Patent Description:
In production of textile products, it is desirable that the products be formed with edges that are not likely to fray or otherwise deteriorate with use, and so that the edges remain attractive during use. Some products are folded at their edges to form hems, which are sewn closed to hide the cut or ragged edge of the product. Other products are instead provided with overedge stitches along the perimeter. For increased durability and to allow for variations in material or colouring, it is also known to apply a binding tape to the edge of the textile product, known in the art as "edge binding". The binding tape is a long strip of fabric, which is folded and typically sewn onto the edge.

Edge binding of textile products may be performed on a sewing machine by manual labour. The general consensus on edge binding is that a high throughput and quality is achieved by applying the binding tape to extend continuously around the entire perimeter of the textile product. To achieve such a continuous edge binding, the textile product is conventionally manufactured with rounded corners. An example of a sewing machine for edge binding by manual operation is disclosed in <CIT>, in which the sewing machine is configured to automatically finish the textile product when the binding tape has been attached along the entire perimeter of the textile product, by folding the trailing end of the binding tape and attaching it to the leading end of the binding tape.

To reduce costs and achieve a more consistent quality of the finished textile products, it is desirable to automate production. <CIT> discloses a representative example of such automated production, in which the textile product is rotated on a working table while the binding tape is applied by an edge binding device comprising a stationary sewing machine and a tape positioning mechanism. It is realized that the size of the working table will scale with the size of the textile product, making it difficult to adapt the production equipment to textile products of different sizes and/or types. The need to rotate the textile product may also limit production rate and increase the complexity of the production equipment.

The prior art also comprises <CIT> which discloses a rug sewing apparatus that is operable to trim the edges of a work piece, for example into one or more square corners, apply a binding tape to the edges, stitch the binding tape to the work piece, remove any excess binding tape along the one or more corners of the work piece, and seal the corners. The latter steps require high-accuracy positioning of the work piece in relation to the rug sewing machine, which increases the required complexity of the production equipment and may be difficult to achieve at high production rates.

It is an objective of the present disclosure to at least partly overcome one or more limitations of the prior art.

A further objective is to increase the production rate of textile products with edge binding.

A yet further objective is to facilitate automated edge binding of textile products.

Another objective is to achieve a high quality finish of the resulting textile products.

One or more of these objectives, as well as further objectives that may appear from the description below, are at least partly achieved by an apparatus, a method, a computer-readable medium and a textile product in accordance with the independent claims, embodiments being defined by the dependent claims.

A first aspect is an apparatus for edge binding a textile work product that has a perimeter comprising first and second edges that meet at a corner at approximately right angles, a binding tape being folded around and attached to the second edge so that an end portion of the binding tape projects beyond the corner in a direction of the second edge. The apparatus comprises a corner finishing device and a conveyor for engagement with the textile work product, and a control device operatively connected to the conveyor and the corner finishing device. The control device is configured to: operate at least one of the conveyor and the corner finishing device to arrange the textile work product with the corner in alignment with the corner finishing device; and operate the corner finishing device to apply a heat seal to the end portion at the corner and cut the end portion at the heat seal to close the binding tape at the corner. The corner finishing device comprises a heat sealing unit which is operable to form a slot with a height that is smaller than a thickness of the binding tape on the second edge, and the control device is configured to, before operating the corner finishing device to apply the heat seal, operate at least one of the conveyor and the corner finishing device to arrange the end portion to extend through the heat sealing unit, operate the heat sealing unit to form the slot with the end portion extending through the slot, and operate the corner finishing device to pull the end portion through the slot in a first direction to thereby drive the corner towards, and optionally into contact with, the slot.

In some embodiments, the control device comprises a software-controlled processor which is connected, via an output interface on the control device, to the conveyor and the corner finishing device and is configured to generate control signals for controlling the operation of the conveyor and the corner finishing device.

In some embodiments, the corner finishing device comprises a gripping unit for engaging the end portion.

In some embodiments, the control device is configured to operate, when the gripping unit is engaged with the end portion, at least one of the gripping unit and the heat sealing unit to pull the end portion in the first direction.

In some embodiments, the corner finishing device comprises a cutting unit integrated with the heat sealing unit, and the control device is configured to operate the corner finishing device to concurrently apply the heat seal by the heat sealing unit and to cut the end portion by the cutting unit.

In some embodiments, the corner finishing device comprises first and second opposing blocks that define a cutting element and a stop for the cutting element, respectively, the first and second blocks being arranged for mutual movement, and the control device is further configured to operate an actuator to mutually move the first and second blocks to form the slot between the cutting element and the stop.

In some embodiments, the cutting element and the stop are arranged to extend in a second direction at right angles to the first direction, and the control device is configured to operate at least one of the conveyor and the corner finishing device to arrange the textile work product with the second edge substantially parallel to the first direction and the first edge substantially extending along the cutting element and the stop in the second direction.

In some embodiments, the first and second blocks comprise opposing surface portions that collectively define a heat sealing region between the first and second blocks, said first and second blocks being arranged with the opposing surface portions jointly defining a tapered space when the first and second blocks have been moved to form the slot between the cutting element and the stop, and the corner is received in the tapered space when the corner is driven towards the slot.

In some embodiments, the cutting element and the stop are located in or adjacent to the heat sealing region defined by the opposing surface portions.

In some embodiments, the cutting element is defined by a ridge in a top surface of the first block facing the second block, the top surface comprising one of said opposing surface portions, which is arranged with a first angle to an alignment plane of the first and second blocks and extends from the ridge towards a front surface of the first block facing the textile work product, the top surface further comprising a rearward surface portion which extends from the ridge and faces away from the front surface, said rearward surface portion being arranged with a second angle to the alignment plane, the second angle being smaller than the first angle.

In some embodiments, the control device is further configured to, after operating the corner finishing device to pull the end portion in the first direction, operate the heat sealing unit to relatively move the first and second blocks into pressing engagement with the end portion and operate an energy source to provide energy to at least one of the first and second blocks to apply the heat seal to the end portion.

In some embodiments, the energy source comprises an ultrasonic generator unit.

In some embodiments, the apparatus further comprises a position sensor which is fixedly connected to the corner finishing device and arranged to detect the first edge, and the control device is configured to operate said at least one of the conveyor and the corner finishing device to arrange the textile work product adjacent to the corner finishing device based on a sensor signal from the position sensor.

