A safety device for a motor vehicle

Abstract: A safety device in a motor vehicle, the device comprising a gas generator (22), incorporating or associated with a sensor adapted to sense a side impact or a roll-over and to activate the gas generator, and an inflatable element (20) connected to the gas generator (22) to be inflated by gas from the gas generator, the inflatable element being made of fabric comprising a first layer to define the front part of the inflatable element, and a second layer to define the back part of the inflatable element, the inflatable element defining a single inflatable chamber (24) in which selected parts (25) of the first layer and the second layer are inter-connected to define points or lines where the front part and back part of the inflatable element (20) are secured together dividing the inflatable chamber (24) into a plurality of substantially parallel elongate cells, the inflatable element having a edge portion secured to part of the door fame (21) of the vehicle, the said part of the door frame being non-linear, there being a web (27) extending from the inflatable chamber (24) to the door frame, the inflatable element (20), when inflated, being positioned adjacent the door contained within the door fame (21), tension being applied to the inflatable element, on inflation thereof, by the distension of the inflatable chamber.

Description: THIS INVENTION relates to a safety device, and more particularly relates to a safety device in a motor vehicle such as a motor car. When a motor vehicle is involved in an accident there is a risk that the driver and passengers within the vehicle will be injured. It has been proposed to provide vehicles with safety devices to reduce the risk of such injury. Certain safety devices are intended to provide protection in the case of a side impact. US-A-5322322 discloses such a device. An inflatable tube is initially stored in a recess in the door frame above the door of the vehicle, and the ends of the tube are pivotally anchored to fixed points on the door frame. A sensor is provided to sense when an accident occurs, and to initiate inflation of the tube. As the tube inflates its length decreases, and it then extends linearly between the two fixed points on the door frame. The inflated tube provides some protection for the head of a person sitting in the vehicle. However, the tube is inflated to a substantial pressure, and thus the head of a person in the vehicle may tend to bounce off the tube. The tube may not cover the whole of the area of the window, and may not even cover the whole of the upper part of the window. There is thus a risk that the head of the person in the vehicle may move past the tube and pass through the window opening. If a car is rolling over this is very undesirable. DE-C-4 134 995 discloses a safety device according to the preamble of claim 1. This invention seeks to provide an improved safety device. According to this invention there is provided a safety device in a motor vehicle, the device comprising a gas generator, incorporating or associated with a sensor adapted to sense a side impact or a roll-over and to activate the gas generator, and an inflatable element connected to the gas generator to be inflated by gas from the gas generator, the inflatable element being made of fabric comprising a first layer to define the front part of the inflatable element, and a second layer to define the back part of the inflatable element, the inflatable element defining a single inflatable chamber in which selected parts of die first layer and die second layer are inter-connected to define points or lines where the front part and back part of the inflatable element are secured together dividing the inflatable chamber into a plurality of substantially parallel elongate cells, the inflatable element having an edge portion secured to part of the door frame of the vehicle, the said part of the door frame being non-linear, there being a web extending from the inflatable chamber to the door frame, the inflatable element, when inflated, being positioned adjacent the door contained within the door frame, tension being applied to the inflatable element, on inflation thereof, by the distension of the inflatable chamber. The inflatable element, when inflated, is thus located between the head of a person sitting in the vehicle and an adjacent door. Usually such a door is provided with a window and so the inflated element provides protection from breaking glass from the window, and also prevents the head of the person in the vehicle from striking the window, or from being thrown out through the window, as can happen, particularly with roll-over accidents. Preferably the safety device is usually initially stored in a recess provided in the door frame. Preferably the inflatable element is made of interwoven fabric layers, the said selected parts of the first layer and the second layer being interwoven. There is