WO2004074052A1

WO2004074052A1 - A seat-belt retractor unit

Info

Publication number: WO2004074052A1
Application number: PCT/SE2004/000203
Authority: WO
Inventors: Jean-Philippe Leclercq; David Doucet; Thierry Jacqmarcq
Original assignee: Autoliv Development Ab
Priority date: 2003-02-24
Filing date: 2004-02-17
Publication date: 2004-09-02
Also published as: GB0304155D0; GB2398547A

Abstract

A seat-belt retractor unit (1) is disclosed, having a retractor reel (17) with a length of seat-belt (21) wound on it. A guide member (5) is provided which is mounted on the unit in a position with respect to the retractor reel (17) and which receives part of the seat-belt (21) to guide the seat-belt (21) and turn the seat-belt (21) through an angle as it is paid out from the retractor reel (17). The guide member (5) is mounted for rotation in a substantially pre-defined plane about an axis (36) substantially parallel to the direction in which the seat-belt extends from the retractor to the guide member.

Description

A SEAT-BELT RETRACTOR UNIT

THE PRESENT INVENTION relates to a seat-belt retractor unit, and more particularly relates to a seat-belt retractor unit suitable for installation in the upper part of a vehicle seat.

It is common practice, in the field of motor vehicle safety, to provide a vehicle seat with a seat-belt arrangement in which the seat-belt is wound on an inertia-type retractor reel. Since the seat-belt is paid out from the retractor reel in a direction substantially tangential to the retractor reel, it is common to provide a guide member arranged to guide the seat-belt and turn the seat-belt through an angle where the seat-belt exits the casing or trim mounted around the retractor assembly. Typically, a guide member of this type has been known to take the form of a roller mounted for rotation by a suitable frame structure. This type of arrangement is disclosed in DE4017321C2.

The prior specification teaches that retractor arrangements of the type disclosed above may be mounted integrally within the back rests of the seats of a motor vehicle, particularly the front seats. The guide member, although in the form of a rotatable roller, is not adjustable. It is an object of the present invention to provide an improved seat-belt retractor arrangement.

Accordingly, the present invention provides a seat-belt retractor unit having: a retractor reel with a length of seat-belt wound on it; and a guide member mounted on the unit in a position with respect to the retractor reel and receiving part of the seat-belt to guide the seat-belt and turn the seat-belt through an angle as it is paid out from the retractor reel, the guide member being mounted for rotation in a substantially predefined plane about an axis substantially parallel to the direction in which the seat-belt extends from the retractor to the guide member.

Preferably, said guide member is rotatably mounted to a support; and said seat-belt extends from said retractor reel and passes through a slot defined through the guide member.

Advantageously, said guide member comprises a metal disc rotatably mounted to said support via a rotational coupling; and a moulded plastic housing mounted to the disc, the seat-belt passing through both the disc and the housing.

Conveniently, said guide member is provided with at least one projection mounted to engage part of said support as the guide member is rotated, so as to limit the range of rotation of the guide member about said axis.

Preferably, the guide member is mounted so as to deflect out of said predefined plane when the seat-belt is subjected to a tensile load. Advantageously, said support is deformable and is configured to deform when the seat-belt is subjected to said tensile load, thereby moving the guide member out of said pre-defined plane.

Conveniently, the seat-belt retractor arrangement comprises at least one locking element, the or each locking element being mounted so as to be spaced from said guide member as the guide member rotates in said pre-defined plane, but to engage part of the guide member when the guide member is deflected out of said plane, thereby locking the guide member rotationally and preventing rotation of the guide member about said axis when the guide member is deflected out of said pre-defined plane.

Preferably, the or each said locking element is made of a material which mechanically deforms part of said guide member upon engagement with the guide member.

Advantageously, said guide member is provided with a plurality of locking formations, each said locking formation being arranged for engagement with a said locking element in a respective discreet rotational position of said guide member.

Conveniently, said locking formations are arranged substantially radially on said guide member.

Preferably, each said locking formation is a slot or recess.

Advantageously, the axis of rotation of said guide member is spaced from the seat-belt passing through the guide member. Conveniently the seat belt retractor arrangement is provided integrally on a vehicle seat.

