US20160136486A1

US20160136486A1 - Method and Apparatus for Real-Time Racket String Tension Measurement

Info

Publication number: US20160136486A1
Application number: US14/943,883
Authority: US
Inventors: Dusan Pittner
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-11-17
Filing date: 2015-11-17
Publication date: 2016-05-19

Abstract

A sports racket with racket string tension measurement has a racket frame with a throat that connects a racket head and a racket grip. One or more strings is strung in a stringing pattern, and one or more string anchors retains an end of the string or strings. A tension measurement gauge, such as a strain gauge, is operably associated with the string to sense a tension therein. At least a portion of the tension measurement gauge can be retained by the at least one string anchor, and measured tension can be output to a display. There can be first and second strings strung in a pattern to establish distinct striking zones within the racket head, and tension measurement gauges can be associated with each string. A third string could be strung to establish a peripheral pattern in the racket head.

Description

FIELD OF THE INVENTION

The present invention relates generally to striking implements. More particularly, disclosed and protected herein are a method and apparatus for providing real-time measurements of racket string tensions, for providing contoured string tension patterns, and for anchoring strings to permit increased string tension and increased string tension control.

BACKGROUND OF THE INVENTION

In a typical stringed sports racket, such as a tennis racket, a head has a central opening with string holes spaced around the circumference thereof. A handle or grip is connected to a proximal end of head by a throat. Stringing, typically in the form of a single string, is strung through the string holes and across the opening during a stringing process. Portions of the stringing extend in a first, cross-string direction, and other portions of the stringing extend in a second, main string direction. The main stringing and the cross stringing are typically disposed in a single plane. The cross strings are generally perpendicular to the handle of the racket, and the main strings are generally parallel with the handle of the racket such that the main strings are substantially perpendicular to the cross strings. When applied, the stringing permits a controlled striking of objects, such as tennis balls. Weaving patterns and the number of main strings and cross strings vary based on, for example, the size of the racket, the object to be struck, and the goals of the manufacturer and player.
In a typical stringing method, a racket string is pulled in tension through the string holes in the racket head thereby generating a taut hitting surface. The spacing between the strings allows air to pass through the racket head during a player's swing so that substantial racket speed can be developed with a resultant striking capability and an ability to impart speed to the game projectile. The string can be of natural or synthetic material. Strings typically have a cross -sectional diameter from about 14 to 20 gauge or about 0.8 to 1.7 mm.
Stringing is generally performed manually by first providing a string set, which can comprise one or two coils of string with about ten meters in total length. The racket frame is mounted to a stringing machine, and the main strings are threaded into the racket through the corresponding string holes. The string is then normally clamped and pulled to a predetermined tension. Once pulled, the string can be clamped, and the subsequent strings are threaded and pulled until all main strings are in place. Then, the end of the string set is tied off with the goal of preserving the pulled tension. The tie-off typically involves inserting the string through a hole and knotting it around and in direct contact with an already pulled string. A weave process is then performed to string the cross strings, with tensioning and clamping similarly performed. Upon stringing the final cross string, another tie-off occurs. Classic single-stringing techniques will typically result in two knots, namely a starting knot and an ending knot, while dual-stringing techniques will require four knots.
Unfortunately, the string knots introduce vulnerability and tension loss into the stringing.
Over time, for instance, string knots can slide and give thereby producing an unintentionally and unpredictably lowered string tension. Moreover, knots present a location that results in a high frequency of breakage, such as from a localized thinning of the tie-off string about which the knot is made, often referred to as choking. Breakage deriving from the string knot can also derive from abrasion due to shearing of the knot string about the tie-off string, shear forces from the knot, or some combination thereof. Further, knots themselves can sometimes tolerate only so much tension before unwinding. With that, the possible tension in a string may be limited more by the ability of the knot to withstand a given level of tension immediately and over time than the strength of the string or frame itself.
One experienced in the art will further appreciate that numerous systems and devices have been disclosed for providing a measurement of string tension in a completed racket. However, such systems and methods have invariably been separate from the racket. As such, they obtain measurements of string tension only in isolated instances of time, such as in the workshop or factory immediately after stringing.
However, string tension changes over time and based on current conditions. For example, the string itself can relax over time, commonly referred to as creep, and knots can compress and slide. Furthermore, changes in temperature can, for instance, cause a racket that measured at one tension in the workshop to exhibit a different tension during live play on a hot court. With that, a person believing his or her racket to be at a certain tension may be unpleasantly surprised to find the racket in actuality be at a much less preferred and unknown tension.
Those knowledgeable in the art will also be aware that a basic goal of many inventors has been to provide a racket stringing system and method with greater control over string pattern characteristics and resultant ball striking performance. In many instances, inventors have sought to develop stringing and resultant rackets that produce a larger sweet spot so that balls can be struck with greater velocity. Others have sought to provide rackets with different striking surfaces providing different striking characteristics. One such method, for example, is to provide a double-strung racket head with first and second string sets in spaced, parallel planes. With that, different striking characteristics can be achieved in a single racket. However, such stringing methods have been of limited effectiveness and have proven overly complex and expensive in construction thereby preventing widespread adoption.
With a knowledge of the foregoing, the present inventor has appreciated that there is a need in the art for a method and apparatus for sports rackets that provides real-time tension measurement. There is also a need in the art for a system and method for racket stringing that reduces the required string knots thereby reducing tension loss, permitting higher string tensions, and limiting vulnerability to breakage. Still further, there is a need in the art for a racket stringing method and system that permits enhanced control over striking surface characteristics, including by providing varied performance characteristics and, potentially, larger and perhaps multiple areas of preferred performance.

