Patent Publication Number: US-10309743-B2

Title: Triggering mechanism for hybrid primer cartridges

Description:
BACKGROUND OF THE INVENTION 
     The present invention is in the technical field of firearms. More particularly, the present invention is in the technical field of electronic and electro-mechanical triggering mechanism used in handheld or mounted gun systems. 
     Conventional firearm&#39;s triggering mechanism (such as those used in the handheld or mounted gun) largely use only mechanical power to strike on the percussion cup in the centerfire cartridges. 
     Few conventional guns do use electrical power applied using the firing pin or fixed electrode on the face of the bolt to central percussion cup primer. Systems for electrically igniting the propellant charge in gun-fired ammunition have long been known in the prior art. For example, the U.S. Pat. No. 3,748,770 describes one such arrangement where the bolt consists of a fixed central firing pin acting as a power contact to fire the primer having an electrically conductive priming mixture in the percussion cup. This system cannot be used to fire the electrodes of a Hybrid primer because they are not located inside the percussion cup but are arranged in an insulated base around it. Similar to the U.S. Pat. No. 3,748,770 there are other patents (for example, U.S. Pat. No. 5,755,056A) which aim to trigger the centrally located primer in percussion cup using energized firing pin. In U.S. Pat. No. 5,329,840 the  FIG. 1  explains the working of such systems. 
     These firearms however do not have the triggering mechanism to fire the Hybrid Primer cartridges since applying the electric power to the percussion cup in a Hybrid primer will not energize the electrodes around it which are the key to achieve multiple triggering points within the cartridge case. The Hybrid Primer referred here is a new patented primer design (U.S. Pat. No. 9,546,857) which consists of a centrally located conventional pressure-sensitive chemical primer housed in a percussion cup surrounded by electrical primer consisting of insulating base housing multiple electrode pins of varying lengths housed in the holes or slots in the base (similar to bristles of a tooth-brush). When high-voltage electrical pulses are applied on these electrodes then the plasma or electric arcs are generated at multiple points along the length of the cartridge burning the propellant efficiently. 
     SUMMARY OF THE INVENTION 
     The present invention discusses in detail the multiple ways to trigger the Hybrid primer in a firearm either by turning the set of electrode pins as a pair to generate the plasma i.e., electric arc between them (two-wire system) or to convert the cartridge case itself as one of the electrode and the electrode pins as the electrode of opposite polarity (one-wire system). The present invention is an enhancement of the conventional firearm like single barrel or multi-barrel firearm or grenade launcher etc., with modified chamber, bolt and switches activated by trigger or hammer or a combination of the mentioned components (with or without microprocessor/microcontroller unit and associated sensors or position encoders). The electric power is supplied through the chamber and passed to the bolt when in locked position however the current flow is controlled by the switched activated by the hammer/striker. Also discussed here is an alternate way to use a modified hammer and firing pin combination as part of electrical circuit which can fire the Hybrid primer cartridge through the application of high-voltage electric power pulses to the modified bolt or just the striker to directly apply the electrical power on the Hybrid primer. These modified components, individually or as a combination, enable the firearm to be fired in three modes (with respect to the functioning of firearm): the conventional mechanical mode, electro-mechanical/hybrid mode and the electric only mode. With respect to the triggering of the Hybrid primer cartridge these modes can be classified as the conventional chemical-primer mode, the hybrid-primer mode and the electric-primer mode. This application further details the solutions on how to upgrade various components like the chamber, bolt, hammer, firing-pin, trigger etc., in the conventional firearms economically so that they can fire the cartridges employing the Hybrid Primer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIGS. 1( a ) and ( b )  are perspective views of the hybrid bolt which can supply very high-voltage low-current electric pulses to the Hybrid primer&#39;s electrodes through the power contacts on its lugs to the contacts on the face of the bolt connected via insulated wires. The bolt also allows the chemical primer to be triggered mechanically using the firing pin. 
