METHOD FOR MOUNTING A FABRIC

Abstract: A method of forming a strip-like mounting element (14a) in situ on a side of a flexible, preferably fabric, sheet (16) comprising the steps of providing a thermoplastic, preferably a hot-melt adhesive (14), in a heated state in a longitudinally-extending undercut groove (12) of a longitudinally-elongate receiving member (10), and pressing the side of the sheet (16) against the thermoplastic in a longitudinally-extending opening (13) in the groove (12), whereby one side of the thermoplastic adheres to the sheet and an opposite side of the thermoplastic is removably positioned in the groove of the receiving member.

Description: Method for Mounting a Fabric The invention relates to a method for mounting a flexible sheet, such as a fabric, on a receiving member, such as a shaft of a roller blind or a bottom bar thereof, so as to allow for easy disconnection and reconnection of the sheet to the receiving member. A method for mounting flexible sheets or panels on a receiving member is described in EP 0 481 260 (A2). A strip-like element is used which has a first elongate portion connected to a flexible sheet and a second elongate portion received in a longitudinally-extending undercut groove of the receiving member. The second elongate portion includes an array of pivotably and resiliently flexible, parallel disc-shaped elements which are arranged transversely of the length of the strip-like element. The contours of the disc-shaped elements correspond to the cross-sectional shape of the undercut groove. in order to mount a panel in accordance with EP 0 481 260 (A2), it is necessary to bend the disc-shaped members to one side so that they can then be slid into the undercut groove of the receiving member. Once mounted, the resilient disc-shaped members move back to their original position and lock the panel in the groove. It is, however, not easy to mount the disc-shaped elements initially in a groove of a receiving member or to disconnect thereafter the disc-shaped elements from the groove. This is due, at least in part, to the large number of disc-shaped elements. In order to provide an easier method of connecting, disconnecting and then reconnecting a flexible sheet to a longitudinally-elongate receiving member, such as a roller blind shaft, for example in order clean or replace the sheet, this invention provides a method for forming a strip-like mounting element in situ on a side of the sheet comprising the steps of: providing a thermoplastic, preferably a hot-melt adhesive, in a heated state in a longitudinally-extending undercut groove of an elongate receiving member; and pressing the side of the sheet against the thermoplastic in a longitudinally-extending opening in the groove; whereby one side of the thermoplastic adheres to the sheet and an opposite side of the thermoplastic is removably positioned in the groove of the receiving member. The strip-like mounting element can be formed during the production and assembly of a roller blind by having the its shaft or bottom bar serve as the receiving member. The sheet can also be provided with the the strip-like mouting element, without the roller blind shaft or bottom bar, preferably by forming the strip-like mounting element, using a mandrel having a longitudinally-extending under-cut groove, similar to the under-cut groove of the roller blind shaft or bottom bar. Further aspects of the invention will be apparent from the detailed description below of particular embodiments and the drawings thereof, in which: - Figure 1 is an enlarged schematic detail end view, partly in cross section, of a first step of the method of this invention; a fabric is placed adjacent to a thermoplastic in an undercut groove of a shaft of a roller blind, just prior to the fabric's being adhered to the thermoplastic; Figure 2 is a schematic view of a preliminary step in the method of the invention; one way is shown for providing the thermoplastic in the undercut groove of the shaft of the roller blind, prior to the step of Figure 1 ; - Figure 3 is a schematic view of a second step of the method of this invention; the thermoplastic in the undercut groove of the shaft is melted by heating the fabric adjacent to the thermoplastic to adhere the thermoplastic to the fabric; - Figure 4 is a schematic view of a way of removing the fabric with the adhered thermoplastic from the undercut groove of the shaft after the second step of Figure 3; Figure 5 is a schematic view of the thermoplastic holding the fabric to the undercut groove of the shaft of the roller blind, following the second step of Figure 