Impact sensing target
United States Patent [:91  
 Faurot et al.  
 [451 Apr. 1,1975  
 [ IMPACT SENSING TARGET [76] Inventors: William R. Faurot; Bjorn G.  
 Bjornsen, both of Whitefish Bay, Wis.  
 {22] Filed: Oct. 29, 1973 [21] Appl. No.: 410,889  
 [52] US. Cl 273/29 A, 273/1022 S, 273/181 .1 [51] Int. Cl A63b 63/00 [58] Field of Search 273/29 A, 26 A, 176 13, 273/18] R, 181 C, 181 G, 102 R43 R,  
 102.1 B, 102.1 C, 102.2 A, 102.2 B, 102.2 S,  
 181 .l, 181 K, 54 R; 340/261, 273, 384, 38  
 [56] References Cited UNITED STATES PATENTS 3.091.457 5/1963 Mentzer et al 273/54 R 3,163,856 12/1964 Kirby 340/26 X 3,415,517 12/1968 Krist 273/29 R X 3,790,167 2/1974 Lcnhart ct a1. 273/43 R 3,792,863 2/1974 Evans 273/186 A Primary Examiner-Richard C. Pinkham Assistant E.raminer T. Brown Attorney, Agent, or Firm-Daniel D. Fetterley [5 7] ABSTRACT A target for being positioned on a surface such that an object impinged thereagainst will deflect the target to generate a pulse which is transmitted to an indicator such as a horn, a light, a counter. etc. The target comprises a flat panel having a cavity therein and placed on a surface. The cavity is bridged by a diaphragm which is deflected when the target is hit by an object. Connected to the target is a transmitter such as an elongated tube. The other end of the transmitter is connected to the indicator. When the diaphragm is deflected by virtue of an object hitting the panel, a pulse is generated through&#39;the transmitter to the indicator. The transmitter and cavity are provided with a device which maintains ambient pressure therein.  
 17 Claims, 5 Drawing Figures IMPACT b \SIXU TARGET FlliLD OF THIZ INVFN&#39;I&#39;ION The present imention relates to a target capable of sensing impacting objects.  
 BACKGROUND AND SUMMARY OF INVENTION The present invention relates to a means for accelerating the learning of basic tennis skills. and more specifically. to a device which enables a tennis player to rapidly achieve and maintain a high level of accuracy in hitting tennis balls to selected areas of the court during both ser\ ice and play.  
  The invention consists of an impact sensing target having associated therewith a means for providing a prolonged and intensified visual or audible indication of the impact of a tennis hall on the target. It is well established that feedback indication of this nature accelerates learning and execution ofdesired behavioral patterns such as tennis skills. The target is placed at a de sired location on the tennis court and the player practices hitting balls toward the target. A number of targets may be placed at various locations on the court to enable the player to practice certain prescribed tactical hitting sequences. The size of the target area may be increased by employing a plurality of targets at each location.  
  In a preferred embodiment of the invention. the target includes a panel which is positioned on the tennis court. A cavity on the bottom ofthe panel is closed by a diaphragm having a foot abttttable with the tennis court. The cavity is coupled to a pneumatic electric transducer which in turn is coupled to an indicating means. When a tennis ball strikes the panel it causes a deflection of the diaphragm creating a pneumatic pulse for operating the transducer and the indicator.  
 BRIEF DESCRIPTION OF THli DRAWING FIG, I is a perspective view of a tennis court showing a typical use of the impact sensing target of the present invention.  
  Fl(i. 2 is a view of the underside of one embodiment of the impact sensing target of the present invention.  
 Fl(i. 3 is a cross sectional view taken along the line 33 of FI(J. 2 showing. in detail. the sensing means of the target.  
  Fl(i. 4 is a schematic diagram of an indicator means suitable for use with the impact sensing target of FIGS. 2 and 3.  
  FIG. 5 is a diagrammatic view of another embodiment of the present invention.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to FIG. I. there is shown therein a tennis court of standard dimensions and construction. Tennis court III includes a pair of forecourts I21! and I2!) and a baekcourt [4 on each side of the net I6.  
  The impact sensing target of the present invention is designed for placement on tennis court I0 to enable a tennis player to practice hitting tennis balls to desired locations.  
  As an example. it may be assumed that a player dcsires to practice service to the center corner of forccourt IZu. For this purpose. impact sensing target 18 is located at the center corner of said forecourt. Depending on the level of skill of the player. the target area may be increased by the use of a plurality of targets I8. as shown in dotted lines in I-l(i. I. Impact ensing target I8 is connected by tubing 20 to indicator 22 for indicating when the impact sensing target has been struck.  
