DE102012003409A1 - Tear stitching for interconnecting portions of e.g. passenger frontal airbag, to protect occupant of vehicle, has two end portions extending from leg portions, where stitching exhibits high and low rupture strength based on tension forces - Google Patents

Abstract

The stitching has a central portion extending between two end portions, where the central portion comprises two leg portions that converge at an angle and intersect a break point. Each end portion extends from the respective leg portion along a path that diverges from the path of the corresponding leg portions, where the stitching exhibits high rupture strength in response to tension forces applied to interconnected portions that act on the end portions, and exhibits low rupture strength based on tension forces applied to interconnected portions that act on the break point. An independent claim is also included for an apparatus for helping to protect an occupant of a vehicle.

Description

The present invention relates to a device for protecting an occupant of a vehicle. More particularly, the present invention relates to an inflatable vehicle occupant protection device inflatable between a dashboard and a vehicle occupant in the front seat of a vehicle, and more particularly to a tear seam for such an inflatable vehicle occupant protection device.

It is known, an inflatable vehicle occupant protection device such. As an airbag to provide for the protection of a vehicle occupant. One particular type of airbag is a frontal airbag that is inflatable between a vehicle occupant on a front seat of the vehicle and a dashboard of the vehicle. Such airbags may be either driver or passenger airbags. When inflated, the driver and passenger airbags protect the occupant from impact with vehicle parts such as the dashboard and / or the steering wheel of the vehicle.

Passenger airbags are usually stowed in a deflated state in a mounted on the vehicle dashboard housing. An airbag door may be connected to the housing and / or the dashboard to enclose and conceal the airbag when stowed. Upon deployment of the passenger airbag, the airbag door opens, allowing the airbag to assume an inflated position. The airbag door opens due to forces exerted by the inflating airbag on the flap.

Driver airbags are normally stowed in a deflated state in a housing attached to the vehicle wheel. An airbag cover may be connected to the housing and / or the steering wheel to enclose and conceal the airbag in the stowed condition. Upon deployment of the driver's airbag, the airbag cover opens, allowing the airbag to assume an inflated position. The airbag cover opens due to forces exerted by the inflating driver's airbag on the cover.

The present invention relates to a tear seam for joining portions of an inflatable vehicle occupant protection device. The tear seam preferably has a first and second end portion of rolled-up shape and a middle portion extending between the end portions. The middle section preferably has leg sections which converge at an angle and intersect a break point. The tear seam preferably has a comparatively high tear strength as a function of tensile forces applied to the interconnected sections which act on the end sections of the tear seam. The tear seam preferably has a comparatively low tear strength as a function of tensile forces applied to the interconnected sections, which act on the break point of the tear seam.

Preferably, the leg portions of the central portion are arranged V-shaped. Further preferably, the first and second end portions are inwardly rolled relative to the V-shape of the central portion and toward the point of breakage.

Preferably, the first and second end portions have a rolled-up shape. More preferably, the rolled-up shape of the first and second end portions is selected such that the ends of the first and second portions are hidden from tension forces applied to the interconnected portions, which act on the end portions of the tear stitching.

According to a preferred embodiment, the leg portions are convexly curved away from each other.

It is preferred that the end portions are rolled inwardly more than ninety degrees from their respective interfaces to the central portion.

More preferably, the end portions are curled inwardly more than one hundred and eighty degrees from their respective interfaces to the central portion. More preferably, the end portions are curled inwardly more than two hundred and seventy degrees from their respective interfaces to the central portion. According to a preferred embodiment, the break point has a single stitch.

The leg portions preferably extend away from each other and away from the breakpoint.

According to a preferred embodiment, the break point has a plurality of stitches which are arranged in a line and which extend transversely to the leg portions.

Here it is preferred that the break point has at most two stitches. It is further preferred that the leg sections extend away from each other and away from the breakpoint.

According to a preferred embodiment, the sections of the protective device comprise first and second sections of the protective device, which are arranged superimposed, wherein the Tear seam passes through and connects the first and second portions, the first portion having a first material segment and the second portion having a second material segment extending away from the end portions of the tear seam in a first direction and a third material segment extending away from the breaking point of the tear seam in a second direction; wherein preferably the sections of the protective device and the tear seam are constructed and arranged such that a tension applied to the first and second segments generates a shearing force directed towards the end sections, the tear seam thus having a comparatively high tear resistance; and / or wherein preferably the sections of the protective device and the tear seam are constructed and arranged in such a way that the tension applied to the first and third segments generates a peel force which is directed to the break point, the tear seam thus having a comparatively low tear resistance. According to a preferred embodiment, the tear seam is further provided with a self-releasing portion, which is designed so that it is subjected to the interconnected portions acting, initial tension forces, preferably the tear seam is designed such that a tearing of the self-releasing portion in response initial voltage increase between the interconnected portions, with the self-releasing portion receiving the initial rise and the remainder of the tear seam being subject to the tension forces after the initial rise decreases, thus being able to withstand the tension forces without tearing. Preferably, the self-releasing portion is disposed adjacent the fracture site, wherein the tear seam is configured such that the self-releasing portion is subjected to stress between the portions and tears depending on the tension forces before the tension forces act on the fracture site.

Preferably, the self-releasing portion has at least one V-shaped seam portion which is inserted around the break point.

According to a preferred embodiment, the first and second end portions have a rolled-up shape, preferably the rolled-up shape of the first and second end portions being selected such that the ends of the first and second end portions are hidden from the tension forces applied to the interconnected portions the end portions of the tear seam act.

The present invention further relates to a device for protecting a vehicle occupant. The apparatus includes an inflatable vehicle occupant protection device having a deflated condition and an inflated condition. A tear seam connects sections of the protective device. The tear seam has at least one of the features described above. For example, it has a first end portion of rolled-up shape, a second end portion of rolled-up shape, and a middle portion extending between the end portions. The middle section has leg portions which converge at an angle and intersect a break point. The tear seam has a comparatively high tear resistance as a function of tensile forces applied to the interconnected sections, which act on the end sections of the tear seam. The tear seam has a comparatively low tear strength as a function of tensile forces applied to the interconnected sections, which act on the break point of the tear seam.

