MXPA98004312A - Set and method of ignic - Google Patents

Abstract

An electrically conductive system that includes an apparatus and method in which an electric current is passed through at least two insulated sealed zones and a hollow insulated sealed space disposed therein and subjected to a vacuum, which serves as a discharge area for possible unnoticed pre-announcements accidentally produced by external factors

Description

SET AND METHOD OF IGNITION BACKGROUND OF THE INVENTION The present invention relates to a deflagration assembly and to a method for igniting a pyrotechnic impeller and more particularly to a system for inflating an air bag that releases the gas at the moment of impact to opportunely inflate a personal protective air bag. Its usefulness is not limited to that application. In the automotive industry, a large number of deflagration devices of different types have been used that can convert electrical energy into chemical energy in a matter of milliseconds to inflate protective airbags. Most of these prior devices include comparatively complex mechanisms although not always satisfactory to avoid premature and undesirable deflagration. An earlier device that includes an ignition assembly and which faces the possibility of a release including an ignition assembly and facing the possibility of an inadvertent release of energy "of US Patent No. 3,971,320" grants J.T.M. Lee »July 27, 1976» that uses an earth leakage »forms a coaxial conductor to the housing of a lighter to prevent accidental deflagrations. Such accidental ignitions »which may occur due to changes in external factors» such as electrostatic charge or radiant or electromagnetic energy or radio frequency »may cause serious damage to persons during the manufacturing process of ignitors or devices intended to be otherwise protected with air bag equipment. For greater caution against accidental ignition, comparatively complex arrangements have been used that are expensive and not always satisfactory. In this context we will mention two published European patents: No. 065S739A2 »inventor JH Evans» published on June 21, 1995 »which reveals an electrostatic spark gap discharge arrangement for two separate electrodes outside a pyrotechnic tank» on one side of a glass-metal seal, with a bridge conductor to the other seal, in close communication with a secondary pyrotechnic device and No. 745-519A1. inventor D.D. Hansen »published on December 9, 1996 that reveals a metal oxide varistor made of pol or pressed to protect the lighter from premature ignitions. Most of the above protective devices intended to prevent the premature ignition of the ignition assembly were of comparatively complex construction and assembly costly and of not always efficient operation and which required comparatively complicated manufacturing steps and additional parts for their assembly. The present invention provides a new and useful arrangement that is simple and inexpensive to manufacture and assemble. It requires a comparatively small amount of parts and little room and optimizes the use of several parts that are equally necessary for the normal development of ignition. at the same time unnoticed discharges of energy frequently produced in the previous devices by electrostatic charges created by external factors. Different other aspects of the present invention will become apparent to art technicians after reading the following disclosure.

BRIEF DESCRIPTION OF THE INVENTION More particularly »the present invention offers a conductive assembly of electricity comprising: a housing of preselected material defining at least two internal chambers. upstream and downstream »each chamber including a perimeter wall that defines it» with an electrically insulating senile material that extends transversely through it »in sealing relation with the perimeter wall that defines the chamber» the material being insulating sealant from one chamber at a preselected distance from the insulating sealing material of the other chamber »to supply a sealed chamber of insulating material empty between them and electrical conductors that have a portion thereof that extends in sealed relation through the insulating sealant material of the electricity of each chamber and the empty sealed chamber extending between them »with projecting ends upstream and downstream »respectively. The empty sealed chamber is intended to prevent the formation of possible undesirable pre-ignition sparks. Further »the present invention provides a method for charging and discharging electric power through a set of electrically conductive conduit extending in sealed relationship through sealed zones with first and second separated insulating material» to a discharge zone, the separation between the first and the second sealed zone with insulating material serving as an empty sealed chamber that receives the drainage insulated from high voltage electrostatic charges to prevent the undesirable formation of preignition sparks. It is understood that the art technicians may introduce different changes in one or several parts and in one or several of the different steps of the novel invention that is disclosed herein without departing from the scope and spirit of the present invention. For example, while the present invention is useful in a structure of a lighter »particularly that which is used to inflate an airbag» the new aspects of the present invention can be employed in a number of other electrical applications »such as switches electric »other explosive lighters and electric motors.

BRIEF DESCRIPTION OF THE DRAWINGS With reference to the drawings that disclose an advantageous embodiment of the present invention and a modification thereof: Figure 1 is a cross section of an igniter or ignition collar incorporating an advantageous embodiment of the present invention. The arrows indicate an electric flow path according to one aspect of the invention, and FIG. 2 is a cross-section similar to FIG. 1 of an ignition initiator or cast that incorporates a modification in the position of an insulating layer in the initiator. described in figure 1.

