Chairs and seats – Body or occupant restraint or confinement – Safety belt or harness; e.g. – lap belt or shoulder harness
Reexamination Certificate
1999-10-18
2001-10-16
Nelson, Jr., Milton (Department: 3624)
Chairs and seats
Body or occupant restraint or confinement
Safety belt or harness; e.g., lap belt or shoulder harness
C297S480000
Reexamination Certificate
active
06302489
ABSTRACT:
DESCRIPTION
The present invention relates to a retractor for a vehicle safety restraint seat belt and particularly to a retractor for use in the rear passenger seats of a vehicle and to a safety locking arrangement therefor.
Retractors for rear seat belts are often mounted on the seat back rest itself since space is at a premium in the rear passenger compartment. For the seat belt to be effective therefore the back rest must be fastened securely to a fixed part of the vehicle. Normally this would be the case. However in some vehicles, such-as so-called station-wagons or estate cars and so-called hatchback cars, the rear seat back rest can be unlatched from its fastened upright position and rotated into a horizontal position to increase the luggage capacity of the vehicle. in some models the back rest is split and one part may remain upright to accommodate a seated passenger while the other part is lowered to allow bulky luggage to overflow from the luggage compartment behind the seat back.
In both cases there is a danger that when the seat back rest is returned to the upright position it may not be securely locked. In a crash, the rear passenger will then not be safely restrained because the retractor, attached to the seat back, will move when the seat back moves under the inertial loading caused by the crash.
The rear seat retractor is constructed in a similar manner to a front seat retractor and has both a web sensor and a vehicle sensor. The web sensor locks the retractor against pay-out i, the belt webbing is suddenly jerked, as would happen if it were suddenly loaded by the inertia of the user in a crash. This is known technology. The vehicle sensor detects a sudden change of speed of the vehicle and locks the retractor, again in a manner known to those skilled in the art.
The vehicle sensor typically comprises an inertia sensitive ball resting freely in a cup. A sudden deceleration of the vehicle causes the ball to keep moving and to ride up the side of the cup. A pawl resting on the ball is thus deflected upwards and this pawl activates a locking mechanism to lock the retractor spool against rotation and thus against further pay-out of webbing. The geometry of the ball type vehicle sensor means that it will also be activated if the retractor is tilted. This is used in DE 29 27 159 and GB 2 249 339 as an inherent seat back tilt sensor. If the seat back is not upright then the vehicle sensor locks the retractor against pay-out and it cannot be used.
However this known arrangement will not detect a rear seat back which is in the upright position but is not locked securely into the upright position. In this situation the retractor of the known arrangement can be used to fasten a vehicle occupant who will be unaware that the retractor is free to move and thus that he is not safely restrained.
In GB 2 286 624 a sensor is located in the seat back latch itself. When this detects that the latch is securely fastened it releases an additional locking device on the retractor to allow the retractor to be used. This is an expensive system requiring an additional locking device to be fitted to the retractor.
The present invention aims to provide an improved safety locking arrangement for a retractor in a rear seat.
According to the present invention there is provided a retractor for a vehicle safety restraint for use in a rear vehicle seat, the retractor comprising:
seat belt webbing wound on a rotatable spool, and a vehicle sensor having
an inertial sensor mass supported in a housing and movable relative thereto when vehicle acceleration or deceleration exceeds a predetermined magnitude,
a vehicle sensor pawl arranged to be moved, in response to movement of the mass, from a position in which the spool is freely rotatable into a spool locking position,
a seat back latching condition detector, adapted to be located in a latch for the rear seat back,
means connecting the latching condition detector to the vehicle sensing pawl, the connecting means being operable to move the pawl into the spool locking position when a seat back de-latched condition is detected.
According to a preferred embodiment of the present invention the connecting means comprises a bowden cable which is moved, preferably pulled, when the latch is in a disengaged state. The bowden cable is connected to a piston in the retractor which is spring biased to a position in which it has no effect on the retractor. However when the seat back latch is disengaged, the bowden cable pulls the piston against the spring bias The piston operates a lever which rotates the vehicle sensor pawl into the spool locking position in which the spool is locked against belt webbing pay-out. Thus the retractor cannot be used by an occupant who is thus alerted to the insecure state of the seat back.
Once the seat back latch is properly engaged, the pull on the bowden cable is released and the piston in the retractor returns to the normal position. The retractor is free to pay-out, subject to inertial influence on the vehicle sensor—such as in a crash
A retractor according to the invention is advantageous compared to known such retractors. Since the vehicle sensor pawl is used for locking the spool against belt webbing payout, a minimum number of extra components is reouired with attendant cost savings and increased reliability. In addition, in the safety locking condition, the retractor is fully and positively locked in a load bearing manner. The additional retractor locking devices used in known systems comprise much weaker, simple pawl engagement systems which are less reliable and are not capable of withstanding high loads.
REFERENCES:
patent: 4610480 (1986-09-01), Yamada et al.
patent: 5495994 (1996-03-01), Rumpf et al.
Congress Financial Corporation (Florida)
Jr. Milton Nelson
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