GB1603057A

GB1603057A - Seat belt assembly for a vehicle

Info

Publication number: GB1603057A
Application number: GB15470/78A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-04-20
Filing date: 1978-04-19
Publication date: 1981-11-18
Also published as: ES244218U; SE413071B; FR2387661A1; DE2817128A1; ES244218Y; SE7704554L

Description

(54) SEAT BELT ASSEMBLY FOR A VEHICLE (71) 1, STIG MARTIN LINDBLAD, a Swedish Citizen, of 20, rue Saint-Pierre, CH-17()1, Fribourg, Switzerland, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a seat belt assembly for a vehicle.

When vehicles, for example passenger cars, have more than one row of seats but are equipped with doors for access at the front seats only, a problem may arise with the seat belts. It is undesirable that these belts when disconnected extend across the door opening in such a manner that getting in and out of the back seat is difficult or involves a risk of tripping. Retractor belts, in which the free parts are kept stretched by means of a spring loaded retractor device when the belt is not in use. exhibit this problem to a marked extent.

It has been possible to solve this problem by locating a lower attachment point of the belt at the rear of the door opening and locating a retractor device or an upper attachment point for the belt at the rear of the door opening at its top edge. By means of this arrangement the seat belt is stretched by the retractor device and extends in the form of a loop along the rear edge of the door opening or just behind that edge and does not obstruct the door opening itself. It has been found. however. that this position of the lower attachment point is not satisfactory for catching the body of the passenger in a collision. Therefore it is necessary to move the lower attachment point to a location in front of the rear edge of the door opening and in many countries. laws have been promulgated which require such a positioning relative to the seat of the vehicle, so that the fastening point will be positioned a considerable distance ahead of the rear edge of the door opening. With this arrangement the disconnected seat belt remains stretched across at least the bottom edge of the door opening and makes getting in and out of the vehicle difficult, with a serious risk of entanglement of the foot of the person trying to get out of the vehicle.

In order to remedy this disadvantage, it has been proposed that the lower end of the belt is attached to a pivotable arm. the pivoting point of which is within the accepted range of positions for the lower attachment point, i.e. ahead of the rear edge of the door opening. When the belt is fastened the arm can be pulled forwards and constitute a continuation of the belt and extend in alignment with the belt. With this arrangement the same conditions are obtained for a fastened belt, as if the belt itself is fastened at the pivoting point (which as stated is within the accepted range of positions for the lower attachment point).

When the belt is unfastened the arm can be pivoted backwards so that the lower end of the belt is positioned behind the rear edge of the door opening, and consequently is not stretched with any force of importance but only with the winding-up force. The propos al, in order to achieve that, is that the arm mentioned is spring loaded such that it is.

biased towards the rear position. When the belt is fastened the arm is pulled forwards to the forward position whilst it pivots back under the action of the spring on release of the belt. This arrangement has the disadvantages that the spring force must be of a certain magnitude in order to be capable of pivoting back the arm without being counteracted by the retraction force. Experience has shown that there is a risk that the force required for fastening the belt is not strong enough to pivot the arm forwards, so that it remains in its rear position. If this happens the protecting effect of the safety belt is eliminated as the arm, without any resist ance of importance in a collision or a sudden braking operation, pivots forwards, so that the seat belt cannot exercise its retaining force on the body of a passenger. In addition to the above there are also disadvantages because a spring device is difficult to produce such that it has values within the accepted tolerances and with a reasonable spring constant.

It is an object of the present invention to solve or ameliorate these problems by means of an assembly, which has a reliable function, and which does not require any special spring means but utilizes the spring force of the retractor device, which is already a feature of the seat belt assembly.

According to the present invention, there is provided a seat belt assembly for a vehicle comprising: a belt, an arm to one end of which one end of the belt is pivotally mounted, and an automatic retractor for thebelt, to which the other end of the belt is attached, the other end of the arm being adapted to be pivotally mounted adjacent a lower part of a seat of the vehicle such that the arm is adapted to rotate between a first position when the belt is in use and a second position when the belt is fully stowed; the assembly including first stopping means to limit retraction of the belt, whereby the extended length can be maintained at not less than the length when the belt is in its fully stowed position; the assembly also including second stopping means limiting rotation of the belt relative to the arm so as to prevent the belt from forming a straight line from the arm to an upper attachment point when the arm is in a position intermediate the first and second positions, and allowing the belt to form a straight line from the ann to the upper attachment point when the arm is in the second position: whereby in use. when a portion of the belt between the arm and an upper attachment point is unfastened from a securing point on the opposite side of the seat to the arm. the action of the retractor on the belt causes the arm to move from the first position to the intermediate position, the action of gravity on the arm then moving it from the intermediate position to the second position.