internal venting between the cells as this may reduce undesirable bounce that might occur if the cells were discrete and not vented to each other. Thus if the head of the person in the vehicle impacts with the inflated element the pressure of gas within the whole element, or at least a substantial part of the element will rise, thus giving a "soft" impact. If each cell were sealed with no venting of this type, there would be a risk of severe rebound. The inflatable element may be formed of a fabric which has a single layer weight of less than 300g/m 2 , such as a weight of 175 g/m 2 . Preferably when the inflatable element is inflated the pressure of gas is approximately 3 bar. Preferably the inflatable element, when inflated, extends past the B-Post of the vehicle, to provide protection for the head of the driver. If the head of the driver should impact with the B-Post in an accident the consequences could be fatal. Separate means may be provided to apply tension to part of the inflatable element when it is inflated, such as a piston and cylinder, adapted to be moved by gas from a gas generator when the inflatable element is inflated, to apply tension to one edge of the inflatable element, to hold the inflated element in a desired position. In one embodiment the inflatable element is provided with means adapted to move from an initial position to a further position on inflation of the inflatable element, an arrangement being provided to retain the said means in the said further position. Thus a slider maybe provided adapted to slide along a ratchet, and to be retained by the ratchet when it has moved to a further position. In order that the invention may be more 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 1 is a side view of part of the interior of a motor vehicle illustrating a safety device in accordance with the invention in the operative state, FIGURE 2 is a sectional view of part of the embodiment of Figure 1, and FIGURE 3 is a view of part of Figure 1 showing an additional component of the safety device. Figures 1 to 3 illustrate an embodiment of the invention. In this embodiment an inflatable element 20 is provided which is initially stored in a recess provided in the door frame 21 of a motor vehicle. A gas generator 22 is provided, which incorporates or is associated with a sensor or detector which activates the gas generator at an appropriate time. The gas generator is connected by a duct 23 to an inflatable chamber 24 of the inflatable element 20. The gas generator 22 is located in the door frame 21 of the vehicle, but alternatively could be positioned in the B-Post. The inflatable chamber 24 is formed within the inflatable element 20 from two layers of fabric, with the front layer and the back layer of the fabric being woven together at selected points 25. The selected points 25 are located in vertically extending lines and serve to divide the inflatable part 24 into a plurality of vertical parallel cells. The spaces between the selected points 25 permit internal venting between adjacent chambers. The inflatable chamber 24 of the inflatable element 20 is adapted to be located adjacent the head of an occupant of the motor vehicle, and, towards the rear of the inflatable element, wherein the position illustrated in Figure 1, the inflatable chamber of the inflatable element extends from the top to the bottom of the inflatable element in a rear region and subsequently, the upper edge of the inflatable part extends downwardly towards the lower edge of the inflatable element, in a sense directed towards the A-Post 26. The remaining part of the inflatable element comprises a web or sheet 27 which extends from the chamber 24 to the part of the door frame 21 above the door and the A-Post. The web or sheet 27 is thus secured to parts of the door frame that are non-linear. It is to be appreciated, therefore, that in this embodiment of the invention die upper edge of the inflatable element is of non-linear form and is of the same configuration as the non-linear part of the door frame which extends forwardly from the B-Post and which incorporates the A-Post. The upper edge of the inflatable element, or at least a substantial part of that upper edge, is securely fixed to the upper part of the door frame, thus minimising any risk of the head of the occupant emerging from the body shell between the upper edge of the curtain and the upper part of the door frame. Referring to Figure 2 the edge of the sheet 27 that is secured to the door frame 21 may terminate with a bead 28 that is received within a slot 29 formed in the door frame, the mouth of die slot being narrower than the base so that the bead 28 can slide axially within the slot, but cannot escape from the slot. A cable 30 is connected to the end of the bead, as can be seen in Figure 3, the cable being connected to a tensioning device 31. The tensioning device may comprise a piston in a cylinder associated with a