Improved roman shade

Abstract: An expandable and contractible shade member (1), comprising an assembly of an integral row of parallelly arranged generally tubular cells (2), one on top of the other, with the longitudinal cell axis transverse to the direction of expansion and contraction of the window shade, each cell comprising a top portion (7), a rear wall portion (8), a bottom portion (10) and a front wall portion (6), where the front wall flap portion (6) is freely hanging and defines a surface drooping downwardly from the top portion (7) at least to a juncture of said cell, with an immediately adjacent lower cell when said window shade is in the expanded state, the lower edge of said front wall flap portion being independent of said cell except at its junction with the top portion (7).

Description: This invention relates to an improved window covering. Several publications show cellular shades, wherein a fabric material is formed to define parallel tubular cells extending horizontally across the width of the shade. Air within each of the cells only circulates minimally, such that when expanded the shade provides good thermal insulation. It is of course desirable to make the physical appearance of the shade as attractive as possible. Similarly, it is desirable to make such shades as economically as possible, which requires both that a minimal amount of material be used to form each cell and that the manufacturing process be as expeditious as possible. FR-A-1568745 discloses a screen wherein a plurality of strips of a fabric material are folded about fold lines extending longitudinally and bonded together, the two edges of each strip being bonded to the centre of the successive strip, to form a shade consisting of a plurality of tubular cells. This screen is intended to be used such that the cells extend vertically. US-A-4347887 shows a "thermal shutter", wherein a wide band of material is folded transversely to form a double row column of adjacent cells which are adhesively bonded to one another. This structure is symmetrical, so that both sides of the shade thus formed have essentially the same appearance. US-A-4450027 shows a method and apparatus for fabricating a multiple cell shade wherein a continuous relatively narrow strip of fabric is sharply creased longitudinally in order to define pleats in the shade material. A U-shaped cell structure is thus formed. Successive cells are assembled by applying an adhesive to opposed edges of the folded strips, and adhering each formed strip to the strip making up the next preceding cell. This patent discloses strips that are sharply creased to facilitate the formation of the cells. US-A-4631217; 4676855 and 4677013 show, in Fig. 3, a shade of asymmetrical construction. A rear wall section of each cell is essentially straight or linear when the shade is in its expanded position. The height of these rear wall sections thus defines the spacing of the adjacent cells, while the front of each cell, containing more material, maintains a non-linear shape. This shade is formed by providing an assembly of horizontal parallel cells, by forming the cell structure from a material folded into a Z-shape rather than the U-shape. US-A-4673600 and 4685986 disclose a honeycomb structure and method for its production. The structure is composed of two pleated sheets of material joined along opposing pleats. One embodiment shows an asymmetrical construction having a straight rear face and a pleated front face while in the expanded condition. US-A-4846243 shows a foldable window covering formed of a wide relatively soft material folded transversely to yield a collapsible shade. The front surface of the shade consists of a number of drooping loops formed by doubling the material back on itself. The successive cells are spaced in the expanded position of the shade by a relatively vertical rear wall section of each cell, and the size and shape of the loops depend on the location of the seams by which adjacent cells are joined. This construction is relatively complex and requires a large amount of material per cell. Furthermore, since the shade is formed of a wide strip of material folded transversely, this limits the width of the shade which can thus be formed to the width of the stock material available. The need to fold transversely a wide sheet of material continuously across its width also requires precise alignment and control of the entire sheet of material. According to the present invention there is provided an expandable and contractible shade mamber, comprising an assembly of an integral row of parallelly arranged generally tubular cells, one on top of the other, with the longitudinal cell axis transverse to the direction of expansion and contraction of the window shade, each cell comprising a top flap portion, a rear wall portion, a bottom portion and a front wall portion, in which the front wall flap portion is freely hanging and defines a surface drooping downwardly from the top portion at least