WO1994017870A1

WO1994017870A1 - Biosensor feedback device for sporting implements

Info

Publication number: WO1994017870A1
Application number: PCT/US1994/001548
Authority: WO
Inventors: Maynard A. Howe, Jr.; Jeffrey M. Eliason
Original assignee: Sensagrip, Inc.
Priority date: 1993-02-11
Filing date: 1994-02-10
Publication date: 1994-08-18
Also published as: AU6174494A; JPH08509622A

Abstract

A biosensor feedback device for use in detecting grip pressure of a hand against the handle of a sporting implement (12). The device includes a flexible thin film substrate which is comfortable to the handle of the sporting implement (12), and an array of digital pressure sensors disposed on the flexible substrate (20). The sensors are connected to a signal, such as a buzzer (40), that indicates detection of pressure exceeding a desired threshold. The array of sensors can be divided into two or more sub-arrays of sensors and each of the sub-arrays can be connected to or disconnected from the signal as desired. Preferably sensors within each sub-array have generally uniform pressure sensitivity, and sensors of different sub-arrays have different levels of sensitivity. Thus, by connecting the sub-arrays having the desired level of pressure sensitivity the device can be adapted to provide feedback of a particular level of pressure exerted on the handle of the sporting implement (12).

Description

BIOSENSOR FEEDBACK DEVICE FOR SPORTING IMPLEMENTS FIELD OF THE INVENTION

The invention relates to a biofeedback device usable in conjunction with sporting implements, such as golf clubs, tennis rackets, baseball bats, firearms, and the like. In particular, the invention provides biofeedback to the user of the implement regarding the amount of pressure being exerted on the handle of the implement.

BACKGROUND OF THE INVENTION In a variety of sports, such as golf, tennis, baseball and the like, a person's grip on the handle of the club (or other sporting implement) can be critical to the degree of success the person has in the sport. For example, in golfing, many golfers are unable to consistently produce a smooth swing without jerking or otherwise changing strength of their grip mid-swing. Such jerking or changes in grip (or strength of grip) disrupt the smooth flow of a swing, causing the golfer to slice, hook, or otherwise inaccurately hit the ball. Conversely, players who are able to avoid such dysfunctions in their swing are able to more consistently hit the ball accurately.

Similar smoothness of stroke is desirable in many other sports utilizing hand-held implements, such as tennis rackets, baseball bats, and the like, and even firearms (where the sportsman frequently may jerk when pulling the trigger or prematurely move the firearm in anticipation of the firearm's natural recoil when discharged). Thus, in many such areas of sporting, there is a need for a biofeedback device which will signal to the sportsman significant changes in the sportsman's grip (or strength of grip) on the handle of the sporting implement being utilized.

Devices attempting to fill this need have been proposed. For example, U.S. Patent No. 3,323,367 (R.W. Searle) describes a "grip indicator" having a pair of resistive sensors connected in a conventional bridge circuit to a zero- centered ammeter mounted on the shaft of a golf putter. One of the pressure sensitive resistive sensors is located on the handle in a position corresponding to the left hand position of the golfer, and the other sensor is positioned for the right hand. By viewing the position of the needle on the ammeter, the golfer can visually confirm that his grip is equally balanced between his two hands. Although the invention is also described as being applicable to tennis racket handles, the utility of the device is somewhat limited by the need for the sportsman to actually view the position of the needle on the ammeter during use of the putter/racket. This limitation significantly affects the utility of the device when used other than in gentle strokes (such as with a putter).

U.S. Patent No. 4,138,118 (D.R. Budney) provides an improvement over the Searle indicator, in that Budney connects two or three analog pressure-sensitive transducers to a chart recorder which graphically depicts the amount of force being exerted on each pressure transducer during the swing of a golf club. The devices uses two, or, at most, three transducers on the handle of the club, independently charting the force applied to each such transducer. Analysis of the printout of the chart recorder reveals the faults in the player's swing, permitting after-the-fact diagnosis of the swing. The device does not provide real time feedback to the golfer, however, and requires an electrical cable connecting the club to a portable chart recorder, making the device somewhat cumbersome to utilize.

