Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2001-11-27
2004-05-11
Rivera, William A. (Department: 3654)
Winding, tensioning, or guiding
Reeling device
With spring motor
Reexamination Certificate
active
06732969
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a seatbelt retractor for use in a passenger car, etc., in order to ensure the safety of a vehicle occupant.
The seatbelt retractor must be installed in order to ensure the safety of a vehicle occupant upon an accident, such as a passenger car collision, and various types thereof have been developed. An example of the simplest structure thereof is shown in FIG.
11
.
A spring cover
21
, which is a supporter at one side of the seatbelt retractor, is provided with a bearing
21
a
arranged therein, into which a shaft
22
a
of a spool
22
is fitted so as to rotate while an urging force in the retracting direction is applied to the shaft
22
a
by a spring. Around the spool
22
, a seatbelt is wound.
Inside the spool
22
, a concave fitted portion (not shown) is formed, into which one end of a torsion bar
23
is fitted. The other end of the torsion bar
23
is fitted into a concave fitted portion (not shown) formed in a locking base
24
. A shaft
24
a
of the locking base
24
passes through a hole
25
a
of a lock gear
25
so as to fit into a bearing (not shown) of a retainer
26
, which is a supporter in the other side of the seatbelt retractor.
Such a mechanism results in supporting the spool
22
at its rotating shaft by the spring cover
21
and the retainer
26
, and rotating the spool
22
so as to retract the seatbelt by means of the urging force of the spring. The spring cover
21
and the retainer
26
are fixed at both ends of a base frame
28
, so that the spool
22
is accommodated within the base frame
28
.
In these structural elements, the locking base
24
and the lock gear
25
are relatively rotatable by a predetermined angle, so that the lock gear
25
is urged by a spring
29
relative to the locking base
24
in the direction of extracting the seatbelt so as to approach the limit of the relative rotation.
When the seatbelt is extracted in a normal state, since there is no rotational resistance against the lock gear
25
, the lock gear
25
can not overcome the urging force of the spring
29
to thereby rotate integrally with the locking base
24
.
Even when the locking base
24
is rotated in the retracting direction as the spool
22
is rotated by the spring force, the lock gear
25
rotates integrally with the locking base
24
because the lock gear
25
is designed originally to approach the limit of the rotation relative to the locking base
24
in this direction as mentioned above.
When rapid extraction of the seatbelt is produced due to a collision or the like, a flywheel
30
accommodated within the lock gear
25
is displaced by overcoming the urging force of a spring
31
, so that the lock gear
25
can not rotate relatively to the retainer
26
and the rotation is stopped.
Then, the rocking base
24
rotates relatively to the lock gear
25
against the urging force of the spring
29
. A mechanism is constructed such that a pawl
32
accommodated in the locking base
24
protrudes outside by this relative rotation, and a gear of the externally protruded pawl
32
is brought into engagement with a gear section
28
a
formed in the base frame
28
, thereby also stopping the rotation of the locking base
24
.
Accordingly, rotation of the torsion bar
23
is also stopped and the spool
22
is allowed to rotate only by an angle corresponding to a twist of the torsion bar
23
. Therefore, the spool
22
is thereafter rotated under a tension increasing as the seatbelt is extracted. The locking mechanism described above is generally called as “a locking mechanism by a webbing sensor”.
The description above only illustrates an outline of the seatbelt retractor and there are complex mechanisms for use as a mechanism for stopping rotation of the lock gear
25
by the movement of the flywheel
30
and a mechanism for protruding the pawl
32
outside, for example. However, the seatbelt retractor is known and is used in common, so that more detailed description may be not necessary for those skilled in the art. Moreover, it is irrelevant to the principal part of the present invention, so that the more detailed description is omitted.
However, in the conventional seatbelt retractor, since the lock mechanism is operated after the seatbelt is actually extracted rapidly, a time lag for operating the lock mechanism may be developed. When the seatbelt is suddenly extracted during wearing the seatbelt, the lock mechanism may also be operated, so that uncomfortable feeling or unpleasantness may be given to an occupant.
The present invention has been made in view of such a situation, and it is an object of the present invention to provide a seatbelt retractor which can promptly operate a lock mechanism upon an emergency, and moreover, it is another object to provide a seatbelt retractor which does not provide uncomfortable feeling or unpleasantness to the occupant due to locking produced when the seatbelt is extracted for wearing the seatbelt.
SUMMARY OF THE INVENTION
First means for solving the problems described above is a seatbelt retractor comprising a mechanism for locking the rotation in the extracting direction of the seatbelt retractor upon receiving a collision predicting signal from a collision predicting device, the mechanism being independent of the rotational movement of a spool (first aspect of the invention).
The collision predicting device detects a vehicle acceleration, a distance to a front car, a vehicle velocity, hard braking by the driver, and so forth so as to predict an accident such as a collision prior to occurrence of the accident on the basis of the detected information, and the device is already known. In the first means, at the time when receiving a collision predicting signal from the collision predicting device, rotation of the seatbelt retractor in the extracting direction is locked. Therefore, differently from a conventional retractor, extraction of the seatbelt can be locked before the seatbelt is actually extracted, so that operation cannot lag behind.
In addition, in this case, the phrase “locking rotation in the extracting direction” means completely locking actual rotation including locking while allowing the rotation via the torsion bar mentioned in the description of the related art.
Also, if removing the extraction-locking mechanism by detecting extracting the seatbelt using the flywheel mentioned in the description of the related art, even when rapidly extracting the seatbelt during wearing the seatbelt, the seat belt is not locked and thereby eliminating uncomfortable feeling or unpleasantness from an occupant.
In the second means for solving the problems, according to the first means, the mechanism for locking the rotation in the extracting direction of the seatbelt retractor comprises a ratchet gear having saw-blade teeth for use in a ratchet mechanism at the external periphery and directly connected to a rotational shaft of the seatbelt retractor or engaged with a gear directly connected to the rotational shaft, a pawl arranged to be engageable with the saw-blade teeth, a lever for driving the pawl so as to engage with and disengage from the saw-blade teeth, a rotational body for driving the lever via a torque limiter, and a motor for driving the rotational body (second aspect of the invention).
In the second means, in a steady state, the rotational position of the motor is located at a position that the pawl is not engaged with saw-blade teeth of the ratchet gear. Upon receiving a collision predicting signal, the motor rotates, and the rotational body is thereby rotated. The lever is thereby driven so as to drive the pawl to a position engaging with the saw-blade teeth of the ratchet gear. Therefore, the pawl and the ratchet gear form a ratchet mechanism, so that the ratchet gear can rotate in the seatbelt-retraction direction while cannot rotate in the extracting direction. Accordingly, the rotational shaft of the seatbelt retractor directly connected to the ratchet gear or connected thereto via a gear is also prevented from rotating
Tanaka Koji
Tanji Hiromasa
Kanesaka & Takeuchi
Rivera William A.
Takata Corporation
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