Abstract:
An arrow is provided with a light emitting function, a nock with a light emitting function, and a light emission control device to be used in an arrow which thereby realize accurate and stable light emission periods of time and a reduction in size and weight of light emitting members by using an electronic circuit with an acceleration sensor switch in its light emission control part. The control device includes an acceleration switch, a capacitor circuit including a capacitor and a resistor, and an electrical circuit installed inside the arrow, nock, or attachable to and detachable from the arrow. Electricity is applied when the arrow is discharged from a bow to emit light for a set period of time.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The present invention relates to an arrow and nock with a light emitting function. More specifically, the present invention relates to an arrow with a light emitting function, a nock with a light emitting function, and a light emission control device to be used in the arrow, which make it possible for a shooter to confirm whether an arrow discharged by the shooter hit the target or not.  
         [0003]     2. Background Art  
         [0004]     As sports and games for discharging arrows toward targets, there is kyudo, archery, bowgun (crossbow), darts, etc.  
         [0005]     For example, kyudo is normally divided into near-target events with a shooting distance of 28 m and distant-target events with a shooting distance of 60 m, and in both events, a circular target is shot by an arrow.  
         [0006]     In archery, mainly, an 18 m shooting distance is set for indoor games, and for outdoor games, 30 m, 50 m, and 90 m shooting distances are set. Dart games are made competitive by scoring points by throwing darts directly by hand without using a bow, and recently, dart enthusiasts have been increasing in Japan as well.  
         [0007]     It is visually checked by a shooter him/herself during training or by a judge during matches whether an arrow of these has hit the target or not.  
         [0008]     However, in outdoor playing fields, it becomes difficult to visually check the striking point of the arrow when the sun goes down and twilight occurs, and it takes time to determine the next shooting direction of an arrow, and this causes loss of the rhythm and makes it difficult for a shooter to concentrate on training.  
         [0009]     An invention shown in  FIG. 7  has been proposed for solving this problem. According to this invention, the arrow  101  has a light emitting device  103  for illuminating the nock main body  102  when it hits the target or ground, etc. Inside the light emitting device  103 , a battery  104  is fixed, and to the negative electrode terminal  105  of the battery  104 , a lead wire as a negative electrode conductor extending from the light emitting diode  106  is connected. On the other hand, to the front end of a lead wire as a positive electrode conductor from the light emitting diode  106  and to the front end of a lead wire as a positive electrode conductor to be connected to the positive electrode terminal of the battery  104 , switch opening and closing pieces  108  that form a switching device provided in a second space  107  are connected. The switch opening and closing pieces  108  are fixed at their base portions while being in contact with each other, and a switch operator  109  that opens and closes the switch opening and closing pieces  108  is provided so as to advance and retreat inside the second space  107  and the first space  110 . The front end of the operating part  112  of this switch operator  109  enters between the switch opening and closing pieces  108  before discharging an arrow by an urging force of a coil spring  111  provided inside the first space  110 , and the electric conduction path is shut off.  
         [0010]     In addition, at the front end of the light emitting device  103 , an air exhaust hole  113  is provided for mainly exhausting air in the first space  110  to the outside of the light emitting device  103 . In this air exhaust hole  113 , a check valve is provided to prevent air flow from the outside although allowing the air in the first space  110  to be exhausted.  
         [0011]     Furthermore, an air introducing hole  114  with a diameter smaller than the diameter of the air exhaust hole  113  is provided around the air exhaust hole  113 . In the light emitting device thus constructed, when an arrow is discharged and hits the target or ground, etc., the switch operator  109  moves toward the arrow front end by inertia against the urging force of the coil spring  111 , whereby the air inside the first space  111  becomes high in pressure and is exhausted from the air exhaust hole  113 , the operating part  112  is separated from the switch opening and closing pieces  108 , and the light emitting diode  106  emits light. Then, when the switch operator  109  is about to be pushed back by the urging force of the coil spring  111 , in the air exhaust hole  113 , air flow into the first space  110  is prevented by the check valve so as to gain as much time as possible until air flows-in only from the air introducing hole  114 , the switch opening and closing pieces  108  return to the original positions, and the electric conduction path is shut off, and during this period of time, the light emitting diode  106  is made to emit light. See Japanese Unexamined Patent Publication No. 2003-35500.  