The present invention further relates to a vehicle safety system having such an inflatable vehicle occupant protection device. It also includes an actuator assembly, particularly with a gas generator, for inflating the vehicle occupant protection device. Preferably, an electrical activation unit is provided which is signal-connected to the actuator assembly such that an electrical trigger pulse is transferable to the actuator assembly. Further preferably, at least one sensor for detecting vehicle movement data is connected to the activation unit. The activation unit is preferably designed to transmit the electrical triggering pulse as a function of the measured vehicle movement data to the actuator assembly, in particular the gas generator.

Further features of the invention are the subject of the respective subclaims.

The foregoing and other features of the present invention will become apparent to those skilled in the art upon consideration of the following description of the invention with reference to the accompanying drawings.

Show it:

1 a schematic side view of a device for protecting a vehicle occupant;

2 and 3 a tear seam, which is used to connect sections of the device 1 is used according to the present invention;

4 an enlarged view of a portion of the tear seam from the 2 and 3 ;

5A to 5D Representations of exemplary embodiments for certain portions of the tear seam;

6A and 6B Illustrations for comparing different configurations for certain sections of the tear seam;

7A and 7B Illustrations for comparing different configurations for certain sections of the tear seam;

8A and 8B Illustrations for comparing different configurations for certain sections of the tear seam;

9A to 9C Illustrations for comparing different configurations for certain sections of the tear seam;

10 a diagram illustrating certain properties for different designs of tear seam;

11 and 12 schematic side views illustrating an exemplary use of the tear seam according to the present invention.

A device 10 to protect an occupant 20 of a vehicle 12 includes an inflatable vehicle occupant protection device 14 in the form of an airbag. In the in 1 illustrated embodiment, the airbag 14 a passenger frontal airbag to protect an occupant 20 on a seat 22 on the passenger side 24 of the vehicle 12 ,

The airbag 14 can be part of an airbag module 30 which is a gas generator 32 and a housing 34 having. The airbag 14 includes a dashed line in 1 indicated, stowed state in which the airbag folded and in the housing 34 is placed. The module 30 is on a dashboard 36 of the vehicle 12 appropriate. The housing 34 contains and supports the airbag 14 as well as the gas generator 32 in the dashboard 36 ,

An airbag flap 40 is detachable with the dashboard 36 and / or the housing 34 connected. In a closed state (not shown) forms the airbag flap 40 a cover for the module 30 and encloses the airbag 14 in the stowed state in the housing 34 , The flap 40 is in an in 1 illustrated, open state movable to an opening 44 expose through which the airbag 14 from the stowed state in the housing 34 can unfold. The flap 40 can be either directly or through the case 34 by means (not shown) such as a plastic joint part, a band or a tether with the vehicle 12 , z. B. the dashboard 36 be connected.

The gas generator 32 can be used to provide filling medium in an inflatable volume 54 of the airbag 14 be actuated so that the airbag unfolds in the inflated state. It can be any known type of gas generator 32 be used, such. As stored gas, solid fuel, in enriched or hybrid form. The device 10 has a schematic with 50 illustrated sensor for detecting an event, the inflation of the airbag 14 requires, such. B. cm collision. The gas generator 32 stands with the sensor 50 via connecting lines 52 in active connection.

The airbag 14 may be made of any suitable material, such as nylon (e.g., 6-6 ply nylon webbing), and of any suitable construction. For example, the airbag 14 consist of one or more pieces of material or webs containing the inflatable volume 54 of the airbag. If multiple pieces or webs are used, they may be joined together by known means such as stitching, ultrasonic welding, heat sealing or adhesives to form the airbag. The airbag 14 can be either uncoated, with a material such. B. gas impermeable urethane or coated with a material such. B. laminated to a gas-impermeable film. Thus, the airbag 14 have a gas-tight or substantially gas-tight construction. Those skilled in the art will recognize that alternative materials such as polyester yarn as well as alternative coatings such as silicone for building the airbag 14 can be used.

Once the occurrence of an event is detected, the inflation of the airbag 14 requires, such. B. a vehicle crash, transmits the sensor 50 over the connecting lines 52 a signal to the gas generator 32 , Upon receipt of the signal from the sensor 50 becomes the gas generator 32 operates and adjusts the inflatable volume 54 of the airbag 14 Ready in a known manner filling medium. The inflating airbag 14 exerts a force on the cover 40 off, which puts them in the open state. The airbag 14 inflates from the stowed state to an unfolded state, such as, e.g. B. the in 1 shown in solid lines, fully inflated and unfolded state. The airbag 14 protects the vehicle occupants 20 in the inflated state before an impact on parts of the vehicle 12 like the dashboard 36 ,

The airbag 14 may include one or more actuation features for controlling or adjusting the inflation of the airbag as a function of Vehicle conditions, occupant conditions or both. These features may be actuated either actively, for example, depending on conditions determined by active sensors, or passively, for example, in an embodiment responsive to physical conditions at the time of inflation.

According to the present invention, the device has a rupturable tear seam which can promote these actuation features. The rupturable tear seam of the present invention promotes predictability, repeatability, and reliability in releasably securing interconnected portions of the guard 14 ,

Referring to the 2 and 3 connects the rupturable tear seam 100 according to the present invention, a first section 130 the protective device 14 with a second section 140 the protective device. The first and second sections 130 and 140 the protective device 14 may consist of any portion of the device for which a detachable connection may be desired. The first and second sections 130 and 140 For example, in the inflatable volume 54 of the airbag 14 be attached tethers. Alternatively, the first and second sections 130 and 140 Sections of one or more webs leading to the construction of the airbag 14 be used. As another alternative can. the first and second sections 130 and 140 consist of a combination of airbag tracks and tethers.

