BE1013793A3 - A device for tensioning pre-strung but untensioned strings in sports rackets - Google Patents

Abstract

Tensioning machines and tensioning techniques for sports rackets. A device consisting of a modified and rotating traction lever mechanism (4) with a built-in tensiometer (3) and string attachment point above the string bed, modified string clamps that are clamped against the racket head (8), modified racket fixing mechanism (2) that only allows clamping to be done from the outside and a modified round string clamp to make it easier to get started. All the work is done from above the string bed, which makes it more comfortable to use. Both new and old tensioning techniques can be used.<IMAGE>

Description

       

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   DEVICE FOR TENSIONING PRE-Woven, NOT CLAIMED
STRING IN SPORT RACKETS
THE TECHNICAL FIELD TO WHICH THE INVENTION CONCERNS
This invention relates to tensioning machines and tensioning techniques used for tensioning, tensioning and re-tensioning of tennis rackets, squash rackets, badminton rackets and other sports rackets.



   RELEVANT STATE OF THE ART WITH HIS ASSESSMENT
Typical sports rackets consist of a racket head with a string bed. The parts of the racket head are: head, heart and handle with handle. They used to be made from natural materials such as wood, but are now made from synthetic composite materials. There are many brands of rackets: Prince °, Yonex Wilson @, Dunlop @, Gamma ° ... and just to name a few.



   The head can take many forms: round, oval or angular. The profile of the racket head used to be flat on the inside of the racket head, near the wooden rackets, but is now mostly bent. These changes in shape and profile (the typical racket heads are now hollow inside) became possible since the use of composite materials for rackets (eg Badminton: graphite fiber rackets held together by resin resins reinforced by titanium fibers). In relation to the stem, the head has also been made much larger lately, resulting in a larger string bed and therefore greater tensioning required. (U. S. Patent No. 3,999,756: tennis racket with altered geometry resulting in a larger head and longer strings, U. S.

   Patent Number 4,531,738 and Number 4,618. 148: racquetball rackets with altered geometry resulting in a larger head and longer strings). The strings of this string bed pass through holes in the racket head. One can have an even or odd number of holes, but they will always be evenly distributed over the total racket head surface. Sometimes the holes are not in the same (string bed) plane, but for now this is the exception rather than the rule. However, it is the rule that the holes are provided with plastic tubes to protect the strings when passing the racket head. These tubes are available separately or on a strip. Because increasingly higher voltages are used and in view of the possible strings of the current clamping machines, reinforcements have sometimes been made on the racket head.

   These are located at those points that must absorb the most voltage. People refer to the different places on the head with the words: top, shoulder points

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 and center point. And one also speaks of that part of the head that is left or right of the stem.



   The heart of the racket is not always present, sometimes the head flows into the handle without leaving an opening in the middle. (U. S. Patent Number 08/279. 837 shows a squash racket geometry that is widely used whose strings extend into the heart of the racket.) The typical handle, handle, does not have to be made of the same material as the racket head. It is important here that as little torque as possible is allowed to occur during the game and also outside it. Regarding the length of the racket, it varies considerably and this depends on the size of the racket head. As already mentioned, rackets with a large head have a relatively smaller handle.



   The typical string bed consists of a string that, wholly or in parts, was woven through the holes of the racket head according to a certain pattern, creating a stringed surface. This also creates a 'sweet spot'.



  It is with that part of the string bed that one can catch non-centered balls / plumes / .... There are many brands of strings on the market: Prince *, Yonex * "Wilson", Dunlop *, Gamma * .... Most brands that produce rackets also make strings.



   Just like with the rackets, there are natural and synthetic strings.



  With the natural there are for example the gut strings. They are very moisture and temperature sensitive and have a great stretching power. The synthetic strings (fi fiberglass, polyester, graphite, etc.) then have fewer problems. They come in many materials and they are usually composed of different fibers. Most strings also have a protective layer, 'coating' from a durable material (eg Silicones) to reduce the wear of the string. There are different string types depending on the purpose: comfort strings, long-life strings, high-speed strings, strings for optimum control or multifunctional strings. This is determined by the technique, the way of playing and the temperament of the player.



   A weaving pattern is created by the holes in the racket head placed at equal distances, the direction in which the string is woven and the way in which crossing strings pass each other. In the most typical string patterns, 16 to 18 longitudinal string pieces relate to 18 to 20 transverse string pieces. The longitudinal ones are parallel to the stem and the transverse perpendicular to the longitudinal one. The parallel, transversal strings pass alternately below and above the previously,

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 parallel longitudinal strings. And no two adjacent transversals pass a longitudinal string in the same way.



   (In fact, the use of the word string is not always correct here. A racket contains a string, whether or not cut into pieces depending on the use.) Between two holes there is a string and not a 'string' as a whole. These two meanings are used interchangeably in the literature: the word "to" can mean both the entire length and a piece. Only the text then clarifies the meaning.) Sometimes the string to be used is divided into 2 parts: one part to use in the longitudinal direction, the other to use in the transversal
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 dividing the direction into strings has consequences for the number of knots to be made at the strings. When using one string as a whole, two knots are made. In the case of the shared string: four knots.



   Reference is made to the positions on the string bed with the words: above the string bed, below the string bed. The underside of the string bed is the side that faces the floor.



   The string bed is not loose in the holes. There is a certain tension on each string that passes through two opposite holes. This voltage is determined in advance and may not exceed a maximum (and minimum) value given by the manufacturer. We use a tensioning machine for this.



   Typical clamping machines consist of a chassis with a plateau and clamping mechanism on top. The racket is fixed on that platform via fixed and / or movable arms. Sometimes one or more fixed string clamps (clamps) are also found. If there are no fixed wire cutters, loose (hand) wire cutters are used. The string is brought to a predetermined tension via the tensioning mechanism. All kinds of supplied accessories (such as the loose clamps) help to stretch the rackets. No distinction is made between devices for tennis, badminton or squash racket only. Well-known brands of tensioning machines are: ATS * EAGNAS * GAMMA * SPORTED PRINCE * EKLETON *.



   General features of these devices are: robustness, stability, design, compactness and comfortable handling. They are sometimes equipped with a foot or tripod, whether or not the height can be adjusted.



  The 360 turnable turntable contains 2 or more, whether or not moving, support arms that support the racket from the outside or pull it from the inside. Typical are the rack supports at the top and heart region of the racket.

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  They prevent shrinkage of the racket due to the high tension force that is put on the longitudinal strings. (For rackets with a larger head, this type of support is an absolute necessity). These points each have a contact point with the convex interior of the racket head made of composite materials. In order to prevent the expansion of the racket in the width, there are also usually movable supports that support the exterior of the racket by means of V-shaped clamping points surrounded with protective material. Typical machines usually have 6 racket clamping points which therefore allow a deformation of the racket during tensioning. Two pull points on top and neck and four externally supported on the racket head on shoulder and hip points. This gives 10 contact surfaces between the device and the racket.

   (These external supports are excluded because they would interfere with the weaving of the strings, but for example with the Progression II Electro from ATS *, man leaves enough space between the clamping point and the racket head to allow each string to pass easily.) Given that the most support points are provided with a protective layer, it is perhaps better to speak of 'contact surfaces'. For the most commonly used string tensions, this is sufficient to prevent damage to the racket. Torsion of the racket in a plane other than the plane of the string bed must be excluded. This way of attaching the racket makes it simple and easy to remove and place the racket.

