Seat belt for a motor vehicle

Abstract

Safety belt (S) for a motor vehicle, comprising a webbing (1) and a buckle tongue (2) attached thereto, which can be inserted into a buckle (3) and by which the webbing (1) is divided into a lap belt (8) and an upper belt (9), comprising a belt retractor (10, 11) with a belt tensioner by means of which the webbing (1) can be tightened in the event of an accident of the motor vehicle, and a force limiting element (12) by means of which the webbing (1) can be extended if a tensile force caused by an accident is exceeded, wherein the force limiting element (12) is formed by a length section (13) of the upper belt (9), characterized in that the upper belt (9) can be extended between the buckle tongue (3) and the associated belt retractor (10) by means of the force limiting element (12). - wherein the webbing (1) is sewn to the buckle tongue (2) and the waist belt (8) is adjustable in length via a further belt winder (11), and - wherein the length section (13) is fixed to the upper chord (9) by a bridging element (15) which is designed to be flexible when an accident-related tensile force is exceeded.

Description

[0001] The invention relates to a safety belt for a motor vehicle according to the preamble of claim 1.

[0002] Such a safety belt is already known, for example, from DE 94 01 314 U1 and US 2010 / 0 059 980 A1. This three-point belt comprises a webbing and a buckle tongue attached to it, which can be inserted into a buckle. The buckle tongue divides the webbing into an upper webbing section running between the buckle tongue and a belt retractor or a belt guide located above it, and a lap belt section running between the buckle tongue and a belt anchor point. To ensure optimal positioning of the webbing, particularly the upper webbing, in the event of a vehicle accident and to prevent slack, a belt tensioner is provided, which can tighten the webbing in the event of a vehicle accident.

[0003] Such tightening of the seatbelt, or the impulse-induced acceleration and forward displacement that typically occurs during the course of an accident, can, however, lead to injuries to the seated occupant, particularly in the upper body. For this reason, force-limiting elements are already in use, by means of which the seatbelt can be lengthened if a tensile force caused by the accident is exceeded. In the prior art described here, this is achieved, for example, by a section of the lap belt formed by a sewn-together loop, which tears open when a limiting tensile force is exceeded, thus lengthening the lap belt or the seatbelt as a whole.

[0004] Due to the position of the force-limiting element – ​​as in the present case – near the belt retractor or directly within the so-called retractor of the belt retractor, the seat occupant is relieved of stress primarily in the shoulder and upper chest area as a result of the belt's extension. However, it has been shown that a seat occupant is particularly vulnerable to stress in the lower chest and abdominal area as well.

[0005] To limit the load in the area of ​​the lower chest or abdomen, a force limiting element is known from DE 19 03 055 A in the area of ​​the upper sling, which is formed by a belt loop that lengthens when an accident-related tensile force is exceeded.

[0006] A similar force limiting element is also known from DE 10 2015 224 611 A1, which is designed as a metallic curved chicane that deforms and lengthens when a tensile force caused by an accident is exceeded.

[0007] From DE 20 2015 101 561 U1 a webbing of a safety belt is known which in a length range is formed a stretchable band and a non-reversibly stretchable band formed in loops.

[0008] US patent 2008 / 0217457A1 discloses a seatbelt retractor with two spools that can wind and unwind the seatbelt webbing. An inertia-controlled mechanism with a moving mass detects strong vehicle accelerations and automatically locks both spools to prevent further extension of the webbing and thus protect the occupants.

[0009] The object of the present invention is therefore to create a safety belt of the type mentioned above, by means of which the area of ​​the lower chest or abdomen of the respective seat occupant can also be better protected from excessive loads in the event of an accident-related impact.

[0010] This problem is solved according to the invention by a safety belt with the features of claim 1. Advantageous embodiments with favorable further developments of the invention are the subject of the dependent claims.

