Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2000-08-18
2002-08-20
Jillions, John M. (Department: 3654)
Winding, tensioning, or guiding
Reeling device
With spring motor
C280S805000, C280S806000, C180S268000
Reexamination Certificate
active
06435441
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a seatbelt retractor that takes up a seatbelt so as to be windable and extractable, and particularly relates to the technical field of a seatbelt retractor having a belt load restricting mechanism (hereafter also referred to as an “energy absorbing” or EA mechanism) which restricts the load placed on a seatbelt in the event of an emergency such as great vehicular deceleration occurring due to a collision or the like with the seatbelt being worn, by means of a torsion bar twisting and/or deforming.
BACKGROUND OF THE INVENTION
Conventionally, seatbelt devices provided to vehicles such as automobiles restrain the passengers with seatbelts in the event of emergencies such as described above, thereby preventing passengers from flying out of their seats, thus protecting the passengers.
Such seatbelt devices have seatbelt retractors for taking up the seatbelt. The seatbelt retractor is arranged so that if the seatbelt is not being worn the seatbelt is taken up on the spool, and if the seatbelt is worn, the seatbelt is extracted and worn by the passenger. Further the seatbelt retractor is arranged such that a lock mechanism operates in the event of an emergency such as described above which obstructs the rotation of the spool in the direction of extracting the seatbelt, thereby obstructing extracting of the seatbelt. Thus, the seatbelt restrains and protects the passenger in a sure manner in the event of an emergency.
With seatbelt retractors in conventional seatbelt devices, a great vehicular deceleration occurs at the time of the seatbelt restraining and protecting the passengers in an emergency such as a collision of the vehicle or the like. In this situation, great inertia moves the passengers forwards. Accordingly, a great load is placed on the seatbelt and the passenger is subjected to a great shock force from the seatbelt. This shock force on the passenger is not particularly a problem, but preferably should be restricted, if possible, in different circumstances.
Accordingly, conventional seatbelt retractors have been developed with a torsion bar, so as to restrict the load placed upon the seatbelt in the event of an emergency when the seatbelt is being worn.
FIG. 4
is a cross-sectional diagram illustrating an example of a seatbelt retractor having such a torsion bar. In the Figure, reference numeral
1
denotes a seatbelt retractor,
2
denotes a frame in the shape of a box with one end open,
3
denotes a seatbelt,
4
denotes a spool which is rotatably supported by both side walls of the frame
2
in the shape of a box with one end open and which takes up the seatbelt
3
,
5
denotes deceleration detecting means which detect greater vehicular deceleration generated in the event of an emergency such as described above and operates accordingly,
6
denotes a lock mechanism which operates due to the deceleration detecting means
5
and at least obstructs rotation of the spool
4
in the direction of extracting the seatbelt,
7
denotes a torsion bar which is movably fit and passed through the center of the spool
4
in the axial direction and which rotationally links the spool
4
and the lock mechanism
6
(this being equivalent to the seatbelt load restricting mechanism in the present invention),
8
denotes spring means for constantly pressing the spool
4
in the direction of taking up the seatbelt by the spring force of a spiral spring
9
via a bushing
10
,
11
denotes a pretensioner which generates belt take-up torque by operating in the event of an emergency such as described above, and
12
is a bushing for transmitting the seatbelt take-up torque from the pretensioner
11
to the spool
4
.
The lock mechanism
6
is provided with a locking base
14
(this being equivalent to the locking member in the present invention) which is capable of integrally rotating with a later-described first torque transmitting shaft
17
of the torsion bar
7
and holds a pawl
13
in a manner capable of locking, and the torsion bar
7
is provided with a lock gear
6
a
which normally integrally rotates with the torsion bar
7
but stops in the event of an emergency by the operation of the deceleration detecting means
5
and generates a relative rotational difference with the torsion bar
7
and engages the pawl
13
with inner teeth
19
on the side wall of the frame
2
so as to obstruct rotation of the locking base
14
, that is the spool
4
, in the direction of extracting the seatbelt. A male screw shaft portion
15
is formed to the locking base
14
, and a nut-shaped stopper member
16
which integrally rotates with the spool
4
is screwed to this male screw shaft portion
15
.
Also, a first torque transmitting portion
17
which engages the locking base
14
in a manner incapable of relative rotation is formed to the torsion bar
7
, and a second torque transmitting portion
18
is formed which engages the spool
4
in a manner incapable of relative rotation.
Then, the spool
4
is constantly pressed by the spring force of the spring means
8
in the direction of taking up the seatbelt, via the bushing
10
, torsion bar
7
, second torque transmitting portion
18
of the torsion bar
7
, and the bushing
12
. Also, in the event of the pretensioner
11
operating, the belt take-up torque generated at the pretensioner
11
is transmitted to the spool
4
via the bushing
12
, and thus the spool
4
takes up a predetermined
10
amount of the seatbelt
3
.
With conventional seatbelt retractors
1
thus configured, the seatbelt
3
is completely taken up by the pressing force of the spring means
8
when the seatbelt is not being worn.
Extracting the seatbelt
3
at a normal speed for wearing causes the spool
4
to rotate in the seatbelt extracting direction, which allows the seatbelt
3
to be extracted smoothly. An unshown tongue slidably provided to the seatbelt
3
is inserted to and retained by a buckle fixed to the vehicle body, following which the portion of the seatbelt
3
which has been excessively extracted is taken up by the spool
4
by the pressing force of the spring means
8
, and the seatbelt
3
is fit to the extent that the passenger does not feel too tight.
In the event of an emergency such as described above, the seatbelt take-up torque generated by the pretensioner
11
is transmitted to the spool
4
, and the spool
4
takes up the seatbelt
3
by a predetermined amount, thereby securely restraining the passenger. On the other hand, under great vehicular deceleration generated in the event of an emergency, the deceleration detecting means
5
operates and the lock mechanism
6
operates. That is, the rotation of the lock gear
6
a
in the direction of extracting the seatbelt is obstructed by the operation of the deceleration detecting means
5
, and the pawl
13
of the lock mechanism
6
rotates and engages the inner teeth
16
of the side wall of the frame
2
. This obstructs the rotation of the locking base
14
in the direction of extracting the seatbelt, so the torsion bar
7
is twisted, and the spool
4
alone rotates in the direction of extracting the seatbelt relatively to the locking base
14
. Subsequently, the spool
4
rotates in the direction of extracting the seatbelt while twisting the torsion bar
7
, so the load placed on the seatbelt
3
is restricted by the twisting torque of this torsion bar
7
, thus at least partially absorbing and alleviating the shock which the passenger is subjected to.
The relative rotation of the spool
4
as to the locking base
14
causes the stopper member
16
which integrally rotates with the spool
4
to relatively rotate as to the male screw shaft portion
15
to which it is screwed, and thus to move in the direction of the locking base
14
. Then, at the point that the stopper member
16
abuts against the locking base
14
, further rotation of the stopper member
16
is obstructed, so the rotation of the spool
4
is also obstructed, and twisting of the torsion bar
7
stops. Thus, the extracting of the seatbelt
3
is obstructed and the passeng
Fujii Hiroaki
Kajiyama Hiroshi
Jillions John M.
Takata Corporation
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