Abstract:
A remote pyrotechnic ignition system includes a power supply for producing an electrical current in a transmitting induction coil to induce an electrical current in a receiving induction coil for igniting a pyrotechnic device. Thus, a wireless ignition communication section allows pyrotechnic mortars to be reused and substantially reduces set-up time by eliminating the wiring of fireworks normally required for a pyrotechnic production. Optionally, a capacitor is charged by the power source via a charging circuit and discharged via a firing circuit to produce the electric current in the transmitting coil in a pulse. The capacitor provides a two-stage firing safety feature. An electronic control device such as a circuit board may be mounted on the pyrotechnic device for controlling ignition of the pyrotechnic device and is especially useful in controlling ignition sequencing and overall ignition timing of a lift charge and burst charge of the pyrotechnic device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Application Ser. No. 60/708,935 filed Aug. 17, 2005; the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The invention relates generally to a remotely controlled ignition system for pyrotechnic devices. More particularly, the invention relates to such a control system which is capable of wirelessly igniting pyrotechnic devices. Specifically, the invention relates to such a system where ignition is accomplished via electromagnetic induction. 
         [0004]    2. Background Information 
         [0005]    Ignition systems for fireworks or pyrotechnic devices are within three primary categories, namely manual firing, electrical firing and digital firing. Manual firing is the age-old process of igniting a fuse with a torch or some sort of hand lighter whereby a flame is the catalyst for igniting the fuse. In more recent decades, electrical firing has been utilized wherein an electrical ignitor known as an E-match or squib is inserted into the fuse or black powder of the pyrotechnic device so that an electrical current initiates the ignition of the fuse or black powder. Digital firing also involves the use of E-matches which are connected in the same manner to the pyrotechnic device and are also wired to a computer system in order to automatically shoot the fireworks. The digital systems are very expensive and are typically used with pyro-musical productions. 
         [0006]    The typical firework or pyrotechnic show or production typically involves the shooting of from 100 to 40,000 pyrotechnic devices. While manual firing is still the least expensive method of igniting pyrotechnic devices, the manual firing method presents obvious safety issues from the inability to ignite the fireworks remotely. While the electrical and digital firing methods provide for remote ignition of the pyrotechnic devices, nonetheless each firework requires one E-match. The labor for wiring each of these E-matches to the firing system is very time-consuming and cumbersome, and results in many wires disposed above the firing mortars of the pyrotechnic devices. It has been estimated that approximately half of the labor of setting up a pyrotechnic show is due to the wiring of these devices. 
         [0007]    In addition, aside from the digital firing systems, there is a need within the pyrotechnic industry for a control mechanism to control the ignition of the lift charge and the burst charge of a pyrotechnic device, in particular the firing sequence thereof. The present invention addresses these and other problems within the art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention provides a pyrotechnic ignition system comprising an electric power source; a pyrotechnic device; an ignition communication pathway from the power source to the pyrotechnic device; wherein the pathway includes an electrical conductor in electrical communication with the pyrotechnic device; and a wireless portion intermediate the power source and the conductor along the pathway; wherein the pyrotechnic device is selectively ignitable via the pathway in response to an electric current produced by the power source. 
         [0009]    The present invention also provides a method comprising the steps of sending an electric signal along a communication pathway which includes a wireless portion; and igniting a pyrotechnic device in response to the electric signal. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0010]    Preferred embodiments of the invention, illustrative of the best modes in which applicant contemplates applying the principles, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended claims. 
           [0011]      FIG. 1  is a diagrammatic view of the ignition system of the present invention including a sectional view of the mortar and the transmitting induction coil with a first embodiment of the pyrotechnic device of the present invention disposed within the mortar. 
           [0012]      FIG. 2  is an enlarged sectional view of the first embodiment of the pyrotechnic device as viewed from the side. 
           [0013]      FIG. 3  is an enlarged fragmentary view of a portion of  FIG. 1  showing the mortar and first embodiment of the pyrotechnic device in section prior to ignition of the device. 
           [0014]      FIG. 4  is similar to  FIG. 3  and shows the lift charge and timing fuse having been ignited and the pyrotechnic device at an early stage of launching. 
           [0015]      FIG. 5  is similar to  FIG. 4  and shows the timing fuse at a subsequent stage of burning and the pyrotechnic device at a subsequent stage of launching. 
