Igniter and method of manufacturing an igniter for an inflator

Abstract

A pyrotechnical igniter (100) for an inflator of a vehicle safety system comprises at least two contact pins (102) physically separated from each other by an electrically insulating compound and a bridge wire (110) connected to both contact pins (102) in an electrically conducting manner. A fastening portion (112) in which the bridge wire (110) is welded to the contact pins (102) is provided at each of the contact pins (102).

Claims

1. A pyrotechnical igniter (100) for an inflator of a vehicle safety system comprising: at least two contact pins (102) physically separated from each other by an electrically insulating compound and a bridge wire (110) connected to both contact pins (102) in an electrically conducting manner, wherein fastening portions (112) at opposite ends of the bridge wire (110) comprise weld joints in which the opposite ends of the bridge wire are welded to end faces (108) of the contact pins (102), and wherein in a top view a minimum distance (d) between a rim of the fastening portion (112) and the insulating compound between the contact pins (102) is 0.01 to 0.5 mm, the minimum distance (d) being configured to be the minimum distance from the insulating compound between the contact pins sufficient to prevent the insulating compound between the contact pins from polluting the weld joints.

2. The pyrotechnical igniter according to claim 1, further comprising at least two contact pins (102) physically separated from each other by an electrically insulating compound, each contact pin (102) being provided with a chlorine-free gold coating (126).

3. A method of manufacturing the pyrotechnical igniter according to claim 2, comprising steps of: introducing chlorine traps into a purifying solution and applying the gold layer in a galvanic process.

4. The pyrotechnical igniter according to claim 1, wherein at least one of a pole body of the igniter and a cap outwardly closing off the igniter are made of plastic material having a substantially linear or cross-linked chain structure.

5. The pyrotechnical igniter according to claim 1, wherein at least one of a pole body (104; 204) of the igniter (100; 200) and a cap (122; 222) outwardly closing off the igniter (100; 200) are made of thermosetting plastic.

6. The pyrotechnical igniter according to claim 1, further comprising at least two contact pins (102) and a bridge wire (110) connected to both contact pins (102) in an electrically conducting manner, wherein the bridge wire comprises a nickel alloy with chromium at percentages of 11 to 24% and molybdenum at percentages of 12.5 to 17% and the specific resistance of the bridge wire ranges from 0.25 to 3 Ωmm.sup.2/m.

7. The pyrotechnical igniter according to claim 1, further comprising a pole body (104) including two contact pins (102) and a cap (122) outwardly closing off the igniter (100), wherein a seal (148) of a sealing compound is provided between at least one of the pole body (104) and the cap (122) and between the contact pins (102) and the pole body (104).

8. The pyrotechnical igniter according to claim 1, further comprising a pole body (104) including at least two contact pins (102) and a cap (122) outwardly closing off the igniter (100), the length (h) of the cap (122) in the longitudinal direction (A) of the igniter (100) being 7 to 15 mm.

9. The pyrotechnical igniter according to claim 1, further comprising a pole body (104) including at least two contact pins (102) and a cap (122) outwardly closing off the igniter (100), wherein the cap (122) includes two different plastic components.

10. A method of manufacturing the pyrotechnical igniter especially according to claim 9, comprising the step of fabricating the cap (122) by injection molding, wherein both plastic components are introduced to an injection mold in the same processing step.

11. The pyrotechnical igniter according to claim 1, comprising a pole body (104) including at least two contact pins (102) and a cap (122) outwardly closing off the igniter (100) and having a predetermined weakening zone (152) in which upon activation of the igniter (100) the material of the cap (122) yields under the internal pressure in the igniter (100), wherein the weakening zone (152) is arranged in a lateral circumferential wall (150) of the cap (122).

12. The pyrotechnical igniter according to claim 6, wherein the bridge wire further includes at least one of iron at a percentage up to 7% and tungsten at a percentage up to 4.5%.

