US 1470878 A
Description (OCR text may contain errors)
R. H. ROBINSON TENNIS RACKET Filed Aug. 28
Patented Oct. 16, 1923.
ROY H. ROBINSON, OF CHICAGO, ILLINOIS.
Application led August 28, 1922.
70 all whom t may concern.'
Be it known that IE ROY H. ROBINSON, a citizen ot the United States, residing in Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Tennis Rackets, of which the Atollowing is a specification.
This invention relates to rackets tor lawn tennis, but more particularly to such as are provided with a metal trame, and has for its primary object to produce a trame construction o this type which will no-t cut the strings of the racket.
Further objects are to provide an improved method of Stringing the racket, to permit adjustment of the sti-inging in the racket. and in general to provide an iinproved racket.
Metal tennis racket Ytrames are preferable to the present wooden type because of their greater strength and reduced air resistance. The only serious disadvantage of this type et Ytrame has been the 'frequent cutting of the strings. Tire strings have been tried as a substitute for the usual gut but these have less resiliency and are also cut by the metal edges, although less quickly than the gut.
In order to obviate the disadvantages and retain the advantages of the metal trame racket, I have provided the Jframe with a` cushioning element which prevents the strings from coming in contact with the metal. Also I have provided a new method ot' Stringing which eliminates the sharp bearing angles tor the strings on the frame. My improved stringing likewise distributes the blows on different strings throughout the longitudinal zone et impact which in the present type ot' ackets tall principally on the central longitudinal strings. The adjustability ot the trame permits the Stringing to be tightened or slackened at will and is particularly advantageous because it relieves the strain upon the stringing when the racket is not in use and permits the tension to loe varied in accordance. with weather and other conditions.
The many other objects and advantages et my invention will be better understood by reference to the following specification when considered in connection with the acempanying drawing illustrating certain selected embodiments thereoin which:
Fig. 1 is a front elevation of the racket.
Serial No. 584,619.
Fig. T illustrates a modified form of Stringing.
Referring to the drawing and particularly to Figs. 1 to et. the racket comprises a trame 10 provided with the usual. handle 11 and sti-inging 9. The trame 10 varies somewhat in form in various models of raf het but is substantially oval in shape and is provided with a shank 12 upon which the handle is secured. The particular desifrn ot racket 'trame illustrated in Fig. 1 oi the drawing is similar to that ot a wellltnown make in which the trame is tubular in form. The shank 12 is formed ot a pair ot' tubes 13 which have their outer ends welded to the frame 10. The handle 11 is et wooden construction and is driven upon the tubes 13. .i metal ferrule 14 envelops and supports the forward end et the handle 11. In my improved construction the metal Jframe 10 is indented in its outer tace to form a longitudinally extending fhannel 15 within which lits a cushioning strip 16 et leather. fiber, or other suitable material. The outer side of the metal tubing. which alone carries the Stringing 9.
'is initially slitted at 1T in the manner indicated in Fig. 4: and the prongs 17 rounded downwardly to provide a smooth bearing surface. havingno sharp edges or angular turns to eut the gut strings. The inside wall T ot the tubular training is longitudinally slotted at intervals as at S to permit the strings to pass inwardly and outwardly without contacting therewith. The cushion 1.6 slitted in substantially the same manner as the upper or outer wall ot the tube and maintains the strings out ot contact therewith. as indicatedV in Fig. 2. It wire sti-inging is used the cushioning element might be omitted as the rounded bearing surfaces would vnot cut this material.
Instead ot Stringing the racket in the usual manner with the strings extending llU fifi
longitudinally and transversely of the frame, I have provided a new iorm oit Stringing in which the strings run obliquely ot the trame. This form of Stringing has many advantages which make it preferable for either wood or metal frame racket-s, but in the case oit metal trame racliets it is particularly desirable because each string as it passes through the traine is merely turner through au angle ot about 41:5 degrees instead making a complete turn or reversal ot direction. It has been found in practice that practically all the impacts of the ball occur in a central strip extending longitudinally ot the rachet so that in the present type ot racket a gtew of the longitudinal strings receive practically all of the impacts and it is these strings which usually break i'irst. In my improved form ot oblique stringing these impacts are distributed over practically all the strings. Furthermore, the strings receiving the majority et impacts are shorter in length than in the present type of bracket. In the majority ot strolqcs the racket is caused to strike the ball a glancing blow which usually occurs approxi- -inately along the lateral axis ot the rachet or at a right angle to the longitudinal strings and parallel'tothe lateral strings in the 'form ot Stringing hitherto employed. '.lhe object of this is to produce a spin upon the hall. The amount oit spin depends upon the 'friction created by the contact ot the bail with the strings of the racket. lthas been found that my improved form ot stringing very materially increases the trictional resistance and thus proportionally increases the spin. Another advantage of my oblique Stringing is that it permits the tightening or loosening et' the strings by the adjusting ot the size ot the iframe which would not be possible in the present form ot stringing.
In order to make possible the adjustment of' the rachet frame to either tighten or loosen the stringing, I have provided in the 'trame small turn-buckles 18 consisting ot an interim-ly threaded -ive 19 litting upon op positcly threaded screws 2li set in the fijfposiug en( s ot the trame. The sleeve 'i9 preferably of substanl'ially the same ci;- lerior size as the metal tubing ot the bracket. The s 1e ve 2l) is provided with ay series or' perforations to permit it to be turned by a small pin or lcey. lllheu these turn-buckles are located at the top and bottom ot the trame, as indicated in Fig. l, each side oi the rachet iorms an arch, and when this is pushed outwardly by the screws the strings are not only tightened but the tightening ot the `nearest strings :torces out the arch in the rei Yer until an equilibrium in the. tightening o t' all et the strings is reached. It only one turn-buckle is to be used it `is advisable that this belocated at the bottom or handle end of the `frame so that the trame may be contracted or spread at this point. The spreading ol the lower arch ot the racket tightens both sets of strings at their .lower end and accordingly the entire stringing ot the rachet. Any other well-known method ot adjusting the size ot the traine may be used in place ot the tiun-buclilc described. lnstead ol placing the adjusting elements at the top and bottom ot the iframe, or at either ot these locations, the adjusting elements may be placed on opposite sides oit the racket and this form is advantageous where more longitudinally oblique stringl is used. The oblique Stringing and the adjustment oi? the trame are equally applicable to both metal and wooden `trame rachetfli, as will be readily evident.
