Patent Abstract:
The present invention is a method of assembling a device employing electric ignition by comprising assembling an igniter assembly in the device, the igniter assembly having an electric igniter provided with a first electroconductive pin and a second electroconductive pin, connected to a power source, the method comprising steps of:
       forming two measurement circuits by using the first electroconductive pin and the second electroconductive pin as a measurement terminal on one end side, respectively, and using another member provided in the igniter assembly as a terminal on the other end side with a pass through a dielectric provided in the igniter assembly,   measuring pure resistances and/or impedances of the two measurement circuits, respectively, by applying a high frequency thereto separately,   distinguishing the first electroconductive pin from the second electroconductive pin from a magnitude relationship (difference) between the measured pure resistance and/or impedance values, and   then, disposing the igniter assembly to the device such that the first electroconductive pin and the second electroconductive pin correspond to predetermined power source electrodes, respectively.

Full Description:
[0001]    This nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2006-342118 filed in Japan on 20 Dec. 2006 and under 35 U.S.C. § 119(e) on U.S. Provisional Application No. 60/884,562 filed on 11 Jan. 2007, which are incorporated by reference. 
     
    
     BACKGROUND OF INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to an assembly method for a device that employs electric ignition, such as an air bag device, and a method of distinguishing between two electroconductive pins provided in an electric igniter. 
         [0004]    2. Description of Related Art 
         [0005]    In an electric igniter having two electroconductive pins (a center pin and an eyelet pin) for electrifying a heating wire (a body that generates heat through electric resistance) or an igniter assembly using the electric igniter, positive and negative electrodes are usually connected to predetermined electroconductive pins, and when a positive or negative electrode is connected to the wrong electroconductive pin, a defective product is obtained. 
         [0006]      FIG. 1  illustrates the structure of a known igniter assembly  10 . An electric igniter  20  is coupled integrally to a metallic igniter collar  30  by a resin  31 . 
         [0007]    In the electric igniter  20 , a center pin  21   a  is insulated from a metallic header (eyelet)  23  by a glass member  22  and connected to a heat-generating body (bridge wire)  24 . An eyelet pin  21   b  is connected to the eyelet  23  and connected to the heat-generating body (bridge wire)  24  via the eyelet  23 . An ignition agent  26  is charged into a tubular spacer  25  so as to press against the heat-generating body (bridge wire)  24 . The eyelet  23  and the tubular spacer  25  are covered from the outside by a metallic cover  27 , together forming an ignition portion of the electric igniter  20 . Further, the metallic cover  27  of the ignition portion is covered by a resin cover  28  having an electric insulation property. A space  29  serves as a space for inserting a connector plug having a lead wire. 
         [0008]    As shown in  FIG. 1 , the igniter assembly  10  has a structure in which a resin  31  is molded between the igniter  20  and igniter collar  30 , and therefore it is impossible to distinguish between the center pin  21   a  and the eyelet pin  21   b  from the outer form thereof. 
         [0009]    Conventionally, the center pin  21   a  is distinguished from the eyelet pin  21   b  by means of X-ray projection, but X-ray projectors and X-ray lamps are both expensive, leading to an increase in maintenance costs that is reflected in the manufacturing costs of the igniter JP-A No. 2001-165600 and JP-A No. 2006-35970 may be related arts of the present invention. 
       SUMMARY OF INVENTION 
       [0010]    One of the inventions provides a method of assembling a device employing electric ignition by comprising assembling an igniter assembly in the device, the igniter assembly having an electric igniter provided with a first electroconductive pin and a second electroconductive pin, connected to a power source, the method comprising steps of: 
         [0011]    forming two measurement circuits by using the first electroconductive pin and the second electroconductive pin as a measurement terminal on one end side, respectively, and using another member provided in the igniter assembly as a terminal on the other end side with a pass through a dielectric provided in the igniter assembly, 
         [0012]    measuring pure resistances and/or impedances of the two measurement circuits, respectively, by applying a high frequency thereto separately, 
         [0013]    distinguishing the first electroconductive pin from the second electroconductive pin from a magnitude relationship (difference) between the measured pure resistance and/or impedance values, and 
         [0014]    then, disposing the igniter assembly to the device such that the first electroconductive pin and the second electroconductive pin correspond to predetermined power source electrodes, respectively. 
         [0015]    In other words, it is an assembly method for a device employing electric ignition, including a step of attaching an igniter assembly to the device, 
         [0016]    wherein the igniter assembly has an electric igniter having a first electroconductive pin and a second electroconductive pin for connecting the electric igniter to a power source, 