SUMMARY OF THE INVENTION

In view of the state of the art as summarized hereinabove, the present inventor set forth with a basic object of providing an apparatus and method for providing real-time measurement of string tension in a sporting racket.
An underlying object of embodiments of the invention is to enable athletes to determine, on demand or automatically, string tension in a sporting racket to confirm desired tension parameters and to be apprised of undesired changes in string tension.
A related object of embodiments of the invention is to enable a determination of string tension in a sports racket without specialized tools and in any environment.
In certain embodiments, an object of the invention is to minimize the number of required string knots in a racket stringing process thereby to minimize the deleterious effects thereof, including tension limitations, losses in tension, and breakage.
Another object of the invention, in particular embodiments, is to enable greater control over string pattern characteristics and resultant ball striking performance.
A more particular object of manifestations of the invention is to provide a stringing system and method that yields a larger sweet spot.
A further object of embodiments of the invention is to enable the creation of different ball striking performance characteristics over given portions of a racket face.
These and further objects, advantages, and details of the present invention will become obvious not only to one who reviews the present specification and drawings but also to those who have an opportunity to make use a sports racket incorporating an embodiment of the racket string methods and apparatuses disclosed herein. However, it will be appreciated that, although the accomplishment of each of the foregoing objects in a single embodiment of the invention may be possible and indeed preferred, not all embodiments will seek or need to accomplish each and every potential advantage and function. Nonetheless, all such embodiments should be considered within the scope of the present invention.
In carrying forth one or more objects of the invention, an embodiment of the sports racket with racket string tension measurement is founded on a racket frame with a racket head, a racket grip, and a throat that connects the racket head and the racket grip. The racket head defines a central opening, and a plurality of string holes are disposed through the racket head of the racket frame in spaced relation around a periphery of the racket head. At least one string with a first end and a second end is provided for being strung through the string holes in the racket frame to establish a stringing pattern, and at least one string anchor is provided for retaining one of the first and second ends of the at least one string.
In practice, the at least one string is strung through the string holes in the racket frame with main string portions that communicate longitudinally generally parallel to the racket grip and cross string portions that communicate generally perpendicularly to the main string portions. The at least one string anchor can retain the first end of the at least one string, and the at least one string anchor can be disposed at least partially distal to the periphery of the racket head. In certain embodiments, the first end of the at least one string can be unitarily formed with at least a portion of the at least one string anchor.
Moreover, a tension measurement gauge can be coupled to the at least one string. For instance, at least a portion of the tension measurement gauge can be retained by the at least one string anchor, either by being coupled to the string and derivatively retained by the anchor, by being coupled to the string anchor directly, or both.
A tension measurement output can be electrically coupled to the tension measurement gauge. For example, the output could be an electrical lead for being coupled to an electronic display, or it could include a display itself.
The tension measurement gauge can be a strain gauge in certain practices of the invention. By way of example, a block of material can be fixed over a length thereof to the at least one string, and a pattern of conductive material can be disposed to communicate along the block. Through a bridge circuit, for example, and associated logic, a resistance of the conductive material can be converted to a real-time tension in the string.
It is contemplated that at least first and second strings and can be employed. In such embodiments, at least one string anchor can be provided for each of the first and second strings. Moreover, a first tension measurement gauge can be coupled to the first string, and a second tension measurement gauge can be coupled to the second string. In certain embodiments, the first ends of the first and second strings can be received through string holes immediately outboard of a longitudinal centerline of the racket thereby to sense tension in central main string portions of the racket head.
Where first and second strings are employed, the strings can, for example, be strung through the string holes in the racket frame with the first string strung to form main strings to a first side of the racket head and cross strings to a proximal portion of the racket head and with the second string strung to form main strings to a second side of the racket head and cross strings to a distal portion of the racket head. With this, a stringing pattern with four quadrants is formed with a first quadrant formed in the distal, first side portion of the racket head with main string portions of the first string and cross string portions of the second string, a second quadrant in the distal, second side portion of the racket head composed entirely of main string portions and cross string portions of the second string, a third quadrant in the proximal, first side portion of the racket head composed entirely of main string portions and cross string portions of the first string, and a fourth quadrant in the proximal, second side portion of the racket head with main string portions formed by the second string and cross string portions formed by the first string.
In other embodiments, a third string can be strung through the string holes in the racket head. The third string could, for example, form a peripheral pattern in the racket head, and the first and second strings can form a pattern interior of the peripheral pattern formed by the third string.
It is further within the scope of the invention for the string anchor to comprise a base portion and a plurality of string guide sleeves that project from the base portion for being received into string holes in the racket head. In such embodiments, one or more tension measurement gauges can be coupled to the at least one string, and the tension measurement gauge or gauges could be retained by the string anchor.
One will appreciate that the foregoing discussion broadly outlines the more important goals and features of the invention to enable a better understanding of the detailed description that follows and to instill a better appreciation of the inventor's contribution to the art. Before any particular embodiment or aspect thereof is explained in detail, it must be made clear that the following details of construction and illustrations of inventive concepts are mere examples of the many possible manifestations of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawing figures:

