A safety device for a motor vehicle

Abstract: A safety device for a motor vehicle comprises an inflatable element which is initially stored in position in a recess in the door frame, but when inflated extends between the head of a person sitting in the motor vehicle and the door, or a window in the door. The device provides protection in a side impact or roll-over situation.

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, which has the features defined in the preamble of claim 1. 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. 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 having an edge portion secured to part of the door frame of the vehicle, the said part of the door frame being non-linear, the inflatable element, when inflated, being positioned adjacent the door contained within the door frame, wherein the inflatable element is 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, selected parts of the first layer and the second layer being interwoven so that the front part and back part of the inflatable element are secured together, the inflatable element incorporating a plurality of substantially parallel elongated cells, the cells being spaced apart from each other by relatively wide regions of fabric between the cells that'are inter-woven and being substantially vertical, the arrangement being such that as the inflatable element inflates the length of the lower edge of the inflatable element is reduced and the lower edge of the inflatable element extends substantially tightly between two anchoring points on the vehicle. 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 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. The cells may be substantially cylindrical when inflated. At least some of the cells may be of conical form when inflated. The inflatable element is formed of a fabric with parts of the fabric being interwoven to form said cell or cells. The fabric may have a single layer weight of less than 300g/m 2 , such as a weight of 175g/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. In one embodiment the inflatable element incorporates a strap to connect part of the inflatable element to the door frame. The strap is tight when the inflatable element is inflated. In one embodiment the inflatable element is provided with a member mounted in the inflatable element adapted to move from an initial position to a further position on inflation of the inflatable element, a retaining arrangement being provided on the body of the motor vehicle to retain the said member in the said further position. Thus a slider may be provided adapted to slide along a ratchet, and to be retained by the ratchet when it has moved to a further position. In one embodiment of the invention the first and second layers of fabric are secured together at selected points, the points being located in vertically extending lines that divide an inflatable part of the inflatable element into said parallel cells. 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 the interior of a motor vehicle illustrating a safety device in accordance with the invention in an operative state, FIGURE 2 is a side view of the interior of a motor vehicle provided with another form of safety device in accordance with the invention, before the safety device moves to the operative state, FIGURE 3 illustrates the vehicle of Figure 2 when the safety device is in the operative state, FIGURE 4 is a sectional view of part of safety device as shown in Figure 1 or in Figures 2 and 3, and FIGURE 5 is a view of part of an alternative inflatable element. Referring initially to Figure 1 a safety device is illustrated which is intended to provide protection for a person 1 sitting in a seat 2 in the vehicle. In any accident in which the vehicle is decelerated the person will tend to move forwardly towards the steering wheel 3, but will be restrained by a conventional seat belt or airbag. In the case of a side impact or roll-over, there is a risk that the head of the person 1 will strike the window in the door beside the person, or strike the B-post. There is also a risk that if, as most commonly happens, the glass in the window should break, the head of the person 1 may be thrown out of the window, especially in the case of roll-over. The safety device shown in the operative state in Figure 1 is initially retained in a recess provided in the door frame 4 located above the door of the vehicle. The recess extends over more than simply a linear portion of the door frame so that the two ends of the recess are not in alignment with the main part of the recess. The safety device comprises a gas generator 5, which is adapted to generate gas, such as cold gas. The gas generator incorporates, or is associated with, a sensor which senses a side impact and/or a roll-over situation to activate the gas generator at an appropriate instant. The gas generator is connected by a hose 6 to a duct 7. The duct 7 forms part of an inflatable element The inflatable element incorporates a plurality of parallel substantially vertical, substantially cylindrical cells 8. The inflatable element is made of interwoven fabric. Such a fabric comprises a first layer that defines the front of the inflatable element - that is to say the part that is visible in Figure 1 - and a second layer that defines the back part - that is