WO2002022406A1

WO2002022406A1 - Safety belt system

Info

Publication number: WO2002022406A1
Application number: PCT/SE2001/001914
Authority: WO
Inventors: Lars Sundholm; Mats Lindquist
Original assignee: Andum Ab
Priority date: 2000-09-12
Filing date: 2001-09-07
Publication date: 2002-03-21
Also published as: AU2001284602A1; SE0003225D0

Abstract

The present invention concerns a safety belt system (2) for a motor vehicle, comprising at least one safety belt strap (8, 10) arranged on a vehicle seat and a belt buckle (12, 100) arranged to the safety belt strap, which comprises at least one lap belt strap (24, 26) and one or more shoulder straps (28, 30). The lap belt strap is partable and can suitably comprise at least two from each other separable belt straps (32-38). The present invention concerns also a belt buckle, a belt reel, a method and a usage.

Description

SAFETY BELT SYSTEM

Technical Area The present invention concerns a safety belt system. The present invention also refers to a belt buckle, a belt reel, a method for a safety b lt system and a usage of separable belt straps in a safety belt system.

Background Safety demands on motor vehicles especially are getting increasingly higher. High demands are today being put on the design of vehicle seats to withstand severe collisions. Safety demands are also expected to increase in the future, which has already led to improved belt systems. One improvement that has taken place is an integration of all seat belt anchor points into the vehicle seat, a concept called "belt-in-seat". Passenger cars usually have a three-point safety belt where two anchor points are arranged on the floor of the vehicle and one anchor point is arranged on the passenger car's so-called B-pillar. The new concept, with belt anchor points integrated in the seat, has eventually begun to attract much attention due to its improved safety performance in comparison with a conventional belt system.

A person involved in a head-on collision with their vehicle is regarded as being a person moving at a certain speed in a space and this speed must be retarded to zero. This is achieved via force of contact applied to some part of the torso. The amplitude of this force depends partly on the initial speed and partly on the characteristics of the part making contact with the torso. Of course, this is the case if the part is completely stationary when the torso makes contact with it. In a motor vehicle, it is the interior equipment and the seat belt that applies this force to the torso and, normally, the vehicle will not have become completely stationary when the torso makes impact. In other words, the reference points of the force are also in retardation. The retardation of the vehicle occurs through the deformation of its front structure and then takes place at a relatively uniform rate. The person occupying the car, on the other hand, will not immediately put a strain on the protection system but will continue to move freely forward in the vehicle for a certain distance. The distance of deformation in the protection system is naturally much shorter than in the front structure, which is why the retardation of the occupant is around twice that of the vehicle. The most optimum situation is when a person is integrated with the vehicle, i.e. sitting fixed to the body. In that case, the person will experience the same retardation as the vehicle. The kinetic energy of the occupant will mainly be absorbed by the deformation of the front structure with some possible minor deformation of the occupant's fixing points in the car. In the latter case, the retardation of the occupant will therefore be reduced by half and consequently so will the forces of contact on the torso.

Three-point safety belts are usually used in passenger cars, where two anchor points are arranged on the floor of the vehicle and one anchor point is arranged on the passenger car's so-called B-pillar. The belt comprises a continuous strap, where, after fastening a person in the vehicle seat, the lower part of the belt, also called the lap strap, is arranged over/below the hips. The upper part of the belt, also called the shoulder strap, stretches diagonally over the torso from the hip diagonally up over the abdomen and the lower chest, and over the shoulder. Four-point belts, on the other hand, are normally being used in motor sports at present due to the high risk of injury and the increasingly higher safety demands. These belts are usually secured with a belt buckle on the upper torso.