The seam 100 has a first end portion 102 and an opposite, second end portion 104 and a middle section 110 on, which runs between the end sections. The middle section 110 has first and second leg portions 112 respectively. 114 which converge at an angle and cross a break point. In the in the 2 and 3 illustrated embodiment, the leg portions 112 and 114 of the middle section 110 arranged in a generally V-shaped configuration and are convexly curved away from each other. The leg sections 112 and 114 thus lie opposite each other concave.

In the in the 2 and 3 illustrated embodiment, the first and second end portions 102 and 104 designed so that they are from the path of the leg sections 112 and 114 vary to increase the tear strength of the end sections. In particular, the end sections 102 and 104 in the embodiment of the 2 and 3 generally rounded and rolled-up embodiments. In this embodiment, the end portions 102 and 104 in relation to the V-shape of the middle section 110 rolled inwards and into the room, on which the leg sections 112 and 114 are directed concavely. The end sections 102 and 104 are thus inward to each other and down to the breaking point 116 curved or rolled up.

Appropriate ends 106 and 108 the end sections 102 and 104 are positioned within the curvature of the end sections. By "within the curvature" of the end portions is meant that the ends 106 and 108 with respect to the central axis 118 the seam 100 in or between horizontal outer borders of the end sections 102 respectively. 104 are positioned.

The position of the ends 106 and 108 within the curvature of the end sections 102 and 104 depends on the degree or extent to which the end portions of the leg portions 112 and 114 are curved inwardly, measured from their respective interfaces to the leg sections. For example, in relation to 4 can the end section 104 at least 90 degrees (90 °) inward from its interface (generally designated "1") to the leg portion 114 being rolled up, causing its end at or outside of the generally with 108 ' in 4 designated place is placed. Alternatively, the end portion 104 rolled at least one hundred eighty degrees (180 °) inwards, causing its end at or outside of the generally with 108 '' designated place in 4 is placed. As a further alternative, the end portion 104 rolled at least two hundred and seventy degrees (270 °) inwards, thus making its end at or outside of the generally with 108 '' designated place in 4 is placed. While in 4 only the end section 104 and its associated end 108 and the leg section 114 those skilled in the art will recognize that the end portion 102 and its associated end 106 and the leg section 114 would have identical properties.

Advantageously, the rolled-up design improves or maintains the end sections 102 and 104 the complete shear strength of the tear seam 100 , The end sections 102 and 104 do this by holding the ends 106 and 108 in the respective roll margins "hide". Hiding the ends 106 and 108 in this way prevents the first and second segments 150 and 152 applied tensile forces are focused on the ends. This prevents premature tearing and the predictability, repeatability and reliability of the connection between the tearing seams 100 provided sections 130 and 140 is funded.

It will be appreciated by those skilled in the art that the concealing of the end portions also applies to shapes other than those of the inwardly curled shape 2 and 3 shown species can be achieved. For example, the curled configuration may have different shapes, such as a further curvature (eg, larger radius) or a narrower curvature (eg, reduced radius). Additionally or alternatively, the end portions may have a curvature that varies in the degree or direction of the curvature.

The break point 116 can have different shapes, of which in the 5A - 5D Examples are shown. The 5A - 5D show in detail the middle section 110 the seam 100 where the leg sections 112 and 114 at the break point 116 converge. Referring to the 5A - 5D , there is the seam 100 from a variety of individual stitches 120 which the leg sections 112 and 114 as well as the break point 116 form. The break point 116 is along the axis 118 measured the bottom of the seam 100 ,

In the embodiment of the 5A becomes the break point 116 from a single stitch 122 formed, the last stitch of the first leg section 112 represents. From that the break point 116 forming stitch 122 From the next stitch begins, namely first stitch of the second leg section 114 , along the axis 118 measured vertically above the break point.

In the embodiment according to 5B becomes the break point 116 from a pair of stitches 124 educated. One of the stitches 124 is the last stitch of the first leg section 112 of the middle section 110 , and the other stitch 124 is the last stitch of the second leg section 114 of the middle section 110 , In the 5B the break point 116 forming stitches 124 ends along the axis 118 measured at or about the same vertical location and are even or substantially uniform from the axis 118 spaced.

In the embodiment according to 5C becomes the break point 116 through a single stitch 126 educated. The sting 126 extends transversely to the first and the second leg portion 112 and 114 and perpendicular to the axis 118 , The sting 126 extends over the axis 118 and connects to the end stitches of the first and second leg portions 112 and 114 ,

In the embodiment of the 5D is the break point 116 through several stitches 128 formed, namely two stitches in this embodiment. The stitches 128 extend transversely to both the first and the second leg portion 112 and 114 and perpendicular to the axis 118 , One of the stitches 128 Adjacent to the endstitch of the first leg section 112 on, and the other of the stitches 128 adjoins the last stitch of the second leg section 114 , Although in the embodiment of the 5D two stitches 128 those skilled in the art will recognize that the fracture site 116 Also, a larger number of stitches, ie, three or more stitches may have.

As in the 2 and 3 shown, shares the tear seam 100 the second section 140 the protective device 14 into two segments, resulting in three interconnected material segments. A first segment 150 consists of the first section 130 , The second and third segments 152 respectively. 154 consist of sections of the second section 140 on opposite sides of the tear seam 100 , The on the first segment 150 applied stress is generally indicated by the arrowhead marked "A" in FIG 2 specified. The on the second segment 152 applied stress is generally indicated by the arrowhead marked "B" in FIG 2 specified. The on the third segment 154 applied stress is generally indicated by the arrowhead marked "C" in FIG 2 specified.

The tear seam 100 is designed so that it ruptures and the connection between the first and second section 130 and 140 as a function of the voltage between the first and second sections. According to the present invention, the tear seam 100 suitable, the connection between the first and second section 130 and 140 depending on which of the first, second and third segments 150 . 152 and 154 is tensioned, and the amount of tension in these segments.

