WO2009043558A1

WO2009043558A1 - Force sensor for racquet handle

Info

Publication number: WO2009043558A1
Application number: PCT/EP2008/008231
Authority: WO
Inventors: Frank Exner; Ralf Schwenger
Original assignee: Head Technology Gmbh
Priority date: 2007-09-28
Filing date: 2008-09-26
Publication date: 2009-04-09
Also published as: EP2195100B1; ES2790592T3; DE202007013632U1; EP2195100A1

Abstract

The present invention relates to a handle (4) for a piece of sport equipment, particularly for a tennis, squash, racquetball, table tennis, or badminton racquet, or golf club. The handle has a force measurement device (11) attached thereto, which is suitable for measuring a force acting on the handle applied by the hand of a player surrounding said handle. The handle further comprises an electronic analysis unit (16) that is electrically connected to the force measurement device. The force measurement device comprises at least one force sensor (12) with a flat design that is attached to the handle such that the force transferred from the player's hand can be measured by the force sensor.

Description

Force sensor for club grip

The invention relates to a handle for a sports device, in particular for a tennis, squash, racquet, Paddletennis-, badminton or golf clubs, with an attached force measuring device.

In tennis, as well as in similar ball sports, such as golf, badminton or squash, the task of a player is to include with the hand of his punch arm a bat and to beat this with the club face against an approaching or dormant ball. This is intended to hit the club face optimally in order to transfer the impact pulse from the racket to the ball. With an optimal impact, the striking surface should be guided in such a way that the ball strikes approximately in the region of the longitudinal axis of the racquet. On the other hand, if the ball gets into the outer area of the clubface or possibly even on the racket's frame, this results in significantly increased torques to be absorbed by the user's hand on the handle of the club.

The player must counteract these additional forces by making the muscles of the hand of his striking arm stronger to increase the holding force with which his hand encloses the grip. Such an increased holding force can lead to an incorrect loading of the arm muscles of the beating arm, as a result of which tension or epicondylitis, up to chronic inflammations of the arm muscles, which are also referred to as tennis elbow or epicondylitis, can occur.

As part of training to improve stroke technique, therefore, an important learning objective is that a practitioner learns to hit the ball within a suitable clubface and to enclose the club or handle with a suitable holding force that is individually dependent on the player's constitution , In particular, the ball learning players embrace the stick too tight; These should be trained the optimal holding force for fixing the racket.

From DE 39 29 459 Al a tennis racket is known, in which in the cavity of the handle, a holding force measuring device is installed, by which enclosing the handle Holding force can be determined. If the set limit value of the holding force is exceeded, an acoustically perceptible signal is produced.

The disadvantage here, however, that the installation of the force measuring device in the grip of the known tennis racket requires a special and complex processing. Thus, depending on the design of the force-measuring device, splitting of the handle into two parts which can be reassembled as well as a subsequent mechanical balancing of an unstable system, which is made up of several tension springs, is required.

Retrofitting commercial racket with the holding force measuring device according to the prior art is therefore at least extremely time consuming and therefore expensive. The hitherto known solution can usually then be used when a specially made training tennis racket is to be used in advance. The holding force measuring device can not be arbitrarily inserted and removed in the rackets to use this with or without the force measuring device, because the assembly is technically complicated.

Since the acoustic signal is generated only at the time of each beat, the player can not detect a long-term change in the applied holding power, namely, when the signal is triggered only when a limit is exceeded.

The structural design of the holding force measuring device according to the prior art consists of a plurality of components, in particular of springs, and encoders, which are electrically connected to each other. The assembly of such components is difficult and can only be made due to special expertise.

It is therefore an object of the invention to provide an improved grip for a sports equipment, by which the striking technique can be optimized while playing with the sports equipment.

This object is achieved by the features of the claims. The present invention provides a handle for a sports device, particularly for a tennis, squash, racquet, paddle tennis, badminton or golf club. The handle has a force measuring device attached thereto which is adapted to measure a force applied to the handle force applied by a player's hand enclosing the handle. Furthermore, the handle has an electronic evaluation unit, which is electrically connected to the force measuring device. In this case, the force measuring device has at least one flat trained force sensor or measuring sensor which is mounted on the handle so that the force transmitted from the player's hand can be measured by the force sensor.