FIG. 1 is a view in front elevation of a racket with real-time string tension measurement devices as taught herein;

FIG. 2 is a schematic view of string tension zones established pursuant to the devices and methods of the present invention;

FIG. 3 is a schematic view of first and second strings strung on a racket head according to the invention disclosed herein;

FIG. 4 is a sectioned view of first and second real-time tension measurement devices retaining first and second string ends;

FIG. 5 is an electrical schematic for a Wheatstone bridge operative according to the invention;

FIG. 6 is a view in front elevation of an alternative embodiment of a racket with real-time string tension measurement devices;

FIG. 7 is a view in front elevation of another embodiment of a racket with a real-time string tension measurement device as disclosed herein;

FIG. 8 is an amplified sectioned view of the tension measurement device of FIG. 7;

FIG. 9 is a view in front elevation of a racket segment with an alternatively positioned tension measurement device;

FIG. 10 is a view in front elevation of the tension measurement device of FIG. 9;

FIG. 11 is a view in front elevation of an alternative tension measurement device; and

FIG. 12 is a schematic view of first, second, and third strings strung on a racket head according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The methods and apparatuses for real-time racket string tension measurement disclosed herein are subject to a wide variety of embodiments. However, to ensure that one skilled in the art will be able to understand and, in appropriate cases, practice the present invention, certain preferred embodiments of the broader invention revealed herein are described below and shown in the accompanying drawing figures.
Looking more particularly to the drawings, a sports racket, such as a tennis racket, is indicated generally at 10 in FIG. 1. The racket 10 is founded on a frame 15 that has a first or distal end that comprises a head 12 and a second or proximal end that comprises a grip 18 that is grasped for play. The head 12 and the grip 18 are connected by a throat 16. The head 12 defines a central opening. Stringing, generally designated at 14 in FIG. 1, is strung across the opening for the purpose of striking objects. Portions of the stringing 14 extend in a first, cross-string direction, and other portions of the stringing 14 extend in a second, main string direction. The head 12 of the racket 10 has string holes spaced around the circumference of the racket head 12. The stringing 14 is inserted through the holes during the stringing process. The cross strings are generally perpendicular to the handle grip 18 of the racket 10, and the main strings are generally parallel with the grip 18 of the racket 10. Thus, the main strings are substantially perpendicular to the cross strings. The weaving pattern and the number of main strings and cross strings can vary depending on several factors, including the size of the racket 10, the object to be struck, and the goals of the manufacturer.
In the depicted embodiment of FIG. 1, the stringing 14 of the racket head 12 is carried out with a first string 14A strung to form a plurality of main strings and cross strings and a second string 14B strung to form a different plurality of main strings and cross strings. The first string 14A has a first end or start S1, a body portion strung under tension to form the several main strings and cross strings, and a second end E1. The second string 14B has a first end or start S2, a body portion strung under tension to form the several main strings and cross strings, and a second end E2.
Here, the starts S1 and S2 of the first and second strings 14A and 14B form the proximal ends of the main strings immediately outboard of the longitudinal centerline of the racket 10. The end E1 of the first string 14A forms the proximal end of the third main string from a first side of the racket 10, and the end E2 of the second string 14B forms the distal end of the fourth main string from that first side of the racket 10.
The first and second strings 14A and 14B can differ in one or more string characteristics. By way of example and not limitation, the strings 14A and 14B could differ in gauge, elasticity, or, additionally or alternatively, resilience. The difference in string characteristics is illustrated schematically in FIG. 3. There, the first string 14A is depicted as being a certain gauge with the second string 14B being of a heavier gauge. The racket head 12 is strung with the first string 14A forming the main strings to the left of the head 12 and the cross strings to the proximal portion of the head 12. The second string 14B is strung to form the main strings to the right of the head 12 and the cross strings to the distal portion of the head 12.
With that, four quadrants, each having a different string composition, are formed. What can be referred to as a first quadrant is formed in the distal left portion of the racket head 12 with main string portions of the first string 14A and cross string portions of the second string 14B. The first quadrant encompasses a first zone Z1. A second quadrant is formed in the distal right portion of the racket head 12 composed entirely of main string portions and cross string portions of the second string 14B. A third quadrant is formed in the proximal left portion of the head 12 composed entirely of main string portions and cross string portions of the first string 14A, and a fourth quadrant is formed in the proximal right portion of the head 12 with main string portions formed by the second string 14B and cross string portions formed by the first string 14A.
