JP3394577B2 - Seat belt webbing - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt webbing for restraining and protecting an occupant of a vehicle such as an automobile in an emergency. The present invention relates to a seat belt webbing for safer protection of an occupant.

[0002]

2. Description of the Related Art Conventionally, as a webbing of this type of seat belt, as shown in FIG. 3, a webbing 1 in which an intermediate portion is folded and sewn is used. That is, by repeating the process in which the folded webbing 1 is sewn in the width direction with the sewing thread 2, and the side edges of the webbing 1 are sewn in the longitudinal direction, inverted, and sewn in the width direction. The sewn portion 3 was formed over the required length. In the webbing thus produced, the load at which the sewn portion breaks is determined by the strength of the sewing thread sewn in the width direction and the number of stitches moved, and the number of stitches in the width direction is added to this to determine the sewn portion. The total amount of energy that can be absorbed is determined. Therefore, in order to continuously sew the sewing thread a plurality of times in the width direction of the webbing, the sewing is performed so that the webbing side edge portion is once sewn in the longitudinal direction and then folded back. Also, this kind of webbing is
Since it is intended to absorb the impact load only by breaking the sewing thread at the sewn part, the strength of the sewing thread is considerably higher than that of the thread forming the webbing, and in order to increase the utilization rate of the sewing thread, As the upper thread and the lower thread to be constructed, a thread having almost no twist is used. Then, when an impact load is applied to the webbing, as shown in FIG. 4, a force is applied to the sewing portion 3 to the upper thread 5 and the lower thread 6 constituting the sewing thread 2 so as to tear the sewing base end portion 4, The sewing thread 2 is sequentially broken from the sewing base end portion 4 toward the sewing front end portion 7 to absorb the impact load.

[0003]

The breaking strength of the sewn portion is set according to the vehicle type, and various types are required, from those that break under a low load to those that break under a very high load. Then, usually, by increasing or decreasing the number of stitches of the sewing thread in the width direction of the webbing, a sewn portion corresponding to these various types is formed. However, since the width of the webbing is constant, there is a limit to the number of hands that can be moved, and it is impossible to increase the breaking load of the sewn portion beyond a predetermined value. Therefore, in order to further increase the breaking load of the sewn portion, the strength of the sewing thread itself must be increased. However, if the strength of the sewing thread is simply increased as described above, the weft thread constituting the webbing is broken at the side edge portion of the webbing after the sewn portion is broken, and the warp thread may not be textured to cause fraying. there were. Therefore, the breaking load of the sewn portion cannot be freely set.

The breakage of the weft thread of the webbing occurs at the folding back portion of the sewing thread at the side edge portion of the webbing (the portion where the sewing thread is sewn in the longitudinal direction at the side edge portion of the webbing). Since the sewing thread is sewn so as to straddle the weft thread of the webbing at the folded back portion of the sewing thread, the upper thread 5 on the surface of the sewing portion 3 is sewn when a pulling force is applied, as shown in FIG. It was found that the lower thread 6 on the back surface of the portion 3 was pulled up and the weft thread of the webbing 1 was strongly rubbed by the lower thread 6. Especially for seat belt webbing,
Since only the warp threads are exposed on the surface in order to improve the slippage of the surface, when a load is applied to the sewn portion, the thread along the side edge of the webbing, which runs parallel to the warp thread, easily enters between the warp threads. Up to the folded portion of the sewing thread, the sewing thread enters between the warp threads of the webbing, so the warp thread is pressed and it is difficult to open the mesh, but outside the folded portion, the warp thread of the webbing can move relatively freely, so it is easy to open the mesh. The sewing thread easily enters between the warp threads. Therefore, breakage easily occurs along the folded-back portion. By the way, when all the impacts cannot be absorbed by the sewn part, after all the sewing threads in the sewn part are broken, it is necessary to safely protect the occupant like the normal webbing. If the weft yarn of the webbing breaks and only part of the warp yarn is unstructured when it breaks, the load applied to the entire warp yarn of the webbing becomes uneven, which leads to a reduction in the strength of the webbing, which is not preferable.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to provide a sewn portion for shock absorption even when a sewing thread is broken. It is an object of the present invention to provide a seat belt webbing without damaging the webbing itself.

