Patent Publication Number: US-2020284558-A1

Title: Hit-scoring apparatus and target panel for shooting practice

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application is a Continuing application of U.S. application Ser. No. 16/068,100, filed Jul. 3, 2018, which is a U.S. National Phase filing of co-pending, commonly owned PCT Application No. PCT/US17/013026, filed Jan. 11, 2017, which claims priority from Israeli Patent Application No. 243602, filed Jan. 13, 2016 all which are incorporated herein by reference in their entirety 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a hit-scoring apparatus for shooting practice. It also relates to a hit-scoring target panel for shooting practice. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 6,994,347 discloses a hit-scoring apparatus for shooting practice, comprising a target holder consisting of a body constituting the fixed first jaw and a moveable second jaw of a clamping device, the first jaw and the second jaw being electrically insulated from one another, and means adapted to produce a relative movement between the first jaw and the second jaw. A target panel is clamped between the first and second jaws and consists of a plurality of layers including an electrically conductive first layer and an electrically conductive second layer separated and spaced apart from the front layer by at least one electrically non-conductive layer. When the target panel is clamped between the first and second jaws of the target holder, separate electrical contacts are established between the first layer and the first jaw on the one hand, and between the second layer and the second jaw on the other hand, the first and second jaws being further connectable to a hit-scoring unit. 
     In order that the second layer makes electrical contact with the electrically conductive rear jaw, the metallic surface of the second layer must initially extend below the lower edge of the target and be folded at its lower edge during manufacture and secured by adhesive to the rear surface of the target. This can only be done manually and is therefore time-consuming and expensive. 
     The first layer is subdivided into different areas that are electrically insulated from each other and are each connected to a different one of the electrical contacts on the first jaw. The second layer provides a unitary conductive surface that is connected to the second jaw, which must be electrically conductive. An electronic circuit is mounted inside the fixed first jaw and detects when the two layers are shorted by a bullet. To this end, the electronic circuit must also be electrically connected to the conductive second jaw, this being done by a wire. Constant movement of the second jaw may subject the wire to fatigue, causing it to be break eventually and require replacement. 
     The different areas of the first layer allow the electronic circuit to discriminate between distinct areas of the target and provide feedback to the marksman as to where the bullet entered the target. The value of this feedback clearly depends on the number of distinct areas that can be separately isolated in the first layer. In theory, the second layer could also be subdivided into distinctive areas in order to improve the resolution of the discrimination but in practice this would require that the second jaw support separate contacts, each of which would then need to be connected to the electronic circuit by a respective wire. 
     In the target panel disclosed in U.S. Pat. No. 6,994,347, a discrete conductive area of the target connected to a contact pad in the apparatus that senses the short circuit caused by the bullet defines uniquely where the bullet strikes the target. This requires that the contact areas be spatially separated: the conductive tracks that route the contact areas to the contact pads cannot be allowed to cross a different contact area. This limits the measurement resolution of such a target since any given contact area cannot easily be further sub-divided into concentric areas owing to the difficulty in routing each sub-area to a separate contact pad. Provided that were sufficient contact pads available, it would be possible to sub-divide the contact areas and connect them by wires to the contact pads. However, this is not really practical since it significantly increases the cost of assembly. 
     It must be borne in mind that target practice is often carried out in hostile environments and the device must be sufficiently robust to withstand manhandling. The use of wires to connect the contacts of the moveable jaw to the second conductive layer of the target militates against the provision of additional channels that would allow better discrimination. 
     It would clearly be preferable to allow the second layer also to be subdivided in order to increase the resolution of the electronic circuit, while doing so in a manner that obviate the needs for wire connections from the moveable jaw to the discrimination circuitry. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide an improved hit-scoring apparatus for shooting practice that addresses these requirements. 
     This object is realized by a hit-scoring apparatus for shooting practice and a target panel therefor having the features of the respective independent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a cross-section of a target panel according to the invention; 
         FIG. 2  is a perspective view showing a detail of electrically conductive layers in the target panel; 
         FIG. 2 a    is identical to  FIG. 2  but shows the contact areas in complementary colors for greater clarity; 
         FIG. 3  is a perspective view of the two layers of the target panel showing the principle of discrimination between different bullet paths; 
