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US 4,302,030 AGranted
Seat belt systems
AssigneeKangol Magnet Limited
InventorWilliam S. G. Clay
Life of this patent
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AssigneeKangol Magnet Limited
InventorWilliam S. G. Clay
Estimating the term…
A large road vehicle has a cabin subject to accelerations in normal driving conditions in excess of accelerations experienced by the vehicle as a whole and which are sufficient to lock the acceleration responsive retractor of the driver's seat belt system unnecessarily. To prevent such locking except under genuine emergency conditions, a solenoid in the retractor holds inoperative a locking mechanism responsive to retractor acceleration, until an inertia switch located on the vehicle chassis (and thus less exposed to acceleration than the cabin mounted retractor) senses a predetermined vehicle acceleration, when the switch de-energizes the solenoid to permit the retractor acceleration sensing mechanism to operate. The seat belt system is passive and a switch operated by the handle of the door adjacent the seat is open when the door is closed but closed when the door is opened so as to energize the solenoid and thereby prevent inadvertent locking during door opening movement.
In a vehicle including a chassis, a cabin, means mounting said cabin on said chassis to permit said cabin to experience accelerations in excess of those experienced by the chassis, and a seat and a seat belt system associated therewith mounted in said cabin, said seat belt system including a seat belt retractor adapted to lock against belt withdrawal in response to acceleration of the retractor beyond a first predetermined amount, the improvement comprising electrical anti-locking means in said retractor and having a first condition preventing locking thereof and a second condition permitting such locking, electrical acceleration sensing means adapted to change condition in response to an acceleration of said chassis exceeding a second predetermined amount, an electrical supply source, and circuit means connecting together said anti-locking means, said means and said supply source so that said anti-locking means is in said first condition thereof until said sensing means changes condition in response to said chassis acceleration.
In a vehicle including a chassis, a cabin capable of movement relative to the chassis, and a seat in the cabin, a seat belt system associated with said seat and comprising a seat belt, a retractor for said seat belt, locking means adapted to lock said retractor against belt withdrawal in response to a predetermined acceleration due to acceleration of said cabin, anti-locking means operative to prevent said retractor locking, and disabling means operatively connected to said chassis for rendering said anti-locking means inoperative in response to the sensing of a second predetermined acceleration of said chassis.
Dependencies are inferred from the claim text.