GB2060357A - Passive three-point seat-belt system for a vehicle - Google Patents

Abstract

A passive three-point seat-belt system for a motor vehicle includes a tube set into the roof frame of the bodywork of the vehicle for guiding a runner 9 of a shoulder strap 7 whose forward or release position and rearward or restraining position are both shown. The runner 9 is carried by a flexible shaft driven by an electric motor 10 and wound onto and off a reel 13. The system further includes a tube set into the door of the vehicle for a runner 11 of a lap strap 8, also shown in its forward or release position and rearward or restraining position between which it is displaceable by way of a respective flexible shaft wound onto and off a respective reel 13 by a drive motor 12. The other, not illustrated, ends of the two straps 7 and 8 wind onto a double roller disposed at the middle of the vehicle. <IMAGE>

Description

SPECIFICATION Passive three-point seat-belt system for a vehicle This invention concerns a passive three-point seat belt system for a vehicle, of the kind having motordriven link points and providing a restraining position in which the belt engages with the body of the passenger and a release position in which the belt is lifted away from the passenger's body and comprising at least one runner which includes one link point of the seat belt and is disposed within a guide track.

Passive two-point or three-point seat belt systems which have hitherto been proposed do not permit location of the link points of the shoulder and lap strap in the region of the door post and of the common link point for the shoulder strap and the lap strap in the middle of the vehicle, as is known in the so-called active three-point systems. As is well known, the difference between an active and a pssive seat-belt system lies in the fact that active seat-belt systems presuppose the manual putting on of the seat belt by the wearer and are therefore often not used because of passenger comfort, whilst passive seat belt systems provide for automatic removal of the seat belt when the vehicle's door is opened and equally-automatic putting on or positioning of the same relative to the wearer when the door of the vehicle is closed.

If, as is the case with passive three-point systems which have previously proposed, the reaction forces which restrain the occupant of the vehicle in the event of a frontal impact of the vehicle are not transmitted fully to the vehicle's bodywork, but is partially transmitted to the vehicle seat, the danger exists that the seat, which customarily is adjustably-mounted, can be torn from its mounting so that the restraining effect of the seat belt is nullified.

The problem underlying the invention is to provide a passive seat belt system the link points of which lie entirely in the bodywork of the vehicle and are thus in a position to absorb even the most severe reaction forces such as may occur in the event of a frontal impact of the vehicle.

In accordance with the invention, this problem is solved in that the guide for runners including the link points for a shoulder strap and a lap strap is provided by commercially-available tubes, of which at least one lies in the door adjacent to the vehicle's occupant and, if necessary, another lies in the region of the roof frame of the vehicle's bodywork, whilst the belt exists for lap strap and the shoulder strap, disposed in the middle of the vehicle, is designed as a souble rooler.

The use of a commercially-available tube as the guide for the runners to which lap strap and shoulder strap are linked is not only particularly economical in so far as production is concerned, but it furthermore leads to constructional stiffening of the vehicle's door and also of the roof region of the bodywork in which in appropriate circumstances a tube for overall guidance may also be installed.

In addition, in further development of the invention it is possible to design the tube or tubes as an integrated unit with a lifting-piston cylinder unit which serves for driving the runners of the lap strap and the shoulder strap. In this way, besides the stiffening effect, additionally space saving and in particular optimum spatial arrangement of the link points of the shoulder strap and of the lap strap is achieved.

Either two electric motors are provided, one of which serves for displacing the runner of the lap strap between the restraining position and the release position and the other of which serves for displacing the runner of the shoulder strap between the release position and the restraining position, or else a single electric motor is provided for driving the two runners of the shoulder strap and the lap strap which motor can exert push and pull on the runners by way of a flexible shaft. For this, the driving motor is advantageously fitted with a transmission gearing. Furthermore a limit switch may be provided, which switch interrupts the motor circuit or circuits when the runner or respective runner runs into its end position and thus switches off the driving motor or motors.When the door of the vehicle is opened, the or each driving motor is switched on again to draw the runners into the release position.

