The present invention relates to a method for manufacturing a fabric provided with one or more tunnel loops, in particular for use as a window covering. The present invention furthermore relates to a device for operating a pull-up cord for a window covering and to a window covering, consisting of a fabric provided with tunnel loops, in which rigid elements are inserted, which window covering furthermore comprises a number of pull-up cords.

Such a window covering is known from French patent publication no. 517.502, wherein the tunnel loops extend over the entire width, however. One drawback of such an arrangement is that any pull-up cords that may be present are connected to such tunnel loops, and in particular in the case of voile-type fabrics this will lead to tension in the fabric, which may result in damage, pulling of the fabric or extra wear.

Such a method is known per se from US patent no. 5,662,147.

The method that is known therefrom comprises the provision of a number of loops in the fabric during the weaving process, which loops are arranged in spaced-apart relationship in groups. Said groups of loops function as points of attachment for a so-called guide ring, through which a pull-up cord is passed, which pull-up cord is connected to the lower edge of the fabric. Thus it is possible to use such a fabric as a window covering material, whereby the window covering can be lowered or raised by means of the pull-up cord. A major drawback of this method is the need to use said guide rings. Said rings have appeared to be a vulnerable link in the final product, because they frequently break off after a short time, in particular in case of intensive use. In addition, such rings are

undesirable from an aesthetic point of-view, because the rings are visible through the fabric on the front side when relatively thin fabrics are used. Another drawback of this method is in particular the standard dimension in which such a fabric can be manufactured. As it is, the manufacturing method comprises the production of the fabric in a standard weaving machine, wherein said groups of loops are consistently formed in the transverse direction of the fabric, that is, perpendicularly to the direction in which the fabric is made. Thus, the possibilities of using such a fabric as a window covering are limited, because the actual dimension of the fabric is dictated by the width of the weaving machine.

Present-day house construction is no longer based on standard frame dimensions, however, so that the current window covering materials are no longer satisfactory for a number of applications, in view with the maximum dimensions thereof. In certain situations it is necessary, therefore, to arrange two window coverings side by side in the case of window frames having large dimensions, so as to be able to screen the full dimension of the frame.

A method of this kind is also known from German Offenlegungsschrift no. 44 19 140, wherein the same limitation obtains with regard to the provision of the required loops in the fabric as for the above-discussed US patent no. 5,662,147, in particular with regard to the maximum width, wherein such a fabric can be used as a window covering. In addition, said Offenlegungsschrift mentions the presence of a so-called tubular fabric, which tubular fabric extends over the entire width of the window covering, and which can be regarded as two unconnected woven layers positioned one above the other, between which rigid elements are inserted. Finally, a guide ring must be used for the subsequent provision of pull-up cords, which guide ring has the same drawbacks as mentioned with regard to US patent no. 5,662,147. From European patent application no. 0 794 275 there is furthermore known a method for manufacturing a fabric provided with loops, in particular for

use as a window covering, which method in the main corresponds to the method that is known from German Offenlegungsschrift no. 44 19 410, so that also in this case there are limitations as regards the maximum dimension for use as a window covering-.

Consequently it is an object of the present invention to provide a method for manufacturing a fabric provided with one or more tunnel loops, in particular for use as a window covering, which method eliminates the above-mentioned drawbacks of the prior art.

Another object of the present invention is to provide a method for manufacturing a fabric provided with one or more tunnel loops, in particular for use as a window covering, which method reduces the manufacturing costs for a window covering significantly.

Another object of the present invention is to provide a window covering consisting of an element for operating a pull-up cord, and a fabric provided with one or more rigid elements and pull-up cords connected thereto.

Another object of the present invention is to provide a window covering as referred to above, which window covering reduces the risk of pleats piling up undesirably to a significant extent.

Another object of the present invention is to provide a _device for operating a pull-up cord for a window covering, which device ensures that the forces that may occur upon raising or lowering the window covering will not act on the fabric.

Yet another object of the present invention is to provide a window covering wherein said rigid elements are properly fixed in said tunnel loop, so that movement of said rigid elements is reduced to a minimum.

According to the present invention, the method as referred to in the introduction is characterized in that said tubular strips or tunnel loops are formed in such a manner in the fabric during the weaving process that said tubular strips are interrupted by loops at regular

intervals on one side of the fabric, said tubular strips and said loops being integral with the fabric.