3; and - Figure 6 is an enlarged schematic detail end view of the undercut groove in the shaft of Figures 1 -5. Figure 1 shows schematically the first step of the method of the invention. A longitudinally-elongate shaft 10 of a roller blind is provided with an upwardly-open longitudinally-extending elongate undercut groove 12 having a longitudinally-extending opening 13 and containing a hot-melt adhesive 14. The groove 12 and its opening 13, as well as the adhesive 14 therein, preferably extend along the entire longitudinal length of the shaft 10. A flexible fabric sheet 16 is provided atop the adhesive 14 and the opening 13 of the groove 12. Figure 2 shows schematically one way of providing the hot-melt adhesive 14 in a fluid form in the undercut groove 12 of the shaft 10 during, or directly after, the final steps of roll-forming the shaft with its groove. Alternatively, the adhesive 14 can be provided in the groove 12 after the shaft 10 has been cut to the desired length. Preferably, the adhesive 14 is provided in the groove 12 during the roll-forming or extrusion of the shaft 10. Preferably, the adhesive 14 is poured in liquid form, i.e., molten state, in the opening 13 in the top of the groove 12, but alternatively, it could be provided in a solid form in the groove as described below. The hot-melt adhesive, while being applied to the groove as shown in Figure 2, conforms to any variation in shape or dimension of the groove and thereby ensures its exact form-fit within the groove. An unbreakable connection of the adhesive with the surface of the groove can be prevented by using an appropriate non-stick surface for the groove. Upon solidification of the hot-melt adhesive 14 within the groove 12 following the step shown in Figure 2, the adhesive becomes a longitudinally- extending, strip-like or ribbon-like, mounting element 14A which can subsequently be remelted so that it will adhere to one side of the fabric sheet 1 6 as described below. Due to shrinkage of the adhesive 14 upon solidification, there is already an inherrent tendency in the strip-like mounting element 14A to release itself from the inner surfaces of the groove 12. Because of the cross-sectional shape of the under-cut groove 1 2 of the shaft 10, as shown in Figures 1 and 6, the strip-like mounting element 1 A assumes substantially the same cross-sectional shape as the groove. In this regard, the form and dimensions of the groove 1 2 are selected to ensure a form-fit between the mounting element 14A and the groove 1 2. This form- fit allows the groove 1 2 to hold the mounting element 14A radially of the shaft 10 but also allows the mounting element to be removed by lifting one of its ends radially away from the shaft and away from the groove and longitudinally of the shaft and groove. In this regard, the groove 12 is preferably shaped, as discussed below with regard to Figure 6, to form a "snap-fit" connection with the mounting element 14A. In the preliminary step of Figure 2, the hot-melt adhesive 1 4 can be applied to the opening 1 3 in the groove 12 in a predetermined amount such that the adhesive projects slightly beyond (i.e., above) the outer circumference of the roller as shown in Figure 1 . This allows the adhesive to be subsequently reheated and adhered to the fabric sheet 1 6 with a flat heating sole 22 shown in Figure 3. The predetermined amount of adhesive 14 can, however, also be less so that the adhesive is only in the groove 1 2, within the circumference of the roller. In that case, a profiled heating anvil 22 would be required to reheat the adhesive and adhere it to the fabric sheet 1 6. In Figure 2, the roll-forming equipment for making the shaft 10 and its undercut groove 1 2 has been shown schematically as a pair of opposed rollers 1 8. This is because such equipment is conventional as seen from US patent 1 355 282 and French patent publication 1 539 1 1 3. A nozzle 20 is positioned at the exit end of the roll-forming device 1 8, and its delivery speed of melted hot-melt adhesive 14 to the groove 1 2 is preferably adapted to the operating speed of the roll-former, so that the adhesive is applied to the groove 1 2 almost immediately after the shaft 1 0 has been roll-formed . Alternatively, the adhesive 14 could be applied later or it could be applied as a solid strip or ribbon to the opening 1 3 in the grooove 1 2. In the latter case, a suitable spool (not shown) could be positioned in registration with the shaft 10 exiting from the roll-former 1 8. Figure 3 shows the second step of the method of this invention for adhering the fabric 1 6 to the strip-like mounting element 14A