         FIG. 4  is a perspective view of the two layers of the target panel relating to a truth table that maps pairs of indication signals to different areas of the target panel; 
         FIGS. 5 to 8  are pictorial representations of part of a hit-scoring apparatus for use with the target panel; and 
         FIG. 9  shows schematically a detail of a circuit for counting hits and determining possible areas where the target panel is hit. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       FIG. 1  is a pictorial cross-section of a target panel  10  according to the invention having an electrically conductive first layer  11  and an electrically conductive second layer  12  separated and spaced apart from the first layer by at least one electrically non-conductive layer  13  formed of standard, double-layer, corrugated cardboard. The first layer  11  is directed forward toward the sniper and comprises a thin aluminum film, advantageously provided with an anodized or otherwise colored front surface of a dark hue which reduces reflectivity and glare without impairing conductivity. The second layer  12  is likewise a thin aluminum film, which is glued to the rear surface of the non-conductive layer  13 . The outer rear surface of the panel is constituted by a layer of resin-impregnated paper  14  for reinforcement and waterproofing. 
     A projectile such a bullet  15  having a metal shell penetrating the target panel shorts the two conductive layers  11 ,  12 , thereby completing an electrical circuit, which indicates a hit and also provides an indication of where the target was hit. To this end, the layers are sub-divided into distinct target areas that correspond to respective areas of anatomy of the target such as the head, upper torso, heart area etc. The target areas are electrically insulated from each other and each is connected to a respective conductive pad at a lower edge of the target panel, so that when the target panel is clamped between jaws of a hit-scoring apparatus, the conductive pad makes good electrical contact with a contact disposed on a jaw in the hit-scoring apparatus. 
       FIGS. 2 and 2   a  are perspective views showing a detail of the layers  11  and  12  of the target panel  10 .  FIG. 2 a    is the same as  FIG. 2  except that the contact areas are shown using different colors for greater clarity for those jurisdictions where it is possible to file colored drawings. In jurisdictions where colored drawings are inadmissible,  FIG. 2 a    will be converted to greyscale. The first layer  11  has a central circular conductive first area  20  to which there are connected conductive tracks  20   a  and  20   b  that are routed to a contact pad  20   c . Surrounding the first area  20  is an annular conductive second area  21 , which is electrically insulated from the first area  20  and to which there are connected conductive tracks  21   a  and  21   b  that are routed to a contact pad  21   c . Likewise, surrounding the second area  21  is an annular conductive third area  22 , which is electrically insulated from the second area  21  and to which there are connected conductive tracks  22   a  and  22   b  that are routed to a contact pad  22   c . The contact pads  20   c ,  21   c  and  22   c  are located toward the lower edge of the layer  11  for abutting respective contacts of the hit scoring apparatus as described below with reference to  FIGS. 5 to 8  of the drawings. 
     Thus far, the target panel  10  is functionally identical to that described in above-mentioned U.S. Pat. No. 6,994,347. However, unlike U.S. Pat. No. 6,994,347 where the rear target panel has only a single conductive area that is folded back in order to allow connection to the rear jaw, in the target panel  10  according to the invention the second layer  12  has multiple conductive areas denoted by  20 ′,  21 ′ and  22 ′. Thus, a central circular conductive first area  20 ′ is routed via conductive tracks  21   a ′ and  21   b ′ to a contact pad  20   c ′. Surrounding the first area  20 ′ is an annular conductive second area  21 ′, which is electrically insulated from the first area  20 ′ and to which there are connected conductive tracks  21   a ′ and  21   b ′ that are routed to a contact pad  21   c ′. Likewise, surrounding the second area  21 ′ is an annular conductive third area  22 ′, which is electrically insulated from the second area  21 ′ and to which there is connected a conductive track  22   a ′ that is routed to a contact pad  22   c ′. The contact pads  20   c ′,  21   c ′ and  22   c ′ are also located toward the lower edge of the layer  12  for abutting respective contacts of the hit scoring apparatus. 
     The first area  20 ′ is also routed via a conductive track  20   d ′ to a conductive area  20   e ′ in a portion of the second layer  12  that is spatially displaced from the central portion  21 ′. Similarly, the second area  21 ′ is also routed via a conductive track  21   d ′ to a conductive area  21   e ′ proximate and partly surrounding the area  20   e ′ and the third area  22 ′ is also routed via a conductive track  22   d ′ to a conductive area  22   e ′ proximate and partly surrounding the area  21   e ′. In order to allow detection of a bullet penetrating one of the areas  20   e ′,  21   e ′ and  22   e ′ in the second layer  12 , complementary conductive areas  20   e ,  21   e  and  22   e  are provided in overlapping areas of the first layer  11  and are routed to respective contact pads  20   c ″,  21   c ″ and  22   c ″ located toward the lower edge of the layer  12  for abutting respective contacts of the hit scoring apparatus. The contact areas  20   