So that the invention may be more readily understood, and so that further features thereof may be appreciated, an embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which-

FIGURE 1 is a perspective view of a seat-belt retractor unit located within an outer casing for installation on a vehicle seat;

FIGURE 2 is a schematic illustration, partly in vertical cross-section, through the retractor unit illustrated in Figure 1;

FIGURE 3 is a more detailed cross-sectional view, taken from the other side, of part of the seat-belt retractor unit of Figures 1 and 2;

FIGURE 4 is a side view of the seat-belt retractor unit illustrated in Figure 2; and

FIGURE 5 is a view corresponding generally to that of Figure 2, but illustrating the seat-belt retractor unit in an alternate deformed condition.

Referring initially to Figure 1, there is illustrated a seat-belt retractor unit 1 of a type particularly suitable for mounting integrally on a vehicle seat. The seat-belt retractor unit 1 comprises a moulded plastic outer casing 2 and is intended to be mounted in the upper region of a seat-back, substantially adjacent, but slightly above, the normal position of the shoulder of an occupant of the seat.

Inside the outer casing 2 (in the general region indicated at 3) the seat- belt retractor unit 1 comprises an inertia-type retractor reel of a type known per se. In the forward-most region of the outer casing 2, there is defined a circular aperture 4 within which is provided a rotatable disc-like guide member 5 which defines an exit slot 6 to allow for the passage therethrough of a length of seat- belt wound around the retractor reel, so that the seat-belt can be reeled on to the retractor reel and paid-out from the retractor reel through the slot 6. The disc may be rotated to adjust the angle at which the seat-belt may be guided as it exits from the retractor unit.

Turning now to consider Figure 2, the more detailed structure of the retractor unit 1 will be described.

Within the retractor unit 1 there is a retractor support frame 7 having a substantially horizontal base plate 8, a pair of spaced-apart side walls 9 (only one illustrated in Figure 2), and a substantially vertical front wall 10. The two side walls 9 extend upwardly from respective side edges of base plate 8, and the front wall 10 extends upwardly from the front edge of base plate 8, so as to lie between the two side walls 9.

One or more mounting apertures 11 are provided through the base plate 8 to allow the base plate 8 to be securely mounted, for example by way of bolts, to the frame of a seat-back rest (not illustrated). The uppermost edge of the front wall 10 is turned inwardly and terminates in a generally downwardly-depending lip 12 so as to define an upwardly facing substantially smoothly-curved guide surface 13.

A retaining bar 14 extends transversely between the two side walls 9 of the base frame 7, each end of the retaining bar 14 being received between a pair of opposing jaw-shaped projections 15 projecting rearwardly from each respective side wall 9. At a position above and adjacent the jaw-like projections 15, each side wall 9 defines an inclined support surface 16.

An inertia-type retractor reel 17 is mounted between the side walls 9 for rotation about a substantially horizontal axis.

A seat-belt guide 18 is mounted to the base frame 7 immediately adjacent and above the retractor reel 17. The seat-belt guide 18 defines an upwardly facing guide surface 19 which is spaced below a generally identical downwardly-facing guide surface 20.

The two guide surfaces 19,20 thus define between them a guide passage for the seat belt 21 which, as illustrated in Figure 2, is wound at one end around the retractor reel 17 such that the seat-belt 21 extends tangentially away from the retractor reel 17, passing through the guide passage defined between the guide surfaces 19, 20, so as to follow a path spaced substantially above the guide surface 13 defined by the inwardly-turned upper edge of the front wall 11.

The seat-belt guide 18 serves to limit the range of angles from which the seat-belt from which the seat-belt 21 is paid-out from the retractor reel 17 if the seat-belt is pulled from different directions, thereby ensuring that the seat-belt will not foul or otherwise catch on the retractor.

A support structure 22 is mounted on top of the base frame 7. The support structure 22 includes a support element 23 which extends generally upwardly and forwardly from the upper region of the base frame 7. The lowermost end of the support element 23 is received beneath the retaining bar 14 of the base frame 7 and bears against the support surface 16 defined by each side wall 8 of the base frame 7. In this way, the support 22 can very easily be mounted to the base frame 7 during manufacture of the retractor arrangement.