The discussion made above can be summarised in that there are two main methods of reducing the forces of contact on the torso of an occupant of a vehicle in a collision. Naturally, this will also reduce the risk of injury when the forces of contact are reduced. The first method entails the design of an interior equipment system that will absorb any energy that is exerted on it. This can be energy limiting devices in the seat belts or deformable steering columns. The second method entails the occupant's torso being fixed to the vehicle as rapidly as possible so that the deformation of the front structure can be utilised to absorb kinetic energy. This can be a belt tensioner and, to a certain extent, airbags. This second method is also called the "ride-down" affect. Of these two methods, it is undoubtedly the latter that is most effective with regard to limiting the magnitude of the forces of contact and consequently the risk of personal injury. This is due to the limited deformation zone available for the protection system inside the vehicle. The problems described above can be considerably reduced or eliminated completely, increasing the so-called "ride-down" affect, if the occupant involved in a collision is rapidly fixed to the vehicle by tensioning the belt and moving the upper body strap (also called the shoulder strap) to a more suitable position on the upper part of the torso for securing it rapidly to the seat under maximum energy absorption. It is certainly already known for a safety belt system to move the upper body strap higher on the torso in case of a collision but known designs have so far exhibited a number of disadvantages. Known designs do not operate optimally, are uncomfortable, technically complicated and cumbersome.

Already known through US-A-5, 135,257 is a safety belt strap for vehicle seats that is intended to gather up the diagonal strap (also known as shoulder strap) so that it is not located in an uncomfortable position on the neck or face of the passenger when in motion but is located farther down on the torso. In case of a collision, the strap is so arranged that it comes loose from the safety belt so that the diagonal belt can move to a more suitable position from the point of view of crash safety, located higher on the upper torso.

Account of The Invention The present invention intends to accomplish a safety belt for motor vehicles where a shoulder strap in the belt system in case of a collision moves to a position on the passenger's/driver's upper torso that is better at absorbing energy than its initial position (at normal loads). The object of the invention is to better manage the load on the torso caused by a collision. The present invention also intends to achieve a faster and more efficient solution than conventional designs and eliminate other disadvantages of present technology as described above.

This solution is achieved with a safety belt system possessing the characteristics specified in Claim 1. More exactly, Claim 1 according to the present invention concerns a safety belt system for a motor vehicle comprising at least one safety belt strap arranged on a vehicle seat and one belt buckle arranged on the safety belt strap. The safety belt strap comprises at least one lap belt strap and one or more shoulder straps, in which the lap belt strap is partable. The lap belt strap comprises at least two belt straps that can be separated from each other.

One advantage of a safety belt system according to the present invention is that as the lap belt strap will separate in case of a collision, the shoulder strap/straps will be located more centrally on the upper torso in case of a collision, whereby the ability of the safety belt system to absorb strain is improved. The passenger's/driver's torso is more rapidly fixed to the vehicle seat, whereby the deformation of the front structure of the vehicle is more efficiently utilised for absorbing kinetic energy.

According to a preferred embodiment of the present invention, the safety belt system comprises a four-point belt including two separate straps arranged on each side of the driver's seat intended to be coupled with a belt buckle when anchoring a person in the vehicle seat, where the upper free end of each strap has respective anchor points on the upper part of the seat backrest and where the lower free ends of the straps are arranged on anchor points in the lower part of the seat backrest/vehicle seat. An advantage of a four-point belt is that the belt mountings are located closer to the torso of a person occupying the vehicle seat, which provides a better fit of the belt to the body irrespective of the size of the occupant. According to an additional preferred embodiment of the present invention, the safety belt system comprises a partable belt buckle. An advantage of a belt buckle containing devices that are separable relative to each other is such that an upper part of the buckle is released from a lower part of the buckle. The upper and lower parts can be separated, whereby the upper part can be moved and located more centrally with the shoulder strap on the upper torso of a passenger/driver involved in a collision.

According to an additional preferred embodiment, the present invention comprises a belt tensioner including two halves, one upper and one lower belt reel arranged adjoining each other. In case of a collision, the two halves are arranged to move independently, whereby the lower half tensions the lower safety belt lap strap and the upper half of the reel locks to fix the upper lap belt strap.

The present invention includes also a belt buckle for a motor vehicle safety belt system, where the safety belt system comprises at least one safety belt strap arranged on a vehicle seat and one belt buckle arranged on the safety belt strap, the safety belt strap includes at least one lap belt strap and one or more shoulder straps, that the lap belt strap comprises at least two belt straps that are separable from each other and that the belt buckle comprises at least two locking devices that are arranged to separate in case of a collision.

The present invention includes also a belt reel for a motor vehicle safety belt system, where the safety belt system comprises at least one safety belt strap arranged on a vehicle seat and one belt buckle arranged on the safety belt strap, the safety belt strap includes at least one lap belt strap and one or more shoulder straps, that the lap belt strap comprises at least two belt straps that are separable from each other and that a belt tensioner comprising an upper and lower belt reel is arranged on the safety belt strap.