e ,  21   e  and  22   e  on the first layer  11  together with the complementary contacts  20   e ′,  21   e ′ and  22   e ′ of the second layer  12  define a generally rectangular portion of the target corresponding to critical anatomical features of the target, which when hit by a bullet are likely to cause significant damage to the victim. The same is true regarding the contact areas  20 ,  21 ,  22  of the first layer  11  corresponding to and overlapping the contact areas  20 ′,  21 ′,  22 ′ of the second layer  12 . In order to ensure during manufacture that the complementary contacts of both layers  11  and  12  are in proper mutual overlapping relationship, apertures  25   a ,  25   b  and mutually aligned apertures  25   a ′,  25   b ′ shown in  FIG. 3  are formed in the first and second layers  11  and  12  respectively, so that when the respective apertures  25   a ,  25   a ′ and  25   b ,  25   b ′ are aligned, the two layers  11  and  12  are properly registered. 
     As will be explained with reference to  FIG. 5 , all the contact pads of both layers  11  and  12  make abutting contact with complementary contacts of the hit scoring apparatus, of all of which are mounted on the same fixed jaw thereof. To this end, one or more apertures or gaps  26  are formed in the lower edge of the first layer  11  in overlapping relationship with the contact pads  20   c ′,  21   c ′ and  22   c ′ on the second layer  12 . By such means the contact pads  20   c ′,  21   c ′ and  22   c ′ are generally aligned with the contact pads  20   c ,  21   c ,  22   c ,  20   c ″,  21   c ″ and  22   c ″ on the first layer  11  and all face in the same in the same direction. In the embodiment shown in  FIG. 2 , the contact pads  20   c ′,  21   c ′ and  22   c ′ on the second layer  12  are clustered together, thereby allowing accessibility to the contacts of the hit scoring apparatus through the single aperture  26  in the first layer  11 . However, this is not a requirement and if desired the contact pads on the two layers may be staggered thereby requiring that multiple apertures or gaps be formed in the first layer to provide accessibility to the contact pads of the second layer. 
     It is clear that a bullet entering the center of the first area  20  of the first layer  11  and exiting the first area  20 ′ of the second layer will short the contact pads  20   c  and  20 ′ thereby providing a direct indication of where the target was hit. However, owing to the mutually overlapping tracks of the first and second layers that are used to route the annular contact areas  21 ,  22  and  21 ′,  22 ′ this is no longer always the case when a bullet enters any but the centermost contact areas  20  and  20 ′. Thus, with reference to  FIG. 3 , consider a bullet that enters the first layer  11  of the target panel at arrow A and exits the second layer  12  at arrow A′. It is clear that the bullet strikes in the region of the first annular area  21 , but it penetrates the conductive track  20   a  in the first layer  11  that routes the central target area  20  to the contact pad  20   c . In the arrangement of U.S. Pat. No. 6,994,347 where the second layer  12  is a unitary conductive film, only the contact pads in the front layer allow for discrimination of where the bullet strikes the target. Thus, if the target panel  10  were employed in such an arrangement, a bullet intersecting a first contact area through the conductive track that routes a second, different contact area to the contact pad would be registered as having hit the second contact area. In other words, the contact area connected to the contact pad that senses the short circuit caused by the bullet defines uniquely where the bullet strikes the target. This requires that the contact areas on the first layer of the target panel in U.S. Pat. No. 6,994,347 be spatially separated: the conductive tracks that route the contact areas to the contact pads cannot be allowed to cross a different contact area. This limits the measurement resolution of such a target. 
     This problem is avoided in the target panel  10  according to the invention since the bullet penetrates two discrete layers and therefore produces two signals, each indicative of which area it strikes in each layer. Thus in the above example, the apparent ambiguity of where the bullet penetrates the first layer  11  is resolved by the fact that it penetrates the second layer  12  in the annular contact area  21 ′ surround the central area  20 . This being the case, the bullet cannot have entered the first layer in the central area  20  even though it is the contact pad  20   c  connected to the central area  20  in the first layer  11  that senses the short circuit. 
     Likewise, we can consider a bullet that enters the first layer  11  of the target panel at arrow B and exits the second layer  12  at arrow B′. It is clear that this bullet also strikes in the region of the first annular area  21 , but it penetrates the conductive track  20   a ′ in the second layer  12  that routes the central target area  20 ′ to the contact pad  20   c ′. In this case the apparent ambiguity in the second layer  12  is resolved by the first layer  11 , which unambiguously indicates the bullet entered the first annual area  21 . 
     Extending this principle,  FIG. 4  is a perspective view of the two layers  11  and  12  of the target panel wherein different areas of the target are identified using a matrix, allowing identification of where a bullet strikes the target according to which contacts of the two layers are shorted by the bullet. This is summarized in the following truth table. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Truth Table 
               
