WO1994001734A1

WO1994001734A1 - Shock pulse coupling arrangement

Info

Publication number: WO1994001734A1
Application number: PCT/SE1993/000614
Authority: WO
Inventors: Torsten Persson; Staffan Carlsson
Original assignee: Autoliv Development Ab
Priority date: 1992-07-06
Filing date: 1993-07-06
Publication date: 1994-01-20
Also published as: SE9202079D0; DE4393230T1

Abstract

A shock pulse coupling arrangement is disclosed for coupling a shock pulse between two elements (1, 2) which are moveable relative to each other. One element (1) comprises a housing (5) containing a pyrotechnic charge (9). The second element (2) comprises a housing (11) containing a receptor charge (14). The elements are positioned relative to each other so that the pyrotechnic charge (9) of the first element (1) is immediately adjacent the receptor charge (14) of the second element. When the pyrotechnic charge (9) of the first element is initiated, for example by a shock pulse in a shock tube (8), the receptor charge (14) of the second element (2) is initiated and a pulse is passed down a second shock tube (13).

Description

Shock Pulse Coupling Arrangement

The present invention relates to a shock pulse coupling arrangement and in particular relates to a coupling arrangement for coupling a shock pulse between two components which move relative to one another.

It is known to utilise a shock pulse to ignite a pyrotechnic device. In particular, it is known to use a shock pulse to initiate activation of a pyrotechnic gas generator associated with an air bag fitted in a motor vehicle, the air bag being adapted to be inflated to provide protection for a driver or passenger in the vehicle in the event that an accident should arise. In such an application, the shock pulse is generated by a crash sensor. The shock pulse may be transmitted from the sensor to the gas generator present in the air bag through a shock tube. A typical shock tube is that sold under the Trade Mark NONEL.

A problem can arise when a shock pulse has to be coupled from a first component to a second component which moves relative to the first component. For example, if an air bag is mounted in a component such as the hub of a steering wheel, and a crash sensor is mounted at a fixed point on the chassis of the motor vehicle, some arrangement must be provided to transmit the shock to the gas generator in the airbag. Although a length of shock tube can be wound in a spiral fashion round at the axis of the steering column, with one end being fixed in position and the other end being fi =≥d to the hub of the steering wheel, this has certain disadvantages. On the one hand, a relatively long length of shock tube must be provided, which leads to an increased delay between the crash sensor being activated and the air bag being inflated. On the other hand, the shock tube will describe a radius which may influence the transmission speed for the shock pulse. Also, the repeated bending over the shock tube during rotation of the steering wheel may damage the shock tube, and also the repeated movement may loosen the shock tube and cause the shock tube to become detached from the gas generator.

Similar difficulties exist if, for example, a crash sensor is mounted in a component, such as door, whilst the air bag associated with the crash sensor is mounted in a fixed position within a motor vehicle, since then a length of shock tube must be provided which extends between the door and the chassis of the vehicle. This length of shock tube will be subjected to mechanical action as the door opens and closes.

A similar situation will exist where a crash sensor is mounted in a fixed position on a motor vehicle and the air bag associated with the sensor is mounted in a seat, which seat is adjustably mounted in the vehicle.

The present invention seeks to provide a shock pulse coupling arrange for coupling a shock pulse between two components which move relative to each other.

According to this invention, there is provided a shock pulse coupling arrangement for coupling a shock pulse between two elements, the elements being moveable relative to each other, one element comprising a housing containing a pyrotechnic charge, the second element comprising a housing containing a receptor charge, the elements being positioned or positionable relative to each other so that the pyrotechnic charge of the first element is immediately adjacent the receptor charge of the second element, the arrangement being such that whenever the pyrotechnic charge of the first element is initiated, the receptor charge of the second element is initiated.

Preferably, the first element comprises a housing defining a chamber receiving the pyrotechnic charge, the chamber being closed by a diaphragm, the diaphragm being located adjacent the second element.

Conveniently, the first element is connected to a shock tube which is in communication with the pyrotechnic charge.

Advantageously, the second element comprises a housing defining a chamber receiving a receptor pyrotechnic charge, that cavity being closed by a diaphragm, the diaphragm being located adjacent the first element.

Preferably, the second element comprises a housing defining a cavity receiving, as the receptor charge, a percussion primer, the cavity being located adjacent the first element.

Advantageously, the cavity receiving the percussion primer is sealed by a pressure absorbing diaphragm adapted to act against the anvil of the percussion primer.