According to a preferred embodiment, the at least one flat trained Kraftbzw. Measuring sensor mounted on the handle so that the force transmitted from the third, fourth and fifth fingers of the player's hand force can be measured by the force sensor. In this case, it is particularly preferred that the forces transmitted by the individual fingers, in particular by the third, fourth and fifth fingers, of the player's hand can each be measured independently of one another. This is for example possible because the force measuring device several force sensors, eg. B. three force sensors, which are placed so that the corresponding fingers of the player's hand come to rest on the individual sensors in a normal gripping the sports equipment.

According to a further preferred embodiment, the electronic evaluation unit is suitable for triggering an optical and / or acoustic signal. This can for example always be triggered when a certain predefmierte force is exceeded, or when the power transmission of the individual fingers on the handle is uneven.

It is further preferred that the measuring or force sensor consists of two layers, which are spatially separated from each other, for. B. by an intermediate element, are separated. In this case, the one layer of the force sensor can be firmly connected to a surface of the handle and the intermediate element can be pressed apart by a pressure force exerted on the second layer so that a switching contact forms when a certain presettable threshold value is exceeded with the first layer. This intermediate element may optionally be interchangeable and have a certain predetermined limit value, can be fixed by the threshold at which the first layer with the second layer of the force sensor forms the switching contact.

According to a further preferred embodiment, the evaluation unit is suitable for generating a signal in the form of a force display of the measured pressure value. For example, the force applied to the last beat can be displayed, for example. Alternatively or additionally, the evaluation unit can have a memory device by means of which the force values determined by the force sensors can be temporarily or permanently stored and from which these measured data can be visually retrieved. For example, after a training session, the entire course of the measured force during the session can be understood. As a result, for example, in the wake of a large number of bats, the forces applied in each case can be reconstructed in order to be able to judge the training progress. This is further facilitated if the signal transmitter has an optical display unit, for example a numerical display or a luminous dot or bar scale, by means of which the respective value of the holding force is represented graphically.

The force sensors may preferably be arranged on a handle side which runs parallel to the striking surface of the racket, since the fingers of the hand usually rest on a side of the handle parallel to the plane of the striking surface. As a result, it is possible in a simple manner to directly detect the holding force applied by the fingers of the hand, and thus also to derive essential information with regard to the force exerted for the respective executed stroke. This allows sufficient conclusions as to whether the ball to be hit has hit in the middle of the clubface or outside the optimum target area. However, this can vary from sports equipment to sports equipment and depends essentially on how the respective grip is usually enclosed by the player's hand.

The force sensor (s) are preferably housed in one or more recesses in the handle. The handle further preferably has a grip band and the at least one force sensor is arranged under this grip band. As a result, the sensor is protected on the one hand by the grip band, which on the other hand is flexible enough that the force to be measured can be transmitted to the sensor. The at least one force sensor is preferred covered by the grip band and fixed to the handle.

According to an alternative embodiment, the handle further comprises a handle shell, under which the at least one force sensor is arranged. Particularly preferably, the handle alternatively has two handle half-shells, under which the at least one force sensor is arranged. The two handle half-shells are spaced apart from each other and can be pressed against each other by the force applied by the player's hand. The two half-shells are by a force by means such as. As a spring, pressed apart and only come into contact with each other when the transmitted power from the player is sufficiently large. The force required for this purpose is preferably less than 40 N and is particularly preferably in a range between 5 N and 20 N.

The evaluation unit is preferably electrically connected to a power source and the evaluation unit and the power source are arranged in a common housing which is attached to or in the handle.

The force sensor is preferably designed as a strain gauge or as a capacitive or inductive proximity sensor or as a piezoelectric sensor. A preferred example of a piezoelectric sensor is polyvinylidene fluoride (PVDF). However, other force sensors can also be used.