As in the example of 2 and 3 shown, the voltage acts between the first and second segments 150 and 152 on the tear seam 100 in a way different from the tension between the first and third segments 150 and 154 different. Of course, the tension between the second and third segment 152 and 154 not on the tear seam 100 because these segments consist of the same piece of material, ie the second section 140 the protective device 14 , The person skilled in the art will recognize that the relative directions A, B and C, in which the stress on the segments 150 . 152 and 154 is applied, depending on the design of the protective device 14 and the equality of the sections 130 and 140 may vary, which is due to the tear seam 100 connected to each other. However, as the sections 130 and 140 are made of flexible materials, it will be appreciated by those skilled in the art that the sections will self-align under tension in the direction A-B or A-C, so that these particular stress scenarios are identical or substantially identical to the tear seam 100 Act.

In particular, the voltage acts in the case of between the first and second segments 150 and 152 applied stress, generally parallel to the overlapping portions of the first and second sections 130 and 140 passing through the seam 100 are held together. One on the first and second segment 150 and 152 applied force is thus essentially shearing over the tear seam 100 applied. The tear seam 100 is constructed so that it pulls over the tear seam 100 distributed and in particular over the curved leg sections 112 and 114 and the rolled-up end sections 102 and 104 , Consequently, the tear seam points 100 depending on the first and second segment 150 and 152 applied stress due to the stress distribution over the curved segment a comparatively high tensile strength. This is referred to herein as "shear strength".

If there is a voltage between the first and third segments 150 and 154 is applied, the tension acts at an angle or across the overlapping portions of the first and second sections 130 and 140 passing through the seam 100 are held together. The tension between the first and third segments 150 and 154 thus creates a "peel" force or action between the first and second sections 130 and 140 at the interface of the first and third segments 150 and 154 , The tear seam is designed so that the peel effect the tensile forces on the break point 136 the tear seam 132 directed. Consequently, the tear seam points 100 depending on the first and third segment 150 and 154 applied stress a comparatively low tensile strength due to the focus of the voltage on the break point on. This is referred to herein as "peel strength".

From the above, the skilled artisan recognizes that the tear seam 100 the present invention provides a comparatively high shear strength and a relatively low peel strength. If on the first and second segment 150 and 152 Tension is applied, the tensile forces over a large section or area of the tear seam 100 applied. Thus, the stress must overcome the combined strength of several individual stitches to increase the shear strength of the tear seam 100 to overcome and the gradual tearing of the remaining stitches to begin, the separation of the first and second sections 130 and 140 the protective device 14 leads.

Conversely, the tensile forces when tension on the first and third segments 150 and 154 is applied to the peel effect, which reduces the tensile forces on the break point 116 directed. Thus, the tension must overcome the strength of the single, or relatively few, single stitches that break 116 form the shear strength of the tear seam 100 to overcome. Once the break point 116 tears, the crack settles rapidly along the leg sections 112 and 114 which led to the separation of the first and second sections 130 and 140 the protective device 14 leads.

According to the present invention, the shear strength and the peel strength of the tear stitching 100 be tailored to desired values via a variety of customizable properties. Through experimentation, it has been found that careful selection of particular combinations of these properties results in a tear seam having a desired combination of shear and peel strengths. These properties include the shape of the tear seam 100 , the type of thread used to form the tear seam, and the type of material used to make the sections connected by the seam 130 and 140 is used. To evaluate the effects these properties have on the shear strength and peel strength of the seam, the tests were directed to specific properties to determine the effects, if any, of these particular properties on shear strength, peel strength, or both peel - as well as the shear strength had.

Tip breakage compared to flat fracture site

The 6A and 6B illustrate sharp and shallow fractures 202 respectively. 212 , Attempts have been made to detect the effects of a sharp break point 202 (please refer 6A ) compared to a flattened break point 212 (please refer 6B ) on the peel strength and shear strength of the tear seam 200 respectively. 210 to determine. To focus the experiments on the fracture site, the trials were conducted on a V-shaped seam with no rolled-up or rounded end portions facing the fracture sites 202 and 212 and with straight leg sections 204 respectively. 214 carried out. In carrying out these tests, the factors evaluated were the suture strength of the suture, the weight of tissue used to make the interconnected sections, the issue of whether the tissue was coated, and the shape (pointed or flat) of the fractures 202 and 212 , Other evaluation factors than the formation of the breakpoint took into account the evaluation of the magnitude of the breakage effect compared to the effects of the other factors.

To evaluate the effect that the stitchstrength has on the peel strength of the tear seam, the Tex-90 yarn was compared to the Tex-105 yarn. To evaluate the impact, the weight of the one to produce each other For example, when bonded sections used fabric had peel strength, a 585 dtex fabric was compared to a 700 dtex fabric. To evaluate the effect of coating the fabric used to make the bonded sections on peel strength, coated versus uncoated fabrics were considered. Finally, to evaluate the effect that the embodiments of the break points 202 and 212 on the shear and peel strength of the seam have compared sharp fractures with flattened fractures.

• 1. Spitze Naht gegenüber flache Naht.
• 2. Fadenstärke.
• 3. Gewebebeschichtung.
• 4. Gewebegewicht.

In an attempt at peel strength, it was found that all four factors contribute significantly to the peel strength of the tear seam. In particular, the factors contributed, to varying degrees, to the peel strength, as listed below in the order of the degree of contribution, with the most significant contribution being mentioned first:

• 1. tip seam versus flat seam.
• 2. Thread thickness.
• 3. Fabric coating.
• 4. Tissue weight.

• 1. Fadenstärke.
• 2. Gewebegewicht.
• 3. Gewebebeschichtung.