Conveniently, the receptor charge is operatively connected to a shock tube.

Preferably, one element is adapted to rotate freely relative to the other element.

Advantageously, the coupling arrangement forms part of the coupling between a sensor mounted at a fixed position on a motor vehicle and an air bag gas generator located in the steering wheel of the vehicle.

Conveniently, one element is mounted in a door on a motor vehicle and the other element is mounted in a part of the door frame.

Advantageously, one element is adapted to move linearly relative to the other element.

Preferably, the second element defines a receptor charge which is of elongate form.

Advantageously, the second element defines a plurality of receptor charges at spaced apart position.

Preferably, each receptor charge is associated with a separate shock tube, the shock tubes being operatively interconnected.

Advantageously, one element is fixed in position of the chassis of the motor vehicle and the other element is mounted on a seat which is adjustable positionable within the motor vehicle.

In order that the invention may be readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which

Figure l is a sectional view of one embodiment of the invention comprising a shock pulse coupling arrangement adapted for use in coupling a shock pulse between two components which rotate relative to each other, the arrangement comprising two co-operating elements,

Figure 2 is a vertical sectional view of an alternative form of element that can be substituted for one of the elements of the arrangement of Figure 1;

Figure 3 is a sectional view through part of a door and an associated "B" post illustrating two elements forming another shock pulse coupling arrangement;

Figure 4 is a sectional view illustrating two elements forming another type of shock pulse coupling arrangement in which one element is intended to move in a linear manner adjacent the other element;

Figure 5 is a sectional view illustrating a further form of shock pulse coupling arrangement where one element is intended to move in a linear manner adjacent the other element; Referring initially to Figure 1, a shock pulse coupling arrangement is illustrated comprising two elements 1,2, one element 2 being adapted to rotate, as indicated by the arrow 3, about an axis 4.

The first element 1, comprises a substantially cylindrical housing 5 which is securely mounted in position by a support 6. The cylindrical housing 5 defines an axial bore 7. One end of the bore receives one end of a shock tube 8, such as, for example, a shock tube of the type sold under the Trade Mark NONEL. The operative part of the shock tube 8 is in operative communication with a small pyrotechnic charge 9 which is located in a position in an enlarged part of the bore 7, the enlarged part of the bore 7 being located at the end of the cylindrical housing 5, but being closed by a sealing diaphragm 10. The diaphragm 10 may be of metal or plastic.

The second element 2 comprises a substantially cylindrical housing 11. The housing 11 defines an axially extending through bore 12, one end of which accommodates the terminal part of a shock tube 13, the shock tube being of the type sold under the Trade Mark NONEL. A pyrotechnic receptor charge 14 is received within an enlarged part of the bore 12, which is located at the lower end of the cylindrical housing 11, but which is closed by means of a sealing diaphragm 15, which may be of metal or plastic.

A small gap 16 exists between the sealing diaphragm

10 and the sealing diaphragm 15.

Part 17 of the housing 11 projects beyond the location of the diaphragm 15 to form a shroud which partially encircles the end of the housing 5 carrying the diaphragm 10.

The housing 11 is mounted for rotation about the axis 4 by means of a bearing 18.

It is to be appreciated that the element 1 and the element 2 are totally separate, and the element 2 can thus be mounted in a component, such as a steering wheel, which can be freely rotatable relative to a component which supports the fixed element 1.

If a shock pulse is transmitted along the shock tube 8 associated with the housing 5, the pyrotechnic charge 9 will be ignited, rupturing the diaphragm 10 of the pulse from the pyrotechnic charge 9 will pass across the relatively small gap 15, and through the sealing diaphragm 15 to initiate the receptor pyrotechnical charge 14, which in turn initiates a shock pulse which travels along the shock tube 13.

It is to be appreciated that whilst the embodiment described above incorporates two elements which are each connected to a shock tube, one element could be connected directly to a shock pulse source, such as a pyrotechnic crash detector. Alternatively, the other element might be connected directly to an item triggered by a shock pulse, such as a gas generator present in an air bag. Thus, whilst it is most likely, that a coupling arrangement will be located between two shock tubes which are to be operatively interconnected, the coupling arrangement could find other applications. Figure 2 illustrates an element 20 that can be utilised instead of the element 2 of Figure l. The element 20 comprises a housing 21 defining a through-bore 22, which receives the terminal portion of a shock tube 23. An enlarged portion of the through-bore 22 contains as a receptor charge, a commercial percussion primer 24. The enlarged portion 22 of the through bore has an end which is closed by a pressure absorbing diaphragm 25 adapted to act against the anvil in the primer 24 when the coupling arrangement is operative. The diaphragm 25 is intended to be located adjacent the diaphragm 10 of an element corresponding to the first element 1 of Figure 1.

