A SAFETY MEANS FOR VEHICLE SEATS

Abstract: The invention concerns a safety device for vehicle seat in order to lessen the load on the means interconnecting the seat cushion (2) of the vehicle seat and the seat back (3) under conditions of heavy deceleration, and particularly in vehicle seats having an upper part (6) of the safety belt (5) secured at the upper part of the seat back. In accordance with the inventon the safety device consists of an interconnection wire extending between the top of the seat back and the neighbouring side of the vehicle chassis and in such a way that it is yieldable during adjustment of the vehicle seat but locks in position in deceleration situations.

Description: A SAFETY MEANS FOR VEHICLE SEATS Vehicle seats, particularly vehicle seats of the kind to the upper end of which is attached one end of the belt part associated with the seat, are exposed to very heavy stress in the part of the seat interconnecting the back of the seat with the cushion thereof, in the event of abnorm- al deceleration, such as sudden braking or collisions. Under these conditions, there is a risk that the back of the seat will fold forwards and consequently the belt will fail to give the person occupying the seat the intended protection. In any event, the point of interconnection, which nowadays often is in the form of an angularly adjustable articulated joint, must be of considerable dimensions. The main purpose of the invention is to eliminate this drawback by lessening the load on the interconnec- tion joint between the seat cushion and the seat back. This purpose is achieved in a safety device in accordance with the invention which is essentially characterized in that it consists of an interconnection wire extending between the top of the seat back and the neighbouring side of the vehicle chassis and in such a way that it is yieldable during adjustment of the vehicle seat but locks in position in deceleration situations. Owing to this device the forces to which the upper attachment point of the belt is exposed when load is exerted on the belt, are transferred directly to the vehicle chassis via the seat back, with the result that the load exerted on the back will only be minimal. Con¬ sequently, the joint may be manufactured with moderate dimensions. The invention will be described in closer detail in the following with reference to the accompanying drawings, wherein: Fig. 1 is a perspective view of a part of the vehicle as seen through the left front door of the vehicle and illustrating one embodiment of the inventive object; Fig. 2 is a sectional view of the device indicated in Fig. 1 in release position; Fig. 3 illustrates the same part but in the latched position; Fig. 4 is section taken along line IV-IV in Fig. 3; Fig. 5 is a perspective view as seen from behind, of the top of the vehicle seat fitted with a strap storage device in accordance with an alternative embodiment, and Fig. 6 is a view corresponding to Fig. 1 but showing a safety means in accordance with the invention adapted to fit a two-door car. In Fig. 1, the seat of a vehicle is designated generally by numeral reference 1. Reference 2 designates the cushion part of the seat and reference 3 the back thereof. Reference numeral 4 designates a means for adjustment of the position of inclination of the back. The safety belt associated with the seat is designated by 5. The diagonal part of the belt is secured to the upper end of the seat back and extends diagonally there¬ from downwards to a coupling means 7, while the hip part 8 of the belt 5 extends across the seat to an attachment bracket 9 supported by the seat portion proper of the chair. Numeral reference 10 designates a wire which in accordance with the embodiment illustrated is in the form of a strap. A bracket 11 secures the strap 10 to the top of the seat back 3 and by means of a delinking element 12 mounted on the rear door of the vehicle the strap projects down into a hollow profile member 13 which serves to guide a runner means 14, see Figs. 2-4, and in which the lower end of the strap 10 is attached. The guide 13 is in the form of an essentially ver- tical hollow profile member having a C-shaped configu¬ ration, as most clearly apparent from Figs. 2-4. Within the scope of protection of the invention, the hollow profile member could, of course, be shaped as an entirely closed tube. Alternatively, the guide could have a con¬ figuration differing from that of a hollow profile member For instance, the runner may be arranged for guidance on the exterior of the profile member. A pawl 15, pivotally mounted on the runner for pivotal movement about a pin 16, is provided with a weight 17 which is positioned in such a manner that the center of gravity T of the body formed jointly by the pawl 15 and the weight 17 will be posi- tioned at a distance A behind the axis 16, calculated in the travelling direction V of the vehicle, while at the same time the centre of gravity T will also be positioned at a distance H below the pivot axis. Numeral reference 18 designates the nose of the pawl, said nose engaging, in the position illustrated in Fig. 3, with one of a number of locking teeth 19 extending vertically along the guide. By numeral reference 20 is designated a tension spring which tends to pivot the pawl upwards to the neutral pawl position illustrated in Fig. 2, i.e. the position in which its nose 18 is not in engagement with anyone of the teeth 19. When the vehicle, normally travelling in direction V, is exposed to an abnormal decelerating force, for instance as a consequence of sudden braking or a collision, the pawl is pivoted in the clockwise direction as seen in Figs. 2 and 3, into engagement with one of the locking teeth 19, thus pre¬ venting the strap 10 from being pulled out and in con¬ sequence thereof the seat back from being folded forwards. Any sudden pull on the strap for whatever reason