         FIG. 1( c )  shows the bolt&#39;s power supply input contacts, the insulated connecting electrical wires and the contacts on the face of the bolt as part of the two-wire system and  1 ( d ) shows the contacts on the bolt face applying electric power to the hybrid primer base; 
         FIGS. 2( a ), ( b ), ( c ) and ( d )  shows the barrel-chamber with the locking chamber modified such that electric power pulses can be supplied to the primer via the bolt when it is in the locked position in the chamber; and 
         FIGS. 3( a ) and ( b )  show how the trigger and the hammer can be used to control the electrical trigger.  FIG. 3( c )  shows the hybrid hammer which can allow the electric power pulses through it when its contacts are pressed against the contacts on the bolt or alternately through the firing-pin. 
         FIG. 4( a )  shows a bolt&#39;s aft designed to receive the electric power supply from a hybrid hammer&#39;s contacts so as to receive the power from the hammer and transfer it to the bolt, and  FIG. 4( b )  shows a firing pin which has contacts in the rear (instead of the bolt&#39;s aft) to receive electric power via the hybrid hammer and transfer the electric power to the bolt&#39;s face or directly to the primer via provisioned hole in the bolt; 
         FIG. 5( a )  shows the rear view of a firearm with a rotating chamber, and  FIG. 5( b )  the front view of a striker which will directly fire the Hybrid primer both mechanically and electrically. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the invention in more detail, in  FIG. 1( a )  is shown the bolt which is modified to receive the high-voltage electric pulses through contact points ( 109 ,  110 ) on the bolt&#39;s locking lugs. When the bolt is in the locked position it will receive the electrical power via the contacts in the chamber and transfers it to the Hybrid primer through the contacts ( 107 ,  108 ) on the face of the bolt; wherein the contacts on the face of the bolt and those on the lugs are connected by insulated wires or bus. The locking lugs may be detachable from the bolt and made of material which has high heat and electrical resistance or may be covered by one or more layers of electrical and heat resistant insulating tapes. The contact points are surrounded with sufficient thickness of electrical insulation so that the electric current does not leak to the bolt or other parts of the firearm. 
     The front portion of the bolt or the whole bolt itself may be made with materials that can resist the very high-voltage low-current power supply as well as be capable of resisting heat and withstand high pressure (like polyamide polymers, fiber-glass, ceramics, nylon 66 based composite compounds, etc.);  FIG. 1( b )  shows one such design where front of the bolt is made using an insulated material (shown in shaded pattern). 
       FIG. 1( c )  shows the lug contact points ( 109  and  110 ) connected to the primer contact points ( 107  and  108 ) connected using the insulated electrical wires ( 111  and  112 ). 
     In a two-wire system the distance between the power contacts on the face of the bolt ( 107  and  108 ) is greater than the diameter (or width) of the primer&#39;s electrode base contact points to prevent short circuit. In  FIG. 1( d )  a representative diagram of primer base is shown where the hybrid primer&#39;s electrode pin base contacts are shown in circles (in an 8 pin configuration) arranged in a circular plane equidistant from each other; each of the bolt&#39;s primer contacts  107  and  108  are designed to contact at least one of these electrodes. The plasma or electric arc is shown originating from electrodes  4 ,  6  and also  5  (which are in contact with the bolt&#39;s power contact point  107 ) and ending at the electrode  1  (which is in contact with  108  power contact point on the bolt). 
       FIG. 2( a )  shows a chamber modified to have power supply contacts ( 204  and  205 ) fixed on the locking section ( 203 ) of the chamber such that when the bolt is in the locked position the bolt will contact the power points thus completing the electric circuit when the trigger is pulled, allowing the current from the application high-voltage electric power pulses to flow from the supply to the primer. 
     Applying electric power through the locking chamber and bolt instead of the firing-pin allows the manufacturers to design the firearm to fire in pure electrical mode minimizing the mechanical vibrations resulting in improved accuracy. 