         [0017]    two measurement circuits passing through a dielectric provided in the igniter assembly are formed such that the first electroconductive pin or the second electroconductive pin serves as a measurement terminal on one end side and another member provided in the igniter assembly serves as a terminal on another end side, and 
         [0018]    a high frequency is introduced separately into the two measurement circuits to measure pure resistances and/or impedances, and the first electroconductive pin is distinguished from the second electroconductive pin from a magnitude relationship (difference) between the measured pure resistance and/or impedance values, whereupon the igniter assembly is attached to the device such that the first electroconductive pin and the second electroconductive pin correspond to predetermined power source electrodes. 
         [0019]    Another one of the inventions provides a method of distinguishing between a first electroconductive pin and a second electroconductive pin, provided in an electric igniter in an igniter assembly including the electric igniter, comprising steps of: 
         [0020]    forming two measurement circuits passing through a dielectric, provided in the igniter assembly, such that the first electroconductive pin and the second electroconductive pin serves as a measurement terminal on one end side and another member provided in the igniter assembly serves as a terminal on another end side; and 
         [0021]    measuring pure resistances and/or impedances of the two measurement circuits, respectively, by applying a high frequency thereto separately, and distinguishing between the first electroconductive pin and the second electroconductive pin from a magnitude relationship (difference) between the measured pure resistance and/or impedance values. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein: 
           [0023]      FIG. 1  shows a vertical cross-sectional view of a known igniter assembly to which the present invention is applied; 
           [0024]    In  FIG. 2 , (a) shows a sectional view of an igniter assembly for illustrating an assembly method and a distinguishing method of the present inventions and a schematic view of high-frequency resistance measurement circuits including the igniter assembly, and (b) shows an equivalent circuit diagram of the igniter assembly shown in (a) in high-frequency resistance measurement; and 
           [0025]    In  FIG. 3 , (a) shows a sectional view of a gas generator having an igniter assembly for illustrating an assembly method and a distinguishing method of the present invention, and a schematic view of high-frequency resistance measurement circuits including the igniter assembly, and (b) shows an equivalent circuit diagram of the gas generator shown in (a) in high-frequency resistance measurement. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0026]    The present invention provides an assembly method for a device that employs electric ignition, such as an air bag device, with which it is possible to distinguish between two electroconductive pins provided in an igniter assembly and an electric igniter, thereby improving the reliability of the device. 
         [0027]    The present invention also provides a method of distinguishing between two electroconductive pins provided in an igniter assembly and an electric igniter. 
         [0028]    By employing a commercially available high-frequency resistance measuring device, the sign, positive or negative, of the two electroconductive pins can be confirmed easily. Hence, in comparison with a conventional method employing an X-ray projector, manufacturing costs can be reduced. 
         [0029]    Various devices, such as an occupant-protecting air bag device (a gas generator for an air bag) or a seatbelt pretensioner installed in a vehicle such as an automobile, may be cited as examples of a device employing electric ignition. 
         [0030]    An igniter assembly in which a collar member is incorporated into a lower portion (including a part of the electroconductive pins) of an electric igniter via a resin, and a gas generator in which a cap member is fixed to the collar member of the igniter assembly and a gas generating agent is charged between the electric igniter and the cap, or in other words a gas generator having an igniter assembly, may be cited as examples of an igniter assembly. 
         [0031]    The present invention preferably provides the assembly method, wherein the dielectric is an electric insulation cover covering an ignition portion of the electric igniter. 
         [0032]    The present invention preferably provides the assembly method, wherein the dielectric is a resin which integrally couples a metallic igniter collar to the electric igniter. 
         [0033]    By employing a commercially available high-frequency resistance measuring device, the sign, positive or negative, of the two electroconductive pins can be confirmed easily. Hence, in comparison with a conventional method employing an X-ray projector, manufacturing costs can be reduced. 
         [0034]    The present invention preferably provides the method of distinguishing between a first electroconductive pin and a second electroconductive pin, wherein the dielectric is an electric insulation cover covering an ignition portion of the electric igniter. 
         [0035]    The present invention preferably provides the method of distinguishing between a first electroconductive pin and a second electroconductive pin, wherein the dielectric is a resin which integrally couples a metallic igniter collar to the electric igniter. 
