Belt locking device for a vehicle seat

In a belt locking device for a vehicle seat, in particular a motor vehicle seat, having a moveably attached belt lock (19), a tightening unit (13) supported on a structure-fixed support element (29), and a transmission element (21) acting between the tightening unit (13) and the belt lock (19), wherein, in the event of a crash, the tightening until (13) pulls the belt lock (19) from an initial position into a crash position by way of the transmission element (21), the position of the tightening unit (13) can be changed in a longitudinal direction of the transmission element (21) relative to the support element (29).

BACKGROUND OF THE INVENTION

The present invention relates to a belt locking device for a vehicle seat, in particular a motor vehicle seat, with the belt locking device having a moveably attached belt lock, a tightening unit supported on a structure-fixed support element, and a transmission means acting between the tightening unit and the belt lock, wherein, in the event of a crash, the tightening unit pulls the belt lock from an initial position into a crash position by means of the transmission means.

In a belt locking device of the type discussed immediately above, when there is a wide middle console between the vehicle seats, there exists the problem that a belt lock that is in a low position for optimum belt run can be poorly accessible.

BRIEF SUMMARY OF SOME ASPECTS OF THE INVENTION

An aspect of the present invention is the provision of improvements to a belt locking device of the type mentioned above. In accordance with one aspect of the present invention, a belt locking device for a vehicle seat, in particular a motor vehicle seat, has a moveably attached belt lock, a tightening unit supported on a structure-fixed support element, and a transmission means acting between the tightening unit and the belt lock, wherein, in the event of a crash, the tightening unit pulls the belt lock from an initial position into a crash position by means of the transmission means, and wherein the position of the tightening unit can be changed in a longitudinal direction of the transmission means relative to the support element.

By providing means to change the position of the tightening unit relative to the support element in the longitudinal direction of the transmission means, it is possible to provide, in addition to the belt tightening function, a comfort position that is more extended in comparison with the initial position of the belt lock, and in which the belt lock is more easily accessible. Once the passenger has put on the seatbelt, the belt lock returns to its initial position. By changing the position of the tightening unit, the belt lock is moved by means of the transmission means, i.e. the belt lock, tightening unit and support element are in series with respect to the force load occurring during tightening and when the belt is under functional load, i.e. a serial solution has been realized for both situations in which the belt is tightened (comfort and crash). As a rule, the transmission means is tension and pressure proof and flexible, with the option of a spring or another energy storage means keeping the belt lock in an upright position.

The position of the tightening unit can preferably be changed by means of a motor, i.e. the tightening unit is driven by a motor, on the one hand, in order to define a specific movement and, on the other hand, to increase comfort. To protect the support element of the tightening unit from dirt and damage, it is preferably located in a structure-fixed casing which also houses the motor and in which the belt lock is supported for example through a deflector and the spring. Fixing the casing to the structure can be realized with e.g. the seat frame, the upper rail, the lower rails or the vehicle structure.

In a preferred embodiment, the support element is in the form of a motor-driven rotatable spindle nut supported inside the casing, into which is screwed a spindle, the rotation of the motor being translated into a shifting of the tightening unit with simultaneous gear reduction. The spindle can be part of the tightening unit, i.e. of the tightening casing or, optionally, can be an independent element bearing against the tightening casing or being attached to it. In order to save construction space, the transmission means is preferably led through the spindle, which would then have to be hollow (e.g., define a passageway).

The invention is applicable to all vehicle seats having a belt tightener. Depending on the control and available sensors, different situations such as, for example, sitting down, opening the door, turning off the engine, or crash, may cause the comfort position to be assumed.

Other aspects and advantages of the present invention will become apparent from the following.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

A belt locking device1for a vehicle seat3of a motor vehicle is fixed to the structure of the vehicle seat3on the side of the seat3that is adjacent to the vehicle's center tunnel. The purpose of the belt locking device1is to releasably attach a safety belt5of the vehicle seat3. The arrangement of the vehicle seat3within the vehicle and the vehicle's normal direction of travel define the following directional indications. The belt locking device1has an oblong casing11whose longitudinal direction aligns with the direction of travel, and a pyrotechnical tightening unit13that is moveable in the direction of travel, is partly arranged inside the casing11, and is otherwise protruding frontward. The belt locking device1furthermore has a deflector15arranged at the rear end of the casing11, a spring17in the form of a helical spring pointing obliquely away from the deflector15frontward, and a belt lock19arranged at the upper end of the spring17for receiving the belt tongue of the safety belt5.

A traction and pressure proof, flexible transmission means21, in the present case a steel cable, is run from the tightening unit13backward and obliquely upward via the deflector and through the spring17towards the belt lock19, and is attached to the belt lock19. The transmission means21thus acts between the tightening unit13and the belt lock19. The transmission means21is attached so that it can move in the longitudinal direction of the transmission means21relative to the casing11, and flexibly transversally to the casing11. The spring17is enclosed in bellows23that extends between the belt lock19and the deflector15. The bellows23provides protection from dirt and other external effects. A motor25is supported in the casing11. The motor25is in gear connection with a spindle nut29by means of a spur gear27. The spindle nut29is screwed onto a non-rotating, hollow spindle31forming a rear part of the tightening unit13and through which the transmission means21is running towards the rear. The spindle nut29, which is rotatably supported in the casing11, acts as a support element for the tightening unit13. In the initial position, the rear end of the spindle31is located at least approximately within the spindle nut29.

In the event of a crash, the belt locking device1executes the known belt tightening function, i.e. the tightening unit13ignites and a part thereof rushes forward—supported on the part that is connected to the spindle31and pulling the belt lock19downward by means of the transmission means21, against the force of the spring17. This crash position is shown inFIG. 4. The safety belt5being locked in the belt lock19is tightened, i.e. a possible looseness in the belt is removed, so that the passenger is moved forward as little as possible.

The belt locking device1also has a comfort function because of a change in the position of the tightening unit13. When a passenger sits down on the vehicle seat3, this event being registered by the seat occupation recognition sensors, the motor25is activated, pushing the spindle31backward by means of the spindle nut29. The tightening unit13that is carried along also moves the transmission means21backward, so that the spring17can use the freed path to extend the belt lock19, as is shown inFIG. 3. The belt lock19thus becomes more easily accessible for the passenger. As soon as the safety belt5is completely buckled, the motor25moves the spindle31forward, i.e. it again pulls in the belt lock19, until the optimal belt run is achieved and the looseness of the belt has been removed.

In a “postsafe”-able variation, after the crash the belt lock19is also brought into the comfort position by means of the motor25, if this is still possible, in order to give rescuers easier access to the passenger.

It will be understood by those skilled in the art that while the present invention has been discussed above with reference to an exemplary embodiment, various additions, modifications and changes can be made thereto without departing from the spirit and scope of the invention as set forth in the following claims.