Significant to the invention is the fact that thus seat belt comfort, often striven for in the automobile industry, is improved as a result of the provision of a double roller in the case of the three-point belt. With this arrangement of the system, belt deflection is eliminated. Such belt deflection (or turn back) has hitherto caused additional friction which in turn required higher spring forces, which results in increase, at times, of the belt pressure on the wearers body during journeys in the vehicle.

As a result of elimination of the belt deflection, the belt draw-out length from belt rollers, which are individual for each strap, becomes shorter. Thus, in turn, smaller rollers are needed and the belt roll-up spring can be designed so as to beweakerthan hitherto.

The double roller, onto which both the lap strap and the shoulder strap is wound, may conveniently be fastened to the usual gear tunnel of the vehicle using the frame of the vehicle seat; it can, however, alternatively be connected on one side to the usual seat rail block.

In the event of a frontal impact of a vehicle, inertia forces acting on the occupant's body are transmitted by way of the straps into the double roller and thus di rectly to the gear tunnel.

Extensive seat reinforcement, which in the past has always had to be effected when installing a passive belt system, becomes superfluous as a result of arrangement ofthe roller, in accordance with the invention, on the lower tube frame or seat rail.

The passive three-point belt system in accordance with the invention can, therefore, be incorporated subsequently into appropriate vehicles.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a fragmentary diagrammatic perspective view illustrating the bodywork, with the door removed, of a vehicle incorporating a seat belt sys tem according to the invention, the view being taken looking into the interior of the passenger compart ment of the vehicle; Fig. la is an enlarged detail of part ofthe system of Fig. 1; Fig. 2 is a view comparable with Fig. 1 but showing a vehicle with its door, and the corresponding parts of the seat belt system, in place; Fig. 3 is a view similar to Fig. 2 but showing another modification of the electric-motor drive of the seat belt system; Fig. 3a is a part-sectional enlarged detail of part of the system of Fig. 3;; Fig. 4 is a schematic perspective view illustrating the gear tunnel of a vehicle with the double roller of the seat belt system in accordance with the invention mounted thereon; Fig. 5 is a view similar to Fig. 1 but showing yet a further modification; Fig. 6 is a view comparable with and showing the same system as in Fig. 5, this figure illustrating the strap ends, which are fastened to runners and are guided in a tube system, the drive being effected hydraulically by way of a piston-cylinder unit; Fig. 6a is an enlarged detail of part ofthe system of Fig. 6 shown partly in section; Fig. 7 is a view similar to Fig. 6 but illustrating yet another embodiment of the system of the invention; and Fig. 8 shows schematically the cross-sections of two vehicle doors incorporating respectively two tubes and one tube for a piston-cylinder underpressure drive for alternative seat belt systems according to the invention.

In the passive three-point seat belt system illustrated in Fig. 1 ofthe drawings, a shoulder strap 1 is guided by a runner 2, which for its part slides in a guide provided by a commercially-available tube 3 set into the roof region of the vehicle's bodywork, and under the control of an electric motor 4, serves to shift the shoulder strap 1 between a restraining position lying across the vehicle occupant's body and a forward release position indicated at I. Drive of or displacement of the runner 2 is effected by way of a flexible shaft 5 which is would into a spring-loaded winding drum 6.

Details of how the runner 2 is displaced by the flexible shaft 5 which in turn is shifted by the electric motor 4 can be appreciated from Fig. la. The flexible shaft 5 comprises a wire core around which are disposed a plurality of discs which combine to form a rack into which a worm wheel 4a engages. Depending on the direction of rotation of the electric motor 4, the runner 2 of the shoulder strap 1 is drawn, by way of the flexible shaft 5, between its restraining position shown to the left hand side in Fig. 1, and its releasing position shown towards the front of the vehicle at I in Fig. 1.