[0006]

In order to achieve the above object, the seat belt webbing according to the present invention is formed by weaving an intermediate portion of the webbing formed by weaving warp threads and weft threads, and sewing the same to an occupant in an emergency. In a seat belt webbing that absorbs an impact load applied by breaking the sewing thread of the sewing section, the sewing section is sewn substantially parallel to the weft thread of the webbing, and the side edge of the webbing is bent over and inverted. It is formed by repeating the step of sewing substantially parallel to the weft thread of the webbing and performing continuous sewing.
Further, in the webbing of a seat belt, the intermediate portion of a webbing formed by weaving warp threads and weft threads is folded and sewn, and the impact load applied to an occupant in an emergency is absorbed by breaking the sewing thread of the sewn portion. The lower thread of the sewing thread of the wearing part is 2000-3000D and 250-350 times /
m is a twisted yarn and is thicker than the webbing warp yarn. And the lower thread of the sewing thread of this sewing part is 3
00 to 600 times / m Draw a plurality of ply-twisted yarns for 2
It is a thread that is twisted at 50 to 350 times / m.

[0007]

Since the sewn portion is sewn substantially parallel to the weft of the webbing and the side edges of the webbing are bent and continuously sewn, the sewing thread does not become parallel to the warp of the webbing. Then, since the upper thread and the lower thread of the sewing thread intersect at the side surface of the webbing and restrain the warp thread on the side edge of the webbing, the warp thread does not open. Therefore, even if an impact load is applied to the webbing, the sewing thread does not dig into between the warp threads. In addition, the thickness of the lower thread of the sewing thread of the sewing portion is 2000 to 3
By using a yarn with a twist of 000D and 250 to 350 turns / m, the cross section becomes rounder and more rigid than a yarn with almost no twist, so the lower thread pulls on the upper thread when the sewing thread breaks. Even if it is broken, it is difficult for the webbing to enter between the warp threads. If a pretwisted product is twisted and used as a bobbin thread, the apparent cross section becomes further larger, and it is difficult for the webbing to enter between warp threads.

[0008]

EXAMPLES Examples will be described with reference to the drawings. FIG. 1 is a front view of a seat belt webbing 10 according to the present invention. The webbing 10 is formed by weaving warp yarns and weft yarns, and the same material as that conventionally provided for seat belts may be used. In this example, 332 polyester threads of 1260D / 108F were used as the warp threads, and two polyester threads of 500D / 96F were aligned as the weft threads, and were woven at an interval of 19.5 threads / 25 mm.

The intermediate portion of the webbing 10 has a sewn portion 12 formed by folding the webbing 10 and sewing it with a sewing thread 11. That is, the sewing thread 11 is sewn substantially parallel to the weft thread of the webbing 10, and the step of continuously stitching the side edge 13 of the webbing 10 is repeated to repeat the step of sewing the sewn portion 12 over the required length. Has been formed. When an impact load is applied to the occupant in an emergency, the sewing thread 1 of the sewing portion 12
1 breaks from the sewn base end 14 and the shock is absorbed.

FIG. 2 is a front view of a seat belt webbing 20 according to another embodiment. This webbing 20
In addition, the warp yarn and the weft yarn are woven, and the same material as that of the above-mentioned embodiment is used. The intermediate portion of the webbing 20 is folded and sewn with a sewing thread 21 to form a sewing portion 22. That is, the sewing thread 21 is sewn substantially in parallel with the weft thread of the webbing 20, and the side edge portion 23 of the webbing 20 is bent and sewn in the longitudinal direction of the webbing 20 while being reversed and the weft thread in the width direction of the webbing 20. The sewn portion 22 is formed over a required length by repeating the step of sewing substantially in parallel with.

And in this embodiment, the sewing thread 21
Even if the lower thread is pulled by the upper thread when the webbing breaks, the webbing 20
In order to make it difficult for the sewing thread 21 to enter between the warp threads, the sewing thread 2
The thickness of the lower thread of 1 is 2000-3000D and 25
A yarn with a twist of 0 to 350 turns / m is used. Also,
As the lower thread, a thread may be used in which a plurality of threads twisted under 300 to 600 times / m are aligned and subjected to a twist of 250 to 350 times / m.

Next, a breaking test was conducted, and the test results will be described. In Example 1, a 630D / 3 polyester thread (1890D) was used as the lower thread of the sewing thread, and a 630D / 3 polyester thread (1890D) was used as the upper thread. Needle sewing and empty stitching at the side edge of the webbing to entangle the upper thread and the lower thread, and then sew in the width direction of the webbing at a distance of 3 mm from the previous sewing portion, The sewn portion was repeatedly formed as shown in FIG.