13. The pyrotechnical igniter according to claim 1, wherein in the top view the minimum distance (d) between the rim of the fastening portion (112) and the insulating compound is 0.01 to 0.2 mm.

14. The pyrotechnic igniter according to claim 8, wherein the length (h) of the cap (122) in the longitudinal direction (A) of the igniter (100) is 8 to 12 mm.

15. A pyrotechnical igniter for an inflator of a vehicle safety system comprising: at least two axially extending contact pins physically separated from each other by an electrically insulating compound, each contact pin including an end face delimited by a circumferential rim; and a bridge wire having fastening portions formed by welded connection with the end face of each contact pin, the welded connections comprising weld joints electrically connecting the bridge wire to each contact pin, wherein a minimum radial distance between a rim of the fastening portions and the insulating compound is maintained, the minimum distance being configured to be the minimum distance from the insulating compound separating the pins sufficient to prevent the insulating compound between the pins and adjacent the rim from polluting the weld joints.

16. The pyrotechnical igniter according to claim 15, wherein the minimum radial distance is 0.01 to 0.5 mm.

17. The pyrotechnical igniter according to claim 15, wherein the bridge wire is directly connected to two of the contact pins and is free of connection to igniter structure between the two contact pins.

18. The pyrotechnical igniter according to claim 1, wherein the bridge wire is directly connected to two of the contact pins and is free of connection to igniter structure between the two contact pins.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further preferred embodiments of the invention constitute the subject matter of the respective subclaims. Hereinafter the invention will be described in detail by way of an embodiment with respect to the enclosed drawing, in which:

(2) FIG. 1 shows a schematic sectional view of an igniter according to the invention;

(3) FIG. 2 shows a schematic top view onto the end face of the pole body of the igniter of FIG. 1;

(4) FIG. 3 shows a schematic sectional view of an igniter of the invention according to another embodiment;

(5) FIG. 4 shows a schematic sectional view of an igniter of the invention according to another embodiment;

(6) FIG. 5 shows a schematic sectional view of an igniter of the invention according to another embodiment;

(7) FIG. 6 shows a schematic sectional view of an igniter of the invention according to another embodiment;

(8) FIG. 7 shows a schematic sectional view of an igniter of the invention according to another embodiment;

(9) FIG. 8 shows a schematic sectional view of an igniter of the invention according to another embodiment;

(10) FIG. 9 shows a schematic view of a cap of an igniter of the invention;

(11) FIG. 10 shows a schematic sectional view of an igniter of the Invention according to another embodiment;

(12) FIG. 11 shows a schematic view of a cap of an igniter according to the invention; and

(13) FIG. 12 shows a schematic sectional view of the cap of FIG. 11.

DESCRIPTION

(14) FIG. 1 illustrates an igniter 100. The igniter 100 has two electric contact pins 102 which in portions extend in parallel to each other. The two contact pins 102 are embedded in an electrically insulating compound at a distance from each other. The insulating compound is part of a pole body 104 forming the lower portion of the igniter 100. In this case the insulating compound and the pole body 104 are integrally made of an appropriate plastic material.

(15) The upper end of the pole body 104 is enclosed by a cap 122 connected to the pole body 104. The interior of the cap 122 defines an ignition chamber 124 in which an igniting mixture 116 is accommodated. The igniting mixture 116 is subdivided in this example into a primary ignition charge 118 and a secondary ignition charge 120, wherein also a further added tertiary ignition charge is imaginable.

(16) At its free rim the cap 122 includes a flat end face 128 facing a flat shoulder surface 130 of the pole body 104. A cylindrical inner circumferential wall 132 of the cap 122 surrounds the upper end of the pole body 104. The closed end of the cap 122 forms a Hat end wall 134. Between the end wall 134 and the radially outwardly projecting rim of the end face 128 the cap 122 has a cylindrical circumferential wall 136. The cap 122 likewise consists of plastic material.