U.S. Patent No. 4,861,034 (S.Y. Lee) describes a grip training device attachable to (and removable from) the handle of a golf club. An elongated pressure sensitive switch is mounted on the underside of the handle, and is responsive to the grip pressure of the golfer. The switch is formed of three resilient conducting strips spaced from one another by compressible foam blocks. When grip pressure is sufficient to compress one of the resilient, conducting strips against an adjacent strip, a circuit is completed causing a battery powered buzzer to emit an audible signal. The Lee device is relatively thick in relation to the thickness of a golf club handle, and consequently affects the normal grip of the golfer. Moreover, the device provides pressure sensing only on the underside of the club handle, and therefore cannot detect pressure of the golfer's hands against other portions of the handle.

In addition to the above referenced patents, other similar biofeedback devices have been proposed. In most cases, however, such devices are complicated to use, interfere with ordinary grip and/or use of the sporting implement, and/or are quite expensive.

SUMMARY OF THE INVENTION The invention provides a relatively simple, versatile biosensor feedback device for use in detecting grip pressure of a hand against a handle of a sporting implement. The device utilizes an array of digital pressure sensors which is carried on a thin film flexible substrate that is conformable to the handle of the sporting implement. Means is provided for securing flexible substrate to the handle, and signal means is electrically connected to the array of sensors for signalling to the sportsman, in real time, the detection of a grip pressure exceeding a preselected level. In a preferred embodiment, the array of sensors includes two or more sub- arrays of sensors, each sub-array being configured to detect a different preselected level of grip pressure, and each such sub-array being selectively (and independently) connectable to the signal means. In this way, the sportsman can select which level(s) of pressure sensitivity will be detected. Desirably, sensors corresponding to each of the sub-arrays are generally uniformly distributed throughout the overall array, and desirably, that portion of the sporting implement handle which is typically contacted by the sportsman's hand(s) is generally uniformly covered by the array of sensors.

In a preferred embodiment, each pressure sensor comprises an electrical, pressure sensitive switch. Each such switch includes a first flexible conductive path carried on a first thin film substrate, and a second flexible conductive path carried on a second thin film flexible substrate. The second conductive path is aligned with the first conductive path, and spacer means is provided for normally spacing the first conductive path away from the second conductive path. The spacer means is sized and located so as to permit the second conductive paths to contact the first conductive path when pressure exceeding a selected level is exerted on the portion of the second flexible substrate carrying the second conductive path. Using such thin film technology, an array of such switches can be easily manufactured to be less than 0.1 inches thick (including the thickness of the substrates)~desirably the switches are not more than about 0.03 inches thick, and most preferably, the switches are less than about 0.015 inches thick. Such thin film switches therefore add only an insignificant thickness to the handle of the implement, and do not interfere with the sportsman's normal grip. Moreover, they can be manufactured quite economically.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a golf club on which has been mounted a biosensor feedback device of the invention;

Figure 2 is a perspective view of one embodiment of the device of the invention;

Figure 3 is an exploded, plan view of the device of Figure 2; Figure 4 is an electrical schematic diagram of a preferred embodiment of the invention;

Figure 5 is an exploded, perspective view of a preferred embodiment of the invention;

Figure 6 is a cross-sectional view of the embodiment of Figure 5, taken along line 6-6 thereof; Figure 7 is a plan view of a flexible metal circuit usable in the device of the invention; and

Figures 8-10 are plan views of various spacer patterns usable in connection with the device of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION Although the drawings illustrate the invention in connection with use on the handle of a golf club, as indicated above the invention is suitable for use in connection with any sporting implement having a handle normally gripped by the sportsman, including, without limitation, golf clubs, tennis rackets, baseball bats, Softball bats, racquet ball rackets, and the like, as well as firearms. The utility, and therefore applicability, of the invention will be found wherever it is desired to train a sportsman to utilize a grip of generally constant strength. Figure 1 depicts the apparatus of the device secured to the handle 12 of a golf club 10 by a spiral wrapping material 14. Figure 2 depicts in larger, somewhat schematic fashion, the biosensor feedback device of the invention, which includes an array 20 of sensors 22 carried on a flexible, thin film substrate 21. A biofeedback signal device, designated generally as 40, is secured to the shaft of the golf club 10 by a suitable collar or band 41, and is electrically connected to the array 20 of sensors 22 by conventional means.