It can be seen that the housing 21 is provided with a portion 26 extending forwardly of the plane defined by the diaphragm 25, adapted to enshroud part of the housing 5 of the element 1.

It is thus to be appreciated that the element 20 may be used in precisely the same manner as the element 2 of the Figure 1 embodiment.

Whilst Figures 1 and 2 relate to arrangements where one element is adapted to rotate relative to the other element, in the embodiment of figure shock, the shock pulse coupling arrangement comprises one element 30 which is mounted in a door 31 of a motor vehicle and a second element 32 which is mounted in the "B" post 33 of the motor vehicle which forms part of the door frame for the door. The element 30 comprises a housing 34 which is effectively of the same design as the housing 5 of Figure 1. The housing 34 has a central bore 35 with an enlarged terminal portion containing a pyrotechnic charge 36 and sealed by a diaphragm 37, there being a shock tube 38 associated with the housing 34.

The element 32 comprises a housing 39 which effectively is of the same design as the housing 11 of the embodiment of Figure 1. The housing 39 defines a through bore 30 having an enlarged terminal portion which contains a receptor pyrotechnic charge 41, and which is sealed by a diaphragm 42, there being a shock tube 43 associated with the housing 39.

It can be seen that the element 30 and the element 32 are so positioned that when the door 31 is closed the diaphragm 37 is spaced from but located immediately adjacent the diaphragm 42. Thus, this coupling arrangement will operate in the same way as the coupling arrangement of Figure l.

Turning now to Figure 3, a further type of coupling arrangement is illustrated comprising a first element 45 and a second element 46. The first element 45 comprises a housing 46 of the same design as the housing 5 of the element 1 of Figure 1, the housing 46 containing a pyrotechnic charge 47 located in an enlarged part of an axial through bore 48 which is sealed by a diaphragm 49, the housing 46 being associated with a shock tube 50.

The element 46 comprises a housing 51 which is of a similar design to the housing 11 of Figure 1, but of rather a different configuration, in that the housing defines an elongate channel 52 which contains a pyrotechnic charge 53 and which is sealed by means of a diaphragm 54, that channel being inoperative communication with a shock tube 55.

The diaphragm 49 is located adjacent the diaphragm 54.

It is intended that there is to be relative linear movement between the element 45 and the element 46 in a transverse direction, as indicated schematically by the arrows 56,57 Thus, for example, the element 45 may be fixed in position on the chassis of a motor vehicle and the element 46 may be mounted on a seat of a motor vehicle, which seat is intended to be adjustable in position axially of the motor vehicle. Thus, the seat can move generally in a direction indicated by the arrows 56 and 57.

It is to be appreciated that when the seat has been adjusted, the diaphragm 49 wil be located at a position spaced from but immediately adjacent part of the diaphragm 54. It will thus be understood that when a shock pulse is present in the shock tube 50 the receptor pyrotechnic charge 47 will be initiated, causing the diaphragm 49 to rupture, the resultant pulse will pass across the gap between the diaphragm 49 and the diaphragm 54, passing through the diaphragm 54 and activating the pyrotechnic charge 53, thus initiating a shock pulse in the shock tube 55. Figure 5 illustrates a further embodiment of the invention which again may be of use in a situation where there is to be linear movement between the elements, for example in a situation involving a seat adjustably positioned within a motor vehicle.

In the embodiment of Figure 5, a first element 60 comprises a housing 61 of the same design of the housing 5 of the embodiment of Figure 1, having a pyrotechnic charge

62 formed in an enlarged terminal portion of a through bore

63 which is closed by means of a diaphragm 64, there being a shock tube 65 associated with the housing 61 and in operative communication with the pyrotechnic charge 62.

The second element 66 of the coupling arrangement comprises a housing 67 which defines a plurality of bores 68, 68a, etc., each defining an enlarged end portion receiving a respective receptor pyrotechnic charge 69, 69a, etc., each end portion being sealed by a diaphragm 70, 70a, etc.

Each bore is associated with a respective shock tube 71, 71a, etc.

The shock tubes 71, 71a, etc., are all interconnected.