(17) In a first embodiment both contact pins 102 protrude about 0.1 to 1 mm from a flat end face 106 of the insulating compound and of the pole body 104. Also the end feces 108 of the contact pins 102 projecting from the insulating compound are substantially flat.

(18) A bridge wire 110 which is welded at one end in a first fastening portion 112 to the end face 108 at the first contact pin 102 and at its second end in a second fastening portion 112 to the end face 108 of the second contact pin 102 extends between the contact pins 102, more exactly speaking between the end faces 108 of the contact pins 102. In this way, the bridge wire 110 is connected to both contact pins 102 in an electrically conducting manner.

(19) The dimensions of the fastening portion 112 correspond to those of the welded joint between the bridge wire 110 and the contact pin 102.

(20) The position of the fastening portion 112 is selected so that a minimum distance d between a rim of the fastening portion and the insulating compound of the pole body 104, in this case the distance between the rim of the fastening portion 112 and a rim 114 of the end face 108 of the contact pin 102, is between 0.01 and 0.5 mm and, respectively, between 0.01 and 0.2 mm.

(21) In the shown example the bridge wire 110 is a CrNi wire.

(22) The bridge wire 110 has a specific resistance ranging from 0.30 to 0.32 Ωmm.sup.2/m.

(23) In this example the bridge wire 110 has a diameter of from 20.8 to 21.5 μm.

(24) The end face 106 of the pole body 104, the upper ends of the contact pins 102 including the end faces 108 and also the bridge wire 110 including the fastening portions 112 are in contact with the igniting mixture 116. In this example the primary ignition charge 118 is in direct contact with the end face 106 of the pole body 104 and completely surrounds the end faces 108 of the contact pins 102 and the bridge wire 110.

(25) Usually the primary ignition charge 118 is formed of a mixture of zirconium and potassium perchlorate. The secondary ignition charge 120 and an optionally further added tertiary ignition charge, respectively, can be made of titanium hydride mixed with potassium perchlorate.

(26) In general, the igniting mixture may contain a composition of an oxidant and an inorganic and/or organic fuel.

(27) The oxidant preferably is at least a perchlorate and/or at least a chlorate.

(28) The inorganic fuel used can be at least a substance out of the group of metals, metal alloys and metal hydrides.

(29) Preferably the inorganic fuel is selected from the group consisting of magnesium, aluminum, magnesium aluminum alloys, titanium, zirconium, titanium aluminum alloys, LiN, MgH.sub.2, LiAlH.sub.4, TiH, tungsten, zirconium tungsten alloys and the mixtures thereof.

(30) The organic fuel used can be guanidine compounds, tetrazole compounds, triazole compounds, urea compounds, nitre compounds, nitramine compounds, dicarboxyllc acids, polymer compounds as well as the salts and mixtures thereof.

(31) The fuel can consist of the inorganic fuel, the organic fuel and a mixture of the inorganic and the organic fuel.

(32) Alternatively in the igniting mixture also explosives such as potassium dinitrobenzofuroxan can be used without further addition of oxidants.

(33) Such igniting mixture has turned out to be advantageous mainly for igniters the pole body and cap of which are made of plastic material.

(34) In accordance with another embodiment both contact pins 102 are coated with a chlorine-free gold coating 140 (indicated in hatched lines in FIG. 3) at least at their free ends protruding from the pole body 104 of the igniter 100. In the shown embodiment both contact pins 102 are completely coated with the gold coating 140.

(35) However, it is also possible not to coat the portions of the contact pins 102 located inside the pole body 104 and the ignition chamber 124.

(36) According to a first example, a flash gold layer having a thickness of less than 0.25 μm, preferably of less than 0.13 μm, is applied to a body 142 of each contact pin 102. The thickness preferably amounts to 0.05 to 0.08 μm.

(37) A hard gold layer having a layer thickness of more than 0.5 μm is applied to said flash gold layer.

(38) Both layers were deposited current-less in a chemical method.