   Fine-tuning makes it possible to clamp all kinds of racket correctly and to the wall and at the same time not to cover the holes for the strings (in the racket head). That is, after all, a condition: the support points must not hinder the strings. Another advantage of the V-shaped supports is that the racket positions itself, as it were, in a position that allows the use of the fixed clamps. For this reason, a height control is sometimes built in. Either in the fixed tongs or in the support mechanism. Otherwise the fixed clamps can no longer be used, which is not the intention 18. The ideal position of the string bed is therefore also parallel to the turntable.



   Securing the racket in the device takes some time in the typical tensioning machine. There are the vertical control, the height control to keep the string bed horizontal with respect to the base and the exterior and / or interior supports. Although the V-shape of most exterior supports helps to position the racket correctly, it still takes some time.

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   The typical turntable is connected to the chassis by ball bearings. One can find the rail or rails for the fixed snares / clamps on it.



  These allow movement in line with the racket and / or following the shape of the racket head. Their working area consists of the surface of the string bed. They can also be adjusted to the desired string thickness (such as the loose string tongs) and they fix the string relative to the turntable. To prevent slippage of the string in the clamp / tongs, a protective layer of diamond powder is 'coated' on the clamps (As an example of typical stringing machine / clamps, we refer to The Progression II of ATS *).



   The typical tensioning mechanism works mechanically or electrically and is fixedly mounted on the chassis, it cannot rotate like the turntable and the attachment point of the string is not height adjustable. (By which the string to be tightened will make a certain angle in the hole of the racket head to go to the fixing point on the clamping mechanism). The tension is generated by using levers, weights and / or muscle strength or via a motor. And the string is clamped on it between metal parts, with or without a string-protective coating.



  There is a relatively large distance between the racket and the attachment location on the tensioning mechanism (the tensioning mechanism), which means that a long string end is required to bridge it. The electrical method gives an even and constant tensile force on the string. Just like the pincers, the place of attachment is made so that it does not damage the string. The applied tension varies from sport to sport. In tennis, typical forces of 10-41 KG are used, in badminton 4-13 KG and in squash 9-26 KG. This means that it must be possible to regulate the tension. This is done by adjusting the weights used, muscle strength or the electrically generated force. In general, there is also a reading scale, in pounds or KG, to determine how much force the string is pulling.

   Used with weights, the tension force cannot be adjusted while the string is being tensioned. This can sometimes be necessary due to the stretching capacity of a string (eg Gut strings). Adjusting the tension is easiest if it is done electronically. This adjustment is then made in steps of, for example, 500 grams and goes to higher tensions than machines that use weights and / or muscle strength. All these devices are easy to maintain and fairly reliable. They must be given an annual maintenance to calibrate them back.

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   Typical clamping machines are sold with some accessories. A guide, tennis prick or alder, flat nose pliers, elbow pliers, wire cutters, string meter, dynamometer, starting clamp, drills and loose clamps. Regarding the loose tongs that work like the fixed tongs. Only a string is not fixed with respect to the turntable but with respect to another neighboring string. Which increases the chance of slipping. Even though the tongs were provided with a special coating against slipping. The tennis pin, alder, nippers and flat nose pliers serve to pierce a second string through the same hole and the elbow tongs are used if the string end to be pulled is too short to reach the tensioning mechanism. One then uses this special pair of pliers.

   The starting clamp is a special clamp for clamping the first, transversal string when working with two strings for the two directions. The bores are used to remove old tubings. Dynamometer and string meter help to check and measure the tension on strings. Finally, there is the tension guide that, among other things, gives the maximum and minimum string tension that is recommended by the manufacturer when tensioning. It also contains how to string your own specific racket. As well as other interesting data that may be of interest.



   Typical stringing methods work either with the full string or with two parts. The strings themselves can be divided into three phases: the preparation, the stretching itself and the evaluation afterwards.



   The preparation starts with checking the condition of the material. Racket, string and tensioning machine must be in optimum condition.



  And a few decisions must also be made. The racket can be damaged, cracked or broken. It is then best to inform the owner.



  Not when the tubings are worn out, just replace them with. And to check racket deformation, it is best to first make a copy of the racket, or to accurately mark the outline of the racket on a piece of paper. With regard to the strings, we need to check a number of things when removing the old strings. The number of longitudinal and transverse strings must be noted. (Or be looked up in the guide). It is checked which holes are skipped for the transverse strings. Also as part of the check, the current tension on the strings is measured with the string meter. And there is also careful attention to where the strings were tied and how many knots there are. Then the strings are cut from the racket.

   This happens spirally to the outside and

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 starting with the most centrally located longitudinal and transverse strings. This is to prevent the racket head from being loaded incorrectly and thus being damaged. Regarding the tensioning machine, it must be calibrated annually.



  And they are adjusted to the tension to be achieved. (You can read the maximum and minimum value of the new string in the spanguide guide) And the loose and / or fixed string tongs to be used are tested for their clamping strength. If not, we will adjust these until they are tight and firm. You will also check in the safety guide where the starting loop (the first, longitudinal loop woven into the racket) will have to be. That can be at the top or at the heart. Gut strings will be kept at the right temperature and humidity and carefully unwrapped.



  They will also have to be initially stretched before use, due to their high stretching power. And you will have to make a number of decisions: Will you work with 1 or 2 string pieces, which tension will you use, which weaving pattern, ... Then you will finally be ready to attach the racket to the device. The (pull) support arms (top and heart) are placed so that they just touch the inside of the racket. The movable, external side supports are turned against the racket and the racket is secured by means of fine adjustment. It is checked for a while whether the fixed string tongs are at the correct height (the height of the string bed) and we are ready to weave the first, longitudinal starting loop into the racket.



   The typical clamping starts with fixing the turntable.



  Racket heads with two, six or ten holes in the heart receive a starting loop in the heart. Racket heads with zero, four, eight, twelve holes in the heart get their starting loop at the top of the racket head. (The starting loop is made by inserting the string into a first hole, from the outside to the inside. Then the string goes into the opposite hole of the racket head, from the inside to the outside. We then take the next free hole next to it and turn in an analogous way A typical starting loop is thus the two most centrally located strings and uses four holes.) Regarding the string, the starting loop is not always nicely in the middle of the string length to be used.



  The top of the starting loop comes to 2, 9 M from the end in case the string is not divided. In the other case one can take the center of the string to be used. Once the loop is woven in, turn the turntable so that the free ends of the loop lie in the direction of the clamping mechanism. And we block the turntable in that position. We can now start immediately with the fixed pliers. We clamp one of the strings as close as possible to the inside of the racket head

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 racket fixing mechanism may get in the way here). The other end is clamped in the tensioning mechanism. And the string is tensioned with a preselected tension force. (By placing a mark on the string, we check whether the string clamps are properly clamped and the strings are not sliding).

   It is then ideal to tighten the string in the plane in which the string bed is also located. That is not possible, so this is approached as much as possible. Next, we place the second fixed string tongs next to the first, on the not yet clamped string, also as close as possible to the same inside of the racket head (Hart or top region). It may be that the first clamp hinders the second one during placement and cannot be placed next to each other. Anyway, this is the start when working with two fixed string clamps. The principle is the same with regard to the loose clamps now, only we clamp a string with respect to a neighboring string and not with respect to the turntable (VB Delrin hand clamps) The point of attachment is now another, adjacent string. This means that we have to slightly expand the starting loop.

   The string ends must therefore pass another hole, the next free one is therefore utilized and a total of 6 holes are now in use. As a result, the ends now go in the other direction compared to the starting loop at the fixed terminals. We therefore have to turn the turntable 180 to get the ends in the direction of the clamping mechanism. (This increases the distance between the racket head and the clamping mechanism.) At this time, it is possible to clamp the free end with a loose pair of pincers on one leg of the starting loop, close to the racket head. And after tensioning, the other end on the other leg of the starting loop, just next to the first clamp and as close to the racket head as possible.