         [0036]    By applying the distinguishing method of the present invention, it is possible to distinguish between two electroconductive pins provided in an igniter assembly easily and at a lower cost than a conventional method. Therefore, when assembling an automobile safety device such as an air bag device (a gas generator for an air bag) or a seatbelt pretensioner, the respective electroconductive pins can be attached appropriately to the corresponding ignition power source electrodes, without confusing the two electroconductive pins, as a result of which the reliability of the device is improved. 
       EMBODIMENT OF INVENTION 
     (1) Assembly Method or Distinguishing Method in FIG.  2   
       [0037]      FIG. 2(   a ) is a sectional view of an igniter assembly for illustrating an assembly method and a distinguishing method of the present invention, and a schematic view of high-frequency resistance measurement circuits including the igniter assembly.  FIG. 2(   b ) is an equivalent circuit diagram of high-frequency resistance measurement performed on the igniter assembly shown in  FIG. 2(   a ). 
         [0038]    The igniter assembly  10  is identical to the igniter assembly shown in  FIG. 1 , in which an ignition portion (the metallic cover  27  and the interior thereof) of the electric igniter  20  is covered by the resin cover  28  (electric insulation cover), which has an electric insulation property. 
         [0039]    In high-frequency resistance measurement of the igniter assembly  10 , a first measurement circuit having the center pin (first electroconductive pin)  21   a  as a terminal on one end side and the resin cover  28  as a terminal on the other end side and a second measurement circuit having the eyelet pin (second electroconductive pin)  21   b  as a terminal on one end side and the resin cover  28  as a terminal on the other end side are formed. In these circuits, the resin cover  28  and the glass member  22  serve as dielectrics. 
         [0040]    A high-frequency resistance measuring device  40  is disposed on the first measurement circuit and second measurement circuit. A device described in Examples may be used as the high-frequency resistance measuring device. 
         [0041]    When a high frequency is introduced into the first measurement circuit (between the resin cover  28  and the center pin  21   a ) by the high-frequency resistance measuring device  40 , the resin cover (dielectric)  28  becomes a capacitor C 0 , the glass member  22  becomes a capacitor C 1 , the bridge wire  24  becomes a resistor R 1  ( 2 Q), and the metallic cover  27 , eyelet  23  and center pin  21   a  become non-resistive conductors. 
         [0042]    Meanwhile, when a high frequency is introduced into the second measurement circuit (between the resin cover  28  and the eyelet pin  21   b ) by the high-frequency resistance measuring device  40 , the resin cover (dielectric)  28  becomes a capacitor C 0 , and the metallic cover  27 , eyelet  23  and eyelet pin  21   b  become non-resistive conductors. 
         [0043]    Hence, the first measurement circuit and second measurement circuit differ in circuit configuration and the path along which the high frequency flows, and therefore also differ in high-frequency resistance (pure resistance and/or impedance). Therefore, when an appropriate high frequency is selected and measurement is performed at this high frequency, a magnitude relationship occurs between the measured high-frequency resistance values. Accordingly, by measuring the high-frequency resistance (pure resistance and/or impedance) at different high frequencies in advance with respect to an igniter assembly (measurement reference product) having a specific structure and serving as a measurement subject, confirming the frequency of a high frequency at which a magnitude relationship occurs between the high-frequency resistance values measured in relation to the first measurement circuit and second measurement circuit, and using this high frequency to measure the high-frequency resistances (pure resistances and/or impedances) of the first measurement circuit and second measurement circuit, it is possible to distinguish between the center pin (first electroconductive pin) and eyelet pin (second electroconductive pin) easily from the magnitude relationship between the high-frequency resistance values of the first measurement circuit and second measurement circuit. 
         [0044]    After distinguishing between the two electroconductive pins (the center pin and eyelet pin) of the igniter assembly in this manner, the igniter assembly is incorporated into a known gas generator (for example, a gas generator used in a seatbelt pretensioner, disclosed in JP-A No. 2005-225274, or an air bag gas generator incorporated with an igniter assembly formed by integrating an igniter and a metallic collar by interposing resin therebetween, disclosed in FIGS. 1, 6 and 8 of JP-A No. 2001-16500), whereupon the gas generator is incorporated into an automobile safety device (for example, an air bag device or a seatbelt pretensioner) and installed in a vehicle. When an ignition power source (battery) is connected to the two electroconductive pins of the igniter assembly at this time, confusion between the positive and negative electrodes is eliminated. As a result, the reliability of the finally assembled automobile safety device is improved. 
       (2) Assembly Method and Distinguishing Method in FIG.  3   
