US2901252A - Racket stringing device - Google Patents

Description

Aug. 25, 1959 WATSON Q 2,901,252

RACKET STRINGING DEVICE I Filed Feb. 25, 1957 INVENTOR.

DflN/EL A. MEG

BY mm B W ATTORNEY RACKET STRINGING DEVICE Daniel K. Watson, Rockville, Md.

Application February 25, 1957, Serial No. 642,102

2 Claims. (Cl. 273-43) This invention relates to improvements in racket stringing apparatus and more particularly to a new and useful means for preventing slippage of the string when tension is being applied thereto during the stringing operation.

There are several types of mechanisms or apparatus now known and used to assist an operator in stringing tennis and other game rackets with gut or nylon or other stringing material. of stand on which is mounted mechanism for holding the racket in position to be strung, and means for applying tension to the string after each row has been strung, and also means for holding the strung strings under tension. One of the problems encountered in such de vices is that the slippage of the string will occur when tension is being applied thereto as each row or course is formed. It is of course true that gripping jaws which clamp the string may be provided with rough and sharp gripping surfaces but, while these prevent slippage, they injure and severely weaken the string. To overcome this drawback attempts have been made to employ drumshaped snubbers of rather sizeable dimensions and the surfaces of which are provided with rubber or similar material. In practice the string would be wound thereabout to create a snubbing action. For a number of reasons these have not solved the problem. Not the least of these reasons is that the surface would become out with grooves and particles would injure the string. Moreover, because of size such devices could not be moved into close proximity to the racket frame.

It is a principal object of the present invention to provide a device which overcomes these disadvantages and provides for the first time a satisfactory mechanism for preventing slippage of the string while the same is being pulled under tension and in such manner as not to injure the string in any manner.

It is another object of the invention to provide such a device as may be applied to racket stringing devices when manufactured, or to existing devices now in use.

The device, according to the invention, is simple in construction, easy to manufacture and install, and is inexpensive. The invention has as an object the attainment of such attributes.

These and other objects of the invention will become more apparent from the following description and claims when read with accompanying drawings, in which:

Fig. 1 is a side elevational view of the upper portion of a racket stringing apparatus, showing the invention as applied thereto;

Fig. 2 is an enlarged end view of the invention;

Fig. 3 is an enlarged side elevational view of the same; and

Fig. 4 is a top plan view of the same.

While the invention relates to but one mechanism to be used with racket stringing apparatus, it is necessary to refer to racket stringing devices generally so as to make clear the positioning, operation and purpose of the invention. While as will be apparent hereinafter, the

rates l atent Generally, these embody some form r Patented Aug. 25, 1959 invention can be employed with all racket stringing apparatuses with but little or no modification, it will here be described as incorporated in one of the more common types.

With reference to the drawings one such common type of racket stringing apparatus is supported by a tubular post or pedestal only the upper end 10 of which is seen in Fig. 1. This upper end carries the mechanism for the support of a racket to be strung and for effecting the positioning and tensioning of the strings during the stringing operation.

The upper end wall 11 of the tubular post 10 has pivotally attached thereto by means of a pivot pin 12, one end of an elongated plate 13, the plate being mounted for movement in a horizontal plane. The other end of the plate 13 extends laterally of the post 1d and has a block 14 secured rigidly to its upper face. Extending from this block 14- in an upwardly inclined direction so as to overlie the plate 13 is an arm 15. The upper free end of the arm 15 is provided with means for supporting a portion of the frame of the racket 16. From Fig. 1 it will be seen that the upper end of the arm 15 carries a pair of gripping jaws 17 which engage the throat of the racket. The jaws are moved into gripping engagement with the racket by means of a thumb screw 18.

The block 14 has a rectangular opening therein to receive one end of an elongated bar 19, the bar being thus mounted for longitudinal slideable movement, a set screw 20 being provided to secure it in any desired adjusted position.

On the other end of the bar 19 is rigidly secured another racket supporting arm 21 similar in design to the arm 15. The upper free end of the arm 21 has racket frame gripping jaws which are actuated by means of the butterfly nut 22.

The upper end of the supporting post 10 is provided with diametrically opposed housings 23 to support a rod 24 of rectangular cross-section which extends through them and the post 10. The housings 23 may be provided with anti-friction bearings (not shown) to facilitate longitudinal sliding movements of the rod 24.

The end of the rod 24 adjacent the racket supporting arm 21 is offset as shown at 25 and rigidly supports the upstanding string puller arm 26. It is this arm 26 which incorporates the special features of the invention, as will later be more apparent. The string puller arm 26 incorporates string gripping jaws 27, 27 (see also Figs. 2, 3 and 4) actuated by the lever 28, and also carries a specially designed snubber element 29 carried by a plate Stl'which may be attached to the gripping jaw 27 by means of rivets, screws or the like 31. The arrangement is such that a racket string 32 is wrapped around the snubber element 29 and then passed through the gripping jaws 27, 27 in which they are then gripped by moving the lever 28 downwardly. The string 32 is then placed under tension through mechanism which. moves the rod 24 longitudinally and arm 26 (to the right in Fig. 1).