Consequently and as is further illustrated in the schematic view of FIG. 2, the first quadrant encompasses a first zone Z1, the second quadrant encompasses a second zone Z2, the third quadrant encompasses a third zone Z3, and the fourth quadrant encompasses a fourth zone Z4. Being formed with string compositions entirely of the first string 14A, entirely of the second string 14B, and combinations of the first and second strings 14A and 14B in different dispositions, each of the zones Z1, Z2, Z3, and Z4 has different performance characteristics compared to the others. The illustrated sizes of the zones Z1, Z2, Z3, and Z4 are not necessarily proportionately representative of the spring force of the respective zone, only that at least some of the zones Z1, Z2, Z3, and Z4 differ in performance characteristics based on the string 14A or 14B or strings 14A and 14B forming the same. With this, the racket head 12 will tend to exhibit different ball striking characteristics depending on which zone Z1, Z2, Z3, or Z4 is used to strike the ball. The player with the racket 10 so strung can employ the different zone characteristics to accomplish different striking goals, to confuse opponents, and otherwise. Larger and even plural sweet spots can be created.
Other stringing patterns are contemplated within the scope of the invention. For example, as FIG. 12 illustrates, further strings could be employed to create a multi-zone stringing pattern in the racket head 12. There, the racket head 12 is strung with first, second, and third strings 14A, 14B, and 14C. The stringing pattern can be established by first threading the third string 14C in the rectangular, peripheral pattern illustrated, which in this manifestation has three main strings to each side of the racket head 12 and three cross strings to each of the proximal and distal portions of the racket head 12 with it being understood that fewer or more main or cross strings are possible. So disposed, the third string 14C acts as a booster string for putting preliminary tension on the racket head 12. Then, the first and second strings 14A and 14B can be strung on the racket head 12 to equalize the stresses on the head 12 and to establish a desired racquet frame stress pattern and shape. The first and second strings 14A and 14B could again be strung to establish a four quadrant pattern as previously shown and described. Large, sensitive playing areas can be established with individual zones exhibiting desired performance characteristics.
With further reference to the embodiment of FIG. 1 in combination with the cross-sectional views of FIGS. 4 and 5, it can be seen that one or both ends, in this case the first ends S1 and S2 of the first and second strings 14A and 14B, are secured by respective string anchors 22 and 24 rather than solely by string knots as is common in the prior art. With this, the number of string knots required to retain the strings 14A and 14B in position is diminished. If string anchors 22 and 24 were employed at both ends S1, S2, E1, and E2 of both strings 14A and 14B, the need for string knots would be eliminated. Alternatively, as illustrated, the number of string knots is halved where one end S1 and S2 is retained by a string anchor 22 or 24 rather than a string knot. Where one string 14A would normally require two knots, it would require just one. Where two strings 14A and 14B would require four total knots, they would require just two. With this, the disadvantageous effects of string knots are minimized or eliminated. The risks and effects of a string knot untying, sliding, or weakening the string 14A or 14B are diminished.
The anchoring members 22 and 24 can vary within the scope of the invention. The anchoring members 22 and 24 here are disposed external to the frame defining the head 12. The depicted anchoring members 22 and 24 comprise blocks with the end of the respective string 14A or 14B retained thereby. As is illustrated, for example, in FIG. 4, each anchoring member 22 and 24 can be aligned with a string hole in the racket head 12 and can have the end portion of the respective string 14A and 14B fixedly retained thereby. This could be carried out by integral formation of the string end with the anchoring member 22 or 24 to form a cap 30A and 30B as illustrated in FIG. 4. It could also be carried out by passing the string 14A or 14B through a central aperture of the anchoring member 24 and fixing it in place as in FIG. 8 or in some other manner. The fixation of the string end 40 could in theory be formed by a knot. However, to eliminate such a string knot, the string end 40 could be formed during manufacture as a fixed block, bulbous, or enlarged portion integrally and unitarily with the body of the string 14A or 14B, or the end of the string 14A or 14B can be fixed to a bulbous or enlarged portion thereby preventing the string end 40 from being pulled through the anchoring member 24 or through the string hole in the racket head 12. With this, the effects of string knots can be minimized, and potentially greater tensions can be applied to the racket stringing 14 than is possible with the string knotted ends of the prior art.
The anchoring member or members 22 and 24 can incorporate real-time string tension measurement devices. With this, the actual string tension can be determined in an on-demand or automatic basis outside of the factory and workshop and, potentially, without a need for separate equipment. The anchoring members 22 and 24, which individually or in combination act as a string tension measurement system, include at least one tension gauge, which could be of any effective type, and the anchoring member or members 22 and 24 are or can be coupled to a tension measurement output, such as a display, and electronic logic circuitry for permitting determination, display, and reading of the actual tension in the string or strings 14A and 14B.
