[0001] The invention relates to a buckle latch for a seat belt, in particular a seat belt of a vehicle, such as a motor vehicle. Such buckle latches are inserted into a receptacle of a belt buckle in order to close the seat belt and are thus releasably locked to the belt buckle. In the event of an accident or a sharp braking operation of a vehicle equipped with the seat belt, the buckle latches have to absorb very high tensile forces. For this purpose, known buckle latches are composed of metal, for example a chrome-plated metal material. The buckle latch composed of metal generally has an opening which locks to the belt buckle and reliably absorbs forces occurring in the event of an accident or a sharp braking operation, and therefore the seat belt reliably restrains a passenger of the vehicle. In the case of known buckle latches, a portion having an opening for the belt strap is also surrounded by a plastics material. As a result, firstly, the fabric of the belt strap is protected, in particular when high forces occur. In addition, said plastics portion is intended to improve the appearance.

[0002] However, a disadvantage of known buckle latches is that, when the seat belt is not closed, the buckle latch composed of metal strikes in a rattling manner against components of the vehicle, for example of the B pillar, because of vibrations or shaking caused by the operation of the vehicle. The generation of noise is considerable and is perceived to be uncomfortable.

[0003] Starting from the explained prior art, the invention is therefore based on the object of providing a buckle latch of the type mentioned at the beginning which, while being highly operationally reliable, reduces rattling noises during operation.

[0004] The invention achieves the object by the subject of Claim 1. Advantageous refinements are found in the dependent claims, the description and the figures.

[0005] For a buckle latch of the type mentioned at the beginning, the invention achieves the object in that the buckle latch has a core made from a metal material, wherein the core is completely surrounded by a casing made from a plastic.

[0006] The buckle latch is part of a seat belt, preferably a seat belt of a vehicle, in particular a motor vehicle, such as an automobile. The seat belt can be provided in particular for a passenger vehicle or a truck. The buckle latch interacts with a belt buckle of the seat belt. In particular, the buckle latch can be received in a receptacle of the belt buckle and can thus be releasably locked to the belt buckle. The belt strap of the seat belt is guided through the buckle latch. For this purpose, the buckle latch generally has a first opening. Furthermore, the buckle latch generally has a second opening with which it locks to the belt buckle. For example, in the case of the three-point belts of automobiles, the belt strap is anchored at three points of the automobile. In the case of a driver's seat of a passenger vehicle, a first anchoring point is generally located in the lower region of the B pillar. An end fitting of the seat belt is generally provided here. A second anchoring point is formed by the belt buckle. The three-point belt is connected to the belt buckle by locking of the buckle latch thereto. This second anchoring point is generally located on the vehicle seat. The third anchoring point is formed by fastening the belt strap to the upper part of the B pillar.

[0007] According to the invention, the buckle latch has a core made from a metal material, which is completely surrounded by a casing made from a plastic. By means of the complete encasing of the metal core with plastic, rattling noises are considerably reduced since, for example when the seat belt is not closed, there is contact only still between the plastics encasing of the buckle latch and the B pillar covering which is generally formed from plastic. Such a plastic to plastic contact causes considerably smaller noises than contact between a metal material and plastic, as in the prior art. According to the invention, contact between components of the vehicle and the metal material of the core is therefore avoided. At the same time, because of the metal core of the buckle latch according to the invention, the high holding forces occurring, for example, in the event of an accident or a sharp braking operation of the vehicle continue always to be reliably absorbed.

Furthermore, the appearance of the buckle latch can be further optimized by selecting suitable plastics for the encasing. A reduction in weight is also possible by the volume of the metal core being reduced to the extent required for absorbing the retaining forces and the buckle latch otherwise being formed from plastic.

[0008] For particularly straightforward production, the casing can be injection-molded onto the core in a plastics injection molding process. However, it is also conceivable for the plastics casing to be composed of two different plastics, produced, for example, in a two- component injection molding process. An inner first portion of the plastics casing, which portion is attached directly to the metal core, can thus be composed of a harder plastic than an outer second portion which is attached to the first portion. Said second portion would then be in contact with the user of the vehicle and could be composed of a softer, haptically particularly pleasant plastic.

[0009] The core can be formed from a metal sheet. Production from a metal sheet is straightforward and permits a large configuration of the metal core. As a result, the high forces in the event of an accident or a sharp braking operation of the vehicle are

particularly reliably absorbed.

[0010] The geometry and the dimensions of the metal core can basically be adapted flexibly to the particular application, in particular to the forces to be anticipated during operation.

[0011] According to a further refinement, it is possible to form the core from a metal wire. As a result, a particularly flexible configuration of the metal core is possible. At the same time, a weight saving can thereby be achieved. The metal wire can have, for example, a round (circular) cross section. However, flat cross sections or the like would also be conceivable. The metal wire can in particular have two ends which lie opposite each other (in the produced state of the buckle latch). It is possible in principle for said ends not to be connected to each other. However, a connection of the ends can improve the stability of the buckle latch, in particular the capability of absorbing tensile forces acting on the buckle latch. For the connection, it can be provided, for example, that the ends of the metal wire are connected to each other in a form-fitting manner. There is therefore then a mechanical connection of the ends of the metal wire. Alternatively, it is also possible for the ends of the metal wire to be connected to each other in an integrally bonded manner, in particular welded. Both types of connection basically increase the capability of absorbing forces during operation.