       SUMMARY OF THE INVENTION  
       [0012]     According to the invention, even in a case where the sun goes down and twilight occurs or a shooter has reduced visual acuity, it becomes possible for the shooter to confirm the position an arrow arrives since the nock is illuminated by a light emitting means when the shooter discharges an arrow and the arrow hits a target or the ground, etc.  
         [0013]     However, the light emitting means of the nock conducts electricity by separating the operating part  112  from the switch opening and closing pieces  108  by inertia of the switch operator  109  itself when the arrow  101  hits and stops, and makes the light emitting diode  106  emit light, so that the parts are worn out according to the number of times of use of the arrow and this changes the period of light emission and causes the switch part to be broken, and therefore there is a problem that stable accuracy cannot be maintained.  
         [0014]     In addition, the light emitting means emits light when the arrow discharged by a shooter hits a target or the ground, etc., so that the locus of the arrow until it hits the target cannot be confirmed, and when several shooters shoot, it cannot be confirmed where the arrows came from by light emission after the arrows hit the target.  
         [0015]     The present invention was made in view of the above-described circumstances, and an object thereof is to provide an arrow with a light emitting function, a nock with a light emitting function, and a light emission control device to be used for an arrow, which realizes stable and accurate light emission periods and reduction in size and weight of the light emitting members by using an electronic circuit using an acceleration sensor switch in the light emission control part.  
         [0016]     In order to achieve the object, an arrow with a light emitting function of the invention has a light emission control part that emits light when the arrow is discharged, wherein the light emission control part includes an electrical circuit in which an acceleration sensor switch that starts by the arrow acceleration, a light source provided at a position of the arrow visible to a shooter, and a battery for supplying a current to the light source when the acceleration sensor switch starts, and a capacitor circuit to be supplied with a current for a predetermined period after the acceleration sensor switch is turned off are installed.  
         [0017]     Herein, the light emission control part to be installed in the arrow includes an electronic circuit having a light emitting diode serving as a light source, a battery, an acceleration sensor switch, and a capacitor circuit. This acceleration sensor switch is turned on by an acceleration (approximately 200 G) applied when the arrow is discharged from the bow, and causes the light emitting diode to emit light while the capacitor circuit  15  is charged.  
         [0018]     Even when the arrow leaves the bow and turns into constant-speed flight and the acceleration sensor switch is turned off, light is emitted for a predetermined period of time by discharging a current charged in the capacitor circuit, whereby it becomes possible to confirm where the arrow hits.  
         [0019]     In addition, to achieve the above-mentioned object, a nock with a light emitting function relating to the invention is a nock provided in an arrow, having a light emission control part that emits light when the arrow is discharged, wherein the light emission control part has an electrical circuit in which an acceleration sensor switch that starts by an acceleration of the arrow, a light source provided in the nock, a battery for supplying a current to the light source when the acceleration sensor switch starts, and a capacitor circuit to which a current is supplied for a predetermined period of time after the acceleration sensor switch is turned off are installed.  
         [0020]     Herein, the light emission control part to be installed in the nock attached to the rear end of the arrow main body includes an electronic circuit formed of a light emitting diode serving as a light source, a battery, an acceleration sensor switch, and a capacitor circuit.  
         [0021]     Therefore, the acceleration sensor switch is turned on by an acceleration when the arrow is discharged, the light source of the light emitting diode emits light, and the capacitor circuit is charged. Then, when the arrow leaves the bow and the acceleration sensor switch is turned off, a current is discharged from the capacitor circuit to make the light emitting diode emit light for a predetermined period of time.  
         [0022]     In addition, to achieve the above-mentioned object, a light emission control device to be used for the arrow of the invention is a light emission control device to be attached to the arrow, and the light emission control device has an electrical circuit including an acceleration sensor switch that starts by an acceleration of the arrow, a light source that emits light when the arrow is discharged, a battery for supplying a current to the light source by the start of the acceleration sensor switch, and a capacitor circuit that is supplied with a current for a predetermined period of time after the acceleration sensor switch is turned off.  
         [0023]     Herein, the light emission control device that is attachable to an arrow main body when the arrow is discharged is formed of an electronic circuit in which a light emitting diode serving as a light source, a battery, an acceleration sensor switch, and a capacitor circuit are installed.  