           [0016]      FIG. 6  is similar to  FIG. 2  and shows a second embodiment of the pyrotechnic device of the present invention. 
           [0017]      FIG. 7  is similar to  FIG. 3  and shows the second embodiment. 
           [0018]      FIG. 8  is similar to  FIG. 7  and shows that the first charge and timing fuse have been ignited with the pyrotechnic device at an early stage of launching. 
           [0019]      FIG. 9  is similar to  FIG. 8  and shows the timing fuse at a further stage of burning and the second embodiment pyrotechnic device at a further stage of launching. 
           [0020]      FIG. 10  is an enlarged fragmentary view similar to a portion of  FIG. 1  and shows a third embodiment of the pyrotechnic device of the present invention. 
           [0021]      FIG. 11  is similar to  FIG. 10  and shows a fourth embodiment of the pyrotechnic device of the present invention. 
           [0022]      FIG. 12  is similar to  FIG. 11  and shows a fifth embodiment of the pyrotechnic device of the present invention. 
           [0023]      FIG. 13  is a diagrammatic view showing a sixth embodiment of the ignition system of the present invention set up for shooting a plurality of pyrotechnic devices. 
       
    
    
       [0024]    Similar numbers refer to similar parts throughout the specification. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    A first embodiment of the ignition system of the present invention is indicated generally at  100  in  FIGS. 1-2 ; a second embodiment is indicated generally at  200  in  FIGS. 6-7 ; a third embodiment is indicated generally at  300  in  FIG. 10 ; a fourth embodiment is indicated generally at  400  in  FIG. 11 ; a fifth embodiment is indicated generally at  500  in  FIG. 12 ; and a sixth embodiment is indicated generally at  600  in  FIG. 13 . Each of said ignition systems is configured to remotely ignite pyrotechnic devices. 
         [0026]    With reference to  FIG. 1 , ignition system  100  includes an ignition control  102  and an ignition communication pathway  104  in communication with control  102  for igniting or shooting a pyrotechnic device  106  from a firework mortar  108  disposed on a launch surface  110 , which may be the ground or any other suitable structure known in the art. Control  102  includes a power supply  112 , a charge button  114 , a fire button  116  and an on/off key switch  118 . Communication pathway  104  includes a control cable  120  having a charging circuit and a triggering circuit, a capacitor  122 , a transmitting induction coil or induction member  124 , a susceptor in the form of a receiving induction member or coil  126 , an electromagnetic field region or wireless portion  128 , an electronic control device in the form of a circuit board  130  and an E-match ignition device  132  ( FIG. 2 ). Transmitting induction coil  124  is encased in a waterproof annular housing  134  which is typically over molded onto coil  124  and includes electronic shielding. Mortar  108  includes a mortar tube  136  which is typically cylindrical and a mortar plug  138  disposed within tube  136  adjacent a bottom end thereof. Pyrotechnic device  106  is seated atop mortar plug  138  within mortar tube  136  and is further described below. 
         [0027]    Power supply  112  of control  102  is typically in the form of a battery or batteries although other power sources may be used. Charge button  114  is an electric switch for selectively opening and closing the charging circuit of control cable  120  for selectively charging capacitor  122 . Fire button  116  is also an electrical switch for selectively opening and closing the triggering circuit of control cable  120  to selectively discharge capacitor  122 . Thus, the charging circuit and triggering circuit of control cable  120  are in electrical communication with capacitor  122 , which is in electrical communication with induction coil  124 . Coils  124  and  126  are spaced from one another by wireless portion  128  of communication pathway  104  and by a portion of mortar tube  136 . Each of coils  124  and  126  are substantially cylindrical although this may vary. Receiving coil  126  is in electrical communication with circuit board  130  which is in electrical communication with ignition device  132  ( FIG. 2 ). Coils  124  and  126  are part of an electromagnetic induction assembly whereby an electric current flowing through coil  124  produces an electromagnetic field to induce an electric current in receiving coil  126 . 
