US2131756A

US2131756A - Rubber ball

Info

Publication number: US2131756A
Application number: US692388A
Authority: US
Inventors: Fred T Roberts
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-10-06
Filing date: 1933-10-06
Publication date: 1938-10-04
Anticipated expiration: 1955-10-04

Description

F. T. ROBERTS 2,131,756

RUBBER BALL Original Filed Oct. 6, 1953 2 Sheets-Sheet 1 Jaw/y 7 WWW 3% 79%;, K /M SEW Oct. 4, 1938. I T, ROBERTS 2,131,756

- p RUBBER BALL Original Filed Oct. 6, 1933 2 Sheets-Sheet 2 Patented Oct. 4, 1938 a UNITED STATES PATENT Application Octoberfi, 1933, Serial No. 692,388

Renewed June 12, 1937 '16 Claims. (01. 273-61) "This invention relates to a ball, suitable for use My invention is illustratedin the drawings in athletic games, particularly the type used for hereof, which disclose the ball in various stages playing tennis and similar games; of manufacture and invarious modifications, and

r copending application Serial Number thereby illustrate also the method of manufac- '5 504N67 filed December 26th, 1930 (now P'atent ture. 1

No. 13964308) of which the presentinvention is I the drawings Fig. 1 is a view-f half of the an improvement, sl-lows, describes and claims a ball with the ribs formed on the outer surface ball having on the interior thereof ribs integral thereof, preliminary 130 introverting; Fig. '2 is' a with the wall of the ball, serving to resist -inview similar to Figland showing an alternative ward distortion of the wall and thus giving the method of arranging the ribs on the ban; Figi 3 ball resilience. in that application, however, the is a View of the half-ball shown in Fig. 1,'afterit ribs are shown in theform of meridians extendhas been turned inside 0111 F g- Partly ing from either the poles or small polar circles. in-sectionof a ball formed-by joining two halves, Igfound, however, that such ribs are farther apart like Fig. 3, and shows a wrapping which maybe 15. than desirablein theequ'atorial region of thelball, applied outside of such ball, while Fig. 5 is a secor if theyare made close enough together in this tional view through the finished ball of region there is too great a concentration-of rubshowing'a cover cemented in place; 'Fig. repreb'ennc'ar the poles. In either case the degree-of sents a standard ball to which the wrapping'has rebound of the ball is variable over a-surface, thus n ppl F 7 V w, par ly in ec i n,

interfering with its employment where accuracy of ai-ball Of the character described, before said 20 Qfireaction i required, ballhas been wrapped,whi1e Fig. 8 isa view part- In the present invention I provide ribs on the y se t o o e ba f gaft r thesame interior of the ball integral W'ith'the wall, as has been W pp and C p etedflaim'ed 5111 my Pppigr application, but I now ar- The halves (if the 108111, molded aS in 1 01 range these ribs to form anetworkon the inside F g- -O O e 'sim'ilar'manner, are cured Sum- 25 of the ball, thus making the spherical surface ciently to cause a permanent set in the rubber. more unifornily'braoed onth interior. I have found that a three four ths cure will ac- A further advantage of this application in adcomplis'h the result desired. "The halves are then dition to its uniformity and increased liveliness introverted as shown n F gd j d lies in the fa'ctthat it may be inflated to retain gether in an atmosphere of compressed air of it:

its region between the ribs sphere with a lower omp r tively low pressure, 11 Which t me the internal pressure than heretofore. This-not only ba e e ves a fi i u is also possible,