The present application further relates to a sports equipment, in particular a tennis, squash, racquet, Paddletennis-, badminton or golf clubs, with a handle as described above.

With reference to the figures, preferred embodiments of the invention will be explained in more detail below. In detail show:

1 shows a tennis racket with a mounted on the handle force measuring device consisting of four measuring sensors through which the holding force acting on the handle can be determined, in plan view,

2 is an enlarged view of the handle of FIG. 1, 3 shows the handle according to FIG. 2 along the section line III-III, FIG.

4 is an enlarged view of the handle with a supported on this measuring sensor in a different type of embodiment,

Fig. 5a shows a preferred embodiment of the handle according to the invention in perspective item view, and

Fig. 5b shows a variant of the embodiment of Fig. 5a in a perspective view.

From Fig. 1, a device 1 can be removed, through which the beating technique for the use of a tennis racket 2 can be optimized. In certain ball sports, such as tennis, golf, squash or badminton, it is of considerable importance to hit the approaching or resting ball in a certain optimal hit area 7 with the bat 2 in order to optimally transfer the pulse to be transmitted by the bat 2 to the bat Transfer the ball and move it in a certain direction. If the ball is hit outside of the hit area 7, then an additional torque, depending on the distance of the impact point to the longitudinal axis 10 of the racket second

Although the following statements relate to a tennis racket 2. Any other embodiment of a racket 2 for a particular ball sport can be equipped with the inventive device 1 and the handle according to the invention as well.

The racket 2 consists of a frame 3, at one end face of a handle 4 is attached, which has a cavity 5 and the other end face is designed as an ellipse. In the area of the ellipse a covering 6 is provided between the frame 3, which serves as a total hit area. The hatched area of the clothing 6 extending along the longitudinal axis 10 represents the optimum impact area 7 on which the ball should preferably impinge in order to optimally transfer the impact impulse generated by the racket 2 to the ball, without the holding force required being unnecessary is increased.

If the ball impinges on the fabric 6 or even the frame 3 outside of the optimal impact area 7, an additional torque is generated, which is to be supported by the player by means of an additionally applied holding force which acts on the grip 4. In order to determine this additional holding force, the device 1 according to the invention is provided, which consists of a force measuring device 11 and an evaluation unit 16. In the exemplary embodiment shown, the force-measuring device 11 comprises a total of four force or measuring sensors 12 which, according to FIGS. 2 and 3, are mounted opposite one another on the surface 8 of the handle 4.

The measuring sensors 12 thus run parallel to the longitudinal axis 10 of the racket 2 and are thus arranged to extend parallel to the impact plane formed by the covering 6. Namely, the player grasps the grip 4 such that the third, fourth and fifth fingers of his hand support the grip 4; the thumb and forefinger of the hand serve as guides or as abutments to the holding force applied by the third, fourth and fifth fingers.

The holding force is thus transmitted directly to the handle 4 by the third, fourth and fifth fingers of the hand. In order to optimally determine this application of force to the handle 4, the measuring sensors 12 are assigned exactly to the positions of the third, fourth and fifth fingers, in such a way that the racket 2 can be used as usual. Each pressure force applied by these three fingers is thus detected by the measuring sensor 12 arranged in this position. The determined force values are forwarded to the evaluation unit 16 via an electrical connection between the measuring sensor 12 and the evaluation unit 16.

The evaluation unit 16 can be assigned a memory unit, by means of which the force measured values determined in this way are collected and stored during a large number of beats to be executed. After completion of the training game, the measured values can be visualized on a display 18 in the form of numerical values or by bar graphs. The player thus receives a possibility of comparison between the individual punches and the holding forces of the racket 2 used for this purpose. Furthermore, the evaluation unit 16 with a light emitting diode 19 and / or an acoustic signal generator, z. B. a horn 20 may be connected. Namely, if it is desired that a signal in visual and / or acoustic form is to be present when a certain preset limit value of the holding force is exceeded, the light emitting diode 19 or the horn 20 is activated by the evaluation unit 16, so that the player immediately after executing the respective stroke has a control of the impact force used.