(39) As in the first example, a flash gold layer is applied to the body 142 of the contact pins 102. On said flash gold layer a nickel layer having a thickness of 1.0 to 2.0 μm was deposited and on said nickel layer a hard gold layer having a thickness of at least 0.7 μm, preferably of 0.76 to 0.90 μm was deposited.

(40) In a first variant the nickel layer is electrodeposlted as sulfamate nickel layer.

(41) In a second variant the nickel layer is produced in a current-less chemical deposition.

(42) The gold layer is deposited in a galvanic process, with chlorine traps being contained in a purifying solution which is used in a purifying step utilized prior to deposition. These chlorine traps drastically reduce the number of chloride tons included below the gold layer so that a substantially chlorine-free gold layer is resulting.

(43) In this example a palladium layer having a thickness of about 70 nm is applied to the body 142 of the contact pins 102 and in turn a gold layer having a thickness of about 5 nm is applied to said palladium layer.

(44) In a further embodiment both the pole body 104 and the cap 122 consist of a plastic material having a substantially linear chain structure. However, also cross-linked chain structures, for instance cross-linked polyphenylene sulfate, can be used.

(45) In a first variant the plastic is linear polyphenylene sulfate.

(46) In a second variant the plastic is glass-fiber reinforced polyamide, for instance having a glass fiber content of 50%.

(47) Both the pole body 104 and the cap 122 are manufactured in an injection molding process. The pole body 104 is directly formed by injection molding the contact pins 102 and possibly the insulating compound surrounding the contact pins 102, while the cap 122 is manufactured as separate injection molded part.

(48) After infilling the igniting mixture 116 the cap 122 is attached to the pole body 104 and is connected to the pole body 104 along the entire periphery of the igniter 100, for example by ultrasonic welding.

(49) It is possible to manufacture the pole body 104 and the cap 122 of different plastics.

(50) According to another embodiment, both the pole body 104 and the cap 122 consist of a thermosetting plastic and are fabricated by injection molding.

(51) The pole body 104 is formed directly by coating the contact pins 102, while the cap 122 is manufactured as a separate injection molded part. After infilling the igniting mixture 116, also in this case the cap 122 is attached to the pole body 104 and is connected to the pole body 104 along the entire periphery of the igniter 100.

(52) It is also possible to fabricate only the pole body 104 or only the cap 122 of a thermosetting plastic.

(53) Since ultrasonic welding is not possible in the case of thermosetting plastic, in the igniter 100 shown in FIG. 4 the cap 122 and the pole body 104 are connected by means of a suitable adhesive at plural locations by bondings 146.

(54) In this case two bonding surfaces are provided. On the one hand, the peripheral flat end face 128 of the cap 122 is bonded at the open end of the cap 122 to the peripheral flat shoulder surface 130 of the pole body 104. The shoulder surface 130 of the pole body 104 is offset from the end face 106 of the pole body 104 somewhat toward the free ends of the contact pins 102.

(55) The second bending surface is formed between the peripheral cylindrical inner circumferential wall 132 of the cap 122 and a portion of a cylindrical circumferential wall 144 of the pole body 104 that is level therewith.

(56) Since both the inner circumferential wall 132 and the end face 128 of the cap 122 and the circumferential wall 144 and the shoulder surface 130 of the pole body 104 are adjacent one another, the two bondings 146 could also be merged.

(57) It is also imaginable, however, to use only one of the described bondings 146.

(58) Each of the bondings 146 can be extensive and can be formed over the entire periphery, but can also be provided only at individual points or portions over the periphery of the pole body 104 and the cap 122.

(59) FIG. 5 shows a variant in which the connection between the cap 222 and the pole body 204 is made by locking engagement.

(60) Correspondingly, first engaging elements 246 and second engaging elements 246′ are formed at the cap 222 and at the pole body 204. The first engaging element 246 provided at the cap 222 is formed as peripheral engaging edge projecting radially inwardly at the inner circumferential wall of the cap 222 and being adjacent to the end face 128 of the cap 222.