            
           
           
               
               
               
               
            
               
                 Contact Pad ID 
                 20c′ (Dark Grey) 
                 21c′ (Blue) 
                 22c′ (Black) 
               
               
                   
               
               
                 20c (Brown) 
                 Aa 
                 Ab 
                 Ac 
               
               
                 21c (Purple) 
                 Ba 
                 Ab′, Ba, B′a 
                 x 
               
               
                 22c (Orange) 
                 Ca 
                 x 
                 Ac′, ac′, ac, B′b, 
               
               
                   
                   
                   
                 Bb, Cb, Cb 
               
               
                 20c″ (Grey) 
                 Cd 
                   
                   
               
               
                 21c″ (Brown) 
                 Cd 
                   
                   
               
               
                 22c″ (Green) 
                 Cd 
               
               
                   
               
            
           
         
       
     
     It should be noted that the above Truth Table is only partial and representative. Better discrimination can be achieved by sub-dividing the target layers further, the only practical limitation being the need to route each thus designated target area to a separate contact pad. This in turn is limited only by the width of the target panel and the jaw in the hit scoring apparatus. It should also be noted that in order to sub-divide areas even further, it may be desirable or necessary to provide additional layers having conductive areas that are routed to corresponding contact pads. However, in the interest of brevity this is not shown in the figures since the principle of operation is unchanged. 
     So far we have described only the target panel  10 , it being understood that it operates in conjunction with a custom hit scoring apparatus that will now be described. However, before doing so, we summarize the distinctive features of the target panel per se as comprising a pair of spaced part electrically conductive first and second layers separated by at least one electrically non-conductive layer. Each conductive layer has at least two discrete conductive areas routed by respective conductive tracks to separate contact pads on a common edge of the target panel. At least one of the conductive tracks in each layer intersects a conductive area in the same layer that is routed by a different conductive track to a different contact pad in the same layer. The conductive tracks in each of the conductive layers are arranged such that a portion of a conductive track that intersects a contact area in the first layer does not overlap a portion of a conductive track that intersects a contact area in the second layer. For example the conductive track identified as  20   a  in  FIG. 2  and colored purple in  FIG. 2 a   , crosses through the discrete areas identified as  21  and  22  in  FIG. 2  and colored purple and orange, respectively in  FIG. 2 a   . However, the conductive track  20   a  in the first layer  11  cannot overlap or intersect any other conductive track in either of the two layers and specifically not in the second layer  12 . This ensures that a possible ambiguity as to which contact area is penetrated by a bullet that pierces a conductive track in one layer is resolved by the certainty as to which contact area is penetrated by the bullet in the other layer. 
     In saying this, some clarification is required regarding the definition of the contact areas. For example, Table 1 above may suggest that a bullet that shorts contact pads  21   c  and  21   c ′ is identified by one of three different areas identified as Ab′, Ba and B′a. However, this is merely a question of definition since all these areas are within the first annular area in each layer; so we can say with certainty that the bullet hit the target somewhere within the overlapping annular areas shown purple and blue in  FIG. 2 a   . We also know with certainty that the bullet did not penetrate the conductive track  20   a ′ in the second layer  12  (since this would have been detected by a different contact pad), thus effectively limiting the right quadrant of the annular overlap. The same of course is true of the outermost annular areas shown orange and black, respectively, in  FIG. 2 a   . If further discrimination within these areas is required, this could be done by sub-dividing the areas into mutually separated areas each routed to a discrete contact pad. This might also require use of an auxiliary conductive layer as noted above. 