In some embodiments, said conveyor comprises an elongated moveable element which is configured to engage the textile work product while extending parallel to and being spaced from the second edge.

In some embodiments, the textile work product further comprising a third edge that meets the second edge at a further corner at substantially right angles, the binding tape being attached to the second edge so that a further end portion of the binding tape projects beyond the further corner in a direction of the second edge, said apparatus further comprising a further corner finishing device, wherein the control device is operatively connected to the further corner finishing device and is configured to, while operating said at least one of the conveyor and the corner finishing device to arrange the textile work product with the corner in alignment with the corner finishing device, operate said at least one of the conveyor and the further corner finishing device to arrange the textile work product with the further corner in alignment with the further corner finishing device, and operate the further corner finishing device to apply a further heat seal to the further end portion at the further corner and cut the further end portion at the further heat seal to close the binding tape at the further corner.

In some embodiments, the corner finishing device is configured to apply the heat seal by ultrasonic welding.

In some embodiments, the apparatus further comprises an edge binding device, and the control device is configured to operate the edge binding device to attach the binding tape to the second edge so that the end portion of the binding tape projects beyond the corner in the direction of the second edge.

In some embodiments, the control device is further configured to, before operating the edge binding device to attach the binding tape to the second edge, operate the edge binding device, or a further edge binding device, to attach a further binding tape to the first edge so that an end portion of the further binding tape is level with the corner in a direction of the first edge.

A second aspect is a method of edge binding a textile work product having a perimeter comprising first and second edges that meet at a corner at approximately right angles, a binding tape being folded around and attached to the second edge so that an end portion of the binding tape projects beyond the corner in a direction of the second edge. The method comprises: arranging the textile work product with the corner in alignment with a corner finishing device; and operating the corner finishing device to apply a heat seal to the end portion at the corner and cut the end portion at the heat seal to close the binding tape at the corner. The arranging comprises: arranging the end portion to extend through a heat sealing unit of the corner finishing device; operating the heat sealing unit to form a slot with the end portion extending through the slot, a height of said slot being smaller than a thickness of the binding tape on the second edge; and pulling the end portion through the slot in a first direction to thereby drive the corner towards, and optionally into contact with, the slot.

In some embodiments, said pulling comprises: operating a gripping unit to engage the end portion, and operating at least one of the gripping unit and the heat sealing unit to pull the end portion in the first direction.

In some embodiments, the corner finishing device comprises a cutting unit integrated with the heat sealing unit, and said operating the corner finishing device to apply the heat seal comprises: operating the corner finishing device to concurrently apply the heat seal by the heat sealing unit and cut the end portion by the cutting unit.

In some embodiments, the corner finishing device comprises first and second opposing blocks that are mutually moveable and define a cutting element and a stop for the cutting element, respectively, and said operating the heat sealing unit to form the slot comprises: mutually moving the first and second blocks to form the slot between the cutting element and the stop.

In some embodiments, the cutting element and the stop are arranged to extend in a second direction at right angles to the first direction, and said arranging the textile work product comprises: arranging the textile work product with the second edge substantially parallel to the first direction and the first edge substantially extending along the cutting element and the stop in the second direction.

In some embodiments, the first and second blocks comprise opposing surface portions that collectively define a heat sealing region between the first and second blocks, and said operating the heat sealing unit to form the slot causes the opposing surface portions to jointly define a tapered space, and said pulling the end portion in the first direction causes the corner to be received in the tapered space.

In some embodiments, said operating the corner finishing device to apply the heat seal comprises: operating the heat sealing unit to relatively move the first and second blocks into pressing engagement with the end portion and operating an energy source to provide energy to at least one of the first and second blocks to apply the heat seal to the end portion.

In some embodiments, said arranging the textile work product with the corner in alignment with the corner finishing device is at least partly based on a sensor signal from a position sensor which is fixedly connected to the corner finishing device and arranged to detect the first edge.

In some embodiments, said arranging the textile work product with the corner in alignment comprises: moving an elongated element, which is engaged with the textile work product in parallel to and spaced from the second edge.

In some embodiments, the textile work product further comprises a third edge that meets the second edge at further corner at approximately right angles, the binding tape being attached to the second edge so that a further end portion of the binding tape projects beyond the further corner in a direction of the second edge, the method further comprising: concurrent with said arranging the textile work product with the corner in alignment with the corner finishing device, arranging the textile work product with the further corner in alignment with a further corner finishing device, and the method further comprising: operating the further corner finishing device to apply a further heat seal to the further end portion at the further corner and cut the further end portion at the further heat seal to close the binding tape at the further corner.

In some embodiments, the corner finishing device is operated to apply the heat seal by ultrasonic welding.

In some embodiments, the method further comprises: operating an edge binding device to attach the binding tape to the second edge so that the end portion of the binding tape projects beyond the corner in the direction of the second edge.

In some embodiments, the method further comprises, before said operating the edge binding device to attach the binding tape to the second edge, operating the edge binding device to attach a further binding tape to the first edge so that an end portion of the further binding tape is level with the corner in a direction of the first edge.

Still other objectives, as well as features, embodiments, aspects and technical effects will appear from the following detailed description, the attached claims and the drawings.

Embodiments will now be described in more detail with reference to the accompanying schematic drawings.

Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the subject of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure may satisfy applicable legal requirements.

Also, it will be understood that, where possible, any of the advantages, features, functions, devices, and/or operational aspects of any of the embodiments described and/or contemplated herein may be included in any of the other embodiments described and/or contemplated herein, and/or vice versa. In addition, where possible, any terms expressed in the singular form herein are meant to also include the plural form and/or vice versa, unless explicitly stated otherwise. As used herein, "at least one" shall mean "one or more" and these phrases are intended to be interchangeable. Accordingly, the terms "a" and/or "an" shall mean "at least one" or "one or more", even though the phrase "one or more" or "at least one" is also used herein. As used herein, except where the context requires otherwise owing to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, that is, to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments.

It will furthermore be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing the scope of the present disclosure.