to a juncture of said cell with an immediately adjacent lower cell when said window shade is in the expanded state, the lower edge of said front wall flap portion being independent of said cell except at its junction with the top portion, characterised in that said shade member is formed from a plurality of superimposed elongate strips of flexible material with their longitudinal axes extending generally horizontally, the number of said strips being at least equal to the number of cells, said strips having a mid portion and first and second longitudinal edges, each strip being connected to one adjacent cell at said first longitudinal edge and to the other adjacent cell at said mid portion so as to form said flap portion. The Roman shade of the present invention does not use excessive material per cell. Also, it can be formed of a relatively narrow strip of material folded longitudinally, such that the width of the shade is not limited by the width of stock materials available. The shade can be manufactured using essentially known methods and apparatus. The improved Roman shade consists of a number of parallel cells with each cell including a rear wall portion which is substantially vertical or linear when the shade is in its expanded state, a bottom portion extending forwardly from the back wall, and a hanging front wall flap portion defining a generally drooping curved surface extending in a curve from a top portion of the cell downwardly and away from the rear wall portion. The cell front surface may comprise a loop of material, and provided an extremely attractive appearance. In order that the invention may more readily be understood, the following description is given, merely by way of example, reference being made to the accompanying drawings, in which:- Fig. 1 shows a first embodiment of the shade of the invention in its nearly collapsed state; Fig. 2 shows the shade of Fig. 1 in its expanded state; Fig. 3 is a cross-sectional view of one embodiment of the invention in the expanded state showing the individual cell structure of the shade, wherein the front and back faces of the cells comprise the same strip of material; Fig. 4 is a cross-sectional view of the embodiment shown in Fig. 3 in the nearly collapsed state; Fig. 5a through 5f show cross-sectional views of further embodiments of the invention similar to that shown in Fig. 3; Fig. 6 is a cross-sectional view of still another embodiment of the invention in the expanded state showing the individual cell structure of the shade, in which the front face of one cell and back face of an adjacent upper cell are comprised of the same strip of material; Fig. 7 is a cross-sectional view of the embodiment shown in Fig. 6 in the nearly collapsed state; Fig. 8a through 8f show cross-sectional views of various embodiments of the invention similar to that shown in Fig. 6; Fig. 9 is a plan view of a suitable apparatus for fabricating the shade structure according to the method of the present invention; Fig. 10 is a cross-sectional view, taken along lines 10-10 of Fig. 8, of the strip material after the initial folding step for forming the embodiment of Fig. 3, Fig. 10 being drawn to about half the scale of Fig. 3; Fig. 11 is a cross-sectional view, similar to Fig. 10, of the strip material after the initial folding step for forming the embodiment shown in Fig. 6; and Fig. 12 is a cross-sectional view, similar to Fig. 10, of the strip material after the initial folding step for forming the embodiment shown in Fig. 5a-5c and 8a-8c. As shown in Fig. 1 and 2, the shade comprises an assembly 1 made up of an integral row of parallelly arranged generally tubular cells 2, one on top of the other. The assembly of cells 2 is fitted with a bottom rail 3 connected to a lowermost cell and a head rail 4 connected to an uppermost cell (omitted from Fig. 2 for clarity). The assembly is adapted to be fitted into a window opening, for example, with the longitudinal cell axis transverse to the direction of expansion and contraction of the assembly. The motion of the shade between the collapsed state of Fig. 1 and the expanded state of Fig. 2 is controlled by control cords 5 extending from the bottom rail 3 upwardly through the cells 2, and into the head rail 4. The cords are directed by generally conventional control pulleys, guides and the like, and are engaged by a conventional locking dog engaging mechanism (not shown). As typically used, these shades are disposed between opposed surfaces of the casing of a window. The width of the shade is preferably chosen so that the ends of the cells approach the casing closely, such that little air flow takes place through the cells. In this way the air mass in each cell is essentially static, whereby the cells of air form a very effective thermal insulation. As indicated in Fig. 3 the final cells 2 are formed from a plurality of superimposed strips of flexible fabric material joined to one another to make up each cell structure 2. Each cell 2 has a cross-sectional