   Analogous to working with the fixed string tongs, therefore, only one string is clamped relative to another string and not a string relative to the turntable. In both cases, with the fixed and loose string clamps, the clamps are used via the underside of the string bed. Among other reasons, there is sufficient space left between the turntable and the string bed. (Another reason is that this allows easy weaving of the transverse strings, but more on that later.) After the first two centrally located 'strings' have been tensioned, we finish the other holes, taking into account which holes should not be occupied. for the longitudinal segment. We first continue with the shortest string end (The 2, 9 M side). And pass through the racket head through the next hole.

   The turntable is turned 180 "and

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 the end is fixed and clamped in the clamping mechanism. The last placed sniper is now shifted / moved to the other inside of the racket head to clamp the string. (We note here that the string is clamped between the string tongs and the tensioning mechanism. The string tongs are anchored with respect to the turntable or the adjacent string and are wall-tight). We work alternately 1 string left and right of the stem until we have to make a knot or change direction (longitudinal to transversal). Sometimes we then immediately work with the string to create the transversals. At the place where the angle is made, the string is then loaded a little more at its turn in the racket head.

   Some manufacturers, however, demand that one should begin to stretch the top or bottom of the racket head. That means that if it doesn't work out nicely, one must in any case tie a knot in order to continue with the second piece. A special, stronger start button is then laid for the transversals and the entire surface is worked from top to heart or from heart to top. To end with a normal knot again. As already mentioned with the weaving patterns, the transversal strings are woven through the longitudinal one, which results in more resistance when tensioning the strings. The thinner the wire, the smaller the resistance.

   However, caution should be exercised when weaving, as the 'coating' of the strings should not be damaged. Care must also be taken when placing knots, that is where most of the accessories are used: the elisions, punctures, Crushing of strings in the racket head, stringing of a string in a knot and damage to the 'eoating' the tools limit the life of a string. The danger for this is real as it is not always convenient to tie a knot through a hole in the racket head that has not yet been used. Sometimes two strings have to pass through a hole. That is why sometimes larger holes have been made in the racket head, but where it is not, one has to use the tools to pull two strings through a rather small hole.

   Three strings in a hole in the racket head may never occur.



   During the evaluation one will check whether one has made weaving errors, one will do this while one is stretching, but also afterwards because one then has a general overview of the weaving pattern. Furthermore, the string meter checks the tension in the middle of the different longitudinal strings. (Sticky fabrics on the strings tend to take the measurements

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 influence.) Measuring the strings can already lead to a loss of voltage, so one must consider whether knowing the advantage of the tension outweighs the possible voltage loss that is caused by the measurement. Just like in the beginning, the shape of a racket head is again drawn on a piece of paper. The racket must not be too distorted and must approach the shape of the unparalleled racket.

   The check of the shape of the racket head and string tension is repeated after the first turns. Loss of tension may indicate bad knots, strongly extending strings, cracked racket, etc. During the first turns, the strings may move somewhat in accordance with the tension and impact force applied to them, the friction of the strings in the racket head or the deformation. of the racket head during the game, but this must remain within acceptable limits. With a well-strung racket, each half of the longitudinal strings has a proportional tension and there is a relative, even distribution of tension across the string plane. It is difficult to always get the same result with the same string type and tension.

   To make correct comparisons and results possible, the manufacturers therefore recommend keeping a log of the savings.



   Typical causes of damage to the racket head are the following: errors in tensioning the racket, placing the racket in the tensioning device or incorrect manipulation during play. Errors in tensioning arise, for example, from a disproportionate distribution of the tension in the savings bed. Mistakes when placing a racket in the racket device can be too hard clamping the fixed and movable support arms against the racket head. And under wrong manipulation, hitting the racket falls against the wall or ground. The lighter rackets, such as the badminton graphite rackets in particular, break quickly if not handled appropriately.



   Typical causes of damage to the strings are due to the strings, the racket, the tensioning device and the accessories used. For example, the string may break at the height of the racket head.



  As a result of missing or damaged tubings, too much tension, too tight knots, the flattening of the strings in the holes, a damaged 'coating', etc. .... But problems can also occur at the height of the snares . When weaving, care must also be taken not to damage the 'coating' of the string. Without the protective layer

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 the string a lot more fragile. And it is at the weakest point that the string will break. In theory, a string could also break through age, because the elasticity has disappeared. But in practice this is not common, except for purely recreational players or beginners. It is important to keep the natural strings at the right temperature and humidity as much as possible.

   For the transport of rackets one can have special 'thermobags' that protect them against environmental influences.



   It is in line with expectations that in the future rackets will be made from new composite materials. That they will evolve in terms of form and profile. The tensioning machines will also evolve with this trend. They will have to provide the required tension and be able to use the new racket models. The stringing method will run in parallel with this. The machines set their limitations with regard to the method of stringing. However, they will have to be so flexible that any type of stringing should be possible without damaging the material. Finally, they will be simple, safe and easy to operate and allow fast strings.



   Remark: It would be ideal if the weaving and tensioning of the strings could be done in two separate phases and not together as is the case now. The existing clamping machines are not designed for this, due to the height of the string bed relative to the turntable, the clamping positions, the distance to the clamping mechanism, the non-rotatable clamping block, the position and nature of the supports, the obligation below and above the string bed, the requirement to be level with the string bed in function of the fixed string clamps, the strong emphasis on clamping the longitudinal strings first and then weaving and clamping the transversals, etc. -. They based themselves on common basic conditions and therefore had the same difficulties: a. The beginning of strings is not easy.

   They all give a similar result and never guarantee that the proposed tension is actually achieved. Apparently there is always some voltage loss due to string, racket or stringing device.



   EXPLANATION OF THE INVENTION
A device for tensioning pre-woven, non-stretched strings in sports rackets. It consists of a rotatable racket fixing mechanism with exclusively exterior, wing-nut-shaped supports that are infinitely adjustable, a rotatable trigger-lever mechanism with a belt-moving element for string attachment for

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 continuously measurable clamping of the strings and three types of continuously adjustable string clamps of which two types with fixation of a string relative to the inside of the racket head and a last type that clamps two or more adjacent strings from the bottom and top of the string bed and so towards the strings.

   The invention encompasses the entirety of these elements (and not each of them separately) which, in their totality, make it possible to stretch already woven and not yet stretched rackets simply, safely and easily. The device, as further proposed here, can be produced in most countries.



   Among the general characteristics of this device, we can mention, among other things: the robustness and stability of the design, the minimum of maintenance due to the simplicity of the component parts, the annual calibration as with conventional models where in this device the friction in the racket frame is checked during calibration. included, the uniform principle of machine construction that is easily adaptable to the different sport types (tennis, squash, racket ball and badminton), the possibility to continue working on one side of the string bed (the top) during the entire clamping process, the possibility to work with a hand puller with regard to the smaller voltages (One simply disconnects the trigger from the lever),

   the possibility to temporarily attach loose and unused strings to hooks in the turntable so that they do not interfere with the tensioning of other strings, the possibility to apply all existing and also new strings, the possibility to tension strings with this machine as would be done with a conventional machine, the possibility of selling the concept as a kit, the possibility of easy use by children and women and the elderly, the possibility to choose the most comfortable position (standing, sitting) for strings, the possibility to optimally and continuously check the tension force during tensioning, the complete freedom with regard to used tension force per string because it does not have to be adjusted once and for the entire duration of the tension (Within the limits of what the used spring can handle)

   and the possibility of developing a table model (in which case no machine foot is used and the base plate is clamped with table clamps).