The present disclosure relates to techniques for improving production of textile products with edge binding, for example with respect to production rate, production cost or product quality. As used herein, a "textile product" is a product comprising any textile material (e.g., fabric), or a combination of textile materials, each comprising a network of natural or artificial fibers. The respective textile material may be formed by, e.g., weaving, knitting, crocheting, knotting, tatting, felting or braiding. Non-limiting examples of textile products include household textiles, such as mattress covers, bedspreads, bed sheets, quilted textiles, placemats, pillows, throw rugs, seat cushions, towels, pot-holders, curtains, draperies, etc., as well as technical textiles, such as filters, geotextiles, agrotextiles, industrial textiles, etc. It is also conceivable that the textile product with the edge binding is subject to further processing, for example for inclusion in an aggregated product such as a pillowcase, a mattress, etc..

Further, as used herein, a "textile work product" designates any intermediate product which is formed during manufacture of the textile product and onto which the edge binding is provided.

As used herein, "edge binding" has its conventional meaning of designating a process of attaching a protective tape or strip ("binding tape") onto the perimeter, or a portion thereof, of a textile work product. The term edge binding may also refer to the binding tape as attached to the textile work product. The binding tape as attached is also denoted "tape-edge" in the art. The binding tape may comprise a textile material, or a combination of textile materials. For example, the binding tape may comprise a knit or woven textile material. In some embodiments, the binding tape is configured to enable heat sealing, at least onto itself. For example, such a binding tape may be pliable or moldable at elevated temperature and may solidify upon cooling to room temperature. In some embodiments, the binding tape may comprise at least one thermoplastic substance. For example, the thermoplastic substance(s) may be dispersed within the binding tape or be provided in one or more layers on the binding tape.

As used herein, "heat sealing" designates a process of applying heat, and optionally pressure, onto two or more elements to fuse or join the elements. Heat sealing is also known as welding or thermal fusion. Heat sealing results in a heat seal or weld between the elements, at which at least one of the elements is melted and fused with the other element(s).

<FIG> is a top plan view of a textile product <NUM>, which has been provided with an edge binding in conventional manner. The textile product <NUM> comprises a textile work product <NUM>, which has a perimeter with rounded corners. A binding tape <NUM> has been folded over and attached to the edge of the textile work product <NUM> to extend continuously along the entire perimeter. The tape <NUM> may be attached by any conventional technique, such as conventional sewing, laser sewing, seam welding, gluing, etc. In <FIG>, as well as other drawings herein, the attachment of the binding tape <NUM> is represented by a dashed line extending along the tape <NUM>.

Embodiments of the present invention are based on the insight that the production rate in automated production of textile products with edge binding might be increased by dispensing with the requirement for continuous edge binding and rounded corners, and instead attach individual strips of binding tape to the different edges of the textile work product so that the strips of binding tape overlap at the corners of the textile work product. By attaching individual strips to the edges, the edge binding may be accomplished by purely linear motions of the textile work product and/or the processing equipment, which greatly speeds up production compared to the advanced motion required for producing rounded corners. To ensure an aesthetically appealing edge binding, the attached strips of binding tape should substantially conform to the shape of the respective corner. Further, since the strips of binding tape are folded over the respective edge, one of the strips at each corner will be open. This may be undesirable for a number of different reasons, including accumulation of dirt, reduced durability, reduced stability, and lack of customer acceptance. Embodiments are based on the further insight that the open ends of the respective strip may be closed in a simple and durable manner by, e.g., heat sealing.

In the following, embodiments will be described with reference to a schematic example of a production line for manufacturing a textile product <NUM> with edge binding, shown in <FIG>. The production line comprises a sequence of stations <NUM>-<NUM>, which may be arranged in one factory or distributed among different factories. Some of the production steps performed by the stations are further exemplified in <FIG>. The supply station <NUM> is configured to provide a continuous web <NUM>' of raw material for the production of the textile product <NUM>. The raw material may be a sheet material, which may or may not be pre-processed and may or may not comprise a combination of textile materials. <FIG> is a top plan view of such a continuous web <NUM>' being fed from a supply 10A, for example a roll or a bundle. A buffer station <NUM> is arranged intermediate the supply station <NUM> and the cutting station <NUM> and is operable to accumulate the web <NUM>' while it is being cut in the cutting station <NUM>. The buffer station <NUM> thus forms a buffer between the continuous feed from the supply station <NUM> and the intermittent cutting operation in the cutting station <NUM>. The top plan view of <FIG> illustrates a textile work product <NUM> which has been separated from the web <NUM>' in the cutting station <NUM>. In the illustrated example, the textile work product <NUM> is substantially rectangular and comprises two opposing long edges 2a ("longitudinal edges") and two opposing short edges 2b ("lateral edges"). In accordance with an embodiment, the edge binding station <NUM> is configured to apply a respective binding tape to the edges 2a, 2b and trim and seal the binding tapes <NUM> where they meet at the corners 2c. <FIG> illustrates a first processing stage in station <NUM>, at which a binding tape <NUM> is folded around and attached to the respective long edge 2a by a binding device <NUM> ("edge binding device") which is moved along the respective long edge 2a. The binding device <NUM> may, for example, include a sewing machine that provides a seam of stiches along the respective tape <NUM>. <FIG> illustrates a second processing stage in station <NUM>, at which the short edges 2b are trimmed by a cutting or trimming device <NUM> which is moved along the respective short edge 2b to ensure that the ends of the tape <NUM> are substantially level with the edges 2b. The trimming device <NUM> may be of any conventional type, e.g., including one or more of a drag knife, a tangential knife, a rotary knife, a wheel knife, an oscillating/reciprocating knife, a laser cutter, etc. Depending on implementation, the trimming device <NUM> may also cut off a portion of the textile work product <NUM> to form new short edges 2b. After completion of the second stage, the long and short edges 2a, 2b meet at the corners 2c at substantially right angles, subject to manufacturing tolerances which, e.g., may be ±<NUM>° or less, ±<NUM>° or less, or ±<NUM>° or less. <FIG> is a side view taken in direction 3D in <FIG>. As seen, the tape <NUM> is folded around the edge 2a into a generally U-shaped configuration and attached on opposing sides of the textile work product <NUM>, in this example by a seam <NUM>. In the illustrated example, the edges of the tape <NUM> are further turned under ("hemmed") before attachment to prevent fraying. <FIG> illustrates a third processing stage in station <NUM>, at which a binding tape <NUM> is folded around and attached to the respective short edge 2b by a binding device <NUM> ("edge binding device") which is moved along the respective short edge 2b. The binding device <NUM> may be similar to the binding device <NUM>. After completion of the third stage, as shown in <FIG>, end portions <NUM> ("projecting ends") of the binding tape <NUM> on the short edges 2b project beyond the corners. <FIG> illustrates a fourth processing stage in station <NUM>, at which the respective corner is aligned with a corner processing device <NUM>, denoted "corner finishing device" in the following, which is configured to apply a heat seal to the respective projecting end <NUM> and cut the projecting end at the heat seal to close and finish the binding tape <NUM> at the respective corner. <FIG> is a top plan view of the textile product <NUM> after completion of the processing in station <NUM>. As seen, the attached strips of binding tape <NUM> overlap and meet substantially at right angles at the corners. <FIG> is a side view taken in direction <NUM> in <FIG> and shows that the binding tape <NUM> that is folded onto the short edge 2b has been closed by a heat seal <NUM> where this binding tape <NUM> meets the long edge 2a, i.e. at the corner. Thus, as used herein, a binding tape being closed "at the corner" of the textile work product designates a binding tape that is folded and attached along a first edge of the textile work product and extends to a corner where first edge meets a second edge of the textile work product, the binding tape being closed from the corner and over the extent of the binding tape along the second edge. As seen in top view, <FIG>, the overlapping binding tapes are finished to form a substantially right-angled corner of the textile product <NUM>. This is achieved by ensuring that the heat seal <NUM> is located substantially flush with the binding tape <NUM> that is attached to the long edge 2a. In this context, "substantially flush" infers that the heat seal <NUM> projects less than about <NUM>, and preferably less than about <NUM>.