       FIG. 2( b )  shows another example of chamber supplying electric power but with moving power contact parts. The chamber contacts  204  and  205  are movable parts which will be pushed out by the locking lugs when the bolt is in locked position; these contacts will then come in contact with the fixed contact points  206  and  207  respectively; hence the current flows through the contacts when the electric circuit is completed. When the bolt is unlocked, the contacts return to the original position pushed by the springs ( 208  and  209 ). 
       FIG. 2( c )  shows the chamber ( 202 ) loaded with a Hybrid primer cartridge  212  and is locked into position by a bolt ( 101 ). The bolt ( 101 ) consists of the firing pin ( 214 ) which triggers the chemical primer in percussion cup ( 215 ) using mechanical strike applied by a hammer. The bolt shown in this figure is in locked position with its locking lugs having the electrical contact points  109  and  110  pressed against the locking chamber&#39;s electrical supply points  205  and  204  respectively which completes the electrical circuit when the trigger switch is closed i.e., switched ON. When the electrical power pulse is applied through the locking chamber supply contact ( 204 ), the current travels through the locking lug&#39;s contact  110 , the connecting wire  112  and is then applied to the electric primer&#39;s long and short electrode pin pairs ( 212  and  213 ) via contact  108 ; the current jumps in the form of plasma channel or spark created between the anode and cathode electrode pins and then returns through the contact point  107 , the connecting wire  111 , locking lug contact point  109  and returns to the electrical ground or terminal point through the chamber&#39;s contact  205 . When the trigger is squeezed, an electrical switch called the ‘Trigger switch’ or a switch controlled by hammer movement called ‘Hammer Switch’ will be closed which allows the flow of electric current to the chamber. 
     To control the rate of fire in the firearm (like single burst, three burst or full automatic mode etc.), without any mechanical movement of the hammer and firing-pin, a microcontroller/microprocessor based electronic control system may be used which can sense user inputs like the position of the trigger, the selector and also sense the position of the bolt which can then be used to control a solid state electronic switch which in turn controls the application of electric power to the primer. 
       FIG. 2( d )  shows the firearm in ‘one-wire setting’ where the bolt applies the same electric polarity through its contacts on the primer and the conducting chamber-barrel assembly is connected to the ground or returning point of the electrical circuit. When power is applied to the Hybrid primer electrodes via the bolt contact point, the electrons jump from the electrodes to the conducting cartridge case (forming the electric arc) and return via the chamber completing the circuit (or vice versa based on polarity of the power applied). The primer electrodes pins are arranged such that the electrical resistance at the gaps ( 216 ) of long &amp; short pins and the cartridge case allow current to flow equally through all the points so that electrons can jump from the pins to the case creating the plasma which will burn the propellant. The cartridge case acts as one of the electrode hence the distance between the short pins and case is greater than the distance between the longer pins and the case such that equal currents flow through long and the short pin paths. 
     When the fireafin is set to fire in the pure electrical mode the hammer can be locked, as shown in  FIG. 3( a )  by a selector switch ( 303 ) with lever locking the hammer ( 302 ) in place and the cartridge can be fired using the electronic firing through the chamber. Firing in electrical mode can improve accuracy by eliminating the vibration due to the movement and strike impact of the hammer on the firing pin. The electrical trigger switch is shown with the supply input contact  305  which is connected to the power supply, the output contact  306  is connected to the high voltage generating circuit which in turn is connected to the locking chamber contacts. When the trigger  301  is pulled then the switch spring  307  will close the electrical circuit by pushing the contact  304  to connect the input and output contact ports ( 305  and  306  respectively). 