     Reference is now made to  FIGS. 5 to 8  showing perspective views of a clamping device  30  of a hit-scoring apparatus according to the invention comprising a fixed jaw  31  supporting on a rear surface  32  thereof a plurality of first contacts  33  and second contacts  34 . The clamping device  30  further includes a movable jaw  35  that is mounted on a pin  36  projecting from the rear surface  32  of the fixed jaw  31  and is biased into an open position as shown in  FIG. 5  by a coil spring  37 . The movable jaw  35  is operated by a handle  38  in manner known per se. The fixed jaw  31  is attached to a mounting plate  39  by means of which the clamping device  30  may be supported on a suitable support surface. The mounting plate  39  also prevents rotation of the movable jaw  35  about the pin  36 , thereby ensuring that the two jaws mate properly when closed. Proper registration between the two jaws is ensured by means of lugs  40 ,  40 ′ projecting on opposite sides of the fixed jaw  31  which engage complementary apertures  41 ,  41 ′ in the movable jaw  35 . The pairs of lugs and apertures { 40 ,  41 } and { 40 ′,  41 ′} are spatially aligned with the respective apertures { 25   a ,  25   a ′} and { 25   b ,  25   b ′} of the target panel  30  so that when the target panel  30  is clamped between the two jaws  31  and  35 , the contact pads in the target panel make good electrical contact with the respective contacts  33 ,  34  on the fixed jaw  31 . 
     Each of the jaws  31  and  35  may consist of three sections: a central section and two lateral sections inclined with respect to the central section at an obtuse angle of about 160°. This requires that the target panel be foldable about vertical creases or that the act of closing the jaws of the clamping device  30  induce the required folding, which increases the rigidity of the target panel. This is important because if steps are not taken to support the rear second layer  12  of the target panel  10 , a bullet that penetrates the front first layer  11  may simply push the rear second layer  12  away from the first layer  11 , without actually penetrating it. Were this to occur, the bullet would not create the required short-circuit between the two layers by means of which penetration is detected. Nevertheless, it will be appreciated that the required support of the rear second layer  12  may be achieved by other means, such as by mounting a rigid layer behind the second layer  12  or clamping a rigid or semi-rigid panel behind the target panel  10 . 
     The fixed jaw  31  has a generally hollow housing containing one or more circuit boards  45  (shown in  FIG. 7 ) to which proximate contacts  33  or  34  are connected and which contain circuitry for sensing a short-circuit between one of the first contacts  33  and one of the second contacts  34  and producing indication signals indicating which of the first and second contacts were shorted. The circuit boards  45  may also contain a processor that is responsive to the indication signals for identifying which area of the target panel was hit. Additionally or alternatively, the circuit boards  45  may be connected to an outlet  46 , allowing connection to a remote processor and/or indicator using either a wired or wireless protocol. They may also be connected to a jack socket  47  for connecting an external DC supply. 
     Significantly, no contacts are provided on the movable jaw  35 , which may be formed of an electrically insulating material. This has the benefit that the only connections from the contacts  33  and  34  to the circuit boards  45  are within the fixed jaw  31  and are thus not subjected to movement or strain when opening and closing the clamping device  30 . 