An embodiment of the present invention will now be described in detail, by way of example. with reference to the accompanying drawings, in which: Figures I and 2 show a seat of a vehicle equipped with a seat belt assembly embodying the present invention, viewed- from opposite sides of the seat; Figures 3 to 6 show, on an enlarged scale, the arm of the assembly in different positions of operation; and Figure 7 shows schematically the geometry, which serves as a basis for the function of the invention.

Referring to Figure 1 a seat 1 of a vehicle is located adjacent a door opening 2 of a vehicle equipped with front doors only.

When entering in order to occupy a seat located in a second row of seats behind the seat 1, the back-rest 3 of the seat 1 is let down in a forwards direction, so that entrance through the door opening 2 behind the seat is possible. In order to make this possible, the rear edge 4 of the door opening should be located behind the rearmost position of the seat 1.

The seat 1 is equipped with a seat belt 5, which via an arm 6 is attached to a lower attachment point 7, which at the same time functions as a pivot bearing for the arm 6.

The lower attachment point 7 is located within the approved range of positions ahead of the rear edge 4 of the door opening. The belt 5 extends from the arm 6 to a pivotable deflection fitting 8 at the upper attachment point, and from there further on to a retractor in the form of a reel device 9. A fastening tongue 10 is provided, slidable on the belt.

As shown in Figure 2, a fastening fitting 12 in the form of a buckle lock is supported by an arm 11 fixed to the floor of the vehicle, said lock being designed to hold the tongue 10 in a detachable grip. The tongue and the buckle lock can be substituted by a lock which catches the belt itself, a so called flap lock. It should also be mentioned that the retractor 9 may be positioned at the upper attachment point, in place of the deflection fitting 8, which then is eliminated.

The apparatus so far described is well known from the technique of safety belts. It is also a known fact that the arm 6 can be made pivotable to the position indicated with dashed and dotted lines in Figure 1, so that the belt 5 is pivoted away from the door opening in such a manner that the length of belt extending from the outer end of the arm 6 to the deflection fitting 8 is behind the rear edge 4 of the door opening. In the technique of the prior-art-this backwards pivoting of the arm is effected by means of a spring, as mentioned previously.

When the seat belt is fastened, the belt 5 extends from the outer end of the arm 6 across the lower part of the body of the wearer and is kept in place by means of the tongue 10 at the belt lock 12 and continues in a loop across the upper part of the body of the wearer back to- the side of the vehicle carrying the arm 6 where it passes through the deflection fitting 8 at the upper attachment point and then to the retractor 9. If the tongue 10 is released from the belt lock 12, the retractor 9 pulls the belt 5 so that it occupies a stretched position between the outer end of the arm 6 and the deflection fitting 8 at the upper attachment point. In the prior art it is required that the spring acting on the arm 6 overcomes the belt tension i.e. the winding-up force exerted by the retractor 9, in order to permit the arm to pivot fully back to the desired position with the belt behind the door opening. This is not so for the present invention.

In the Figures 3 to 5 the arm is shown in three different positions. As is evident from the figures, the belt 5 has a stiffened portion 13, which may comprise a number of seams sewn close to each other, and is pivotably connected by being introduced through a hole 14 at the outer end of the arm 6. The pivoting range, however, is to a certain extent limited by a fitting 15 (see also Figure 6). The fitting 15 comprises a ring 16, which can be rotated in the hole 14, and a cross-pin 17, which cooperates with a stop 18 on the arm 6. When the belt 5 is subjected to light forces only, it tends to occupy the pivotedout position illustrated in Figure 4 due to the fitting 15. When a strong tension is applied to the belt, such as when the belt is fastened, the pin 17 is pressed into the belt 5 and permits stretching of the belt 5 in line with the arm 6 as shown in Figure 3. Positions further pivoted-out beyond the position of Figure 4 can be occupied by the belt. under appropriately directed forces, see Figure 5.

The arm 6 has its centre of gravity positioned such that it tends to fall backwards (clockwise in Figure 1), when in connection with a movement in backwards direction it reaches approximately an upright position or even before that. when it still points somewhat forwards (to the left in Figure 1). This latter is brought about by the centre of gravity being behind the pivoting point 7.

A stop is provided, which prevents the belt 5 from being retracted by the retractor 9 more than will allow the belt to remain unstretched in the fully stowed position, when the arm is pivoted backwards, and which is indicated with dashed and dotted lines in Figure 1. The stop. which is not shown in the drawings, can be arranged as a seam on the belt, a washer, a rod or similar device attached to the belt stopping its winding-up on a reel in the retractor, or its passage through the deflection fitting 8, when the appropriate free length has been reached. Alternatively the retractor 9 itself can be provided with a mechanical stop, which limits the winding-up.

When the belt 5 is fastened, the arm 6 occupies the position shown in figure 3 (compare Figure 1). The arm 6 then forms a direct prolongation of the belt 5, so that both these elements form a straight line with each other.