   The base of the device is formed by a base plate, four legs and a foot plate with a foot board attached to it. On the base plate there is a turntable for racket fixing and the clamping mechanism around the

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 tensioning the strings (trigger-lever mechanism.) The turntable is connected to the base plate by means of a pin with roundel around it.



  This allows easy turning of the table.



   The rotatable racket fixing mechanism consists of a 3600 rotatable turntable with 6 separate fixing blocks on it, 3 on the left and 3 on the right side of the racket. (With the 0 point at the top of the racket head rotating in a clockwise direction, we find the ideal positions of the
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 support points at 400, 900, 140, 220, and 320). They are positioned at such a distance from the center of the turntable that any type of racket fits in between. An additional support was placed between the blocks at 900 and 270 (a metal bolt or other strong material) to prevent lateral distortion of the racket at the points that will have to handle the most tension.

   The fixing block consists of a (wooden) cylinder placed perpendicular to the turntable through which, parallel to the turntable and a short distance from its top, a hole was drilled for a bolt whose center crosses the cylinders. Attached to this bolt is a wing-shaped element (wing nut with protective plastic on the wings) in which the racket will rest. A nut on the bolt is tightened against the fixing block to secure the racket. This can be done at any desired distance, insofar as the length of the bolt permits the appropriate support, and of course for each support separately. It is reliable, easy and safe and the racket is sufficiently secure to hold the first strings. The supports allow you to always reach all the holes in the racket head.

   Each tightened string will also provide additional pressure on the support points (especially the longitudinal strings provide this) and it will anchor the racket more firmly.



  Racket deformation can only occur inwards, which is not a problem because it was provided and developed for absorbing such forces. The racket is therefore clamped by the forces that were generated during the strings and the clamping is directly proportional to that. In essence, the time required to fasten a racket is the time it takes to tighten the 6 nuts against the cylinders of the fixing points. No further adjustment is required, neither in height nor in width. And the string bed does not have to be level. It should just be possible to still tighten the strings with the trigger. This leaves room for future developments in the field of rackets.

   And so there is a lot of time savings here compared to the conventional machines, and

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   this in addition to the existing time savings that one has to do first by weaving the string bed separately. What has not yet been stated and yet it is necessary that between the fixing blocks, in the turntable, holes were drilled corresponding to holes in the base plate. They make it possible to fix the turntable in any desired position with respect to the tensioning mechanism via a pin in order to bring the strings to be tensioned in line with it.



  The trigger-lever mechanism in itself consists of trigger and lever. The tractor is made up of 2 telescopic sliding tubes with a spring brought to basic tension (eg 15 KG for tennis, 6 KG for badminton and 6 KG for squash). The basic voltage is equal to the minimum voltage used on the tensioning machine and prevents the lever from having to be moved too far to reach a voltage. Each end of the spring in the trigger attaches itself to 1 tube via a transversely positioned cylinder inside. The two ends of the spring are thus coupled to the two tubes. By pulling the two tubes, the spring will tighten. This is the basic mechanism of the trigger lever.



  The trigger is attached to a side arm of the lever. This lever is in turn mounted on the base plate of the device and can rotate 3600 to bring the trigger in line with the string to be tensioned as much as possible. The length of the lever determines the ease with which this happens. Optionally, an extendable element could be provided here to make the lever longer or shorter. The trigger can also rotate, and this in a plane that is perpendicular to the base plate, but never farther than a bar on the lever arm that must prevent the trigger from falling outside the work surface. Now pull (or push) the handle of the lever then a tube of the trigger moves.

   This is connected via the spring to the second tube on which a T-shaped piece is mounted that is covered with a rubber (or other material with anti-slip property) grooved layer. This serves to fix the string coming from the racket hole on the inside of the racket. (One can approach this piece of string by moving the lever to the opposite inside of the racket head and thus reducing the distance between the inside of the racket head and the trigger head). The force exerted on the handle will pull out the spring and tension the string. The applied force is such that no shocks occur. Sometimes it is necessary, as already mentioned, the entire trigger mechanism

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 what to turn to place the trigger nicely opposite the inside of the racket head.

   By attaching the string on one side to the trigger head and the other side to the lever arm you can therefore tension the spring (and also the string). The question remains how much tension that is and how to connect the string to the trigger. To achieve the desired voltage, man uses a reading scale that is mounted on the outer trigger tube. Via a slot in it, and a pin that was mounted on the inner tube, it is possible to read what the tension force used is for tensioning the string. The indication can be displayed in pounds and KG at the same time. left and right of the slot. This pin also indirectly determines the maximum voltage that can be used with the trigger. Namely, it cannot move beyond the starting point and end point of the slot.

   (The maximum voltage differs from Sport to sport: eg Tennis 40 kg, badminton 13 kg and squash 26 kg are real maxima today). Connecting the anchor wire or belt end to the tractor is very easy. We know that this is a T-shaped piece with the neck in the direction of the lever arm and the side pieces are parallel to the string bed.



  The string, coming from a hole in the racket head, is brought under a side piece (the closest side piece) and once rotated around it until it comes out in line with itself again. Then one passes with the string over the neck of the T-piece at the top. Again the string passes under the T-piece and one passes forwards between the already stretched piece of that string and the underside of the T-piece. Eventually one comes back in line with the same string when one pulls the string in the direction of the lever arm. The string is positioned in such a way that when the trigger spring is tensioned, it pulls itself into the anti-slip layer without damage.

   If this does not happen, then no tension can be applied to the string. in this way the connection works self-regulating.



   The three types of string clamps fulfill the task of fixed and loose clamps with the typical models. For easy working, one has two pointed and two rounded clamps for clamping a string and a round clamp for clamping two or more strings. The pointed and rounded string clamps consist of two elongated, rectangular metal plates with filed (2 mm thick, 10 cm long and 22 mm wide) sides that are surrounded by somewhat wider (approximately 3 mm) wooden plates that are glued to the metal plates confirmed. They are held together by 2 bolts (thickness 4 to 6 mm) and 2 nuts that can be tightened or loosened depending on the

  <Desc / Clms Page number 16>

 string width.

   (A fan section prevents the nut from turning.) They are at a certain distance from the longitudinal ends and half the width of the plates. The plates do not touch each other, but are separated from each other by a roundle with a width of 0.7 mm. This roundel prevents the strings from being crushed and keeps the metal plates parallel. The belt clips have a round or pointed shape according to their function. The clamps are slid over the string and it slides between the metal plates on the pointed or rounded side. In order to be able to press the plates together, two more washers were placed on the bolt at the top of the clamp between nut, bolt head and wooden plates.

   The wide, rounded ends have an extra wide, continuous clamping surface and are used in 99% of the cases for clamping strings. The pointed tips are used in case the round clamps cannot be used. This is usually at the end of the string and when clamping transversal strings. The string clamps are placed against the inside of the racket head. The wooden (wood in our example) plates that are somewhat larger than the metal prevent damage to the racket head and tubings and they determine the distance at which the clamp must be placed in relation to the racket head. In terms of shape, they follow the shape of the metal plates. Finally, there is the round belt clip for clamping two strings at the same time. This should only be used if the clamping is started.

   This is because the two most centrally located, longitudinal string pieces are clamped at the same time and, upon returning the string pieces, they are clamped through the following holes on the inside of the racket head with the round l-string clamps. Then, in order to prevent any sliding of the string, the two most centrally located longitudinal strings are clamped relative to each other on the inside of the racket head at the height of the top of the starting loop. And this through the round 2-string clamp. It consists of two wing nuts, a bolt and two washers between which one strings the strings. This is an additional tool and it assures us that the string does not slide when strings. This last clamp can also be used for tying off, but this is not necessary.