In the shear strength test, it has been found that three of the four factors contribute significantly to the shear strength of the tear seam. In particular, three major factors contributed to varying degrees of shear strength, as listed below in order of the degree of contribution, the most significant being the first to be cited:

• 1. Thread thickness.
• 2. Tissue weight.
• 3. Fabric coating.

In this series of tests, it should be noted that the stitch shape (pointed towards flat) of the break points 202 and 212 a very small effect on the shear strength of the tear seam 200 respectively. 210 would have.

It has thus been found by the abovementioned tests that the puncture of the fracture, which is of little importance in the determination of the peel strength and in the determination of the shear strength, can be adjusted in such a way that it adapts the peel strength, while at the same time achieving a produced little effect on the shear strength. Since the other factors (thread strength, fabric weight and fabric coating) significantly affect both shear strength and peel strength, none of them can be used to adjust only one of the shear or peel strengths without affecting the other of the two.

Inwardly directed opposite outwardly directed end portions

The 7A and 7B illustrate inward and outward end portions 222 respectively. 232 , Attempts have been made to study the effects of an inwardly directed end portion 222 (please refer 7 ) compared to an outwardly directed end portion 232 on the shear strength of the tear seam 220 respectively. 230 determine. In order to direct the tests to the end sections, the tests were performed on a V-shaped seam with sharp break points 226 and 236 and straight leg sections 224 respectively. 234 carried out. In carrying out these tests, the factors which were evaluated were the suture thickness, the weight of the fabric used to make the interconnected sections, the direction of pull (up to down) and the formation of the end sections 222 and 232 , Other evaluation factors than the formation of the end portion took into account the evaluation of the magnitude of the effect that the formation of the end portion has as compared to the effects of the other factors.

To evaluate the effect that the stitchstrength has on the peel strength of the tear seam, the Tex-70 yarn was compared to the Tex-90 yarn. To evaluate the effect on the peel strength of the weight of fabric used to make the bonded sections, a 470 dtex uncoated fabric was compared to a 700 dtex uncoated fabric. To evaluate the effect that the training of the end section break points 222 and 232 to have the shear and peel effect of the seam, the tear seam became 220 and 230 identical in a 46-stitch pattern, the only difference being in the inward / outward directions of the end portions.

• 1. Fadenstärke.
• 2. Richtung des Endabschnittes.
• 3. Gewebeart.

In the shear strength test, it has been found that three of the four factors contribute significantly to the shear strength of the tear seam. In particular, three major factors contributed to varying degrees of shear strength, as listed below in order of the degree of contribution, the most significant being the first to be cited:

• 1. Thread thickness.
• 2nd direction of the end section.
• 3. Fabric type.

The pulling direction had a very small, insignificant effect on the shear strength of the seam. In this series of experiments, the fact was of particular interest that the inward end sections 232 compared to the seam 220 with the outwardly extending end portions 222 to a seam 230 with higher shear force. It was therefore found that the direction of the end portion could be used as an option in designing or adjusting the tear strength of the tear seam.

In addition, multiple retries for each of the two stitch patterns proved that the inward-facing end portion 222 the variations in shear strength relative to the outwardly directed end portion 232 has decreased. The inward-facing end section 222 thus led to repeatable and more reliable results. In observing the experiments it was found that the outward-facing end sections 232 began to separate at their edges, while the inward-facing end sections 222 at the intersection with the leg sections 224 began to rip. The severing can not be controlled, whereas the tearing can be controlled (eg via the thread thickness). Therefore, the inward end sections provide 222 for the added benefits of controllability.

Number of stitches

The 8A and 8B show the number of stitches for sharp and shallow cracks 246 respectively. 256 , Experiments were performed to determine the effects that the stitch counts have on the shear strength of the tear seam 240 (please refer 8A ) and 250 (please refer 8B ) Has. The tests were performed on a V-shaped seam with both sharp and straight break points 246 respectively. 256 and with straight leg sections 244 respectively. 254 carried out. In all experiments had the tear seam 240 and 250 identical, rolled-up end sections 242 respectively. 252 ,

In performing these tests, the factors evaluated were the number of stitches in the tear seam 240 . 250 limited. All individual stitches were 3 mm long. Each end section 242 . 252 included 7 stitches. Each flattened end section 256 pointed out two stitches, in 8B generally designated "B". In order to change the number of stitches in each pattern, the number of respective stitches in the leg portions became 244 and 254 , generally with "A" or "C", changed. Three patterns were evaluated: a pattern with 36 stitches, a pattern with 44 stitches and a pattern with 54 stitches.

The tests showed that the number of stitches significantly to the shear strength of the tear seam 240 and 250 contributed. In addition, it was again found that the question of whether the tear seam the sharp break point 246 or the flattened break point 256 has a negligible effect on the shear strength of the tear seam. Therefore, it was found that the number of stitches could be used as an option in designing or adjusting the shear strength of the tear seam.

Rolled end sections

The 9A - 9C show rolled-up end sections 262 . 272 respectively. 282 for different stitch types. Experiments were performed to evaluate the effects of rolled-up end sections 262 on the shear strength and peel strength of the tear seam 260 (please refer 9A ), the effects of rolled-up end sections 272 on the shear strength and peel strength of the tear seam 270 (please refer 9B ) as well as the effects of rolled-up end sections 282 on the shear strength and peel strength of the tear seam 280 (please refer 9C ). The suture had straight leg sections in these trials 264 . 274 and 284 on. In carrying out these tests, the factors evaluated were the bobbin thread, the stitch thread thickness, the execution of the break points 266 . 276 . 286 and the question of whether the seam has two rows of self-releasing seam 290 had adjacent to the breakages.

To evaluate the effect that bobbin thread has on the shear and peel strength of the tear seam, a Tex-138 thread was compared to a Tex-210 thread. To evaluate the effect that the stitchstrength has on the shear and peel strength of the tear seam, a Tex-90 thread was compared to a Text-106 thread. To evaluate the effect that the self-releasing suture 290 on the shear and peel strength compared to the pointed and flattened break points 266 respectively. 276 the self-releasing seam became the seam 280 added.