         [0028]    Preferably, housing  134  has an inner surface  140  which is of a mating configuration with an outer surface  142  of mortar tube  136 . It is preferred that housing  134  is slidable over mortar tube  136  while inner surface  140  is in frictional engagement with outer surface  142  to a degree which allows this slidable characteristic while also allowing housing  134  to be positioned on tube  136  and held in place simply by the frictional engagement therebetween. However, housing  134  may be held in position on tube  136  by any securing mechanism known in the art. Mortar tube  136  has a sectional width or diameter D 1 , transmitting coil  124  has a sectional width or diameter D 2  which is greater than diameter D 1  and receiving coil  126  has a sectional width or diameter D 3  which is less than diameter D 1 . Diameter D 1  of mortar tube  136  typically ranges from approximately 2 inches to 24 inches. The diameters of mortar tubes  136  which are commonly in use include 2″, 2.5″, 3″, 4″, 5″, 6″, 8″, 10″, 12″, 16″ and 24″. Depending on the diameter D 1  of tube  136 , diameters D 2  and D 3  will vary accordingly. 
         [0029]    Transmitting coil  124  is configured to be tuned to a specific frequency or narrow frequency range and receiving coil  126  is likewise configured so that the frequency or narrow range of each of coils  124  and  126  are matched in order to only allow the proper pyrotechnic device to be fired. Thus, for instance, if a pyrotechnic device of the wrong size is placed in mortar tube  136  and thus has a receiving coil  126  which is not matched in frequency to transmitting coil  124 , an electrical current will not be induced in receiving coil  126  when an electrical current is passed through transmitting coil  124  and the improper pyrotechnic device will not be ignited, or an insufficient current will be produced in coil  126  for igniting such a device. Mortar tube  136  is formed of a non-metallic material in order to allow the electromagnetic field produced by the electric current within transmitting coil  124  to pass through tube  136  and induce an electrical current within receiving coil  126 . Typically, mortar tube  136  is formed of a fiber composite material although this may vary. 
         [0030]    With reference to  FIG. 2 , pyrotechnic device  106  is further described. Device  106  includes a lift charge chamber  144  and a star chamber  146  disposed above and mounted on lift charge chamber  144 . Lift chamber  144  contains a lift charge  148  which is typically in the form of black powder and star chamber  146  contains pyrotechnic color stars  150  for producing the color displays commonly associated with a fireworks show. Device  106  further includes a burst charge  152  disposed within star chamber  146  and a timing fuse  154 . Timing fuse  154  may be an E-match for electrically igniting burst charge  152 , or may be a burning-type fuse or a combination thereof.  FIG. 2  shows timing fuse  154  as a first fuse  156  and a second fuse  158  in the form of a black match. First fuse  156  communicates with ignition device  132  and second fuse  158 , which communicates with burst charge  152 . Thus, second fuse  158  is partially disposed within star chamber  150  and partially disposed within lift chamber  144  while first fuse  156  is disposed entirely within lift chamber  144  along with ignition device  132 . Lift chamber  144  further includes a bottom wall  160  which encases circuit board  130 . 
         [0031]    The operation of system  100  is now described with reference to FIGS.  1  and  3 - 5 . Once system  100  is properly set up, an operator is ready to remotely ignite or shoot pyrotechnic device  106 . With reference to  FIG. 1 , the operator will first turn key switch  118  to an “on” position in order to provide power to system  100  via power source  112 . Charge button  114  is then depressed to close the charging circuit in order to charge capacitor  122 . In order to ignite and shoot pyrotechnic device  106 , fire button  116  is then depressed to close the firing circuit, which discharges capacitor  122  to produce an electrical current within transmitting coil  124 . Due to the nature of the discharge of capacitor  122 , the electrical current only flows for a relatively brief time in a short pulse of energy. The electric current flowing in coil  124  produces an electromagnetic field within mortar tube  136  across region  128  in order to produce an electrical current within receiving coil  126  which flows to circuit board  130  and E-match device  132  ( FIG. 3 ). While the strength of the electrical current within receiving coil  126  may vary, it will likely be on the order of 500 milliamps at 1 volt, typically the power required to ignite an electric ignition device such as device  132 . 