   Regarding the racking of rackets themselves, as already mentioned, one can work as usual. The preparation method, the clamping itself and the evaluation afterwards run analogously to what has already been described and

  <Desc / Clms Page number 17>

 conventional is That is not repeated here. However, the deviations from the current way of working are explained here briefly.



   ADVANTAGES OF THE MACHINE AND CUSTOMIZED METHOD
The first difference is therefore the clamping or fixing of the racket on the device. It is sufficient to place six support points placed externally to the racket as described above (simply connect nicely to the racket head). No further fine-tuning is required because the racket sets itself more tightly and tightly during the strings themselves. These supports do not hinder the strings at any time because the weaving of the string bed has already taken place. They allow a certain movement of the racket head, which is not the intention with conventional tensioning machines. And they prevent distortion in other directions than in the direction of the string bed. This distortion of a few millimeters helps to correct any possible voltage loss afterwards due to the clamping method or the device itself.

   As well as to compensate for the loss of voltage during the first turns and to test the string voltages with the string meter. There is no need for internal supports at 0 and 1800 (with 00 as the tip of the racket head). With conventional machines, there is a real chance that the racket head will be made longer, in line with the handle. This is not possible with this machine. With this machine it is possible that after racking and removing the racket from the device, the racket head is a little bit (Approximately 1 mm) smaller in line with the handle compared to the unstressed condition. This helps to keep the string bed at the appropriate tension. Conventional machines sometimes have the problem that the string bed relaxes faster than expected.

   This may, for example, be due to the deformation that conventional machines allow in the longitudinal direction, as explained above.



   A second difference is an alternative to the start of the stretching. In the longitudinal and transversal plane, one can start by tightening start loops centrally located in the string bed, and thus tensioning the remaining strings alternately with respect to the central loop and with one string at a time. This ensures perfect voltage distribution in both directions and the racket is not loaded asymmetrically in any direction. This does happen if you start clamping under or above, left or right, such as when there is no end node at the transition to the transversal direction. The tensioning of that starting loop is done by tightening the 2 strings at the same time

  <Desc / Clms Page number 18>

 because this is also the mechanism by which the racket is pushed firmly against the fixing blocks.

   With the use of central starting loops in both directions, the use of the special starting buttons is avoided. It is never really good to pull a knot when tightening, nor to pull it directly onto a clamp. With conventional machines, this can lead to voltage loss due to slipping or string damage.



   A third difference is the clamping itself. Where in a conventional machine the attachment of the strings to the clamping mechanism takes place at a relatively large distance from the racket head, this is now done as well as against the inside of the racket head. Namely, it is possible to move the trigger head towards it in a simple manner by turning the lever arm and the trigger section. However, this clamping does not only differ from conventional machines at this point. The attachment of the string to the trigger is also different from conventional. The typical conventional machines here use a kind of clamping jaws, whether or not covered with diamond powder or other material. This is not necessary with this machine because of the anti-slip coating on the tractor head and the special way of fixing the strings.

   By incorporating the reading mechanism in the trigger, one immediately catches all voltage variations that the clamping causes, and one counts the friction that the string has in the racket head. Finally, the tractor follows the ideal line between the hole and the lever point, as close as possible to the string bed. The angle formed is always the ideal angle not to damage the string on the racket head. That is why it is also possible to rotate the entire trigger lever mechanism. And while we are talking about that leverage, it makes it possible to use large clamping forces with a minimum of effort. Clamping forces that can then be read in KG and pounds at the same time, if these distributions are placed next to the slot of the outer trigger tube.

   If for some reason the string is not properly secured to the trigger, then the desired tension cannot be achieved. The entire aanano system is simple, maintenance-friendly and easy. Where conventional manners always require an adjustment of a tension force, this can be omitted from this machine. The user determines at any time what tension a string gets, and he does not have to set anything in advance. The trigger is immediately ready for use.



   A fourth difference is the new clamps or pliers. They are adjustable just like the conventional ones, but are not covered with a coating

  <Desc / Clms Page number 19>

 inside. With the new method, the clamps only serve to prevent the string from being pulled back, they yield in the direction of pulling because they are not hindered there by the racket head. The advantage of these clamps is that they are very manageable and very easy to control, that they do not take up a lot of space, block the string perfectly, are not impeded by the racket fixing mechanism during placement and can be used along the top of the string bed which is a lot easier than having to apply them to the string bed from the bottom. When stretching is easy to start stretching is always a problem.



  The starting loop is the correct way, but tensioning one leg separately from the starting loop is not the best way to start the tensioning. It is better to tighten the two legs at the same time, use a 2-string clamp with a wide clamping surface as explained, and separate the legs again to the correct tension.



  The result is that the racket head nicely leans into the supports and the middle strings are stressed better due to the deformation of the racket head inwards. Of course, the clamps were made in such a way that they damage neither racket head nor racket and have a minimal impact. Certainly no more than what conventional snares do. The conventional string clamps do not work with a continuous clamping surface, but have a tooth-shaped structure. And as for the conventional 2-string clamps, they work perpendicular to the string bed surface and are placed underneath. With the new string method, you always keep an overview of the racket to be strung, because you always work on top of the string bed. 3 to 5 string clamps are provided with the device.

   They are simple and easy to produce and so 5 is a reasonable number.



  This allows double clamping when stringing. If one makes the mistake that a string clamp has not been placed correctly, the clamp placed on the previous string compensates for this and not all work has been lost. It can hardly go wrong this way.



   A fifth and fairly important difference with the conventional way of working is of course that the weaving of the strings did not happen on the machine.



  You first weave the strings (without tying them in) and only then will you put the racket in the device to tension the strings. Working with two starting loops and two string pieces, longitudinal and transversal, it is easiest to work if you first place the transversals and then weave the longitudinal strings. Then one automatically notices which holes are intended for the tranaversal strings. (However, sometimes the manufacturer demands that

  <Desc / Clms Page number 20>

 one starts to stretch the transversals at the bottom or top of the racket head. In that case we still work with the central loop, but when we first stretch we work from the center down or at the top.) Of course the strings are not tightly woven in, they allow some leeway to make the clamping possible. A lot does not have to be as already explained.

   In principle, it is possible to use the same string for re-stringing a racket, so this clearly shows that not much play is needed on the string. Once the racket is woven, it is easy to check whether one has made any weaving errors. Every error corrected here gives a serious gain in time compared to conventional machines where weaving goes hand in hand with tensioning. Of course, the user can decide for himself how he or she weaves the racket: conventional, as suggested above or in a self-chosen way. However, it is advisable to work with the start loops because the string lengths to be passed through are then the shortest, the string is loaded the least and the tension distribution on the string bed will be better. (Sometimes the racket manufacturer will exclude this: eg with pear-shaped rackets).

   However, it is the user who chooses what to do with this device, and experimenting with tensions, rackets and strings are also a goal of this machine. The limitations it imposes are quite minimal, again due to the simplicity of the design.



   This is the essence of the invention. Furthermore, the base is stabilized by a footrest with a footboard. The full body weight on the footboard prevents the device from moving.



  The footboard is connected to the footplate with two or more hinges and can be swiveled in when storing the machine. Rubber (or other durable material with the same properties) non-slip soles on the base plate prevent any sliding of the whole. A support between two of the four legs of the device reduces its longitudinal movements. The four legs were placed on the longitudinal axis and width axis of the foot plate, two on each axis and against the edge of the foot plate.