The layout and configuration of the sensor array 20 on a flexible substrate 21 may vary from one application to another. Figure 3 shows a plan view, somewhat schematically, of the sensor array depicted in Figures 1 and 2~the array being sized so as to substantially completely cover the handle of the golf club with generally uniformly spaced sensors 22 when the array is wrapped around the handle of the club. Alternate configurations could also be utilized for the golf club, as well as for other sporting implements. For example, the array could comprise an elongated strip (such as is shown in Figure 7) with a series of sensors in a one-dimensional array. Such a strip could be helically wound around the handle of a golf club, tennis racket, baseball bat, etc., to provide the desired coverage of the handle with sensors. Alternately, two or more such strips could be disposed in parallel fashion along the length of the handle of such a sporting implement. Various other suitable configurations could also be utilized. The primary objective to be achieved in configuring such an array is substantially uniformly covering that portion of the handle of the sporting implement which will be gripped by the sportsman.

Figure 5 depicts in exploded, broken-away fashion a preferred construction of the sensor array. In this preferred embodiment, each sensor comprises a digital switch which is normally open and is closed in response to grip pressure exceeding a preselected level. Such switches can be constructed utilizing flexible thin film printed circuits. Typically, the switch constructed in this fashion includes two thin, flexible substrates, each carrying conductive paths aligned with one another. The substrates are spaced a short distance from one another by a preferably rigid spacer. The size, thickness, and positioning of the rigid spacer(s), as well as the flexibility of the outer of the two substrates, dictates the amount of force required to deflect the outer substrate toward the inner substrate, thus allowing the conductive traces to touch, completing an electrical circuit. Providing digital switches of this type gives the device significant advantages over prior art analog sensors (such as those utilized in the Budney and Searle patents identified above), in that the circuitry required is extremely simple. Multiple switches of the type described can be connected in parallel to a small battery which in turn is connected to a low voltage signal, such as a piezoelectric buzzer. No further signal processing equipment is needed.

In the particularly preferred embodiment of Figure 5, a preferred construction for the thin film digital switches is illustrated. A first, base substrate 21 (preferably polyester or similar flexible substrate material commonly utilized in flexible circuits) carries a flexible metal circuit manufactured utilizing conventional flexible circuit manufacturing techniques. Typically, the first substrate 21 is approximately 0.03-0.04 inches thick, and carries a layer of tinned copper having a thickness of about 0.001 inches. The metal traces include a plurality of switch portions 22 which consist of a break or discontinuity in the circuit. An upper or top substrate 47 (typically polyester film of about 0.003-0.007 inches thick— most preferably about 0.005 inches thick) carries a plurality of flexible, very thin conductive patches 49. These patches may be made of any suitable conductive material, and preferably are a flexible carbon conductive material. The conductive patches 49 are positioned in alignment with the discontinuity in the switch portions

22 of the copper traces.

A thin film of a suitable flexible adhesive 33 secures the two substrates 21 and 47 to each other, the adhesive having openings 34 therein so as not to insulate the conductive patches 49 from the switch portions 22 of the metal traces. Means must be provided for assuring that the conductive patches 49 do not normally contact the switch portions 22 of the conductive traces. Since the switch portions 22 of the conductive traces desirably are many times wider than they are thick (so as to provide a thin film switch that covers a significant portion of the surface area of the array), it is desirable to have the spacer(s) disposed directly between the patch and switch portion of the traces. Accordingly, in a preferred embodiment, a pattern of rigid spacers 36 is disposed across substantially the entire area of each conductive patch 49, and, desirably, the pattern extends slightly beyond the conductive patch/switch portion of the conductive traces. The pattern may be of a variety of shapes, configurations and thicknesses to give the desired spacing between the patch and the electrical traces. Preferably the material utilized is flexible but substantially incompressible. A U.V. cured ink material, screened onto the upper substrate 47 (after the conductive patches 49 have been applied to the substrate 47) with a thickness on the order of 0.001 inches has worked well.