(61) The second engaging element 246′ provided at the pole body 204 is formed as peripheral engaging projection protruding from the circumferential wall 144 of the pole body 204 and forming a rim of the end face 106 of the pole body 204. The first engaging element 246 and the second engaging element 246′ are engaged in a form-fit manner along the entire periphery.

(62) It is possible to provide, in addition to the engaging connection, also an adhesive connection, for example as described in the first embodiment between the end face 128 of the cap 222 and the shoulder surface 130 of the pole body 204 and/or the circumferential wall portions 132, 144 of the cap 222 and of the pole body 204.

(63) In a further embodiment the contact pins 102 and the bridge wire 110 consist of NiCr21Mo14W (material number 2.4602), NiCr23Mo16Al (material number 2.4605) NiMo16CrTi (material number 2.4610) or NiMo16Cr15W (material number 2.4819).

(64) Both contact pins 102 and the bridge wire 110 are made of the same material.

(65) It is also possible, however, to use different materials for the bridge wire 110 and the contact pins 102. In such case the contact pins can be made, for instance, of stainless steel (e.g. X2CrNiMo17-12-2 (material number 1.4404)).

(66) The FIGS. 6 to 8 illustrate an embodiment in which a seal 148 of a sealing compound which seals the joints between the cap 222 and the pole body 104 and, respectively, between the contact pins 102 and the pole body 104 in a gastight manner is provided between the pole body 104 and the cap 122 and/or between the contact pins 102 and the pole body 104.

(67) In the variant shown in FIG. 6 the igniter 100 is enclosed almost completely by a seal 148 in the form of a thin layer of a sealing compound made of a resin, adhesive, varnish or plastic material. Merely the end portions of the two contact pins 102 facing the end faces 108 of the contact pins 102, which have to include a respective electrically perfect contacting surface for connection to an electronic ignition device not shown, are not enclosed by the thin layer of the sealing compound.

(68) The seal 148 is produced by immersing the igniter 100 into a container containing the sealing compound. The sealing compound is so thin that it penetrates even the gap e.g. still existing after ultrasonic welding between the end face 128 of the cap 122 at the free end thereof and the shoulder surface 130 of the pole body 104 and coats the wall and side faces of the gap. It is possible that the sealing compound completely fills this gap.

(69) Also the exit hole 150 of the contact pins 102 from the pole body 104 is completely surrounded by the sealing compound so that also gaps possibly existing between the contact pins 102 and the pole body 104 are filled by the sealing compound.

(70) In the variant shown in FIG. 7 only the lower side of the pole body 104 including the two exit holes 150 of the contact pins 102 is covered by the seal 148.

(71) In FIG. 8 an embodiment is shown in which merely the gap between the end lace 128 of the cap 122 and the shoulder surface 130 of the pole body 104 is filled with the seal 148.

(72) The three variants shown can also combined with each other by filling the gap between the end face 128 of the cap 122 and the shoulder surface 130 of the pole body 104 with sealing compound in addition to immersing the igniter 100 into the sealing compound, for example. For this, preferably the same sealing compound as for the coating is used. Also the exit holes 150 of the contact pins 102 can be additionally sealed.

(73) The use of such seal 148 is possible, for instance, in combination with a bonding or engagement of the cap 122 with the pole body 104, but also for sealing or filling a gap between the cap 122 and the pole body 104 left during ultrasonic welding.

(74) In the embodiment shown in FIG. 9, the dimensions of the cap 122 are selected so that its height h, measured from the end face 128 at the free rim of the cap 122 to the outside of the closed end wall 134, is approx. 8 mm. Other lengths larger than the standard length of about 6.2 mm are also usable, the dimensions being selected so that the ignition chamber 124 can accommodate at least about 260 mg ZPP (zirconium potassium perchlorate). In the case of larger heights h of the cap 122 an amount of igniting mixture of up to 600 mg ZPP can be accommodated. For accommodating an amount of propellant of 600 mg preferably a height h of the cap 122 of 11.5 mm is provided.