of the solidified hot-melt adhesive1 4 provided in the undercut groove 1 2 of the shaft 10 as shown in Figure 2. After the fabric sheet 1 6 is placed on top of the opening in the groove 1 2 and on top of the hot-melt adhesive mounting element 1 4A in the groove 1 2, preferably with one edge of the fabric sheet 1 6 parallel and adjacent to the mounting element 14A as shown in Figure 1 , the bottom side of the fabric sheet 1 6 is adhered to the elongated mounting element 14A, using the flat heating sole 22. In this regard, the flat heating sole 22 heats the fabric sheet 1 6 which, in turn, heats and thereby remelts the adjacent underlying portions of the hot-melt adhesive 14. The heating sole 22 also presses against the top side of the fabric sheet, thereby pressing the bottom side of the fabric sheet against the heated hot-melt adhesive. As a result, the adhesive is adhered to the fabric sheet, and the sheet is flush with the outer surface of the shaft 1 0. In manufacturing roller blinds in accordance with this invention, a length of ε roller blind shaft 10, with a strip-like mounting element 14A of a hot-melt adhesive 14 that was pre-applied in an undercut groove 1 2 (as schematically shown in Figure 2), is cut to a length corresponding to that of a consumer's window. A suitable length of a fabric sheet 1 6, preferably adjacent to an edge thereof, is then positioned atop the cut length of shaft 1 0. The fabric sheet is then adhered to the mounting element 1 4A of the shaft by heating and pressing the fabric sheet over the mounting element (as schematically shown in Figure 3) to heat and thereby remelt the hot-melt adhesive 1 4 in the opening 1 3 of the groove 1 2. As soon as the hot-melt adhesive 14 has cooled and resolidified, the fabric sheet 1 6 is securely adhered to the mounting element 14A and securely mounted on the shaft 10. Thereafter, the fabric sheet 1 6 can then be removed from the shaft 1 0 by lifting one longitudinal end of the solidified hot-melt adhesive mounting element 14A that is adhered to the fabric sheet. In this regard, the strip-like mounting element 14A is pulled upwardly, radially away from the shaft 10 and away from the groove 1 2, and longitudinally of the groove and shaft. Thereby, one can completely separate the cooperating shapes of the mounting element and the groove. The fabric sheet 1 6 can also be subsequently replaced on the shaft 10. By pushing the mounting element 1 4A of the fabric sheet downwardly into the groove 1 2, starting at one longitudinal end of the mounting element and progressively then pushing along its entire length, one can completely reattatch the cooperating shapes of the mounting element and the groove. To facilitate removing the mounting element 1 4A with the fabric sheet 1 6 from the under-cut groove 1 2 of the shaft 1 0, one or both longitudinal ends of the mounting element are preferably provided with a small, preferably integral, pull-tab or the like. Alternatively, longitudinal end portions of the groove 1 2 could be subsequently cut away to provide access to the longitudinal ends of the mounting element 1 4A, that had been formed in situ in the groove. In accordance with this invention, the steps of disconnecting and reconnecting the strip-like mounting element 1 4A with the fabric sheet 1 6 from the under-cut groove 1 2 can be easily done by the consumer for cleaning or changing the fabric sheet on the shaft of the roller blind. In this regard, a replacement fabric sheet 1 6 can be made, in accordance with this invention, by forming its mounting element 1 4A in situ on the fabric sheet from a hot-melt adhesive 14 by providing the adhesive in a melted state between a longitudinally-extending undercut groove 1 2 of an elongate receiving member or mandrel and the fabric sheet, whereby one side of the adhesive adheres to the fabric sheet and an opposite side of the adhesive is removably positioned in the groove of the receiving member. The method of the invention eliminates the need for realigning the fabric sheet 1 6 with the shaft 10 when they are reconnected, after having been separated. Also, the elongated strip-like mounting element 14A, provided by this method, replaces doubled-over fabric layers of stiched bead or piping connections for connecting fabric sheets to roller blind shafts. Figure 5 shows an end portion 24 of a fabric sheet 1 6 connected to an under-cut groove 1 2 of a roller blind shaft 1 0. The shaft 1 0, made by roll- forming a sheet metal 26, has a lock seam 28 formed in its side opposite the groove 1 2. (The thickness of the sheet metal 26 is indicated by reference numeral 