shape including a droopy hanging front wall flap 6 extending downwardly and outwardly from a top portion 7 of each cell, a rear wall portion 8 and a bottom portion 10. The front wall flaps define the front faces of the cells, i.e. those portions which are visible when the shade is in use. The front wall flaps 6 are of sufficient height compared to the rear wall 8 so that the front wall flap of each cell droops downwardly at least as far as the juncture between the cell of which it is a part and the immediately adjacent lower cell, when the shade is in the expanded state. Accordingly, when the shade is in its collapsed state as shown in Figs. 1 and 4, the drooping front wall flap 6 of each cell extends well below the adjacent lower cell. In the embodiment of the invention shown in Fig. 3, the strip material is formed across its width into the front wall flap 6 and rear wall 8 of each cell. One longitudinal side of the strip makes up the front of a cell, and the other longitudinal side of the strip makes up the rear of the same cell. Other embodiments of this construction appear in Figs. 5a-5f. According to the embodiment of the present invention shown in Fig. 6, each completed cell 2 is formed of two strips of material. One strip defines a front wall flap portion 6 and extends downwardly from a top portion 7 of the cell. Another separate strip defines rear wall portion 8 of this cell. In this construction, the back of each cell is formed of the same strip of material as the front wall flap portion of the immediately adjacent lower cell. Each cell is joined by an adhesive bead 9 to the immediately adjacent upper and lower cell. Other embodiments of this construction appear in Figs. 8a-8f. Fig. 7 shows the embodiment of Fig. 6 in the nearly collapsed state. Each cell therefore comprises at least one longitudinal edge portion of one of said superimposed strips, and the number of strips is at least equal to the number of cells. A number of embodiments of the invention may be obtained by varying the shape and structure of the hanging front wall portion. Three principle configurations are described here, and depicted in Figs. 5 and 8. The first is a freely hanging front wall portion terminating at a lower edge, shown in Figs. 5a-5c and 8a, 8b or 8e. The front wall may be substantially straight at 35 terminating in an edge 36 (Figs. 5a, 8a), may be slightly inwardly curved at 37, terminating in an edge 45 (Figs. 5b, 8b) or may be more sharply inwardly curved at 38, terminating in a rearwardly directed edge 34 (Figs. 5c, 8e), the inward curving being for aesthetic reasons. A second embodiment has a front wall 6 which is in the form of a loop which is achieved by doubling the front wall on itself at 40 and joining the edge 42 by adhesive 44 adjacent the top of the front wall. The front wall material may be looped forwardly over itself, as shown in Figs. 5d and 8d, or it may be looped rearwardly over itself, as shown in Figs. 3 and 8c. This shape of front wall portion of course requires that wider edge of unfolded material emerge from the initial strip-folding of the processes used to produce the shades, as discussed below, and that the loop shape be fastened along the strip, preferably by adhesive. Finally, the front wall portion may include an abbreviated loop 41 toward its bottom, as shown in Figs. 6, 5e-5f, and 8f. Again the material may be looped forwardly or rearwardly over itself. Further, the material may be joined across two locations on the same face of the material to form loop 41 as in Figs. 5e and 6, or a more bulbous loop 41 shown in Figs. 5f and 8f may be formed by joining one face of the material to the other face. The front wall portion in any of these embodiments is independent of the juncture of each cell to adjacent cells. That is, the construction of the front wall, and hence the appearance of the shade, may be varied without regard for the juncture between cells. Thus, the numerous embodiments shown in Figs. 5a-5f and 8a-8f may be reached from the same basic cell structure, as indicated earlier. In the completed cell, the construction is asymmetrical in that the front wall flap 6 is preferably of substantially greater height than the rear wall portion 8, and may be shaped in a number of aesthetically pleasing ways. Typically, the lowest part of the front wall portion is level or beneath the juncture of the cell with the directly adjacent lower cell. Also, the front wall portion is not creased perceptibly when the shade is in use, principally for aesthetic reasons. As also indicated in Figs. 3 and 6, the rear wall portion 8 may include a longitudinal crease 11 extending generally along its centre. Such a crease can be formed by pressure and heat applied during the formation of the strip into a cell, as described in detail in US-A-4450027. The crease 11 serves to provide a reference surface by which the strip of material can be guided during the fabrication process. The crease 11 also guides the collapse of the cell, such