Ammunition and explosives – Igniting devices and systems – Laser or light initiated
Reexamination Certificate
1999-02-19
2002-10-29
Jordan, Charles T. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Laser or light initiated
C102S201000
Reexamination Certificate
active
06470801
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This is a national phase of copending International Application PCT/DE97/01700, filed Aug. 8, 1997, which designated the United States.
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a configuration for triggering a restraining device in a motor vehicle.
Such a configuration fires the firing elements of the associated restraining device by light signals and is known from Published European Patent Application EP 0 641 689 A2. For this purpose, the known configuration has a triggering device that contains a control circuit for controlling a light source. An optical waveguide is used to transmit to the firing element an optical firing signal that is emitted by the light source. The monochrome firing signal has a sufficiently large amount of energy to optically fire the firing material contained in the firing element.
The known configuration does not have any functional monitoring whatsoever of the firing circuit that is composed of the optical waveguide and the firing element. If the firing circuit which is composed of the optical waveguide and firing element has an optical break, so that if, for example as a result of incorrect assembly or unsatisfactory repair, the firing element is no longer correctly plugged onto the optical waveguide or the optical waveguide has a severe bend or even a fracture, the high-energy optical light signal/laser signal generated as a result of a triggering request can emerge from the optical waveguide at the end of the optical waveguide or at the fracture without impedance. A vehicle occupant or a servicing or repair technician may be injured, in particular in the eyes, by such an emerging, high-energy light pulse, and at the same time a triggering request can be generated, for example, even when a vehicle is stationary in a workshop, as a result of a hammer blow against a sensor unit of the configuration. In addition, the vehicle may be set on fire. On the other hand, the restraining device can no longer be triggered satisfactorily in the event of an accident when the firing circuit is faulty.
German Patent DE 42 24 166 C2 discloses a configuration in which a triggering device is connected to a firing device via an optical waveguide. An optical firing signal which is transmitted to the firing device by the triggering device is converted by a converter in the firing device into an electrical signal by which an electric firing element of the firing device, usually a firing cap with a heating wire which is enclosed in the firing powder, is fired.
In such a configuration, numerous opto-electrical and electro-optical converters are necessary. In the case of a defect in the electrical part of the firing device, the optical waveguide can still be supplied with a high-energy optical firing signal, with the disadvantageous consequences described above.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a configuration for triggering a restraining device in a motor vehicle that overcomes the above-mentioned disadvantages of the prior art devices of this general type, in which a maximum of safety can be achieved for the vehicle occupants despite a low level of expenditure on components.
With the foregoing and other objects in view there is provided, in accordance with the invention, a configuration for triggering a restraining device in a motor vehicle, including: a light source emitting an optical firing signal; a triggering device having a control circuit connected to and controlling the light source and initiating an optical check signal to be emitted by the light source; a firing element associated with a restraining device and outputting a light signal; an optical transmitter optically coupled to the firing element and to the light source for transmitting the optical firing signal emitted by the light source to the firing element; a light sensor optically coupled to the optical transmitter and receiving the light signal transmitted by the firing element; the triggering device having an evaluation circuit connected to the light sensor for evaluating the light signal received by the light sensor, the evaluation circuit generating a disable signal in dependence on an evaluation of the light signal for preventing an emission of the optical firing signal.
Here, in the first instance, an optical firing signal can be emitted, initiated by the control circuit, in order to fire the firing element. In the case of a firing process, the firing material in the firing element is caused to explode by the energy contained in the firing signal. As a result of which a housing of the firing element which holds the firing material is, if appropriate, blown apart at a predetermined fracture point and the energy which is released causes a gas generator which is disposed in the vicinity of the firing element to release gas. The gas that flows out fills, for example, a known airbags, but may also be used to pretension a seatbelt pretensioning device as restraining devices in a motor vehicle. The firing element is consequently fired directly by optical devices without the firing process being preceded by a conversion of the optical firing signal into an electrical signal. An optical transmitter, for example an optical waveguide, is used to transmit the optical firing signal from the triggering device to the firing element.
On the other hand, an optical check signal for functional checking of the firing circuit can be transmitted from the triggering device to the firing element. The triggering device in turn contains the evaluation circuit for evaluating the light signal that is transmitted to the triggering device via the optical transmitter, for example the above-mentioned optical waveguide, and is sensed by a photo-detector. In this way, light signals can be sensed and processed and, for example, transmitted back to the triggering device as a response to check signals that have been emitted. As a function of the evaluated, received light signal, the evaluation circuit generates a disable signal that subsequently prevents emission of the firing signal. Preferably, a warning device, which is for example optical or audible and which alerts the vehicle occupant to a malfunction in the vehicle occupant protection system, in particular in the firing circuit, is also activated as a function of the evaluated, received light signal. If appropriate, an entry in a programmable, nonvolatile memory takes place.
Consequently, by the configuration according to the invention it is possible to monitor the operational capability of the firing circuit composed of the optical transmitter and the firing element, on a permanent or cyclical basis or when the vehicle occupant protection system is put into service/initialized, a firing signal being prevented from being emitted if a defect is discovered. The protection of vehicle occupants is significantly increased without additional expenditure in the form of a plurality of optical waveguides and/or converters being necessary.
Preferably, such a light signal which is sensed by the photo-detector of the triggering device is the check signal which is emitted and reflected at a reflection element. The reflection element is disposed here between the firing element end of the optical waveguide and a firing material of the firing element, the optical transmitter not necessarily being restricted to an optical waveguide in this or in other advantageous embodiments of the invention.
When the optical waveguide is functional and the firing element on the reflection element is correctly attached to the optical waveguide, the check signal is preferably completely reflected and transmitted back via the same optical waveguide to the triggering device where it is sensed by the photo-detector and evaluated by the evaluation circuit. The degree of transmission of the reflection element is dimensioned in all cases in such a way that a large part of the light intensity of the check signal is reflected and, if appropriate, only a small proportion of light is let through to
Acklin Bruno
Dirmeyer Josef
Kuhn Gerhard
Swart Marten
Wicke Markus
Greenberg Laurence A.
Jordan Charles T.
Lerner Herbert L.
Semunegus Lulit
Siemens Aktiengesellschaft
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