Land vehicles – Wheeled – Attachment
Reexamination Certificate
2001-11-21
2002-08-06
Dickson, Paul N. (Department: 3618)
Land vehicles
Wheeled
Attachment
C280S729000, C280S742000
Reexamination Certificate
active
06428041
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns an airbag system for a motor vehicle.
Airbag systems for motor vehicles with one or more airbags are known in a very wide variety of embodiments and for a very wide variety of purposes. These systems can include sensor systems that measure the seat position of the protected occupant in relation to the relevant airbag and determine the time and extent of airbag deployment from the result of these measurements in order to trigger deployment of the airbag or airbags. DE 44 20 114 A1. discloses an airbag system for frontal and lateral protection in which the triggering device is an electronic control unit that detects the direction and intensity of a crash as well as the seat occupancy, and triggers the airbags individually or in combination as a function of the signals.
Also known is the use of pressure relief valves that stand in operative connection with a seat occupancy sensor system by means of a control unit in order to control the gas flow for the airbag as a function of the seat position of a vehicle occupant, and in particular to reduce said flow if the vehicle occupant is not in his predetermined seat position during a crash, but instead is in a forward-leaning (out-of-position) posture, or if a child restraint system is present on the relevant vehicle seat, or indeed if a child is present in the airbag's deployment zone (keep-out zone), so that the airbag does not act on the vehicle occupant with full gas pressure. It is also known to use multi-stage generators to control the gas flow in an airbag and thus the gas pressure therein.
Hence, from EP 0 836 971 A1 is known a passenger protection arrangement for a vehicle that has at least one airbag capable of being filled by an inflation device and that has a control unit connected to a sensor system for triggering and influencing the inflation device with regard to the filling characteristics of the airbag, wherein, in order to detect occupants in an out-of-position posture, a variety of elements are provided as components of the sensor system by means of which it is possible to detect the expansion behavior of a predetermined section of the airbag envelope. The signals generated by these elements can then be processed in the control unit to influence the inflation device. In this context, the elements can be designed as a tension member connected to the envelope section in the form of a cable, strap or hose associated with a displacement sensor in the form of a speed indicator. Moreover, magnetically active metal particles can also be associated with the tension member, in which case the displacement sensor here is then designed to detect magnetic asymmetries. Moreover, the tension member can have an associated pattern of stripes, which in turn is associated with an optical sensor for detecting the expansion behavior of the pattern of stripes. In addition, the elements can also take the form of a pressure sensing film or a piezoelectric element, either of which must be connected to the control unit by a signal transmission element. Furthermore, the elements can also take the form of a folding or expanding body, whose first end is attached to the predetermined envelope section and whose second end is attached to a stationary component, where the folding or expanding body has a reduced extension in a rest position and can be elongated in its extension by the inflation device. In addition, these elements can include at least one breakable element whose first end is attached to the folding or expanding body in the vicinity of a predetermined retaining section and whose second end is attached to a stationary component of the vehicle, so that the breakable element can be broken by the action of the inflation device to generate a signal, for example. This breaking of the breakable element can interrupt an electrical conductor to obtain a switching signal, by which means a control signal to alter the filling characteristics of the airbag can be generated by such methods as a characteristic curve in the control device if the signal is not detected within the predefined time period after triggering of the inflation device. Thus in every case the gas generator here is activated electronically as a function of a measured expansion characteristic of the airbag.
A similar construction is also known from EP 0 812 741 A1. This patent describes an airbag device in which the amount of gas delivered to an airbag by a filling device is accomplished by an unhindered forward movement of the airbag using a strip arranged in the interior of the airbag as a sensing medium. This strip is connected to the front portion of the airbag, and also is designed such that it advances along with the airbag. Here the travel distance and/or travel time is sensed, and an analysis unit is provided that determines the forward travel speed of the strip, and hence of the gas cushion traveling in the passenger compartment, and that controls the filling characteristics of the gas generator with an appropriate control signal. Hence, this is also a construction of an airbag system in which a gas generator can be appropriately controlled by means of an analysis and control unit.
A similar construction is also known from WO 99/65737, which was published during the priority period.
The airbag systems described above are thus all systems in which the gas stream blown into the airbag by the gas generator is electronically controlled with the aid of appropriate means positioned on the airbag for detecting and measuring the expansion behavior of the airbag. Such a construction is relatively complex and under some circumstances can also be subject to a certain susceptibility to malfunction.
In addition DE 198 16 075 A1, which was published during the priority period, discloses a safety apparatus for a motor vehicle with a multi-chamber airbag that has a tactile airbag with a contact function that can be quickly inflated with little energy, which can be inflated in the inflation area of at least one other airbag chamber, where it identifies by contact any obstacle that may be present and out of a normal position in this area. Connected to the tactile airbag is an electronic contact detection device that emits a control signal when contact occurs with the tactile airbag. The gas generator also includes a control device for the quantity of incoming gas that is connected to the contact detection device and that stops, or at least reduces, the gas generator's inflation function from continuing to inflate the airbag when it is acted upon by the control signal. Hence, the quantity of gas emitted by the gas generator is electronically controlled here as well.
Known from U.S. Pat. No. 5,899,488 is an arrangement wherein, to open the cover prior to deployment of the airbag, the gas generator first discharges into a cap or trough of a movable component associated with the gas generator on the side away from the cover, and this movable component is linked by a mechanism to the cover flap of the airbag cover. This discharge into the cap or trough displaces the component backward, away from the gas generator, while tearing the cover flaps so that the airbag exit opening is uncovered. A gas connection to the airbag itself is not established until the airbag exit opening is fully uncovered, so that the airbag can be inflated unhindered in front of the airbag exit opening. The capability to detect an out-of-position passenger is neither provided nor possible with such an arrangement.
In order to be able to protect the vehicle occupants beyond the duration of the first vehicle impact and even through a secondary impact in the case of a complex accident event, DE 92 11 421 U1 proposes a gas bag restraint system with a gas bag having at least two chambers, where the first, larger chamber encloses the second and is delimited by a wall whose material has greater gas permeability than the material delimiting the second chamber. The first chamber protects the vehicle occupants during the primary impact but collapses rapidly, while the sec
Sinnhuber Ruprecht
Wohllebe Thomas
Dickson Paul N.
Fleming Faye M.
Volkswagen AG
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