US2146853A - Apparatus for stringing tennis rackets and the like - Google Patents

Description

Feb. 14, 1939. A RYCKMAN 2,146,853

BRINGING TENNIS RACKETS AND THE LIKE APPARATUS FOR S Filed July 6, 1937 3 Sheefcs-Sheet l Apron/i=7 Feb. 14, 1939. x RYCKMAN 2,146,853

APPARATUS FOR STRINGING TENNIS RACKETS AND THE LIKE Filed July 6, 1957 3 Sheets-Sheet 2 P f .1 v,

Feb. 14, 1939. A RYCKMAN 2,146,853

APPARATUS FOR STRINGING TENNIS RACKETS AND THE LIKE Filed July 6, 1937 a Sheets-Sheet s INVENTOFL; flIDR/Eh' RyCKMAH.

Patented Feb. 14, 1939 UNITED STATES APPARATUS FOR STRINGING- TENNIS RAOKETS AND THE LIKE Adrien Ryckman, La; Panne, Belgium Application July 6, 1937, Serial No'.

In Belgium July 11 1936 1 Claim.

The present invention relates to an apparatus constructed for the purpose of stringing and restringing rackets and like articles with a minimum of fatigue and movement on the part of the operator.

At present, notwithstanding the existence of certain' machines already proposed for this purpose, different notorious drawbacks subsist, the main consequences of which consist in the necessity of placing some strings under an excessive tension and others under a deficient tension; the necessity of using a punch, which is particularly harmful for the strings; the difficulty of keeping the racket exactly in its shape; the impossibility of sustaining in a perfectly rigid manner that portion of the racket frame upon which the momentary traction is exerted for tensioning the string during the work; the impossibility of submitting to an almost uniform tension the strings arranged lengthwise and the transversely arranged strings; the difiiculty of exerting the tensional traction upon the strings exactly along the axes of the appropriate holes in the racket frame, and so on.

The present machine has ject the elimination of all these drawbacks, as it is constructed in such a manner as to enable the stringing operations of rackets to be performed under a practically constant tension, which may be perfectly predetermined. Moreover, means are provided to prevent any deformation of the racket during the work and permit the stringing of all models of frames or types of borings.

Moreover, the frame of the racket is supported in a practically perfect manner during the whole duration of the work, and while remaining thus duly steadied, it may be adjusted in such a manner that the traction on the string is effected along the axis of the corresponding hole in said frame.

With this apparatus, the use of thepunch is unnecessary and, moreover, the gripping of the strings is effected in such a manner that the traction on the strings never exceeds that which is finally required.

'In order to make the different characteristics of this apparatus clearly apparent, as also the method of stringing, a detailed description is given hereafter, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a front elevation of the apparatus with a transverse section through the worktable;

precisely for its ob- Fig. 2' is a plan view of the work-table and of the tension-device;

Fig. 3 is a section on line III:-I-II of Fig. 2;

Fig. 4 isafront view of the device of Fig. 3;

Fig. 5'is'asection onl-ine V-V of Fig. 2;

Fig. 6 is a sectionon line VI-VI of- Fig. 1;

Fig. 7 is a front view of the clamp used for steadying the string during the work;

Fig. 8 is-a side elevation of the device of Fig. 7;

Fig. 9 is a; vertical section: through an inner fixing hook for the racket frame;

l0 is a plan view of the device of Fig. 9;

Fig. 1-1 illustrates the device of Figs. 9 and 10 applied to the racket frame;

Fig. 12 is-a front view with a partial section througha part of the tensioning slide.

According to Figs. 1: and 2, the apparatus comprises mainly three principal parts, namely a work-table forming the supporting device proper for the racket frame, atensioning device and, final-ly e, special clamp for steadying the string which has 11151? been tensioned, thus permitting the placing of the next string.