DETAILED DESCRIPTION OF THE INVENTION With reference to the drawings and in particular to FIG. 1, an ignition assembly 2 is disclosed which incorporates the novel aspects of the present invention and which can be particularly useful for igniting an explosive charge which in turn serves to inflate a bag of protective air as those currently used as a safety device in the automotive industry. It is understood that the use of the inventive aspects of the novel system described herein is that it is useful primarily for dissipating unwanted high voltage electrical loads that may be created by environmental or surrounding factors, should not be considered limited to ignition initiators. for inflating an airbag "but can be used in any of a number of situations in which an electrical transport occurs and in which it is desirable to dissipate leaks of electrical charges in a conductive system. In Figure 1, the developed ignition assembly Z includes a housing or collar 3 which can be made from any of a number of suitable materials. In this case it is made of a pre-selected cold rolled steel which includes three contiguous internal 'cylindrical chambers which are aligned axially about the longitudinal axis of the casing 3. The first two chambers' specifically an upstream chamber 4 and a current chamber below 6 includes »each» a perimeter wall defining it 7 and 8 »respectively» and each containing »a preselected electrically insulating sealing material 9 and 11» respectively »transversely extending therefrom» substantially normal to the axis longitudinal central of the casing 2 »in sealing relation with the perimeter wall defining the chambers 7 and B, respectively. The sealing material 9 of the illustrated embodiment is a seal T, preformed in the illustrated manner and melted into a carbon cup in a complementary manner. The seal 9 has an upper surface 18 and a lower surface 19 and transverse passages passing through it to receive terminal bolts to which the sealing material 9 is fused. The sealing material 11 of the illustrative embodiment is also formed as a seal cylindrical »with an upper surface 21 and a lower surface 22 and transverse passages for receiving terminal bolts to which the sealing material 11 is fused. In an advantageous embodiment of 1 to the present invention, the upstream sealant , of the upstream chamber 4, can be of a ceramic filled molten seal glass containing eg. Cobalt oxide and the sealing material 11, of the downstream adjoining chamber 6, can be of a preselected molten glass material which can be of a chemical composition substantially similar to the known glasses, commonly used for glass-metal seals Terminal assemblies associated with refrigeration compressors, charged by ex. aluminum oxide. In the illustration, the downstream face 19 of the upstream electricity insulating sealing material 9 of the chamber 4 is separated from the upstream face 21 of the downstream electricity insulating material 11 »of the current chamber below 6, to provide a novel vacuum sealed vacuum chamber »of preselected volume 12 between them. Note that with the innovative separating arrangement that forms the empty chamber the technicians B in the matter, the volume of the empty sealed chamber 12 and the volume and chemical composition of the upstream and downstream insulating sealing materials 9 and 11 »can vary selectively according to the requirements of a particular application and the desired results. When the present invention is employed to initiate the ignition of an air bag, the empty sealed chamber preferably has a volume of approximately 0.00265 cubic inches "with a diameter of approximately 0.260" and a thickness of approximately 0.050". According to the present invention it is important that the empty sealed chamber 12 serves as an insulator for normal imposed voltages and that the chamber 12 is a surface conductor for inadvertently applied voltages that may be created by undesired environmental factors, such as static electric charges. changing radiant energy »changing electromagnetic energy or changing radiofrequencies. In these cases, the current moves along the surfaces 19 and 21, both upstream and downstream of the sealing material 9 and 11, as shown in FIG. 1, passing through the empty chamber 12 towards the steel housing 3. »To be dissipated with insignificant consequences. The hollow sealed chamber 12 is partially in a vacuum state to improve the deposition of any unwanted high voltage inadvertently produced in the environment. This vacuum or partial pressure of the empty chamber 12 is created when the upstream and downstream senator materials are initially heated to melting temperature and then cooled which causes the gas trapped between them to contract to form a vacuum partial. The gas is that of the atmosphere of the furnace in which the melting is carried out, preferably nitrogen "although a reducing gas can also be used, particularly if it is desired that the transition metal oxides that are produced in the surface reduction of the glass Senator will produce a thin conductive film on surfaces IB and 19. In this case, an arc can be formed on the outside of the empty chamber, although in a location isolated from the explosive chamber. If natural gas atmosphere is used in the furnace, traces of carbon monoxide, the residual fixative of the sealing materials of the pelletized seals may also be present along with methane, hydrogen and carbon dioxide. As seen in Figure 1 of the drawings, the disclosed electrically conductive assembly includes at least two electrically conductive terminal pins 13 which are arranged in a pre-selected separate relationship about the longitudinal central axis of the adjoining upstream isolated chambers and downstream 4 and S. These electrically conductive pins 13 can be alloy 52 »nickel-plated steel. It is understood, however, that the separation, chemical composition and amount of such bolts may vary according to the use and the desired results. The spaced pins 13 'which are substantially parallel to each other, are separated from the walls 7 and B defining the perimeter of the chamber »a central portion of each bolt member 13 extending in glass-sealed relationship through the insulating senator material of glass 9 and 11"respectively" of each upstream and downstream chamber 4 and 6"respectively and through the sealed chamber with pressure or partial vacuum 12 lying between them. The ends of the projecting electrically conductive bolts 13 serve as loading and unloading areas respectively and the closed insulating chamber with partial pressure 12 allows, as described above, the formation of an arc of sparks between the bolts. 13 and the steel housing 3 which is isolated from the explosive charge 16 »to prevent the formation of undesirable pre-sparking sparks between the bolts 13. As seen in Figure 1 can advantageously be used a pre-selected ceramic electrically insulating sealing material 14 facing the downstream face 22 of insulating sealing material 11 »with the separated electrically conductive bolts 13 extending therethrough. As also shown in FIG. 1, the downstream ends of the bolts 13 terminate in a contiguous third, axially aligned internal chamber 16 which can be used in the disclosed embodiment as an ignition chamber for an air bag. air that is inflated by means of an explosive charge. The downstream ends of the bolt may have an appropriate jumper wire or circuit 7 (shown schematically) electrically connected thereto so as to be able to ignite an explosive charge inserted in the explosion chamber 16. If the camera 16 is provided with a lip extending radially inward at its upper end »the axial thickness of the lip can help to define the axial height of the recess 12» the position of the pelletized seal 11 being able to be determined by moving it until it comes into contact with the lip. With reference to figure 2 of the drawings »describing an ignition assembly» whose parts are »mostly» similar to those of the structure of figure 1 »it can be seen that the preselected ceramic insulating material 14 can also be arranged current below the downstream side 19 of the upstream insulating sealed material 9 »in the upstream chamber 4» instead of a downstream chamber 6 »as shown in figure i. According to the novel method for charging and discharging electric current revealed in the present »electric current is passed from an area of electrical changes of a current source (not shown) through a conductive set of electricity that extends in sealed relationship through sealed first and second sealed zones, serving the space between them as a hollow sealed chamber to reduce possible undesirable pre-ignition sparks of the electrically conductive assembly. The normal ignition voltage is 9-12 volts DC »with an ignition current of characteristically 1» 2 A. The static electricity voltages are high »of about 1,000 to 25,000 volts with a current greater than 1 , 2 A in 3 milliseconds needed for ignition. Loading the sealed material 11 with alumina »the sealing material retains its integrity sufficiently so that the dimensions of the hollow chamber 12 do not vary substantially. Such dimensions are relatively flexible, the important thing is to provide a defined »partially evacuated space. In order to isolate the ignition cable from these voltages, it is desirable, in addition to the incorporation of the recess 12, to ensure that said arc is produced transverse of the surfaces 19 or 21 and not on the surface 22 and that oxides can be used for this purpose. transition metal of the sealing material 9 to produce a surface conductive state »cobalt can advantageously be used as the metal oxide.