The particular mechanism for effecting this movement forms no part of this invention and therefore need not be illustrated or described in detail. Any number of such mechanisms are well known. For example, reference may be made to United States Patent No. 2,188,250 which shows such mechanism which employs a pulley wheel, weight and foot treadle connected so that when the treadle is pushed down by the foot of the operator the rod and arm under discussion will be moved longitudinally in string tensioning position, the release of the treadle permitting the weight to return the arm to its original position.

Nor is the invention concerned with any special manner for causing the handle 28 to actuate the gripping jaws 27, 27', as many such mechanisms are known and used.

a For example, one of the gripping jaws 27, 27 may be integral with the arm 26 while the other is mounted for movement with respect thereto by being mounted loosely on a spindle which passes through both jaws. The spindle may have cam elements rigidly secured thereon which engage the outer surfaces of the jaws and engage cam surfaces on the jaws so that movement of an actuating handle will cause the cam elements to engage their respective cam surfaces, thus forcing the gripping jaws together into gripping position. String clamps operated through such cam action are common in the art and reference can be made to Figure 6 of United States Patent No. 2,154,870 in particular.

For that matter, the racket stringing apparatus with which the present invention has been illustrated in Fig. 1 employs string clamps for another purpose, namely to hold the string under tension while the plate 13 is being shifted on its pivotal mounting 12 for placing the raclfet frame 16 in a position relative to the snubber 29 and gripping jaws 2'7, 27 for the tensioning of the next succeeding string section of the racket frame. Reference is made to the string clamps 33. There are two of these, though only one is shown in the drawing.

The string clamps 33 are carried by the upstanding arms 34 which are supported on rods 35 which are dis.- posed on each side, respectively, and parallel to the bar 19. These string clamps 33 are operated by the handles 36. Here again this mechanism does not form a part of the present invention, but if a further description is desired reference may be made to United States Patent No. 2,188,250.

The special snubber and string tensioning mechanism in accordance with present invention possesses requirements which must be adhered to to obtain the real benefits of the invention. For example, the snubber element 29 is substantially one-half inch in diameter and one-half inch long.

As will be noted, the snubber element 29 is rigidly secured by welding, or any other suitable method to the plate 30 while this plate, in turn, is rigidly attached to the arm 26 by rivets, screws or the like 31. The snubber element 29, as so mounted, isv positioned so that its horizontal axis is disposed between horizontal planes formed by the two rows of string holes 36, 36' in the racket frame 16 to be strung. When the string 32 is to be drawn through one of the holes of the upper row 36, it is then passed over the top of the snubber element 29, then around the snubber element and then between the gripping jaws 2'7, 27' which are then closed to hold the string securely. When the string, on another pass, is extended through a hole in the lower row 36', it is then passed under the snubber element, then up and around the snubber element, and thence between the gripping jaws. In each instance the proper tensioning to the string is then applied by pushing down the foot treadle (not shown) as heretofore described.

The snubber element is preferably constructed of steel or other hard metal. When constructed of such metal and of the dimensions: recited, a very effective snubbing action is obtained with no slippage. It is one of the important factors of this invention that such materials and dimensions be employed, or substantially so, since only by so doing does it appear that no-slippage snubbing of the gut string can be effected.

If so desired, the snubbing element may be formed from a metal tube which can be made replaceable.

It will be noted that because of the size, mounting and positioning of the snubber element 29 it can be moved very close to the racket frame. This leads to several advantages, one of which is that it permits operating even with short ends of string which can, even then, still be snubbed and gripped. Moreover, the straight line in which tension is applied is always maintained.

It should now be evident that the snubber may be made integral with the gripping jaw 27, or can, as shown, be made attachable. In the latter event it can be produced and sold for use by owners of machines not so equipped, for it is easily attached or removed.

While in a general manner there has been disclosed what are deemed to be practical and eflicient embodiments of the invention, it should be well understood that the invention is not to be limited thereto as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the invention as comprehended within the scope of the accompanying claims.

I claim:

1. In apparatus for stringing a racket and having means for securing the racket frame in a horizontal plane, string tensioning means comprising an arm mounted on said apparatus for movement toward and away from the frame of a racket secured in said apparatus, a small metal snubbing cylinder removably secured on said arm in a position to lie directly adjacent the frame of the racket at one end of movement of said arm, said cylinder being mounted with its cylindrical axis substantially in the horizontal plane of the racket frame and being of such a diameter that strings passed through holes in a row of spaced holes in the racket frame and passed around the snubbing cylinder remain in the plane of said row of holes between the holes and the snubbing cylinder, and means mounted on said arm on the opposite side of said cylinder from the racket frame for gripping a piece of string passed around said cylinder during the racket stringing operation.

2. Apparatus according to claim 1 wherein said snubbing cylinder has a diameter of substantially one half inch.

References Cited in the file of this patent UNITED STATES PATENTS 2,091,654 Roberts et al. Aug. 31, 1937 2,154,870 Serrano Apr. 18, 1939 2,188,250 Serrano Jan. 23, 1940 2,246,109 Serrano June 17, 1941 2,309,849 Kausal et al. Feb. 2, 1943 2,389,609 Caro et al Nov. 27, 1945

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