This is obtained despite the stop fitting 15 tending to keep the belt in a swung-out position from the arm because the pin 17 is to some extent pressed into the belt, as is evident from Figure 3. In this position the device complies with all safety regulations, which prescribe that in connection with sudden forces any uncontrolled pulling-out of the belt cannot be permitted, and which control the position of the lower attachment point.

If, by way of example in connection with alighting, the belt 5 is released, the retractor 9 will pull the belt 9 through the deflection fitting 8, whereby the arm 6 is subjected to a backwards folding force, which raises the arm into the position illustrated in Figure 4.

In this position the stop is activated and any further tightening of the belt does not take place. As shown in Figure 4 the belt 5 in this position does not form a straight line with the arm 6, but describes a curve. This is brought about by the belt 5 yielding away from the pin 17, as the tensioning force in this position is considerably smaller than in the fastened condition according to Figure 3. In the positioning according to Figure 5 the centre of gravity of the arm 6 is behind the pivoting point 7, and therefore the arm on account of its own weight will pivot backwards to the position illustrated in Figure 5. This movement is permitted on account of the stop, and no tensioning of the belt takes place, until the backwards pivoted position is reached. Thus, the stop prevent= ing further retraction keeps avallable a sufficient free length of the belt to enable free movement between the position shown in Figure 4 and the position shown in Figure 5.

It may seem paradoxical that the required free length for the belt is the same in upright position of the arm (Figure 4), when the point of attachment of the belt 5 to the arm 6 is closest to the deflection fitting 8 at the upper attachment point, as in the backwards pivoted position (Figure 5). when the point of attachment of the belt 5 to the arm 6 is considerably further away from the upper attachment point. However, the condition in the first mentioned position is reached with the stiffened portion 13 and the yielding stop 15 making the arm 6. together with the stiffened portion 13 act as a curved arm in the upright position, i.e. by forcing the belt 5 to describe a curved line, while in the backwards pivoted position the arm 6 appears as a straight arm of shorter length, i.e. the belt 5 extends along a straight line.

By this arrangement the length of the belt 5 can be the same in the upright position and in backwards let-down position. This is evident, when looking at Figure 7. The lines and points, which relate to the previously mentioned details. have got the same reference numerals as before. Of the lengths indicated, A stands for the length of the arm 6 and B for the length of the stiffened portion 13. C and D respectively indicate the straight length of the belt 5 in upright position and in backwards swung position respectively. In order to obtain the function, it is required that the length B plus C in the upright position, in which the centre of gravity of the arm 6 is behind its pivoting point 7, is as long as the length D, which is the length of the straightened-out belt 5 from the backwards pivoted arm 6 to the deflection fitting 8. Practical tests have proved that this condition may be obtained with the device illustrated in the drawings.

The length of the stiffening portion and its pivoted-out position can be adjusted appropriately to different locations of the centre of gravity of the arm 6. A centre of gravity located far back thus means that the arm 6 need not be pivoted up so much in order to tilt over, whereby the length of the stiffening portion can be made smaller than in connection with a more forwards located centre of gravity. It is also possible to make the arm 6 curved in order to contrive that it gocs clear of the lower rear corner of the door opening.

When fastening the safety belt. the tongue 10 is moved into engagement with the belt lock 12. in the customary manner. This pulls out the belt 5. and this results in the arm 6 pivoting over to the position illustrated in Figure 3. Because of the fact that it is not spring loaded. as is the case in the devices of the prior art. the arm 6 is easily pivotable. In the pivoting movement in forwards direction the fitting 15 serves as a stop. so that the arm does not fall too far forwards but occupies a position suitable for fastening the belt.

WHAT I CLAIM IS: I. A seat belt assembly for a vehicle comprising: a belt. an ann to one end of which one end of the belt is pivotally mounted, and an automatic retractor for the belt, to which the other end of the belt is attached. the other end of the arm being adapted to be pivotally mounted adjacent a lower part of a seat of the vehicle such that the arm is adapted to rotate between a first position when the belt is in use and a second position when the belt is fully stowed: the assembly including first stopping means to limit retraction of the belt. whereby the extended length can be maintained at not less than the length when the belt is in its fully stowed position: the assembly also including second stopping means limiting rotation of the belt relative to the arm so as to prevent the belt from forming a straight line from the arm to an upper attachment point when the arm is in a position intermediate the first and second positions, and. allowing the belt to form a straight line from the arm to the upper attachment point when the arm is in the second position; whereby in use, when a portion of the belt between the arm and an upper attachment point is unfastened from a securing point on the opposite side of the seat to the arm. the action of the retractor on the belt causes the arm to move from the first position to the intermediate position, the action of gravity on the arm then moving it from the intermediate position to the second position.