Instead ot using a tubular metal trame, such as has been described in connection with Figs. l to al inclusive, a braced troughshaped trame 30, such as is shown in Figs. 5 and 6, may be used. In this` trame the side members Si join in a comparatively sharp edge 32 and the outer edges ot these sides are prete ably rolled over at 3i-l. Metal ties 3ft connect these outer edges at suitable intervals and properly brace the trame. A liller oit' tiber, wood, leather, or other suitable material, is placed within the trough and is held in place therein by the outer rolled edges thereof. This tiller is punched or cut away, as at 36, to permit the passage ot the strings therethrough and iorms the cushion for these strings in the same manner as the strip 16 in the previous embodiment. This form of frame is not only neat in appearance but its concave faces coming to a substantially sharp edge between the stringing con torni wel l to the ball and practically eliminate what is linown as wood shots. The playing area of the rachet is extended practically to the outer edge or the frame.
Instead of the form ol' single Stringing illustrated in Fig. l, the strings may be grouped in pairs with a slight interval between the springs in each pair, in the manner indicated at l() in Fig. 7. This torm ot stiinging is advanlageous, as it provides larger openings Jr-l for the ball to sink into without reducing the number oli strings.
lVith my improved form ol racket it is possible to use gut Stringing and the strings will not be cut by the metal ot the trame. The oblique form 0l Stringing increases the playing efficiency ot the racket and the wearing qualities of the same. It also makes possible the adjustment of the trame with the benefits set forth.
I am aware that many changes may be made in the construction and arrangement olparts without departing from the spirit of my invention, and I reserve the right to make all such as lfairlyv tall within the scope oit the following claims.
I claim as my invention:
l. A tennis rachet comprising a substantially oval shaped tubular metal frame having a channel formed in its periphery and extending longitudinally thereof, a strip of yielding material fitting Within said channel, stringing woven through said frame and said strip, and a handle connected to said traine.
2. A tennis racket comprising a tubular frame having its outer wall slitted at inter vals and the metal pressed inwardly to form a series of string-bearing surfaces, a handle connected to said frame, and Stringing passing through the inner wall of said 'trarne and about the bearing surfaces on said outer Wall.
3. A tennis racket comprising a tubular frame having a series of longitudinally spaced slots formed in its inner wall and its outer wall slitted at longitudinal intervals with the metal turned inwardly to form a series of rounded string-bearing surfaces, a handle connected to said frame, and stringing passing through the slots in the inner wall of said trame and about the corresponding string-bearing surfaces on the outer wall thereof.
Il. A tennis racket comprising a substantially oval shaped frame divided transversely on the longitui'linal axis thereof` au adjusting element disposed between the opposing ends of said trame, a handle Connected to said frame, and stringing woven through said frame.
5. A tennis racket comprising a substantially oval shaped frame divided transversely on the longitudinal axis thereof, a turn-buckle connecting the opposing ends @t said frame, a handle connected to said trame, and Stringing woven through said frame.
6. A tennis racket comprising a substantially oval-shaped frame having a channel therein and extending longitudinalhv thereet, a strip ot yielding material fitting within said channel and retained therein by the conformation ot' the walls ot' the channel, stringing woven through said frame and said strip, and a handle connected to said frame.
7. A tennis racket comprising a metal traine having a series of substantially H- shaped slits provided therein and the prongs formed by said slits pressed inwardly. a
handle connected to said frame, and stringing passing through the Openings formed by said slits.
8. A tennis racket comprising a tubular metal frame having a series of slots formed in its inner wall and its outer wall provided with corresponding substantially H-shaped slits, said outer wall being indented t0 provide a longitudinal channel therein and having the prongs formed by said slits bent inwardly, a strip of yielding material extending longitudinally of said frame within said channel and slitted t0 correspond with the Wall thereof, Stringing woven through said :trame and said strip, and a handle conneeted to said frame.
9. A tennis racket comprising a substantially oval-shaped frame divided transversely at opposite points, adjusting elements located at each of the points ot' division, a handle connected to-Said frame and Stringing woven through said fra-me.
l0. A tennis racket comprising a substantially oval-shaped frame, Stringing woven through said frame with one Set of strings disposed at an angleto the other set, an adjusting element incorporated in said frame between said sets ol strings, the strings oleach set engaging the frame on opposite sides of said element and a handle connected to said frame.
l1. A tennis racket comprising a frame having an open throat, an adjustable member forming the sole connection between the sides of the frame at the throat, a handle connected to the ends of the traine, and Stringing woven through said frame.
l2. A tennis rachet comprising a substantially oval-shaped trame, obliquely arranged Stringing woven in said frame, means disposed between the sets of Stringing for adjusting said frame to vary the tension of said Stringing, the strings of each set engaging the frame on opposite sides ot said means and a handle connected to said frame.
13. A tennis racket comprising a substantially oval-shaped metal frame having pertorations therein to admit the Stringing, Stringing woven through said pei-iterations. cushioning means interposed between said Stringing and said frame and retaining said Stringing out et contact with said frame. and a handle connected to said frame.
ROY l-l. ROBINSON.