Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2000-03-24
2001-10-23
Walsh, Donald P. (Department: 3653)
Winding, tensioning, or guiding
Reeling device
With spring motor
C242S383500
Reexamination Certificate
active
06305633
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a webbing take-up device equipped with locking means which prevents rotation of a winding shaft in a direction in which a webbing is pulled out at the time of sudden deceleration of a vehicle.
2. Description of the Related Art
FIG. 9
schematically shows a locking structure of a conventional webbing take-up device
150
. As illustrated in this figure, the webbing take-up device
150
includes a frame
152
and the frame
152
is fixed to the side of a vehicle body. An internal gear ratchet
156
is formed in a leg plate
154
which is one of leg plates provided in the frame
152
. At the side of an inner periphery of the internal gear ratchet
156
, a pair of lock plates
158
and
160
each having a substantially crescent-shaped plate are disposed in such a manner as to be substantially point-symmetrical about the center of the internal gear ratchet
156
. Locking teeth
158
A and
160
A are formed respectively in portions of outer peripheries of the lock plates
158
and
160
and face a ratchet gear
156
A of the internal gear ratchet
156
.
Further, engagement concave portions
162
and
164
are formed respectively in intermediate portions of the pair of lock plates
158
and
160
, and a branched portion
166
A of a winding shaft
166
projecting from an axial core portion of the internal gear ratchet
156
is disposed in the engagement concave portions
162
and
164
.
Moreover, a V gear
168
rotating by following the winding shaft
166
is provided at a position adjacent to the internal gear ratchet
156
. Lock teeth
168
A are formed in the outer periphery of the V gear
168
, and four guide holes
170
and
172
are formed substantially at ends of an axial core portion of the V gear
168
. A pair of projections
158
B projecting from the lock plate
158
and a pair of projections
160
B projecting from the lock plate
160
are inserted respectively in the guide holes
170
and the guide holes
172
.
According to the above-described structure, when sudden deceleration of a vehicle is detected by an acceleration sensor (not shown), a pawl of a sensor lever of the acceleration sensor is engaged with the lock tooth
168
A of the V gear
168
to thereby prevent rotation of the V gear
168
in a direction in which a webbing is pulled out. For this reason, relative rotation is caused between the winding shaft
166
which is about to rotate in the direction in which the webbing is pulled out due to webbing tension generated by inertia movement of a vehicle occupant, and the V gear
168
which is prevented from rotating in the direction in which the webbing is pulled out. For this reason, the projections
158
B and
160
B are guided by the guide holes
170
and
172
of the V gear
168
(so as to respectively move in the guide holes
170
and
172
), and the pair of lock plates
158
and
160
are moved in directions apart from each other to allow the lock teeth
158
A and
160
A to be engaged with the ratchet gear
156
A of the internal gear ratchet
156
. As a result, as illustrated in
FIG. 9
, the rotation of the winding shaft
166
in the direction in which the webbing is pulled out is prevented and the webbing take-up device is thereby placed in a locked state.
The above-described locking structure conventionally used widely is provided to maintain lock strength by using two lock plates
158
and
160
. However, the number of parts increases for the reason that the two lock plates
158
and
160
are used, and an increase in the weight of the webbing take-up device
150
is thereby caused.
SUMMARY OF THE INVENTION
In view of the above-described facts, an object of the present invention is to provide a webbing take-up device of which weight can be reduced with lock strength thereof being maintained.
A first aspect of the present invention is a webbing take-up device comprising a frame supported at the side of a vehicle body, a winding shaft rotatably supported by the frame and taking up a vehicle occupant-restraining webbing, and locking means for preventing rotation of the winding shaft in a direction in which the webbing is pulled out at the time of sudden deceleration of a vehicle, the locking means including: a first lock portion disposed coaxially with the winding shaft and rotating by following the winding shaft, the first lock portion being prevented from rotating in a direction in which the webbing is pulled out at the time of sudden deceleration of the vehicle; a second lock portion disposed coaxially with the winding shaft and rotating integrally with the winding shaft, the second lock portion causing relative rotation between the first lock portion and the second lock portion when rotation of the first lock portion in the direction in which the webbing is pulled out is prevented; a third lock portion which is held by the second lock portion in such a manner as to be movable in a first direction, and when the relative rotation between the first and second lock portions is caused, which moves in the first direction, the third lock portion being comprised of a single component having lock teeth; a fourth lock portion provided in the frame and having lock teeth which are engaged with the lock teeth of the third lock portion when the third lock portion moves in the first direction; and a guide portion which, when the lock teeth of the third lock portion is engaged with the lock teeth of the fourth lock portion, utilizes reaction force generated by engagement between the lock teeth of the fourth lock portion and the lock teeth of the third lock portion so as to displace a predetermined portion of the second lock portion in a direction in which the second lock portion moves close to a predetermined portion of the fourth lock portion, thereby allowing engagement between the predetermined portion of the second lock portion and the predetermined portion of the fourth lock portion, wherein the first direction is that in which the lock teeth of the third lock portion moves close to the lock teeth of the fourth lock portion.
In accordance with a second aspect of the present invention, the predetermined portion of the fourth lock portion is a portion provided substantially symmetrical with an engaging portion of the fourth lock portion engaged with the lock teeth of the third lock portion with respect to a rotational axis of the second lock portion, and the predetermined portion of the second lock portion is provided to face the predetermined portion of the fourth lock portion.
In accordance with a third aspect of the present invention, the third lock portion is held by a holding portion formed in the second lock portion, the holding portion having a wide portion, and includes a protruding portion extending in a second direction at one end thereof and lock teeth at another end thereof, a dimension of the wide portion in the second direction is substantially equal to an overall dimension of a dimension of the protruding portion in the second direction and a dimension of the one end in the second direction, and the second direction is substantially perpendicular to the first direction.
In accordance with a fourth aspect of the present invention, the guide portion includes a bearing portion for supporting the second lock portion, and when the bearing portion deforms due to the reaction force, the guide portion allows the predetermined portion of the second lock portion to be engaged with the predetermined portion of the fourth lock portion.
In accordance with a fifth aspect of the present invention, each strength of the third lock portion and the fourth lock portion is greater than that of the second lock portion, and when the lock teeth of the third lock portion are engaged with the lock teeth of the fourth lock portion, the predetermined portion of the second lock portion plastically deforms so as to be engaged with the predetermined portion of the fourth lock portion.
According to the present invention, at the time of sudden deceleration of a vehicle, the first lock portion disposed coa
Asagiri Katsuki
Sumiyashiki Akira
Cole Thomas W.
Jones David A
Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho
Nixon & Peabody LLP
Walsh Donald P.
LandOfFree
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