In the embodiment of FIGS. 1 and 4, each anchoring member 22 and 24 is operative to measure and output tension in the respective string 14A and 14B by the incorporation of a strain gauge that outputs measured strain for conversion to real-time string tension, but it will again be appreciated that other electronic or non-electronic tension measurement devices are possible and within the scope of the invention. Blocks 28A and 28B of resilient material are fixed over their respective lengths to the strings 14A and 14B to stretch and contract therewith. The blocks 28A and 28B can envelop the respective lengths of the strings 14A and 14B. Zig-zag patterns of conductive material 36A and 36B are disposed to communicate along the blocks 28A and 28B. The blocks 28A and 28B can be rectangular in cross section and can have zig-zag strain gauge conductive material 36A and 36B disposed along each of four longitudinal faces thereof. Accordingly, as the strings 14A and 14B are stretched or contracted by a change in string tension, the blocks 28A and 28B will similarly deform thereby causing a change in electrical resistance in the conductive material 36A and 36B. The string tension can thus be constantly monitored by the tension measurement devices even after the main strings and the cross strings are strung.
The change in resistance can be measured, such as by a Wheatstone bridge 66 as depicted in FIG. 5, and converted to real-time string tension electronically by use of the gauge factor of the strain gauges. More particularly, the four lengths of strain gauge material 36A and 36B of each anchoring member 22 and 24 are connected in a Wheatstone bridge circuit 66. Power sources 34A and 34B can be electrically coupled to the strain gauges 36A and 36B to provide a source of voltage to supply power across one arm of the bridge 66. Here, the ends of the strings 14A and 14B are integrally formed to establish caps 30A and 30B, and the power sources 34A and 34B, such as batteries, are retained by the caps 30A and 30B. An output reading can be taken across a second arm of the bridge 66 and electronically output, such as to a display, which is indicated at 78 in FIG. 5 through electronic logic circuitry as shown, for instance, in FIG. 8.
In the embodiment of FIG. 4, an output cable 26 is provided for being selectively coupled to the display 78, which can incorporate all or some of the remaining circuitry and logic of the system. The display 78 can provide digital output readout of the tension in the respective string 14A or 14B. It will be appreciated that various auxiliary calibration resistors, zeroing resistors, and other electronic components may be used to provide for the proper operation of the bridge circuit 66 and the tension measurement devices in general with such components being obvious to a person skilled in the art after reading the present disclosure. It will further be appreciated that other types of tension measurement gauges are possible and within the scope of the invention except as it may be expressly limited by the claims.
An alternative embodiment of the racket 10 is illustrated in FIG. 6. There, the racket 10 again has a head 12 and a grip 18 connected by a throat 16. The head 12 defines a central opening. A stringing pattern 14 of the racket head 12 is established by first and second strings 14A and 14B.
The first ends of the first and second strings 14A and 14B pass through string holes in the racket head 12 to be retained by first and second anchoring members 22 and 24. Each anchoring member 22 and 24 again incorporates a tension gauge. In this embodiment, however, the first anchoring member 22 is electrically connected to output measured tension in the first string 14A to a first individual display 44, and the second anchoring member 24 is electrically connected to output measured tension in the second string 14B to a second individual display 46. The displays 44 and 46 can be fixed in place, or they could be removable and replaceable. Tension measurement and, additionally or alternatively, tension display can be performed automatically, continuously, or selectively, such as by actuation of an actuation mechanism, potentially a switch or a button, by a user.
Under the teachings of the present invention, therefore, a user can be provided with real-time information regarding the tension in the first and second strings 14A and 14B. This can permit, among other things, monitoring and collecting of racket stringing parameters and variations in parameters over time and under known conditions with the elimination of undesirable guesswork. The monitored and collected data can enable selective adjustments or other actions and can facilitate, among other things, the development of new string and racket materials and improved racket designs. Accumulated data can enable customization, immediate and knowledgeable understanding of and reaction to changing ambient conditions, and adjustments to particular opponents and playing conditions. Variations in string tension over the length of a match or over the life of the racket 10 can be immediately recognized, understood, and accommodated thereby avoiding unanticipated changes in performance and other undesirable results. With fewer vulnerabilities in the stringing 14 and greater knowledge about live tension values, tension characteristics can be varied and, potentially, increased to levels beyond those generally permitted under the prior art thereby permitting, among other things, ball striking producing speeds previously deemed impossible. Still further, by use of the real-time sensing disclosed herein, injuries can be prevented and minimized, including by an immediate discovery of failing strings and other anomalous string tension characteristics that could otherwise lead to injury. By enabling accurate, known stringing, rackets 10 possessed of the real-time sensing technology disclosed herein are rendered more useful and more valuable. Indeed, with optimal tension adjustment and known variations in string tension, a relatively low cost racket 10 can be caused to perform at a higher level than would otherwise be expected.