In FIGS. 2 and 3, the measuring sensor 12 consists of a plate 4 integrated in the handle 4, which is inserted in a recess 22 incorporated in the handle and of an upper plate movable in the direction of the lower plate of the measuring sensor 11. For example, as soon as the upper plate of the measuring sensor 12 comes into contact with the lower plate against the force of a spring, a switching signal is produced which is stored or evaluated by the evaluation unit 16. At the same time, the distance between the two plates can also be detected by the evaluation unit 16. The respective distances of the two plates of the measuring sensor 12 relate to the force acting on the handle 4 holding force. The closer the plates are compressed by the holding force of the player, the greater is the applied holding force. The outer plate of the measuring sensor 12 is thereby fixed by means of a grip band 9 on the handle 4. Since the grip band 9 is usually elastic, the holding forces acting on it are transmitted directly to the measuring sensor 12.

Furthermore, it is provided that the evaluation unit 16 together with a power supply unit, for. B. an accumulator 17, housed in a housing 21. The geometric dimensions of the housing 21 are designed such that it is inserted into the cavity 5 of the handle 4 and locked in this. Accordingly, the housing 21 can easily be removed from the racket 2 in a simple manner, so that the racket 2 can be used at the same time for tournament and training purposes.

FIG. 4 shows a different embodiment of the force or measuring sensor 12. The measuring sensors 12 each consist of a first layer 13 and a second layer 14, which are arranged one above the other in alignment. The first layer 13 is for example attached by means of an adhesive on the surface 8 of the handle 4. The outwardly facing surface of the first layer 13 is configured wave-shaped. Between the first and the second layer 13 and 14, an intermediate element 15 is provided. These may be, for example, individual liquid droplets enclosed in separate casings, which are pressed apart from the holding force acting on the second layer 14, so that a switching contact in the form of a contact arises in some areas between the first and the second layer 13, 14. The intermediate element 15 can be exchanged and has different densities of liquid drops, by means of which the degree of hardness of the intermediate element 15 can therefore be changed. Depending on how many drops of liquid are present that form the intermediate element 15, a greater compressive force acting on the second layer 14 is necessary to force the drops of the intermediate element 15 apart and thus to effect the switching contact with the first layer 13 ,

The first layer 13 is placed directly on the surface 8 of the handle 4; an additional technical measure for attaching the measuring sensor 11 is not necessary for this embodiment variant, whereby the assembly and disassembly is considerably simplified.

The evaluation unit 12 and the power source 17 may be arranged together with the housing shell 21 supporting this same between the impact surface 6 and the handle 4 in the V-shaped frame 6, as shown in FIG. 1 can be removed.

In Fig. 5 a, a further preferred embodiment of the erfmdungs proper handle is shown in perspective detail view. The handle 4 consists in this embodiment of two handle half shells 4a and 4b and an inner grip shaft or handle core 4c. The two handle half-shells 4a and 4b enclose the grip core 4c, whereby they preferably contact them in a force-locking manner. Between the handle half shells 4a, 4b and the handle core 4c and preferably on the handle core 4c, a sensor film is mounted, which serves as a force sensor 12.

According to a preferred embodiment, the sensor film 12 comprises polyvinylidene fluoride on. In principle, however, all known materials which are suitable for force measurement are suitable for the sensor film 12.

Only one sensor foil 12 can be provided between the handle core 4c and the upper handle half shell 4b. However, the handle 4 preferably has two sensor films 12, wherein a sensor film between the handle core 4c and the upper handle half-shell 4b and another sensor film between the handle core 4c and the lower handle half-shell 4a is attached. Although the sensor sheet 12 is attached to the handle core 4c in Fig. 5a, it may alternatively be attached to the handle half shells 4a and 4b.

The two handle half-shells 4a and 4b are preferably spaced apart from each other in the fully assembled handle 4 and can be pressed against one another or pressed against each other by the force transmitted by the player.