The present invention includes also a method for a motor vehicle safety belt system comprising at least one safety belt strap arranged on a vehicle seat and one belt buckle arranged on the safety belt strap, the safety belt strap includes at least one lap belt strap and one or more shoulder straps, that as a lap belt strap is arranged at least two belt straps that are separable from each other, whereby the separable belt straps are arranged to separate in case of a collision. The present invention comprises also the use of separable belt straps in accordance with the safety belt system or method. Figure Description The invention will now be described in detail in the form of non-limiting embodiments illustrated with the help of the enclosed figures, where

fig. 1 A is a front view illustrating a safety belt system arranged on a motor vehicle seat.

fig. IB is a front view illustrating a safety belt system arranged on a motor vehicle seat according to fig. 1A, as the belt is arranged in case of a collision.

fig. 2 is a front view illustrating a partable belt buckle according to one embodiment.

fig. 3A is a front view illustrating a safety belt system arranged on a motor vehicle seat as the belt is located in case of a collision.

fig. 3B is an enlargement illustrating the perspective view of a belt reel according to fig. 3 A.

fig. 4A-C illustrates the perspective view of an embodiment of a belt buckle.

Description of an Embodiment Fig. 1 A illustrates a safety belt system 2 according to the present invention arranged on a motor vehicle seat 4, comprising a four-point belt 6, including two separable straps, the first strap 8 and the second strap 10, arranged on respective sides of the vehicle seat, intended to be coupled together with a belt buckle 12 to anchor an occupant to the vehicle seat. At the upper free ends of each strap 8, 10 are respective anchor points 14, 16, that can be made up of belt tensioners, on the upper part of the vehicle seat 4 backrest 18 and where the lower free ends of the straps 8, 10 are arranged on anchor points 20, 22, which can be made up of belt tensioners/belt reels, on the lower part of the backrest/vehicle seat. Fig. 1 A illustrates the straps in the safety belt system as they are arranged in position

A with a person occupying the vehicle seat with the safety belt on and in normal use with low or moderate strain while the person is travelling in the vehicle. As illustrated in fig. 1-2, the respective straps 8, 10 have a lap belt section 24, 26 and respective shoulder straps 28, 30. Between the lap belt section 24, 26 and the shoulder straps 28, 30 is arranged the belt buckle 12. The respective lap belt section 24, 26 each comprise two belt straps 32-38. More exactly, the lap belt strap section 24 comprises an upper right belt strap 32 and a lower right belt strap 34. The lap belt strap section 26 comprises an upper left belt strap 36 and a lower left belt strap 38. The belt buckle 12 is partable and comprises an upper right locking device 40, a lower right locking device 42, an upper left locking device 44 and a lower left locking device 46. The upper right belt strap 32 of the lap belt strap section 24 is joined to the belt buckle 12 upper right locking device 40. Correspondingly, the lower right locking device 42 is joined to the lower right belt strap 34, the upper left locking device 44 is joined to the upper left belt strap 36 and the lower left locking device 46 is joined to the lower left belt strap 38. Accordingly, belt straps 32-38 are arranged partially in parallel along the length of the belt strap and in contact with each other along one edge 39 of the respective belt strap.

Fig. IB illustrates the safety belt system in a position B as the belts 28-38 and the locking devices 40-46 are moved and arranged in case of a collision. In case of a collision, the lap belt straps 24, 26 separate into two parts. The upper right belt strap 32 from the lower belt strap 34 and upper left belt strap 36 from the lower belt strap 38. The belt buckle also separates into two parts at the same time, one upper locking element 48 and one lower locking element 50. The lap straps 24, 26 comprise a means of acting on the belt straps to move them in opposite directions in case of a collision. In position A in fig. 1 A, the partable belt straps 32-38 are fixed together with one or more means of fixing such as a wire, Velcro or stitching along a parting line 52, 54. In position A, the right locking devices 40, 42 are also joined side by side to a first part 56 with a means of jointing such as a wire, Velcro or stitching. The left locking devices 44, 46 are correspondingly joined side by side to a second part 58. The right locking devices 40, 42 are arranged fixed to the left locking devices 44, 46 in a suitable technical manner when locking the belt buckle 12. Suitably, the right locking devices 40, 42 include locking tongues 60, 62 protruding from the locking devices and adapted for engaging and locking in the left locking devices 44, 46, i.e. in a first slot 61 and second slot 63 in the belt buckle housings 44, 46. The locking tongues 60, 62 can suitably be in two sizes so that they fit the locking devices 44, 46 in one definite position.