     In  FIG. 3( b )  an alternate electro-mechanical design is shown. Here a combination of two electrical switches activated by the trigger and the hammer respectively is utilized. The mechanical movement of the trigger and the hammer is used to close the electrical circuit and connect the power source like battery (or alternator) to the high-voltage pulse generator circuit thus allowing the single, triple and full auto etc., firing modes achieved in a mechanical arrangement to be also converted into electrical triggers without having to use any sensitive electronic microcontroller/microprocessor control processor and sensor units. In the  FIG. 3( b )  is shown an electrical switch called the hammer switch that is closed whenever the hammer is released. When the trigger is pulled and the hammer is released then the hammer contacts the switch when the hammers projected lower part  312  compresses the switch thereby connecting the contacts  309  and  310  via  308 . When the hammer is cocked then the spring  311  with push the connector  308  back breaking the circuit. The switch explained in this diagram is just an example and any electrical switch may be used here. For example, the point  312  in the hammer if made of conducting metal (and properly insulated, to avoid leakage) can be used to connect the points  309  and  310  to complete the circuit whenever the hammer is released; when the hammer is cocked then the points  309  and  310  may be separated by insulation. The points  309  and  310  may be arranged in a plane perpendicular to the hammer point  312 . The manufacturers may arrange the Trigger switch and the Hammer switch in parallel, with a selector switch, that separates the electro-mechanical mode and the electrical mode. 
     In the modern battlefield there is increasing risk of sensitive electronics getting destroyed by E.M.P (Electro Magnetic Pulse) radiation attack thus the use of more robust electro-mechanical arrangement is recommended so that soldiers or law enforcement personnel are not at a disadvantage. 
       FIG. 3( c )  shows the perspective view of the Hybrid hammer which is used to apply mechanical strike on the firing pin but can also supply electric power to the cartridge through the bolt. The hybrid hammer is shown having the electrical contacts  308  and  309  placed in the insulated case on either side of the hammer which may act like switch. The port  310  is provided for the insulated connecting wire that supplies the high-voltage electrical power pulse and similarly the return wire is provided on the other side. To use the hybrid hammer the bolt will have to be modified to receive the power from the rear. 
       FIG. 4( a )  shows the aft face of a bolt designed to accept the power supply from the hybrid hammer shown in  FIG. 3( c ) . The bolt  401  has the firing pin  402  to strike the chemical-primer; it also has the electric power supply points  403  and  404  which receive the power from the hybrid hammers contacts ( 313  and  314 ). The supply points  403  and  404  are surrounded by layer of electrical insulation (shown in shaded pattern as  405  and  406 ). The bolt can alternately receive the power from the contacts placed on the sides ( 407  and  408 ) with the help of hammer or external contacts like a metal brush wherein the external metal brush or contact&#39;s power supply is controlled by a CPU or Hammer controlled switch. 
     The electric power contacts that accept the power from the Hybrid hammer can be either part of the bolt or they may be designed to be part of the firing pin.  FIG. 4( b )  shows a firing pin with electric power contacts ( 409  and  410 ) in the rear face capable of receiving power from the hybrid hammer&#39;s contacts ( 313  and  314 ). When the hammer hits and is pressed against the firing pin then the firing pin&#39;s contacts ( 409  and  410 ) will be in connection with the bolt&#39;s contacts ( 107  and  108 ) hence the electric current will flow through these contacts to the primer, triggering the live cartridge. The bolt alternately can have slots that allow the power contacts on either side of the firing pin to directly contact the Hybrid primer&#39;s electrodes&#39; base contacts. 
       FIG. 5( a )  shows the back view of a rotating chamber in a firearm with a Hybrid primer cartridge in one of the chambers. The firearms with rotating chamber typically do not have bolt and firing pin instead they have a striker that will directly hit the percussion cap. 
       FIG. 5( b )  shows the front view of a striker with the electric power contacts on either side. The pointed edge ( 505 ) in the center will strike the percussion cap housing the chemical primer whereas the power contacts ( 504  and  506 ) will apply the electric power on the electrode pins and trigger the propellant by creating the electric arcs within the case at multiple trigger points. If the chamber is made of conducting material like metals then the same design can be converted into a one wire system with the chamber connected to the ground. The single or multiple barrel may be fixed (like grenade launcher) or may be part of the chamber rotating together (like Gatling gun). 
     The firearm will work in the conventional mechanical mode when the electric power supply is disconnected or switched off. 
     Using the techniques detailed in this application individuals or manufacturers practicing the art of producing firearms can quite comfortably upgrade the existing firearms to fire the electro-chemical Hybrid Primer cartridges.