simplifies the operation of manufacture but'is an however, to Completely Cure halves in the D advantage in the durability of the balls, as there S oWn in Figs. 1 0r 2, and thereafter turn 35. isless leakage and hence, they remain lively for a halves inside out, place the free es tO- longer period of time. gether and cold-cure the joint between them. In making my improved ball, I may form the A s the flat on may be by other 'well kno-wn network of ribs on the interior surface of commeans/if desiredpli'ment r halves, Whichimay b sempcured d I The ball of which half is shown inFigs. land 3 40 later'p'laced together and joinedtoform a com: has a l W p' 'fli d W th su an- 40 plate ball with any desired degree of inflation. tiiilly meridian IYlbS latitudinal ribs -a mid- I prefer to make the ball by the method here'in qtlato al rib i-3,a di s rundisclosed, of forming ribs on the external surface Hing from e ju ctio P i -O meridian ribs of the halves of the ball, curing the halves su'ffiwith the latitudinal ribs, to a p int on the equaciently to give the rubber-a permanent set, then toria'l rib substantially "midway between the me- 45 introverting the halves, or turning "them inside ridian ribs. The ribs are formed in the mould out, and joining them together by any wellwhich forms the ball so that the ribs are integral known method. withlthe wall Ill. "The meridian ribs may 'join at :My invention comprises also applying an extethe pole '28, or maybe connected to a po'lar'circle rior mapping to such a ball, tending to comas'shown in my'Paten't No. 1,964,008. 50

press the ball and counteracting the expanding In the modification shown in Fig. 2, the meridforce. A'ba1l constructed in this novel manner ianr ibs It), the latitudinal ribs ligand theequarebounds much more quicklyafter striking'a'surtor'ial rib is aresimilar to those in Fig. '1, but in face, and is more satisfactory Where a'veryllively this case 'the meridian ribs extend only from the 55. ball is required. p'oleit'oth'e latitudinal ribs l l. The diagonalribs HI extend from these junction points equiangularly toward each other to meet at the equatorial rib. This arrangement is substantially equivalent to Fig. 1, with the portions l5 of the meridian ribs left out. In any case, the arrangement of the ribs should preferably be such as to divide the surface of the ball into substantially equal unsupported portions, such as are indicated by the character It in Fig. 1 and I! in Fig. 2. This gives a uniform bounce regardless of the spot where the ballreceives a blow.

As pointed out in my Patent No. 1,964,008, when the ball is formed in the above-described manner, (the ribs being first formed on the outside of the ball, which is later introverted to place the ribs upon the inside) the ribs are thus finally constrained into a smaller space than that in which they were given the original cure, and are thus given a permanent compression. This causes the ribs to exert a spring-like action in the interior of the ball and greatly increases the resilience thereof.

When joining together the two halves of the ball to form the completed ball, it is preferable that similarly situated ribs on the two halves of the ball register to form a continuous pattern as shown in Figs. 4 and 5. However, the equatorial .rib overcomes the necessity for such accurate registration as is required in my former ball. The "equatorial rib portions it formed on the halves will preferably be of slightly less thickness than the other ribs, as these two ribs, when placed together should form a rib substantially corresponding to all the other ribs of the ball to promote uniformity.

The halves of the ball may be joined together in an atmosphere of compressed air in the wellknown manner if desired, and thus the pressure within the ball may be nicely controlled. I have found that a ball formed with the network of ribs as above described makes a very lively ball, even though just suificient air is placed therein to retain its shape.

A more lively, though more expensive, ball may be made if sufiicient pressure is placed within the ball to slightly distend the unsupported portions [5 of the ball surface beyond the normal spherical contour of the ball. An outside wrapping of thin strips of cured rubber 30 may then be Wrapped tightly around the exterior of the ball, forcing the distended portions [6 back into their normal contour. The method of thus wrapping a ball is disclosed and claimed in a copending application of mine. Such a ball may then be finished by cementing the ball over the wrapping as at 3!, covering it with felt, indicated at 32 and giving it a final cure to cure the cement.

In making my improved ball, I may take an inflated spherical ball, having smooth interior and exterior surfaces, and wrap the same with thin rubber bands 39, as indicated in Fig. 6. Such a wrapping with any thin rubber band will improve the ball, but preferably I use a very wide and thin, cured rubber strand which is wrapped tightly about the ball in every direction and in a suflicient layer to create a compressive effect upon the ball.

