Ammunition and explosives – Igniting devices and systems – Electrical primer or ignitor
Reexamination Certificate
1998-09-21
2001-05-08
Tudor, Harold J. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Electrical primer or ignitor
C102S202700, C102S202140, C102S530000, C102S202100, C280S741000
Reexamination Certificate
active
06227115
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a detonator device having a detonator circuit for tripping a passenger restraint device in a motor vehicle.
One system for tripping a passenger restraint device in a motor vehicle is known from European Patent Application EP 0 471 871 A1. The system has an evaluation unit, disposed centrally in the vehicle, for evaluating acceleration and crash signals that are furnished by a sensor device. Detonator devices that include detonator circuits are disposed near the associated passenger restraint devices, such as an air bag, belt tensioner, and so forth, are connected to the evaluation unit via a line/bus. If the evaluation unit detects an accident in which at least one of the passenger restraint devices should be tripped, then an encoded trip command is sent from the evaluation unit to the corresponding detonator device. In the detonator circuit of the detonator device, the trip command is decoded and converted into control commands, by which the energy, stored in an energy-storing capacitor of the detonator device, is transmitted to a passenger restraint device detonator element/primer capsule that is electrically connected to the detonator device.
A conventional detonator element in the form of a primer capsule has two firing pins that are connected via a detonator wire. The detonator wire is disposed in a firing chamber, which is formed by both a holder of the primer capsule and a plastic cap. The firing chamber is filled with a detonating powder, which when the detonator wire heats up sufficiently explodes and blows off the lid of the plastic cap. The sheath of the plastic cap is surrounded by a metal cap that is intended to prevent electromagnetic radiation into the firing pins and detonator wire. A lower part of a gas generator sheath surrounds the primer capsule and at the same time forms a plug body for the firing pins. The gas generator sheath surrounds a generator chamber, in which capsules are disposed that are supplied with energy by the explosion of the detonating powder and thereupon release gases which fill an air bag connected to the gas generator. via the plug connection, the primer capsule is electrically conductively connected to an evaluation unit disposed centrally in the vehicle, and for tripping the associated passenger restraint device, a firing pulse that carries sufficient energy is transmitted via a line between the evaluation unit and the primer capsule.
The known primer capsule typically has a short-circuit bridge disposed between the firing pins. Such a short-circuit bridge prevents unintended detonation of the detonating powder, by unintentional application of a direct voltage to the firing pins protruding from the plug body, before a mating plug is plugged into the primer capsule.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an ignition device for tripping a passenger restraint device in a motor vehicle which overcomes the above-mentioned disadvantages of the prior art devices of this general type, in which an extremely small in size tripping device is provided, so that it can be accommodated in a steering wheel, for instance, and moreover needs only a small number of components and is simple to produce.
With the foregoing and other objects in view there is provided, in accordance with the invention, a detonator device for tripping a passenger restraint device in a motor vehicle, including: a detonator circuit; and a holder housing the detonator circuit, the holder having firing pins for receiving a detonator element.
A holder containing the detonator circuit has firing pins for receiving the detonator element. A detonator element connected to the detonator device has substantially the same configuration as the known primer capsule, except that instead of the firing pins protruding from the body of the primer capsule, bushes are provided for receiving the firing pins, which are now secured to the detonator device. According to the invention, the detonator device accordingly includes a preferably three-dimensional circuit holder with which at least the firing pins are integrated.
The short-circuit clip of conventional primer capsules can thus be dispensed with.
The detonator wire, typically embodied as an incandescent filament, is preferably secured directly to the firing pins protruding from the circuit holder. The primer capsule as a structural unit to be slipped onto the detonator device is thus dispensed with. The firing pins are in any case, according to the invention, an integral component of the circuit holder that receives the detonator circuit. In this advantageous feature as well, the short-circuit clip, which particularly in conventional primer capsules is indispensable for the sake of nonhazardous handling, is then omitted. According to the invention, the primer capsule and the detonator device are no longer connected electrically and mechanically to one another via a plug connection. The firing pins, as an integral component of the circuit holder of the detonator device, are produced jointly with the holder, and at the same time.
Not until a further step is the detonator wire pressed, soldered, or glued to the firing pins, or simply wrapped around them (wire-wrap binding). The firing chamber, defined as the surroundings of the detonator wire, is thereupon filled with pyrotechnical detonating powder.
The detonator device preferably includes plug pins, which are also an integral component of the holder. via these plug pins and a corresponding plug connector, the detonator device is connected via a bus to the evaluation unit. If a voltage is mistakenly applied to the plug pins of the detonator device before the detonator device is connected to the evaluation unit, then the detonator wire, because of the detonator circuit connected upstream of the firing pins, is not heated and thus prevents inadvertent tripping of the passenger restraint. Because the firing pins and the circuit holder are a structural unit, it becomes unnecessary to provide a short-circuit clip between the firing pins.
Space is also saved by omitting a plug connection between a conventional primer capsule and a conventional detonator device that lacks integrated firing pins.
In an especially advantageous feature of the invention, the holder is embodied as a conductor track structure stamped out of a metal strip, and the firing pins are embodied integrally with the conductor track structure. Because of an advantageous three-dimensional form of the conductor track structure and because the plug pins and the conductor track structure are likewise embodied integrally, the overall detonator device becomes extremely compact. Therefore, there is space for housing the holder even in the steering wheel or in the side door of the vehicle.
In a further advantageous feature of the invention, the holder is embodied as a three-dimensional plastic body with applied conductor tracks, and the firing pins are firmly joined to the plastic body, preferably by being spray-coated, and are thus inseparably joined to the plastic body. In terms of the compactness of the detonator device, it is also advantageous here to embody the plug pins from the outset as an integral component of the holder. The advantages of this feature are the same as those of the feature of the invention described above.
The three-dimensional circuit holder allows configuration freedom for the entire detonator device in terms of its three-dimensional construction, and can thus be adapted extremely simply, not only to the spatial characteristics of the installation site, but also to both the mechanical interfaces with the gas generator and the plug interface with the bus.
In accordance with an added feature of the invention, there is a detonator wire electrically connecting the firing pins.
In accordance with an additional feature of the invention, there is a plastic sheath surrounding the holder.
In accordance with another feature of the invention, there is a metal sheath surrounding the holder.
In accordance with
Christoph Markus
Dirmeyer Josef
Gruber Robert
Plankl Christian
Probst Heinrich
Greenberg Laurence A.
Lerner Herbert L.
Siemens Aktiengesellschaft
Stemer Werner H.
Tudor Harold J.
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