SE469330B - SEQUENCE INDICATOR IN AIR CUSHION FOR VEHICLES - Google Patents

Description

The size or weight of the airbag system. All attempts to somehow reduce the size of this device, however, result in a problem that in certain extensive collisions the piston bounces back towards the cylinder end and returns to its interior. position before the gases from the inflator have had time to impede the movement of the sensing mass. Thus, the device in a reduced version can give a false picture of reality. This problem is due to the fact that it takes as much as 15 ms from the time the sensor indicated that the airbag should be inflated and to the time when there is a significant gas pressure in the inflator.

The present invention represents an improvement over the technique described in the above-mentioned patent specification in that it utilizes the spark plug or spark plug gas to prevent the movement of the sensing mass or piston. The gas is available for 1 to 2 ms after the release of the sensor.

The main object of the present invention is to provide a miniature device which indicates that a car had an accident at the time of the development of the airbag.

Another object of the invention is to provide a miniature device which, independently of the collision sensor, indicates that a car had an accident at the time of the development of the airbag. This will provide accurate information in the event that the sensor itself has been out of order.

A further object is to provide a means for forcibly determining the manufacturer's liability when an airbag develops due to an accident.

A further object of the invention is to provide a method for determining whether the vehicle was involved in a collision when the development of the safety device was initiated.

A further object of the present invention is to provide as small, lightweight and relatively inexpensive a device as possible.

These and several other advantages and features which characterize the invention are particularly pointed out in the appended claims which form a part of this application. For a better understanding of the invention and its advantages and objects, reference is made in the following detailed description to the accompanying drawings, in which a preferred embodiment of the invention is shown.

In the drawings, where the same reference numerals indicate corresponding parts in the various pictures,: Fig. 1 shows a view of a vehicle instrument panel and where airbags are mounted partly in the steering wheel of the vehicle and partly in its dashboard.

Fig. 2 a part of the airbag system where the gas generator has been broken out and removed.

Fig. 3 is a cross-sectional view of an inflator with the event sequence indicator located inside the sensor which in turn is located inside the inflator.

Fig. 4 is an outside view of a preferred embodiment of an event sequence indicator according to the invention.

Fig. 5 is a view of a preferred embodiment of the invention, showing a rest position.

Fig. 6 is a view of a preferred embodiment of the invention after the inflator has been activated in response to an accident.

The air cushion safety restriction system 7 shown in the drawings has a gas generator 8 mounted inside a housing 9 which is intended for a folded air cushion 12. Inside the gas generator 8 there is an event sequence indicator 10.

Referring to Fig. 4, a perspective view of the event sequence indicator 10 in idle mode is shown. The indicator consists of a tube 20 containing a ball 30 and a spring 40. The tube has a flange 50 for positioning the tube inside the gas generator (inflator) in an air cushion. 459 350 4 A preferred embodiment of the event sequence indicator consists of an aluminum tube 20 which is 25.4 mm long and has an inner diameter of approximately 3.2 mm and is closed at both ends. Inside the tube there is a 3.2 mm stainless steel ball 30 and a spring 40 which exerts a force on the ball which is greater than 1 g. The clearance between the ball and the tube is at least 1.18 x 10_4 mm, so that the tube can be manufactured using conventional manufacturing techniques. The tube is located on the inside of the inflator near the spark plug, which may also be located inside the sensor if the sensor is located in the inflator, in such a position that when the spark plug chamber is pressurized the tube is also exposed to the spark plug gas pressure.

The tube is so aligned in the inflator that its geometric axis lies substantially along the geometric axis of the vehicle. For example, if the inflator is located on the steering tube, the geometric axis of the tube is parallel to the geometric axis of the steering tube.

When, during an accident, the vehicle decelerates, the ball is caused to move forward in the tube during compression of the spring. As long as the vehicle (and thus the ball) is subjected to a deceleration force which is greater than the force exerted by the spring on the ball, the ball will be different from its original position. If the ignition cap is then ignited, the gas pressure in the ignition cap chamber will compress the thin-walled aluminum tube and trap the ball as shown in Fig. 6.

Thus, if the ignition cap is triggered unintentionally and the vehicle does not decelerate, the bullet will be caught in its original position. On the other hand, if the vehicle decelerates more than 3g and is therefore definitely in an accident, the bullet will be caught in a position different from the original position. This device, which only increases the cost of the airbag system by about 50 öre, solves the problem in a very simple way, which if it is to be done with an external device, ie outside the inflator, requires a separate sensor and some complicated electronics.

Of course, many other systems can be constructed that use other spring mass systems such as belts and rollers, pendulums, etc., and other environmental factors such as heat in the spark plug chamber can be used to capture the sensing mass. For example, if the mass was surrounded by plastic, the heat from the spark plug would deform the plastic to thereby trap the mass. Also, a pressure sensor with an electrical output such as a piezoelectric device, pressure switch or a temperature sensor could be placed in the spark plug chamber and used in combination with an accelerometer to detect the simultaneous presence of gas pressure or elevated temperature in the spark plug chamber and deceleration of the vehicle. . An electronic circuit utilizing a fuse or other recording means could, for example, detect if the vehicle decelerates at the time when the pressure or temperature first arises in the spark plug chamber. Although these devices are more complicated than the preferred embodiment of the invention, they provide a more accurate indication as to which event occurred first, the deceleration of the vehicle or the ignition of the ignition cap.

Accidents have been simulated where the described embodiment has been used. The clearance between the ball and the tubes in this device was 0.152 mm. The ball could move 15.9 mm before it was thrown back by the compressed spring. The spring gave an initial bias of 2.3 g, which increased as the ball moved into the tube to a maximum value of 8 g when the ball reached its distal position 15.9 mm away.

