ill be ~ppreciated thQt, once snapped into position, members 50 t2nd to grip onto the mounting portions 42. The length of e~ch ~nchoring member 50 is chosen to be iust less than or egual to the length of the mounting portion 42 onto whieh it is fitted.
Then, prior to bonding together the ends 16, 18 of bent tu~ing 14 making up fr~me 129 anchoring members 50, still mounted on string-securing member 38, ~re slid together with the mounting portions 42 of memb~r 33 into grooYe 329 the string securing loops 40 of member 38 being ~ligned with mouth 36 of the groove to permit this.
This continues until the member 38 extend3 around substantially the whole of the internal periphery of the ~r~me (ex~ept ~or the portions of the fr~me which fit within ghe tubul~r portion 2B of ~luminum member 24). End portions 16, 18 of tubing 14 ~re then bonded together withln portion 26 of aluminum mernber 24, at which point member 38 is ~lrmly h~l~ in groove 32 by ~rirtue of the entrApment of mounting portions 42 thereof beneath ~nchoring rnembers 50, and string securing loops 40 project rRdi~lly into frame 12 thro-lgh mouth 36 OI
the groove, and of course lie ~n the plane of the frame~ as shown in Figure 1. The racquelt 10 then c~n ~e strung wlth stringing 4~ by pQSsing the stringing through loops 40, also ~s shown in Figure 1.
The widths o~ the respective string securing loops 40 are IlOt 811 the same, but sre selected ~uch that the desired~ e.g., uniform, string spacing is ~chieved. As can be seen in Figures 1 to 3, a single stringing loop 46 is formed integrally with aluminum member 249 pro-jecting radi~lly into ~rame la from portion 26.
It will be appreci~ted that because the stringing of the racquet is supported on the wire string~ecuring member 38, which is in turn held in groove 329 it i~ no longer necessary to drill holes in tubing 14 of frame 12. This eliminates the form~tion of the - .. - ~ ..

_ 7 _ stress-concentrations normally ~ssoci~ted with such holes, and ensbles the production of a lighter ~nd/or stronger ~r~me.
It will further be appreciAted tha t, by erirtue of the use of nylon anchoring members 50, there is no need to de~orm mounting por-tions 42 of ~ire strjng-securing member 38 in order to widen l:hem, nor, more importantly, any need to erimp mouth 36 of groove 32.
The use of nylon, which l~s a low eoefficient of friction, for mernbers 50 eases assembly by ensuring that they slide easily irlto grooYe 32.
Assembly also is simplified by the fact that members 50 clip onto and grip the wire of string-securins member 38. The possibility of wire string-securing msmber 38 pulling out of groove 32 is virtually elim-inated, especially since the wedge shape ot anchol inK members SO
cooperates with side walls 34 of groove 32 to ensure that members 50 grip the wire of member 38 more tightly in response to movement of members 50 towards the mouth 36 of the groove.
It will be obvious to those skilled in the ~rt that ~rari~tions of the abov~described preferred embodiment may be made within the scope of the invention, which is defined by the appended elaims.

Claims (17)

1. A racquet comprising:
a string-supporting frame having a groove extending around the greater part of the internal periphery thereof, the mouth of the groove being narrower than the base of the groove;
a sinuous string-securing member having a plurality of spaced mounting portions anchored in the groove and a plurality of spaced string-securing loops projecting inwardly toward the center of the racquet from the mouth of the groove; and a plurality of anchoring members in said groove which are wider than said mouth so as to be trapped within said groove behind said mouth, each of said anchoring members having a channel facing the base of said groove and retaining a respective one of said mounting portions in said channel.

2. A racquet according to claim 1 wherein said channel is dimensioned to fit closely with said mounting portion.

3. A racquet according to claim 2 wherein said channel closely surrounds more than half the perimeter of said mounting por-tion so that said anchoring member can be snap-fit over said mounting portion.

4. A racquet according to claim 3 wherein the length of each of said anchoring members, in the direction of the groove, is substantially equal to the length of its respective mounting portion.

5. A racquet according to claim a wherein said anchoring members are plastic.

6. A racquet according to claim 5 wherein said anchoring members are nylon,

7. A racquet according to claim a wherein the cross-sectional shape of the anchoring members is complementary to the cross-sectional shape of the groove.

8. A racquet according to claim 7 wherein said groove and said anchoring members are wedge-shaped in cross-section, the cross-section tapering toward the mouth of said groove so that tension on the strings tends to wedge said anchoring members more tightly in said groove.

9. A racquet according to claim 8 wherein said anchoring members are resilient, whereby said mounting portions are more tightly retained in said channels when said anchoring members are more tightly wedged in said groove.

10. A racquet according to claim 9 wherein said channel closely surrounds more than half the perimeter of said mounting por-tion so that said anchoring members can be snap-fit over said mounting portions.

11. A racquet according to claim 10 wherein the length of each of said anchoring members, in the direction of the groove, is substantially equal to the length of its respective mounting portion.

12. A racquet according to claim 9 wherein said anchoring members are plastic.

13. A racquet according to claim 12 wherein said anchoring members are nylon.

14. A racquet according to claim 8 wherein said mouth is defined by opposed lips extending from the tapered sides of said groove.

15. A racquet according to claim 1 wherein the cross-sectional shape of the anchoring members is complementary to the cross-sectional shape of the groove.

16. A racquet according to claim 15 wherein said groove and said anchoring members are wedge-shaped in cross-section, the cross-section tapering toward the mouth of said groove so that tension on the strings tends to wedge said anchoring members more tightly in said groove.

17. A racquet according to claim 16 wherein said mouth is defined by opposed lips extending from the tapered sides of said groove.