Ammunition and explosives – Jacketed or cartridge gas generator
Reexamination Certificate
2002-03-04
2004-04-13
Tudor, Harold J. (Department: 3641)
Ammunition and explosives
Jacketed or cartridge gas generator
C102S202500, C102S202900, C102S202140, C280S741000
Reexamination Certificate
active
06718884
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an inflator for filling up an air bag for a motor vehicle or an inflatable article, and more particularly to an initiator (an electric trigger device) assembly for igniting a propellant (that is, a gas generating agent) in an inflator.
PRIOR ART
An initiator for inflating an air bag of a motor vehicle or the other expansible article includes an initiator assembly for igniting a propellant (a gas generating agent) stored in a housing of an inflator. The inflator activates the propellant (the gas generating agent) with activation of the initiator assembly so as to generate a gas for filling the inflatable article. The initiator assembly generally has an outer shape or includes a member for being connected to a supporting structure (for example, a structure in an inner tube of the inflator).
Conventionally, there has been known an initiator having an outer metal casing with a boss or a collar for connecting to an inflator housing. The collar is positioned on an outer periphery of an insulating material surrounding a conductive pin of the initiator. Further, in a design of another known initiator assembly, there has been known a cover having an injection-molded portion made of a plastic material surrounding an initiator. Such an initiator assembly is disclosed, for example, in JP-A 9-506965 and JP-A No. 11-321541.
In JP-A 9-506965, there is disclosed an initiator assembly in which a casing is made of a metal wall mounted to an metal end plate, and is provided with a molded product made of a plastic material so as to be formed in such a manner as to surround an end plate and a part of an electrode inserted to the end plate.
Further, in JP-A No. 11-321541, there is disclosed an initiator assembly having an inserted member which is injection-molded with an insulating material to be unified and being characterized by a shoulder portion having a comparatively short length and engaging with a trigger device adapter.
However, it is desired to make it further easier to connect the initiator assembly to the inflator housing as well as reducing a size of the injection-molded portion of the plastic material. However, it is impermissible that such the initiator aspect applies a further load to production of the initiator assembly and increases a manufacturing cost of the initiator assembly.
DISCLOSURE OF THE INVENTION
The present invention is made so as to solve the problems mentioned above, and an object of the present invention is to provide an initiator assembly which can be easily manufactured without increasing a cost, and can be easily and securely connected to a connector at a time of being used.
In accordance with the present invention, there can be provided an initiator assembly in which an inflator is improved. The initiator assembly ignites and burns a priming arranged close to a conductive pin of the initiator when it is activated with an igniting signal received by the conductive pin. The initiator assembly includes an initiator and a collar assembly joined to the initiator. In addition to at least one conductive pin, the initiator can have a cap member (a charge holder) made of a metal wall surrounding the priming to be ignited when the igniting signal is received. The collar assembly holds the initiator with respect to a housing of the inflator even after being activated.
The initiator assembly according to the present invention corresponds to an initiator assembly in which an initiator used for igniting a priming and having at least one conductive pin and a metal collar for holding the initiator assembly with respect to an inflator are integrally formed by an insulating material injection-molded between both members. In the case of employing a plastic material capable of being injection-molded as an insulating material, the injection-molded plastic material is solidified so as to form a molded resin portion, which connects integrally the initiator with the metal collar. In other words, the initiator, the metal collar and the insulating material existing between both members are simultaneously integrated due to the injection-molding of the insulating material so as to form the initiator assembly. In this case, in the present specification, for convenience of explanation, a combination of the injection-molded insulating material and the metal collar is referred as a collar assembly, and a combination of the collar assembly and the initiator is referred as an initiator assembly.
The collar assembly includes the injection-molded insulating material (hereinafter, also refer to as an insulating material in the same meaning) and the metal collar, and the metal collar is fixed and joined to the insulating material made of the injection-molded plastic material during an injection-molding process. The insulating material is useful for insulating one conductive pin from a second conductive pin, or in another aspect, the insulating material is useful for insulating one conductive pin from another conductive component in a different electric potential when the one conductive pin receives the igniting signal. The metal collar is a single integral piece and can be defined as one including a body portion and a shoulder portion. In the body portion, a front end annular cylindrical body portion thereof is arranged to be fitted and fixed to an outer periphery of the insulating material made of a molding plastic which is injection-molded to surround two conductive pins normally comprising a center pin and a grounding pin, the conductive pin extends into a cylindrical body portion (that is, a rear half portion) extending rearward, and a connector connected to the conductive pin is received in the inner space of the rear cylindrical body. In this metal collar, it is desirable that the rearward extending cylindrical body portion is formed so that the inner periphery thereof is not covered with an insulating material (that is, an injection-molded resin or the like) and the metal collar is exposed. This is for unfailingly preventing a connector arranged in the inner space of the circular portion from dropping out due to an impact at a time of activation of the initiator or the like.
The shoulder portion can be formed at a position at which the metal collar is separated into substantially a front half portion and a rear half portion, and is protruded outwardly in the radial direction from the body portion so as to be contacted and engaged with an engaging portion of the inflator housing. A mutual engagement between the shoulder portion and the engaging portion of the inflator housing controls a relative positioning of the initiator assembly with respect to the inflator housing before and after activating the initiator assembly. The outward position of the shoulder portion defines an outer length or size of the metal collar.
The initiator assembly according to the present invention can be formed, for example, as a structure in which the priming is stored in the charge holder composed of a cylindrical metal wall mounted to a metal eyelet (an end plate), the metal eyelet has a perforated cylindrical shape and a central hole is filled with an electric insulating body (normally made of a glass). In this case, the center pin of the electrode goes through the insulating material in the metal collar, continuously goes through the electric insulating body in the eyelet, and a front end thereof is connected to the priming. Further, the upper surface of the eyelet is in contact with the priming, and the second conductive pin, that is, a front end of the grounding pin of the electrode is connected to the lower surface of the eyelet in a state capable of turning on electricity. As the priming stored in the charge holder, a zirconium-potassium perchlorate material can be used. Further, the means for triggering the priming upon the igniting signal is provided between the center pin and the eyelet. That is, it is constituted by a resistance line connected between members.
The initiator assembly according to the present invention can accompany with the following feature
Katsuda Nobuyuki
Yabuta Mikio
Birch & Stewart Kolasch & Birch, LLP
Daicel Chemical Industries Ltd.
Tudor Harold J.
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