GB2250419A

GB2250419A - Improvements in or relating to a pre-tensioner retractor reel

Info

Publication number: GB2250419A
Application number: GB9026341A
Authority: GB
Inventors: Leif Ennerdal
Original assignee: AUTOLIV SVERIGE AB
Current assignee: AUTOLIV SVERIGE AB
Priority date: 1990-12-04
Filing date: 1990-12-04
Publication date: 1992-06-10
Anticipated expiration: 2010-12-04
Also published as: GB2250419B; GB9026341D0

Abstract

A safety-belt retractor, for use in a motor vehicle, incorporates a pre-tensioning arrangement. The pre-tensioning arrangement is adapted to apply a tension to the safety-belt in the event that an accident arises. The pre-tensioning arrangement includes a shaft 3 on which the safety-belt may be wound, a wire 7 and means to connect the wire to the shaft to cause the shaft to wind in the safety-belt when tension is applied to the wire. An elongate power source 10 applies tension to the wire. The elongate power source is connected to the means supporting the shaft by a connection 11 which provides a predetermined degree of freedom of movement in at least one direction. This facilitates the mounting of the pre-tensioning device in a motor vehicle. <IMAGE>

Description

DESCRIPTION OF INVENTION "Improvements in or relating to a pre-tensioner retractor reel" THE PRESENT INVENTION relates to a pre-tensioner retractor reel, and more particularly to a pre-tensioner retractor reel intended for use in a motor vehicle.

A retractor reel is used with a safety-belt and is used to retract the safety-belt when not in use. It has been proposed to provide a pre-tensioner retractor reel which is adapted not only to retract the safety-belt when the safety-belt is not in use, but also to apply a tension to the safety-belt when accident conditions are sensed. If a tension is applied to a safety-belt in this way, the safety-belt will firmly hold the person wearing the safety-belt in their seat during the accident, thus minimising any risk of injury.

In particular, it has been proposed to provide a retractor reel with a wire or the like which is adapted to be operatively connected to the shaft of the retractor reel in order to rotate the shaft to wind-in safety-belt, the wire or the like being connected to a source of energy which applies a tension to the wire.

The source of energy may comprise a compression spring or may comprise a piston mounted within a cylinder which is associated with a pyrotechnic device. In either event the power source ma7 be relatively long.

It has been the practice to mount the pre-tensioning retractor in a motor vehicle with the elongate power source mounted within the lower part of the B"-post of the motor vehicle, that is to say the vertical part of the motor vehicle located between the front door of a vehicle and the rear door of the vehicle (although it is to be understood that the device may be mounted in an equivalent position in a two-door vehicle).

It has been found rather difficult to mount prior proposed pre-tensioning retractor reels in motor vehicles and, since the "B"-post of any particular vehicle does not necessarily have the same design as the "B"-post of another vehicle, it has been necessary to manufacture different retractor reel assemblies for use in different vehicles. This clearly represents a problem since different production lines have to be established for the different products.

The present invention seeks to provide an improved pre-tensioner retractor reel assembly.

According to this invention there is provided a pre-tensioning safety-belt retractor arrangement comprising means supporting a shaft upon which a safety-belt may be wound, a wire or the like and means operatively to connect the wire to the shaft to cause the shaft to wind-in safety-belt when tension is applied to the wire and means for applying tension to the wire comprising an elongate power source, the said elongate power source being connected to the means supporting the shaft by a connection which provides a predetermined degree of freedom of movement in at least one direction.

Preferably the connection provides freedom of movement in two orthogonal directions.

Conveniently the freedom of movement in one direction extends to approximately 100 on either side of a "norm" position in one direction.

Advantageously the freedom of movement in the other direction extends to approximately 50 on either side of a "norm" position in an orthogonal direction.

Preferably the said connection comprises a mounting element on the power source presenting a section of substantially rectangular cross-section which passes through a substantially rectangular aperture formed in a support plate mounted on the means supporting the shaft, the aperture having dimensions slightly greater than the corresponding dimensions of the said part of the support element.

Conveniently the power source comprises a pyrotechnic arrangement associated with a piston movable within a cylinder, the wire or the like being connected to the piston.

In order that the invention may be more readily understood and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which FIGURE 1 is a side view of a pre-tensioner retractor in accordance with the invention, FIGURE 2 is a front view of the pre-tensioner retractor of Figure 1, and FIGURE 3 is a vertical sectional view on the line III-III of Figure 1.

A retractor reel assembly in accordance with the invention comprises a mounting plate 1 provided with apertures 2 to receive fastening bolts or the like to secure the arrangement in position within a motor vehicle.

The mounting plate 1 forms part of a frame 2 which, as is conventional, supports a rotatable shaft 3 upon which a safety-belt 4 may be wound.

On one side of the frame 2 a housing 5 is provided which accommodates a mechanical locking device adapted to lock the shaft 3 in the event that an accident arises. There are many devices of this type known in the art.

On the other side of the frame, a housing 6 is provided which contains a spring adapted to impart a rotational bias to the shaft 3 to cause it to wind-in the safety-belt 4, as is conventional.

