Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2003-04-25
2004-03-30
Jillions, John M. (Department: 3654)
Winding, tensioning, or guiding
Reeling device
With spring motor
Reexamination Certificate
active
06712306
ABSTRACT:
TECHNICAL FIELD
The invention relates to a coupling disc for a belt retractor of a vehicle safety belt.
BACKGROUND OF THE INVENTION
A coupling disc normally has a coupling catch which is pivotally mounted thereon so as to be movable between a position of rest and a coupling position.
The coupling disc is a generally known component of a locking mechanism by which a belt spool of the belt retractor can be locked so that no more safety belt can be withdrawn from the belt retractor. For the sake of completeness, such a locking mechanism is briefly described below with reference to FIG.
1
.
The belt retractor has a frame
10
, in which a belt spool
12
is rotatably mounted. The belt spool
12
is provided on at least one axial end with locking teeth
14
into which a locking catch
16
can be guided. The locking catch is pivotally mounted on the frame
10
. To move the locking catch, an actuating pin
18
is used, which engages into a recess
20
of the locking catch
16
and is securely arranged on a locking lever
22
. The locking lever
22
is pivotally arranged on the frame
10
turning about the same central axis C as the belt spool
12
. The locking lever
22
is biased by a restoring spring
24
into the position of rest shown in
FIG. 1
, in which the actuating pin
18
holds the locking catch
16
in its position of rest, in which it does not engage into the teeth
14
of the belt spool
12
. If, on the other hand, the locking lever
22
is rotated in the direction of the arrow A, i.e. clockwise with respect to
FIG. 1
, it guides the locking catch
16
into the locking teeth
14
of the belt spool
12
by means of the actuating pin
18
. The belt spool is then locked against a further rotation in the direction of the arrow A, i.e. in the belt band withdrawal direction.
The rotation of the locking lever
22
for the purpose of locking the belt spool is brought about by a rotation of the belt spool
12
in the belt band withdrawal direction, this rotation being firstly transferred to a coupling disc
26
which is connected with the belt spool
12
for joint rotation therewith, and from this disc to the locking lever.
When the locking mechanism of the belt retractor is activated in a belt band-sensitive manner, i.e. when the angular acceleration of the belt spool
12
, brought about by the belt band, exceeds a predetermined value, then a coupling catch
28
pivotally mounted on the coupling disc
26
is rotated out from its position of rest into a coupling position, in which it engages into coupling teeth
29
on the locking lever
22
. A conventional inertia disc (not illustrated in
FIG. 1
) may be used for pivoting the coupling catch
28
. When the coupling catch
28
is in its coupling position, a rotation of the belt spool is transferred via the coupling disc
26
, connected to the spool for joint rotation therewith, the coupling catch
28
arranged on the coupling disc, and via the coupling teeth
29
to the locking lever
22
which is entrained in the direction of the arrow A. In this way, the actuating pin
18
arranged on the locking lever
22
can guide the locking catch
16
into the locking teeth
14
of the belt spool
12
.
When the locking mechanism is triggered in a vehicle-sensitive manner, i.e. by exceeding an acceleration or deceleration acting on the vehicle and hence also on the belt retractor, a conventional inertia sensor (not illustrated) swivels an entrainment lever
30
from the position of rest shown in
FIG. 1
into an active position in which it engages into entrainment teeth
32
provided on the coupling disc
26
. The entrainment lever
30
is mounted on the locking lever
22
so that a rotation of the belt spool in the belt band withdrawal direction is transferred via the coupling disc
26
, the entrainment teeth
32
and the entrainment lever
30
to the locking lever
22
, whereby the locking catch
16
is guided by the actuating pin
18
into the locking teeth
14
of the belt spool
12
.
With the belt band-sensitive engaging of the locking mechanism, it is important that the values of the angular acceleration are reproducible, at which the locking mechanism responds. For safety reasons, specific values must not be fallen below. If, however, the locking mechanism responds unnecessarily early, this can lead to the locking mechanism already responding when the safety belt is put on normally, but somewhat jerkily. This is generally felt to be unpleasant.
The object of the invention consists in providing a coupling disc by which as precise a response of the locking mechanism as possible is ensured.
BRIEF SUMMARY OF THE INVENTION
According to the invention, a coupling disc for a belt retractor of a vehicle safety belt comprises a coupling catch which is pivotally mounted on the coupling disc so as to be movable between a position of rest and a coupling position. The coupling catch and the coupling disc are formed in one piece from plastic. A hinge section is provided between the coupling catch and the coupling disc. The invention is based on the knowledge that the engaging parameters of the locking mechanism are most able to be reproduced if the friction which acts between the parts then moving on engaging of the locking mechanism is avoided as far as possible. In contrast to the prior art, in which usually the coupling catch is mounted on a pin on the coupling disc, according to the invention a type of film hinge or a spring is provided. Apart from a negligible internal material friction, which takes place with a bending of the hinge section, the coupling catch is arranged so as to be free of friction on the coupling disc. The inherent elasticity of the hinge section, furthermore, has the advantage that a restoring spring for the coupling catch may possibly be dispensed with; a restoring spring also produces friction in the system. Furthermore, advantages are produced as regards the installation and the production costs. The coupling catch does not need to be produced, provided and installed as a separate component, but rather is automatically produced on manufacture of the coupling disc as a part connected in one piece therewith. In this way, in addition, any risk of faulty installation is eliminated. A further advantage consists in that with the manufacture in one piece, the otherwise unavoidable tolerance fluctuations are eliminated. The hinge section may be adapted in a simple manner to the respective requirements by its cross-section being suitably selected. With a correspondingly small cross-section, the coupling catch can have such an easy action that no additional inertia disc is necessary for its actuation; it is rotated into its coupling position solely by the inertia- and centrifugal forces which act on it with a corresponding angular acceleration of the coupling disc.
According to a preferred embodiment of the invention, provision is made that the hinge section runs in a curved shape and has a rectangular cross-section, the longer direction of which runs parallel to the swivel axis of the coupling catch. In this way, a slight bending resistance is produced for the swiveling of the coupling catch between the position of rest and the coupling position, however a very much higher bending resistance against an “undesired” deflection of the coupling catch transversely thereto.
Preferably, provision is made that the coupling disc has a support surface on which the coupling catch can rest when it is in the coupling position. As the hinge section can only transfer very small forces owing to its flexibility, the use of a support surface presents itself, in order to introduce the forces necessary for swiveling the locking lever on a short distance from the coupling disc via the coupling catch into the coupling teeth of the locking lever.
If no additional inertia disc is to be used for swiveling the coupling catch, provision is preferably made that on the coupling catch a weight element of metal is provided, for example a ball which is clipped into the coupling catch. In this way, the inertia- and centrifugal forces can be increased which i
Jillions John M.
Tarolli, Sundheim Covell & Tummino L.L.P.
TRW Occupant Restraint Systems GmbH & Co. KG
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