       [0045]      FIG. 3(   a ) is a sectional view of an igniter assembly for illustrating an assembly method and a distinguishing method of the present invention, and a schematic view of high-frequency resistance measurement circuits including the igniter assembly.  FIG. 3(   b ) is an equivalent circuit diagram of high-frequency resistance measurement performed on the igniter assembly shown in  FIG. 3(   a ). 
         [0046]    In  FIG. 3(   a ), an opening portion  37  of a metallic cap  36  is fixed to the metallic collar  30  of the igniter assembly  10  shown in  FIG. 1 , and a molded body of gas generating agent  35  is charged into an interior space of the metallic cap  36 . 
         [0047]    In high-frequency resistance measurement of a gas generator  50 , a first measurement circuit having the center pin  21   a  as a terminal on one end side and the metallic cap  36  as a terminal on the other end side and a second measurement circuit having the eyelet pin  21   b  as a terminal on one end side and the metallic cap  36  as a terminal on the other end side are formed. In these circuits, the resin  31  and the glass member  22  serve as dielectrics. 
         [0048]    When a high frequency is introduced into the first measurement circuit (between the metallic cap  36  and the center pin  21   a ) by the high-frequency resistance measuring device  40 , the glass member  22  becomes a capacitor C 1 , the resin (the resin between the center pin  21   a  and the metallic collar  30 )  31  becomes a capacitor C 3 , the bridge wire  24  becomes a resistor R 1  (2Ω), and the metallic cap  36 , metallic collar  30  and center pin  21   a  become non-resistive conductors. 
         [0049]    Meanwhile, when a high frequency is introduced into the second measurement circuit (between the metallic cap  36  and the eyelet pin  21   b ) by the high-frequency resistance measuring device  40 , the glass member  22  becomes a capacitor C 1 , the resin (the resin between the eyelet pin  21   b  and the metallic collar  30 )  31  becomes a capacitor C 2 , the bridge wire  24  becomes a resistor R 1  (2Ω), and the metallic cap  36 , metallic collar  30  and eyelet pin  21   b  become non-resistive conductors. 
         [0050]    Hence, the first measurement circuit and second measurement circuit differ in the path along which the high frequency flows (in the first measurement circuit, the high frequency flows along the path of the capacitor C 3 , and in the second measurement circuit, the high frequency flows along the path of the capacitor C 2 ), and therefore also differ in high-frequency resistance (pure resistance and/or impedance). Therefore, when an appropriate high frequency is selected and measurement is performed at this high frequency, a magnitude relationship occurs between the measured high-frequency resistance values. The reason for this is that in the gas generator shown in  FIG. 3(   a ), the center pin  21   a  and the eyelet pin  21   b  bend in the same direction in respective parts thereof that are covered by the resin  31 , and in these resin  31  parts, the distance between the center pin  21   a  and metallic collar  30  differs from the distance between the eyelet pin  21   b  and metallic collar  30 . Hence, the capacitance of the capacitor C 3  differs from the capacitance of the capacitor C 2 . 
         [0051]    Accordingly, by measuring the high-frequency resistance (pure resistance and/or impedance) at different high frequencies in advance with respect to an igniter assembly (measurement reference product) having a specific structure and serving as a measurement subject, confirming the frequency of a high frequency at which a magnitude relationship occurs between the high-frequency resistance values measured in relation to the first measurement circuit and second measurement circuit, and using this high frequency to measure the high-frequency resistances (pure resistances and/or impedances) of the first measurement circuit and second measurement circuit, it is possible to distinguish between the center pin (first electroconductive pin) and eyelet pin (second electroconductive pin) easily from the magnitude relationship between the high-frequency resistance values of the first measurement circuit and second measurement circuit. 
         [0052]    After distinguishing between the two electroconductive pins (the center pin and eyelet pin) of the gas generator in this manner, the gas generator is incorporated into a known automobile safety device (for example, a pretensioner of a seatbelt retractor, disclosed in JP-A No. 2003-267186), whereupon the gas generator is incorporated into an air bag device (for example, a seatbelt pretensioner) and then installed in a vehicle. When an ignition power source (battery) is connected to the two electroconductive pins of the igniter assembly at this time, confusion between the positive and negative electrodes is eliminated. As a result, the reliability of the finally assembled automobile safety device is improved. 
       EXAMPLES 
     Example 1 
     Igniter Assembly of FIG.  2   
       [0053]    The two measurement circuits (first measurement circuit and second measurement circuit) shown in  FIGS. 2(   a ) and  2 ( b ) were prepared, whereupon the pure resistance value (Ω) and impedance (Ω) were measured while varying the frequency, as shown in Tables 1 and 2. A “Network Analyzer, Model: 8753ES, Frequency Range: 30 kHz to 3 GHz”, manufactured by Agilent Technologies Inc., was used as the high-frequency resistance measuring device. 
         [0000]    
       