The following takes place in case of a collision, based on the original position A in fig. 1A:

A predetermined default value for the load on a vehicle is exceeded, whereby a sensor or similar device is arranged to act on the means of fixing, which in turn act on the lap belt sections 24, 26 to separate them along the parting line 52, 54. At the same time, the right locking devices 40, 42 and the left locking devices 44, 46 are also arranged to act on the means of fixing, which in turn affect the separation of the locking devices along the first and second parts 56, 58. The release mechanism for the sensor can be designed in a technically well-known and suitable manner and can, for instance, comprise a pyrotechnic charge being triggered in case of a collision (cp. e.g. triggering mechanisms for airbags). As stated above, the separation can be achieved with a connecting means of fixing such as a wire is arranged along parting lines 52, 54 and along the first and seconds parts 56, 58 of the locking device. Suitably, the wire can be pulled out by the belt tensioners 64, 66, whereby the lap belt and belt buckle will separate. The upper belt straps 32, 36 and the upper locking element 48 withdraw from the lower belt straps 34, 36 and the lower locking element 50 to position B as exhibited in fig. IB by the shoulder straps 28, 30 being tensioned by the belt tensioners arranged at anchor points 14, 16, whereby the upper locking element 48 is located centrally at chest height. Suitably, the belt tensioners 64, 66 can also be arranged at anchor points 20, 22 to simultaneously stretch the lower belt straps 34, 38. An advantage of the four-point belt described above is that the belt mountings are located closer to the torso of a person occupying the vehicle seat, which provides a better fit of the belt to the body irrespective of the size of the occupant.

Fig. 3A illustrates a safety belt system arranged on a motor vehicle seat in the position such as when the belt is located after a collision has taken place (principally as exhibited by position B in fig. IB). The belt tensioners 64, 66 can be arranged to tension the lower belt straps 34, 38 at the same time as the separation of the lap belt takes place. Fig. 3B is an enlargement illustrating a belt tensioner 66 according to fig. 3A containing a belt reel 68, which is divided into two halves, one upper reel 70 and one lower reel 72. In normal conditions, i.e. when a collision has not taken place, the upper and lower reels will interact so that the continuous lap belt 26 (see fig. 1A and 2) comprising the left belt straps 36, 38 or the lap belt 26 with the right belt straps 32, 34 can run on and off the belt reel 68. The reels 70, 72 interact and thereby rotate synchronously in the same direction when a strap is being run on or off the reel. In case of a collision, the two reel halves 70, 72 are arranged to operate independently as two individual reels (for which a technically acceptable solution can be found) but still be arranged adjoining each other, whereby the lower reel 72 is arranged to tension the belt strap 38, while the upper reel 70 is arranged to lock the belt strap 36 so that it is fixed. The trigger mechanism for the belt reel in case of a collision can be designed in a technically well-known and acceptable manner and can comprise a pyrotechnical charge to enable the reel halves 70, 72 to act independently so that one of the reels locks and the other tensions the strap. Fig. 4A-C illustrates one embodiment of a partable belt buckle 100, comprising separable locking devices 102-108. The belt buckle comprises an upper right locking device 102, a lower right locking device 104, an upper left locking device 106 and a lower left locking device 108. The locking devices 102-108 are disc-shaped and relatively thin in relation to their length/breadth. In normal cases, i.e. in normal usage of the belt (i.e. when not in a collision), the locking devices 102, 104 are arranged joined to each other and constitute a right lock section 110. Correspondingly, the left locking device 106, 108 are arranged joined to each other and constitute a left lock section 112. To the right lock section 110 is arranged a right lap belt section 114 and to the left lock section 112 is arranged a left lap belt section 116. The upper locking devices 102, 106 comprises an upper locking element 103, which is arranged with a certain offset to the respective lower locking devices 104, 108, which comprises a lower locking element 105. When a person occupying a vehicle seat is to be fastened to the seat with a safety belt system, the two lock sections 110, 112 with respective lap belt sections are locked together from the position illustrated in fig. 4A to the locked position illustrated in fig. 4B (the locking mechanism can be designed in a technically acceptable manner).

