hereinafter , the construction and operating principles of the present invention will be described in detail with reference to the attached drawings . fig3 is a perspective view of a device 100 for transmitting a bow string release signal , according to an embodiment of the present invention . fig4 a through 4c are views illustrating the operation of the bow - string - release - signal transmitting device 100 according to the present invention . fig5 is a schematic view showing an example of the construction of a switching means of the bow - string - release - signal transmitting device 100 according to the present invention . fig6 is of views showing the internal construction of the bow - string - release - signal transmitting device 100 and a bow - string - release - signal receiving device 200 according to the present invention a bow string release according to the present invention includes the bow - string - release - signal transmitting device 100 and the bow - string - release - signal receiving device 200 which are provided in a pair and correspond to each other . the bow - string - release - signal transmitting device ( 100 , hereinafter referred simply to as the release signal transmitting device ) is of the shape of a mouthpiece . preferably , the release signal transmitting device 100 includes an upper mouthpiece 101 which is mounted to the upper teeth of a user , and a lower mouthpiece 102 which is mounted to the lower teeth of the user . a first push unit 111 and a second push unit 121 are provided on the upper mouthpiece 101 at positions spaced apart from each other by a predetermined distance in positional sequence from the rear to the front . in the same manner , a first pressure receiving unit 112 and a second pressure receiving unit 122 are provided on the lower mouthpiece 102 at positions spaced apart from each other by a predetermined distance in positional sequence from the rear to the front . the first push unit 111 and the first pressure receiving unit 112 are located in positions at which they come into contact with each other when the upper and lower teeth of the user engage with each other . the locations of the second push unit 121 and the second pressure receiving unit 122 are determined in the same manner . in other words , when the user closes the mouth so that the upper and lower mouthpieces 101 and 102 that are mounted to the user &# 39 ; s teeth engage with each other , the first push unit 111 comes into contact with the first pressure receiving unit 112 and the second push unit 121 subsequently comes into contact with the second pressure receiving unit 122 . a pair of the first push unit 111 and the first pressure receiving unit 112 refers to a first switching means 110 . a second switching means 120 designates a pair of the second push unit 121 and the second pressure receiving unit 122 . although this embodiment of the present invention has two switching means , it may have a single switching means as necessary . in other words , only the first switching means 110 may be provided on the mouthpieces 101 and 102 . if two switching means are provided as in this embodiment including the first and second switching means 110 and 120 , which are arranged in a line , accidental shooting can be more reliably prevented . that is , the present invention is configured such that while the user closes the mouth and the upper and lower mouthpieces 101 and 102 engage with each other , the first and second switching means 110 and 120 are successively pushed at a distance of time . only when the second switching means 120 is pushed after the first switching means 120 has been pushed can the bow string be released . for this , it is preferable for a protruding length of the first push unit 111 to be longer than that of the second push unit 121 . fig4 illustrates the operation of the switching means 110 and 120 according to the angle at which the upper and lower mouthpieces 101 and 102 engage with each other . as shown in fig4 b , when only the first switching means 110 is turned on , a lamp or buzzer that is attached to a device for receiving a bow string release signal that will be explained later herein is operated to signal to be in a standby mode . when the second switching means 120 is also turned on after the first switching means 110 has been turned on , the bow string is eventually released so that an arrow is shot . as shown in fig5 , the first and second pressure receiving units 112 and 122 may be configured such that when each of the second push units 111 and 121 pushes the corresponding pressure receiving unit 112 , 122 , the pressure receiving unit 112 , 122 elastically moves backwards in a casing 113 while overcoming the elastic force of an elastic means 114 installed in the casing 113 . in this case , the push unit 111 , 121 can be prevented from damaging the teeth when pushing the pressure receiving unit 112 , 122 , and the switching means can be more smoothly operated . as shown in fig6 , each of the first and second switching means 110 and 120 , in particular , each of the first and second pressure receiving units 112 and 122 , has a switching element 112 a , 122 a , a battery 112 b , 122 b and a signal transmitter 112 c , 122 c . each switching element 112 a , 122 a may comprise a known switching element , such as a contact or pressure point switch or the like . any type signal transmitter may be used as each signal transmitter 112 c , 122 c , so long as it can transmit an on or off signal pulse to a bow - string - release - signal receiving device ( 200 , hereinafter referred to as a ‘ release signal receiving device ’) through wire / wireless communication . the release signal receiving device 200 includes a signal receiver 201 which receives a release signal , a battery 202 which supplies power , a controller 203 which analyzes the release signal of the signal receiver 201 and transmits a control command , and an actuator 204 which receives the control command and is operated in response to the control command . the actuator 204 may comprise any shape or structure of device , such as a linear motor , a step motor , a relay , a limit switch , etc ., so long as it can linearly move or rotate so that the bow string can be released . fig7 is a view showing the construction of a shooting unit 210 of the release signal receiving device 200 , according to an embodiment of the present invention . fig7 illustrates an example of the construction of the actuator that has received a control command . in this embodiment , two rollers 212 a and 212 b are provided in the release signal receiving device 200 , and a bow string 10 is held by rear portions of the rollers 212 a and 212 b . the upper roller 212 a of the two rollers 212 a and 212 b is retained by a link bar that refers to a string holder 213 . a lower end of the string holder 213 is connected to a linear actuator 214 . when the release signal receiving device 200 receives a release signal , the linear actuator 214 is operated and moved linearly downwards . then , the string holder 213 rotates around a pivot 213 a . the upper roller 212 a is eventually lifted . as a result , the bow string 10 can be smoothly released without resistance . a linear motor or a linear slide device may be used as the linear actuator 214 . in the drawing , the reference numeral 214 b denotes a slide rail , and 214 a denotes a slider that linearly moves along the slide rail 214 b . further , the reference numeral 211 denotes a housing of the release signal receiving device 200 . in fig7 , the remaining elements of the release signal receiving device 200 are omitted for the sake of convenience of the description . in the bow string release of this embodiment , to pull the bow string , the slider 214 a moves downwards so that the upper roller 212 a is lifted . after the user inserts the bow string into the shooting unit 210 through the space between the rollers 212 a and 212 b , the linear actuator 214 moves upwards again so that the bow string is held by the rollers 212 a and 212 b . subsequently , as described above , when two successive switching on signals are received from the first and second switching means 110 and 120 , the bow string is released . in the present invention , the user has the bow string release with the bow string held by the release signal receiving device 200 and , when necessary , for example , when game appears , the user immediately turns on the power of the release signal receiving device and then releases the bow string at a proper moment , thus shooting an arrow . although power switches of the release signal transmitting device 100 and the release signal receiving device 200 have not been illustrated in the above description , each of the devices 100 and 200 has a power switch . therefore , even when the user is gripping the mouthpiece type transmitting device in his / her mouth , if it is unnecessary , the release signal transmitting device 100 or the release signal receiving device 200 may be turned off . in other words , even though the user is gripping the transmitting device in his / her mouth , it can be used only when necessary so that an arrow is shot . if such a power on / off function is applied to a hunting bow , it can be very conveniently used . for example , the user always maintains the bow string in a state of having been held by the string holder 213 of the release signal receiving device 200 and searches for game while the release signal transmitting device 100 or the release signal receiving device 200 is being turned off . as soon as the user finds out a target , he / she can turn on the device 100 or 200 and shoot an arrow without needing to put the bow string to the held position again . the power switch functions as a kind of safety device . the power switch may be configured such that when the bow string is pulled after the bow string has been put in the release signal receiving device 200 , the power switch is turned on . as described above , in the present invention , a switching element of a mouthpiece gripped in the mouth of a user determines whether shooting an arrow . compared to when the user controls a bow string release with his / her hand and determines the shot of an arrow , the present invention can markedly reduce the shaking of the bow string and remove a probability of accidental shooting , thus enhancing safety . furthermore , the present invention can be used in an extensive range of bows , for example , for leisure , sports , training the mind and body , hunting , etc . in particular , in the case where the present invention is used in a bow for hunting , a shooting accident can be prevented from occurring while searching and pursuing game . although the preferred embodiments of the present invention have been disclosed for illustrative purposes , those skilled in the art will appreciate that various modifications , additions and substitutions are possible , without departing from the scope and spirit of the invention as disclosed in the accompanying claims .