Reverting to the example of the production line in <FIG>, the textile product <NUM> is received by a weighing station <NUM>, which is configured to determine the weight of the textile product <NUM> for quality assessment. If the weight is within acceptable limits, the textile product <NUM> is conveyed to a folding or rolling station <NUM>, which is configured to fold and/or roll up the textile product <NUM>, assuming that the textile product is so large that this is necessary. The folded/rolled textile product is then conveyed to a packaging station <NUM>, which is configured to apply a wrapping onto one or more textile products and/or arrange one or more textile products in an external packaging, such as a bag or carton.

It should be emphasized that <FIG> are merely presented as an example and are in no way intended to be limiting. Any of the stations <NUM>-<NUM>, <NUM>-<NUM> upstream and downstream of the edge binding station <NUM> may be omitted. Further, the edge binding station <NUM> may be configured to first attach the binding tape to the short side 2b and then to the long side 2a. Of course, the textile product may also be produced with all edges of equal length. It is also conceivable that the binding tape is only applied onto one of the two edges that meet in a corner. For example, the textile product may be produced with edge binding only on the long edges 2a or the short edges 2b, or even on one edge only. In these variants, the heat seal <NUM> should be located substantially flush with the edge that meets the edge with the binding tape at the corner.

In the example of <FIG>, the binding devices <NUM>, <NUM> and the trimming devices <NUM> are moved in relation to the textile work product <NUM>, which is immobilized during the respective processing stage. In an alternative, the textile work product <NUM> is moved during one or more of these processing stages, e.g., in relation to one or more of the binding devices <NUM>, <NUM> and trimming devices <NUM>. Any number of binding devices <NUM>, <NUM> and trimming devices <NUM> may be operated on the textile work product <NUM>. To increase production speed, it may be preferable to concurrently operate two binding devices <NUM>, <NUM>, two trimming devices <NUM>, and four corner finishing devices <NUM> on the textile work product <NUM>, as indicated in <FIG>.

<FIG> is a flow chart of an example control method <NUM> for operating the edge binding station <NUM>. The method <NUM> may be performed by a control device ("controller") of the edge binding station <NUM>. The method <NUM> will be presented with reference to the example in <FIG>. In step <NUM>, the binding device <NUM> is operated to fold and attach a first binding tape <NUM> to a first edge of the textile work product <NUM>. The first edge may be a long edge 2a as shown in <FIG>, or a short edge 2b. In step <NUM>, the trimming device <NUM> is operated to trim the first binding tape <NUM> at the corner where the first edge meets a second edge of the textile work product, and possibly also trim the second edge, for example as shown in <FIG>. In step <NUM>, the binding device <NUM> is operated to fold and attach a second binding tape <NUM> to the second edge, for example as shown in <FIG>. In step <NUM>, the textile work product <NUM> is arranged with its corner in alignment with the corner finishing device <NUM>, for example as shown in <FIG>. In step <NUM>, the corner finishing device <NUM> is operated to apply a heat seal <NUM> to the projecting end <NUM> of the second binding tape <NUM> at the corner and cut away the projecting end <NUM> at the heat seal, to thereby close and finish the end of the second binding tape <NUM> at the corner.

