CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119 to following German Patent application no. 10 2016 114 843.1, filed Aug. 10, 2016, the contents of which are incorporated herein by reference thereto.

TECHNICAL FIELD

The invention relates to an arrangement comprising a visible seam and a lighting apparatus for illuminating the visible seam. The invention additionally relates to the use of this arrangement and a method for production thereof.

BACKGROUND

Visible seams are used today in a wide range of ways in the processing of sheet material parts, such as textile material parts, leather material parts, imitation leather material parts, plastic material parts, etc.

The object of the invention is to improve the appearance of such visible seams and to extend the possibilities for use thereof.

SUMMARY

An arrangement including a visible seam and a lighting apparatus, wherein the visible seam comprises an upper thread and a lower thread, wherein the upper thread comprises first thread portions extending along an upper side of a sheet material part and second thread portions, which run through stitch holes through the sheet material part and which are each interlaced with the lower thread at an underside of the sheet material part beneath each stitch hole, wherein the lighting apparatus comprises one or more light sources and is adapted to emit light at a plurality of light emission locations beneath the underside of the sheet material part, wherein the lighting apparatus is adapted to couple the light emitted at the plurality of light emission locations into the second thread portions of the upper thread beneath the stitch holes, the light emitted at the plurality of light emission locations propagates along the second thread portions of the upper thread and, starting from the second thread portions propagates partially along adjacent first thread portions of the upper thread and is diffusely emitted in part by the first thread portions, wherein the upper thread comprises a plurality of multi-filament yarns wherein each one of the plurality of multi-filament yarns include filaments twisted together.

An arrangement comprising a visible seam and a lighting apparatus, wherein the visible seam includes an upper thread and a lower thread, wherein the upper thread comprises first thread portions extending along an upper side of a sheet material part and second thread portions, which run through stitch holes through the sheet material part and which are each interlaced with the lower thread at an underside of the sheet material part beneath each stitch hole, wherein the lighting apparatus comprises one or more light sources and is adapted to emit light at a plurality of light emission locations beneath the underside of the sheet material part, wherein the lighting apparatus is adapted to couple the light emitted at the plurality of light emission locations into the second thread portions of the upper thread beneath the stitch holes, the light emitted at the plurality of light emission locations propagates along the second thread portions of the upper thread and, starting from the second thread portions propagates partially along adjacent first thread portions of the upper thread and is diffusely emitted in part by the first thread portions, wherein the upper thread and the lower thread each comprise a plurality of multi-filament yarns wherein each one of the plurality of multi-filament yarns include filaments twisted together.

An arrangement comprising a visible seam and a lighting apparatus, wherein the visible seam includes an upper thread and a lower thread, wherein the upper thread comprises first thread portions extending along an upper side of a sheet material part and second thread portions, which run through stitch holes through the sheet material part and which are each interlaced with the lower thread at an underside of the sheet material part beneath each stitch hole, wherein the lighting apparatus comprises one or more light sources and is adapted to emit light at a plurality of light emission locations beneath the underside of the sheet material part, wherein the lighting apparatus is adapted to couple the light emitted at the plurality of light emission locations into the second thread portions of the upper thread beneath the stitch holes, the light emitted at the plurality of light emission locations propagates along the second thread portions of the upper thread and, starting from the second thread portions propagates partially along adjacent first thread portions of the upper thread and is diffusely emitted in part by the first thread portions, wherein the upper thread has a smaller cross-section than the lower thread.