A wire (or cable) 7 enters the housing 6, as can be seen most clearly in Figure 3, where the wire is wound round three shoes 8 which form a clutch adapted to engage one end of the shaft 3 when a tension is applied to the wire 7 A clutch of this type is described in detail in European Publication 0361075, the contents of which are hereby incorporated into this Specification, and thus the clutch will not be described in detail here.

The wire 7 is connected to a piston element 0, which is movable within an elongate cylinder 10. The cylinder 10 is associated with a pyrotechnic device 11 adapted to inject gas into the cylinder 10 at a postion beneath the piston 9 in response to signals generated by an appropriate sensor when an accident arises.

It will thus be appreciated that, in the event that an accident arises, the pyrotechnic device 11 operates, injecting gas into the lower part of the cylinder 10, thus forcing the piston 9 to move upwards (as shown in Figure 3) along the axis of the cylinder 10, applying tension to the wire 7. The shoes 8 of the clutch then engage the shaft 3 and impart a rotarv motion to the shaft 3 tending to reel in the safety-belt 4 that is connected to the shaft 3. The mechanism within the housing 5 is adapted to permit the shaft to move to wind-in the safety-belt 4 under accident circumstances, but prevents any safety-belt from being paid out. As thus far described, the illustrated pre-tensioner retractor reel is conventional.

It is to be noted, however, that the cylinder 10 is relatively long and unwieldy. In the illustrated embodiment of the present invention a plate 12 is provided located between the frame 2 and the housing 6, the plate 12 extending above the rest of the housing and being provided with a portion defining a rectangular aperture 13. The cylinder 10 is supported on a mounting plate 14 which defines a finger 15 which extends through the aperture 13 in the plate 12. The finger 15 terminates with an upwardly directed lip 16.

The finger 15, as can be seen in Figure 3, is of rectangular cross-section, but the dimensions of the finger 15 are slightly less than the dimensions of the aperture 13. The arrangement is such that the elongate cylinder 10 may be moved substantially pivotally, with the finger 15 tilting within the aperture 13. As can be seen in Figure 2 the cylinder 10 can be moved pivotally through an angle of approximately 100 about a "norm" position in a plane which is parallel with the plane of the main part of the frame 1 and, as can be seen from Figure 1, the elongate cylinder 10 can move pivotally to an extent of approximately 60 in either direction about a norm position in a direction which is perpendicular to the plane defined by the plate 1.

Thus, the elongate cylinder 10 can move, relative to the rest of the retractor reel, to a predetermined extent, in two orthogonal directions.

This means that when the described retractor reel is being mounted in position in a motor vehicle the elongate cylinder 10 may be manipulated relative to the rest of the retractor reel to facilitate insertion of the elongate cylinder 10 into the "B"-post of a motor vehicle and also the elongate cylinder 10 may be mounted in any desired position (within its freedom of movement) relative to the rest of the retractor reel, thus enabling a single design of pre-tensioning retractor reel to be utilised in a large number of different motor vehicles.

The cylinder 10 may be provided with a clamp to be located in the region of the cylinder 10 identified by the reference numeral 17 in Figure 3 if desired.

Whilst the invention has been described with reference to one embodiment in which a particular connection is utilised between the cylinder and the rest of the retractor reel, other types of connection may be utilised which provide a similar degree of freedom of movement.

Whilst, in the described embodiment the power source is a pyrotechnic device and an associated piston and cylinder is to be appreciated that the power source may comprise a spring or other equivalent device.

Claims

CLAIMS:

1. A pre-tensioning safety-belt retractor arrangement comprising means supporting a shaft upon which a safety-belt may be wound, a wire or the like and means operatively to connect the wire to the shaft to cause the shaft to wind-in safety-belt when tension is applied to the wire and means for applying tension to the wire comprising an elongate power source, the said elongate power source being connected to the means supporting the shaft by a connection which provides a predetermined degree of freedom of movement in at least one direction.

2. An arrangement according to Claim 1 wherein the connection provides freedom of movement in two orthogonal directions.

3. An arrangement according to Claim 1 or 2 wherein the freedom of movement in one direction extends to approximately 100 on either side of a "norm" position in one direction.

4. An arrangement according to Claim 3 as dependent upon Claim 2 wherein the freedom of movement in the other direction extends to approximately 60 on either side of a "norm" position in an orthogonal direction.

5. An arrangement according to any one of the preceding Claims wherein the said connection comprises a mounting element on the power source presenting a section of substantially rectangular cross-section which passes through a substantially rectangular aperture formed in a support plate mounted on the means supporting the shaft, the aperture having dimensions slightly greater than the corresponding dimensions of the said part of the support element.

6. An arrangement according to any one of the preceding Claims in which the power source comprises a pyrotechnic arrangement associated with a piston movable within a cylinder, the wire or the like being connected to the piston.

7. A pre-tensioning retractor reel substantially as herein described with reference to and as shown in the accompanying drawings.

8. Any novel feature or combination of features disclosed herein.