<FIG> depict an example of the corner finishing device <NUM> during steps <NUM>-<NUM>. <FIG> is a top plan view during step <NUM>, and <FIG> are elevated side views during step <NUM> and step <NUM>, respectively. In the illustrated example, the textile work product <NUM> is arranged between two overlapping conveyor belts <NUM>, which have been operated to transport the textile work product <NUM> in an infeed direction D1 to the corner finishing device <NUM> in <FIG>. Although the following description refers to the conveyor belts, it should be understood that the any suitable transportation system, generally denoted "conveyor" herein, may be implemented for engaging and transporting the textile work product <NUM>, such as belt systems, roll feeders, grip feeders, etc. The corner finishing device <NUM> comprises a heat sealing unit <NUM>, which is the illustrated example is configured to also operate as a cutting unit. A support 41a is arranged in vertical alignment with the heat sealing unit <NUM> to provide a planar support surface for the textile work product <NUM>, or at least the second edge with the binding tape <NUM> to be heat sealed. A position sensor <NUM> is arranged in registration with the heat sealing unit <NUM> to sense the perimeter of the binding tape <NUM> on the first edge and thereby the location of the corner 2c between the first and second edges. In the illustrated example, the position sensor <NUM> is elongated and arranged to extend parallel to the infeed direction D1. In this example, the position sensor <NUM> comprises an upper and a lower part, which are arranged on opposite sides of the textile work product <NUM>. The position sensor <NUM> is preferably non-contacting and may be of any suitable type, e.g. optical, inductive, magnetostrictive, hall effect, etc. The heat sealing unit <NUM> is moveable in a direction D2 parallel to the infeed direction D1 (<FIG>). The heat sealing unit <NUM> comprises two opposing blocks 42a, 42b which are relatively moveable in a vertical direction D3. Thereby, the heat sealing unit <NUM> is operable in an infeed state, in which the blocks 42a, 42b define a gap for receiving the projecting end <NUM> (<FIG>), and a sealing state, in which the blocks 42a, 42b close the gap around the projecting end <NUM> (<FIG>). In the sealing state, the heat sealing unit <NUM> is operated to supply energy to at least one of the blocks 42a, 42b to form the heat seal in the binding tape <NUM> at the corner 2c. In the illustrated example, the heat sealing unit <NUM> is configured to form the heat seal by ultrasonic welding. Further, as shown, the top surface of block 42a comprises a ridge which is configured to cut the binding tape <NUM> in the second sealing state, i.e. concurrent with the heat sealing. Although not shown in <FIG>, the ridge is arranged to extend perpendicular to the infeed direction D1. Thus, in the illustrated example, blocks 42a, 42b have the function of a cutting element ("knife") and a stop ("opposing support") for the cutting element, respectively.

During execution of the control method <NUM> of <FIG>, the textile work product <NUM> is first transported by the conveyor belts <NUM> into the position in <FIG> with the heat sealing unit <NUM> in the infeed state (step <NUM>). Then, when the textile work product <NUM> is immobilized, the heat sealing unit <NUM> is first moved in direction D2 based on a position signal from the sensor <NUM>, to align the corner 2c with the heat sealing unit <NUM>, as shown in <FIG> (step <NUM>). After fixing the heat sealing unit <NUM> in alignment with the corner 2c, the heat sealing unit <NUM> is set in the sealing state to form the heat seal and cut away the projecting end <NUM>, as shown in <FIG> (step <NUM>). The positional adjustment of the heat sealing unit in direction D2 is optional, but will relax the requirement on the positional accuracy of the conveyor belts <NUM> when transporting the textile work product to the heat sealing unit <NUM>.

Generally, the heat sealing unit <NUM> may be configured to implement any suitable heat sealing technique, including but not limited to ultrasonic welding, hot air welding, hot wedge welding, RF welding, and laser welding. In an alternative to the example in <FIG>, the cutting operation may alternatively be performed by a separate cutting unit subsequent to the heat sealing. In the example of <FIG>, the lower block 42a is stationary and the upper block 42b is moveable. In other variants, the lower block 42a is moveable and the upper block 42b is either moveable or stationary. Further, the ridge may instead be provided on the upper block 42b, or on both blocks 42a, 42b.

The present applicant has identified an opportunity to further improve production by relaxing the need for precise positioning of the heat sealing unit <NUM> relative to the textile work product <NUM>. Such relaxation could be converted into a reduced cost and/or complexity of the production equipment, for example the position sensors <NUM> and drive units for positioning the heat sealing unit <NUM>. The relaxation may also enable increased production rate and/or more consistent quality of the textile products <NUM>. It should also be noted that the textile work products typically are pliable and may be become slightly deformed during processing in the edge binding station <NUM>. Such deformation may reduce the quality of the finished corners.

<FIG> is a flow chart of a control method <NUM> for operating the corner finishing device <NUM> in accordance with an embodiment that relaxes the need for precise positioning. The method <NUM> may be performed by a control device ("controller") of the corner finishing device <NUM>. Steps <NUM>-<NUM> correspond to step <NUM> in <FIG> and will be presented with reference to the arrangement of binding tapes shown in <FIG>. In step <NUM>, the projecting end of the binding tape on the second edge is arranged to extend through the heat sealing unit, which may have the same configuration as the heat sealing unit <NUM> in <FIG>. In step <NUM>, the heat sealing unit is operated to form a restriction slot. The restriction slot has a height that is smaller than thickness of the binding tape on the first edge. The height is the lateral extent of the elongated opening defined by the restriction slot, i.e. taken in a direction perpendicular to the longitudinal direction of the opening. Since the projecting end is arranged by step <NUM> to extend through the heat sealing unit, step <NUM> will cause the restriction slot to form around a portion of the projecting end, and the corner between the first and second edges is located outside the restriction slot. In step <NUM>, a pulling device is operated to pull the projecting end through the restriction slot to thereby drive the corner towards, and optionally into contact with, the restriction slot. Due to its height, the restriction slot will not permit the corner to pass through the slot. By step <NUM>, the corner will attain a well-defined position in relation to the heat sealing unit. In step <NUM>, which corresponds to step <NUM> in <FIG>, the heat sealing unit is operated to close the slot and apply a heat seal to the projecting end and cut away the projecting end at the heat seal, to thereby close and finish the end of the binding tape at the corner. It is realized that steps <NUM>-<NUM> will firmly position the corner in relation to the restriction slot and thereby relax the need to precisely locate the heat sealing unit in relation to the corner in step <NUM>.

The method <NUM> will be further exemplified with reference to <FIG> which depict a corner finishing device <NUM> in accordance with an embodiment, <FIG> being elevated side views and <FIG> being a top plan view. The corner finishing device <NUM> comprises a support 41a, heat sealing unit <NUM>, and a position sensor <NUM>, which may be arranged as described for the example in <FIG>. The position sensor <NUM> is only shown in <FIG>. Although not shown in <FIG>, conveyor belts are arranged to feed the textile work product <NUM> into the corner finishing device <NUM>, as described for the example in <FIG>. The corner finishing device <NUM> further comprises a gripping unit <NUM>, which comprises a pair of gripping elements <NUM>, in this example configured as plates. The gripping unit <NUM> is operable in an infeed state, in which the gripping elements <NUM> are separated, and a gripping state, in which the gripping elements <NUM> are pressed together. Compared to the example in <FIG>, the heat sealing unit <NUM> is operable in an intermediate state, in addition to the infeed state and the sealing state. In the intermediate state, the blocks 42a, 42b are relatively adjusted to form the restriction slot.