         [0024]     Then, by an acceleration applied when the arrow is discharged from the bow, the acceleration sensor switch is turned on, the light emitting diode emits light, and the capacitor circuit is charged, and even when the arrow leaves the bow and the acceleration becomes zero and the acceleration switch is turned off, due to discharge from the capacitor circuit, the light emitting diode emits light for a predetermined period, whereby the locus of the arrow becomes visible even in the dark and it becomes possible to confirm where the arrow hits.  
       EFFECTS OF THE INVENTION  
       [0025]     According to the arrow, the nock and the light emission control device of the invention described above, the electrical circuit is energized by an acceleration applied when a shooter discharges an arrow and the LED element emits light, and even after the arrow hits a target or the ground, etc., light is emitted for several seconds due to discharge from the capacitor, whereby it becomes possible to easily confirm the locus of the arrow and the position the arrow hit even in a dark playing field or a training field.  
         [0026]     In addition, the electrical switch is not operated by mechanical operations, but is operated by using the acceleration applied to the arrow, so that erroneous operations and functional deterioration due to wearing according to the frequency of use are eliminated.  
         [0027]     Furthermore, the electronic circuit includes an LED element, a transistor, and a capacitor, and is energized only while an acceleration is applied to the arrow, so that power consumption is very small and very economical. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]      FIG. 1  is a side explanatory view showing an example of an arrow with a light emitting function to which the invention is applied;  
         [0029]      FIG. 2  is a sectional explanatory view showing the internal mechanism of  FIG. 1 ;  
         [0030]      FIG. 3  is an electrical circuit diagram of  FIG. 2 ;  
         [0031]      FIG. 4  is a sectional explanatory view showing an example of a nock with a light emitting function to which the invention is applied;  
         [0032]      FIG. 5  is a perspective view showing an example of a light emission control device with a light emitting function to which the invention is applied;  
         [0033]      FIG. 6  is an enlarged explanatory view showing the internal mechanism of  FIG. 5 ; and  
         [0034]      FIG. 7  is a sectional explanatory view showing an example of a nock with a conventional light emitting function. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0035]     Hereinafter, an embodiment of the invention is described with reference to the accompanying drawings for understanding of the invention.  
         [0036]      FIG. 1  is a side explanatory view showing an example of an arrow with a light emitting function to which the invention is applied,  FIG. 2  is an explanatory view showing the internal mechanism of  FIG. 1 , and  FIG. 3  shows an electrical circuit of  FIG. 2 .  
         [0037]     The arrow  1  shown herein includes a nock  3  attached to the rear end of an arrow shaft  2 , an arrowhead  4 , and fletchings  5 .  
         [0038]     Inside the arrow shaft  2 , a light emission control part  7  is installed, and this light emission control part  7  includes an electrical circuit that has an acceleration switch  8 , a capacitor circuit  11  composed of a capacitor  9  and a resistor  10 , a lithium battery  12 , a transistor  13 , and an LED element  14 .  
         [0039]     Herein, the lithium battery  12  is disposed at the front end side inside the arrow shaft  2 , and an acceleration switch  8  is provided at the rear portion of this lithium battery  12 . This acceleration switch  8  has two thin metal plates  15 A and  15 B which are fixed at their rear ends and their front ends are separated from each other toward the arrow advancing direction. The metal plate  15 A of the acceleration switch  8  is connected to the cathode side of the lithium battery  12  and the metal plate  1   5 B is connected to the anode side of the lithium battery  12  via the capacitor circuit  11 .  
         [0040]     In addition, one terminal of the LED element  14  is connected to the anode side of the lithium battery  12  via a collector terminal of the transistor, and the other terminal of the LED element  14  is connected to the cathode side of the lithium battery. The base terminal of the transistor  13  is connected to the resistor  10  of the capacitor circuit  11 , and the emitter terminal of the transistor  13  is connected to the anode side of the lithium battery  12 .  
         [0041]     Furthermore, the LED element  14  is fitted inside a transparent nock  3  provided at the rear end of the arrow shaft  2 .  
         [0042]     When the arrow is accelerated by the bow, the two thin metal plates  15 A and  15 B of the acceleration switch  8  bend inward due to inertia, and the metal plates  15 A and  15 B come into contact with each other, temporarily conduct electricity, and charge the capacitor  9  while making the LED element  14  emit light. Furthermore, when the arrow leaves the bow and the acceleration ends, the metal plates  15 A and  15 B restore due to their elasticity and cut electric conduction.  