Preferably, however, I take in place of a plain hollow ball one having internal ribs, similar to that above described. These ribs may be formed on the interior surface of the ball originally, but preferably I use the method disclosed in which the ribs are first molded upon the exterior of the halves of the ball, and sufficiently cured to give the rubber a permanent set. As disclosed in the said applications, the halves may be semicured to the proper point and finish cured when joined together. Or the halves may be completely cured and joined together by cold curing. In either case the halves are turned inside out after the first curing and secured together, thus placing the internal ribs under compression.

A ball, having internal ribs [0 and II, is shown in Fig. 7, there being unsupported wall surfaces l6 between such ribs. In one method of making this ball, after the halves are completed, their free edges are joined together in an atmosphere of compressed air sufiicient to distend the unsupported portions I6 of the Walls of the ball in the manner shown at 24. The best results are secured if the pressure is not sufficient to expand the portion of the ball carrying the ribs. This is particularly true if the ball is formed according to the method disclosed, where the ribs are under compression. It will be obvious that any expansion of the ball which materially extended these ribs would tend to nullify the expanding effect or resilient action of the ribs.

The ball of Fig. I may then have a wrapping of rubber bands 30 applied as described in connection with Fig. 1, thus constricting the distended portions 24 of-the unsupported walls of the ball back to their spherical shape, as shown in Fig. 8. This provides an extremely lively ball, as the internal compressed ribs and the internal fiuid pressure tend to expand the ball, while the wrapping of rubber bands creates a force in the opposite direction.

The ball of Fig. 8 may then be finished by applying a coating of cement 3| outside the wrapping, and a cover of felt 32 over all, and the ball may then be placed in a mold for a final curing sufiicient to cure the cement coating and hold the cover in place.

While the ball of this invention is not limited to any particular dimensions, a tennis ball, under the currently accepted rules, should have an external diameter of 2 inches. In making such a ball, by the preferred method illustrated in Figs. 7 and 8, I propose to first mold a ball half having a main wall about 1 inch in thickness, the mould having an external diameter of 2% inches, this defining the dimension of the main wall of the ball. The ribs will be A; inch outside of this or 2%.,- inches across the outside surfaces of the ribs. Then this half is inverted and joined to another correspondingly formed half in an atmosphere of compressed air, with just sufficient pressure to slightly bow out the thin wall between the ribs but not inflating the ball to over-size. I then wrap the ball so that the bowed thin places are brought down to the spherical surface of the ball. I then cover the ball with cement, place over this felt, and put the entire ball back into a mould 2%; inches in diameter and cure it enough to vulcanize the cover of the ball. The wrapping, cement and felt add 1% inch to the outside radius of the main wall of the ball.

This makes a ball having internal ribs which were molded so that their original outer surface before introversion had a diameter of 2 inches, but which when introverted to place the ribs inside the ball have an internal diameter of 2%,; inches. Accordingly, the original set of the ribs is retained, and thus the outward spring of these ribs, caused by their being compelled to occupy a less space than when formed, gives the ball the high resilience desired.

While this application is concerned with balls having an internal ribbed structure, (with or Without a wrapping of elastic strands), reference is made to my copending application Serial No. 228,093, filed September 2, 1938, for claims on a ball having a central sphere with an elastic winding thereon irrespective of the internal construction of such sphere. Reference is also made to my copending application Serial No. 112,572, filed November 24, 1936, for the method of making the ball herein disclosed.

I claim:

1. A hollow rubber ball having internal fluid pressure, ribs on the interior surface of said ball spaced with respect to each otherto form spherical triangles, and an exterior covering of tightly wrapped rubber bands to reinforce the portions shape, and means on between the ribs.

