US1682199A

US1682199A - Egbert h

Info

Publication number: US1682199A
Authority: US
Publication date: 1928-08-28
Anticipated expiration: 1945-08-28

Description

Aug. 28, 1928. 1,682,199

R. H. SMILIE TENNIS RACKET Filed Dec. 17 19 7 :E lml,

INVENTOR Robe/'2" H. 501/71? Patented 28, 1928.

ROBERT H. SMILIE, .OF OAKLAND. CALIFORNIA.

TENNIS BLACKET.

Application filed December 17, 1927. Serial No. 240.722.

Myinvention relates to improvements in tennis rackets. The game of tennis is found.

to be a rather expensive game, for one reason due to the rapid wearing outof the strings of the rackets used. On the close observation under a microscope of the playing surface'of a racket I have discovered that invariably the strings break down at their intersections or crossings. This of course may be eX- plained as caused by the frictional engagement between the strings for although a racketmay be very tightly strung there is always a more orless lateral motion of each-string with respect to the strings with-which it is interlaced. Each impact bet-ween the ball and the racket causes the strings of the intersections so brought into play, to be pressed together andso bruise and permanently injure their contacting surfaces. My observation: also disclosed the fact thaton an impactibet-ween a ball and racket, at most four strin are actually brought into contact with the ball. and due to the fact that the coeflicient of friction ofv string on string is insufficient to prevent the lateral motion of one string with respect to its intersecting string, the load placed on the racket by the-impinge ment with the ball is earriedlargely bythe fourstrings so brought into contact.

In general it is the object of my invention to provide an insulating means between the intersecting strings of a racket and thereby to prevent the frictional engagementof such intersecting strings and consequently to prevent their bruising and wearing.

.Another object of my invention is the provision of means whereby the load placed on a racket by its impingement with a ball, will be more or less evenly distributed on all of 'its strings thereby eliminating any undue strains from being placed on any one string.

.Another object of my invention is the provision of a flexible. double concaved disc to be interposed between intersecting strings of a racket and in which the intersecting portions of said strings may be embedded and embraced thereby.

Another object of my invention is the provisions of an insulating disc adapted to be interposed between the intersections of the strings of a racket. and which is made of a material. the coefficient of friction of which on the strings of a racket is greater than the coefiicient of friction between string on string. and which will therefore prevent the strings from creeping.

My invent-ion possesses other advantageous features, some of which with the foregoing will be set forth at'length in the following description wherelI shallou'tline in fullf'that form of the tennis racket of myinven'tion which I have selected for illustration-in the drawings accompanying and ."forming part of the present specification. -Ailthough I have shown in the drawingsbut oneform-of my invention, I do not desire "to 'be'limited thereto, since the invention as definedin the.

claims .may'be embodied in other "forms. also.

Referring to the drawings: .Fig. 1 is an elevational view of a tennis racket embodying the use ofiny invention.

Fig. 2 is aplanview ofmylfiexiblmdorible concaved insulating disc. 7 Flg. 3 1s a mid-section.of-lthelinsulating dlsc shownin Fig. .2.

-5Fig. 4 isa sectional view takenrparallelto one set of intersecting :strings of araket showing thermanner .in which. insulating discs are interposedlbetween .the intersections of a string.

Fig. 5 is a mid-sectional view of' areenforcedinsulating disc.

lFig. '6-is aperspective viewof la sstring tersection showing themannen in which: such intersecting strings are :enibedded and .embraced inan interposedinsulating disc.

In accordance with myinventionrmy im sulating disc .1 .is preferably moldedofrubher or other.iiexiblematerial. Eahfface of my insulating discf is dished or "concave ..as at .2 and 3. In.aetual practice lhave.made these discs of a diameter approximately. equal to threediametersofthewstrings.on a racket butthey may :ofcours'e'be madeof any other suitable .size. These Iins ilating discs are then interposed between. intersections of the stringsof'..apracket-and whenrso interposed .are found tox assume .the formation as best shown in Figs. 4 and 6. Referring particularly to 6. the string 4: of a pair of intersecting strings 4 and 5 is embedded within the upper surface of one of my insulating discs while the string 5 is embedded in its lower surface. It will be noted that the string 4 engages with the peripheral portions 6 and 7 to cause these peripheral portions to embrace the string 5 and that the string 5 engages the peripheral portions 8 and 9 so as to cause these peripheral portions to embrace string 4. The material. of which these insulating discs are made is so chosen that its coefliecient of the friction on the strings is substantially greater than the coeflicient of friction between a string on a string. By having such an increased coeflicient of friction and due to the manner in which the intersecting strings are embedded and embraced within the insulating discs the strings are prevented from creeping or moving laterally on each other thereby decreasing the frictional wear of the strings.

It has been found that the resiliency of a racket constructed in accordance with my invention is greatly increased thereby producing a faster racket. To further increase the resiliency of the racket and to increase the durability of my insulating discs I have found it preferable to reenforce the insulating disc by means of a centrally disposed fibrous disc 11 as shown in Fig. 5. This fiber reenforcing -1nember is embedded in and made integral with the insulating disc. In this form of insulating'disc it is'to be noted that at its center its thickness is substantially that of the fiber reenforcing member. When such an insulating disc is interposed between intersecting strings, the fiber 11 is practically all that separates the strings and being harder V and more resilient than its surrounding rubber, responds somewhat faster to the action of the strings than an unreenforced disc. The fiber reenforcing member also increases the durability and life of the insulating disc, their life being about equal to the life of the strings. I Y

' The use of such insulating discs also has the effect of producing a greater and more even frictional surface between the racket and the ball thereby permitting a greater accuracy when it is desired to give a predetermined spin to the ball.

Although I have found it preferable to construct such an insulating disc of a flexible material, I have constructed some of aluminum. When so made they are molded to the form show in Fig. 6 and are provided with wedge shaped grooves for gripping the strings. These metallic devices serve to insulate or separate the intersecting strings but it has been found that their gripping action on the strings isnot as great as that of the rubber insulation.

, By preventing the lateral motion or creeping of the strings with respect to each other it can be seen that when there is an impmgement between a ball and the racket the load thereby placed on the racket, will be carried not only by the four strings with which the ball actually engages, but will be distributed to a plurality of strings adjacent these four strings. This of course decreases the chances of a worn or defective string from breaking due to carrying too great a portion of the total load and also insures a uniform playing surface at all times.

By the above disclosure it can be seen that I have not only provided a means whereby the life of the strings of a tennis racket is greatly increased but by the use of such means the playing qualities of a racket are also improved, that is, the racket is faster and enables the player to control more accurately the motion of the ball. Actually the life of the strings has been found to be doubled or tripled and that for a given amount of energy, the rebound of a ball when my improved racket is used, is much greater than with the rackets now in use.

I claim: I

l. A racket comprising aframe, a plurality of interlaced strings supported by said frame and a plurality of deformed double concave discs interposed between said strings.

2. As a new article of manufacture a disc of flexible material provided with a central reinforcing member and adapted to insulate the strings of a reticulated material.

3. As a new article of manufacture, a flexible double concave disc adapted to insulate the strings of a racket.

4. A tennis racket comprising a frame, a plurality of intersecting strings supported by said frame and a plurality of flexible centrally reinforced discs interposed between said strings.

5. A tennis racket comprising a frame, a plurality of intersecting strings supported by said frame and a plurality of flexible, double concave discs interposed between said strings.

In testimony whereof, I have hereunto set my hand.

ROBERT H. SMILIE.