         [0043]     Next, electricity charged in the capacitor  9  flows into the base terminal of the transistor  13  through the resistor  10 . During electric conduction to the base terminal of this transistor  13 , the collector terminal and the emitter terminal of the transistor  13  conduct electricity, and the electricity flows from the cathode side of the lithium battery  12  to the LED element  14  side and makes the LED element  14  emit light, and passes through the transistor  13  and flows into the anode side of the lithium battery  12 .  
         [0044]     The period of electric conduction between the collector and the emitter of the transistor  13  as a period of light emission of the LED element  14  is determined by the period of electricity conduction to the base, and can be set by summing the capacitance of the capacitor  9  and the resistance value of the resistor  10 .  
         [0045]     The lithium battery does not always need to be installed in the front end side of the arrow shaft, however, by installing the lithium battery that is heaviest in the light emission control part in the front end side of the arrow shaft, its weight is well balanced with the LED element, transistor, and capacitor installed in the rear portion of the arrow shaft, whereby normal balance of the arrow can be maintained.  
         [0046]     Next,  FIG. 4  is a sectional explanatory view showing an example of a nock with a light emitting function to which the invention is applied.  
         [0047]     The nock  3  has a nock main body  16  in which a notch  15  for hooking a bowstring is formed, and a light emission control part  7  that makes an LED  14  emit light when the arrow  1  is accelerated by the bow.  
         [0048]     This light emission control part  7  is installed by resin molding inside the housing case  17  integrally attached to the nock main body  16 . At the arrow  1  front end side inside the housing case  17 , an acceleration switch  8  is provided so that its base end is fixed by resin molding. Herein, the acceleration switch  8  is provided in which two thin metal plates  15 A and  15 B are turned toward the arrow advancing direction and their front ends are separated from each other.  
         [0049]     To the acceleration switch  8 , as described in detail in the example of the arrow with the light emitting function to which the invention is applied, the lithium battery  12 , the capacitor circuit  11  including the capacitor  9  and the resistor  10 , the transistor  13 , and the LED element  14  are connected.  
         [0050]     This LED element  14  is fixed by a molding resin inside the nock main body  16 .  
         [0051]     The nock main body  16  is formed from a material that transmits light emitted from the LED element  14 .  
         [0052]     In addition, the nock  3  formed by the nock main body  16  and the housing case  17  with the light emission control part  7  installed inside is attachable to and detachable from the inside of a rear end opening of the arrow shaft  2  of the arrow  1 .  
         [0053]     Therefore, when the LED element  14  emits light, the light is transmitted through the nock main body  16  and goes outside, whereby the locus of the arrow and the position of shooting the target can be visually checked.  
         [0054]     As described in detail in the example of the arrow with the light emitting function to which the invention is applied, in the acceleration switch  8 , when the arrow is accelerated by the bow, the two thin metal plates  15 A and  15 B bend due to inertia and come into contact with each other to temporarily conduct electricity, and charges the capacitor  9  while making the LED element  14  emit light. Furthermore, after the acceleration of the arrow ends and the arrow turns into constant-speed flight, the metal plates  15 A and  15 B restore due to elasticity of the metal plates and electric conduction is cut off.  
         [0055]     Next, electricity charged in the capacitor  9  is discharged through the transistor  13  to make the LED element  14  emit light for a predetermined period of time.  
         [0056]     The period of electric conduction between the collector and emitter of the transistor  13  as a period of light emission of the LED element  14  is determined by the period of electric conduction to the base, and can be set by summing the capacitance of the capacitor  9  and the resistance value of the resistor  10 .  
         [0057]     As a material for the nock main body, other than the material that transmits light, any material or any arrangement can be used as long as it realizes a visual check of the light emitted from the LED element, such as a material that is partially transparent or semi-transparent, or an arrangement in that the light emitted from the LED element is irradiated through a hole opened in the nock main body.  
         [0058]     Furthermore,  FIG. 5  is a perspective view showing an example of a light emission control device having a light emitting function to which the invention is applied, and  FIG. 6  is an internal enlarged explanatory view showing the internal mechanism of  FIG. 5 .  
         [0059]     The light emission control device  18  shown herein includes an arrow attaching part  19  from a plastic material formed at a lower portion and a light emission control part housing case  20  integrally joined to the upper portion of the arrow attaching part  19 .  