In the second embodiment, 1000D is used as the lower thread of the sewing thread.
20 needle stitches at 2.2 mm pitch in the width direction of the webbing on the sewing machine, using 3/4 twisted polyester yarn (2000D) 340 times / m and 630D / 3 polyester yarn (1890D) as the upper thread. And sew 3 mm along the side edge of the webbing in the longitudinal direction of the webbing and fold it back, and then sew it upside down in the width direction of the webbing,
By repeating this, the sewn portion was formed as shown in FIG.

In Example 3, polyester yarn 250D / 3 was twisted 518 times / m as the lower thread of the sewing thread, and then three pieces of the polyester thread 250D / 3 were twisted and twisted 278 times / m (2250).
D, apparent 2768D), and 630D / 3 polyester thread (1890D) were used as the upper thread to form a sewn portion in the same manner as in Example 2.

In the comparative example, the lower thread of the sewing thread is 630D / 3.
A sewn portion was formed in the same manner as in Example 2 by using the polyester thread (1890D) of No. 1 above, twisted 150 times / m and using the polyester thread of 630D / 3 (1890D) as the upper thread. All the upper yarns used were twisted at 150 times / m.

The results of a breaking test with both ends of these webbings fixed are as follows. Results Example 1: No weft breakage of webbing (breaking load) 352 kg Example 2: No weft breakage of webbing (breaking load)
330 kg Example 3: No breakage of webbing weft yarn (breaking load)
345 kg Comparative Example: Breakage due to weft yarn breakage at the side edge of the webbing (breaking load) 310 kg

In Examples 2 and 3, the lower thread preferably has a fineness in the range of 2000 to 3000D, and the upper twist is 250 to 350 times / m in order to make it sufficiently thick and rigid. It was found that When the bobbin thread exceeds 3000D, it is difficult to supply it from the bobbin at the time of sewing, and when the upper twist is 250 times / m or less, sufficient rigidity cannot be obtained, and when it is 350 times / m or more, sufficient thickness can be obtained. It turned out not to be. Also, as the lower thread, 3
When a plurality of twisted yarns having a relatively large number of twists of 0 to 600 times / m are twisted together, the apparent thickness is increased, and a more preferable one is obtained.

When the sewn portion is broken, the upper thread of the sewing thread mainly breaks. However, even though the same upper thread is used for all, as shown in the above results, all of the examples are compared. The breaking strength is higher than the example. This is considered to be due to the following. In Example 1, it is considered that two empty stitches at the green side edges in the width direction of the webbing enhance the breaking strength substantially corresponding to the needle movement. In Example 2, since the cross section of the lower thread is thick and round, the breaking strength of the upper thread against the lower thread is higher than that of the comparative example. In Example 3, since the cross section of the lower thread is thicker and rounder, higher breaking strength than in Example 2 is obtained.

[0019]

The present invention is configured as described above,
Even when the lower thread is pulled by the upper thread when the sewn portion of the webbing is broken, the lower thread does not enter between the warp threads of the webbing, so that the webbing is not damaged. Therefore, the webbing itself will not be damaged when the sewing thread is broken even if the sewing portion for absorbing shock is provided. Therefore, it is possible to form a sewn portion having a higher breaking load than the conventional one.

[Brief description of drawings]

FIG. 1 is a front view of a webbing according to the present invention.

FIG. 2 is a front view of another embodiment of webbing.

FIG. 3 is a perspective view of a conventional webbing.

FIG. 4 is a side view of a conventional example when a sewn portion starts to break.

[Explanation of symbols]

10,11 Webbing 11,21 sewing thread 12,22 Sewing part 13 side edge 23 Side edge

Claims (3)

(57) [Claims] 1. A seat belt webbing which absorbs an impact load applied to an occupant in an emergency by breaking the sewing thread of the sewn portion, by folding and sewing the intermediate portion of the webbing formed by weaving warp threads and weft threads. Formed by repeating the steps of sewing the sewn portion substantially in parallel with the weft thread of the webbing, overturning the side edge of the webbing and reversing it, and sewing substantially parallel to the weft thread of the webbing. The webbing of the seat belt characterized by having done. 2. A seat belt webbing, wherein an intermediate portion of a webbing formed by weaving warp threads and weft threads is folded and sewn, and an impact load applied to an occupant in an emergency is absorbed by breaking the sewing thread in the sewn portion. , The lower thread of the sewing thread of the sewing portion has a thickness of 2000 to 3000D and 250 to 3
A webbing for a seat belt, which is a thread twisted 50 times / m and is thicker than the warp thread of the webbing. 3. The lower thread of the sewing thread of the sewing portion is 300 to 60.
250 times to 35 times by arranging multiple twisted yarns 0 times / m
The webbing of a seat belt according to claim 2, wherein the yarn is a twisted yarn of 0 times / m.