to say the part that is adjacent the window in Figure 1 - selected parts of the first layer and the second layer being interwoven so that the front part and the back part of the inflatable element are secured together. A technique for making an inflatable element of inter-woven fabric is described in more detail in International Patent Publication WO90/09295. A webbing strap 9 that forms part of the inflatable element extends from the end of the inflatable element near the duct 7 which is connected to the hose 6 to an anchoring point 10 on the door frame 4. The edge of the duct 7 between the points 11, adjacent the top of the B-post 12, and 13, at the lower part of the A-post, in the region of the dashboard 14, is fixed securely to the door frame 4. Consequently, it is to be understood that the upper edge of the inflatable element has a non-linear configuration which conforms with the non-linear configuration of the upper part of the door frame 4. A substantial part, in fact virtually all, of the upper edge of the inflatable element is secured to the upper part of the door frame. When an accident such as side impact occurs the gas generator generates cold gas which passes through the hose 6 to the duct 7, and then inflates the cells 8. The inflatable element thus moves from its initial stored position within the recess in the door frame to the operative position shown in Figure 1. The inflatable element then extends downwardly from the top of the door frame to form a flat structure located between the head of the person 1 and the adjacent window. As the cylindrical cells inflate the length of the lower edge 15 of the inflatable element is reduced, and thus the lower edge, together with the webbing strap 9 extend substantially tightly from the point 10 to the point 13. It is to be noted that the part of the door frame 4 between the points 10 and 13 is not linear, and defines, with the linear lower edge of the inflated element, a triangular area which is covered by the inflated element. The lower edge of the inflated element decreases by about 10% between the uninflated state and the inflated state. The inflated element is fully inflated within about 15ms. The total thickness of the inflated element, when inflated is approximately 30 - 40 mm. The seams of interweaving of the front part and the back part of the inflated element are approximately 30 -40 mm apart, so that the resultant cells are cylindrical when inflated. The total volume of gas within the inflated element may be between 7 and 9 litres, and the gas may be at a pressure of about 3 bar. While the inflated element is not provided with a vent to vent gas from within the element to the atmosphere, so that the inflated element, when inflated, remains inflated for a long period of time - to provide protection in the case of a protracted roll-over - there is venting between at least selected adjacent cells 8, to avoid any severe rebound. 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 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/sq m, such as 175 g/sq m may be used. It is to be noted that part of the inflated element extends rearwardly beyond the point 11, and is thus located between the head of the person 1 and the top of the B-post. Thus the risk of the head of the person impacting with the B-post is minimised. Since the upper edge of the inflatable element is secured to the upper part of the door frame along substantially the whole of its length, there is virtually no risk that the head of the occupant will pass between the upper edge of the inflatable element and the upper part of the door frame, with the head of the occupant of the vehicle thus inadvertently emerging from the body shell of the vehicle. Figures 2 and 3 illustrate another embodiment of the invention intended to provide protection not only for a person in the front seat of a motor vehicle such as a motor car, but also for a person in the rear seat of the vehicle. Referring to Figure 2, a recess 40 is provided in the door frame 41 of a motor vehicle, the recess extending over both the front door 42 and the rear door 43. The recess extends from a point 44 located near the lower end of the A-post to a point 45 located near the lower end of the C-post. A channel 46 is provided on the B-post, extending vertically. In the channel 46 is a ratchet, and received within the upper end of the channel 46 is a ratchet engaging slide member 47. The slide member 47 is connected to a tab 48 which forms part of an inflatable element 49, which is initially stored within the recess 40. The inflatable element 49 is shown in the inflated state in Figure 3. The inflatable element has its top edge 50 secured to the part of the door frame 41 that extends above the doors 42, 43 of the motor vehicle. The design of the inflatable element is similar to that shown in Figure 1, with the inflatable element presenting a plurality of parallel cells, which when inflated are substantially cylindrical. The structure of the inflatable element 49 may be the same as that described with reference to Figure 1. A gas generator 51 is provided which is connected to the inflatable element in such a way that when the gas generator is activated by a sensor that is formed integrally with the gas generator, or which is associated with the gas generator, and which responds to a side