The thickness and flexibility of the outer substrate 47 and the size and thickness of the rigid spacer pattern 36 together determine the amount of force necessary to deflect the substrate 47 sufficiently to allow contact of the conductive patch 49 with a switch portion 22 of the conductive traces. This level of force can be selected as desired for the particular application at hand. In tennis and baseball, forces in the range of 25-35 psi are frequently desirable; in golf, the forces are typically somewhat less, e.g., in the range of 20-25 psi. In terms of direct force, Applicant has found that a force of approximately 0.2-0.3 lbs., e.g., as measured by a 3/4 inch artificial "finger" made from 45 durometer silicone, provides a useful switch threshold.

Although all of the sensors in an array could be of the same force threshold, desirably the array includes at least two or, preferably, three sub-arrays, each for switches of different force thresholds (typically varying from one another by 10% -200%). Utilizing switches of multiple sensitivities (and permitting the sportsman to select which of these sub-arrays of switches is activated at a given time), allows great versatility in use of the device in varying situations. For example, the grip of a golfer on a putter is typically much lighter than the desired grip on a driver. Thus, when the device is utilized on the handle of a putter, switches activated with only a small amount of force can be selected, whereas when utilized on the handle of a driver, the golfer can select only switches requiring a larger amount of force.

Figure 6 illustrates a cross section of one of the switches (though not to scale, due to the thinness of the materials). The adhesive layer is not shown for purposes of clarity.

Figure 4 illustrates schematically an exemplary circuit for a device utilizing three sub-arrays, corresponding to three sets of sensors uniformly distributed over the handle of the sporting implement. A battery 44 is connected in series with a signal device 42 (such as a piezoelectric buzzer). Power switch SW1, when closed, enables the device. Selector switches SW2, SW3, and SW4 can be closed, as desired by the sportsman, to selectively activate any one or two of the sub- arrays, or all three arrays, as desired. The four switches may simply be conventional dip switches, which can be easily manipulated by the point of a golfing tee, or similar readily available device or tool, and these dip switches, the battery and the buzzer may be easily packaged in a very small enclosure (identified generally as 40). When switch SW2 is closed, sub-array 24 is enabled. Similarly, when switch SW3 or switch SW4 is activated, sub-arrays 25 and 26, respectively, are enabled. When any one of the switches 22 in an enabled sub-array is closed, the electrical circuit is completed, and buzzer 42 emits an audible signal, alerting the sportsman to the fact that excess pressure has been applied. Since the signal is perceived by the sportsman in real time, the sportsman can immediately identify what portion of the stroke is causing the problem (e.g., the back swing, just prior to hitting the ball, etc.).

Figure 7 depicts one example of a circuit pattern where an elongated, one- dimensional array of sensors is utilized. The contacts at the top of the pattern are suitable for being plugged directly into a zero-insertion-force type of socket; other types of conventional connectors, including male/female type plugs, may also be utilized.

It will be appreciated that a variety of suitable circuit patterns could be utilized. For example, although the drawings generally depict substantially all of the circuitry carried on the lower substrate (the switch portions of the circuit comprising discontinuities which are bridged by the conductive patch on the opposing substrate), significant portions of the circuit could also be carried by the upper substrate 47. For example, conductive circuits on the lower substrate 21 could be juxta-posed across from complimentary traces on the upper substrate 47 which in turn are connected back to the signal means 40, the two sets of conductive paths being insulated from one another except for portions where they are juxta-posed across from one another to define a switch/sensor portion of the array. Other suitable configurations may also be utilized.