     Reference is now made to  FIG. 9  showing schematically a detail of a circuit for counting hits and determining possible areas where the target panel is hit. Before describing this circuit, it should be noted that providing multiple contact areas on both layers  11  and  12  complicates the detection as compared with the arrangement disclosed in U.S. Pat. No. 6,994,347 where the rear second layer constituted a unitary contact that could therefore serve as a ground plane. In such an arrangement, each contact pad cooperates with the ground plane to act as switch, whose closure indicates which contact area was penetrated by the bullet. 
     But this is not the case in the present invention, because we need to determine which contact area in each layer is hit by the bullet, and therefore the contacts in neither layer can serve as a unitary ground plane. To this end, the circuit comprises for each pair of contact pads in the two layers e.g. { 20   c ,  20   c ′}, { 20   c ,  21   c ′} and so on a discriminator comprising a first timer  50  having an input connected to the corresponding contact pad e.g.  20   c  in the first layer and a second timer  51  having an input connected to the corresponding contact pad e.g.  20   c ′,  21   c ′ in the second layer. The timers  50 ,  51  may be constituted by an IC circuit in the ubiquitous  555  or  556  families The auxiliary components are not shown in  FIG. 9  for ease of description and because use of these ICs is known per se. The circuit is powered by a DC power supply  52  that may be a battery inside the fixed jaw or may be derived from an external power supply coupled to the circuit via the DC jack socket  47 . A normally open electronic switch  53  is connected between each contact pad  20   c ′,  21   c ′,  22   c ′ of the second layer  12  and GND. In the figure the switch  53  is shown as a NPN bipolar junction transistor although other devices such as opto-couplers may equally well and even preferably employed. Thus, with reference to the figure, the base of the transistor is connected to the respective contact, the emitter is connected to GND and the collector is connected to the input (Trigger) of the second timer  51 . 
     When a bullet  15  shorts between the two conductive layers  11 ,  12  of the target panel  10  as shown by the chain dotted lines for each channel, DC voltage is supplied simultaneously to the first timer  50  and to the base of the transistor  53 , which is thus biased into conduction. Again, for ease of description, the biasing components are not shown in the figure. The first timer  50  produces a pulse constituting a first indication signal, which identifies the contact pad in the first layer shorted by the bullet. The second timer  51  produces a pulse of shorter duration constituting a second indication signal, which identifies the contact pad in the second layer shorted by the bullet. The outputs of all the timers  50 ,  51  are fed to a processor via a multiplexer neither of which is shown. The bullet passes through the target panel so fast that the duration of the short circuit is substantially instantaneous. The timers  50 ,  51  are therefore configured to produce pulses of much longer duration in order to allow the processor sufficient time to scan all of the timers and determine which pair of timers is active. This in turn allows the processor to access a read-only memory in which the Truth Table is stored and thereby determine which contact areas are shorted by the bullet. The processor may, of course, be a programmable device that is programmed to compute a cumulative count of hits and to show for each one where the target was hit. The processor, its associate memory and other circuitry may be mounted on the circuit board  45  shown in  FIG. 7  or it may be coupled thereto via the outlet  46 . 
     For the sake of completeness, it will also be appreciated that the results of the processor may be output in various ways. For example, they can be shown graphically on a display device coupled to the processor. Alternatively, a dummy target can be coupled to the processor and can have in discrete areas of the target different colored LEDs that are arranged to illuminate and provide a visual record. The cumulative hit count can be displayed on the display device or on a separate dedicated counter.