Safety belt arrangement

Details Safety belt arrangement Safety belt arrangement

1999-02-11

2001-01-09

Dickson, Paul N. (Department: 3618)

Land vehicles

Wheeled

Attachment

C297S480000

Reexamination Certificate

active

06170876

ABSTRACT:

BACKGROUND OF THE INVENTION
The invention relates to a safety belt arrangement with a holder which can be fastened to a vehicle part and which journals a guide roller between two bearings, with at least one band part of the belt band which partially wraps around the guide roller extending at an inclination to the axis of rotation of the guide roller in the fastened state.
Roller guides are basically known in various variants. Safety belt arrangements of this kind are used in motor vehicles in order to deflect the belt band which is unwound from a belt roller in the direction towards the passenger.
FIG. 8
shows a roller guide for a safety belt which has a holder
10
of metal which is approximately oval in a plan view and in which a cut-out
11
which is basically rectangular and upwardly open is provided for a guide roller
22
. Above the cut-out
11
a circular opening
12
for the fastening of the holder
10
to a vehicle is provided centrally in the holder
10
. A shaft
20
is rotatably fastened between two bearings in order to be able to rotate the guide roller
22
in a friction-poor manner when the belt band
14
, which is guided around the guide roller
22
, is moved, for example in order to put on the safety belt.
In the fastened state of this safety belt arrangement, that is, when the safety belt
14
has been put on by a passenger, the safety belt
14
partially wraps around the guide roller
22
. In this the band part B of the belt band
14
extends at an inclination to the axis of rotation of the guide roller
22
in the situation illustrated in FIG.
8
. The band part A of the belt band
14
extends at right angles to the axis of rotation of the guide roller
22
. In addition to the situation illustrated in
FIG. 8
, however, in the fastened state both band parts A and B of the belt band
14
can also extend at an inclination to the axis of rotation of the guide roller
22
.
The inventors of the present application have recognised that in a safety belt arrangement such as is shown in
FIG. 8
, the belt band
14
is no longer correctly guided via the guide roller
22
at higher belt forces but rather is transported laterally (to the right in
FIG. 8
) as a result of the skewing present between the belt band parts A and B. This can have the result that the resulting force of the belt band
14
runs out of the axis of rotation of the holder
10
, so that the guide fitting executes an undesirable and abrupt movement. In this the belt band can be completely pulled into a corner of the deflection, which can impair the correct functioning of the safety belt arrangement, in particular when additional safety devices such as belt tighteners are provided.
SUMMARY OF THE INVENTION
The problem (object) underlying the invention is to provide a safety belt arrangement of the initially named kind in which a correct deflection of the belt band about the guide roller is ensured even at increased belt forces.
This object is satisfied by the features of claim
1
and in particular in that the journalling of the guide roller is designed elastically and in that a brake device is provided which enters into engagement with the guide roller at increased belt forces. A brake device of this kind can for example be formed in that the shaft on which the guide roller is journalled or the bearings on which the shaft is journalled are designed elastically.
Through the brake device provided in accordance with the invention the guide roller is braked or completely blocked at increased belt speeds, through which a lateral transport of the belt band on the guide roller is avoided. Since a skewed belt band which is guided around a guide roller is laterally transported during the application of a drawing force only when very large belt forces are present and when the guide roller can rotate, the brake device provided in accordance with the invention prevents an undesirable lateral transport of the belt band in an effective manner. The brake device is preferably released from engagement when the belt forces let up so that in this case the guide roller can again rotate freely.
Advantageous embodiments of the invention are described in the description, in the drawings and in the subordinate claims.
The safety belt arrangement in accordance with the invention has at least one, preferably two resiliently executed bearings, through which it is ensured that forces which are exerted on the safety belt—and thus also on the guide roller or the bearings respectively—are first taken up by the resiliently executed bearing. When large forces arise, the bearing deforms elastically to such an extent that the guide roller is pressed against an abutment or the like so that the rotational movement of the guide roller is braked or stopped respectively. Subsequently the belt band can slide over the braked guide roller without a transverse movement arising in the region of the guide roller.
In accordance with a further advantageous embodiment the bearing can have a sleeve-like shape and be open at one end and closed at an opposite end, through which a simple manufacture is possible. The bearing can be manufactured by an injection moulding or an extrusion process.
In a third preferred embodiment of the invention the bearing can be widened at the outer periphery of the open end, through which the bearing can be reliably held by the widened edge in an aperture of the holder and a sliding in of the bearing into the aperture is excluded.
In a further embodiment the bearing can have at the open end a plurality of slit-like or conical cut-outs extending in the axial direction that is parallel to the axis of rotation of the guide roller, which are preferably arranged to lie opposite one another. Through this the bearing can be compressed slightly at the open end and can be pressed into an aperture in the holder in the axial direction, through which its installation is facilitated.
A good spring action for a shaft results in accordance with a further advantageous embodiment of the invention if the bearing is inserted into an aperture in the holder which is executed as a passage bore. In this case the bearing has a free space in order to be resilient in the axial direction.
In accordance with a further embodiment of the invention the bearing can have a convex bearing surface at the closed end and in the interior which is preferably arranged concentrically at an inner end face. The contact surface of the guide roller or its shaft respectively in the bearing is thereby minimised, and through the point contact between the shaft end and the bearing the frictional forces can be considerably reduced. Through the low wear arising which is connected therewith, a long lifetime of the bearing is furthermore ensured.
In accordance with a preferred embodiment the bearing can be made cylindrical and have at least two regions with different diameters. Furthermore, the bearing can have the larger diameter at the side of the open end and preferably form a contraction after about one half its length. The bearing can also have a section of varying diameter-shaped cross-section between the two regions of different diameter, with a good spring action being achieved through this special shaping of the bearing. The section of varying diameter can at least partially extend inside the region with the greater diameter.
It is advantageous if the bearing lies with the outer surface of the region with the greater diameter in contact with a wall of the aperture of the holder. Through this a good area contact with the holder is possible, through which a high and uniform force transmission can take place.
The bearing can preferably consist of a plastic, e.g. of polyoxymethylene, which preferably has a Teflon reinforcement. Through the high cristallinity, the construction material polyoxymethylene (POM) can be machined to a very hard, stiff, percussion-tough and abrasion-proof bearing. The strength and stiffness of the material can be further increased with a glass fibre reinforcement, and the abrasion resistance can be further increased by an alloying in of e

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