Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2000-10-26
2002-12-17
Jillions, John M. (Department: 3654)
Winding, tensioning, or guiding
Reeling device
With spring motor
C242S390800
Reexamination Certificate
active
06494395
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a seat belt retractor which is furnished inside a vehicle, such as an automobile.
A seat belt retractor which is equipped in an automobile, and the like, has a function of retracting a part of the seat belt pulled out too much when the passenger has taken a seat, pulled out the seat belt and coupled a tongue into the buckle. In order to realize this mechanism, in the seat belt retractor of the past, a single return spring has been used. When the person fastens the seat belt and releases one's hand after pulling out the seat belt in opposition to the force of this return spring and coupling the tongue to the buckle, the part of the seat belt pulled out too much is drawn into the seat belt retractor by the force of the return spring until it fits the body of the person.
In the seat belt retractor as explained above, it is necessary to simultaneously satisfy:
(1) that the seat belt pulled out too much is surely retracted until it fits the body of the person, and that when the person is not wearing it, the pulled out seat belt is surely housed in the housing part, and
(2) that unnecessary feeling of oppression is not provided to the chest, and the like, of the passenger when it is properly fastened.
However, with the seat belt retractor using the force of a single return spring, when a spring having weak force is used in order to lessen the feeling of oppression to the chest of the passenger when fastened, the retracting force during retraction or during housing of the belt becomes weaker, and the operability and storability are reduced. Conversely, when a spring having strong force is used in order to exhibit sufficient retracting force during retraction, there is a problem that the feeling of oppression to the chest of the passenger when properly fastened becomes greater.
Also, with the seat belt retractor of the past, because a single return spring is internally installed, there also is a problem that as the seat belt is pulled out further, the return spring is further wound and its force increases, and as the seat belt is pulled out further, the force to pull it out also increases.
As one means for solving such problems, there is an invention disclosed in Japanese Patent Publication (KOKAI) No. H3-552. This attempts to reduce the feeling of oppression of the passenger when properly fastened while assuring retracting force during retraction of the belt by using two springs as return springs, i.e. a main spring and an auxiliary spring. In detecting the coupling of the tongue and buckle of the seat belt with a detector, the forces of both the main spring and the auxiliary spring are transferred to the retraction mechanism in a state that the tongue and buckle are not coupled, and the force only of the main spring is transferred to the retraction mechanism when the tongue and buckle are coupled.
However, in this case as well, the problem that the force for pulling out the seat belt increases as it is pulled out further is not circumvented, and furthermore, a separate phenomenon has occurred such that when the seat belt is removed, as soon as the coupling of the tongue and the buckle is released, the retracting force suddenly becomes stronger, and it provides a feeling of discomfort to the passenger.
The present invention has been made in consideration of such circumstances, and it is an object of the invention to provide a seat belt retractor that surely retracts the seat belt by sufficiently great retracting force during retraction, and does not provide a feeling of oppression to the person when properly fastened, and moreover can eliminate the feeling of discomfort caused during retraction, and furthermore does not require great force when the person pulls out the seat belt.
SUMMARY OF THE INVENTION
In the first aspect for solving the aforementioned problems, a seat belt retractor includes a spring member that generates retracting force weak enough not to provide a feeling of oppression to a passenger when the passenger has fastened the seat belt, and a motor that is driven only in the direction of retracting the seat belt and generates retracting force stronger than the spring member.
In this respect, it can be made such that the retracting force is provided by the spring member when the seat belt is properly fastened, and made such that the retracting force having added retracting force by a motor to this or retracting force of the motor alone is provided to the seat belt when retracting the seat belt in a state when the tongue and the buckle are not coupled. Therefore, the seat belt can be fitted to the person with a retracting force that does not provide a feeling of oppression to the person when properly fastened, and it can be retracted with great retracting force during retraction. Also, because great retracting force is generated by the motor, even when great retracting force is suddenly applied when the coupling of the tongue and the buckle is released, there is no situation such as the tongue striking the window. As for judgment of whether it is properly fastened or retracted, it is assumed such that, in the same manner as in the past, it is considered to be a retraction time for a specified time after the coupling of the tongue and the buckle is released, and it is considered to be properly fastened in other cases including pulling out of the seat belt.
In the second aspect for solving the aforementioned problems, the motor is provided with driving force only when the tongue and buckle attached to the seat belt are not coupled.
In this second aspect, when the tongue and the buckle are coupled, it is considered that the person has finished fastening of the seat belt, and driving of the motor is not performed. Therefore, because absorption of the slack of the seat belt and fitting to the person is performed by only the force of the spring member, at this extent, a feeling of oppression is not provided to the person.
In the third aspect for solving the aforementioned problems, the motor is not provided with driving force when the seat belt is withdrawn.
In the third aspect, even if the tongue and the buckle are not coupled, when the seat belt is withdrawn in the direction of pulling out by a person, driving of the motor is stopped. Therefore, because there is no need to pull out against the driving force of the motor when the person pulls out the seat belt, it can be pulled out easily. Determination of whether or not the seat belt is driven in the direction of being pulled out can be performed, for example as shown in the example to be described later, by a switch that detects the direction of rotation of the drive shaft of the seat belt driving mechanism.
In the fourth aspect for solving the aforementioned problems, retraction by the motor is performed for only a specified time or a specified number of revolutions after coupling of the tongue and buckle is detected.
In the fourth aspect, substantially all of the slack can be absorbed rapidly by performing retraction by the motor for only a specified time or a specified number of revolutions after the seat belt is fastened, and coupling of the tongue and the buckle is detected. After that, because retraction by the spring member is performed rather than retraction by the motor, a feeling of oppression is not provided to the person.
In the fifth aspect for solving the aforementioned problems, in any of the first to fourth aspects, it is equipped with a detector that detects a direction of rotation of a spool that winds up the seat belt.
In the fifth aspect, for example when the seat belt is pulled out manually, control such as detecting that rotation and stopping the rotation of the motor can be performed.
In the sixth aspect for solving the aforementioned problems, it has a power propagation mechanism that propagates retracting force of the spring member and the motor to the seat belt, and the power propagation mechanism has a clutch mechanism that disengages the mechanical power propagation circuit between the motor and the seat
Fujii Hiroaki
Tanji Hiromasa
Jillions John M.
Kanesaka & Takeuchi
Takata Corporation
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