30, and the inner diameter of the tubular roller shaft is indicated by reference numeral 32) . Figure 6 shows an enlargement of the detail "Y" of Figure 5, but without the hot-melt adhesive, strip-like mounting element 14A and the fabric sheet 1 6, in order to more clearly show a preferred dove-tail configuration of the undercut groove 1 2 and preferred relative dimensions thereof. In this regard, the groove 1 2 is preferably provided with an inner lateral width 34 which exceeds its external lateral width 36 adjacent to the surface of the shaft 1 0. From the opening 1 3 of the groove 1 2 towards its largest inner width 34, there are also preferably two transition wall portions 38 and 40 which terminate in wide angled corners 42 and 44 on laterally opposite side walls of the groove. Furthermore, sharp edges and corners are preferably not present in the groove 1 2. In carrying out the method of this invention, any conventional flexible sheet 1 6 for a roller blind can be used, such as a woven or non-woven fabric, made of natural and/or synthetic fibers, provided the flexible sheet material does not substantially degrade when it is heated to melt the hot-melt adhesive 1 4 of the strip-like mounting element 1 4A. For a flexible fabric sheet 1 6 having interconnected fibers forming interstices therebetween, it is preferred that the hot-melt adhesive 1 4 of the mounting element 14A, when heated and pressed against the fabric sheet, partly encapsulate its fibers. For certain embodiments of the invention, the flexible fabric sheet 1 6 will preferably be washable. Likewise, any conventional thermoplastic, preferably a hot-melt adhesive 14 melting above about 100 degrees C, can be used in the mounting element 1 4A, provided that: i) it can be suitably applied, preferably as a heated liquid, to the opening 1 3 of the under-cut groove 1 2 of the shaft 1 0 to form the mounting element (Figure 2); and it can subsequently be strongly adhered in a heated state (i.e., partially or totally melted) to the fabric sheet 1 6. In this regard, it may be preferred for certain embodiments of the invention that the thermoplastic can also be: i) cooled from its liquid state to solidify it as the mounting element 1 4A, formed in situ in the groove 1 2, and ii) then reheated, preferably reheated through the fabric sheet 1 6, to adhere it to the fabric sheet. However, for other embodiments, this may not be necessary if the originally heated, molten thermoplastic, as applied to the opening 1 3 in the groove 1 2, can soon or preferably immediately thereafter have the fabric sheet 1 6 pressed against it so that they adhere strongly to one another. Likewise, the thermoplastic could be reheated just before the fabric sheet 1 6 is pressed against it to adhere them to each other. Such reheating could also be used to allow a longitudinally-extending thermoplastic bead, placed in the groove 1 2 in solid form, to conform to the shape of the groove to form the mounting element 1 4 either before or after adhering it to the fabric sheet 1 6. Moreover, specific dimensions and configurations of the under-cut groove 1 2 of the shaft 10 and specific temperatures for heating and cooling and optionally reheating and recooling the thermoplastic, preferably hot-melt adhesive 14, are not considered critical. However, the fabric sheet 1 6, the thermoplastic and the dimensions and configurations of the under-cut groove 1 2 must all be selected, so that after heating the thermoplastic to melt it in the groove and adhere it to the fabric sheet and then cooling the thermoplastic to solidify it, the adhesion between the thermoplastic mounting strip 1 4A and the fabric sheet is stronger than the adhesion between the mounting strip and the groove when a longitudinal end of the mounting strip is pulled upwardly, radially away from the shaft and away from the groove and longitudinally thereof (Figure 4). Also, the heating of the thermoplastic is preferably carried out, so that substantially only its surface portions in the opening 1 3 of the groove 1 2 are melted, to avoid having molten thermoplastic leak from the groove 1 2. The invention is, of course, not limited to the above-described embodiments that can be modified without departing from the scope of the invention or sacrificing all of its advantages. In this regard, the terms in the foregoing description and the following claims, such as "upwardly" , "downwardly" , "top" , " bottom", "radial" , "lateral" and "longitudinal" , have been used only as relative terms to describe the relationships of the various elements used in carrying out the method of the invention.