         [0032]      FIG. 3  shows pyrotechnic device  106  prior to the electrical current reaching ignition device  132 . In  FIG. 4 , the electric current has reached and ignited ignition device  132  which in turn has ignited first fuse  156  of timing fuse  154  as well as lift charge  148  whereby device  106  is at an initial stage of lifting or launching upwardly as indicated by Arrow A in  FIG. 4 .  FIG. 4  shows first fuse  156  burning toward second fuse  158  and  FIG. 5  shows second fuse  158  having been ignited and burning in the direction shown at Arrow B toward burst charge  152  as pyrotechnic device  106  continues upwardly as indicated at Arrow C in  FIG. 5 . Thus, pyrotechnic device  106  will have shot upwardly to a desired height when timing fuse  154  ignites burst charge  152  in order to produce the firework display. 
         [0033]    With reference to  FIG. 6 , a firework or pyrotechnic device  202  associated with system  200  of the present invention is described. Device  202  is similar to device  106  except that it has a timing fuse  204  which is connected directly to an alternate circuit board  206  instead of to ignition device  132 . More particularly, timing fuse  204  includes a first fuse  208  and a second fuse  210  connected to one another with first fuse  208  connected to circuit board  206  and second fuse  210  communicating with burst charge  152 . 
         [0034]    With reference to  FIGS. 7-9 , system  200  operates in a similar fashion as that of system  100  except for the control of the ignition via circuit board  206 .  FIG. 7  shows pyrotechnic device  202  prior to the electric current flowing into circuit board  206  and ignition device  132 . Once the firing sequence has been initiated by pushing fire button  116  ( FIG. 1 ), the electrical current produced as described with regard to system  100  flows into circuit board  206  and ignites ignition device  132  in order to ignite lift charge  148  to begin lifting device  202  upwardly as indicated by Arrow D in  FIG. 8 . In contrast to system  100 , circuit board  206  directly controls the ignition of first fuse  208  without the use of ignition device  132 . Thus, circuit board  206  is configured with an electronic timing device which ignites first fuse  208  at a predetermined time with regard to the ignition of device  132 , thus controlling the sequencing of igniting device  132  and timing fuse  204 .  FIG. 8  shows first fuse  208  burning and  FIG. 9  shows second fuse  210  having been ignited and burning toward burst charge  152  as indicated at Arrow E as pyrotechnic device  202  is at a later stage of lifting as indicated by Arrow F. Thus, system  200  uses a different timing device than that of system  100 . The advantages of system  200  allows for the separate control of the sequence of igniting the burst charge and igniting the timing fuse and is particularly suited to the use of an E-match fuse (also represented by  204 ) because the timing of ignition of the E-match fuse may be controlled entirely by circuit board  206 . Thus, for instance, circuit board  206  may be configured to allow ignition device  132  to be ignited immediately upon the flow of current through circuit board  206  and then delay the flow of current to the timing fuse for a period of time so that, for example, pyrotechnic device  202  is substantially at the height desirable for igniting burst charge  152  when an E-match fuse  204  is ignited by circuit board  206 . 
         [0035]    With reference to  FIG. 10 , system  300  is similar to systems  100  and  200  with the primary distinction being the position of capacitor  122 , transmitting coil  124  and a receiving coil  326  which is similar to coil  126 . The only substantial difference between coil  326  and  126  is that coil  326  has a longer lead wire  328  and that coil  326  is mounted on a cylindrical upward projection mounted atop star chamber  146 . Otherwise, the operation of system  300  is the same as either system  100  or system  200 . 
         [0036]    With reference to  FIG. 11 , system  400  is similar to system  300  in that capacitor  122 , transmitting coil  124  and a receiving coil  426  are disposed above star chamber  146  and mounted thereon. In addition, receiving coil  426  is configured in a substantially conical shape and is mounted on a cone-shaped device  430  which is mounted on star chamber  146 . The windings of coil  426  are shown at an angle instead of being perpendicular to the direction of firing of the pyrotechnic device. System  400  thus shows but one example of an alternately-shaped receiving coil to indicate that a receiving coil may be in any suitable shape which allows for the flow of electrical current via the inductive process as previously described. Otherwise, system  400  functions in the same manner as described with regard to either system  100  or  200 . 
         [0037]    With reference to  FIG. 12 , system  500  shows a receiving coil  526  which is cylindrical like those shown in systems  100 ,  200  and  300 . However, receiving coil  526  is elevated toward the top of mortar tube  136  and is not mounted on the pyrotechnic device but is only in electrical communication therewith via a lead wire  528 . Coil  526  is mounted on a cylindrical support  530  which is disposed adjacent an upper end of mortar tube  136 . Capacitor  122  and transmitting coil  124  are shown in an inverted position with respect to the other embodiments although there is no structural change. 