The pyrotechnic receptor charges 69, 69a, etc., are all evenly spaced apart. When a seat in a motor vehicle is adjusted, the seat may be adjusted between a plurality of predetermined positions which are substantially evenly spaced apart. Usually the seat carries a spring biased plunger adapted to be engaged in one of a plurality of evenly spaced apart recesses or apertures formed in the track on which the seat moves.

It is envisaged, therefore, that the element 66 may be mounted on a seat in a movable generally as indicated by the arrows 72, 73 whilst the element 60 will be fixed in position. Whenever the seat has been adjusted to one of its predetermined position, the diaphragm 64 will be located immediately adjacent a diaphragm 70, 70a, etc present on the housing 67. Thus, when a shock pulse is present in the shock tube 65, initiating the pyrotechnic charge 62 and rupturing the diaphragms 64, the resultant shock pulse will pass through the adjacent diaphragm 70, 70a, etc of the housing 67, initiating the pyrotechnic charge 69, 69a, etc and thus causing a pulse to travel down the associated shock tube 71, 71a, etc.

Claims

1. A shock pulse coupling arrangement for coupling a shock pulse between two elements, the elements being moveable relative to each other, one element comprising a housing containing a pyrotechnic charge, the second element comprising a housing containing a receptor charge, the elements being positioned or positionable relative to each other so that the pyrotechnic charge of the first element is immediately adjacent the receptor charge of the second element, the arrangement being such that whenever the pyrotechnic charge of the first element is initiated, the receptor charge of the second element is initiated.

2. A shock pulse coupling arrangement according to Claim 1, wherein the first element comprises a housing defining a chamber receiving the pyrotechnic charge, the chamber being closed by a diaphragm, the diaphragm being located adjacent the second element.

3. A shock pulse coupling arrangement according to Claim 1 wherein the first element is connected to a shock tube which is in communication with the pyrotechnic charge.

4. A shock pulse coupling arrangement according to any one of the preceding claims wherein the second element comprises a housing defining a chamber receiving a receptor pyrotechnic charge, that cavity being closed by a diaphragm, the diaphragm being located adjacent the first element.

5. A shock pulse coupling arrangement according to anyone of Claims 1 to 3, wherein the second element comprises a housing defining a cavity receiving, as the receptor charge, a percussion primer, the cavity being located adjacent the first element.

6. A shock pulse coupling arrangement according to Claim 5, wherein the cavity receiving the percussion primer is sealed by a pressure absorbing diaphragm adapted to act against the anvil of the percussion primer.

7. A shock pulse coupling arrangement according to any one of the preceding claims wherein the receptor charge is operatively connected to a shock tube.

8. A shock pulse coupling arrangement according to any one of the preceding claims, wherein one element is adapted to rotate freely relative to the other element.

9. A shock pulse coupling arrangement according to Claim 8 wherein the coupling arrangement forms part of the coupling between a sensor mounted at a fixed position on a motor vehicle and an air bag gas generator located in the steering wheel of the vehicle.

10. A shock pulse coupling arrangement according to any one of Claims 1 to 7 wherein one element is mounted in a door on a motor vehicle and the other element is mounted in a part of the door frame.

11. A shock pulse coupling arrangement according to any one of Claims 1 to 7 when one element is adapted to move linearly relative to the other element.

12. A shock pulse coupling arrangement according to Claim 11 wherein the second element defines a receptor charge which is of elongate form.

13. A shock pulse coupling arrangement according to claim 11 when the second element defines a plurality of receptor charges at spaced apart position.

14. A shock pulse coupling arrangement according to claim 13 wherein each receptor charge is associated with a separate shock tube, the shock tubes being operatively interconnected.

15. A shock pulse coupling arrangement according to any one of claims 11 to 14 wherein one element is fixed in position of the chassis of the motor vehicle and the other element is mounted on a seat which is adjustable positionable within the motor vehicle.

16. A shock pulse coupling arrangement substantially as herein described with reference to and as shown in Figure

1 of the accompanying drawings.

17. A shock pulse coupling arrangement substantially as herein described with reference to and as shown in Figure

2 of the accompanying drawings.

18. A shock pulse coupling arrangement substantially and as shown in reference to Figure 3 of the accompanying drawings.

19. A shock pulse coupling arrangement substantially as herein described with reference to and as shown in Figure

4 of the accompanying drawings.

20. A shock pulse coupling arrangement substantially as herein described with reference to and as shown in Figure

5 of the accompanying drawings.