  Impact sensing target 18 includes panel 24 liming a brightly colored upper surface 26 on which objects such as tennis balls impact and a lower surface 28 which is contiguous with tennis court HI when impact sensing target 18 is in use. Panel 24 is formed of material ofsulficicnt stiffness to resist the impact of the objects and to transfer such impact to the sensing means. Plywood. fa inch in thickness has been found suitable for this purpose. In order for impact sen ing target I8 to furnish sufficient practice incenti\ e or challenge. it has been found desirable to dimension panel 24 according to a predetermined ratio relative to the dimensions of tennis court It). For example. panel 2-3 may be dimensioned relativ e to the dimensions of the forecourt or baekcourt so that target l8 occupies a preselected fraction of these areas. It has been found that dimensioning panel 24 equal to approximately l/Sllth of the forecourt or baekcourt provides a target which relates well to intermediate through advanced levels of tennis skill while facilitating transportation and handling of the targets.  
 Four projections extend front lower surface 28 of panel 24 for supporting impact sensing target IS on the playing surface of tennis court II) when the target is in use. Three of these projections may comprise rubber pads 30 or other suitable resilient. non skid elements located adjacent three of the corners of panel 24. The fourth projection. located adjacent the remaining corner of panel 24. is sensing means 32.  
  Sensing means 32 includes cavity 34 shown in FIG. 3. (avity 34 may be formed in panel 24 by cutting out a disc ofthe panel. A diaphragm 36 is positioned across cavity 34 to seal the cavity into a chamber. Diaphragm 36 must be sufficiently stiff to support its share of the weight of panel 24 and to resist damage should target 18 accidentally he stepped on. ()n the other hand. diaphragm 36 must be sufficiently flexible to deflect upon ball impact to generate a pneumatic pulse. as hereinafter described. Stainless steel approximately H.006 inch thick has been found suitable for use as diaphragm 36. To position diaphragm 36 across cavity 34. ring 38 hav ing annular groove 40 for receiving diaphragm 36 may be placed over the diaphragm and the ring and diaphragm affixed to panel 24 by screws 42.  
  In the center of diaphragm 36 is mounted pad 44 which engages the playing surface of tennis court [0. Pad 44 is affixed to diaphragm 36 as by rivet 46. The depth of depression 48 is selected such that should panel 24 he stepped on. the upper surface of rivet will strike the bottom ofdepression 48 before excessive and possibly damaging deflection of diaphragm 36 takes place. The thickness of pad 44 is greater than the thickness of ring 38 so that pad 44 extends below ring 38 to engage the playing surface of tennis court It). Cavity 34 contains outlet 50 which is connected to one end of tubing 20. The other end of tubing 20 is connected to input 52 of indicator apparatus 22, as shown in FIG. I.  
  Indicator 22 may contain a plurality of inputs S2 suitable for connection to tubing 20. Each of the inputs S2 is connected in parallel through check valves 54 to pneumatic-clectric transducer or switch 56 shown dia grammatically in FIG. 4. Pneumatic-electric transducer 56 may be of the type made and sold by the Fairchild lndu trial Products Co. of(&#39;ommocls. Ne York under the desigtiation PSI&#34; HNlA. Pneumatic pressure of ()5 inch of \\ale|&#39; \\ill operate transducer 56. Variable orifice 58 connected to the input of transducer 56 opens to atmosphere as do check \alves 60.  
  The s\\ itch contacts 62 of pneumatic-electric transducer 56. operable by bellovv or diaphragm 63. are connected in series \vith battery 64 and an indicating means. .\s shown in Fl(i. 4. such indicating means may include a isual indicator. such as light 66. an audible indicator. such as born or buy/er 68. and a counter 70 for recording the cummulative number of impacts on the panel or panels 24 connected to indicator 22. Light 66. buy/er 68. and counter 70 are connected in parallel.  
  ln use. the tennis player hits the tennis balls tovvards impact sensing target 18. When a ball Sll&#39;ilsCS upper surface 26 of the target the impact force exerted on panel 24 causes pad 4-1- to deflect diaphragm 36 into cavity 34 generating a short pneumatic pulse in the cavity. The pneumatic pulse is transmitted through tube 20 to input 52 of pncumatic-electric transducer 56 via check valve 5-8 to connect battery 64 to the indicating means. causing operation of one or more of light 66. horn 68 and counter 7&#34;.  