The lower region of the support element 23 merges with a bent or turned region 24 where it passes through a small angle, from where it extends upwardly and forwardly in a substantially linear manner, terminating at a point located substantially vertically above the front wall 10 of the base frame 7. At this position, the support element 23 turns through a relatively sharp bend 25 so as to extend generally downwardly. This generally downwardly-extending part of the support element 23 defines a deflection member 26 which is capable of deflecting about the bend 25 with respect to the main part of the support element 23. The lower end of the deflection member 26 is provided with an aperture 27 therethrough.

The support structure 22 i-urther comprises a pair of side plates 29 arranged on either side of the seat-belt 21 such that the seat-belt 21 passes between the two side plates 29. Each side plate 29 is secured along its rearmost edge to a respective edge of the support element 23. The lowermost region of each side plate 29 is provided with an outwardly-directed flange 30 which is secured via a respective bolt 31 (seen most clearly in Figure 4), to the inwardly- turned upper portion of the front wall 10 defining the guide surface 13.

Each side plate 29 carries a generally forwardly-projecting locking element 32 which terminates with a sharp point located in substantial alignment with the downwardly-extending deflection member 26, at a position spaced from the lower end of the deflection member 26. The pointed part of the locking element is made of a hard material.

A rotational coupling 33 having an axle 34 is mounted to the deflection member 26 such that its axle 34 extends through the aperture 27. An annular bush or bearing 35 is received on the axle 34 so as to abut the outermost face of the deflection member 26 around the aperture 27. The guide member 5 is then mounted (as described below) to the support structure 22 via the rotational coupling 32, such that the guide member is free to rotate about an axis of rotation 36.

The guide member 5 comprises a structural metal disc 37 having a central aperture sized to fit over the axle 34 such that the rear face of the metal disc 37 engages the bearing 35. In this way, the bearing 34 spaces the metal disc 37 from the deflection member 26. The guide member 5 is then held in place on the rotatable coupling 32 by a retaining pin clip 38 which is received within a transverse bore formed through the end of the axle 32.

The metal disc 37 is preferably made of steel and most preferably a soft steel so as to be mechanically deformable.

The metal disc 37 has an elongate, generally linear slot 39 formed through it at a position below and offset from the central aperture through which the axle 34 is received. At positions generally above the central aperture through which the axle 34 is received, the disc 37 is provided with a pair of spaced apart apertures 40. Each aperture 40 is offset from the axis of rotation 36 by an equal distance.

A moulded plastic housing 41 is mounted to the metal disc 37 around its periphery. The plastic housing 41 is moulded to define the exit slot 6 through the rotatable guide member 6, the exit slot 6 being aligned with the slot 39 formed through the metal disc 37. It will be seen from Figure 1 that the seat- belt 21 passes through the exit slot 6 and, by bearing against the plastic housing 41 in the region of the slot 6, serves to guide and turn the seat-belt 21 through an angle as it is paid-out from the retractor reel 17.

The plastics housing 41 of the rotatable guide member 5 is provided with a pair of integrally moulded elongate projections 42 which extend rearwardly from the housing 41 so as to pass through the apertures 40 formed in the metal disc 37. Each projection 42 extends past a respective side edge of the deflection member 26. The deflection member 26 thus passes between the two projections 42.

Turning now to consider briefly Figure 4, it will be seen that the rear surface of the metal disc 37 is provided with a plurality of locking formations 44. The locking formations 44 preferably take the form of spaced apart radially directed linear slots or recesses. In the initial configuration of the retractor arrangement illustrated in Figures 2 and 4, the locking formations 44 are spaced slightly from the locking elements 32 carried by the side plates 29.