A method for producing an arrangement including a visible seam and a lighting apparatus, wherein the visible seam comprises an upper thread and a lower thread, wherein the upper thread comprises first thread portions extending along an upper side of a sheet material part and second thread portions, which run through stitch holes through the sheet material part and which are each interlaced with the lower thread at an underside of the sheet partial part beneath each stitch hole, wherein the lighting apparatus comprises one or more light source and is adapted to emit light at a plurality of light emission locations beneath the underside of the sheet material part, wherein the lighting apparatus is adapted to couple the light emitted at the plurality of light emission locations into the second thread portions of the upper thread beneath the stitch holes, the light emitted at the plurality of light emission locations propagates along the second thread portions of the upper thread and, starting from the second thread portions propagates partially along adjacent first thread portions of the upper thread and is diffusely emitted in part by the first thread portions, wherein the upper thread comprises a plurality of multi-filament yarns wherein each one of the plurality of multi-filament yarns include filaments twisted together, including the following steps: producing the visible seam, wherein the upper thread is pulled from the upper side of the sheet material part through the stitch holes formed by using a sewing needle, and wherein a cross-sectional area of the sewing needle is smaller than twice a cross-sectional area of the upper thread, providing the light apparatus having the plurality of light emission locations beneath the underside of the sheet material part.

A visible seam in the present application is understood to mean a seam that is at least partially visible on the end product. The visible seam can be just a stitching, or a combination of a stitching and a functional or connecting seam. The visible seam can thus be used not only as a stitching element, but also to connect a plurality of sheet material parts.

The arrangement according to the invention comprises a visible seam and a lighting apparatus. The visible seam is introduced into a sheet material and has an upper thread on the upper side of the sheet material part and a lower thread on the underside of the sheet material part. Any two-dimensional or three-dimensionally-shaped sheet material that can be handled or processed by sewing can be used as sheet material part. Such sheet materials can be, by way of example, a covering of a panel in a vehicle interior (door, fittings, roof lining, etc.) or a seat covering of a vehicle seat. The sheet material part can be, for example, a textile material (for example a fabric), leather, imitation leather, or a plastic film, etc.

The upper thread has first thread portions running along the upper side of the sheet material part. The first thread portions are adjoined by second thread portions of the upper thread, which run through stitch holes in the sheet material part from the upper side to the underside, or vice versa. Two second thread portions of the upper thread extend through each stitch hole. Beneath the stitch hole, the two second thread portions are connected to or interwoven with the lower thread of the visible seam.

The directly adjacent stitch holes of the visible seam are arranged at a distance from one another preferably ranging from 2 to 10 mm and in particular ranging from 4 to 6 mm. The length of the first thread portion of the upper thread corresponds to the distance between directly adjacent stitch holes.

The arrangement additionally comprises a lighting apparatus which has one or more light sources. The lighting apparatus is adapted to emit light at a plurality of light emission locations beneath the underside of the sheet material part. The light emission locations are arranged in at least one row on the underside in the direction of the visible seam. The light emission locations do not have to be arranged in a plane running at right angles to the sheet material part along the visible seam. The light emission locations can also be arranged offset to this plane in one or more rows beneath the underside of the sheet material. In a preferred exemplary embodiment, each light emission location is formed by a separate light source of the lighting apparatus, for example a semiconductor light source, such as a light-emitting diode.

The light emitted at the light emission locations is directed directly—or indirectly after one or more reflections—towards the second thread portions beneath each stitch hole and is coupled there into the second thread portions of the upper thread. The light propagates along the fibers or filaments of the second thread portions through the stitch hole to the upper side of the sheet material. At the upper side, the light is emitted partially from the subsequent first thread portion of the upper thread and is conducted along the first thread portion partially by reflections at the fibers or filaments of the upper thread. Some of the light exits at each location along the first thread portions. The amount of light propagating along a first thread portion thus decreases with increasing distance from a stitch hole. Since each first thread portion connects two stitch holes, a substantially constant brightness of the emitted light is nevertheless achieved along a first thread portion. This is because some of the light that is directed along the upper thread by the second thread portions of adjacent stitch holes is still present in the middle between two stitch holes. An emission of light that is relatively constant to an observer can thus be achieved along the first thread portions.

It is preferred if the distance between two directly adjacent light emission locations in the direction of the visible seam is different from the distance between directly adjacent stitch holes of the visible seam. It is thus possible to use a smaller number of lighting means or light-emitting diodes or light emission locations to achieve a constant illumination of the visible seam.