In Fig. 2, the ends of the shoulder strap, which is now indicated by the reference numeral 7, and of the lap strap which is now indicated by the reference numeral 8, are shown cut away to illustrate the various operating positions. Serving to adjust runner 9 of the shoulder strap 7 is an electric-motor drive 10, and serving to adjust runner 11 of the lap strap 8 is an electric-motor drive 12. The flexible shaft for displacing the runners 9 and 11 is stored on the two flat or shallow shaft winding drums 13.

As an alternative, one can make do with a single electric-motor drive 14 for both the lap strap and the shoulder strap, as shown by the exemplified embodiment in accordance with Fig. 3. According to this, a guide tube 15 for shoulder strap 22 is arranged in the upper region of vehicle door 16 and a guide tube 17 for lap strap 18 is arranged in the lower region of the vehicle door 16. The straps are connected to their respective shafts by respective runners, of which one only is indicated at 19, these shafts extending to winding drum 21.

The drive of the lap strap 18 and shoulder strap 22 in the arrangement of Fig. 3 is illustrated in more detail in Fig. 3a. As can be seen, driving motor 23 has an axle extending to both sides thereof and on these are respective worm wheels 23a and 23b which engage with respective flexible shafts 15a,17a, the form and operation of which corresponds to the shaft 5 above described with reference to Fig. 1.

These flexible shafts 1 Sa, 1 7a are connected to the respective runners and thus serve for displacing the respective strap ends.

In its release position, the runner of the shoulder strap 22 is located in the position S1 in Fig. 3 and upon actuation of the electric-motor drive 22, it is displaced into the restraining position S2, in which the shoulder strap 22 restrains the vehicle occupant.

Correspondingly, the runner 20 of the lap strap 18 slides from the release position B1 into the restraining position B2.

Fig. 4 shows diagrammatically the arrangement of the double roller, not shown in its details, on the upper side of the vehicle's usual gear tunnel 24. The shoulder strap (not shown) emerges from upper slot 25 of double-roller cover 26, and the lap strap (not shown) emerges from the lower slot 27 ofthe double-roller cover 26. Fastening of the double roller arrangement is effected by way of seat rail 28 with holder and seat tube frame 29.

In the arrangement of Fig. 6, shoulder strap 30 is in the release position (when its link point is in position S1,and is shifted, upon actuation by a postoncylinder system 31, which advantageously operates by suction, when its link point is moved into restraining position S2. The runner of the shoulder strap 30 lies in the guide tube 32. Lap strap 33 is disposed in its release position when its link point is in the position B1 and it similarly moves, as does the shoulder strap 30, after the closing of the door 34, into the restraining position when its link point and runner move to the position B2.

In this embodiment as has been mentioned, drive is achieved by suction or underpressure. As a result of door 34 being closed, a three or two-way valve Inot shown) is actuated. As a result of the plunging of the piston of the piston/cylinder system 31 inwards of its housing, venting holes are closed and the suction path from the motor (not shown) to the working cylinder is freed. The housing, closed on the suction side of the cylinder, has only one air inlet and outlet through an inserted pipe socket. Connection of the contact points in the system is established by suction hoses or tubes.

The suction, arising from the motor, in the system draws the piston in the cylinder away from a rest position until it encounters a stop or abutment. This stop or abutment is formed by the runner of the respective strap when it moves into its position corresponding to the respective strap being in the restraining position. Suction is constantly available during a journey in the vehicle.

A non-return valve incorporated in the system ensures the maintenance of the level in the cylinder in the event of a drop in the vacuum performance of the motor.

The draw cable fastened to the piston 31a of the piston-cylinder system 31 draws the shoulder strap 30 or lap strap 33 respectively, by way of the respective runner which moves between the release position S1 or B, respectively and the restraining position S2 or B2 respectively.

The draw cable fastened to the runner draws out restoring spring 35 into a working condition in which its stored energy is available on call.