that the cells collapse uniformly and evenly. In the expanded state of the shade of the invention shown in Figs. 3 and 6, the height of the rear wall 8 effectively defines the spacing of the cells 2. In this way the cells 2 can be made of predetermined height, to effect the desired appearance. Figs. 4 and 7 show the shades of Figs. 3 and 6 in the nearly collapsed state. If used, the creases 11 at the rear of each cell serve to ensure uniform collapsing of the cells. The hanging front wall portions 6 of each cell extend substantially over the next lower cells. Temporary creases may be used to assist in the manufacture of the shade of the invention. A temporary crease can be provided in a number of ways. For example, in order to form a permanent crease in a polyester film material, it is necessary to heat the material to a given temperature while folding it and to press it against a hard surface to form a sharply set crease. However, a temporary crease can be formed during the manufacturing process by pressure with a limited amount of heating. If the shade is then hung and allowed to expand, and the crease is heated above a transition temperature, the polyester material will tend to return to its original shape, so that the temporary crease will effectively disappear. Similarly, a cotton fabric with a water soluble sizing such as starch can be used to form the shade of the invention. Such a sized cotton fabric can be creased as if it were paper. However, the starch can be dissolved if the shade is subsequently hung out and wetted, removing the creases. Similar techniques may be useful with polyester and synthetic materials. Finally, a temporary adhesive can be applied to each strip inside the fold defining the front wall during the assembly process, causing the two sides of the front wall to be temporarily bonded, and holding the cell flat for the manufacturing process without imparting a permanent crease. When the shade has been completed, it can be hung out and the adhesive removed. If a water-soluble adhesive is used, it can simply be washed away. Similarly, the two sides of the front and rear walls can be temporarily bonded during assembly using a known heat sensitive adhesive which self-adheres at temperatures, for example, up to 93°C. If this is used to hold the strips flat during stacking, the temporary creases thus formed can be removed by heating the assembly and pulling the temporary creases out. It is possible to form the shade of the invention from materials which do not crease, such as elastomeric materials. The basic method of forming the assembled cell structures of the embodiment of Fig. 3 includes an initial step of folding the strip of material into a form as shown in Fig. 10. The basic method is fully disclosed, most particularly at column 4, line 4 through column 9, line 55, in the US-A-4450027, the disclosure of which is incorporated herein by reference. In this method each strip of material is typically creased longitudinally along lines parallel to the longitudinal strip axis to create front and rear edge portions which are folded over a mid-portion essentially to meet each other. Next, beads of adhesive are applied along the edges of the creased strips of material, and they are stacked, one on top of the other, on a stacking arm. Pressure is applied to ensure that the adhesive bond is properly formed. According to the present invention, it is desired to avoid creasing the front edge portions and only crease the rear edge portions. The second longitudinal edge is then left unconnected to form the front wall flap portion of the cells. The cells are joined by applying adhesive to only the one folded edge portion and stacking the material. This leaves the free edge portion to form the front wall flap, which can be shaped, if desired, either as part of the strip-forming process of US-A-4450027, or by die-forming subsequent to manufacture of a stacked shade having creased rear edges and unformed front walls. The rear wall portion is formed by the folded rear edge and at least part of the mid-portion. Fig. 9 of the present application show the apparatus of US-A-4450027 as modified for use with the present invention. As shown in Fig. 9 a supply of foldable material 12 is provided by the roll 17. Creasing, to the extent desired as discussed above, is initiated by the creaser assembly 20. As the length of material 12 passes through the creaser assembly, a crease 13 is formed in the material on one side thereof. This may be a temporary crease or may form the permanent crease 11 of Fig. 3. After leaving the creaser assembly 20, the length of material 12 is fed through a folding mechanism 23. This mechanism may be constructed in any suitable manner to fold the length of material longitudinally along the crease line 13. The folding is such as to fold the longitudinal rear edge 55 over one side of the mid-portion 57 of the length of material. Shaping of the other longitudinal edge 56, where desired, is discussed below. The