Figures 8-10 depict several variations of sizes and configurations for the rigid spacers disposed between the conductive patches 49 and the switch portions 22 of the flexible circuit. Each of these figures depicts a series of patterns that would be useful in conjunction with the circuit illustrated in Figure 7, i.e., a linear array of twelve switches, the array being composed of three sub-arrays a, b, and c. Each of the sub-arrays has four switches with substantially identical pressure detection levels, and switches of the three sub-arrays are placed in the linear pattern "abcabcabcabc". In each case, the rigid spacer pattern 36b is a pattern that gives a switch a "medium" level of pressure sensitivity; the spacer pattern 36c has slightly wider spacing, thus giving the switch a slightly higher level of sensitivity (i.e., with spacers further apart, it is easier to deflect the outer substrate sufficiently to cause contact of the opposing conductive materials to complete the circuit); and the spacer pattern 36a has a slightly narrower spacing giving the switch a slightly higher level of sensitivity (i.e. , making it more difficult to deflect the outer substrate). Thus, in Figure 8, a series of dot-shaped spacers is illustrated, the bottom pattern having spacers 36a, the next pattern having spacers 36b of slightly farther apart, and the next pattern having spacers 36c even farther apart. The central "star" in each of these patterns represents schematically the location conductive carbon patch 49. In Figure 9, rather than dots, the spacers comprise elongated strips 36a', 36b'and 36c', the strips being of varying widths. In Figure 10, the spacers comprise a cross-hatch pattern 36"a, 36"b and 36"c. Other suitable patterns could also be utilized. In use, the sportsman attaches the flexible substrate (with its array of sensors) to the handle of the sporting implement being utilized. Such attachment may be by an adhesive on the back of the flexible substrate, by wrapping a thin layer of hand grip material (such as plastic or thin leather) around the device (as shown in Figure 1), by placing an elastic sleeve over the device or by any other suitable means. The sportsman then attaches the signal device 40 by clipping it to the shaft of the handle and plugging it into the circuit carried on the flexible substrate. If the signal device is equipped with switches for enabling/disabling sub-arrays of sensors, the desired switches are selected to give the desired sensitivity to the device. (Alternately, a signal device 40 pre-set to automatically connect only to the desired sub-array(s) may be selected and mounted on the handle, the sportsman having several such signal devices each pre-set to automatically connect to a particular sub-array or set of sub-arrays.) The sportsman then uses the sporting implement in its ordinary fashion; if, during such use, pressure exceeding the selected threshold is exerted, the signal will go off, indicated such excess pressure. If the sportsman desires to change the sensitivity of the device, the selection switches can be manipulated to enable/disable the sub- arrays as desired (or, alternately, the signal device can be replaced with another signal device which is pre-set to automatically connect to the desired sub-array(s) of switches). While a preferred embodiment of the present invention has been described, it should be understood that various changes, adaptations and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A biosensor feedback device for use in detecting a grip pressure of a hand against a handle of a sporting implement, comprising: a flexible thin film substrate, being conformable to the handle of the sporting

implement; an array of digital pressure sensor means disposed on the flexible substrate for detecting grip pressure exceeding a selected level; attachment means for securing the flexible substrate with the digital pressure sensor means to the handle of the sporting implement; and signal means electrically connected to the array of digital pressure sensor means for signalling the detection of grip pressure exceeding the selected level.

2. The device of claim 1 wherein the array of pressure sensor means includes two or more sub-arrays of pressure sensor means.

3. The device of claim 2, 17 further including switch means for selectively enabling each of the sub-arrays.

4. The device of claim 1 wherein the array of pressure sensor means includes two or more sub-arrays of pressure sensor means, each sub-array having a plurality of pressure sensor means detecting a level of pressure different from the pressure level detected by pressure sensor means of the other sub-array (s).

5. The device of claim 4 wherein the pressure sensor means of each sub-array are generally uniformly distributed throughout the array of pressure sensor means.

6. The device of claim 4 further including switch means for individually selectively enabling each of the sub-arrays of pressure sensor means.

7. The device of claim 1 wherein at least some of the digital pressure sensor means comprise pressure sensitive switches.

8. The device of claim 7 wherein each such pressure sensitive switch

comprises a first flexible electrically conductive path carried on the first thin film substrate, a second flexible substrate carrying a second flexible electrically conductive path thereon in registration with the first conductive path, and spacer means for normally spacing the first conductive path from the second conductive path, the spacer means permitting the second conductive path to contact the first conductive path when pressure exceeding a selected level is exerted on the portion of the second flexible substrate carrying the second conductive path.