The simulations were done by first determining the time after which a typical passenger space sensor would have been triggered in each of the collisions. 3 ms were added to this trigger time to reach the approximate time when pressure arose in the (} \ ¶D LN (bl 10 6 firing cap). The simulation model was then run and the motion of the event sequence indicator ball was recorded at the above times. Table 1 below shows the results of the twenty simulations.The first column of the table indicates the test number; the second column gives a collision description; the third column indicates how far the ball moved at the time the pressure compressed the tube, and the fourth column indicates the result of the simulations when 15 ms was added The device would have given an incorrect indication in cases 4, 7, 14, 15 and 16 in the case where the inflation pressure was used instead of the ignition cap pressure.

TABLE 1 Collision log Distance (mm) 15 ms 1 64.2 km / h, Fmv # 1 6.66 0.154 Chevrolet Citation 1980 - 2 48.1 km / h, FMF # 1 7.59 0.433 Chevrolet Impala 1978 3 48.4 km / h, FMF # 1 7.32 0.368 Chevrolet Impala 1978 4 77.3 km / h, Fmv # 1 6.50 0.000 Chevrolet Citation 1980 5 56.4 km / h, Fmv # 1 6.20 0.389 Chevrolet Citation 1980 6 56.2 km / h, Fmf # 1 6.66 0.446 Volkswagen Rabbit 1979 7 56.0 km / h, Fmv # 1 6.81 0.044 Volkswagen Rabbit 1979 8 95.2 km / h, Fmf # 2 6.25 0.575 Ford Torino 1975 9 100.3 km / h, FMF # 1 5.97 0.341 Dodge Sportsman Van 1979 10 100.3 km / h, FMF # 2 6.93 0.199 Chevrolet Impala 1979 11 65.5 km / h, Fmv # 1 6.99 0.230 Plymouth Fury 1975 12 40.6 km / h, Fmv # 1 7.01 0.152 Dodge Sportsman Van 1979 13 72.6 km / h, Fmv # 1 6.66 0.228 Volvo 244 1975 20 25 30 35 7 TABLE 1 (continued) Collision course Distance (mm) 15 ms 14 40.3 km / h, Fmv # 1 6.45 0.055 Ford Van 1979 15 100.1 km / h, Fmf # 2 6.32 0.025 Honda Civic 1975 16 102.4 km / h, FMF # 1 7.49 0.015 Ford Torino 1979 17 101.9 km / h, FMF # 2 6.58 0.264 Chevrolet I mpala 1979 18 65.2 km / h, Fmv # 1 6.53 Ford Torino 1975 19 65.7 km / h, Fmv # 1 5.46 Honda Civic 1975 20 48.3 km / h, Fmv # 1 6.63 Ford Van 1979 Vehicle against wall Fmv Fmf FMF = Vehicle against vehicle ll Object against vehicle Only the cases where the airbag would have inflated were considered.

From the results shown above, the cases, it can be seen that in any case the bullet has moved more than 3.8 mm at the time when its movement as well as 280 are hindered by the compression of the tube and thus indicates that a collision was occurring.

In this description, the term spark plug has been used for the purpose of also including the primary inflator which initiates a pyrotechnic device. The term as such includes mechanically initiated inflaters as shown in U.S. Patent 4,580,810 and electric ignition caps used in electrically initiated airbag systems.

Thus, the above objects and advantages of the invention are clearly achieved. Although a preferred embodiment has been shown and described, it is to be understood that the invention is in no way intended to be limited thereby, but that its scope is determined by the appended claims.

Claims (12)

469 330 10 15 20 25 30 35 PATENT REQUIREMENTS An apparatus for indicating whether an airbag inflator for a vehicle was triggered due to an accident or not, the apparatus comprising: a) a container (20) closed at both ends and inserted into an airbag inflatable housing (9); wherein the container has a geometric axis that is substantially aligned with the geometric axis of the vehicle; b) an object (30) capable of moving along said container shaft in response to a deceleration of the vehicle beyond a predetermined level; c) a means (40) for exerting a force on the object to prevent the object from moving along the axle in the event that the vehicle does not decelerate beyond the predetermined level; and d) a means (20) for capturing the object (30) during its movement along said container shaft, said means preventing, in response to the influence of a gas causing inflation of the air cushion, the object to move further, characterized in that said container (20), object (30), force exerting means (40) and trapping means (20) are located in an ignition cap chamber present in said air cushion inflator housing (9) for actuating gases from the ignition cap when it is ignited. for generating the airbag inflation gas. Device according to claim 1, characterized in that the means for exerting a force is a spring (40). Device according to claim 1, characterized in that the predetermined level is 2.3 g. Device according to claim 1, characterized in that the means (20) for capturing the object (30) consists of the container, which is compressed in response to the gas pressure generated by the igniter cap gas inside the inflation housing before inflating the air cushion. 'x 10 15 20 25 30 35 469 330 9 Device according to claim 4, in that the container (20) is made of a characteristic thin metal. Device according to claim 5, characterized in that the metal is aluminum. Device according to claim 5, characterized in that the container (20) is made by the fact that the means (20) for capturing the object (30) is plastic. Device according to claim 1, n e t e c k n a d is made by the container, which collapses in response to the heat generated inside the inflator during the inflation of the air cushion. Device according to claims 1, 4, 5, 6 and 8, characterized in that the container (20) consists of a tube and that the object (30) consists of a ball. Device according to claim 9, characterized in that the ball (30) is made of stainless steel. 11. ll. Device according to claims 1, 4, 5, 6 and 8, characterized in that the object (30) consists of a pendulum. Device according to claims 1, 2, 5, 6, and 8, characterized in that the object (30) consists of a belt and a rolling device.