         
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Pure Resistance(Ω) 
               
             
          
           
               
                   
                   
                 First 
                 Second 
                   
               
               
                   
                 Frequency 
                 measurement 
                 measurement 
               
               
                   
                 (MHz) 
                 circuit 
                 circuit 
                 Difference 
               
               
                   
                   
               
             
          
           
               
                   
                 3 
                 202.500 
                 233.500 
                 −31.000 
               
               
                   
                 4 
                 156.000 
                 173.500 
                 −17.500 
               
               
                   
                 5 
                 116.000 
                 134.130 
                 −18.130 
               
               
                   
                 6 
                 89.250 
                 106.630 
                 −17.380 
               
               
                   
                 7 
                 73.130 
                 86.500 
                 −13.370 
               
               
                   
                 8 
                 57.880 
                 70.750 
                 −12.870 
               
               
                   
                 9 
                 45.690 
                 58.190 
                 −12.500 
               
               
                   
                 10 
                 37.810 
                 47.940 
                 −10.130 
               
               
                   
                 15 
                 8.880 
                 16.690 
                 −7.810 
               
               
                   
                 20 
                 13.219 
                 16.906 
                 −3.687 
               
               
                   
                 30 
                 8.188 
                 9.313 
                 −1.125 
               
               
                   
                 40 
                 12.000 
                 11.859 
                 0.141 
               
               
                   
                 50 
                 9.578 
                 8.797 
                 0.781 
               
               
                   
                 60 
                 5.570 
                 4.297 
                 1.273 
               
               
                   
                 70 
                 5.336 
                 4.313 
                 1.023 
               
               
                   
                 80 
                 6.875 
                 6.953 
                 −0.078 
               
               
                   
                 90 
                 7.938 
                 8.914 
                 −0.976 
               
               
                   
                 100 
                 7.031 
                 6.340 
                 0.691 
               
               
                   