[0011] To create a safety belt that prevents excessive strain on the occupant's lower chest or abdomen in the event of an accident, the invention provides that the upper webbing between the buckle tongue and the associated belt retractor can be lengthened by means of a force-limiting element. According to the invention, the force-limiting element therefore acts in the area of ​​the upper webbing, i.e., between the buckle tongue and the associated belt retractor, so that, as a result of the force-limiting element, the strain on the occupant, particularly in the area of ​​their lower chest or abdomen, can be significantly reduced. If, accordingly, a tensile force in the area of ​​the upper webbing is exceeded in the event of an accident, the upper webbing between the buckle tongue and the associated belt retractor lengthens accordingly to reduce the force acting on the occupant.to limit any associated breast depression.

[0012] According to the invention, the waist belt is also adjustable in length via an associated belt retractor. Consequently, both the upper belt and the waist belt, which has its own belt retractor, are adjustable in length by means of the associated belt retractor, so that both parts of the webbing – the waist belt and the upper belt – are tightened starting from the buckle tongue attached to the webbing.

[0013] Furthermore, according to the invention, the webbing is sewn to the buckle tongue. This sewing results in a particularly simple and cost-effective attachment of the webbing to the buckle tongue on the one hand, and a fixed division into upper webbing and lap webbing on the other.

[0014] According to the invention, the force-limiting element is formed by a length of the upper chord. This allows the force-limiting element to be created in a particularly simple yet highly effective way.

[0015] Finally, it is also provided according to the invention that the length section on the upper chord is fixed by a bridging element which is designed to be sufficiently flexible when a tensile force caused by an accident is exceeded. This flexibility can be achieved by the bridging element breaking away at one of its attachments / seams to the upper chord, or by providing a predetermined breaking point or the like in an area in between. Theoretically, other types of flexibility for the bridging element would also be conceivable.

[0016] A particularly reliable and effective operation of the force-limiting element can also be achieved if the length of the upper webbing is formed into a loop. If a tensile force caused by an accident is exceeded, the loop can therefore be easily stretched to reduce or limit the force acting on the seat occupant.

[0017] In an advantageous embodiment of the invention, the upper webbing between the buckle tongue and the associated belt retractor can be extended by a length of approximately 50 mm to approximately 150 mm, in particular approximately 90 mm to 110 mm, and preferably approximately 100 mm. Such an extension results in a limitation of the tensile force in an accident that is approximately equally favorable for all seat occupants.

[0018] In a further embodiment of the invention, the upper webbing between the buckle tongue and the associated belt retractor can be extended under a tensile force of approximately 4 kN to approximately 2 kN, and particularly approximately 3 kN, due to an accident. Thus, the described belt force limitation in the area of ​​the upper webbing occurs particularly at approximately 3 kN, so that if this value is exceeded, the webbing extends by, for example, approximately 100 mm. The values ​​described here have proven to be particularly advantageous for seat occupants of all sizes and weights.

[0019] Finally, an embodiment has proven advantageous in which, as an alternative to the length of the upper webbing being looped to form the force-limiting element, a baffle is provided on the buckle tongue through which the upper webbing is guided. The attachment of the upper webbing to the buckle tongue can therefore be designed such that it is held against the baffle on the buckle and, if a corresponding accident-related tensile force is exceeded, can be pulled out or stored within the buckle tongue.

[0020] Further features of the invention will become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures alone, are not only usable in the combinations specified, but also in other combinations or on their own.

[0021] The invention will now be explained in more detail with reference to a preferred embodiment and the drawings. The drawings show: Fig. 1 a perspective view of a seat occupant with a safety belt according to the invention, designed as a three-point belt, the webbing of which is firmly sewn to a buckle tongue and thus divides the webbing into a lap belt and an upper belt, the lengths of which are adjustable via respective belt retractors, Fig. 2 one opposite Fig. 1 enlarged, partial perspective view of the webbing sewn to the buckle tongue, which is divided by the buckle tongue into the waist belt and the upper belt, Fig. 3a, Fig. 3b a schematic side view and a schematic top view of the upper chord, which can be extended by a force limiting element when an accident-related tensile force is exceeded, by means of a length range of the upper chord, which in this case is placed in a loop and fixed by a bridging element, and Fig. 4. A force-displacement diagram of the length range of the upper chord acting as a force-limiting element according to the Fig. 3a and Fig. 3b.