In step <NUM>, the conveyor belts are operated to transport the textile work product <NUM> into the corner finishing device <NUM> with the heat sealing unit <NUM> and the gripping unit <NUM> in the infeed state (<FIG>). Also in step <NUM>, when the textile work product <NUM> is immobilized, the heat sealing unit <NUM> may be moved in the direction D2 based on the position signal from the sensor <NUM>, to approximately align the corner 2c with the heat sealing unit <NUM> (<FIG>). The translation of the heat sealing unit <NUM> in direction D2 may relax the requirement for positioning accuracy by the conveyor belts and compensate for small size variations between textile work products <NUM> and/or deformation of the textile work products <NUM>. In step <NUM>, the heat sealing unit <NUM> is fixed in position and set in the intermediate state (<FIG>). In the example of <FIG>, block 42b is thereby moved vertically in direction D3 to define the restriction slot in relation to block 42a. As understood from the foregoing, the distance between the blocks 42a, 42b is smaller than the vertical thickness of the binding tape <NUM> as attached to the first edge and thereby also smaller than the vertical thickness of the corner 2c. Also in step <NUM>, after or concurrent with setting the heat sealing unit <NUM> in the intermediate state, the gripping unit <NUM> is set in the gripping state, to thereby engage the projecting end <NUM> (<FIG>). In the example of <FIG>, the gripping elements <NUM> are moved in opposite directions D4, D4'. As seen in <FIG>, the grip on the projecting end <NUM> is located on the opposite side of the restriction slot compared to the corner 2c. In step <NUM>, as illustrated in <FIG>, the gripping unit <NUM> may be operated to move the griping elements <NUM> in a direction D5 away from the slot, to thereby pull the projecting end <NUM> through the slot and drive the corner 2c towards the restriction slot. As seen in <FIG>, the blocks 42a, 42b define a tapered space towards the restriction slot from the textile work product, and the corner 2c is guided in this tapered space towards the slot when the projecting end <NUM> is pulled by the gripping unit <NUM>. As also indicated in <FIG>, step <NUM> may also operate the heat sealing unit <NUM> to move in the opposite direction D2, away from the gripping elements <NUM>, to displace the slot away from the gripping elements <NUM>. The opposite movements of the gripping elements <NUM> and the heat sealing unit <NUM> may be performed concurrently. However, performing the movements in sequence may result in a firmer and more well-defined positioning of the corner 2c in relation to the slot. In a further variant of step <NUM>, the gripping elements <NUM> are fixed in position and the heat sealing unit <NUM> is operated to move in the direction D2 to thereby pull the projecting end <NUM> through the slot. <FIG> is a top plan view of the corner finishing device <NUM> during step <NUM>, with the gripping elements <NUM> and the block 42b being omitted for clarity of presentation. It should be noted that the pulling action of the projecting end <NUM> in relation to the restriction slot not only drives the corner into alignment with the slot defined between the blocks 42a, 42b, but also ensures that the second edge is arranged substantially parallel to the slot. To achieve this effect, the directions D2, D5 are preferably substantially parallel to the infeed direction D1 (cf. The resulting alignment of the second edge further relaxes the demand for precision in the transportation of the textile work product <NUM> to the corner finishing device <NUM>. Thus, step <NUM> may ensure that the subsequent cut through the projecting end <NUM> is substantially parallel to the second edge and that the corner 2c is substantially right-angled. In this context, "substantially parallel" infers a difference of ±<NUM>° or less, ±<NUM>° or less, or ±<NUM>° or less. In step <NUM>, as shown in <FIG>, the heat sealing unit <NUM> is set in the sealing state to form the heat seal and cut away the projecting end <NUM>, as described above with reference to <FIG>.

Generally, the gripping unit <NUM> may be configured in any suitable way to engage the projecting end <NUM>. For example, other shapes and/or arrangements and/or number of gripping elements <NUM> may be used. In a further alternative (not shown), the gripping unit <NUM> may impart the pulling action to the projecting end <NUM> without physically engaging the projecting end <NUM>, for example by applying a suction force onto the projecting end <NUM> in direction D5. Thus, the gripping unit <NUM> may comprise a flow generator operable to generate an air flow through a tubular duct which is arranged to open at the heat sealing unit <NUM>.

FIGS 8A-8B illustrate a configuration of the blocks 42a, 42b of the heat sealing unit <NUM> in accordance with an embodiment. The blocks 42a, 42b may be included in heat sealing unit <NUM> of any embodiment described hereinabove and is designed for use with ultrasonic welding. The blocks 42a, 42b are elongated and define "welding surfaces" facing one another. The block 42a forms a cutting element or knife by means of a ridge <NUM> in its welding surface. A planar surface portion <NUM> is angled to extend from the ridge <NUM> to a front surface <NUM> of the block 42a. The front surface <NUM> is configured to be arranged facing towards the textile work product in the corner finishing device <NUM>. As seen in FIG. 8B, the planar surface portion <NUM> is tilted by an angle α in relation to an alignment plane AP for the blocks 42a, 42b. The alignment plane AP is vertical and parallel to the elongated extent of the blocks 42a, 42b. When the heat sealing unit <NUM> is in the sealing state, as indicated in FIG. 8B, a heat sealing region will be defined in the space between the surface portion <NUM> and the welding surface <NUM> of block 42b. The heat sealing region will extend from the ridge <NUM> towards the front surface <NUM>, the extent being given by the supplied amount of energy in relation to the local distance between the surface portion <NUM> and the surface <NUM>, which is planar in this example. Thus, the width of the resulting heat seal is set by the angle α and the supplied amount of energy. Since the projecting end will be cut by the ridge <NUM>, the welding surface of block 42a has been designed by prevent or at least limit the formation of a heat sealing region on the other side of the ridge <NUM>. To this end, the welding surface of block 42a comprises a rearward surface portion <NUM> that extends from the ridge <NUM> and faces away from the front surface <NUM>, where the surface portion <NUM> is arranged with an angle to the alignment plane AP that is smaller than the angle α. In the illustrated example, the angle of the surface portion <NUM> is zero or substantially zero. A connecting surface portion <NUM> extends from the rearward surface portion <NUM> to a rear surface <NUM> of block 42a and may be planar, as shown. The vertical distance between the connecting surface portion <NUM> and the welding surface <NUM> is preferably set to prevent or at least limit heat sealing therebetween.