         [0060]     The arrow attaching part  19  is formed of, for example, a cylinder with a section curved shape smaller than the outer diameter of the arrow shaft  2 . The light emission control device  18  can be firmly attached to the arrow  1  by fitting the arrow attaching part to the outer circumference of the arrow shaft  2  while expanding its diameter against the elastic force of the plastic material.  
         [0061]     At the arrow  1  front end side inside the light emission control part housing case  20 , an acceleration switch  8  is provided. This acceleration switch  8  has a base end fixed by a molding resin and two thin metal plates  15 A and  15 B turned toward the arrow advancing direction and their front ends are separated from each other.  
         [0062]     To the acceleration switch  8 , as described in detail in the example of the arrow with the light emitting function to which the invention is applied, the lithium battery  12 , the capacitor circuit  11  including the capacitor  9  and the resistor  10 , the transistor  13 , and the LED element  14  are connected and fixed by a molding resin.  
         [0063]     The rear end side of the light emission control part housing case  20  is formed from a material that transmits light (for example, a plastic or the like), and at the rear end side of this light emission control part housing case  20 , an LED element  14  is disposed.  
         [0064]     Therefore, as described in detail in the example of the arrow with the light emitting function to which the invention is applied, in the acceleration switch  8 , when the arrow is accelerated by the bow, the two thin metal plates  15 A and  15 B bend inward due to inertia and come into contact with each other to temporarily conduct electricity, and charge the capacitor  9  while making the LED element  14  emit light. Furthermore, after the arrow leaves the bow, the metal plates  15 A and  15 B restore due to elasticity of the metal plates and cut off the electric conduction, however, the electricity charged in the capacitor  9  is discharged through the transistor  13 , and makes the LED element  14  emit light for a predetermined period of time, whereby it becomes possible to visually check the locus of the arrow and the position where the arrow hits the target or ground.  
         [0065]     The arrow attaching part of the light emission control device, attachable to and detachable from the arrow, does not always need to have the mechanism described in detail in this embodiment, but may have any mechanism as long as it realizes firm and easy attachment, such as a mechanism in which the arrow shaft is inserted through a cylindrical member that is made of a rubber material smaller than the outer diameter of the arrow shaft.  
         [0066]     In addition, as a material of the light emission control part housing case, other than the material that transmits light, any material or any arrangement can be used as long as it enables a visual check of the light emitted from the LED element, such as a material that is partially transparent or semitransparent, or an arrangement in which the light emitted from the LED element is irradiated through a hole opened in the rear end.  
         [0067]     In addition, the battery is not limited to a lithium battery, and for example, cadmium or alkali batteries can be used, however, a lithium battery that is light in weight and enables downsizing is most preferable.  
         [0068]     Furthermore, an arrow to be used for kyudo is described in detail in the embodiment of the invention, however, the invention is also applicable to arrows of archery, bowgun (crossbow), darts, etc., as well as kyudo.  
         [0069]     According to the invention constructed as described above, the acceleration switch is turned on by an acceleration applied when the arrow is accelerated by the bow, and the capacitor is charged while making the LED element emit light. Therefore, a shooter can visually check the locus of the arrow even at dusk.  
         [0070]     In addition, even when the arrow leaves the bow, the acceleration ends, and the acceleration switch is turned off, light is emitted for several seconds by the LED element by discharge from the capacitor, whereby a shooter can confirm the arrow arrival point, easily judge which direction he/she should discharge the arrow in, and concentrate on the training without losing his/her rhythm.  
         [0071]     On the other hand, in matches, the point where the arrow hits can be easily confirmed from a distance, so that a judge can score points from a distance and smoothly advance the match.  
         [0072]     Furthermore, the nock is attachable to and detachable from the arrow main body, so that by providing the nock on an existing arrow that a shooter has used, the existing arrow can be used without change. In addition, the light emission control device is attachable to and detachable from an existing arrow, so that a shooter can attach it to an existing arrow when he/she needs it.  
         [0000]     Description of Symbols  
         [0000]    
       
           1  Arrow  
           2  Arrow shaft  
           3  Nock  
           4  Arrowhead  
           5  Fletchings  
           7  Light emission control part  
           8  Acceleration switch  
           9  Capacitor  
           10  Resistor  
           11  Capacitor circuit  
           12  Lithium battery  
           13  Transistor  
           14  LED element  
           15 A,  15 B Metal plate  
           16  Nock main body  
           17  Housing case  
           18  Light emission control device  
           19  Arrow attaching part  
           20  Light emission control part housing case