The following takes place in case of a collision, based on the original position in fig. 4B: A predetermined default value for the load on a vehicle is exceeded, whereby a sensor or similar device is arranged to act on the lap belt sections 114, 116 to separate them along the parting line 118, 120. Meanwhile, the upper locking element 103 is arranged to affect a separation relative to the lower locking element 105. The result is illustrated in fig. 4C, where the arrows indicate the displacement and withdrawal of the upper locking element 103 from the lower locking element 105. The lower, rear, disc-shaped locking element 105 (locking devices 104, 108) acts as a sliding surface for the upper locking element 103 (locking devices 102, 106) during withdrawal.

Claims

1. Safety belt system (2) for a motor vehicle comprising at least one safety belt strap (8, 10) arranged on a vehicle seat and a belt buckle (12; 100) arranged on the safety belt strap with the safety belt strap comprising at least one lap belt strap (24, 26) and one or more shoulder straps (28, 30), characterised in that the lap belt strap is partable, whereby the partable lap belt strap comprises at least two belt straps (32-38) that are separable from each other.

2. Safety belt system according to Claim 1, characterised in that the lap belt strap comprises at least one upper belt strap (32, 36) and one lower belt strap (34, 48), the belt straps being arranged partially parallel along the length of the belt strap and in contact with each other along the edges (39) of the length of the respective belt strap, whereby the belt comprises one or more means of fixing that in case of a collision are arranged to affect a movement of the belt straps away from each other.

3. Safety belt system according to Claim 1, characterised in that the belt buckle includes at least two separable locking devices (48, 50; 102-108), which are arranged to part in case of a collision.

4. Safety belt system in accordance with Claim 3, characterised in that the locking devices (102-108) are disc-shaped.

5. Safety belt system according to Claim 3, characterised in that the belt buckle comprises a first locking tongue (60) and a second locking tongue (62), which, when locked, are arranged in a first slot (61) and a second slot (63) in the belt buckle housing (44, 46), whereby the belt buckle comprises ah upper locking element (48; 103) and a lower locking element (50; 105), which, in case of a collision, move away from each other.

6. Safety belt system according to any one of the previous claims, characterise d in that a belt tensioner (64, 66) is arranged to the safety belt strap comprising an upper (70) and a lower (72) belt reel.

7. Belt buckle (12; 100) for a safety belt system for motor vehicles, wherein the safety belt system comprises at least one safety belt strap (8, 10) arranged on a vehicle seat, whereby the belt buckle is arranged to the safety belt strap, and that the safety belt strap comprises at least one lap belt strap (24, 26) and one or more shoulder straps (28, 30), c h a r a cterisedin that the lap belt strap is partable and comprises at least two from each other separable belt straps (32-38), whereby the belt buckle comprises at least two separable locking devices (48, 50; 102-108), which can be parted from each other.

8. Belt reel for a safety belt system (2) for motor vehicles, wherein the safety belt system comprises at least one safety belt strap (8, 10) arranged on a vehicle seat and a belt buckle (12; 100) is arranged to the safety belt strap, which comprises at least one lap belt strap (24, 26) and one or more shoulder straps (28, 30), c h a r a c t e r i s e d in that the lap belt strap is partable and comprises at least two from each other separable belt straps (32-38), whereby a belt tensioner (64, 66) is arranged to the safety belt strap, the belt tensioner comprising an upper (70) and lower (72) belt reel.

9. Method for a safety belt system (2) for a motor vehicle comprising at least one safety belt strap (8, 10) arranged on a vehicle seat and a belt buckle (12; 100) arranged on the safety belt strap with the safety belt strap comprising at least one lap belt strap (24, 26) and one or more shoulder straps, c h a r a c t e r i s e d in that as a lap belt strap is arranged at least two belt straps (32-38) that are separable from each other, whereby the separable belt straps are affected to part in case of a collision.

10. The use of separable belt straps (32-38) according to Claims 1-6 or 9 in a safety belt system (2).