    Loss of tension as a result of the way of stringing is virtually impossible with this device because the racket head friction is also measured when clamped. The belt clips do not allow the belt to slide. And when the string slides over the rubber layer, it is not possible to tension them. Where traditional tensioning machines cannot guarantee a preselected tensioning force in the strings, this can happen here.

  <Desc / Clms Page number 21>

 



  And there is no restriction on the type of string, string type or type of racket. There is no need to leave space under the racket, no diamond powder is needed in the string clamps and deformation of the racket can only go inwards.



   The racket is slightly pulled lengthwise (Approximately one millimeter), which gives a tensioning effect afterwards.



   This prototype was developed with parts for sale in every DIY store. It requires no exceptional muscle power when operating and it is practical and easy to use. It is possible to develop a table model of this and one can sit or work standing. It lends itself perfectly to mass production.



   The concept of strings before weaving and then weaving makes this type of work a lot easier. A mistake made during weaving is noticed before the tensioning starts. Of course you have to leave a few loops during weaving to make it possible to tighten, but that is no problem at all. This concept gives a new perspective on strings and tensioning machines, and that is what the inventors patent is all about.



   BRIEF DESCRIPTION OF THE DRAWINGS.



   FIG. 1 is a schematic side view of the new machine;
FIG. 2 is an enlarged plan view of the turntable on which, by way of example, a racket with an oval racket head has been clamped;
FIG. 3 is a schematic plan view of the base plate on which the turntable and the lever-trigger mechanism are mounted. It shows the position of the holes in the base plate that serve to fix the turntable with a pin.



   FIG. 4 is an enlarged plan view of the scale of the tractor of FIG. 5, this will differ according to the spring used. A scale distribution of 6 to 25 Kg and a distribution of 16 to 35 Kg has been proposed;
FIG. 5 is an enlarged side view of the trigger which forms part of the clamping mechanism;
FIG. 6 is an enlarged side view of the clamping mechanism indicating the directions of movement of the various components;
FIG. 7 is an enlarged rear view of the clamping mechanism indicating the possibility of rotation of the clamping mechanism;

  <Desc / Clms Page number 22>

 
FIG. 8 is an enlarged side view and plan view of the pointed 1-string clamp indicating where the string should be located during clamping. It also indicates what the round 1-string clamp looks like.



   FIG. 9 is an enlarged plan view and side view of the round 2-string clamp indicating where the 2 strings should be located during clamping;
FIG. 10 and 11 are enlarged plan views of the tensioning machine indicating the way in which the first 2 longitudinal strings are tensioned with the trigger lever. Start and end of the promotion are displayed.



   FIG. 12 is a top plan detail of a racket head with indication of only the first 2 tense longitudinal strings and the associated clamping placements.



   FIG. 1 to FIG. 9 show an example of the new clamping machine with corresponding pointed L-belt clamp with a broadly connected clamping surface (8) and the double, round 2-belt clamp (Wood and metal) (9). The round 1-string clamp is analogous to the pointed string clamp except that the pointed end is rounded off half the distance from the pointed end and first bolt.



   BRIEF DESCRIPTION OF AT LEAST AN EMBODIMENT OF THE INVENTION (The materials used are given by way of example only and are indicated in brackets with the indicated drawing elements. Other materials with similar characteristics, which are necessary for the correct operation of the machine, can be used) used)
This clamping machine differs from the existing models by the use of six fixation blocks (2) located externally to the racket (Wood, metal and plastic), the absence of interior fixation points, the loose clamps already mentioned in the description of the invention and a trigger lever mechanism consisting of a trigger (3) (metal and rubber) and lever structure (4) (metal) whereby it is possible to read the used tensioning force from the tractor (23).



   Holes (1) have been drilled in the turntable in a regular manner between the fixing blocks and small hooks (61) have been fitted to temporarily fix loose strings. Rotating around the center of the turntable (19), each of these holes passes through a correspondingly arranged series of holes (17) on the base plate (20) (Wood). By placing a pin (Metal) (10), the turntable is fixed in any desired position with respect to this base plate. This allows any (string) hole

  <Desc / Clms Page number 23>

 to bring the racket head of the racket to be stretched in line with the trigger, by turning the turntable and placing the pin if the position is reached. The smooth turning of the turntable is ensured by a circle between the turntable and the base plate (metal).

   An additional fine-tuning of this tensioning device can also be obtained by rotating the entire trigger-lever mechanism around an axis (11) that is mounted in the base plate.



   The fixing blocks consist of a cylinder (Wood) (25) that is mounted perpendicular to the base plate. A hole is drilled in it parallel to the base plate whose longitudinal axis of the cylinder formed by this hole is perpendicular to the racket head. A long bolt (Metal) protrudes through this hole with a wing nut (Metal) attached at the end. Its wings are surrounded with a protective layer (Plastic). Between wing nut and cylinder there is also a nut (Metal) (7) that can be turned against the cylinder to determine the minimum distance of the wing nut from the cylinder. There is no second nut on the other side that would prevent movement of the wing nut in the other sense.

   Six of these fixing blocks placed at the positions shown in FIG. 2, allow the racket to be fixed in height just below the point of rotation (28) of the trigger, with the string bed parallel or approximately parallel to the base plate. (Parallel placement is not an absolute requirement for the new method since there are no fixed clamps on the base plate. There is therefore no need to level the string bed.). The rotation point of the tractor is high enough for the wing nuts to pass under the tractor when the base plate is turned. Finally, with regard to the fixing blocks, it can also be said that the blocks at 90 and 2700 (with 0 as the racket head top) are connected to each other by a rod (18) (Metal) with two nuts. These nuts are turned against the outside of the fixing blocks.

   (Unlike the other nuts associated with the fixing blocks). The purpose of this construction is to further reinforce the points that must handle the highest stress and to prevent any external distortion of the racket at this point.



   The lever-trigger mechanism therefore consists of the trigger and the lever arm with T-shaped handle (30). The lever arm can rotate along its vertical axis (11), causing the trigger to rotate 360, but this arm has two other options for movement. The first is the possibility of rotation offered to the tractor so that it can be lowered and raised

  <Desc / Clms Page number 24>

 and a second possibility of movement has a point of attachment in the base of the mechanism (29). This allows the arm to move in a plane parallel to that of the tractor. This movement is necessary for tensioning a string. These movements are of course limited. The trigger will never rotate beyond the arm if it is removed from the racket. This is prevented by the trigger stop element (31).

   In principle, this is nothing more than a tube placed perpendicular to the lever arm on the side of the tractor and in a plane perpendicular to its plane of movement, which prevents the tractor from falling over outside the working field where it applies. The movement of the lever arm is limited by the base plate and the turntable. The connection between the tractor tube and the lever arm is made via an intermediate piece (32) (Metal). This is a T-shaped piece of tube (Metal) mounted on the lever arm and over which a second T-shaped tube is slid. The trigger tube is slid into one part of the T-shape, the other part slides over the side arm of the lever. Where the connection to the lever is fixed, the other connection to that piece is not. This allows rotation, which is shown in FIG. 6 shows.

   FIG. 6 and 7 all movements of the lever-trigger mechanism were repeated again. FIG. 5 then deals in more detail with the pulling mechanism itself. The two telescopic tubes (33,34) (Metal), as well as the spring (35) (Metal), the cylinders on which the spring grips (36, 37) (Metal) and which are connected to the tubes, are clearly visible. , the reading pin 38 (Metal) and the reading scales (26,27) (Grooved in metal) and the belt attachment point with anti-slip layer (39). The anti-slip layer is glued onto a T-shaped metal piece that was mounted over the trigger tube. It will be clear that the spring can extend along the longitudinal axis. The tubes do not allow another movement because they move at a minimum distance from each other.