The work-table com-prises a frame I, the shape of which is like the general shape of a racket frame. This element is mounted on a bottom plate 2,=by means of small-col ns 3, which thus secure a determined fixed distance between the said frame I and the plate 2. The latter is pivotally mounted upon a fixed plated, which is itself supported by the upper table 5 of a frame 6, which isused; moreovenesasupport for the other elements of the machine. The rotary plate 2 may be periodically moved and successively steadied in different positionsfor instance, those in which a'hole in the racket with. the-drawing direction of the tensioning device.- For this purpose, the plate 2 is fitted with holes 1 around its edge, in which may be introduced a stop or hook. 8.,. easily accessible and easily manipulated- The support frame i for the racketalso presents a succession of small holesfl. The latter areintended for the intrs duction of special abutment's displacedduring the stringing work and the main object of which isth afford a firm support at the part or close to the part of the racket frame capable of being deformed. These abutmen'ts are formed by simple small angle irons having a lower stud engaging the aforesaid holes 9, the upright part of these angle irons being traversed by a small threaded r'od ending'with a knob l2, which maybe brought exactly in contact with the outer side of'the' racket frame, whatever may be the shape and the position of the latter. In this frame is in line 10,. which may be way, the same abutments may be used along the whole periphery of the racket frame.

Prior to the stringing work, the racket frame [3 is firmly steadied upon the support I, by means of inner clamps placed respectively within the major and minor axes of the racket frame. These clamps are particularly illustrated in Figs. 3, 4 and 5, and it may be seen that they can be easily displaced and fixed. These clamps are formed by a stud l4, integral with a rod 15 passing through a lower guide IS. The free end of the rod I5 is threaded and engaged by an easily accessible nut l'l. Under these conditions, by screwing or unscrewing the said nut, the stud I4 is moved in one or the other directiom thus freeing or pressing the racket frame.

Preferably, the clamps of the small axis (Figs. 9, 10 and 11) are slidable in four directions, so

that they can be placed exactly intermediatetwo holes of the racket frame, this preventing their displacement during the work. Such displacement would indeed cause the deformation of the frame. Now, such clamps are exactly located between two holes and against the inner face of the frame. A thumb-screw ll keeps the stud against the frame I, whereas a set-screw l1 prevents the device from sliding towards the center of the racket. 1

The work-table proper is completed by two guide frames or bridges, one of which may be arranged in the vertical plane passing through the large axis of the racket frame, whereas the other one may be arranged in the vertical plane of the small axis. These bridges are substantially formed with a guide bar IS, the section of which is preferably a double T, which means that the two lateral faces of this bar present a longitudinal groove. This bar is supported by two small gates l9, simply engaged by the bottom parts of their vertical branches in corresponding holes of the frame I forming the support of the racket. These gates are such that the bar I8 is locatedat a determined distance above the racket frame, which distance is determined by the size of the pressure after.

In fact, these transverse and longitudinal elements are simply intended to be used as a support for the said clamp, while permitting an easy displacement thereof.

Fig. 2 shows diagrammatically in plan, in a sufficiently clear manner, the arrangement of the longitudinal bridge. 7 V r The strings are placed in the ordinary manner, that is to say that theyare passedthrough the holes of the racket frame in the known manner, the main characteristics of the invention relating to the apparatus for and the method of tensioning the strings. 7

Indeed, the tensioning apparatus is constructed in such a manner that each of the strings, whatever may be its position in the racket, is tensioned with a practically constant force. This device is substantially formed with a carrier or slide I9, adapted to be moved by rolling along a guide-way 20, supported by uprights 2|, 22. V