It is further preferred that a spring element is mounted between the two handle half-shells. Such a preferred variant of the embodiment of Fig. 5a is shown in Fig. 5b. In Fig. 5b, the items of Fig. 5a are seen joined together. However, in this preferred variant, a gap or gap 30 is created between the grip half-shells. In this case, a spring element, for example a rubber layer, is preferably introduced. In this way, the handle half shells 4a and 4b can be pressed against each other against the elastic restoring force of the rubber layer, with a force on the sensor film (s) 12 is applied.

The material of the rubber layer or of the elastomer between the grip half-shells is preferably selected such that a predetermined force is necessary to compress the grip shells sufficiently far enough for the sensor film (s) to register a force. The predetermined force is preferably less than 40 N, preferably between 5 and 20 N.

Claims

claims

A handle (4) for a sports equipment (2) having a force measuring device (11) attached to the handle (4) and capable of measuring a force acting on the handle (4) from a handle (4) ) and an electronic evaluation unit (16), which is electrically connected to the force measuring device (11), wherein the force measuring device (11) has at least one flat trained force sensor (12) on the handle (4) in such a way is attached that the transmitted from the player's hand force from the force sensor

(12) can be measured.

2. Handle according to claim 1, wherein the at least one flat trained force sensor (12) on the handle (4) is mounted such that the transmitted from the third, fourth and fifth fingers of the player's hand force from the force sensor (12) can be measured.

3. Handle according to claim 1 or 2, wherein the forces transmitted by the individual fingers, in particular by the third, fourth and fifth fingers, the player's hand can each be measured independently of one another.

4. Handle according to one of the preceding claims, wherein the electronic evaluation unit (16) is adapted to trigger an optical and / or acoustic signal.

5. Handle according to one of the preceding claims, wherein the force sensor (12) consists of two layers (13, 14), which are spatially separated from each other by an intermediate element (15).

A handle according to claim 5, wherein the one layer (13) of the force sensor (12) is fixedly connected to a surface (8) of the handle (4) and the intermediate element (15) by a compressive force exerted on the second layer (14) is auseinanderdrückbar and when exceeding a certain presettable threshold with the first layer

(13) forms a switching contact.

7. Handle according to claim 6, wherein the intermediate element (15) is optionally interchangeable and the intermediate element (15) has a certain predetermined limit by which it can be determined at which threshold the first layer (13) with the second layer (14) of Force sensor (12) forms the switching contact.

8. Handle according to one of the preceding claims, wherein the evaluation unit (16) is adapted to generate a signal in the form of a force display of the measured pressure value.

9. Handle according to one of the preceding claims, wherein the one or more force sensors (12) is arranged on a handle side / which is parallel to the impact surface (6) of the racket (2).

10. Handle according to one of the preceding claims, wherein the handle (4) has one or more recesses (22) in or in which the respective force sensor (12) can be inserted.

11. The apparatus of claim 10, wherein the evaluation unit (16) with a power source (17) is electrically connected and the evaluation unit (16) and the power source (17) in a common housing (21) are arranged on or in the handle (4) is attached.

12. Handle according to one of the preceding claims, wherein the evaluation unit (16) has a memory device by means of which the forces of the force sensors (12) determined force values can be temporarily or permanently stored and from which these measurement data are visually retrievable.

13. Handle according to one of the preceding claims, wherein the force sensor (12) is designed as a strain gauge or as a capacitive or inductive proximity sensor.

14. Handle according to one of the preceding claims, wherein the handle (4) further comprises Has grip band (9) and the at least one force sensor (12) under the grip band (9) is arranged.

15. Handle according to claim 14, wherein the at least one force sensor (12) covered by the grip band (9) and fixed to the handle (4).

16. Handle according to one of the preceding claims, wherein the handle further comprises a handle shell and the at least one force sensor (12) is arranged under the handle shell.

17. Handle according to one of the preceding claims, wherein the handle further comprises two handle half-shells and the at least one force sensor (12) is arranged under the handle half-shells.

18. Handle according to claim 17, wherein the two handle half-shells are spaced apart and can be pressed by the force applied by the hand of the player force to each other.

19. Sports equipment, in particular tennis, squash, racquet, Paddletennis-, badminton or golf clubs, with a handle according to one of claims 1 to 18.