Chairs and seats – Body or occupant restraint or confinement – Safety belt or harness; e.g. – lap belt or shoulder harness
Reexamination Certificate
1999-09-17
2001-07-03
Cuomo, Peter M. (Department: 3636)
Chairs and seats
Body or occupant restraint or confinement
Safety belt or harness; e.g., lap belt or shoulder harness
C242S384400
Reexamination Certificate
active
06254191
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a seatbelt retractor to be mounted in a backrest. More specifically, this invention is concerned with a seatbelt retractor in which the spatial orientation of a sensing member responsible to a sudden acceleration, collision or deceleration is suitably adjustable depending on the angle of reclining of the backrest.
2. Description of the Related Art
As retractors for seatbelt systems each of which is used to safely hold a vehicle occupant or the like in a seat, emergency locking retractors have been used conventionally. To assure effective and safe restraint of an occupant, an emergency locking retractor is provided with an emergency locking mechanism to physically lock it by a sensing member which responds to a sudden acceleration, collision or deceleration.
Sensing members employed in these emergency locking retractors include those capable of sensing accelerations or tiltings of vehicle bodies. Such sensing members are each constructed in such a way that, when an inertia member is caused to move as a result of a collision of a vehicle body, for example, a sensor arm arranged on an upper part of the inertia member is caused to swing and a locking mechanism for locking rotation of a takeup spindle, on which a webbing is wound, in a webbing-releasing direction is then actuated.
In recent years, proposals have been made about seatbelt systems of the type that a retractor such as that mentioned above is mounted in a backrest of a reclining seat for a vehicle or the like and is operable similarly even when an angle of reclining of the backrest is changed.
For example, a seatbelt system disclosed in German Utility Model No. 8503541 makes it possible to maintain the spatial orientation of a sensing member in a suitable orientation irrespective of the angle of reclining of a backrest by causing a wire to move in accordance with a reclining operation of the backrest such that a sensor case is caused to pivot by the wire.
The above-described sensor case of the seatbelt system, however, undergoes swinging about a shaft which is located adjacent a position where a sensor arm and a ratchet wheel engage, so that the manner of contact (angle of contact) between a free end of the sensor arm and the ratchet wheel changes when the backrest is reclined and the spatial orientation of the sensing member varies. This change in the manner of contact involves a potential problem in that the sensor arm may fail to stop the ratchet wheel at a predetermined position and hence to allow a locking mechanism to function properly.
In a retractor making use of ratchet wheel, there is a correlation between the position of a sensor arm of a sensing member and a position where a locking mechanism is actuated, and a predetermined phase has been set. Moreover, there is a limitation to the position of the sensing member, where the locking mechanism can be properly actuated, and accordingly, it is improper to arrange the sensing member at a position other than the above-mentioned position. In a locking mechanism of the type that a rotation preventing member arranged on a takeup spindle is brought into engagement with an engaged tooth arranged on a retractor base when a ratchet wheel arranged on the takeup spindle is stopped from rotation and relative rotation takes place between the ratchet wheel and the takeup spindle, the timing of actuation of the locking mechanism varies unless the engaged tooth of the retractor base, said engaged tooth serving to set a locking position, and the engaged teeth of the ratchet wheel is constant in phase. In a construction of the type that locking is achieved by an engagement of a rotation preventing member with one of engaged teeth continuously arranged on a retractor base, a variation in the timing of actuation of the rotation preventing member may lead to such a situation that the rotation preventing member fails to reach a position where the rotation preventing member is supposed to engage one of the engaged teeth, thereby resulting in an insufficient engagement. Forced rotation of the takeup spindle to make this engagement sufficient is however not preferred because unduly large force acts, for example, on a sensor arm or the like. If the timing of actuation of the rotation preventing member varies and the position of the rotation preventing member and that of the engaged teeth of the retractor base become too close to each other, on the other hand, the rotation preventing member and the engaged teeth of the retractor base may hit each other at their edges, thereby possibly resulting in damages to the engaged teeth.
SUMMARY OF THE INVENTION
With the foregoing circumstances in view, the present invention has as an object the provision of a seatbelt retractor having high reliability in that, even when a backrest is in different reclined positions, accelerations of a vehicle body can be always sensed without failure to assure proper actuation of a locking mechanism.
The above-described object of the present invention can be achieved by a seatbelt retractor comprising:
a retractor base to be mounted on a backrest;
a takeup spindle rotatably supported on the retractor base;
a locking mechanism for connecting the takeup spindle and the retractor base with each other via a pawl such that rotation of the takeup spindle in a webbing-releasing direction is locked;
a sensing member for actuating the locking mechanism by sensing a predetermined acceleration or tilting, said sensing member being supported about the takeup spindle such that the sensing member is pivotal depending on an angle of reclining of the backrest; and
a buffer mechanism incorporated in the locking mechanism such that, after the sensing member has acted on a portion of the locking mechanism, the portion is allowed to rotate relative to the takeup spindle until the takeup spindle and the retractor base are connected with each other via the pawl.
The above-described object of the present invention can also be achieved by a seatbelt retractor comprising:
a retractor base to be mounted on a backrest;
a takeup spindle rotatably supported on the retractor base;
a locking mechanism for connecting the takeup spindle and the retractor base with each other via a pawl such that rotation of the takeup spindle in a webbing-releasing direction is locked;
a sensing member for actuating the locking mechanism by sensing a predetermined acceleration or tilting, said sensing member being supported about the takeup spindle such that the sensing member is pivotal depending on an angle of reclining of the backrest; and
a locking adjusting mechanism incorporated in the locking mechanism such that the takeup spindle and the retractor base can be connected in a predetermined relationship via the pawl irrespective of a position of the sensing member relative to the retractor base.
The above-described object of the present invention can also be achieved by a seatbelt retractor comprising:
a retractor base to be mounted on a backrest;
a takeup spindle rotatably supported on the retractor base;
a pawl supported on one of the takeup spindle and the retractor base;
plural engaged portions with which the pawl is engageable, said plural engaged portions being arranged on the other one of the takeup spindle and the retractor base;
a sensing member for sensing a predetermined acceleration or tilting,
an adjusting mechanism for causing the sensing member to move relative to the retractor base depending on an angle of reclining of the backrest such that the spatial orientation of the sensing member is adjusted into a suitable orientation;
a transmission mechanism for transmitting rotation of the takeup spindle to the pawl upon actuation of the sensing member such that the pawl is brought into engagement with the engaged portions;
a ratchet wheel connected with the transmission mechanism and having engaged portions with which the sensing member can be brought into engagement upon actuation of the sensing member; and
a buffer mechanism arranged between the engaged portions of t
Hashimoto Yoshito
Yamamoto Kazuo
Crowell & Moring , L.L.P.
Cuomo Peter M.
NSK Ltd.
Vu Stephen
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