folding of edge 55 is done progressively as the length of material is fed through the folding mechanism 23. The folded condition of the length of material as it exits from the folding mechanism 23 is shown in Figs. 10-12. As there seen, the folding of edge 55 is generally in a sideways V pattern. After folding of the material, it is directed through a crimper assembly 24 tightly to press and squeeze the material so as to form a permanent fold along this line. Depending on the nature of the material, this crimper may or may not be necessary. Roller 22 and the cooperating press rollers 28 and 29 may be used to apply heat and rolling pressure across the material to set the desired crimp permanently at a sharp angle. An adhesive applicator 30 is provided for progressively applying the adhesive longitudinally of the length of material. The adhesive is applied in a continuous length to provide one or more heads 9. The material then moves through the forming apparatus, being led to a stacking area where it is wound about a stacking arm 34 and into a continuous loop with successive portions of the length overlying preceding portions. This forms a plurality of parallelly arranged, superimposed, sequential layers of folded length of material and the adhesive beads 9 are pressed into engagement with the facing side of the folded material to connect the sequential layers together along connection lines running lengthwise of the strip on the rear edge portion and mid-portion of adjacent lengths of strip material. The process of US-A-4450027 is generally useful in forming cells where one edge of the strip material is shaped into the front wall flap portion over the same side of the strip that the other edge is folded over. Such cell structures are shown in Figs. 3, 5a-5c, 5e-5f, and 8d. Alternatively, the process shown in US-A-4676855 in which one edge of the strip material is folded over the opposite side of the strip from the other edge, may be used, whereby one edge of the strip is shaped into the front wall flap portion over the opposite side of the strip from the side which the other edge is folded over as in Figs. 5d, 6, 8a-8c, and 8e-8f. Formation of the front wall flap portion may be achieved in any of several ways. First of all, the front wall flap portion may be left unshaped to hang freely. Alternatively, the front wall flap may be shaped during the strip-forming process described above, in which case the front wall flap will already be formed when the strip material is stacked to construct the cellular assembly. If this method is used, the conventional methods must be modified to accommodate the need for a smoothly curved front wall flap substantially without creases. This primarily requires that the creaser assembly 20 and folding mechanism 23 of Fig. 9 be modified to bend the longitudinal front edge 46 of the material into the desired shape, without permanently creasing the material in any area of the front face of the shade which is visible when the shade is in use. If temporary creases are desired in the longitudinal front edge 56, then creaser assembly wheels 22 or 22' may be used for this purpose, the latter for the method of bending the edge over the opposite side of the strip from the rear edge. Where a simple, curved flap as shown in Figs. 5a-5c and 8a-8c is desired, the rollers 25, 26, 28 and 29 of Fig. 9 would be modified to conform the edge of strip material to such a shape, and would preferably heat set the material as well. Where a loop is to be formed in the front wall flap portion, it is necessary to apply a bead of adhesive 44, shown in Figs. 5d-5f and 8d-8f, to fasten the loop. This may be achieved in a number of ways, one of which would be the addition of a second adhesive application unit 30' to the apparatus of Fig. 9, located prior to the folding mechanism 23. After leaving the folding mechanism, the bond of the adhesive could be secured by pressure from rollers 25, 26, 28 and 29. Figs. 10 and 11 show the strip material as it emerges from folding mechanism 23 when the processes of US-A-4450027 and 4676855 are used, respectively. Alternatively, the front wall flap portion could be shaped subsequent to manufacture of the series of cells by the strip-forming process. Unshaped front wall flap strip edges according to this alternative are shaped around a die or dies while part of an otherwise complete expandable and contractible shade. Fig. 12 shows the strip material as it emerges from the folding mechanism 23 of Fig. 9 when this process is used. In another alternative, the cell can be formed out of an extrudable plastic material. The method of forming the cells then comprises forming the cell directly by extrusion, rather than by folding a continuous strip of material. In some cases it might also be desirable to use both of these and/or other methods of forming the cells in manufacture of a single shade according to the invention, while maintaining a uniform appearance and satisfactory operational characteristics.