(75) These specifications relate to the total amount of the igniting mixture 116 including the primary ignition charge 118 and the secondary ignition charge 120 and, respectively, including a possibly optionally added tertiary igniting charge.

(76) Compared to an igniter having standard dimensions, only the height h of the cap 122 but not the diameter b thereof is changed (measured at the outside of the cylindrical circumferential wall 136 of the cap 122). Also the dimensions of the pole body 104 remain unchanged so that the igniter 100 can also be mounted in standard situations.

(77) In accordance with a further embodiment, the cap 122 consists of two different plastic components. In the example shown in FIG. 9, a first relatively bard plastic component is used for the circumferential wall 136 of the cap 122, whereas an end wall 134 of the cap 122 consists of a softer more resilient plastic component. Advantageously hardness values for the relatively hard plastic component are within a range of Shore hardness of from D80 to D95 and for the softer more resilient plastic component are within a range of Shore hardness of from D30 to D80.

(78) This entails the fact that upon ignition of the igniter 100 the circumferential wall 136 yields only insignificantly vertically with respect to the longitudinal direction A and the gas pressure is guided in the direction of the end wall 134. In this way the opening behavior of the cap 122 is specifically influenced so that the end wall 134 breaks and the hot gas escapes at this location.

(79) Mechanical structural weakening zones such as embossments or a reduction of portions of the wall thickness are not necessary.

(80) The height h of the cap 122 in the longitudinal direction A can correspond to standard dimensions.

(81) This embodiment can also be perfectly combined with the afore-described embodiment, however. When a cap 122 having a larger height h is used which is adapted to accommodate a larger amount of igniting mixture 116 (as described before), a better guiding of the gas flow and a well-directed opening of the cap 122 at the predetermined locations, e.g. exclusively at the end wall, can be obtained by a cap 122 composed of two or more different types of plastic.

(82) In the embodiment shown in FIGS. 11 and 12 the cap 122 includes plural, in this case two or four weakening zones 152 in its cylindrical circumferential wall 136. The weakening zones are arranged to be offset along the periphery by 180° or 90°. Each of the weakening zones is formed in this example by a reduced wall thickness of the circumferential wall 136 (cf. FIG. 12).

(83) When activating the igniter 100 the weakening zone 152 is destroyed by the increasing internal pressure inside the ignition chamber 124 of the cap 122 so that within the area of the former weakening zones 152 a respective outlet orifice is released or created through which the hot gas can flow out of the igniter 100.

(84) The weakening zones 152 could also be formed by notches or embossments, for example.

(85) It is also possible to form the weakening zones 152 by an area made of a softer or more brittle plastic than the residual circumferential wall 136.

(86) A further weakening zone may be provided in the closed end wall 124 forming a cover of the cap 122. However, there can also be formed a structure constituting a reinforcement so as to ensure that the cap 122 is not opened in the area of the end wall 134.

(87) When using a cap 122 having a larger height h of the cap 122, as described above, and a related larger amount of igniting mixture 116, the lateral discharge of hot gas after ignition of the igniter 100 into a surrounding main propellant charge of an inflator is especially advantageous, because in this way uniform ignition of the propellant charge can be obtained.

(88) As described in detail before, the invention relates to a pyrotechnical igniter comprising especially one or more of the following features or combinations of features.

(89) A pyrotechnical igniter 100 for an inflator of a vehicle safety system comprising at least two contact pins 102 physically separated from each other by an electrically insulating compound and a bridge wire 110 connected to both contact pins 102 in an electrically conducting manner, wherein a fastening portion 112 in which the bridge wire 110 is welded to the contact pin 102 is provided at each contact pin 102, and wherein in a top view a minimum distance d between a rim of the fastening portion 112 and the insulating compound is about 0.01 to 0.5 mm, especially about 0.01 to 0.2 mm.