9. The device of claim 8 wherein the first conductive path comprises a first pattern of conductive traces having a conductive discontinuity therein, and the second conductive path is aligned with the conductive discontinuity to bridge such discontinuity when the pressure exceeding the selected level is exerted on such portion of the second flexible substrate carrying such second conductive path.

10. The device of claim 8 wherein the total thickness of each such pressure sensitive switch is not more than about 0.1 inches.

11. The device of claim 8 wherein the total thickness of each such pressure sensitive switch is not more than about 0.03 inches.

12. The device of claim 8 wherein the total thickness of each such pressure sensitive switch is not more than about 0.015 inches.

13. The device of claim 8 wherein the spacer means comprises a relatively incompressible spacer disposed between the two flexible substrates.

14. The device of claim 9 wherein the rigid spacer comprises a pattern of discreet, substantially incompressible spacer elements disposed between portions of the first and second conductive paths.

15. The device of claim 1 wherein the array of pressure sensor means is generally uniformly spaced over the substrate and the substrate is configured to substantially cover that portion of the sporting implement handle gripped by the hand.

16. A biosensor feedback device for use in detecting a grip pressure of a hand

against a handle of a sporting implement, comprising: first and second flexible substrates, each being generally conformable to the handle of the sporting implement; an array of digital pressure sensor switches disposed between the flexible substrates for detecting grip pressure exceeding a selected level, each such switch comprising a first flexible conductive path carried on the first substrate, a second flexible conductive path carried on the second flexible substrate in registration with the first conductive path, and substantially incompressible spacer means disposed between the first and second substrates for normally spacing the first conductive path from the second conductive path, the spacer means permitting the second conductive path to contact the first conductive path when pressure exceeding a selected level is exerted on the portion of the second flexible substrate carrying the second conductive path;

attachment means for securing the flexible substrates with the digital pressure sensor means to the handle of the sporting implement; and signal means electrically connected to the array of digital pressure sensor switches for signalling the detection of grip pressure exceeding the selected level.

17. The device of claim 16 wherein the array of pressure sensor means includes two or more sub-arrays of pressure sensor, means.

18. The device of claim 17 further including switch means for selectively

enabling each of the sub-arrays.

19. A biosensor feedback device for use in detecting a grip pressure of a hand against a handle of a sporting implement, comprising: a flexible thin film substrate, being conformable to the handle of the sporting

implement; an array of digital pressure sensor means disposed on the flexible substrate for detecting grip pressure exceeding a selected level, the array being comprised of two or more sub-arrays of pressure sensor means, the pressure sensor means of each sub-array being generally uniformly distributed throughout the array of pressure sensor means; switch means for selectively enabling each of the sub-arrays of pressure sensor means individually; attachment means for securing the flexible substrate with the digital pressure sensor means to the handle of the sporting implement; and signal means electrically connected to the array of digital pressure sensor means for signalling the detection of grip pressure exceeding the selected level.

20. A biosensor feedback device for use in detecting a grip pressure of a hand against a handle of a sporting implement, comprising: a flexible thin film substrate, being conformable to the handle of the sporting implement; an array of digital pressure sensor means disposed on the flexible substrate for detecting grip pressure exceeding a selected level, the array being comprised of two or more sub-arrays of pressure sensor means;

attachment means for securing the flexible substrate with the digital pressure sensor means to the handle of the sporting implement; and signal means electrically connected to one or more of the sub-arrays of digital pressure sensor means for signalling the detection of grip pressure exceeding the selected level.

21. The device of claim 20 wherein the signal means is connected to the sub-

array (s) of pressure sensor means through a disconnectable electrical plug.

22. The device of claim 20 further comprising a plurality of signal means, each being connectable to a different one or more of the sub-arrays of pressure sensor means through such disconnectable electrical plug.

23. The device of claim 20 wherein the signal means is connected to the array of pressure sensor means through a plurality of electrical switches, each switch connecting the signal to at least one of the sub-arrays.