The embodiment in FIGS 8A-8B implements an underlying principle of configuring the welding surfaces of the blocks 42a, 42b such that the vertical spacing of the welding surfaces between the ridge <NUM> and the rear surface <NUM> exceeds the maximum vertical spacing of the welding surfaces within the heat sealing region on the other side of the ridge, i.e. from the ridge <NUM> towards the front surface <NUM>. This principle, which may be implemented by other configurations of the welding surfaces, concentrates the supplied energy to the heat sealing region and thereby minimizes the required amount of energy to be supplied.

<FIG> is a block diagram of components that may be involved in the control of the corner finishing device <NUM> as exemplified in <FIG>. A controller <NUM> comprises an input interface 100a for receiving a sensor signal from the position sensor <NUM>, and an output interface 100b for supplying control signals. In the illustrated embodiment, the controller <NUM> is connected, via the output interface 100b, to a first driver ("textile conveyor driver") <NUM> for the textile work product, a second driver ("gripper translator") <NUM> for horizontal displacement of the gripping elements <NUM>, a third driver <NUM> ("heat sealing unit translator") for horizontal displacement of the heat sealing unit <NUM>, a generator <NUM> ("heat generator") for energy supply to the heat sealing unit <NUM>, a fourth driver <NUM> ("block translator") for relative movement of the blocks 42a, 42b, and a fifth driver <NUM> ("gripper activator") for relative movement of the gripping elements <NUM>. The respective driver may comprise suitable actuator for imparting a desired movement, for example any one of an electric motor, a stepper motor, a servo motor, a pneumatic actuator, a hydraulic actuator, etc..

The first driver <NUM> is operable to transport the textile work product <NUM> to the corner finishing device <NUM> and may, for example, be connected to drive the conveyor belts <NUM> (<FIG>) or any other suitable mechanism for transporting the textile work product. The second driver <NUM> is operable to move the gripping elements from a starting position in direction D5 and back to the starting position (<FIG>). The third driver <NUM> is operable to move the heat sealing unit <NUM> from a starting position in direction D2 and back to the starting position (<FIG>, <FIG>). The fourth driver <NUM> is operable to move at least one of the blocks 42a, 42b from a starting position in direction D3 and back to the starting position (<FIG>, <FIG>). The fifth driver <NUM> is operable to move at least one of the gripping elements <NUM> from a starting position in direction D4, D4' and back to the starting position (<FIG>). The generator <NUM> will differ depending on heat sealing technique. If the heat seal is formed by ultrasonic welding, the generator <NUM> is an ultrasonic generator unit comprising a power supply for generating an electric signal, and converting and boosting equipment for converting the electric signal into mechanical vibration, as is well known in the art. Within the field of ultrasonic welding, the blocks 42a, 42b are denoted horn (or sonotrode) and anvil (or nest). The horn is configured to apply the mechanical vibration to the parts being welded while being pressed against the anvil. It is understood that any one of the blocks 42a, 42b may form the horn and the anvil, respectively.

It is understood that the controller <NUM> may alternatively be configured to control the corner finishing device <NUM> as exemplified in <FIG>. In such an example, the second and fifth drivers <NUM>, <NUM> are omitted.

Further, the controller <NUM> may also be configured to control one or more of the binding devices <NUM>, <NUM> and the trimming devices <NUM> of the edge binding station <NUM> (<FIG>).

<FIG> illustrate a corner finishing device <NUM> that implements the method <NUM> of <FIG>. To clarify the structure and operation of the device <NUM>, the drive belts (<NUM> in <FIG>) have been omitted in <FIG>. The corner finishing device <NUM> comprises a frame <NUM>, which is arranged for movement along a rail <NUM> (<FIG>). The frame <NUM> carries the heat sealing unit <NUM>, the position sensor <NUM>, the gripping unit <NUM> and the support 41a, which are thus moved in unison with the frame <NUM> along the rail <NUM>. The rail <NUM> is fixed to a stand that carries the drive belts <NUM> and the associated mechanical transmission are arranged on a stationary stand (<FIG>). The movement of the frame <NUM> on the rail <NUM> is actuated by an electric motor <NUM>, which thus implements or is part of the third driver <NUM> of <FIG>. The heat sealing unit <NUM> comprises a holder <NUM> which is connected to the frame <NUM> for sliding motion along a vertical track. The holder <NUM> is fixedly connected to a horn 42b and an ultrasonic generator unit <NUM>. The movement of the holder <NUM>, and thus the horn 42b, along the frame <NUM> is actuated by a pneumatic actuator <NUM>, which thus implements or is included in the fourth driver <NUM> of <FIG>. A replaceable anvil element 42a is releasably mounted in an anvil holder <NUM> which is fixed to the frame <NUM>. The position sensor parts <NUM> are fixedly attached to the frame <NUM>. The gripping unit <NUM> comprises two gripping plates <NUM>, of which an upper gripping plate <NUM> is vertically moveable by a pneumatic actuator <NUM>, which thus implements or is part of the fifth driver <NUM> of <FIG>. The gripping unit <NUM> is arranged for sliding motion on a horizontal portion of the frame <NUM>, and an L-shaped element <NUM> of the gripping unit <NUM> is engaged with a pneumatic actuator <NUM>, which thus implements or is part of the second driver <NUM>. In the illustrated embodiment, a tubular member <NUM> is attached to the frame <NUM> and extends to the gripping unit <NUM>. The tubular member <NUM> is connected for fluid communication with an evacuation device (not shown), which generates a suction force in the tubular member <NUM> to evacuate the projecting ends when released by the gripping unit <NUM> after being cut away from the textile work product.