[0022] In Fig. Figure 1 shows a perspective view from a rearward angle of a safety belt S for a passenger in a motor vehicle, represented here by a dummy. The safety belt S, designed as a three-point belt, comprises a webbing 1 to which a buckle tongue 2 is attached.

[0023] The specific fastening of this lock tongue 2 results from Fig. 2, which shows a partial and enlarged view of the safety belt S in the area of ​​the buckle tongue 2 inserted into a buckle 3. The buckle 3 is shown via a view of the Fig. 1 and Fig. 2. Recognizable pulling element 4 is fixed to the vehicle on the unfinished side.

[0024] In this case, the webbing 1 is passed through a slit-like opening 5 of the buckle tongue 2 and sewn by means of a seam 6 forming a loop 7 so that the buckle tongue 2 divides the webbing 1 into a waist belt 8 and an upper belt 9.

[0025] Since the webbing 1 is firmly sewn to the buckle tongue 6 by means of the seam 6, it is necessary in this case to provide both a belt retractor 10 for the upper webbing 9 and a belt retractor 11 for the lap belt 8 in order to achieve length adjustability of the upper webbing 9 and the lap belt 8, respectively. Accordingly, the lap belt 8 and the upper webbing 9 are wound with their respective free ends onto the corresponding belt retractor 11 and 10, respectively. Both belt retractors 10 and 11, for example, have a known mechanism with a corresponding belt tensioner, by means of which the upper webbing 9 and the lap belt 8 can be tightened and subjected to a tensile force, for example, in preparation for an impending impact of the vehicle.

[0026] In order to limit the forces occurring, particularly in the lower chest and abdominal area of ​​the respective occupant, when an accident-related tensile force on the webbing 1, more precisely on the upper webbing 9, is exceeded, these forces arise on the one hand from the tightening of the upper webbing 9 and on the other hand from the impulse-induced forward displacement of the occupant, the present upper webbing 9 has an exemplary feature shown in the Fig. 3a and Fig. Figure 3b shows a force limiting element 12 in a schematic and partial side view or a schematic and partial top view. If, accordingly, a correspondingly high tensile force, which will be explained in more detail below, is exerted on the upper belt 9 as a result of the accident-related forward displacement of the seat occupant and due to the belt tension on both sides, then, if this accident-related tensile force is exceeded, a corresponding elongation of the upper belt 9 occurs, thus limiting the forces acting on the seat occupant in the lower chest area and in the abdominal area.

[0027] In this case, the force-limiting element 12 is formed by a length section 13 of the upper chord strap 9, which is placed in a loop 14. The loop 14 has – as can be seen from Fig. 3a is recognizable - the length l b4 Consequently, a length range 13 of length 2 * l results. b4The upper chord 9 can be extended by a certain amount when a corresponding tensile force is exceeded due to an accident. This extension occurs when a bridging element 15 yields, which secures the loop 14 to the upper chord 9. This bridging element 15 could, for example, be a piece of webbing that is sewn to the upper chord 9 or the corresponding length section 13 at both ends, with at least one of the two seams 16, 17 tearing when the corresponding tensile force is exceeded. Of course, other solutions are also conceivable, such as a band or the like that tears or otherwise yields when a corresponding tensile force is exceeded due to an accident. A reversible yielding of the bridging element 15 would also be theoretically conceivable. Naturally, the bridging element 15 could also be formed in other ways.

[0028] In Fig.Figure 4 shows a schematic force-displacement diagram, which indicates that in the present case the bridging element gives way at approximately 3 kN accident-related tensile force and thus the upper chord 9 stretches by the length range 13 with length 2xl b4 The upper ligament 9 is extended. This extension provides a corresponding degree of flexibility and limits the tensile force occurring within it, thus relieving the area in which the upper ligament 9 runs. This is primarily the area of ​​the lower chest and abdomen.