The said guide-way is arranged almostat right angles to the large axis of the racket, when the support of the latter is in its initial position (see Fig. 2). Furthermore, the carrier [9' 'is provided with internal rollers 23, 24, arranged respectively above and underneath the guide-way 20, and these rollers engage the grooves of said guide-way in such a manner that a perfect guiding and a complete steadying of the carrier is clamp described herein secured. The carrier is provided, at the upper side, with a peg 25, for guiding the string, a. bitt a small swinging clamp jaw 26 for clamping and fixing the string, and finally with a fixed jaw 21. The cable 28 is attached to the clamp jaw 26, this cable connecting the carrier to the tensioning device. The swinging jaw of the clamp is, moreover, connected by a helical spring 26, to a fixed abutment formed by an angle iron integral with the carrier, a set-screw 26 affording the adjustment of the spring action. At the end of the return stroke of the carrier, an abutment opens the clamp for permitting the engagement of the string into the clamp. The cable 28 is connected to the end of the swinging arm 29 pivotally mounted, at 32, upon the frame 6 of the apparatus. On this lever 29 is slidably engaged a counterweight 30, the position of which can be adjusted by means of the screw spindle 3|, to be operated by a handle 33. In the bottom part of the frame -6 is mounted a manipulation pedal 34, in bearings 36, and this pedal is connected by a lever system to the end of the swinging arm 29, adjacent to'the cable 28. When the pedal is depressed, the lever system 35 lifts the counterweight 30, so that the cable 28 is loosened and the carrier l9 may freelycome back to its initial position, owing to the fact that it is permanently drawn by a counterweight 39 ending a cable 40, which is connected to the front of the said carrier I9.

When the pedal is depressed by the operator, the latter having passed the string through the corresponding hole of the racket frame, brings the said string around the bitt 25', then between the jaws of the clamp 26 of the carrier I9. The string is furthermore duly guided between two rollers 4! in top of the uprights 2! of the tensioning device. The string being duly fixed to the carrier, the operator releases the pedal 34; the clamp 26 closes up and the carrier l9 starts its course. The counterweight goes down, so that a traction is exerted upon the cable 28, and this cable produces a traction on the carrier IS. The movement of the latter securesthe tensioning of the string which has just been placed, and this tension will be practically constant, because it is determined by the weight of the counterweights 30 and 39.

It is noticed that the tensioning of the string, which is the most diflicult and the weariest operation in the known processes, is thus made independent of the operator.

In order to be able to place the next string, it is necessary to keep under tension the string which has just been placed. For this purpose, use is made of a clamp, also very easy to manipulate. The latter is diagrammatically illustrated in Figs. 7 and 8 of the accompanying drawings.

Such clamp is substantially formed with two jaws 42, 43, mounted upon a common pivot .44, formed in this case by a spindle passing throughout the clamp and ending, at one side, in a tapered point. The latter is intended to become engaged in the corresponding groove of the bar l8 described hereinbefore. Thus will be formed the first steadying point of the said clamp. The second steadying point is formed by an angle iron 45 fixed to one of the jaws and adapted to be supported by the adjacent part of the racket frame.

The bottom edges of the jaws 42 and 43 have indentations or teeth of any shape and sufficiently distanced for permitting the passage of the strings. One of the teeth, the first one 46, for instance, will be of reduced depth with respect to the others, so that it may rest on the corresponding string, this aifording a supplementary steadying point so as to always locate the clamp exactly in the same position. This secures the possibility of clamping all the strings exactly in the same manner. The clamping is effected by approaching the lower part of the jaws 42, 43. This movement is made possible by the swinging of both elements around the common spindle 44. The swinging motion is determined by the spacing of the upper edges of the two jaws, which are provided at this place with an adjustable spring seciu'ing the spacing of the said jaws. Obviously, this manipulation means may be replaced by any other device, such as namely a device having a handle, an elastic pressing device, and the like.

I claim:

In an apparatus for stringing tennis rackets and the like comprising a rotatable supporting frame upon which the racket frame is clamped by internally acting clamps and a tensioning device acting on the string with a predetermined tractive efiort the arrangement of a guiding frame fixed upon the supporting frame, a guide bar integral with said guiding frame located above the racket frame in a vertical plane passing through the major axis of the racket frame and a clamping device mounted on a spindle supported and guided by said guide bar and the racket frame, adapted to hold the string under the tension imparted thereto by the tensioning device during the threading of the next string portion.

ADRIEN RYCKMAN.

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