(90) It is preferred in this context that each contact pin 102 includes an end face 108 protruding from the insulating compound and the fastening portion 112 is arranged at the end face 108, the minimum distance d being measured from a rim 114 of the end face 108.

(91) It is preferred that the bridge wire is a CrNi wire.

(92) It is preferred that the bridge wire has a specific resistance of about 0.3 to 0.32 Ωmm.sup.2/m.

(93) It is preferred that the bridge wire has a diameter of approx. 20.8 to 21.5 μm.

(94) A pyrotechnical igniter for an inflator of a vehicle safety system comprising at least two contact pins 102 physically separated from each other by an electrically insulating compound, each contact pin 102 being provided with a chlorine-free gold coating 126.

(95) It is preferred in this case that at least one layer of the entire gold coating is formed by a flash gold coating.

(96) It is preferred that the thickness of the entire gold layer is at least 0.76 μm.

(97) It is preferred that to a body 128 of the contact pin 102 a flash gold coating is applied and to the latter a hard gold coating is applied.

(98) It is preferred that a nickel layer is applied between the flash gold coating and the hard gold coating.

(99) It is preferred that the nickel layer is deposited from a nickel sulfamate electrolyte or in a current-less manner.

(100) It is preferred that a coating including about 1.0 to 2.0 μm nickel is applied to the body 128 of the contact pin 102 and a gold layer having a thickness of at least 0.76 μm is applied to the nickel layer.

(101) It is preferred that the body 128 of the contact pins 102 consists of 1.4404 stainless steel.

(102) A method of manufacturing a pyrotechnical igniter, wherein it is preferred that the gold layer is applied in a galvanic process, chlorine traps being introduced into a purifying solution used in a preceding purifying step.

(103) It is preferred that to the body 128 of the contact pin 102 a palladium layer having a thickness of about 50-100 nm, preferably 70 nm, is applied and to the palladium layer a gold layer having a thickness of about 5-10 nm, preferably about 5 nm, is applied.

(104) An igniter for an inflator of a vehicle safety system, wherein a pole body of the igniter and/or a cap outwardly closing off the igniter consists of a plastic material having a substantially linear or cross-linked chain structure.

(105) It is preferred that the plastic material is linear polyphenylene sulfide.

(106) It is preferred that the plastic material is cross-linked polyphenylene sulfide.

(107) It is preferred that the plastic material is a glass-fiber reinforced polyamide.

(108) It is preferred that the glass fiber content in the plastic is about 50%,

(109) An igniter for an inflator of a vehicle safety systems wherein a pole body 104; 204 of the igniter 100; 200 and/or a cap 122; 222 outwardly closing off the igniter 100; 200 is made of thermosetting plastic.

(110) It is preferred that the cap 122; 222 is bonded to the pole body 104; 204 of the igniter 100; 200.

(111) It is preferred that the cap 122; 222 includes a peripheral flat end face 128 bonded to a peripheral flat shoulder surface 130 of the pole body 104; 204.

(112) It is preferred that a peripheral portion of an inner circumferential wall 132 of the cap 122; 222 is bonded to a peripheral portion of the circumferential wall 144 of the pole body 104; 204.

(113) It is preferred that the cap 222 includes first engaging elements 246 and the pole body 204 includes second engaging elements 246′ and the cap 222 is engaged in the pole body 204.

(114) It is preferred that at its free end the cap 222 includes a peripheral engaging edge that is engaged in a peripheral engaging projection surrounding an end face 106 of the pole body 204.

(115) A pyrotechnical igniter for an inflator of a vehicle safety system comprising at least two contact pins 102 and a bridge wire 110 connected to the two contact pins 102 in an electrically conducting manner, wherein the bridge wire consists of a nickel alloy with chromium at percentages of 11 to 24%, molybdenum at percentages of 12.5 to 17% as well as optionally additions of iron at percentages of 0 to 7% and/or tungsten at percentages of 0 to 4.5% and the specific resistance of the bridge wire ranges from 0.25 to 3 Ωmm.sup.2/m.