Claims: CLAIMS: 1 . A method of forming a strip-like mounting element (14A) in situ on a side of a flexible, preferably fabric, sheet (1 6) comprising the steps of: providing a thermoplastic, preferably a hot-melt adhesive (14), in a heated state in a longitudinally-extending undercut groove (1 2) of a longitudinally-elongate receiving member (10); and pressing the side of the sheet (1 6) against the thermoplastic in a longitudinally-extending opening (1 3) in the groove (1 2); whereby one side of the thermoplastic adheres to the sheet and an opposite side of the thermoplastic is removably positioned in the groove of the receiving member. 2. The method of claim 1 wherein the receiving member (10) is a shaft of a roller blind. 3. The method of claim 1 or 2 wherein the receiving member (10) is roll- formed and the thermoplastic is provided in the groove (1 2) in a heated state immediately after the receiving member is roll-formed. 4. The method of claim 3 wherein the thermoplastic is then cooled and subsequently reheated just before the sheet (1 6) is pressed against the thermoplastic. 5. The method of claim 3 wherein the thermoplastic is then cooled and subsequently reheated while the sheet (1 6) is pressed against the thermoplastic. 6. The method of claim 5 wherein the thermoplastic is reheated by a heating element (22) pressing the sheet (1 6) against the thermoplastic. 7. The method of any one of claims 1 -6 wherein the groove (1 2) is shaped to releasably hold the mounting element (14A). 8. The method of claim 7 wherein the groove (1 2) is shaped to form a snap-fit connection with the mounting element (1 4A). 9. The method of claim 7 or 8 wherein, from the opening ( 1 3) of the groove ( 1 2) towards its largest inner width, there are two transition wall portions (38 and 40) which terminate in wide angled corners (42 and 44) on opposite side walls of the groove. 1 0. The method of claim 9 wherein there are no sharp edges or corners in the groove (1 2). 1 1 . The method of any one of claims 1 -1 0 wherein the groove (1 2) and its opening ( 1 3), as well as the adhesive ( 1 4) therein, extend along substantially the entire longitudinal length of the receiving member ( 1 0) . 1 2. A flexible, preferably fabric, sheet (1 6) with a strip-like mounting element (1 4A) adhered to one side of it, made by the method of any one of claims 1 -1 1 . 1 3. A flexible, preferably fabric, sheet (1 6) with a strip-like mounting element (14A) that is adhered to one side of the sheet and has an undercut cross-section. 14. A roller blind assembly comprising: a longitudinally-elongate shaft or bottom bar with a longitudinally-extending undercut groove (1 2); and the sheet (1 6) of claim 1 2 or 1 3 with the strip-like mounting element (14A) adhered to one side of it and releasably inserted in the groove. 1 5. A method of applying a strip-like mounting element (14A) of a thermoplastic, preferably a hot-melt adhesive (1 4), to a receiving member (10), comprising the steps of: providing a continuous cross- section (1 2) to the receiving member; then applying the thermoplastic in a molten state lengthwise of the receiving member in the cross- section; and then solidifying the thermoplastic into the strip-like mounting element. 6. A method of applying a flexible sheet (1 6) to a strip-like mounting element ( 14A) of a thermoplastic, preferably a hot-melt adhesive ( 1 4), including the steps of: positioning the sheet in contact with the striplike mounting element; and then applying heat to one or both of them. 7. The method of claim 1 6 wherein the strip-like mounting element (1 4A) is in a groove (1 2) of a receiving member (10) having a continuous cross-section prior to the step of applying heat. 8. A method of connecting a flexible sheet (1 6) to a receiving member ( 1 0), comprising the steps of: positioning a strip-like mounting element (14A) of a thermoplastic, preferably a hot-melt adhesive (1 4), between the receiving member and the sheet and applying heat to any one or all of the sheet, the mounting element and the receiving member. 9. An apparatus for carrying out the method of any one of claims 1 -1 1 and 1 5-1 9 wherein the apparatus comprises at least one pair of opposed forming rolls (1 8) and a nozzle (20) for applying the thermoplastic in a liquid state.

Inventors: WELFONDER KONRAD, WELFONDER, KONRAD
Applicants: HUNTER DOUGLAS IND BV, HUNTER DOUGLAS INTERNATIONAL, WELFONDER KONRAD, HUNTER DOUGLAS INDUSTRIES B.V., HUNTER DOUGLAS INTERNATIONAL N.V., WELFONDER, KONRAD
Application year: 1999
Main classification: E06B9
IPC codes: B60R5, C09J5, C09J7, E06B9