It will therefore be understood from the foregoing description that in the configuration as illustrated in Figure 2, in which the deflection member 26 adopts an initial position in which it is substantially undeflected, the rotational coupling 33 serves to mount the guide member 5 such that the guide member 5 is rotatable relative to the support structure 22 about the axis 36. The axis of rotation 36 is arranged so as to be substantially parallel to the tangential path in which the seat-belt 21 is paid-out from the retractor reel 17 to the exit slot 6 in the guide member 5 where the seat-belt 21 is turned through an angle. Rotation of the guide member 5 about the axis 36 therefore enables the region of the seat-belt passing through the exit slot 6 to be oriented at any convenient angle across the torso of the seat occupant.

As the guide member 5 rotates to allow such orientation of the seat- belt 21, the projections 42 extending rearwardly from the housing 5, move with respect to the deflection member 26 located between them.

As the guide member 5 is rotated in this manner, a point will be reached at which one of the projections 42 engages and bears against one side edge of the deflection member 26, at which point further rotation of the guide member 5 in that direction will be prevented. The projections 42 therefore serve to limit the range of rotation of the guide member 5 between two predefined positions at which each projection 42 engages a respective side edge of the deflection member. This arrangement therefore prevents the guide member 5 rotating about the axis 36 to such a degree that the seat-belt 21, which passes through the guide member 5 at a position spaced from the axis 36, becomes twisted. It is clearly disadvantageous for the seat-belt 21 to become twisted because a twisted seat-belt would be unable to pass freely through the exit slot 6 which would therefore impede or prevent proper pay-out and retraction of the seat-belt 21 from and on to the retractor reel 17 respectively. It will be understood that in the event that a motor vehicle provided with the retractor arrangement 1 is subjected to a sudden deceleration (for example as a result of heavy breaking forces or as a result of a crash situation), the torso of a seat occupant will have a tendency to continue moving forwardly relative to the seat structure as a result of the torso's inertia. This forwards movement of the occupant's torso relative to the seat structure will apply a tensile load to the seat-belt 21, and the retractor reel 17 will lock. The supporting structure 22 of the retractor arrangement 1 is configured to deform under such conditions.

As will be seen from Figure 2, the exit slot 6 of a guide member 5 through which the seat-belt 21 passes, is spaced substantially from the bend 25 of the support structure 22. The application of the tensile load to the seat- belt 21 (for example in the direction illustrated by arrow 45 in Figures 2 and 5) therefore tends to deform the support structure 22 such that the deflection member 26 deflects out of its initial position illustrated in Figure 2 towards a deflected position as illustrated in Figure 5, in which it has moved towards the support element 23 through deformation of the bend 25.

Because the guide member 5 is rigidly mounted to the deflection member 26 by the rotational coupling 33, the guide member 25 is thus also deflected out of its initial pre-defined plane of rotation illustrated in Figures 2, 3 and 4, so as to adopt a deflected position illustrated in Figure 5. It will be seen from Figure 5 that in this, deflected state, the sharp locking elements 32 carried by each side plate 29 each become engaged with the rear face of the metal disc 37. In particular, it will be understood from Figure 4, that the locking elements 32 are arranged to engage respective locking formations 44 provided on the rear surface of the metal disc 37. This engagement between the locking elements 32 and respective locking formations 44 serves to lock the guide member 5 in a discrete rotational position, thereby preventing further rotation of the guide member 5 about the axis of rotation 36. This arrangement therefore prevents rotation of the guide member 5 when a substantial tensile load 45 is applied to the seat-belt 21, which thereby prevents the seat-belt 21 moving out of its restraining position across the torso of a seat occupant in a crash situation.

In certain embodiments of the present invention, it is envisaged that the metal disc 37 of the guide member 5, which is preferably made from soft steel, may be mechanically deformed by engagement with the sharp locking elements 32, such that the locking elements 32 become embedded in the material of the metal disc 37 thereby preventing further rotation of the guide member 5 when it is deflected out of its initial pre-defined plane of rotation.

When the tensile load 45 is subsequently removed from the seat-belt 21 (for example after the period of heavy braking or crash of the motor vehicle), the inherent resilience of the support structure 22 serves to return the deflection member 26 to its initial position illustrated in Figures 2 and 4, such that it again moves away from the support element 23. This movement therefore also returns the rotatable guide member 5 to its initial position illusfrated in Figures 2 and 4, which serves to disengage the locking elements 32 from the respective locking formations 44, thereby releasing the rotatable guide member 5 and permitting further rotation about the axis 36.