2. A hollow spherical rubber ball having a wall, meridian ribs integral with said wall, a network of diagonal ribs on the interior. surface of said wall and integral therewith, there being unsupported portions of said wall between said ribs, fluid pressure within said ball adapted to distend said portions of the wall beyond, the normal;

spherical surface of said ball, and a wrapping of rubber bands on the exterior surface of said ball to reinforce said portions.

3. A hollow rubber ball having a wall, a network of intersecting meridian ribs and latitudinal ribs intersecting each other, on the interior surface of said wall and integral therewith, there being unsupported portions of said wall between said ribs, fluid pressure within said ball adapted to distend said portions of the wall beyond the normal spherical surface of said ball, a wrapping of rubber bands on the exterior surface of said ball, to reinforce said portions I a coating of cement over the wrapping and a felt cover outside the cement.

l. A hollow, rubber ball, comprising a wall,

internal ribs on the inside of said wall, compressed to a greater extent than the said wall, whereby an indented outer surface is formed, and means on the exterior of said wall to compress the upstanding wardly, whereby said ball attains a smooth, spherical shape.

5. A hollow, rubber ball, comprising a wall, internal ribs intersecting at points spaced over the entire surface on the inside of said wall and compressed to a greater extent than the wall, whereby said wall is distended from spherical the exterior of said wall to compress the extended portion inwardly to cause the ball to assume a smooth, spherical shape.

6. A hollow, spherical, rubber ball, comprising a wall, internal ribs on the inside of said wall, compressed to a greater extent than the wall, whereby humps are formed'between the rib por tions and adjacent wall portions, and the ball is distorted from a true spherical shape, and means on the exterior of said wall to compress the same inwardly, whereby said ball attains a smooth, spherical shape. 7

'7. A hollow rubber ball comprising a wall, internal ribs on the inside of said wall compressed to a greater extent than said wall, whereby the portions of the ball surface in exterior of said wall is distorted from a true ribs having their outer convex boundaries joining the inner surface of the wall and their inner. concave boundaries unattached, latitudinal ribs extending around said wall on the inside thereof and intersecting said pole ribs, said latitudinal ribs extending over substantially the entire ball surface, said intersections occurring at points spaced over the entire surface of the ball, and especially intermediately of the equitorial plane of the ball and each pole point.

9. A hollow rubber ball, ribs on the interior surface of said ball, spaced with respect to each other to form spherical triangles, and an exterior covering of tightly wrapped rubber bands to reinforce the portions between the ribs.

10. A hollow, spherical rubber ball, having a wall, meridian ribs and diagonal ribs on the interior surface of said wall and integral therewith, there being unsupported portions of said wall between said ribs and a wrapping of rubber bands on the exterior surface of said ball to reinforce said portions. 1

11. A hollow, rubber ball, having a wall, a network of meridian ribs and latitudinal ribs intersecting each other on the interior surface of said ball and integral therewith, there being unsupportedportions of said ball between said ribs, a wrapping of rubber bands on the exterior surface of said ball to reinforce said portions, a coating of cement over said wrapping and a felt cover outside said cement.

12. A hollow rubber ball, spaced ribs on the interior surface of said ball and an exterior covering of tightly wrapped rubber strands to reinforce the portions between said ribs.

13. A hollow rubber ball, spaced ribs on the interior surface of said ball, an exterior covering of tightly wrapped rubber strands to reinforce the portions between said ribs, and a felt cover secured to said ball outside the covering of rubber strands.

14. A hollow rubber ball having internal rubber ribs compressed to a greater extent than the wall of the ball, and a wrapping of stretched rubber strands on the exterior of the wall.

15. A hollow rubber ball having internal rubber ribs integral with the wall of the ball but compressed to a greater extent than the wall of the ball and a wrapping of thin elastic strands on the exterior of the wall.

16. A hollow rubber ball having in its interior circular ribs in the position of parallels of latitude and ribs extending at an angle thereto, the latter ribs being under longitudinal compression and -serving to support the ball surface at regular