Chairs and seats – Crash seat
Reexamination Certificate
2000-01-21
2001-07-03
Brown, Peter R. (Department: 3636)
Chairs and seats
Crash seat
C297S216130
Reexamination Certificate
active
06254181
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to vehicle seats having movable safety bars designed to improve the safety of the occupant of the seat in the event of an accident.
More specifically, the invention relates to a vehicle seat comprising:
a backrest,
a seat extending in a longitudinal direction between a front end and a rear end adjacent to the backrest,
a safety bar extending horizontally, perpendicular to the longitudinal direction, inside a seating element selected from the seat and the backrest, this seating element having a support surface designed to support an occupant, the safety bar being designed to restrict displacement of the occupant in a certain direction of displacement in the event of an accident, said safety bar being arranged, under normal circumstances, in a set-back position relative to the seating element, which is spaced back from the support surface, relatively speaking,
connecting means for connecting the safety bar to the seating element,
at least one activating device which can be triggered in the event of an accident in order to displace the safety bar relative to the seating element from its set-back position into an activated position closer to the support surface of the seating element, the connecting means being designed so that the safety bar follows a predetermined activation trajectory relative to the seating element until it reaches said activated position,
and energy-dissipating means designed to decelerate the safety bar as it is displaced from its activated position to an end-of-travel position, during which it follows a certain dissipation trajectory directed substantially in the direction in which the occupant is displaced in the event of an accident.
BACKGROUND OF THE INVENTION
Safety bars of this type are known in the form of what are referred to as “anti-submarining” bars, their purpose being to prevent the occupant of the seat from sliding underneath the ventral strap of his safety belt and being forced into the upholstery of the seat if the vehicle is subjected to a frontal impact.
Document FR-A-2 747 080 describes an example of a seat in which a safety bar of this type is pivotally mounted on connecting plates and is moved upwards and forwards under the action of a pyrotechnic pre-tensioning device if the vehicle is subjected to a frontal impact. These features prevent the safety bar from impinging on the comfort of the occupant under normal circumstances, yet make it effective when moved into the activated position in the event of an accident.
The disadvantage of this known seat is that when the safety bar is in the set-back position it is located towards the rear of the seat, relatively speaking, at a point where the seat upholstery and the elastic metal layer supporting this upholstery are susceptible to local deformation under the weight of the occupant and may impair or even prevent correct displacement of the safety bar into its activated position in the event of an accident.
This being the case, the safety bar remains locked in a rear position and is unable to fulfil its function which means that the pelvis of the occupant is at risk of digging in as it moves forward underneath the ventral strap of the safety belt when subjected to impact, which can cause serious injury to the occupant.
OBJECTS AND SUMMARY OF THE INVENTION
The specific objective of the invention is to overcome this drawback.
To this end, the invention proposes a seat of the type in question which is essentially characterised in that the connecting means are designed so that the activation trajectory followed by the safety bar relative to the seating element comprises at least one portion common to the dissipation trajectory, this portion of the activation trajectory commencing at an intermediate point on the dissipation trajectory and continuing as far as the activated position.
As a result of these features, even if the final displacement of the safety bar to its activated position is hampered, in particular due to poor positioning of the occupant on the seat, the final position of the safety bar after the activating device has been triggered is always on the dissipation trajectory between the above-mentioned intermediate position and the activated position so that the safety bar can then follow said dissipation trajectory as far as the end-of-travel position, gradually decelerating the occupant as kinetic energy is dissipated.
The safety bar is therefore able to fulfil its role effectively under any circumstances.
Preferred embodiments of the invention offer the option of using in addition one and/or the other of the following features:
connecting means comprising:
a support device which can be displaced relative to the seating element between a rest position on the one hand, in which the safety bar is spaced back from its activated position relatively speaking, and an activation position on the other, in which said safety bar is closer to its activated position,
and locking means for immobilising the support device of the safety bar relative to the seating element when this support device reaches its activation position, the safety bar being movable, relative to this support device, between first and second stop positions corresponding respectively to the activated and end-of-travel positions of the safety bar when the support device is in its activation position, said safety bar being in an initial position part-way between said stop positions under normal circumstances, the support device, the activating device and the energy-dissipating means being designed so that when the activating device is triggered:
the support device is initially displaced from its rest position to its activation position without the safety bar being essentially displaced relative to the support device,
after which said safety bar is displaced relative to the support device into its first stop position, corresponding to its activated position,
and the safety bar is finally displaced relative to the support device from its first stop position to its second stop position, which corresponds to the end-of-travel position;
the activating device is designed to act on the safety bar so as to displace said safety bar to its activated position and to retain the safety bar in said activated position until a predetermined force is applied to said bar to shift it to its end-of-travel position, said predetermined force being less than a force applied to the safety bar by the activating device in order to displace it into its activated position;
the energy-dissipating means comprise a mechanical linking device which links the seating element to at least a part of the activating device, this mechanical linking device being designed to allow the safety bar to be displaced relative to its support device into its end-of-travel position when the safety bar is subjected to a force directed towards said end-of-travel position and at least equal to said predetermined force;
the activating device comprises a pyrotechnical actuator which drives a cable attached to the safety bar, which cable is linked to the seating element by said mechanical linking device;
changing direction, the cable passes over at least one return guide between the pyrotechnical actuator and the safety bar, the mechanical linking device comprising the return guide on the one hand and a linking element on the other which links the return guide to the seating element;
said linking element is a slot which is provided in a rigid element belonging to the seating element and which surrounds a rigid member joined to the return guide, the edges of this slot being sufficiently close together to prevent any displacement of the return guide relative to the seat under normal circumstances, and the edges of the slot being designed to move apart by plastic deformation to allow the return guide to be displaced forwards when the safety bar is subjected to a force directed towards the end-of-travel position and at least equal to said predetermined force;
said linking element has a plastically stretchable metal plate;
the support
Aufrere Christophe
Levernieux Erik
Morin Gerald
Bertrand Faure Equipements SA
Brown Peter R.
Marshall O'Toole Gerstein Murray & Borun
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