2. A seat belt assembly according to Claim 1, wherein the belt. at a position intermediate the arm - and the retractor, passes through an attachment means adapted to be positioned at the upper attachment point, and the first stopping means is a projection provided on the belt which abuts against the attachment means when the extended length of the belt is equal to its length when fully stowed.

3. A seat belt assembly according to Claim 1 or Claim 2 wherein the belt has a stiffened portion proximate to the arm.

4. A seat belt assembly according to any one of the preceding claims. wherein a resilient bias between the second stopping means and the belt is overcome when the arm is in its said first position, so that the belt is substantially aligned with the arm.

5. A seat belt assembly according to Claim 4 wherein the resilient bias is formed by deformation of the belt by a stop surface of the second stopping means.

6. A seat belt assembly for a vehicle substantially as herein described with reference to and as illustrated in the accompanying drawings.

7. A vehicle having a seat belt assembly according to any one of the preceding claims. in which the arm is pivotally mounted adjacent a lower part of the vehicle. the belt is connected to an upper attachment point above the seat and on the same side of the seat as the arm, and connecting means are provided on the opposite side of the seat to the arm. the belt, intermediately between the arm and the upper attachment point being connectable to the connecting means to fasten the belt.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

indicated, A stands for the length of the arm 6 and B for the length of the stiffened portion 13. C and D respectively indicate the straight length of the belt 5 in upright position and in backwards swung position respectively. In order to obtain the function, it is required that the length B plus C in the upright position, in which the centre of gravity of the arm 6 is behind its pivoting point 7, is as long as the length D, which is the length of the straightened-out belt 5 from the backwards pivoted arm 6 to the deflection fitting 8. Practical tests have proved that this condition may be obtained with the device illustrated in the drawings.

The length of the stiffening portion and its pivoted-out position can be adjusted appropriately to different locations of the centre of gravity of the arm 6. A centre of gravity located far back thus means that the arm 6 need not be pivoted up so much in order to tilt over, whereby the length of the stiffening portion can be made smaller than in connection with a more forwards located centre of gravity. It is also possible to make the arm 6 curved in order to contrive that it gocs clear of the lower rear corner of the door opening.

When fastening the safety belt. the tongue 10 is moved into engagement with the belt lock 12. in the customary manner. This pulls out the belt 5. and this results in the arm 6 pivoting over to the position illustrated in Figure 3. Because of the fact that it is not spring loaded. as is the case in the devices of the prior art. the arm 6 is easily pivotable. In the pivoting movement in forwards direction the fitting 15 serves as a stop. so that the arm does not fall too far forwards but occupies a position suitable for fastening the belt.

WHAT I CLAIM IS: I. A seat belt assembly for a vehicle comprising: a belt. an ann to one end of which one end of the belt is pivotally mounted, and an automatic retractor for the belt, to which the other end of the belt is attached. the other end of the arm being adapted to be pivotally mounted adjacent a lower part of a seat of the vehicle such that the arm is adapted to rotate between a first position when the belt is in use and a second position when the belt is fully stowed: the assembly including first stopping means to limit retraction of the belt. whereby the extended length can be maintained at not less than the length when the belt is in its fully stowed position: the assembly also including second stopping means limiting rotation of the belt relative to the arm so as to prevent the belt from forming a straight line from the arm to an upper attachment point when the arm is in a position intermediate the first and second positions, and. allowing the belt to form a straight line from the arm to the upper attachment point when the arm is in the second position; whereby in use, when a portion of the belt between the arm and an upper attachment point is unfastened from a securing point on the opposite side of the seat to the arm. the action of the retractor on the belt causes the arm to move from the first position to the intermediate position, the action of gravity on the arm then moving it from the intermediate position to the second position.
2. A seat belt assembly according to Claim 1, wherein the belt. at a position intermediate the arm - and the retractor, passes through an attachment means adapted to be positioned at the upper attachment point, and the first stopping means is a projection provided on the belt which abuts against the attachment means when the extended length of the belt is equal to its length when fully stowed.
3. A seat belt assembly according to Claim 1 or Claim 2 wherein the belt has a stiffened portion proximate to the arm.
4. A seat belt assembly according to any one of the preceding claims. wherein a resilient bias between the second stopping means and the belt is overcome when the arm is in its said first position, so that the belt is substantially aligned with the arm.
5. A seat belt assembly according to Claim 4 wherein the resilient bias is formed by deformation of the belt by a stop surface of the second stopping means.
6. A seat belt assembly for a vehicle substantially as herein described with reference to and as illustrated in the accompanying drawings.
7. A vehicle having a seat belt assembly according to any one of the preceding claims. in which the arm is pivotally mounted adjacent a lower part of the vehicle. the belt is connected to an upper attachment point above the seat and on the same side of the seat as the arm, and connecting means are provided on the opposite side of the seat to the arm. the belt, intermediately between the arm and the upper attachment point being connectable to the connecting means to fasten the belt.