The operating principle ofthis drive is illustrated diagrammatically in Fig. sue with reference to a much simplified schematic representation. According to this, the restoring spring 35, exerts itself to draw the runner 32 out of the restraining position, into which it has been drawn by the piston 31a by the vacuum prevailing in the cylinder 31b when this vacuum has been cancelled by venting the cylinder 31b, and to shift it into the rest position S 1. When the vacuum is re-established by the running motor of the vehicle (not shown) displacement of the runner 32 is effected in the reverse direction, until this has returned into the restraining position S 2.

The runners with the draw cables run in a guide tube. Deflection of the draw cables into the varied draw directions is made possible by incorporated guide rollers (not shown) which, for varying the force and path, may be geared cable pulleys.

When door 34 is opened, an incorporated valve spring forces the piston of the piston-cylinder system 31 into the initial position. The valve and the cylinder are ventilated, the tensioned restoring spring 35 draws the straps 30 and 33 into the release positions S1 and B1 respectively.

Fig. 6 shows the installed position of the working cylinder, which is of fairly large diameter, which serves as the drive for the lap strap 33 and the shoulder strap 30, inside the vehicle door 34.

Fig. 7 shows an arrangement comprising two working cylinders 36 and 37 of smaller diameter, also installed in the vehicle door, the drive being effected separately for the lap strap and the shoulder strap (which are only partly shown in this figure).

Fig. 5 shows an exit point of the lap strap 33 and the shoulder strap 30 positioned at the rear seat edge, i.e. at the transition from the back to the seat surface.

Fig. 8 shows, schematically, the approximate positions of the tubes or pipes which from the respective working cylinders (e.g. of Figs. 7 and 6). For accommodating the larger tube 38 a change in the inner door profile may be necessary.

If, on the other hand, two smaller tubes 36 and 37 (see also Fig. 7) are used, then such a change in the inner profile of the vehicle door is not necessary.

Difficulties in accommodating the working cylinders for the vacuum drive may arise where a window raiser is incorporated into the door. In that event it would be expedient to modify somewhat the installation of the window raiser, in order to provide space for the working cylinders provided in the arrangement in accordance with the invention.

Claims (6)

1. A passive three-point seat belt system for a vehicle, such as a motor car, of the kind having motor-driven link points and providing a restraining position in which the belt engages against the body of the occupant and a release position in which the belt is lifted away from the occupant's body and comprising at least one runner which includes a link point of the seat belt and is disposed in a guide track, characterised in that the guide for runners including the link points for a shoulder strap and a lap strap is provided by commercially-available tube of which at least one lies in the door adjoining the vehicle's occupant and, if necessary, another lies in the region of the roof frame of the vehicle's bodywork, whilst the belt exits for the lap strap and the shoulder strap, disposed in the middle of the vehicle, is designed as a double roller.

2. A three-point seat belt system as claimed in claim 1, characterised in that the drive of the runners of the lap strap and the shoulder strap is provided by a lifting-piston cylinder unit which is integrated into the guide of the runner.

3. A three-point seat-belt system as claimed in claim 1, characterised in that the drive of the runners of lap strap and the shoulder strap is provided by two electric motors, one of which serves for displacing the runner of the lap strap between its restraining and release positions and the other of which serves for displacing the runner of the shoulder strap between its release and restraining positions.

4. A three-point seat belt system as claimed in claim 1, characterised in that a single electric motor is provided for driving the runners of the shoulder strap and the lap strap, the runners being pushed or drawn by means of a flexible shaft.

5. Athree-point seat belt system as claimed in claim 1, characterised in that the runners of the lap strap and the shoulder strap are located in a slotted guide tube and are adapted each to be pushed or drawn by way of a flexible shaft and an intermediate gear, by means of an electric motor.

6. Athree-point seat belt system for a vehicle substantially as hereinbefore described with reference to and as illustrated in Figs. 1 and la; in Fig. 2, in Figs. Band 3a, in Fig. 4, in Fig. 5, in Figs. 6 and 6a, in Fig. 7, or in Fig. 8 of the accompanying drawings.