FR2729450A1 - Flexible valve for supple reservoir operated by pyrotechnic action - Google Patents

Abstract

The valve is made from a flexible material which is resistant to pressure but is capable of tearing, such as an elastomer, thermoplastic, rubber, polyurethane or silicone, and is actuated by a pyrotechnic compound to split along prepd. tear lines (12) ending in recesses which limit the tears. The valve is fitted to an inflatable reservoir (1) by adhesive, welding or ultrasound, or by vulcanisation, depending on the materials used, and the pyrotechnic compound (8) is pref. covered by a cap (10) to protect it from external aggressive action or to protect the environment or a vehicle driver from the pyrotechnic effects.

Description

 The controlled emptying of flexible or rigid tanks is essentially done by opening rigid valves controlled mechanically, pneumatically, electrically or hydraulically.

 These systems are relatively bulky and heavy mainly when they equip flexible structures deployable under the effect of gas generator.

 The present invention aims to overcome this major drawback.

 The valve made of flexible material is fixed directly to the flexible structure, it has imprints of preferential tearing orientation. The valve is fitted, at the footprint node, with a pyrotechnic component electrically connected to the control module. At the selected time, the operation of the pyrotechnic component is controlled, which, by drilling or cutting, initiates the tearing of the valve along the preferred axes. This tearing is created by the effect of the internal overpressure of the reservoir on the valve.

 The valve, object of the invention, is flat and very light.

It is particularly suitable for equipping inflatable flexible structures and mainly those which are subject to rapid deployment under the effect of gases such as automobile airbags.

 The valve, object of the invention, has only a reduced volume, a very small thickness and great flexibility, which does not interfere with the folding of the reservoir. At the time of deployment of the bag, the lightness of the valve, object of the invention, does not create a point of accumulation of stress due to the setting in motion or the absorption of kinetic energy at the end of deployment.

 The pyrotechnic operation of the initiation of tearing is very rapid, which facilitates control and improves the performance of the valve.

 Other characteristics and advantages of the invention will emerge from the detailed description which follows with reference to the appended drawings which represent, by way of nonlimiting examples, preferred embodiments.

 Figure 1 is a sectional view of a flexible tank equipped with the inflation and connection interface and the flexible valve tearable by pyrotechnic initiation.

 Figure 2 is a sectional view of an automotive safety air bag equipped with the flexible valve tearable by pyrotechnic initiation.

 Figure 3 is a front view of the flexible valve tearable by pyrotechnic initiation corresponding to Figure 1, it is said to petalization.

 Figure 4 is a front view of a variant of flexible valve tearable by pyrotechnic initiation, it is said to tilt tab.

 According to Figures 1 and 3, the inflatable flexible tank (1) is equipped with a gas inlet (2) and a connecting piece (3). The tank is preferably secured by bolts (4).

 The reservoir (1) has an orifice (5) limited by the edge (6). The valve (7) made of flexible material is assembled with the reservoir (1) preferably by bonding, welding or ultrasound, vulcanization, depending on the nature of the respective materials of the valve and of the reservoir. The valve is according to the invention, preferably made of thermoplastic elastomer, rubber, silicone, polyurethane or a thermoformed thermoplastic film. However, without departing from the invention, other materials can be used.

 According to the invention, to favor the controlled opening of the valve, imprints of preferential tearing orientation (12) will generally be produced; to limit the propagation of the tearing, these imprints will preferably be terminated by cells (13) for dispersing the tearing stresses. Tearing along the imprints (12) releases the tilting of the petals (14).

 The electrical connection (9) between the control module and the pyrotechnic component (8) for initiating the tearing will preferably consist of a flexible flat circuit integrated or not in a protective tongue (15) extending the valve.

The pyrotechnic component (8) is preferably protected by a cover (10) integrated or not in the valve (7). This protection has a double function. protect the component from external aggressions and protect the environment, for example the car driver from the pyrotechnic effect.

 Without departing from the invention, other types of electrical connection can be used, such as wires, likewise, without departing from the invention, it is possible to integrate into the pyrotechnic component (8) the receiving element of a command. wirelessly and the source of energy needed to turn it on.

 The flexible valve tearable by pyrotechnic initiation can, according to the invention, have other geometric shapes than circular and other types of openings than by petalization.

 According to Figure 4, it can also preferably have a square or rectangular geometry and an opening by tilting tongue (17).

 The flexible valve that can be torn apart by pyrotechnic initiation is preferably suitable for automobile safety air bags deployed by generation of pyrotechnic gas.

 In this case, according to Figure 2, the gas generator (14) replaces the gas inlet (2). The rest of the construction preferably remains similar to that of the flexible tank represented by FIG. 1.

 However, it is also possible, without departing from the invention, to place the tear-away flexible valve (7) next to the generator above the connection plate (3) which will then be pierced with an orifice to allow on the one hand, the free opening of the petals (14), the tilting tongue (17) or any other component of the valve, and on the other hand, the free passage of gases expelled from the automobile safety air bag.

 Without departing from the invention, this construction variant can be used in applications other than automobile safety.

 Without departing from the invention, these flexible valves which can be torn apart by pyrotechnic initiation may also be fitted with flexible tanks filled with liquid or solid particles, as well as rigid or hybric tanks filled with gas, liquid or solid particles.

Claims (5)

1) Device intended to equip flexible tanks or  rigid to achieve a controlled emptying in that it is  consisting of a flexible valve that can be torn by initiation  pyrotechnic. 2) Flexible valve tearable by pyrotechnic initiation according to  claim 1 and characterized by the presence  prints of preferential orientation of the tearing. 3) Flexible valve tearable by pyrotechnic initiation according to  claims 1 and 2 and characterized by the presence of  pyrotechnic component at the node of the orientation prints  preferential tearing. 4) Flexible valve tearable by pyrotechnic initiation according to  one of claims 1 to 3, characterized in that it  is made of a flexible material resistant to  overpressure but tearable such as elastomer,  thermoplastic, rubber, polyurethane, silicone and film  thermoplastic. 5) Flexible valve tearable by pyrotechnic initiation according to  one of claims 1 to 4, characterized in that the  electrical connection of the pyrotechnic component is integrated and  protected in a tab extending the valve.