   A short guide tube (55) ensures that the two tubes connect seamlessly, even when using high tensioning force. It is attached to the outer tube of the trigger and prevents lateral movements at that point of the trigger.



   The base of the device consists of a base plate (Wood), 4 legs, a base plate (54) (Wood) and a folding footboard (14) (Wood). (With a table model, this full foot can be replaced by a base plate and table clamps). Two legs are connected (parallel to the tractor direction) in the same way as the fixing blocks on 900 and 2700 are connected (24) (Metal). This is to prevent movement of the foot in that direction

  <Desc / Clms Page number 25>

 to go. The base plate has anti-slip feet (15) (Rubber) for the same reason. The folding footboard is also provided with this, as well as with two hinges (22) (Metal) with which it is connected to the foot plate. The body weight of the recipient gives the device an extra stable basis.



   FIG. 8 and 9 show the movement and the construction of the clamps. The elongated clamps, pointed and rounded (52) (Wood and metal), are provided with plates (40) (Metal) with filed corners (46) between which a roundel (43) was placed on the front nut. The somewhat larger plates (41) (Wood) protect the racket head of the racket to be strung (shown diagrammatically (51)). Two bolts (48.42) (Metal) and nuts (a. A. (44)) (Metal) hold these two materials together, separated in the middle by a circle (43). A fan section (47) (Metal) allows the bolt to be tightened without moving the nut on the other side of the belt clamp.



  Two larger washers (49) distribute the force exerted on the outer plates so as not to damage them and also to retain the clamping force. Tensioning these nuts determines the clamping force of the clamps. The string (45) must not be crushed or damaged. In addition to the two 1-belt clamps (round and pointed), the round 2-belt clamps (9) are also used (Detail Fig. 9). They consist of 2 round pieces (50) (Metal), a bolt (Metal) and two wing nuts (Metal) (12) that move the round pieces together when moving (see Fig. 9) and thus clamp the strings. This is a large clamping surface, so the string is not hit more than with the conventional clamping mechanisms.



   FIG. 10, 11 and 12 describe the method at the start of the clamping. The belt loop (56) is attached to the trigger head, which is first brought as close as possible to the racket head so that the reading scale on the trigger shows the minimum tension (57). The two central strings (13) are then tensioned by means of their adjacent strings (16).



  Because the strings first passed the racket head and only then reached the trigger head, the friction of the string in the racket head was included in the tension achieved (58). This is achieved when the handle of the lever is pushed away from the strings. The central strings now have the tension indicated by the pin (58) on the trigger. This is the moment at which we will place the 1-string clamps as shown in Fig. 12.



  The clamps (60) are placed against the racket head for the first time.



  This allows us to place the round 2-string clamp (59). It is impossible now

  <Desc / Clms Page number 26>

 for the strings from the right-hand part of the racket (seen from the handle) to advance to the left-hand part. Once the round clamp has been placed and the racket has been properly clamped against the fixing blocks, we are ready to tighten each of these central strings again. We now draw each of them separately to the anticipated voltage. First one side, then the other side. And thus working, alternating a string on the left and a string on the right, we finish the entire plane. Those who wish can work analogously in the other direction. Sometimes, however, the shape of the racket or its manufacturer does not allow it to be used that way. Man is obliged to start at the top or bottom.

   In that case, and then only, one does not work alternately, but first finishes the side that the manufacturer believes must be done first: the top (If the manufacturer says to start at the top) or the bottom (If the manufacturer says to be at the bottom to start). In that case too, people work from the center. This gives the best spread of tension across the string bed.



   METHOD TO WHICH THE INVENTION IN THE INDUSTRY CAN BE APPLIED
The description of the invention gives clear instructions on how to make this machine and the accessories. Solidity of the materials is a basic condition. It should be clear that none of the materials may warp or deform unless this is the intention (such as with the anti-slip layer). The materials used and their intended purpose, however, provide a clear indication of these types of requirements.


    

Claims (8)