[0012] The invention also relates to a seat belt, in particular a seat belt of a vehicle, comprising a buckle latch according to the invention and a belt buckle with a locking receptacle for the releasably locking reception of the buckle latch.

[0013] Exemplary embodiments of the invention are explained in more detail below with reference to figures, in which, schematically: [0014] FIG. 1 shows a buckle latch according to the invention for a seat belt in a sectional view according to a first exemplary embodiment,

[0015] FIG. 2 shows a buckle latch according to the invention for a seat belt in a sectional view according to a second exemplary embodiment, and

[0016] FIG. 3 shows a detail of the metal core of a buckle latch according to the invention for a seat belt according to a further exemplary embodiment.

[0017] Unless indicated otherwise, the same reference signs denote the same objects in the figures.

[0018] The buckle latch 10 as shown in FIG. 1 can be, for example, part of a seat belt of an automobile, for example a three-point belt. The buckle latch 10 has a core 12 made from a metal material, wherein the core is completely surrounded by a casing 14 made from a plastic. The core 12 is therefore surrounded on all sides by the plastics material of the casing 14. In the example shown in FIG. 1, the core 12 is formed from a metal sheet and has an elongate first opening 16 which is likewise surrounded by the plastic of the casing 14, and therefore the casing 14 forms an elongate first opening 18 which is correspondingly somewhat smaller than the first opening 16 of the core 12. A belt strap (not illustrated specially in the figures) of the seat belt is guided through said first opening 18 of the casing 14 during operation. The core 12 furthermore has a substantially rectangular second opening 20 which in turn is surrounded by the plastics material of the casing 14, and therefore the casing 14 forms a second opening 22 which is somewhat smaller than the second opening 20 of the core 12. In order to close the seat belt, that portion of the buckle latch 10 which has the second opening 22 of the casing 14 is inserted in a manner known per se into a corresponding belt buckle of the seat belt, with a releasable locking of the belt buckle to the second opening 22 of the buckle latch 10 occurring. A tensile force acting upward in FIG. 1 in the event of an accident or a sharp braking operation can thus be reliably absorbed by the core 12 made from metal, in particular the first opening 16 of the core 12, even if the plastic of the casing 14 fails.

[0019] In the example illustrated in FIG. 1, the casing 14 has been injection-molded onto the core 12 in a plastics injection molding process. [0020] FIG. 2 shows a buckle latch 10' according to a second exemplary embodiment. The buckle latch 10' shown in FIG. 2 has a core 12' which is formed from a metal wire and in turn is completely surrounded by a casing 14' made from plastic. The casing 14' in turn forms a first opening 18' for the passage of the belt strap and a second opening 22' for the releasable locking to the belt buckle of the seat belt. In the exemplary embodiment of figure 2, the metal wire of the core 12' forms a closed structure which surrounds the two openings 18' and 22' of the casing 14' . The ends of the metal wire forming the core 12' are connected to each other in an integrally bonded manner, in particular welded, in the exemplary embodiment of FIG. 2. Thus, even the core 12' of the buckle latch 10' according to FIG. 2, which core is formed from a metal wire, can reliably absorb a tensile force acting upward in the event of an accident or a sharp braking operation in figure 2, even if the plastic of the casing 14' fails.

[0021] From a comparison of figures 1 and 2, it can be seen that, in the case of the exemplary embodiment of FIG. 2, the surface formed by the core 12' made from metal wire and here in particular also the volume are smaller than in the case of the core 12 according to FIG. 1. In particular, in the exemplary embodiment of FIG. 2, the central region between the openings 18' and 22' is formed only by the plastic of the casing 14' while, in the case of the exemplary embodiment of FIG. 1, the core 12 fills this region with the first and second opening 16, 20 being formed. By means of the reduced volume of the metal core 12' in the case of the exemplary embodiment of FIG. 2, a reduction in weight is possible in comparison to the exemplary embodiment from FIG. 1.

[0022] In the case of the exemplary embodiment of FIG. 2, in turn, the plastics casing 14' has been injection-molded onto the metal core 12' in an injection molding process.

[0023] FIG. 3 illustrates part of a metal wire forming a metal core, as shown, for example, at the reference sign 12' in FIG. 2. In particular, FIG. 3 shows a mechanical connection of a first end 24 and a second end 26 of the metal wire. The connecting line between the ends 24, 26 is illustrated at the reference sign 28. As can be seen, the two ends 24, 26 are connected to each other in a form-fitting manner. [0024] The holding forces can be increased, even when the metal core is formed from a metal wire, both by the welded connection of the ends according to FIG. 2 and by the form- fitting mechanical connection of the ends according to FIG. 3.

List of reference signs

10 Buckle latch

10' Buckle latch

12 Core

12' Core

14 Casing

14' Casing

16 First opening

18 First opening

18' First opening

20 Second opening

22 Second opening

22' Second opening

24 First end

26 Second end

28 Connecting line