also brings the pawl to assume its position of engagement illustrated in Fig. 3, preventing further pulling out of the strap. Preferably, means are provided to shift the latching body 15 to its release position by manipulations from outside the vehicle, should the latter assume a very oblique position or in case the pawl becomes stuck as a result of an accident. The door lock could also be connected to the pawl in order to release the latter when desired. In accordance with the alternative embodiment illus¬ trated in Fig. 5, the components corresponding to those of the embodiment just described are referred to by identical numeral references. Thus, the back of the seat is re¬ ferred to by numeral 3 and the strap extending between the seat back and the vehicle side is designated by reference 10. However, in accordance with this embodiment a reel-up mechanism 21 of a type similar to that of a conventional safety-belt reel mechanism is arranged on the seat back. A reel-up mechanism of this kind is indicated in Fig. 5 and is designated on this drawing figure by numeral 22. The reel-up mechanism is provided in a manner known per se with locking means preventing unwinding of the strap 6 in the event of abnormal vehicle deceleration. Also the reel- up mechanism 21 preferably is provided with means of this kind. In accordance with this embodiment, the strap need only be attached to the vehicle side by means of a suit- able connecting member. When the vehicle is not exposed to abnormal dece¬ leration forces the strap 10 preferably is free to move inwards and outwards, thus being yieldable in such a manner as to allow adjustment of the vehicle seat posi- tions, both with respect to the longitudinal position of displacement of the latter as with respect to the posi¬ tion of inclination of the seat back. The embodiments described in the aforegoing are best suited to vehicles having separate back-seat access doors, since the strap 10, which extends permanently between the vehicle side and the seat back, would constitute a hin¬ drance for passage between the seat back and the door frame. However, Fig. 6 illustrates an embodiment which is suitable for use in vehicles without separate rear side doors. Also in this drawing figure components correspond¬ ing to identical components in the previous drawing figures are referred to by identical numeral references. In accordance with this embodiment, the wire consists of a strap 23 that is somewhat rigid and that is equipped with a coupling means at one it its ends, i.e. in accordance with this embodiment at the end turned towards the vehicle seat. An electric motor 24 mounted in the sid wall is arranged to displace the strap in the lengthwise direction thereof between the outer position illustrated in the drawing figure, in which position the coupling means of the strap cooperates with and engages in a corresponding attachment means 25 provided in the back of the vehicle seat, and a retracted position, release position, allowing free access to the rear seat of the vehicle between the seat back 3 and the vehicle door frame 26. Preferably, reel-in or retraction of the strap 23 is effected by winding it onto a strap reel-up mechanism 27 which is driven by the electric motor 24. Preferably, the strap is also tubular and provided with a stiffening spring. Numeral reference 28 designates a coupling tongue designed in a manner similar to the locking tongue on safety belts of the conventional type and the coupling part 25 arranged on the seat back preferably is formed with a funnel-shaped entrance mouth to allow the coupling tongue 28 to be safely guided into the mouth when the strap 23 is reeled out. By numeral 29 is designated a release lever which frees the back of the seat so that the latter may be folded forwards. Preferably, this lever may also serve to release the locking tongue and simultaneously, via an electric switch, to activate the motor 24 in such a manner that the free end of the strap 23 is reeled in. Prefer¬ ably, a second switch is provided which is activated when the seat back is folded back to the upright sitting posi- tion, whereby the motor 24 is made to reverse and thus guide the strap 23 back into the lock 25. Preferably, the supply of current to the motor 24 is then interrupted. In order to increase the yieldability of the strap 23 upon changes of the direction of inclination of the seat back or upon displacements forwards or backwards of the seat back, a limit switch may be provided to activate the motor 24 so that the strap is reeled out when the seat back is pushed forwards and reeled in when the seat back is pushed backwards. A simple modification of the embodiment illustrated in Fig. 6 would be to use a conventional safety belt and to mount the reel-up mechanism thereof in the vehicle side or in the back of the seat and the buckle in the seat back or the vehicle side, respectively. In this case, the strap may be connected manually. Although this modified embodiment clearly is surpassed by the automatically controlled device in accordance with Fig. 6, it should, however, be considered to be encompassed by the inventive idea. It is also possible to shift the device shown in Fig. 6 in such a manner that the strap storage means 27 together with the motor 24 are positioned in the seat back 3 and the coupling means 25 in the side of the vehicle. The invention is not limited to the embodiments described in the aforegoing and illustrated in the drawing figures merely by way of examples but it may be varied as to its details within the scope of the appended claims. For instance, it is quite possible to arrange the sleeve 13 otherwise than vertically in the side of the vehicle. It goes without saying that the device illus¬ trated in Fig. 6 could be coupled to the door lock of the vehicle or with other parts of the vehicle door in order to bring about the release state of that device.