Such loops function as spaces through which the pull-up cords are passed in the window covering. The advantage of this is that it is very easy to insert the rigid elements into the tubular strips and remove them therefrom, that it is not necessary to use guide rings, that a proper fixation of the rigid element is ensured and that, above all, no force is exerted on the fabric upon raising or lowering the window covering.

In a special embodiment of the present method, it is preferable to form the tubular strip in the transverse direction of the fabric, that is, perpendicularly to the direction in which the present fabric is manufactured. In addition to that, it may be preferable to form the continuous tubular strip in the longitudinal direction of the fabric, which longitudinal direction of the fabric is subsequently used as the transverse direction of the window covering. This latter embodiment has the advantage that there are no limitations as regards the width of the window covering.

According to a special embodiment of the present method, the tubular strips are formed in the longitudinal direction of the fabric, in particular by causing specific weft threads to float in the longitudinal direction (warp) of the fabric at said locations, after which the fabric thus manufactured is turned through 90°, which means that the lengths of fabric thus formed are used in transverse direction so as to function as a window covering. Such a method in particular has the advantage that the tubular strips thus formed extend parallel to each other, which is a major advantage in particular upon finishing the fabric to form a window covering. The fact of the matter is that if the tubular strips do not extend parallel to each other, such a fabric will exhibit slightly oblique tubular strips when used as a window covering, which is unacceptable in particular from an aesthetic point of view.

The use of the present fabric in particular has the advantage that the required pull-up cords can be fitted between the regularly spaced-apart loops of the tubular strips without any difficulty and be passed through the rigid-elements thereby, which aspect constitutes an essential difference with the aforesaid US patent no.

5,662,147, wherein separate guide rings are required for passing the pull-up cords therethrough. In addition to that, when the present fabric is used, it is possible at all times to string the pull-up cords in such a manner that they extend straight down.

It is in particular preferable to form a number of rows of tubular strips in the fabric during the weaving process, wherein the spacing between the rows is not constant, and wherein it is in particular preferable for the spacing between the rows of tubular strips to increase progressively.

Since the tubular strips are formed in a continuous row in the fabric during the weaving process, which rows preferably extend in the longitudinal direction of the fabric, the spacing between the tubular strips can be adjusted accurately by suitably controlling the weaving machine. Since it is preferred to have the spacing between the rows of tubular strips increase progressively, it is possible according to the _present invention to obtain a beautifully draped appearance of the window covering in pulled-up condition. In such an embodiment the fabric materials between the tubular strips will slightly overlap, as will be explained in detail in the discussion of the appended figures.

It is in particular preferable to carry out the present weaving process in such a manner that the loops of the tubular strips are present on the fabric, being visible from one side only, in particular the side where the pull-up cords and the rigid elements that are inserted into the tubular strips are present, in particular the back side. On the other side, the front side, the fabric forms a continuous network of warp and weft threads, which has a positive effect as regards the aesthetic

aspect. Since the tubular strips are woven into the material during the weaving process, preferably in the longitudinal direction thereof, no additional stitching operations are required. Moreover, the rigid elements can be slipped into and out of the tubular strips very easily, without causing damage to the fabric.

The material from which the fabric according to the present invention is made is not restricted to any particular material, but it is preferably composed of one or more synthetic materials. In addition to that it is possible to use one or more natural materials, for example cotton. In a special embodiment it is furthermore advisable to subject the fabric to a finishing treatment, for example the so-called thermofixing or a treatment with synthetic resins, so as to give the fabric special properties in this manner, for example making it crease- free and pliable, prevent fraying, making it easier to wash and the like.

In view of the fact that according to the present invention the tubular strips are woven into the fabric in the longitudinal direction thereof during the weaving process, it is moreover very easy to form a pattern in the fabric during said weaving process.

The present invention furthermore relates to a window covering, consisting of an element for operating a pull-up cord and a fabric provided with one or more rigid elements and pull-up cords connected thereto, which window covering is characterized in that the fabric manufactured in accordance with the present method is used.

In the present window covering it is in particular preferable to form recesses in the rigid elements that are to be inserted into the tubular strips, through which recesses the pull-up cords can be passed, wherein the recesses of the rigid elements are located near the position of the regularly spaced-apart loops in the tubular strip. Such recesses ensure that the pull-up cords are passed through the rigid elements, as a result of which both the rigid elements and the pull-up cords will remain precisely in position, which system is used in

particular for light-weight fabrics. In addition, no tension will build up in the voile-type fabrics, which tension might result in damage, pulling of the material or extra wear. Furthermore it is possible for the pull-up cords to be passed through the tubular strips between the fabric and the rigid element.

