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.

Description:
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 
   1. Field of Invention 
   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. 
   2. Description of Related Art 
   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. 
     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 . 
   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. 
   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. 
   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 
   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: 
   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. 
   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, 
   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, 
   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 
   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. 
   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: 
   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 
   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 
     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: 
       FIG. 1  shows a vertical cross-sectional view of a known igniter assembly to which the present invention is applied; 
     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 
     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 
   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. 
   The present invention also provides a method of distinguishing between two electroconductive pins provided in an igniter assembly and an electric igniter. 
   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. 
   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. 
   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. 
   The present invention preferably provides the assembly method, wherein the dielectric is an electric insulation cover covering an ignition portion of the electric igniter. 
   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. 
   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. 
   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. 
   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. 
   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   
     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 ). 
   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. 
   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. 
   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. 
   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  (2Ω), and the metallic cover  27 , eyelet  23  and center pin  21   a  become non-resistive conductors. 
   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. 
   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. 
   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   
     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 ). 
   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 . 
   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. 
   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. 
   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. 
   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 . 
   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. 
   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   
   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. 
   
     
       
             
             
           
             
             
             
             
             
           
             
             
             
             
             
           
         
             
                 
               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 
             
             
                 
                 
             
           
        
       
     
   
   
     
       
             
             
           
             
             
             
             
             
           
             
             
             
             
             
           
         
             
                 
               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 
             
             
                 
                 
             
           
        
       
     
   
   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. 
   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   
   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. 
   
     
       
             
             
           
             
             
             
             
             
           
             
             
             
             
             
           
         
             
                 
               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 
             
             
                 
                 
             
           
        
       
     
   
   
     
       
             
             
           
             
             
             
             
             
           
             
             
             
             
             
           
         
             
                 
               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 
             
             
                 
                 
             
           
        
       
     
   
   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. 
   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. 
   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. 
   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.