In the shear strength test, it was found that the stitch strength was significant to the shear strength of the seam 260 . 270 and 280 contributed. The bobbin thread also contributed significantly to the shear strength of the seam 260 . 270 and 280 at, but not to the extent of stitch thread strength. The self-releasing seam 290 provided some, albeit minimal, contribution to the shear strength of the seam 260 . 270 and 280 , This minimal contribution is further reduced as the purpose of the self-releasing seam 290 would consist of absorbing initial forces in the stripping direction. Finally had the sharp break point 266 opposite the flat break point 276 no discernible effect on the shear strength of the seam 260 and 270 ,

In the attempt to peel strength was found that the stitch thread strength essential to the peel strength of the seam 260 . 270 and 280 contributed. The inclusion of the pointed break point 266 compared to the flattened break point 276 also contributed significantly to the peel strength of the seam 260 . 270 and 280 at (the sharp break point markedly reduced peel strength), but not to the extent of stitch thread strength. The self-releasing seam 290 and the bobbin thread strength contributed only minimally to the peel strength of the seam 260 . 270 and 280 at.

From the above was therefore to recognize that in the in the 9A and 9B illustrated seam 260 and 270 The stitch strength and bobbin thread strength contributed significantly to the shear strength of the seam. The tip compared to the flat version of the break points 266 and 276 had little influence on the shear strength of the seam 260 and 270 , Furthermore, it was evident from the above that the stitch thread strength contributed significantly to the peel strength of the seam. The pointed version of the break points 266 and 276 compared to the flat design also contributed significantly to the peel strength of the seam 260 and 270 at. The thickness of the lower thread had little influence on the peel strength of the seam 260 and 270 ,

Therefore, the bobbin thread was wearing with regard to the seam 260 and 270 with the in the 9A and 9B shown, rounded end sections significantly and clearly to the shear strength of the seam at, and the inclusion of the tips against flattened fractures 266 respectively. 276 contributed significantly and clearly to the peel strength of the seam. Advantageously and according to the invention, the use of a lower thread, which is stronger than the stitch thread, ensures that the stitch thread first tears at the break point in a peel-off case. As a result, the lower thread has no effective influence on the peel strength of the seam, whereby the lower thread can be made to provide a desired shear strength.

Finally, the rounded end sections 262 and 272 the seam 260 respectively. 270 of the 9A and 9B contribute to that with the inward end sections 222 of the 7A to remedy the observed case. The inward end sections 222 started at the interface with the leg sections 224 because the sharp vertex of the angle effectively concentrated the shear forces on these interfaces and created break points at those locations. The rounded end sections 262 and 272 the embodiments of the 9A and 9B distribute the shear forces and thus avoid focusing this shear force and resulting tearing. Consequently, the rounded end portions provide 262 and 272 for the further advantage of improved controllability of the shear strength of the seam.

Thigh sections-Different V-shapes

Experiments were performed to determine the effects of various shapes of the leg portions of the tear seam. With all other factors remaining the same, rounded end sections combined with pointed break points provide the highest ratio of shear strength to peel strength ("Shear / Peel Ratio"). With this recognition, the formation of the leg portions is the remaining major factor that can be adjusted to provide a desired (eg, greatest possible) shear deduction ratio. Different designs of the leg sections were investigated. In order to maximize the shear peel ratio for each of the different shapes tested, the seam included rounded end portions and a sharp break point.

Examples of the different types of stitches studied are in 10 shown. In each embodiment, the bobbin thread was a Tex-138, the stitching thread was a Tex-105 and the stitch was 3 mm. The seam joined identical material sections with each other. 10 illustrates the shape of the tested tear seam design, the number of stitches used to form the seam and the resulting shear / peel ratio.

The seam 300 essentially represents the stitch execution with straight leg sections, which in 8th is illustrated. The seam 300 comprised 53 stitches and produced a shearing / peeling ratio of 6.96.

The seam 302 extends or expands the curled end portions downwardly and correspondingly shortens the length of the straight leg portions. The leg portions thus have a total shape in which the leg portions are convexly curved away from each other. The seam 302 comprised 53 stitches and produced reduced shear strength and increased peel strength compared to the seam 300 with a corresponding reduction in the shear / peel ratio to 5.34.

The seam 304 Prolongs or expands the rolled end portions continue down and further shortened according to the length of the straight leg sections. The leg portions thus have a total shape in which the leg portions are convexly curved away from each other. The seam 304 comprised 53 stitches and produced further reduced shear strength and further increased peel strength compared to the seam 302 with a corresponding reduction in the shear / peel ratio to 4.60.

The seam 306 has one to the seam 300 similar or identical seam, wherein a other similar, scaled down seam is used in this. The seam 306 comprised 98 stitches and thus produced a greatly increased shear strength compared to the seam 304 , The peel strength, which was increased due to the additional seam, did not increase in the same proportion as the shear strength. The seam 306 led to an increase in the Scher- / Abziehverhältnisses to 7.37.

The seam 308 takes over the nested seam formation and connects the two seams with a rounded end section. The seam comprised 83 stitches and could only slightly increase the shear strength compared to the seam 306 produce. The peel strength of the seam 308 also decreased in comparison to the suture 306 with a larger ratio than that of the shear strength. The seam 308 led to an increase in the Shear / Deduction Ratio to 7.64 despite the lower number of Stings.

The seam 310 is like the seam 308 , except for the fact that the seam 310 has a narrower overall width and a greater thickness. The seam 310 covered 72 stitches and produced a substantial reduction in shear strength compared to the seam 308 , The peel strength of the seam 310 took in compared to the suture 308 but the reduction was not so significant. The seam 310 led to a reduction of the cut-off ratio to 6.82.