The heat sealing unit <NUM> further comprises a flange <NUM>, which is fixedly connected to the holder <NUM>, as shown in <FIG>. A counter-support <NUM> is arranged on the frame <NUM> to be engaged by the flange <NUM> when the holder <NUM> is driven vertically, by the actuator <NUM>, towards the anvil 42a. A pneumatic actuator <NUM> is operable to switch the counter-support <NUM> between a retracted position and an extended position in the vertical direction. The switching of pneumatic actuator <NUM> is controlled by a control signal from the controller <NUM> of <FIG>. The operation of the counter-support <NUM> is illustrated in <FIG>, which are elevated side views of the region of the anvil 42a and the horn 42b. In <FIG>, the heat sealing unit <NUM> is in the infeed state and the horn 42b is in an upper vertical position. The counter-support <NUM> has been operated into its extended position. In <FIG>, the heat sealing unit <NUM> is in the intermediate state to form the restriction slot between the horn 42b and the anvil 42a. The actuator <NUM> has been activated to drive the holder <NUM>, and thus the horn 42b, vertically towards the anvil 42a, and the vertical movement has continued until the flange <NUM> hits the counter-support <NUM>. Thereby, the counter-support <NUM> defines the height of the restriction slot with high precision. In <FIG>, the heat sealing unit <NUM> is in the sealing state. The counter-support <NUM> has been operated into its retracted position, and the actuator <NUM> is operated to drive the horn 42b against the anvil 42a with a predefined pressing force, which has been set so that a proper heat seal is formed and the projecting end <NUM> is cut away by the ridge on the anvil 42a. It may be noted that <FIG> do not reproduce the movement of the gripping elements <NUM> during production.

<FIG> is a top plan view of a corner forming apparatus 13A, which comprises four corner finishing devices <NUM> that are arranged to process a respective corner of a textile work product. Thus, the apparatus 13A may implement the fourth processing stage depicted in <FIG>. The textile work product is fed into the apparatus 13A in the infeed direction D1 by drive belts <NUM> driven by an electric motor <NUM>, which thus implements or is part of the first driver <NUM> of <FIG>. The textile work product is moved by the drive belts <NUM> into the apparatus 13A, whereupon the drive belts <NUM> are stopped to immobilize the textile work product (cf. step <NUM> in <FIG>). Each individual corner finishing device <NUM> is then operated to perform steps <NUM>-<NUM> of <FIG>, for example as disclosed with reference to <FIG>. When all corners have been processed, the drive belts <NUM> are activated to move the resulting textile product away from the apparatus 13A in the infeed direction D1, while also moving another textile work product into the apparatus 13A.

<FIG> is a block diagram of an exemplifying structure of the controller <NUM> in <FIG>. Generally, the controller <NUM> may be configured to perform any of the methods described herein, or part thereof, by a combination of software and hardware circuitry, or exclusively by specific hardware circuitry. In <FIG>, the controller <NUM> comprises a control circuit <NUM> responsible for the overall operation of the controller <NUM>. As shown, the control circuit <NUM> may include a processing device or processor <NUM>, which may be or include a central processing unit (CPU), graphics processing unit (GPU), microcontroller, microprocessor, ASIC, FPGA, or any other specific or general processing device. The processor <NUM> may execute instructions <NUM> stored in a separate storage device, such as memory <NUM>, and/or in an internal memory (not shown) of the control circuit <NUM>, in order to control the operation of the controller <NUM>. The instructions <NUM> when executed by the processor <NUM> may cause the controller <NUM> to perform any of the methods described herein, or part thereof. The instructions <NUM> may be supplied to the controller <NUM> on a computer-readable medium <NUM>, which may be a tangible (non-transitory) product (for example magnetic medium, optical disk, read-only memory, flash memory, etc.) or a propagating signal. As indicated in <FIG>, the memory <NUM> may also store data <NUM> for use by the processor <NUM>, for example one or more settings of the respective corner finishing device <NUM>, such as timing data, supplied energy, applied force, etc. The memory <NUM> may comprise one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, a random access memory (RAM), or another suitable data storage device. In an exemplary arrangement, the memory <NUM> includes a non-volatile memory for long term data storage and a volatile memory that functions as system memory for the control circuit <NUM>. The memory <NUM> may exchange data with the control circuit <NUM> over a data bus. Accompanying control lines and an address bus between the memory <NUM> and the control circuit <NUM> also may be present. The memory <NUM> is considered a non-transitory computer readable medium. The controller <NUM> may further include a signal interface <NUM>, which may include any conventional communication interface for wired or wireless communication. The signal interface <NUM> is arranged to output one or more control signals and input one or more sensor signals and may thus correspond to the interfaces 100a, 100b of <FIG>.

While the subject of the present disclosure has been described in connection with what is presently considered to be the most practical embodiments, it is to be understood that the subject of the present disclosure is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

Claim 1:
An apparatus for edge binding a textile work product (<NUM>) that has a perimeter comprising first and second edges that meet at a corner at approximately right angles, a binding tape (<NUM>) being folded around and attached to the second edge so that an end portion (<NUM>) of the binding tape (<NUM>) projects beyond the corner in a direction of the second edge, said apparatus comprising a corner finishing device (<NUM>) and a conveyor (<NUM>, <NUM>) for engagement with the textile work product (<NUM>), and a control device (<NUM>) operatively connected to the conveyor (<NUM>, <NUM>) and the corner finishing device (<NUM>), said control device (<NUM>) being configured to:
operate at least one of the conveyor (<NUM>, <NUM>) and the corner finishing device (<NUM>) to arrange the textile work product (<NUM>) with the corner in alignment with the corner finishing device (<NUM>); and
operate the corner finishing device (<NUM>) to apply a heat seal to the end portion (<NUM>) at the corner and cut the end portion (<NUM>) at the heat seal to close the binding tape (<NUM>) at the corner,
wherein the corner finishing device (<NUM>) comprises a heat sealing unit (<NUM>) which is operable to form a slot with a height that is smaller than a thickness of the binding tape (<NUM>) on the second edge, wherein the control device (<NUM>) is configured to, before operating the corner finishing device (<NUM>) to apply the heat seal, operate at least one of the conveyor (<NUM>, <NUM>) and the corner finishing device (<NUM>) to arrange the end portion (<NUM>) to extend through the heat sealing unit (<NUM>), operate the heat sealing unit (<NUM>) to form the slot with the end portion (<NUM>) extending through the slot, and operate the corner finishing device (<NUM>) to pull the end portion (<NUM>) through the slot in a first direction to thereby drive the corner (2c) towards, and optionally into contact with, the slot.