Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2001-07-09
2003-03-11
Matecki, Kathy (Department: 3654)
Winding, tensioning, or guiding
Reeling device
With spring motor
C242S383500, C242S384600, C280S806000, C297S478000
Reexamination Certificate
active
06530536
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a webbing retractor which can impede pulling-out of a webbing at a time when a vehicle rapidly decelerates or the like, and in particular, to a webbing retractor which, after impeding pulling-out of a webbing, enables the webbing to be pulled out again.
2. Description of the Related Art
Generally, in a webbing retractor, a webbing is wound in a roll form on a hollow cylindrical spool (take-up shaft) supported at a frame which is formed in a substantial U-shape as seen in plan view and which is fixed to a vehicle. Usually, the webbing can be freely taken-up or pulled-out due to the spool rotating freely. Further, in the webbing retractor, a WSIR (webbing sensitive inertia reel) or a VSIR (vehicle sensitive inertia reel) is utilized in order to impede pulling-out of the webbing when a rapid deceleration of the vehicle or a rapid pulling-out of the webbing is sensed.
Hereinafter, a conventional webbing retractor equipped with a WSIR and a VSIR will be described on the basis of
FIGS. 12A and 12B
.
In
FIGS. 12A and 12B
, a webbing retractor
100
is shown in a side view seen from a rotational axis direction of a spool
102
. The webbing retractor
100
is formed to include the spool
102
; a lock plate
104
which is supported at the spool
102
so as to be freely swingable and which can mesh with ratchet teeth
106
provided at a frame (not shown); a V gear
108
which is provided coaxially with the spool
102
, and when relative rotation with respect to the spool
102
arises, the V gear
108
guides the lock plate
104
to a position at which engagement with the ratchet teeth
106
ismpossible; a W sensor portion
110
which forms the WSIR; and a V sensor portion
120
which forms the VSIR.
In this webbing retractor
100
, usually, the spool
102
and the V gear
108
rotate integrally. Thus, the webbing can be freely taken-up and pulled-out (the state shown in
FIG. 12A
) without the lock plate
104
engaging the ratchet teeth
106
.
On the other hand, when the webbing is pulled-out rapidly, an inertia plate
116
of the W sensor portion
110
cannot follow the rotation of the V gear
108
(the spool
102
) in the webbing pull-out direction (direction A in FIGS.
12
A and
12
B), and an inertial delay arises. As a result, relative rotation in the webbing take-up direction arises between the inertia plate
116
and the V gear
108
. A pawl
112
which abuts the inertia plate
116
is swung in the webbing take-up direction and engages with internal teeth
118
fixed to the frame, and rotation of the V gear
108
in the webbing pull-out direction is impeded (the state shown in FIG.
12
B).
When the rotation of the V gear
108
in the webbing pull-out direction is impeded, relative rotation is generated between the V gear
108
and the spool
102
which continues to rotate along with the pulling-out of the webbing. As a result, the lock plate
104
, which has a guide pin
104
a
which is inserted into a guide hole
108
a
formed in the V gear
108
, does not follow the rotation of the spool
102
, and is guided by the guide hole
108
a
via the guide pin
104
a
, and reaches a position at which engagement with the ratchet tooth
106
is possible (a position at which the lock plate
104
and the tooth tip of the ratchet tooth
106
engage). The lock plate
104
, which has been guided to the position at which engagement with the ratchet tooth
106
is possible, is guided to the tooth bottom of the ratchet tooth
106
by the configuration of the ratchet tooth
106
, and is set in a locked state. In other words, the lock plate
104
is self-locked, and rotation of the spool
102
in the webbing pull-out direction is impeded.
At the time of this self-locking, the lock plate
104
moves toward the tooth bottom of the ratchet tooth
106
(i.e., toward the left in FIGS.
12
A and
12
B). Accompanying this movement of the lock plate
104
, the guide pin
104
a
pushes the guide hole
108
a
side wall of the V gear
108
toward the left in
FIG. 12
, and due to this pushing moment, the V gear
108
rotates in the webbing take-up direction (direction B in FIGS.
12
A and
12
B). When the V gear
108
rotates by a predetermined amount in direction B, the engagement of the pawl
112
and the internal tooth
118
is cancelled. The pawl
112
, which is urged to swing in direction A by being connected to one end of a spring
114
whose other end is fixed to the V gear
108
, returns to its original position. In other words, the operation of the W sensor portion
110
is cancelled.
In this way, in the process in which the pulling-out of the webbing is impeded, operation of the W sensor portion
110
is cancelled. As a result, thereafter, pulling-out of the webbing is again possible. Note that, when the vehicle rapidly decelerates, tension of a predetermined value or more is applied to the webbing. Thus, while this tension is being applied, the state in which the lock plate
104
is engaged with the ratchet tooth
106
is maintained.
However, with the above-described conventional webbing retractor
100
, due to the guide pin
104
a
of the lock plate
104
pushing the side wall of the guide hole
108
a
of the V gear
108
, the V gear
108
is reversely rotated in the webbing take-up direction (direction B in FIGS.
12
A and
12
B), and the locking of the W sensor portion
110
is thereby cancelled. Thus, it is difficult to control the reverse rotation angle of the V gear.
Namely, if the reverse rotation angle of the V gear is too small, the amount of rotation of the V gear
108
in the webbing take-up direction is insufficient, and the locking of the W sensor portion
110
cannot be cancelled. On the other hand, if the reverse rotation angle of the V gear is too large, the pawl
112
engages with the next waiting internal tooth
118
and the locked state is maintained. Accordingly, accurate control of the V gear reverse rotation angle is required, and to this end, management of the dimensions of the guide hole
108
a
and management of the dimensions of the lock plate
104
and the like must be strictly carried out.
SUMMARY OF THE INVENTION
In view of the aforementioned, an object of the present invention is to provide a webbing retractor in which a webbing pull-out impeded state can be reliably cancelled, and in which control of a V gear reverse rotation angle is made easy.
In order to achieve the above object, a webbing retractor relating to the present invention comprises: a take-up shaft for taking-up, in roll form, a webbing for restraining a vehicle occupant; a frame which is fixed to a vehicle, and which rotatably supports both end portions of the take-up shaft, and at which a lock tooth is formed in a surface intersecting an end portion of the take-up shaft; a lock plate which is provided at at least one end portion side of the take-up shaft, and which is movable between a position of engagement with the lock tooth and a position of non-engagement with the lock tooth, and due to the lock plate engaging with the lock tooth, the lock plate impedes rotation of the take-up shaft in a webbing pull-out direction; a lock wheel provided coaxially with the take-up shaft at one end portion side of the take-up shaft, the lock wheel usually rotating integrally with the take-up shaft and holding the lock plate at the position of non-engagement, and when relative rotation arises between the lock wheel and the take-up shaft, the lock wheel moves the lock plate to the position of engagement; and a lock operation device having a pawl which is swingably supported and an engagement tooth which can engage with the pawl, the pawl usually being held at a position of non-engagement with the engagement tooth, and in a predetermined case, due to the pawl swinging and engaging with the engagement tooth, rotation of the lock wheel in the webbing pull-out direction is impeded, and due to the lock wheel being rotated in a webbing take-up direction, an engaged state of the pawl and the engagement tooth is cancelled, wherein a guide
Nagata Tomonori
Sumiyashiki Akira
Cole Thomas W.
Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho
Matecki Kathy
Nixon & Peabody LLP
Pham Minh-Chau
LandOfFree
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