  CONCLUSION, 1. A racket machine and fixture machine for sports rackets, characterized by six externally placed and continuously adjustable support points with wing-nut shaped head and adjustable with nut on bolt against this support point, placed at positions 400 and 900 and 1400 and 2200 and 2700 and 320 with respect to the racket to be placed and where 00 determines the top of the racket, placed at a sufficient distance from the center of the device to allow all racket shapes, and whose wing-shaped and rack-sparing material covered head does not interfere with clamping or knots of strings with the wing nut facing the racket,  a connecting rod being provided between the support points at 90 and 270, the improvement being in the absence of the possibility of deformation of the racket in any direction other than the direction of the string bed, which is also the ideal direction with regard to distributing the tensioning force and having a corrective effect in the racket after leaving the clamping machine, the improvement also consisting of smaller supports than usual in the conventional machines, so that they do not necessarily have to be made entirely of metal, but possibly also of metal 20, for example, wood.  2. A clamping machine and clamping machine as characterized in claim 1 and provided with a trigger-lever mechanism for tensioning strings, consisting of a trigger and sufficiently long and possibly extendable lever arm to make work easy, wherein the trigger has an integrated force display. based on the clamping of a spring already brought to basic tension, this trigger being calibrated by measuring the tension force taking into account the friction of the wire in the racket head, the trigger rotating around a side arm of the lever arm, the same lever arm being rotatable 3600 and the tractor can move to and from the string bed at an ideal angle as further described in this claim,  wherein the improvement consists in the possibility of tensioning pre-woven rackets in view of the possibility of moving the trigger head towards the strings against the inside of the racket head if necessary and wherein the entire trigger forms the ideal angle, in the vertical and horizontal flat, with the string to be clamped out of the hole in the racket head where the string to be clamped ends so that there is minimal friction between the string and racket head and the measured tension is the angle that the string  <Desc / Clms Page number 28>  belt counts in the force that can be read on the tractor, which is applied when moving the handle of the lever away from the belt to be tensioned.  3. A chucking machine and chucking machine as in claim 2 characterized by a T-shaped trigger head to which the string is attached, wherein this trigger head is surrounded by a material with anti-slip properties, wherein this material is string-sparing, this material being somewhat uneven and possibly grooves where the improvement is that the string does not come into contact with metal parts when attaching to the chuck and the improvement consists in fastening the string in a manner where the string is first longitudinally and then perpendicular thereto around the trigger head is rotated to be fixed between string and trigger head and as a result, if the attachment is incorrect, no tension can be drawn on the string.  4. A clamping machine and clamping machine as in claim 3 characterized by 2 to 4 loose string clamps associated with the machine for clamping a string relative to the inside of the racket head, the dimensions of the string clamping plates relative to shape relative to thickness and width and length as 2 mm and 22 mm and 100 mm (but not limited to these dimensions), whereby the clamping plates on the non-clamping side are protected by another plate with racket-saving properties, whereby this protected plate enters the clamping plates circumference exceeds such that the tubings are not damaged by the metal parts during use, one side having a pointed end, the corners of the metal plates being rounded in order not to damage the string,  wherein there are 2 bolts and nuts for screwing these plates together at the corners, whereby these bolts do not interfere with clamping, with a 0.7 mm thick roundelette being placed over the bolts between the metal plates, whereby between the protective plate and nut the pointed or rounded side is successively a fan section and a roundel with a diameter of 4 cm, whereby the bolt with fan section also has a roundel with a diameter of 4 cm to protect the other protective plate, whereby the latter bolt can also be tightened around to clamp in proportion to the thickness of the string to be used, the improvement being that these clamps work relative to the inside of the racket head and that they do not prevent movement in the other direction,  where the improvement exists  <Desc / Clms Page number 29>  that a string cannot retract but can yield more than with conventional clamping mechanisms in the direction of tightening, whereby the improvement consists in the possible visual determination of the shift for control because one can see the clamp moving away from the racket head at higher than planned tension, where the improvement consists of the continuous and broad clamping surface of the clamps and their string-saving nature, where the improvement consists in the freedom of placement on any string of the string bed as long as the racket can be used as a support point, the improvement being the pointed clamp that allows a minimum of string and place to clamp where the round clamps can no longer be used,  wherein the improvement consists in the possibility to work with four clamps and also to keep clamping on the previous string so that when releasing a clamp, the entire surface does not have to be tensioned again.  5. A chucking machine and chucking machine as in claim 4 characterized by the presence or absence of a fixed machine base or chassis with the possibility of using this apparatus and the method at a table in which there is an improvement in that this machine is not covered by the racket must work what the existing models must do in view of the need for simultaneous weaving and tensioning of the strings.  6. A clamping machine and clamping machine as in claim 5 characterized by the use of a round 2-string clamp consisting of 2 wide washers, bolt with wing nut mounted on one side and matching wing nut for the other side, whereby it is possible to tighten it of the matching wing nut to clamp the 2 round pieces tightly together, whereby the improvement consists in the possibility of clamping two or more strings with a wide application surface and whereby the wing nuts come to lie below and above the string bed, whereby the improvement consists in avoiding of starting knots and easier starting of strings by means of starting loops in longitudinal and vertical direction,  wherein the improvement consists in clamping with this string clamp from the top of the starting loop against the inside of the racket head to prevent sliding of the string and allowing to avoid the conventional starting problems when clamping, the improvement consisting of being able to use these clamps for easier tie-off of string ends.  <Desc / Clms Page number 30>    7. A chucking machine and chucking machine as claimed in claim 6 characterized by a hand puller in which the leverage function is canceled, this trigger being used where the leverage function is superfluous, where the improvement consists in approximating the ideal angle as explained in claim 2 and increasing it of the machine's ease of use.  A clamping machine and clamping machine as in claim 6 characterized by a machine base with four legs and a base plate provided with a folding footboard and a bar connection between two legs to allow an even better anchoring of the device, the improvement consisting of an increased stability of the device without having to add additional weight to the base because the weight of the tensioner itself is used.  DESCRIPTION OF THE CHARACTERISTICS An apparatus for tensioning pre-woven, non-stretched strings in sports rackets contains six fixation blocks (2) that support the racket from the outside on the racket head. The racket rests in wing-nut-shaped, racket-protecting material surrounded and infinitely adjustable racket clamps that can be moved towards or away from the racket. Between the support points that support the width of the racket head at 90 and 2700 (with 00 as the top of the racket) a connection was made (53, 18) that excludes lateral movement of the supports. These racket clips are infinitely adjustable to fit perfectly with any racket shape. The fixing blocks are placed on a 3600 rotating turntable (5) which, via a rotating shaft (19), adheres to a base plate (20) with a lever-pull mechanism thereon. This consists of a lever arm (4) with a rotatable point mounted on the base plate with a rotatable trigger (3) with a built-in reading scale (23) to read the applied voltage. The lever arm consists of a handle (30) on the end, a trigger support rod (31), a side arm for mounting the rotary trigger (28) and a foot (29) rotatable in two directions.  The first direction around an axis perpendicular to the base plate through which the entire lever-trigger mechanism can rotate 3600, the second direction moves the lever arm in a plane that is always perpendicular to the base plate to cause the trigger to move away from and to the racket (21). The tractor itself consists of two telescopic sliding tubes (33, 34) with each  <Desc / Clms Page number 31>  a point of attachment on a spring (35) surrounded by the tubes and brought to basic tension. They attach via cylindrical elements (36, 37) that pierce the tubes. A T-piece is attached to the two ends of the tractor. The free end is surrounded by a belt-sparing, grooved, non-slip layer (39) for the temporary attachment of the belt loop (or belt end).  The other end is a T-piece that seamlessly connects to the side arm of the lever arm. Both T-pieces are fixed in a plane parallel to the base plate. To know the force used, a slit was made at the top of the outer tube (33), and a pin (38) was placed on the inner tube which can move along the slit. When tensioning the trigger, this pin moves in the slot in the direction of the lever arm. Grooved indications in the outer tube make it possible to use a scale, for example in the unit of measurement 'Kg'. Tensioning a string is done by bringing the free trigger end above the string bed and as close as possible to the inner edge of the racket, at the hole with the string to be clamped.  By turning the turntable and / or lever arm you can ensure that the trigger is just opposite the inside edge of the racket, just above the string bed. A pin (10) through turntable and base allows the turntable to be locked in this or any other desired position. This is made possible through coordinated openings (1, 17) in both parts, which closely enclose the pin. By removing the lever handle now away from the racket, the string stretches itself in a plane that approaches the extension of the string bed, so that the developed force loads the racket in a direction for which it was developed. And the free string loop (or the string end) does not have to be large, since it is possible to move the trigger towards the racket head before attaching the string. The racket becomes light, about 1 mm inwards, deformed and the muscle strength to use is minimal, also because the basic tension of the spring means that the lever does not have to be moved far. For badminton rackets and squash rackets it is even possible (and more convenient) to work with a hand puller.  One then disengages trigger from lever and uses this released tee as a handle. The aforementioned restrictions on movement of the tractor then expire insofar as they relate to the lever arm. The tensioned string is clamped against the racket with wide, self-positioning 1-string clamps (8) (round or pointed depending on the openings in the string bed). The metal core surfaces become  <Desc / Clms Page number 32>    eg, kept from the racket by plates made of non-damaging material which slightly surpass the metal plates in circumference. As a result, neither tubings nor racket are damaged and the clamping is nevertheless the most ideal point, namely when the string returns to the inside of the racket head. The wide, interchangeable, adjustable tils are not provided with diamond powder. The voltage read on the tension meter also counts the friction caused by the passing of the string in the passed holes of the racket head. At no time is it necessary to work under the racket as with current, typical clamping machines. You can work while sitting or standing. The latter uses a machine base (6) consisting of 4 sturdy legs, a foot plate 54 and a foldable footboard (14) that is attached to the foot plate with hinges (22).  Between 2 of the 4 legs, in accordance with the reinforcement between the fixing blocks at 90 and 2700 (with 0 as the top of the racket), a reinforcement (24) was provided in the direction with the greatest load (longitudinal direction) of the device. . The folding foot allows you to stand on the device and anchor it firmly with your body weight. The round 2-string clamp (9), which clamps 2 adjacent strings without diamond powder, also has a wide clamping surface and is used like the other clamps against the racket head. You will use this when starting the clamping to prevent slipping if you first want to tension the left / right or top / bottom segments of the strings separately. One then starts to clamp and clamp together with the most centrally located two strings of the working direction. Here too the tractor will be above the string bed. After placing the l-string clamps, the round 2-string clamp can then be used to fix it relative to each other at the height of the racket head and close to the top of the starting loop.  Working with two strings and starting from the middle of the strings and thus outwards, both longitudinally and transversally, gives the best results. Because the racket is somewhat distorted inwards (approximately 1 mm), it will wish to resume its normal shape when removed from the device. In doing so, it once again tightens the strings that thereby retain their required tension for longer.