                 150 
                 4.141 
                 2.277 
                 1.864 
               
               
                   
                 200 
                 5.466 
                 3.151 
                 2.315 
               
               
                   
                 300 
                 77.711 
                 75.297 
                 2.414 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
             
             
               
                   
                   
               
               
                   
                 Impedance(Ω) 
               
             
          
           
               
                   
                   
                 First 
                 Second 
                   
               
               
                   
                 Frequency 
                 measurement 
                 measurement 
               
               
                   
                 (MHz) 
                 circuit 
                 circuit 
                 Difference 
               
               
                   
                   
               
             
          
           
               
                   
                 3 
                 5435.074 
                 5224.221 
                 210.853 
               
               
                   
                 4 
                 4108.962 
                 3987.177 
                 121.785 
               
               
                   
                 5 
                 3296.841 
                 3223.692 
                 73.149 
               
               
                   
                 6 
                 2757.245 
                 2705.502 
                 51.743 
               
               
                   
                 7 
                 2365.631 
                 2334.103 
                 31.528 
               
               
                   
                 8 
                 2074.208 
                 2049.721 
                 24.487 
               
               
                   
                 9 
                 1844.666 
                 1827.127 
                 17.539 
               
               
                   
                 10 
                 1662.430 
                 1648.097 
                 14.333 
               
               
                   
                 15 
                 1110.636 
                 1106.926 
                 3.710 
               
               
                   
                 20 
                 826.046 
                 825.113 
                 0.933 
               
               
                   
                 30 
                 543.622 
                 544.490 
                 −0.868 
               
               
                   
                 40 
                 399.520 
                 400.176 
                 −0.656 
               
               
                   
                 50 
                 312.777 
                 312.924 
                 −0.147 
               
               
                   
                 60 
                 254.551 
                 254.406 
                 0.145 
               
               
                   
                 70 
                 209.048 
                 208.295 
                 0.753 
               
               
                   
                 80 
                 170.549 
                 168.573 
                 1.976 
               
               
                   
                 90 
                 136.701 
                 133.059 
                 3.642 
               
               
                   
                 100 
                 127.624 
                 126.030 
                 1.594 
               
               
                   
                 150 
                 48.491 
                 47.547 
                 0.944 
               
               
                   
                 200 
                 14.943 
                 15.883 
                 −0.940 
               
               
                   
                 300 
                 193.913 
                 198.959 
                 −5.046 
               
               
                   
                   
               
             
          
         
       
     
         [0054]    As is evident from Tables 1 and 2, a magnitude relationship occurred clearly in both the pure resistance and the impedance between the first measurement circuit (between the resin cover  28  and the center pin  21   a ) and the second measurement circuit (between the resin cover  28  and the eyelet pin  21   b ) at each frequency. It is therefore possible to distinguish between the two electroconductive pins of the igniter assembly easily. Hence, confusion does not occur between the positive and negative electrodes of the ignition power source that is connected to the two electroconductive pins when incorporating the igniter assembly in a device, and the device can be assembled reliably and easily. 
         [0055]    As shown in Tables 1 and 2, the measurement values of the pure resistance and impedance of the igniter assembly vary according to the frequency of the high frequency, and therefore, by selecting a high frequency at which the magnitude relationship between the respective measurement values of the first measurement circuit and second measurement circuit is comparatively large, and performing the measurement at this frequency, it is possible to distinguish between the center pin and the eyelet pin without influence from measurement errors. 
       Example 2 
     Gas Generator of FIG.  3   
       [0056]    The two measurement circuits (first measurement circuit and second measurement circuit) shown in  FIGS. 3(   a ) and  3 ( b ) were prepared, whereupon the pure resistance value (Ω) and impedance (Ω) were measured while varying the frequency, as shown in Tables 3 and 4. A “Vector Network Analyzer, Model: ZVRE, Frequency Range: 10 kHz to 4 GHz”, manufactured by ROHDE &amp; SCHWARZ, Inc. was used as the high-frequency resistance measuring device. 
         [0000]    
       
         
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 3 
               
             
             
               
                   
                   
               
