Land vehicles – Wheeled – Running gear
Reexamination Certificate
1999-05-19
2001-01-09
English, Peter C. (Department: 3619)
Land vehicles
Wheeled
Running gear
C180S268000, C074S492000
Reexamination Certificate
active
06170874
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device for protection of occupants in a vehicle. More particularly, the present invention relates to such devices which are intended to be used in energy absorbing steering systems for motor vehicles. The invention also relates to a method for occupant protection in vehicles.
BACKGROUND OF THE INVENTION
In motor vehicles, it is a general goal to reduce the effects of a collision on the occupants of the vehicle as much as possible. In today's cars, three-point seatbelts are therefore normally employed to restrain the occupants of the vehicle. In a known manner, the seatbelts offer good protection and increased safety for the occupants should a collision take place.
Nowadays, there is also a desire to provide steering systems in vehicles which are energy-absorbing. The reason for this desire, which is dictated by legislation in certain countries, is that there is a need to offer some degree of protection to a driver who is not wearing a seatbelt when he is thrown towards the steering wheel in a collision.
It is previously known to design the steering system of the vehicle so that it absorbs energy when the driver of the car is thrown forwards and impacts the steering wheel during a collision. This can be achieved, for example, by designing the steering wheel with deformable and flexible spokes. This can also be achieved by arranging the steering shaft of the vehicle in a particularly designed energy absorbing steering column which is attached to the stress-bearing structure of the vehicle. In the event of a collision, when the steering wheel, and thus also the steering column, are influenced by a very large force as a result of the occupant being thrown forwards, this force will be transmitted from the steering wheel to the steering column. In this manner, the steering column will be displaced a certain distance relative to the vehicle structure. During this displacement, energy will be absorbed which, as a consequence, reduces the effects on the driver during the collision sequence.
Apparatus is disclosed in U.S. Pat. No. 4,978,138 for energy absorption in a steering system for vehicles. This apparatus is based on the principle that if the driver is not wearing his seatbelt, the steering system will absorb energy when the driver is thrown against the steering wheel during a possible collision. To achieve this, the arrangement includes a particular deformable and energy-absorbing bracket which is connected to the steering column. In order to determine whether the driver is wearing his seatbelt, a sensor is arranged on the seatbelt lock. This known arrangement also includes means for protecting the driver's knees, which means is activated irrespective of whether the driver is wearing his seatbelt or not. If the driver is wearing his seatbelt, the force from the knees will be absorbed by the knee protector as the steering wheel is displaced, whereby it is possible to prevent the upper body and head of the driver from impacting the steering wheel. The arrangement according to this patent, however, suffers from the disadvantage that the circumstances in which the driver can in fact impact the steering wheel during a collision even if he is wearing his seatbelt are not taken into account. This can occur, for example, when the driver has his seat in a well forward position or when the seatbelt is unusually slack.
SUMMARY OF THE INVENTION
In accordance with the present invention, these and other objects have now been realized by the invention of apparatus for protecting the occupant of a motor vehicle including a seatbelt for restraining the occupant and a stress-bearing structure, the apparatus comprising a steering shaft, a steering column supporting the steering shaft, the steering column displaceably mounted with respect to the stress-bearing structure, a first energy-absorbing unit for absorbing energy upon displacement of the steering column with respect to the stress-bearing structure by the occupant, a sensor for detecting a condition in which the occupant is restrained by the seatbelt, a second energy-absorbing unit for absorbing energy upon displacement of the steering column with respect to the stress-bearing structure by the occupant, and a locking member for permitting the absorption of energy by the second energy-absorbing unit by displacement of the steering column with respect to the stress-bearing structure by the occupant when the condition is detected by the sensor.
In accordance with one embodiment of the apparatus of the present invention, the locking member prevents absorption of energy by the second energy-absorbing unit by displacement of the steering column with respect to the stress-bearing structure by the occupant when the condition is not detected by the sensor.
In accordance with one embodiment of the apparatus of the present invention, the energy capable of being absorbed by the first energy-absorbing unit is less than the energy capable of being absorbed by the second energy-absorbing unit.
In accordance with another embodiment of the apparatus of the present invention, the second energy-absorbing unit comprises a first carriage fixedly mounted with respect to the steering column, a second carriage fixedly mounted with respect to the stress-bearing structure, the first and second carriages being displaceably mounted with respect to each other, and a second energy-absorbing element for absorption of the energy upon displacement of the first carriage with respect to the second carriage. In a preferred embodiment, the locking member comprises an electrically operated solenoid. Preferably, the electrically operated solenoid is mounted on one of the first and second carriages, the electrically operated solenoid including a piston, and wherein the other of the first and second carriages includes a recess cooperating with the piston. In accordance with a preferred embodiment, the electrically operated solenoid is mounted on the second carriage and the other of the first and second carriages comprises the first carriage.
In accordance with another embodiment of the apparatus of the present invention, the second energy-absorbing element comprises a strip including a first end and a second end, the first end of the strip being affixed to the first carriage and the second end of the strip being affixed to the second carriage.
In accordance with the present invention, these objects have also been overcome by the invention of a method for protecting the occupant of a motor vehicle including a seatbelt for restraining the occupant, a stress-bearing structure, a steering shaft, and a steering column supporting the steering shaft, the steering column being displaceably mounted with respect to the stress-bearing structure, the method comprising detecting a condition in which the occupant is restrained by the seatbelt, absorbing energy through a first energy-absorbing unit upon displacement of the steering column with respect to the stress-bearing structure by the occupant, and absorbing energy through a second energy-absorbing unit upon displacement of the steering column with respect to the stress-bearing structure when the condition is detected. In accordance with one embodiment, the method includes preventing absorption of the energy by the second energy-absorbing unit by displacement of the steering column with respect to the stress-bearing structure by the occupant when the condition is not detected.
In accordance with one embodiment of the method of the present invention, the energy capable of being absorbed by the first energy-absorbing unit is less than the energy capable of being absorbed by the second energy-absorbing unit. Preferably, the second energy-absorbing unit includes a locking member having a first actuated condition for preventing the absorption of energy by the second energy-absorbing unit, and a second non-actuated condition for permitting the absorption of energy by the second energy-absorbing unit, whereby the locking member is actuated when the condition is detected, the method
AB Volvo
English Peter C.
Royston, Rayzor, Vickery, Novak & Druce, L.L.P.
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