impact or to a roll-over situation to activate the gas generator, gas is initially supplied to the cells 52, 53, which are aligned with the tab 48. Thus initially, as the inflatable element 49 inflates, the cells 52 and 53 inflate and move the ratchet engaging slide member 47 downwardly. The ratchet engaging slide member 47 thus moves down the channel 46 to the position shown in Figure 3. The ratchet engaging slide member 47 engages the ratchet, and thus holds the tab 48 in its lower position. The rest of the cells 54 of the inflatable element are then inflated, and the inflatable element then extends fully across the upper parts of the windows in the doors 42, 43 of the motor vehicle. It can be seen that the lower edge of the inflated element 49 extends between the points 44 and 45 at the ends of the recess 40. As the inflatable element 49 inflates, so the length of the lower edge thereof decreases as a consequence of the inflation of the cells of the inflatable element. This reduction in the length of the lower edge, together with the action of the ratchet engaging slide member 47 ensures that the inflated element is retained in position as illustrated after it has been inflated. Figure 4 is a cross section showing the nature of the cells of the inflated element of Figure 1 and of Figures 2 and 3 showing that the regions of fabric between the cells that are woven together are relatively wide, the cells thus being separated by webs of fabric. The advantage of this is that a small volume of gas may be required to fully inflate the inflatable member, meaning that the inflatable element may be inflated rapidly. Figure 5 illustrates an alternative form of inflatable element comprising a plurality of cells 60. The upper edge of the inflatable element is of non-linear form and is connected to the non-linear portion of the door frame above the door. The configuration of the upper edge of the inflatable element and the configuration of the door Same correspond. It can be seen that each cell 60 is of substantially conical form, the cells being arranged adjacent each other and being parallel with each other. Between the cells are inverted triangular portions 61 where the fabric forming the cells is inter-woven. Whilst in the arrangement illustrated in Figure 5, the cells are shown immediately adjacent each other, in reality the cells are spaced apart It is possible to replace at least part of the inverted triangular region 61 with further conical cells of an inverted orientation.

Claims: A safety device in a motor vehicle, the device comprising a gas generator (5), 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 (8) connected to the gas generator to be inflated by gas from the gas generator, the inflatable element having an edge portion (7) secured to part of the door frame (4) of the vehicle, the said part of the door frame being non-linear, the inflatable element (8), when inflated, being positioned adjacent the door contained within the door frame, characterised in that the inflatable element is 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, selected parts of the first layer and the second layer being interwoven so that the front part and back part of the inflatable element are secured together, the inflatable element incorporating a plurality of substantially parallel elongated cells (8), the cells being spaced apart from each other by relatively wide regions of fabric between the cells that are inter-woven and being substantially vertical, the arrangement being such that as the inflatable element inflates the length of the lower edge of the inflatable element (8) is reduced and the lower edge of the inflatable element extends substantially tightly between two anchoring points (10,13) on the vehicle. A safety device according to Claim 1 wherein the inflatable element (49) is initially stored in a recess (40) provided in the door Same (41). A safety device according to Claim 1 or 2 wherein the cells (54) are substantially cylindrical when inflated. A safety device according to any one of the preceding claims wherein at least some of the cells (60) are of conical form when inflated. A safety device according to any one of the preceding Claims where there is internal venting between the cells (54). A safety device according to any one of the preceding claims wherein the inflatable element (49) is made of a fabric having a single layer weight of less than 300 g/m 2 . A safety device according to any one of the preceding Claims wherein when inflated, the pressure in the inflatable element (49) is approximately 3 bar. A safety device according to any one of the preceding Claims wherein the inflatable element (49), when inflated, extends past the B-post of the vehicle. A safety device according to any one of the preceding Claims wherein the inflatable element (49) incorporates a strap (9) to connect part of the inflatable element to the door frame (4). A safety device according to any one of the preceding Claims wherein the inflatable element is provided with a member (47) mounted on the inflatable element (49) adapted to move from an initial position to a further position on inflation of the inflatable element, a retaining arrangement (46) being provided on the body of the motor vehicle to retain the said member 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