The seam 312 is like the seam 310 , except for the fact that the seam 312 has a larger overall width and the same thickness. The seam 312 comprised 84 stitches and produced a significant increase in shear strength compared to the seam 310 , The seam 312 however, brought almost no reduction in peel strength compared to the seam 310 , The seam 312 led to an increase in the Scher- / Abziehverhältnisses to 7.99.

Realization of examples

The 11 and 12 represent the realization of examples of the tear seam 100 In the realization of the example of the 11 and 12 becomes the seam 100 used to sections of an adaptive tether 400 for adapting the shape of an airbag 402 depending on occupant conditions in a vehicle 404 to connect with each other. The airbag 402 consists of a section of an airbag module 432 that is in a dashboard of the vehicle 404 is appropriate.

In the 11 and 12 is the adaptive tether 400 a three-piece tether that has an anchoring strap 412 a form belt 414 and a release strap 416 having. The anchoring belt 412 corresponds to the first segment 150 of the 2 and 3 , The form belt 414 corresponds to the second segment 152 of the 2 and 3 , The release strap 414 corresponds to the third segment 154 of the 2 and 3 ,

The anchoring belt 412 has a first, on the vehicle 12 at the point 420 anchored end section on. The form belt 414 has a first, at an upper portion 424 a front line 422 of the airbag 404 attached end portion. The release strap 416 has a first, at a lower section 426 the front line 422 of the airbag 404 attached end portion.

In an unactivated state of the adaptive tether 400 are the anchor belt 412 , the shaping belt 414 and the release strap 416 through the tear seam 100 connected with each other. In this exemplary embodiment, the tear seam is 100 capable of connecting the anchoring strap 412 and the shaping and release belt 414 and 416 depending on the conditions in the vehicle 404 to solve if the airbag 402 unfolded.

One through the shaping belt 414 applied tension brings a shearing force on the tear seam 100 on. One through the release strap 416 applied tension brings a peel force on the tear seam. The seam 100 thus has a high shear strength as a function of the form of the belt 414 applied tension and a relatively low peel strength as a function of the release belt 416 applied voltage on.

When an event occurs, the inflation of the airbag 402 requires the adaptive tether responds 400 for controlling the inflation and deployment of the airbag to vehicle conditions, occupant conditions or both. According to the embodiment of the 11 and 12 This control is passively by the technical design or execution of the airbag 402 and the adaptive tether 400 , The airbag 402 For example, it may be designed to be responsive to the size or position of the vehicle occupant 406 responding.

Referring to 11 is the inmate 406 relatively close to the dashboard 430 positioned and thus relatively close to the airbag module 432 , This may be the case, for example, with a relatively small occupant, such as a child or a small female occupant. For comparison, a large inmate 406 ' , such as As an average or large, male adult, shown in phantom. The skilled person will realize that the smaller occupant 406 the vehicle seat 408 in a position in front of the seat 408 of the larger occupant 406 ' can adjust.

As in 11 represented, detected in the case of a further positioned occupant 406 the middle / lower section 426 the front line 422 of the airbag 402 the inmates during the unfolding. The occupant positioned further forward 406 prevents, as shown, that the middle / lower section 426 fully unfolds and thereby prevents the deployment belt 416 is tense. As a result, the release strap brings 416 no significant tension or force on the tear seam 100 on.

On the other hand, as in 11 shown, it comes in the case of a further positioned occupant 406 to no detection of the occupant by the upper section 424 the front line 422 of the airbag 402 during the unfolding. The occupant positioned further forward 406 prevents the upper section 424 not at the full unfolding, and consequently the shaping belt 414 and the anchor belt 412 through the unfolding front line 422 of the airbag 402 curious; excited. As a result, the tension in the molding belt becomes 414 and in the anchor belt 412 on the tear seam 100 applied, which connects the two straps.

Because the tear seam 100 As described above, has a relatively high shear strength, ruptures the tear seam in the case of the occupant positioned further forward 11 depending on the shape of the belt 414 not applied voltage. With the help of the forming belt 104 will the shape of in 11 retained airbags. The person skilled in the art will recognize that the shaping belt 414 the upper section 424 the front line 422 in a position from the head of the occupant positioned further forward 406 keeps away.

Referring to 12 is the inmate 406 from the dashboard 430 removed and thus relatively far away from the airbag module 432 positioned. This may for example be the case with a relatively large occupant, such as an adult male occupant. For comparison, a small inmate 406 ' , like a child or a small female inmate, shown in dashed lines in a forward sitting position. The skilled person will realize that the larger occupant 406 the vehicle seat 408 in a position behind the seat 408 ' the smaller inmate 406 ' can adjust.

How out 12 apparent hinders in the case of a passenger positioned further back 406 this the development of the middle / lower section 426 the front line 422 of the airbag 402 Not. The middle / lower section 426 can unfold freely in a fully unfolded position. Consequently, the release strap 416 under the power of the unfolding front line 422 cocked and the release belt 416 brings a significant tension or force on the tear seam 100 on.

Because the tear seam 100 as described above, has a relatively low peel strength, ruptures the tear seam in the case of the occupant positioned further back 12 depending on the release belt 416 applied voltage. This will be the connection between the anchor belt 412 and the shaping belt 414 solved. As a result, the shaping belt holds 414 not the shape of the airbag 402 upright and the airbag can inflate to the fully deployed position as in 12 shown.

In view of the above description, those skilled in the art will recognize that the tear seam 100 of the present invention, the adaptive tether 400 allows the deployment of the airbag 402 in the case of a passenger positioned further forward or to limit, and in the case of an occupant positioned further back to allow full deployment. The skilled person will further recognize that by the tear seam 100 enabled, adaptive function of the tether 400 is not limited to a front / rear occupant position per se. For example, the adaptive tether could 400 act in a similar way to the deployment of the airbag 402 to shape or limit when a child seat on the vehicle seat 408 is appropriate. In addition, the adaptive tether could 400 work similarly to the deployment of the airbag 402 in the case of a particularly large occupant, regardless of the front / rear position of the seat 408 to shape or limit. Furthermore, the adaptive tether could 400 work similarly to the deployment of the airbag 402 to shape or limit, if an occupant is not positioned in a normal sitting position when he is z. B. in a bent over or forward leaned position, regardless of the front / rear position of the seat 408 and regardless of the size of the occupant.