Another embodiment of the racket 10 is shown in FIG. 7. A head 12 is coupled to a grip 18 by a throat 16. A stringing pattern 14 is again established by first and second strings 14A and 14B as shown in the partial view of FIG. 8. In the present embodiment, however, tension in the first and second strings 14A and 14B is measured by a unitary anchoring member 48. The anchoring member 48 has an arcuate base portion 56 for being disposed against a proximal portion of the racket head 12, and a plurality of string guide sleeves 58 project from the base portion 56 for being received by aligned string holes in the racket head 12. The base portion 56 has arcuate ridges 60 between the guide sleeves 58 for guiding the strings 14A and 14B in an smooth path as they pass between string holes.
The ends of the first and second strings 14A and 14B are received into a rigid casing 55 of the anchoring member 48 that is fixed to a central portion of the base portion 56 and are retained by the casing 55. More particularly, each string 14A and 14B has a bulbous or broadened end portion 40 retained by the rigid casing 55 of the anchoring member 48. The anchoring member 48 is operative to measure and output tension in each string 14A and 14B by the incorporation of tension gauges. Again in the present embodiment, tension is measured by use of strain gauges that output measured strain for conversion to real-time string tension. Blocks 50A and 50B of resilient material are secured to the strings 14A and 14B to stretch and contract therewith, and zig-zag patterns of conductive material 53A and 53B are disposed to communicate along the blocks 50A and 50B. The blocks 50A and 50B are rectangular in cross section and can have zig-zag strain gauge conductive material 53A and 53B disposed along each of the four longitudinal faces thereof. Accordingly, as the strings 14A and 14B are stretched or contracted by a change in string tension, the blocks 50A and 50B will similarly deform thereby causing a change in electrical resistance in the conductive material 53A and 53B.
Power can be provided by one or more power sources 54 electrically connected to the conductive material 53A and 53B and to a circuit board 52 with integrated logic for converting output resistance to a string tension to be displayed on the display of the anchoring member 48. As is illustrated in FIG. 7, it would be possible to have a single display that could automatically or selectively be caused to measure and output the measured tension in either the first string 14A or 14B such that a user can be provided with real-time information regarding the tension in the first and second strings 14A and 14B.
It will be understood that anchoring members as taught herein could be differently located and differently configured. By way of example and not limitation, an anchoring member could additionally or alternatively be disposed to receive and retain the second end of a string of the stringing 14 as is shown, for instance, in FIG. 9 where the anchoring member is indicated at 62. Such anchoring members 62 will thus tend to be disclosed laterally further away from the centerline of the racket head 12. Moreover, the shape of the anchoring member 62 could vary widely. In FIG.
10, for example, an anchoring member 62 is shown with an annular cross section and a central aperture 64 for receiving and retaining the second end of a string (not shown). A plate-shaped anchoring member 62 is shown in FIG. 11, again with a central aperture 64 for receiving and retaining the second end of a string (not shown).
It would be possible for the systems and devices disclosed herein to be provided in a racket stringing kit. The stringing kit could, for example, include one or more racket strings 14A, 14B, and 14C and one or more anchoring members 22, 24, 48, or 62. The strings 14A, 14B, and 14C and the anchoring member or members 22, 24, 48, or 62 could include tension gauges, and an integrated or separate display or displays 44, 46, or 78 can be provided as shown and described herein.
With certain details and embodiments of the present invention for racket string tension devices and methods disclosed, it will be appreciated by one skilled in the art that numerous changes and additions could be made thereto without deviating from the spirit or scope of the invention. This is particularly true when one bears in mind that the presently preferred embodiments merely exemplify the broader invention revealed herein. Accordingly, it will be clear that those with major features of the invention in mind could craft embodiments that incorporate those major features while not incorporating all of the features included in the preferred embodiments.
Therefore, the following claims shall define the scope of protection to be afforded to the inventor. Those claims shall be deemed to include equivalent constructions insofar as they do not depart from the spirit and scope of the invention. It must be further noted that a plurality of the following claims may express certain elements as means for performing a specific function, at times without the recital of structure or material. As the law demands, any such claims shall be construed to cover not only the corresponding structure and material expressly described in this specification but also all equivalents thereof.