Claims (18)

NOVELTY OF THE INVENTION CLAIMS

1. - An assembly characterized in that it comprises: a housing of electrically conductive material that defines at least two internal chambers »upstream and downstream» each of said internal chambers including a perimeter wall having a sealant material insulating the electricity extending transversely therethrough, in sealing relationship with said perimeter walls defining the chamber "the insulating sealing material of a chamber being separated from the insulating sealing material of the other chamber" to provide a sealed chamber of insulating material empty between them and a conductive set of electricity having a portion extending in sealed relation through said insulating senator material of each chamber and the empty sealed chamber extending between them, with portions of upstream and downstream of said conductor set of electricity that serve as portions of charge a and discharge, respectively, and means in said empty insulated sealed chamber to dissipate high transient voltages and prevent possible undesirable discharges through said discharge portions.

2. The assembly of claim 1 »characterized in that said housing defining said internal chambers is a preselected cold rolled steel and part of an ignition assembly.

3. The assembly of claim 1 »characterized in that said insulating sealing material that extends transversely in each chamber is a pre-selected insulator capable of forming a conductive bridge through said empty insulated sealed chamber that lies between them» acting said insulating sealant material as an insulator with normal operating voltages and being a surface conductor with high voltages.

4. The conductive assembly of the electricity of claim 3 »characterized in that at least one of said transversely extending insulating materials is a preselected glass material.

5. The assembly of claim 3 »characterized in that both insulating sealing materials that extend transversely are of preselected glass» one of which is a ceramic glass-filled material and the other is a different pre-selected glass material »being melted said glass materials to said walls defining the chambers and said electrically conductive assembly "contracting the gas contained in said empty insulated sealed chamber" between said materials, during the cooling subsequent to said fusion, to form a partial vacuum in said chamber be isolated

6. The assembly of claim 1 »characterized in that said housing has a longitudinally extending axis with two internal chambers arranged in successive alignment along said central axis of said housing.