Claims: CLAIMS 1. A safety device for vehicle seats, designed to lessen, in situations of heavy deceleration, the stress t which is exposed the means interconnecting the cushion (1 of the seat and the seat back (3), in particular in vehicle seats of the kind to the upper part of which is attached the upper belt part (6) of a safety belt (5), c h a r a c t e r i z e d in that it consists of an interconnection wire (10; 23) extending between the top of the seat back and the neighbouring side of the vehicle chassis and in such a way that it is yieldable during adjustment of the vehicle seat but locks in position in response to deceleration. 2. A safety device as claimed in claim 1, c h a r ¬ a c t e r i z e d in that at one of its points of attach¬ ment said wire (10; 23) is coupled to a wire storage device (13; 21; 27) which is yieldable during said adjustment of the vehicle seat but locks in position in response to deceleration. 3. A safety device as claimed in claim 2, c h a r ¬ a c t e r i z e d in that the interconnection wire (10) is of the same type as vehicle safety belts and that the wire storage device is of is of the same type as lockable car safety-belt reels (21). 4. A safety device as claimed in claim 2, c h a r ¬ a c t e r i z e d in that the wire storage device consists of a guide (13) mounted in the side of the vehicle in order to guide a runner (14) supported by the end part of the interconnection wire (10), and in that a latching means (15) is provided on said runner in order to lock the runner to the guide (13) when said deceleration situations arise. 5. A safety device as claimed in claim 4, c h a r ¬ a c t e r i z e d in that the latching means is a pivotable pawl (15) arranged to engage with said guide (13) and connected to an inertia body (17) which is sensitive to deceleration forces. 6. A safety device as claimed in claim 5, c h a r ¬ a c t e r i z e d in that the guide is in the form of an essentially vertically extending hollow profile member (13) which is mounted in the side of the vehicle, preferably in a rear side door, and in that the runner (14) is movable in the interior of said profile member, said pawl (15) arranged to engage with the inner face of said profile member. 7. A safety device as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that the wire (23) is removably secured at one of its attachment points. 8. A safety device as claimed in claim 1, c h a r ¬ a c t e r i z e d in that the wire (23) consists of a strap of some rigidity and a coupling member (28) at one of its ends, said wire arranged to be displaced in its lengthwise direction by means of an electric motor (24) between an outer position, the coupling position, in which the coupling member (28) of said strap is in engagement with the corresponding attachment (25), pre¬ ferably in the back of the vehicle seat, and a retracted position, the release position, in which free access to the rear seat of the vehicle is afforded between the seat back (3) and the door frame (26) of the vehicle. 9. A safety device as claimed in claim 8, c h a r ¬ a c t e r i z e d in that the control circuit of said electric motor (24) comprises switches positioned in conjunction with the seat adjustment controls. 10. A safety device as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that the means provided to lock the interconnection wire comprises controls incorporated in the vehicle electric circuit and preferably interconnected with the door lock.

Inventors: LINDBLAD LENNART, LINDBLAD, LENNART
Applicants: LINVENT AB
Application year: 1991
Main classification: B60R22
IPC codes: B60N2