The second thread portions bear tightly against the sheet material within the stitch holes. A direct, straight emission of light through gaps between the two second thread portions and the peripheral wall of the sheet material part delimiting a stitch hole is substantially completely avoided. This results in the effect that merely the upper thread illuminates the visible seam. Light does not run past the upper thread upwardly through the stitch holes.

The direct emission of light through the stitch holes is also reduced or avoided by the lower thread, which extends beneath the stitch holes. In a preferred exemplary embodiment the cross-section or the thickness of the lower thread is greater than that of the upper thread. The lower thread can therefore cover the stitch hole, at least for the most part, at the underside of the sheet material.

The lower thread is constructed in such a way that the fibers or filaments of the lower thread primarily extend at right angles to the orientation of the stitch holes. The main direction of orientation of the fibers or filaments is therefore in the direction of extension of the lower thread and not transversely thereto. Light that contacts the lower thread from the light emission locations is reflected there. A greater light emission intensity in the region of the stitch holes at the upper side of the sheet material is thus also avoided.

In a preferred embodiment, the upper thread and/or the lower thread are/is embodied as a multi-filament yarn. Here, the twist of the upper thread embodied as a multi-filament yarn can be less than the twist of the lower thread embodied as a multi-filament yarn.

In order to achieve a light perception that is as constant as possible, it is advantageous if the twist of the upper thread embodied as a multi-filament yarn is as small as possible. For a suitable sewing behavior and a uniform seam pattern, a minimum twist is required so that the filaments are sufficiently connected to one another. In one exemplary embodiment, the twist of the upper thread can lie in a range of 20-400 twists per meter.

For the lower thread, the same principles apply as for the upper thread. However, in the case of the lower thread, greater attention can be placed on the sewing behavior, since the lower thread must not conduct any light along its extent. The twist of the lower thread embodied as a multi-filament yarn can preferably range from 20-400 twists per meter and can also be up to 1000 twists per meter.

The upper thread and/or the lower thread can be embodied as twine. The twine can contain a plurality of twisted multi-filament yarns. The number of steps in which in each case a plurality of filaments or twisted multi-filament yarns are twisted with one another can be selected here suitably. At the least, two such steps are provided in order to form the twine. In one exemplary embodiment, a plurality of filaments are twisted in the first step to form in each case a multi-filament yarn. In a second step, these multi-filament yarns are in turn twisted with one another. The twisting in the first step by way of example can be embodied as an S-twist, and the twisting in the second step can be embodied as a Z-twist, or vice versa. It is also possible to select the direction of twisting in both twisting steps to be in the same direction.

In the case of twine, a twisting of 20-400 twists per meter can be selected in each step. It is advantageous if, with twisting in the same direction in both steps, the sum of the twists in the two steps is at least 20 twists per meter and for the upper thread does not exceed 400 twists per meter and for the lower thread does not exceed 400 or up to 1000 twists per meter. With twisting directions in opposite directions in the first step and in the second step, it is preferred if the difference from the twist of the first step minus the twist of the second step ranges from 20-400 twists per meter for the upper thread and ranges from 20-400 twists per meter and at most up to 1000 twists per meter for the lower thread.

An auxiliary, such as wax, oil, etc., can be added to the upper thread and/or the lower thread in order to improve the sewing behavior. It is also possible to add this auxiliary just to one or more yarns of a twine.

The twist of the upper thread and/or lower thread embodied as a multi-filament yarn is less than that which would be used for a conventional sewing yarn in order to attain a good thread cohesion and a good sewability. The smaller twist can improve the desired propagation of part of the coupled-in light along the upper thread.

It is advantageous if the upper thread and/or lower thread is colored. In a preferred exemplary embodiment, the upper thread or the lower thread is white or appears to be white, since substantially all light wavelengths of visible light will be reflected. Other colors, such as blue, red, etc., can also be used. The upper thread and/or lower thread can be colored by addition of pigments.

The upper thread preferably has a smaller mass per meter (tex) than the lower thread.