In a severe crash situation, the level of tensile load applied to the seat- belt 21 can be very considerable indeed, and in this type of situation, the support structure 22 of the retractor arrangement 1 is configured to deform more substantially so as to absorb some of the energy in the seat-belt 21 resulting from the crash. In such a situation, the support element 23 of the support structure 22 is configured to deform mechanically in the bent or turned region 24 in such a way that the support element 23 is deflected downwardly from the position illusfrated in Figure 5. If the tensile load 45 applied to the seat-belt 21 in a severe crash situation is high enough, the side plate 29 will also crumple and deform such that the entire support 22 moves generally downwardly towards the retractor reel 17. This deformation of the support structure 22 will, of course, result in the rotatable guide member 5 also moving downwardly such that the path through which the seat-belt 21 extends from the refractor reel 17 will be deflected significantly, such that the seat-belt 21 adopts a path as illusfrated in phantom in Figure 5. When the seat-belt 21 adopts this deflected path, it will be seen that the seat-belt 21 bears against the upwardly- facing guide surface 19 of the seat-belt guide 18 and also bears against the smoothly-curved guide surface 13 defined at the top of the front wall 10.

In the present Specification "comprises" means "includes or consists of and "comprising" means "including or consisting of.

Claims

CLAIMS:

1. A seat-belt retractor unit having: a retractor reel with a length of seat-belt wound on it; and a guide member mounted on the unit in a position with respect to the retractor reel and receiving part of the seat-belt to guide the seat-belt and turn the seat-belt through an angle as it is paid out from the refractor reel, the guide member being mounted for rotation in a substantially predefined plane about an axis substantially parallel to the direction in which the seat-belt extends from the retractor to the guide member.

2. A seat-belt retractor arrangement according to Claim 1, wherein said guide member is rotatably mounted to a support; and said seat belt extends from said retractor reel and passes through a slot defined through the guide member.

3. A seat-belt retractor arrangement according to Claim 2, wherein said guide member comprises a metal disc rotatably mounted to said support via a rotational coupling; and a moulded plastic housing mounted to the disc, the seat belt passing through both the disc and the housing.

4. A seat-belt retractor arrangement according to Claim 2 or Claim 3, wherein said guide member is provided with at least one projection mounted to engage part of said support as the guide member is rotated, so as to limit the range of rotation of the guide member about said axis.

5. A seat-belt retractor arrangement according to any preceding Claim, wherein the guide member is mounted so as to deflect out of said pre-defined plane when the seat belt is subjected to a tensile load.

6. A seat-belt retractor arrangement according to Claim 5, as dependant upon claim 2, wherein said support is deformable and is configured to deform when the seat-belt is subjected to said tensile load, thereby moving the guide member out of said pre-defined plane.

7. A seat-belt retractor arrangement according to Claim 5 or Claim 6, further comprising at least one locking element, the or each locking element being mounted so as to be spaced from said guide member as the guide member rotates in said pre-defined plane, but to engage part of the guide member when the guide member is deflected out of said plane, thereby locking the guide member rotationally and preventing rotation of the guide member about said axis when the guide member is deflected out of said pre-defined plane.

8. A seat-belt refractor arrangement according to Claim 7, wherein the or each said locking element is made of a material which mechanically deforms part of said guide member upon engagement with the guide member.

9. A seat belt refractor arrangement according to Claim 7 or Claim 8, wherein said guide member is provided with a plurality of locking formations, each said locking formation being arranged for engagement with a said locking element in a respective discreet rotational position of said guide member.

10. A seat belt retractor arrangement according to Claim 9, wherein said locking formations are arranged substantially radially on said guide member.

11. A seat belt retractor arrangement according to Claim 9 or Claim 10, wherein each said locking formation is a slot or recess.

12. A seat belt retractor arrangement according to any preceding Claim, wherein the axis of rotation of said guide member is spaced from the seat belt passing through the guide member.

13. A seat belt retractor arrangement according to any preceding Claim provided integrally on a vehicle seat.