(116) It is preferred that the nickel alloy is selected from the group consisting of NiCr21Mo14W material number 2.4802, NiCr23Mo16Al material number 2.4605, NiMo16CrTi material number 2.4610 and NiMo16Cr15W material number 2.4819.

(117) It is preferred that the specific resistance ranges from 0.25 to 2 Ωmm.sup.2/m, preferably from 0.25 to 1.3 Ωmm.sup.2/m.

(118) It is preferred that the contact pins 102 and the bridge wire 110 are made of the same material.

(119) It is preferred that the contact pins 102 are made of austenitic stainless steel having a nickel content of 10 to 14% and a molybdenum content of 0 to 2.5%.

(120) It is preferred that the stainless steel is X2CrNSMo17-12-2 material number 1.4404.

(121) A pyrotechnical igniter for an inflator of a vehicle safety system comprising a pole body 104 including two contact pins 102 and a cap 122 outwardly closing off the igniter 100, wherein a seal 148 of a sealing compound is provided between the pole body 104 and the cap 122 and/or between the contact pins 102 and the pole body 104.

(122) It is preferred that the sealing compound used for sealing consists of a resin, adhesive, varnish or plastic.

(123) It is preferred that at least portions of the pole body 104 and/or the cap 122 are coated by the seal 148.

(124) It is preferred that the seal 148 completely covers the pole body 104 and the cap 122.

(125) It is preferred that the seal 148 is provided in a gap between the cap 122 and the pole body 104.

(126) It is preferred that the seal 148 is disposed between an end face 128 of the cap 122 and a shoulder surface 130 of the pole body 104.

(127) It is preferred that the seal 148 covers an exit hole of the contact pins 102 from the pole body 104 and surrounds at least portions of both contact pins 102.

(128) A pyrotechnical igniter for an inflator of a vehicle safety system comprising a pole body 104 including at least two contact pins 102 and a cap 122 outwardly closing off the igniter 100, wherein the length h of the cap 122 in the longitudinal direction A of the igniter 100 is about 7 to 15 mm, especially about 8 to 12 mm.

(129) It is preferred that the diameter b of the cap 122 is 5 to 11 mm, especially 6 to 10 mm.

(130) It is preferred that the cap 122 is dimensioned so that it can accommodate approx. 250 to 800 mg ZPP, especially approx. 260 to 600 mg ZPP.

(131) A pyrotechnical igniter for an inflator of a vehicle safety system comprising a pole body 104 including at least two contact pins 102 and a cap 122 outwardly closing off the igniter 100, the cap 122 including two different plastic components.

(132) It is preferred that an end wall 134 of the cap 122 is made of softer plastic material than a circumferential wall 150 of the cap 122.

(133) It is preferred that the end wall 140 of the cap 122 is made of plastic material with a Shore hardness ranging from D30 to D80 and/or the circumferential wall 150 of the cap 122 is made of plastic material with a Shore hardness ranging from D80 to D95.

(134) A method of manufacturing an igniter, wherein if is preferred that the cap 122 is fabricated by injection molding, wherein both plastic components are introduced to an injection mold in the same processing step.

(135) A pyrotechnical igniter for an inflator of a vehicle safety system comprising a pole body 104 including at least two contact pins 102 and a cap 122 outwardly closing off the igniter 100 and having a predetermined weakening zone 152 in which upon activation of the igniter 100 the material of the cap 122 yields under the internal pressure in the igniter 100, the weakening zone 152 being arranged in a lateral circumferential wall 150 of the cap 122.

(136) It is preferred that the weakening zone 152 is formed by at least a notch, an embossment and/or a material weakening.

(137) It is preferred that upon activation of the igniter 100 the weakening zone 152 forms a gas outlet orifice.

(138) All features of the above-described embodiments and examples can be freely combined with each other or exchanged for each other at the discretion of those skilled in the art.