US2552020A

US2552020A - Tennis racket

Info

Publication number: US2552020A
Application number: US44810A
Authority: US
Inventors: Tribelhorn Emil
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-08-18
Filing date: 1948-08-18
Publication date: 1951-05-08
Anticipated expiration: 1968-05-08

Description

y 8, 1951 E. TRIBELHORN 2,552,020)

TENNIS RACKET Filed Aug. 18, 1948 Patented May 8, 1951 UNITED STATES PATENT ()FFlCE 1 Claim. 1

The present invention relates to a tennis racket characterized by having the points of fixture of the catgut strings in the frame protected against mechanical and temperature influences.

For this purpose the arrangement is such that the points of fixture of the catgut strings in the frame lie in a groove disposed longitudinal and which groove is covered towards the outside by a covering strip of heat and damp insulating material. With advantage a stepped grooving with an inner and an outer groove is formed in the frame, whereby the inserted catgut strings rest on the inner groove and the covering strip is clamped into the outer groove.

The annexed drawing shows by way of example a form of embodiment of the present invention, in which:

Fig. 1 shows the tennis racket in partial plan view,

Fig. 2 a partial side view thereof,

Fig. 3 a section through the frame of the racket, and

Figs. 4 and 5 a section through two detailed alternatives of execution of the frame of the racket.

According to the preferred construction shown frame I of the racket is provided on the outside of its circumference with a stepped groovin by which an inner longitudinal groove 2 and an outer longitudinal groove 3 is formed. Frame l is provided with holes 4 for stringing the catgut strings 5. The inserted strings 5 rest on the inner groove 2. Into the outer groove a covering strip 6 of heat and damp insulating material, such as vulcanized fibre, synthetic resins and the like, is fitted. The covering strip 6 protects the points of fixture of the strung-in catgut strings against mechanical action, i. e. damage, and atmospheric influences.

The

grooves

2 and 3 are out exactly to measurement as regards depth and width by means of a moulding machine, so that the frame has the same strength and stiifness around the whole of its circumference.

After the strings 5 have been strung on the inner groove 2, the covering strip 6, exactly cut to size, ground and polished, is inserted in the outer groove 3. Said strip is fixed in the frame by means of the screws 1 with the counter-sunk nuts 8. The fixing of the covering strip by means of screws is provided for the purpose of enabling an easy removal and re-assembly of the covering strip when the racket is being re-strung.

In the preferred construction shown the

grooving

2 and 3 is only brought round as far as the heart piece 9, since the strings leading thereto are fixed to it.

The covering strip does not need to consist of a single part. With advantage it can be made of laminated insulating strips which can be of various materials.

It is to be understood that the invention is not limited to the exact execution as it is shown and described herewith, but that various alterations and modifications can be made without narrowing the scope of the invention.

. The frame I can with expediency be formed of several strips glued together as is shown in Figs. 3 to 5.

In order to be able to give the frame I a relatively thin cross section, but nevertheless to give it a high power of resistance, said frame, as can be seen from Fig. 4, can be provided with an insert of resistant material such as a band ill of steel or a corrosion resistant aluminum alloy.

The alternative according to Fig. 5 differs from that shown in Fig. 4 essentially by the strengthening insert Hi being provided bilaterally on each side thereof with a narrow rib II. The circumferential edges of the ribs H are with expediency attenuated so that on pressing together the frame formed of several strips said ribs are forced into the adjacent strips whereby a particularly solid bond is achieved.

What I claim and Wish to secure by Letters Patent is:

In a tennis racket or the like a frame, said frame having inner and outer grooves therein, said inner and outer grooves opening into one another, said outer groove being open to the outside of said frame, said inner groove being narrower than said outer groove, said frame having a plurality of openings therethrough from the inner side of said frame to said inner groove, strings inserted through said openings and seoured to said frame, said strings bein in contact with the inner surface of said inner groove and resting in said inner groove, a covering strip inserted in said outer groove and secured to said frame, said outer groove comprising a seating for said covering strip.

EMIL TRIBELHO'RN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 364,596 Luce June 7, 1887 1,156,340 Bancroft Oct. 12, 1915 2,004,609 Johnston June 11, 1935 2,335,629 Audreef Nov. 30, 1943