Claims: An expandable and contractible shade mamber (1), comprising an assembly of an integral row of parallelly arranged generally tubular cells (2), one on top of the other, with the longitudinal cell axis transverse to the direction of expansion and contraction of the window shade, each cell comprising a top portion (7), a rear wall portion (8), a bottom portion (10) and a front wall flap portion (6), in which the front wall flap portion (6) is freely hanging and defines a surface drooping downwardly from the top portion (7) at least to a juncture of said cell with an immediately adjacent lower cell when said window shade is in the expanded state, the lower edge of said front wall flap portion being independent of said cell except at its junction with the top portion (7), characterised in that said shade member is formed from a plurality of superimposed elongate strips of flexible material with their longitudinal axes extending generally horizontally, the number of said strips being at least equal to the number of cells, said strips having a mid portion and first and second longitudinal edges, each strip being connected to one adjacent cell at said first longitudinal edge and to the other adjacent cell at said mid portion so as to form said flap portion. A shade member according to claim 1, characterised in that the front wall flap portion (6) of each cell terminates in a freely hanging edge (45,46). A shade member according to claim 3, characterised in that the front wall flap portion of each cell is of a curved shape (45,39). A shade member according to claim 1, characterised in that the front wall flap portion of each cell comprises a loop, with the material of said front wall flap portion doubled forwardly over itself and joined to itself in a loop shape. A shade member according to claim 1, characterised in that the front wall flap portion of each cell comprises a loop, with the material of said front wall flap portion doubled rearwardly over itself and joined to itself in a loop shape. A window shade according to claim 5, characterised in that one face of the material is joined to its other face to form a bulbous loop. A shade member according to any preceding claim, characterised in that the rear wall portion (8) of each cell defines a substantially straight surface when said window shade is expanded. A shade member according to claim 7, characterised in that a permanent longitudinal crease (11) is formed in the rear wall portion (8) of each cell to guide and control its expansion and contraction. A shade member according to any preceding claim, characterised in that each cell of the assembly is defined by one strip of material. A shade member according to any one of claims 1 to 8, characterised in that each cell of the assembly is defined by two strips of material, each of said two strips forming portions of two immediately adjacent cells. A window shade comprising a shade member of any of claims 1 to 10 and further comprising:- a) a head rail (4) connected to an uppermost one of said cells (2); b) a bottom rail (3) connected to a lowermost one of said cells; c) control cord means (5) for expanding and contracting said shade. A method for manufacturing at least part of an expandable and collapsible shade member from a strip of flexible material of continuous length having a mid-portion and a first and a second longitudinal edge, said at least part defining a plurality of parallelly arranged, superimposed longitudinal cells, extending at an angle in respect of the direction of expansion and collapse, each cell having a longitudinally extending rear wall portion and a longitudinally extending front face formed with a free hanging front wall flap portion with the flap portion formed by one of the longitudinal edges of the strip, said method comprising the steps of:- a) feeding said strip longitudinally of its length; b) progressively folding said first longitudinal edge of the strip along a first fold line parallel to the longitudinal strip axis over said mid portion, so as to have each said rear wall portion formed by said first longitudinal edge and at least part of said mid portion; c) feeding the folded length of strip according to a continuous loop in a stacking area to form a plurality of parallelly arranged superimposed, sequential layers; d) connecting the sequential layers together along first and second connection lines running lengthwise of said strip, said first connection lines being situated on said first longitudinal edges and said second connection lines being situated on said mid portions; e) leaving that portion of the strip beyond the second connection lines unconnected to the cell below, thereby to form the front wall flap portion of the cells. A method according to claim 12, further comprising the steps of forming a second longitudinal edge of the length of material into a hanging front wall flap portion defining the front face of said cells, the front wall flap portion having a lower end terminating in the second longitudinal edge of the length of material. A method according to claim 12, further comprising the steps of:- forming a second longitudinal edge of the length of material with a hanging front portion defining the front face of the cells; doubling the second longitudinal edge of the length of material over itself to form a loop-shaped hanging front wall flap portion and joining said second edge along the length of material to maintain said front wall flap portion in the loop shape.

Inventors: COLSON WENDELL B, COLSON, WENDELL B.
Applicants: HUNTER DOUGLAS INTERNATIONAL, HUNTER DOUGLAS INTERNATIONAL NV
Application year: 1990
Main classification: E06B9
IPC codes: A47H5, E06B9