gas generator to generate gas which moves the piston within the cylinder to apply tension to the cable 30 and thus to the bead 28. A ratchet or the like may hold the piston in place when it has been moved by the gas. The gas generator that supplies gas to the piston may be the gas generator 22 or may be a separate gas generator that is triggered simultaneously with the main gas generator. When an accident occurs the gas generator 22 generates gas which inflates the inflatable element 20. The gas may be at a pressure of about 3 bar. Thus, the inflatable element 20 moves from its stored position to the operative position shown in Figure 1, and tension is applied to the inflatable element 20 by the distension of the chamber 24, and by the tension applied to the bead 28. The inflated element 20 is thus held firmly in position to provide protection for the head of the person sitting in the motor vehicle. The weight of the fabric should be kept to be as low as possible, so that if the inflatable element should impact with the head of the person in the vehicle as the inflatable element is inflated no harm will be done. It is thought that a material having a weight of less than 300 g/m 2 , such as 175 g/m 2 may be used. Whilst in the described embodiments of the invention the inflatable element has been described as being made utilising a technique in which two layers of fabric are interwoven to define points or lines where the front layer and the rear layer are interwoven, it would be possible to form embodiments of the invention utilising two discrete layers of fabric which are inter-connected by stitching. A technique for making an inflatable element of interwoven fabric is described in more detail in International Patent Publication WO 90/09295. In the present specification "comprise" means "includes or consists of" and "comprising" means "including or consisting of'.

Claims: A safety device in a motor vehicle, the device comprising a gas generator (22), incorporating or associated with a sensor adapted to sense a side impact or a roll-over and to activate the gas generator, and an inflatable element (20) connected to the gas generator (22) to be inflated by gas from the gas generator, the inflatable element being made of fabric comprising a first layer to define the front part of the inflatable element, and a second layer to define the back part of the inflatable element, the inflatable element defining a single inflatable chamber (24), the inflatable element having an edge portion secured to part of the door frame (21) of the vehicle, the inflatable element (20), when inflated, being positioned adjacent the door contained within the door frame (21), characterised in that selected parts (25) of the first layer and the second layer are inter-connected to define points or lines where the front part and back part of the inflatable element (20) are secured together dividing the inflatable chamber (24) into a plurality of substantially vertical parallel elongate cells, the said part of the door frame is non-linear, there being a web (27) extending from the inflatable chamber (24) to the door frame, tension being applied to the inflatable element, on inflation thereof, by the distension of the inflatable chamber. A safety device according to Claim 1 wherein the inflatable element (20) is initially stored in a recess provided in the door frame A safety device according to Claim 1 or 2 wherein the inflatable element (20) is made of interwoven fabric layers, the said selected parts (25) of the first layer and the second layer being interwoven. A safety device according to Claim 3 where there is internal venting between the cells. A safety device according to any one of the preceding Claims wherein the inflatable element (20) is made of a fabric having a single layer weight of less than 300/m 2 . A safety device according to any one of the preceding Claims wherein when inflated, the pressure in the inflatable element (20) is approximately 3 bar. A safety device according to any one of the preceding Claims wherein the inflatable element (20), when inflated, extends past the B-Post of the vehicle. A safety device according to any one of the preceding Claims incorporating separate means (30, 31) to apply tension to part of the inflatable element (20) when it is inflated. A safety device according to any one of the preceding Claims wherein the inflatable element (20) is provided with means (30) adapted to move from an initial position to a further position on inflation of the inflatable element, an arrangement being provided to retain the said means in the said further position.

Inventors: ANDERSSON STURE, FLORBERGER LARS-ERIK, HALAND YNGVE, SVENSSON I JORGEN, VALKENBURG SIMON, ANDERSSON, STURE, FLORBERGER, LARS-ERIK, HALAND, YNGVE, SVENSSON, I. JORGEN, VALKENBURG, SIMON
Applicants: AUTOLIV DEV, AUTOLIV DEVELOPMENT AB
Application year: 1996
Main classification: B60R21
IPC codes: B60R21, B60R22