  The air compression pulse produced by the sensing means 32 and transmitted via tubing 20 is trapped by checlv valve 54 \\ithitt a volume including bellovvs 63 and the tubing coupling pneumatic-electric transducer to checlv valves 54 and variable orifice S8. The resulting pressure. which is considerably less than the coinpression pulse amplitude. but many time greater than that required to actuate the transducer. is gradually reduced to the ambient pressure condition through \ariable orifice 58. This gradual reduction of the pressure condition corresponds to the prolonged indication which is vital to the effectiveness of the present invention as a teaching device Variable orifice 58 is adjusted so that the pulse produced pressure applied to pneumatic-eleetric transducer 56 is bled off at a rate cortimensuratc with the desired indicating time of the indicator 22. The longer the desired indicating time. the slower the bleed-off of the pressure.  
  When the pneumatic pressure resulting from the pulse-voluiiie interaction. described above. has been bled off to a sufficiently low level. pneumatic-electric transducer 56 disconnects the indicating means from battery 64 and impact sensing target 18 is ready to receive another impact. (heck valves 60 maintain ambient pressure in tubing 20 and sensing means 32.  
  While indicator 22 is shown as a separate element it will be appreciated that all or part of it may be incorporated into panel 24. if desired. For example. the entire indicating means may he made integral to panel 24. Or. the pncLunatic-electric transducer may he incorporated in panel 24 and connected to the indicator 22 by \vires. lf it is desired to eliminate a tangible connection between panel 24 and indicator 22. the pneumaticelectric transducer may operate a radio transmitter in panel 24 for supplying pulse signals to a suitable receivcr coupled to the indicating means.  
  Further. while a pneumatically operable device has been described above it will be appreciated that other means of sensing the impact of the objects may be employedv For example. an accelerometer or the electrical switch contacts 20 shown in FIG. 5 may be so employed. The prolonged signal generation necessary in the operation of the impact sensing target may he obtained by means such as a latching relay or monostable vibrator 82 interposed betneen the sensing means and an electrically operated indicator 84.  
 We claim:  
  I. A target positionable on a relatively unyielding surface for sensing the impact of objects comprising:  
 a stiff panel having means for locating said panel on the surface;  
 a sensor including a cavity in said panel having a diaphragm means mounted thereacross for sealing said ca\it v into a chamber and having means on said diaphragm means for engaging said surface: and  
 tubular transmitting means connected to said cham her and having means for maintaining the transmitting means and chamber at ambient pressure.  
 said diaphragm means being formed of a material possessing sufficient stiffness to pro\ ide a transient deflection from a quiescent position responsive to object impact forces sufficient to generate a transient pneumatic pulse for travel dovvn said transmitting means.  
  2. The target of claim I wherein said surface com prises a tennis court and the area of said panel is a predetermined fraction of the tennis court area.  
  3. The target of claim I wherein said diaphragm means is formed of a material sufficiently stiff to support a proportionate share of the weight of said panel yet sufficiently flexible to transiently dellect on object impact.  
  4. The target of claim 3 wherein said diaphragm means includes means for limiting the deflection ofsaid diaphragm to avoid damage thereto.  
  5. The target ofelaim 4 wherein said deflection limiting means includes means mounted on said diaphragm means and abuttable with the interior of said cavity.  
  6. The target of claim I further including a pneumatic pressure operated transducer having a fixed volume and including unidirectional flovv control means interposed between said transmitting means and said transducer for isolating said fixed volume and for permitting entry ofthe pneumatic pulse created by said diaphragm means into said volume to establish a pressure therein sufficient to operate said transducer.  
  7. The target of claim 6 including indicator means coupled to said transducer for providing a perceptible indication of object impact.  
  8. The target ofelaim 7 wherein said indicator means includes a visually perceptible indicator.  
  9. The target ofelaim 7 wherein said indicator means includes an audibly perceptible indicator.  
  10. The target of claim 7 wherein said indicator means includes a counter.  
  I l. The target ofelaim 7 wherein said target includes said transducer located in said panel and includes further transmitting means coupled to said transducer for transmitting a signal corresponding to said pneumatic pulse to said indicator means.  
  12. The target ofelaim ll wherein said further transmitting means comprises wires.  
  [3. The target ofelaim l I wherein said further transmitting means comprises a radio transmitter and receiver.  
  [4. The target of claim 6 wherein said transducer includes bleed means coupled to said volume for reduc-