         [0038]      FIG. 13  shows system  600  which includes a plurality of pyrotechnic launching devices each of which may be configured as described with regard to previous embodiments. More particularly, system  600  includes a control  102 A which is similar to control  102  of system  100  except for it is configured for shooting multiple pyrotechnic devices. Unit  102 A includes a charge button  114 A, four fire buttons  116 A-D and a key switch  118 A which are analogous and function in the same manner as described with regard to buttons  114  and  116  and switch  118  of system  100 . Control cables  120 A-D are in electrical communication respectively with fire buttons  115 A-D and each of control cables  120 A-D also is in communication with charge button  114 A. Control cables  120 A-D are also respectively in electrical communication with capacitors  122 A-D which in turn are in electrical communication with transmitting coils (not shown) respectively within housings  134 A-D which are mounted respectively on mortar tubes  136 A-D. System  600  shows the concept of the invention as it would be used with a plurality of pyrotechnic devices. 
         [0039]    In operation, system  600  would operate as described with regard to systems  100  and  200  except that button  114 A would be pushed to close the charging circuit in order to charge all of capacitors  122 A-D associated with the pyrotechnic devices located within mortar tubes  136 A-D, and then fire buttons  116 A-D may be pushed individually to respectively control the ignition of the pyrotechnic devices located respectively within tubes  136 A-D. Each of fire buttons  116 A-D may control the ignition of a single pyrotechnic device or a plurality thereof, for instance a row of such devices. As previously noted with regard to system  100 , each housing  134 A-D includes a shielding device which is important with regard to having the pyrotechnic devices located in relatively close proximity to one another. The electronic shielding device prevents inadvertent firing of a pyrotechnic device which is adjacent another pyrotechnic device being fired. More particularly, the shielding device prevents the electromagnetic field produced by the transmitting coil from extending to another transmitting or receiving coil associated with another pyrotechnic device in nearby proximity. 
         [0040]    Thus, systems  100 - 600  of the present invention provide remote ignition systems which allow for the reuse of mortar tubes and the reuse of the capacitors and transmitting coils. For instance, an operator of the systems may fire a first pyrotechnic device or a set thereof from one or more mortar tubes  136  and then reload these mortar tubes with additional pyrotechnic devices during a show in order to minimize the number of mortar tubes and associated elements of the system needed in order to fire a given number of pyrotechnic devices. In addition, the present invention substantially reduces the amount of time for setting up a fireworks show due to the elimination of the vast amount of wiring required with prior art devices. The present invention also provides a two-stage firing sequence in addition to the on/off switch for the control and power supply. This two-stage firing sequence, involving activation of the charge button to charge the capacitor and subsequent activation of the fire button to discharge the capacitor, provides a safety mechanism to help ensure that none of the fireworks will be shot while the operator is reloading the mortar tubes with additional fireworks. The wireless ignition of the pyrotechnic device allows for a safe separation of the device from the mortar. 
         [0041]    Preferably, the transmitting coils and associated receiving coils used with pyrotechnic devices which are shot from a mortar tube of a particular diameter will be tuned to a certain frequency or frequency range which is different from analogous coils for pyrotechnics associated with mortar tubes having a different diameter. This would prevent the inadvertent firing of pyrotechnic devices which are not sized to fit with a particular mortar tube. 
         [0042]    The induction system of the present invention has primarily been described with reference to a transmitting induction coil and a receiving induction coil. However, any suitable electrically conductive members may be used as the transmitting and the receiving members of the induction system as long as they are suitably configured for the purpose. In addition, while it is preferred that the transmitting member be an induction coil within a housing as described which may be slid onto the mortar tube, the transmitting induction member may be, for example, simply disposed to one side of the mortar tube in order to produce an electromagnetic field sufficient to create the electrical current within the receiving induction member. In addition, it is noted that the induction system of the present invention may be used without the circuit board and vice versa although the wireless aspect of the induction system facilitates the launching of the pyrotechnic device with the circuit board without concern for separation of a physical connection between an E-match and the circuit board. Various other changes within the scope of the present invention will be evident to one skilled in the art. 
         [0043]    In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
         [0044]    Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.