In a preferred embodiment, the first thread portions of the upper thread form a first thread layer. A second thread layer can be applied to this first thread layer by means of at least one additional thread, preferably by stitching. The orientation of the thread portions of the at least one additional thread in the second thread layer can be at right angles and/or obliquely and/or parallel to the first thread portions of the upper thread. The thread portions of the at least one additional thread are preferably arranged parallel to one another in the second thread layer. The threads of the second thread layer by way of example can form a letter, a number, a symbol, a logo or any other symbol to be illuminated. Backlit elements can thus be created in the sheet material part.

In a preferred embodiment, the sheet material part is sewn to a further sheet material part by means of a connecting seam, adjacently to the visible seam. Here, both sheet material parts can have a visible seam adjacently to the connecting seam. The sheet material parts are held together by the connecting seam. The at least one visible seam does not have a fixing function for holding together the two sheet material parts.

It is advantageous if at least one shielding means is provided at or adjacently to the connecting seam. By means of the at least one shielding means, the passage of light through the connecting seam or through the contact region between the two sheet material parts from the underside to the upper side can be at least reduced and in the ideal case completely prevented. Here, the at least one shielding means is at least partially impermeable for the emitted light wavelength. The shielding means can be formed by a non-transparent sheet, by a non-transparent close-meshed textile or lattice structure, or the like.

In one exemplary embodiment, the shielding means is formed by a seam tape or comprises a seam tape. The connecting seam by way of example can comprise two seam tapes, one on each of the two sheet material parts.

In a further preferred exemplary embodiment at least one supporting body is provided. In one exemplary embodiment, a supporting body is provided in the region of each visible seam. The supporting body is designed in each case to support an associated sheet material part at the underside. The supporting body by way of example can be formed from a resilient material. The supporting body is preferably produced from a material that is transparent for the emitted light wavelength.

It is advantageous if the shielding means is arranged or formed on the supporting body. By way of example, no or only a few structures or areas permeable to light can be provided or formed on the supporting body adjacently to the connecting seam. Corresponding microstructures or reflection areas can be provided in the supporting body, at which microstructures or reflection areas the impinging light is reflected and directed away from the connecting seam.

The lighting apparatus can comprise at least one delimiting face for the arrangement of the light emission locations. By way of example, it is advantageous if three delimiting faces adjoining one another form a channel delimited on three sides, for example a U-shaped or groove-shaped channel, which for example can be arranged beneath the associated visible seam. The cross-sectional shape of the channel can be selected arbitrarily and can also vary along the extent of the channel. The at least one delimiting face is preferably diffusely reflective and by way of example can be formed from a face with appropriate roughness, preferably a white face.

Since the lighting apparatus is disposed beneath the underside of the sheet material part, it is covered by the sheet material part in the use position or installed position and is not visible to the observer.

As explained, the above-described arrangement can be used advantageously in an interior of a vehicle, in particular a motor vehicle, aircraft, rail vehicle or watercraft. The sheet material part can therefore be used for example to provide a covering on the roof lining, in a door, or on the dashboard. The sheet material part can also be part of a seat covering.

When producing the arrangement, a visible seam is produced in the sheet material part with the aid of a sewing needle. The upper thread is drawn through a stitch hole by means of the sewing needle. The stitch hole is formed in the sheet material by the sewing needle. The needle cross-section is selected in such a way that a close fit of the two second thread portions within the stitch hole with the sheet material part, substantially without gaps, is produced by the resilient properties of the upper thread and the sheet material. The needle cross-section is in particular selected to be as small as possible. The lighting apparatus with the light emission locations is arranged beneath the underside of the sheet material. The light emission locations are preferably arranged at a distance from one another along the visible seam.

The distance between the light emission locations or the light sources and the lower thread is between 0 mm and 50 mm. With use of light-emitting diodes which are arranged at the light emission locations, the spacing is preferably 5-15 mm.

The cross-section of the sewing needle in the case of the method can be selected to be all the smaller, the lower is the resilience of the sheet material part.

Advantageous embodiments of the invention will become clear from the dependent claims, the description, and the drawings.