7. The assembly of claim 6 »characterized in that said assembly includes at least two members of electrically conductive pins arranged in a preselected separate relation about said central axis extending longitudinally of said two internal chambers and in a separate relation. of said perimeter walls defining said chambers »a portion of each bolt member extending in sealed relation through said insulating sealing material of each chamber and of the hollow chamber that is between them.

8. The assembly of claim 7, characterized in that each of said electrically conductive bolt members are alloy 52 »nickel-plated steel.

9. The assembly of claim 1 »characterized in that said empty chamber has an approximate volume of 0.00265 cubic inches, with a diameter of approximately 0.260" and a thickness of approximately 0.050".

10. The assembly of claim 1, characterized in that at least one of said two internal chambers has a preselected ceramic insulating sealing material successively facing the downstream side of said insulating sealing material »extending both materials transversely facing each other. said chamber in sealing relation therewith.

11. The assembly of claim 1 »characterized in that said confronting successive insulating material is advantageously arranged in at least said downstream chamber. 12.- The set of the rei indication 1, characterized in that said housing includes an ignition chamber within which extends a downstream end of said electrical conductive assembly »said downstream end of said conductive assembly of electricity having an ignition means electrically connected thereto. »Capable of igniting a charge arranged in said ignition chamber. 13. An ignition assembly for an airbag characterized in that it comprises a cold-rolled steel casing that includes three adjoining internal chambers "aligned axially about the longitudinal central axis of the casing" each of said aligned chambers including a perimeter wall which defines it, the first two isolated upstream chamber chambers serving »each having insulating sealing material of the preselected glass electricity that extends transversely therethrough, in sealing relation with said perimeter walls of said respective chamber the insulating sealant material of said upstream chamber being filled with ceramic melted glass sealant and said sealing material of said adjoining downstream chamber of pre-selected molten glass separated from said senator material of ceramic charged glass of said upstream chamber "for supply a camera empty insulating material between them, which has a preselected approximate volume of 0.00265 cubic inches with a diameter of approximately 0.260"and a thickness of approximately 0.050", to be able to form a conductive bridge through it, acting said glass insulating sealant on each side of said empty chamber sealed as an electrical insulator of normal operating stresses imposed and as a surface conductor of high imposed stresses that may be inadvertently created by external voltage-creating factors »contracting the gas contained in said sealed insulated vacuum chamber during the insulating seal on cooling after the glass sealing operations to form a partial vacuum in said empty insulated sealed chamber »at least two electrically conductive pins 52» nickel-plated steel being disposed in a preselected separate relation about said axis central longitudinal of dic have sealed chambers insulated from upstream and downstream and in pre-selected separate relation from said perimeter walls defining said chambers »each bolt member extending in sealed glass relation through said glass insulating sealant material of each upstream chamber and downstream and the empty sealed chamber that is in the middle »serving the ends of said bolts as loading and unloading, respectively, and receiving said insulated sealed chamber empties possible undesirable preignition sparks between the bolts, said face having said downstream of said glass insulating material of said downstream chamber a preselected ceramic insulating sealing material facing said downstream face with said main body of said separate electrically conductive bolts extending therethrough »terminating the ends of said bolts in said third c contiguous aligned chamber serving as an ignition chamber for an explosive charge that inflates an air pocket, said ends of said bolts forming an ignition circuit electrically connected therebetween, capable of igniting said explosive charge. 14. A method for charging and discharging electric current characterized in that it comprises: passing an electric current from a current source through a conductive assembly of electricity extending in sealed relation through sealed first and second sealed zones, towards a discharge area, serving the space between isolated first and second sealed chamber hollow to receive possible undesirable preignition sparks of said electrically conductive assembly. 15. The method for charging and discharging electric power of claim 14. characterized in that it includes introducing gas into said empty sealed chamber "between said first and second isolated areas during the sealing of said separate isolated areas" said gas contracting to form a vacuum of partial pressure in said empty sealed chamber. 16. The method for charging and discharging electric current of claim 15 »characterized in that said isolated areas are sealing glasses of different chemical composition. 17. The method for charging and discharging electric current of claim 14 »characterized in that it includes applying concentrated heat of ignition in said discharge zone to ignite an explosive charge disposed therein. 18. A method for making an ignition assembly characterized in that it comprises forming a housing of conductive material with axially aligned cylindrical chambers defined by walls of said casing, the first of said chambers being of a greater diameter than the second of said chambers. to define a stage between them »insert in this first chamber a preformed glass seal with an inverted T-shaped cross section» with a rod pointing outwards and a head with an internal face »whose perimetric portion rests at said stage» insert in said second chamber a second preformed glass seal »insert terminal bolts through aligned openings of said T-shaped seal and said second seal» keeping the facing surfaces of said T-shaped seal and said second seal separated from each other. introducing gas into the space between said seals and melting said seals to said housing and said terminal bolts.