From the foregoing description of the invention, those skilled in the art will perceive improvements, changes and modifications. While the example of 11 and 12 FIG. 4 illustrates an insert in which tethers have been joined together by the tear stitching of the present invention, one skilled in the art will recognize that one or more of the tether straps could be removed and the portion of the airbag with which the tethers removed were fastened directly by the tear stitching could be. Moreover, while the example of the 11 and 12 illustrates an insert in which the tear seam is used to adaptively shape the airbag, recognize an insert in which the tear seam is used to adaptively actuate an actuator, such as an airbag. B. a vent.

It will be understood by those skilled in the art that the particular features of the described tear stitching, particularly the formation of the break point as a sharp break compared to a flat break, the formation of the end portions as inwardly directed end portions towards outwardly directed end portions, the number of stitches, the Rolling the end portions, the formation of the leg portions, and the formation of different V-shapes, are arbitrarily combined with each other to adapt the tear seam to respective conditions of the airbag or the vehicle interior or the triggering situation.

Further improvements, changes and modifications of this kind within the skill of the art are intended to be covered by the appended claims.

Claims (11)

Tear seam for joining sections of an inflatable vehicle occupant protection device, comprising: a first end portion; a second end portion; and a central portion extending between the end portions, the middle portion having first and second leg portions converging at an angle and crossing a breakpoint; wherein the first end portion extends from the first leg portion along a path that deviates from the path of the first leg portion; wherein the second end portion extends from the second leg portion along a path that deviates from the path of the second leg portion; wherein the tear seam has a comparatively high tear resistance as a function of the tensile forces applied to the interconnected portions, which act on the end portions of the tear seam; wherein the tear seam has a comparatively low tear strength as a function of the tensile forces applied to the interconnected sections, which act on the break point of the tear seam. A tear seam according to claim 1, wherein the leg portions of the central portion are V-shaped, and / or preferably wherein the first and second end portions are rolled inwardly with respect to the V-shape of the central portion and in the direction of the breakage, and / or preferably wherein the first and second end portions have a rolled-up shape, and wherein preferably the rolled-up shape of the first and second end portions is selected such that the ends of the first and second portions are hidden from tension forces applied to the interconnected portions, which act on the end portions of the tear stitching. A tear seam according to claim 1 or 2, wherein the leg portions are convexly curved away from each other. A tear seam according to claim 2, wherein the end portions are rolled inwardly more than ninety degrees from their respective interfaces to the central portion, and / or wherein the end portions are inwardly curled more than one hundred and eighty degrees inwardly from their respective interfaces to the central portion, and / or the end portions are rolled inwardly more than two hundred and seventy degrees from their respective interfaces to the central portion. A tear seam according to at least one of the preceding claims 1-4, wherein the break has a single stitch, and / or wherein the leg portions extend away from each other and away from the break point. A tear seam according to at least one of the preceding claims 1-4, wherein the break has a plurality of stitches arranged in a line and extending transversely of the leg portions, preferably wherein the break has at most two stitches, and / or preferably the leg portions away from each other and away from the breakpoint. A tear seam according to at least one of the preceding claims 1-6, wherein the portions of the protector include first and second portions of the protector overlaying each other, the tear stitch passing through and interconnecting the first and second portions, the first portion being one a first material segment and the second portion having a second material segment extending away from the end portions of the tear seam in a first direction and a third material segment extending away from the break point of the tear seam in a second direction; wherein the portions of the protector and the tear seam are constructed and arranged such that a tension applied to the first and second segments generates a shear force directed toward the end portions, the tear seam thus having a comparatively high tear strength; wherein the portions of the protector and the tear stitching are constructed and arranged such that the tension applied to the first and third segments produces a peel force exerted on the Break point is addressed, the tear seam thus has a relatively low tear strength. A tear seam according to at least one of the preceding claims 1-7, further comprising a self-releasing portion adapted to be subjected to initial tension forces acting on the interconnected portions, preferably wherein the tear seam is configured such that tearing of the self-releasing portion occurs in response to an initial increase in tension between the interconnected portions, the self-releasing portion receiving the initial rise and the remainder of the tear seam being subject to tension forces after the initial rise decreases; thus is able to withstand the tension forces without tearing, and / or preferably wherein the self-releasing portion is disposed adjacent to the fracture site, wherein the tear seam is configured such that the self-releasing portion is subjected to tension between the portions and tears depending on the tension forces before the tension forces act on the fracture site, and / or wherein preferably the self-releasing portion has at least one V-shaped seam portion inserted around the break point. The tear seam according to at least one of the preceding claims 1-8, wherein the first and second end portions have a rolled-up shape, wherein preferably the rolled-up shape of the first and second end portions is selected such that the ends of the first and second end portions project toward the interconnected portions are hidden applied tension forces acting on the end portions of the tear seam. An inflatable vehicle occupant protection device that can be brought from an uninflated state to an inflated state; and at least one tear seam for joining portions of the protective device together, wherein the tear seam is formed according to at least one of the preceding claims 1-9. Vehicle safety system with an inflatable vehicle occupant protection device according to claim 10 and actuator assembly, in particular with a gas generator, for inflating the occupant protection device, wherein preferably an electrical activation unit is provided which is signal-connected to the actuator assembly such that an electrical trigger pulse is transferable to the actuator assembly, and wherein preferably further at least one sensor for detecting vehicle movement data is connected to the activation unit, and the activation unit is configured to transmit the electrical release pulse in dependence on the measured vehicle movement data to the actuator assembly, in particular the gas generator.

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