[0029] The seam 6, which creates the loop 7 to which the buckle tongue 2 is attached, also ensures that an extension of the upper belt strap 9 by the length 13 in the event of an accident exceeding the tensile force does not also result in an extension of the lap belt strap 8. A correspondingly tight fit of the lap belt strap 8 is desirable here, for example, to prevent the occupant from slipping under the lap belt 8.

[0030] The length described here, by which the upper webbing 9 can be extended between the buckle tongue 2 and the associated belt retractor 10, is approximately 100 mm, or between 90 mm and 110 mm, and is merely an example. This range has proven consistently good for all seat occupants of varying sizes, weights, and builds. Even when a range of approximately 50 mm to 150 mm is chosen, sufficiently good results are still achieved.

[0031] Regarding the accident-related tensile force at which the upper chord 9 is elongated by means of the force limiting element 12, values ​​around approximately 3 kN and values ​​in a range between approximately 2 kN and 4 kN have proven advantageous, as these take into account the previously described, different seat occupants in a particularly advantageous way.

[0032] In a further embodiment of the invention, the extension of the upper webbing 9 by means of the force limiting element 12 can be achieved not only by the length section 13 described here, which is placed in the loop 14, but, for example, by a length section of the upper webbing 9 that is guided by a baffle provided on the buckle tongue 2. Consequently, if an excessive, accident-related tensile force is exerted on the upper webbing 9, the webbing 1, which is itself fixed to the baffle of the buckle tongue 2, is moved or extended relative to the baffle in order to achieve the desired extension of the upper webbing 9 between the buckle tongue 2 and the associated belt retractor 10. Reference symbol list 1 webbing strap 2 Lock tongue 3 Seatbelt buckle 4 Pull element 5 Opening 6 seam 7 loops 8. Hip belt 9 Upper girth strap 10 belt retractors for upper webbing 11 belt retractors for lap belt 12 Force limiting element 13 Length range 14 loops 15 Bridging element 16th seam 17th seam S safety belt

Claims

[1] Seat belt (S) for a motor vehicle, comprising a webbing (1) and a buckle tongue (2) attached thereto, which can be inserted into a buckle (3) and by which the webbing (1) is divided into a lap belt (8) and an upper belt (9), comprising a belt retractor (10, 11) with a belt tensioner by means of which the webbing (1) can be tightened in the event of an accident of the motor vehicle, and with a force limiting element (12) by means of which the webbing (1) can be extended if a tensile force resulting from an accident is exceeded, wherein the force limiting element (12) is formed by a length section (13) of the upper belt (9), characterized by , that the upper belt strap (9) between the locking tongue (3) and the associated belt winder (10) can be extended by means of the force limiting element (12), - wherein the webbing (1) is sewn to the buckle tongue (2) and the waist belt (8) is adjustable in length via a further belt winder (11), and - wherein the length section (13) is fixed to the upper chord (9) by a bridging element (15) which is designed to be flexible when an accident-related tensile force is exceeded. [2] Safety belt (S) according to claim 1, characterized by , that the length section (13) of the upper webbing (9) is placed in a loop (7). [3] Safety belt (S) according to any one of the preceding claims, characterized by , that the upper webbing (9) between the locking tongue (2) and the associated webbing retractor (10) can be extended by a length of approximately 50 mm to 150 mm. [4] Safety belt (S) according to any one of the preceding claims, characterized by, that the upper webbing (9) between the locking tongue (2) and the associated webbing retractor (10) can be extended by a length of approximately 90 mm to 110 mm. [5] Safety belt (S) according to any one of the preceding claims, characterized by , that the upper belt strap (9) between the locking tongue (2) and the associated belt retractor (10) can be extended to approximately 2 kN under an accident-related tensile force of approximately 4 kN. [6] Safety belt (S) according to any one of the preceding claims, characterized by , that the upper belt strap (9) between the locking tongue (2) and the associated belt retractor (10) can be extended to approximately 3 kN under an accident-related tensile force of approximately 4 kN. [7] Safety belt (S) according to claim 1, characterized by , that the force limiting element (12) is formed by a baffle for the upper chord strap (9) provided on the lock tongue (2).

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