In a special embodiment of the present window covering it is preferable to interconnect the rigid elements that are present in the tubular strips by means of at least one connecting cord, whose length is shorter than the spacing between the parallel tubular strips. In this manner, flowing draperies will be obtained, as will be explained in detail yet with reference to the figures.

The invention furthermore relates to a device for operating a pull-up cord for a window covering, such as the above-described window covering according to the invention, for example, comprising a housing and a rotatable shaft extending within said housing, which is fitted with a winding element for the pull-up cord. Such a device is known from US patent no. 5,328,113. Said patent discloses a device comprising a housing in the form of a U-shaped section, which is open at the upper side and within which a rotatable shaft extends, which is mounted in bearings near the ends of the housing. A cord extends through an opening in the bottom of the U-shaped section in order to be fixed to a window covering. One free end of the cord is connected to the shaft at a point some distance away (in axial direction) from said opening. At the location of the opening, the shaft comprises a portion having a greater diameter, as well as a shoulder. When the cord is wound up, cord windings are pushed aside by the action of the shoulder, as a result of which said cord windings will slide off the greater diameter portion of the shaft to a smaller diameter portion of the shaft, in the direction of the aforesaid connection between the free end of the cord and the shaft. A major drawback of such a system is the fact that frictional forces will inherently occur between neighbouring windings of the cord mutually as

well as between said windings and said shaft. This leads to the risk of a multilayer winding being formed during winding. Furthermore, the life span of the cord is reduced by said frictional forces and the user will experience increased resistance during use.

The object of the invention is to provide an improved device as described above, which provides a solution for the above- described problems. In order to accomplish that objective, the device is according to the invention characterized in that the winding element is movable in the axial direction of the shaft during rotation of the winding element. By using the movability of the winding element, it becomes possible to keep neighbouring windings completely separated from each other, thus ruling out the occurrence of frictional forces between said winding. In addition, a new surface portion of the winding element can continuously be presented to the pull-up cord during winding, as a result of which the cord no longer needs to move over the surface of the winding element. All this prolongs the life of said at least one pull-up cord, whilst in addition the positive drive ensures correct operation.

A constructionally simple embodiment is obtained if the winding element is movable along the shaft, as a result of which additional longitudinal guides for the winding element are no longer required.

A very advantageous embodiment of the device is obtained if the shaft is of unround shape and extends through a correspondingly shaped central opening in the winding element with some play. As a result, a possibility is on the one hand created to rotate the winding element in a simple manner via the shaft, whilst on the other hand it remains possible for the shaft to function as an axial guide member for the winding element. Within the framework of this preferred embodiment, the term corresponding shape of the central opening is to be understood to mean a shape such that rotation of the shaft leads to rotation of the winding element by transmission of forces via edges of the opening. Such

a result can also be obtained, for example, by using a round shaft provided with a key in combination with an extended keyway, within which the key can move. This in contrast to the traditional keyed connections, wherein there-is also axial retainment.

A very suitable manner of translating rotation of the shaft into movement of the winding element in horizontal direction can be achieved if a supporting element is connected to the housing, against which the winding element is supported during rotation of the winding element. Such a supporting element may also form an integral part of the housing.

It is very advantageous if the winding element is provided with external screw thread for the purpose of co-operating with said supporting element so as to enable said horizontal movement. The pitch of such external screw thread at least partially determines the spacing between neighbouring windings of the pull-up cord on the winding element in coiled condition.

It is furthermore very advantageous if the supporting element includes an opening provided with internal screw thread for the purpose of co-operating with said winding element, for example to mate with external screw thread on the winding element.

The present invention will be explained in more detail hereafter by means of a number of examples, whereby it should be noted, however, that the present invention is by no means limited to any such special example.

Figure 1 is schematic view of a window covering according to the present invention.

Figure 2 is a schematic, sectional view of the tubular strip according to the present invention.

Figure 3 is a schematic, cross-sectional view of the tubular strip according to the present invention, wherein the rigid elements are provided with recesses.

Figure 4 is a schematic view of a prior art window covering in pulled-up condition.

Figure 5 is a schematic view of a window covering according to the present invention in pulled-up condition.

Figure 6 is a schematic view of a special embodiment of a window covering.

Figure 7 is a schematic view of a device for operating a pull-up cord for a window covering according to the present invention.