Claims

I claim as deserving the protection of Letters Patent:

1. A sports racket with racket string tension measurement, the sports racket comprising:

a racket frame with a racket head, a racket grip, and a throat that connects the racket head and the racket grip wherein the racket head defines a central opening and wherein a plurality of string holes are disposed through the racket head of the racket frame in spaced relation around a periphery of the racket head;

at least one string with a first end and a second end for being strung through the string holes in the racket head to establish a stringing pattern;

at least one string anchor for retaining one of the first and second ends of the at least one string.

2. The sports racket of claim 1 wherein the at least one string is strung through the string holes in the racket frame with main string portions that communicate longitudinally generally parallel to the racket grip and cross string portions that communicate generally perpendicularly to the main string portions and wherein the at least one string anchor retains the first end of the at least one string and wherein the at least one string anchor is disposed at least partially distal to the periphery of the racket head.

3. The sports racket of claim 2 wherein the first end of the at least one string is unitarily formed with at least a portion of the at least one string anchor.

4. The sports racket of claim 2 further comprising a tension measurement gauge operably associated with the at least one string to sense a tension in the at least one string.

5. The sports racket of claim 4 wherein at least a portion of the tension measurement gauge is retained within the at least one string anchor.

6. The sports racket of claim 4 further comprising a tension measurement output electrically coupled to the tension measurement gauge.