               
                   
                 Pure Resistance(Ω) 
               
             
          
           
               
                   
                   
                 First 
                 Second 
                   
               
               
                   
                 Frequency 
                 measurement 
                 measurement 
               
               
                   
                 (MHz) 
                 circuit 
                 circuit 
                 Difference 
               
               
                   
                   
               
             
          
           
               
                   
                 10 
                 188.560 
                 185.810 
                 2.750 
               
               
                   
                 15 
                 111.750 
                 106.750 
                 5.000 
               
               
                   
                 20 
                 81.969 
                 79.437 
                 2.532 
               
               
                   
                 30 
                 48.156 
                 47.031 
                 1.125 
               
               
                   
                 40 
                 36.625 
                 35.516 
                 1.109 
               
               
                   
                 50 
                 28.578 
                 27.156 
                 1.422 
               
               
                   
                 60 
                 22.906 
                 21.109 
                 1.797 
               
               
                   
                 70 
                 19.703 
                 18.383 
                 1.320 
               
               
                   
                 80 
                 17.102 
                 16.086 
                 1.016 
               
               
                   
                 90 
                 15.148 
                 14.273 
                 0.875 
               
               
                   
                 100 
                 14.000 
                 13.109 
                 0.891 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 4 
               
             
             
               
                   
                   
               
               
                   
                 Impedance(Ω) 
               
             
          
           
               
                   
                   
                 First 
                 Second 
                   
               
               
                   
                 Frequency 
                 measurement 
                 measurement 
               
               
                   
                 (MHz) 
                 circuit 
                 circuit 
                 Difference 
               
               
                   
                   
               
             
          
           
               
                   
                 10 
                 1633.295 
                 1601.979 
                 31.316 
               
               
                   
                 15 
                 1091.104 
                 1063.054 
                 28.050 
               
               
                   
                 20 
                 828.691 
                 809.123 
                 19.568 
               
               
                   
                 30 
                 560.857 
                 549.356 
                 11.501 
               
               
                   
                 40 
                 421.799 
                 411.310 
                 10.489 
               
               
                   
                 50 
                 335.653 
                 327.107 
                 8.546 
               
               
                   
                 60 
                 276.437 
                 270.199 
                 6.238 
               
               
                   
                 70 
                 232.448 
                 227.033 
                 5.445 
               
               
                   
                 80 
                 198.717 
                 193.886 
                 4.831 
               
               
                   
                 90 
                 171.725 
                 167.378 
                 4.347 
               
               
                   
                 100 
                 149.488 
                 145.612 
                 3.876 
               
               
                   
                   
               
             
          
         
       
     
         [0057]    As is evident from Tables 3 and 4, a magnitude relationship occurred clearly in both the pure resistance and the impedance between the first measurement circuit (between the metallic cap  36  and the center pin  21   a ) and the second measurement circuit (between the metallic cap  36  and the eyelet pin  21   b ) at each frequency. It is therefore possible to distinguish between the two electroconductive pins of the igniter assembly provided in the gas generator easily. Hence, confusion does not occur between the positive and negative electrodes of the ignition power source that is connected to the two electroconductive pins when incorporating the igniter assembly in a device, and the device can be assembled reliably and easily. 
         [0058]    As shown in Tables 3 and 4, the measurement values of the pure resistance and impedance of the igniter assembly vary according to the frequency of the high frequency, and therefore, by selecting a high frequency at which the magnitude relationship between the respective measurement values of the first measurement circuit and second measurement circuit is comparatively large and performing the measurement at this high frequency, it is possible to distinguish between the center pin and the eyelet pin without influence from measurement errors. 
         [0059]    As is evident from the high-frequency resistance measurement results shown in Tables 1 to 4, it is possible to distinguish between the two electroconductive pins of an igniter assembly (including a gas generator having an igniter assembly) by measuring either one of the pure resistance and the impedance. It is also possible to distinguish between the two electroconductive pins by measuring both the pure resistance and the impedance. 
         [0060]    The invention thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scoped of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Technology Classification (CPC): 5