Figure 1 schematically shows a window covering 1 according to the present invention, consisting of a fabric 2, wherein fabric 2 is provided with a tubular strip 5 on its back side, which tubular strip 5 is present on fabric 2, thus forming an integral part of the fabric. From the figures it is apparent that tubular strip 5 is interrupted by loops at regular intervals, which loops are especially suitable for passing a pull-up cord 4 therethrough. A rigid element 6 is present in each tubular strip 5, through which rigid elements 6 a pull-up cord 4 may be passed, as is schematically shown in Figure 3. Moreover, the pull-up cord 4 can be passed over rigid element 6 in the way that is schematically shown in Figure 2. Such a window covering 1 is fixed to the upper side of a window frame (not shown), using a fixing element 3, and fabric 2 furthermore comprises a weighting element 7 at its lower side. In unrolled condition, as shown in Figure 1, fabric 2 can be raised by pulling at cord 4, in particular using the device as shown in Figure 7, after which the rigid elements 6 thus present in tubular strips 5 are moved towards each other.

Parts corresponding to each other are indicated by the same numerals in the next figures 2-6.

Figure 2 schematically shows a cross-section of the window covering 1 of Figure 1. Rigid element 6 is slipped into a tubular strip 5 in fabric 2, wherein subsequently pull-up cord 4 is strung between rigid element 6 and tubular strip 5 near the position of the loops in the tubular strip 5.

Figure 3 shows the embodiment wherein the rigid element 6 is drilled through or provided with a recess in such a manner that pull- up cord 4 is passed through the rigid element 6 near the position of the loops in the tubular strip 5. Rigid element 6 is positioned in a tubular strip 5 in fabric 2, as has been described in great detail with reference to Figure 1.

Figure 4 schematically shows the embodiment of a window covering according to the prior art wherein the spacing between the rows of loops is constant, so that the respective portions of the fabric 2 are folded onto each other over in such a manner that the fabric exhibits large overlaps in pulled-up condition.

Figure 5, on the other hand, shows the pulled-up condition of a window covering made in accordance with the present method, wherein the spacing between the rows of tubular strips increases progressively, so that the tubular strips are arranged or draped in such a manner that they overlap only slightly. The use of such an embodiment in particular has a positive aesthetic effect.

Figure 6 schematically shows the embodiment wherein the rigid elements 6 that are present in the continuous tubular strips 5 in fabric 2 are interconnected by means of a connecting cord 8. The length of connecting cord 8 is such that fabric 2 has a draped appearance on the front side in the taut condition of the connecting cord, which is desirable in specific embodiments. The pull-up cords that are required, which are shown in Figure 1, have been left out in Figure 6 for the sake of clarity.

Figure 7 shows a preferred embodiment of a device 22 for operating a pull-up cord 13 according to the invention. Device 22 comprises a tubular housing 17. Within the scope of the invention the housing need not be closed or substantially closed for that matter.

Present at the illustrated end of said housing 17 is a rotatable chain wheel 21, with which shaft 15 is connected concentrically. Shaft 15 is of

square cross-section and extends through a, likewise square, through opening 23 of a winding element 11 with some play. Winding element 11 is provided with a shoulder 12 at one free end and with a length of external screw thread 14 at its other end. Present between said shoulder and said screw thread is a cylindrical portion having a smooth surface, onto which the pull-up cord 13 is to be wound. Pull-up cord 13 is connected to shoulder 12 at one end, by means of knot 20, and extends from winding element 11 through opening 24 to be connected to a window covering outside housing 17. External screw thread 14 of winding element 11 mates with the internal screw thread 25 in a supporting element 16 that is fixedly connected to tubular housing 17.

Device 22 is used as follows. Shaft 15 is rotated by suitably pulling down one of the two parts of chain 18 that extend downwards from chain wheel 21. As a result, winding element 11 is rotated as well, on account of the identity of shape of shaft 15 and opening 23.

The mating engagement between external screw thread 14 and internal screw thread 25 causes the winding element 11 to move in horizontal direction along shaft 15 during rotation of winding element 11. As a result, a new surface portion of the winding element 11 is continuously presented to pull-up cord 13, as a result of which neighbouring windings will be _separated from each other. It stands to reason that the distance by which said windings are separated from each other depends on the pitch of the external screw thread 14 and the internal screw thread 25. When pull-up cord 13 is unwound, which is done by pulling at the other part of chain 18, winding element 11 will be moved horizontally in the opposite direction. Stop element 19 on chain 18 ensures that the winding and unwinding device will move in the same winding and unwinding direction at all times.