Chairs and seats – Body or occupant restraint or confinement – Safety belt or harness; e.g. – lap belt or shoulder harness
Reexamination Certificate
2000-03-10
2002-01-22
Nelson, Jr., Milton (Department: 3636)
Chairs and seats
Body or occupant restraint or confinement
Safety belt or harness; e.g., lap belt or shoulder harness
C297S480000
Reexamination Certificate
active
06340209
ABSTRACT:
TECHNICAL OF THE INVENTION
The present invention relates to a vehicle body acceleration sensor for use with a seat belt, and more particularly, to an improvement in a vehicle body acceleration sensor for use with a seat belt which is used for a seat belt retractor attached to a backrest of a reclining seat of a vehicle and which activates lock means for preventing withdrawal of a webbing in the event of an emergency.
BACKGROUND ART
For a seat belt apparatus for safely retaining a vehicle occupant on his seat, there has conventionally been used an emergency lock type retractor which has an emergency lock mechanism for physically locking a retractor through use of inertia sensing means for responding to urgent acceleration, collision, or deceleration and which safely and effectively restrains the occupant.
Inertia sensing means used for such an emergency lock type retractor includes a vehicle body acceleration sensor for sensing the acceleration of the vehicle body. For example, the vehicle body acceleration sensor is constructed such that, when an inertial body is moved as a result of collision or inclination of the vehicle body, a sensor arm provided on top of the inertial body is pivoted, thereby activating lock means for locking rotation in the direction in which the webbing is drawn-out from a take-up shaft around which a webbing is wound.
Recently, there have been proposed various types of vehicle body sensors for use with a seat belt, in which a retractor such as that mentioned previously is provided within a backrest of a reclining seat and which, even when the backrest is titled, can be activated in the same way as when the backrest is not reclined.
For example, like vehicle body acceleration sensors described in German Patent Publication No. 4,032,157, U.S. Pat. No. 4,978,087, and Japanese Patent Unexamined Publications No. Hei.1-202553 and No. Hei.3-148350, there have already been proposed various types of vehicle body acceleration sensors which are provided with transmission means, such as a flexible shaft or a gear device, for controlling the angle of a sensor case by pivotal movement of the sensor case about its pivot in synchronization with reclining action of a backrest, in such a way that an inertial body support surface formed on the sensor case is retained in an appropriate position with respect to the sensor case pivotally supported by a retractor base regardless of reclining angle of the backrest, or are provided with rotary drive means such as a servo motor which rotatively actuates the sensor case according to a reclining angle of the backrest.
By means of the seat belt apparatus having such a structure, even when the backrest is inclined or slid between the full forward and full back positions, the positional relationship between a shoulder belt of the webbing and a backrest remains unchanged, thereby ensuring superior restraining performance.
In a case where the sensor case is rotatively actuated by means of a servo motor, or the like, according to the reclining angle of the backrest, use of a motor adds to component costs, results in an increase in the number of components, and renders the structure of the seat belt apparatus complicated, thus leading to an increase in manufacturing costs.
In a case where the sensor case is rotated, through use of the transmission means, about its pivot in synchronization with the reclining action of the backrest according to the reclining angle of the backrest, the pivotable range of the sensor case is set so as to correspond to an optimum working range of the retractor which is attached to the backrest and is capable of appropriately restraining the occupant by means of webbing. However, the optimum working range of the retractor generally constitutes a portion of the reclining range of the backrest and is narrower than the reclining range. For this reason, in a case where the sensor case is rotatively actuated by means of transmission means—such as a flexible shaft or a gear device—interposed between the sensor case and seat hardware, when the backrest is reclined beyond the optimum working range of the retractor, the sensor case is actuated by way of the transmission means, thereby resulting in interference with another component or straining and damaging the sensor case.
To prevent such a problem, the angle at which the backrest is reclined is limited so as to match the pivotable range of the sensor case, with the result that the range of inclination of the backrest becomes narrower than that of a seat having not a built-in retractor, thereby rendering a vehicle seat very difficult to use.
In contrast, in a case where the sensor case is arranged so as to be able to pivot in synchronization with the reclining action of the backrest even when the backrest in reclined beyond the optimum working range of the seat belt, a large space is required for movement of the sensor case, thereby rendering the retractor large.
An angle sensing means provided in the transmission means for sensing the inclination of the backrest includes an angle sensing means for sensing the inclination of the backrest by sensing relative rotation between a member disposed in a seat and a member which is provided on the side of a recliner mechanism (a hinge mechanism of the seat) facing the backrest and which pivots together with the backrest.
Since the angle sensing means pivots in agreement with the pivotal movement of the backrest, the pivot of the angle sensing means is desirably placed in line with the reclining pivot of the backrest. As shown in
FIG. 78
, if a reclining pivot O of the backrest does not match a pivot Q of the angle sensing means, a pivotable angle &thgr; of the backrest does not match a pivotable angle &agr; of the angle sensing means at, e.g., a point V (a position where the angle sensing means is mounted on the backrest), thereby rendering impossible correct adjustment of the orientation of the sensor case.
In order to cause the reclining pivot of the backrest to coincide with the pivot of the angle sensing means, the reclining mechanism on which the angle sensing means is mounted and the angle sensing means must be manufactured with a high degree of dimensional precision. Both the reclining mechanism and the angle sensing means require a large number of components, thereby becoming expensive.
Accordingly, the object of the present invention is to provide a vehicle body acceleration sensor to be disposed in a retractor mounted on a backrest, and more particularly, to provided a vehicle body acceleration sensor for use with a seat belt which is capable of reliably and stably sensing the acceleration of a vehicle body regardless of the reclining angle of the backrest and which enables a reduction in manufacturing costs by employment of a simple mechanism.
DISCLOSURE OF THE INVENTION
The foregoing object of the present invention is achieved by a vehicle body acceleration sensor for use with a seat belt comprising:
a sensor case which is supported in a movable manner by a retractor base mounted on a backrest of a reclining vehicle seat;
a sensor arm which is pivotally mounted on the sensor case or the retractor base so as to move lock means between a first position where the lock means is actuated and a second position where the lock means becomes inoperative, the lock means preventing a take-up shaft, around which a webbing is wound, from rotating in a direction in which the webbing is drawn-out;
an inertial body which moves in relation to an inertial body support surface of the sensor case upon receipt of a velocity change of greater than a predetermined value, thereby moving the sensor arm to the first position; and
transmission means for moving the sensor case in synchronization with reclining action of the backrest according to a reclining angle of the backrest so that the inertial body support member is held at an appropriate orientation regardless of reclining angle of the backrest, wherein the lock means is actuated by means of movement of the inertial body caused when a predetermined acceleration acts on the vehicle b
Fukunaga Masanao
Hashimoto Yoshito
Yamamoto Kazuo
Jr. Milton Nelson
NSK Ltd.
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