7. The sports racket of claim 5 wherein the tension measurement gauge comprises a strain gauge.

8. The sports racket of claim 7 wherein a block of material is fixed over a length thereof to the at least one string and wherein a pattern of conductive material is disposed to communicate along the block.

9. The sports racket of claim 6 wherein the tension measurement output comprises a display.

10. The sports racket of claim 9 wherein the display is retained by the at least one string anchor.

11. The sports racket of claim 1 wherein there are at least first and second strings and at least one string anchor for each of the first and second strings.

12. The sports racket of claim 11 wherein a first tension measurement gauge is operably associated with the first string to sense a tension in the first string and a second tension measurement gauge is operably associated with the second string to sense a tension in the second string.

13. The sports racket of claim 11 wherein the first ends of the first and second strings are received through string holes immediately outboard of a longitudinal centerline of the racket.

14. The sports racket of claim 11 wherein the first and second strings are strung through the string holes in the racket frame with the first string strung to form main strings to a first side of the racket head and cross strings to a proximal portion of the racket head and with the second string strung to form main strings to a second side of the racket head and cross strings to a distal portion of the racket head whereby a stringing pattern with four quadrants is formed with a first quadrant formed in the distal, first side portion of the racket head with main string portions of the first string and cross string portions of the second string, a second quadrant in the distal, second side portion of the racket head composed entirely of main string portions and cross string portions of the second string, a third quadrant in the proximal, first side portion of the racket head composed entirely of main string portions and cross string portions of the first string, and a fourth quadrant in the proximal, second side portion of the racket head with main string portions formed by the second string and cross string portions formed by the first string.

15. The sports racket of claim 11 further comprising a third string strung through the string holes in the racket head wherein the third string forms a peripheral pattern in the racket head and the first and second strings form a pattern interior of the peripheral pattern formed by the third string.

16. The sports racket of claim 2 wherein the string anchor comprises a base portion and a plurality of string guide sleeves that project from the base portion for being received into string holes in the racket head.

17. The sports racket of claim 16 further comprising a tension measurement gauge operably associated with the at least one string.

18. The sports racket of claim 17 wherein at least a portion of the tension measurement gauge is retained by the string anchor.

19. A sports racket with racket string tension measurement, the sports racket comprising:

a first string with a first end and a second end wherein the first string is strung through string holes in the racket head;

a second string with a first end and a second end wherein the second string is strung through string holes in the racket head;

at least one string anchor that fixedly retains the first ends of the first and second strings.

20. The sports racket of claim 19 wherein there are first and second string anchors wherein the first string anchor retains the first end of the first string and the second string anchor retains the first end of the second string.

21. The sports racket of claim 19 further comprising a tension measurement gauge operably associated with the first string to sense a tension in the first string and a tension measurement gauge operably associated with the second string to sense a tension in the second string.

22. The sports racket of claim 21 wherein at least a portion of each tension measurement gauge is retained within the at least one string anchor.

23. The sports racket of claim 22 wherein a block of material is fixed over a length thereof to the first string and wherein a pattern of conductive material is disposed to communicate along the block and wherein a block of material is fixed over a length thereof to the second string and wherein a pattern of conductive material is disposed to communicate along the block.

24. The sports racket of claim 19 wherein the first ends of the first and second strings are received through string holes immediately outboard of a longitudinal centerline of the racket.

25. The sports racket of claim 19 wherein the first and second strings are strung through the string holes in the racket frame with the first string strung to form main strings to a first side of the racket head and cross strings to a proximal portion of the racket head and with the second string strung to form main strings to a second side of the racket head and cross strings to a distal portion of the racket head whereby a stringing pattern with four quadrants is formed with a first quadrant formed in the distal, first side portion of the racket head with main string portions of the first string and cross string portions of the second string, a second quadrant in the distal, second side portion of the racket head composed entirely of main string portions and cross string portions of the second string, a third quadrant in the proximal, first side portion of the racket head composed entirely of main string portions and cross string portions of the first string, and a fourth quadrant in the proximal, second side portion of the racket head with main string portions formed by the second string and cross string portions formed by the first string.

26. The sports racket of claim 25 further comprising a third string strung through the string holes in the racket head wherein the third string forms a peripheral pattern in the racket head and the first and second strings form a pattern interior of the peripheral pattern formed by the third string.