GB1582862A - Window blinds - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO WINDOW BLINDS (71) We, 101 NOTIONS LIMITED, a British Company of Unit 12a First Floor, St. Michaels Trading Estate, Bridport, Dorest, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates generally to window blinds of the type usually termed "roller blinds" and comprising a sheet of fabric or other flexible material wound on a roller which in use is mounted with its axis horizontal at or adjacent to top of a window. An internal spring biases the roller to a position in which the fabric or other flexible material is rolled up thereon, and the blind can be drawn down to cover the window opening by pulling the lower edge thereof down to a desired position, the roller having latching pawls for retaining it insuch a position.

Roller blinds are usually provided with a stiffening batten or lath along the bottom edge of the fabric or other flexible material sheet in order to hold the blind fabric out in a flat sheet between the roller at the top and the batten or lath at the bottom In known roller blinds the battens or laths are made of wood and inserted into a stitched pocket along the bottom edge of the blind fabric. A pull cord is then attached to the batten or lath by stapling or pinning through the fabric into the wood This conventional construction has a num-- ber of disadvantages, including the labour in stitching the pocket and inserting the lath and fitting the pull- cord accurately at a mid point along the length of the lath.

The present invention seeks to provide a blind bottom lath and an element for forming such a lath in which the above disadvan tages- are overcome.

According to the present invention an element for forming, together with a like such element, a blind bottom lath, comprises as strip of moulding the cross sectional shape of which includes respective male and female parts dimensioned such as to co-- operate with opposite such parts on the said like such element to trap a layer of fabric between the elements whereby to hold å co;mipdsitC lath comprising two such elements, together and to the fabric.

Assembling a blind bottom lath and attaching it to a bottom edge of the fabric of á roller blind can thus conveniently be achieved in one operation utilising a blind bottom lath element in accordance with the present invention. For this the edge of the fabric of the blind is laid over one of the cooperating male and female parts, and a like such element is placed, inverted over the first mentioned element. The two elements are' then pressed together trapping the fabric between the male and female elements and the frictional resistance of the engagement is sufficient to hold the two elements together to form a lath and to connect the lath to the fabric. Not stitching or sewing is required and, in fact, the edge of the fabric may be left as a ra wedge since no risk of fraying will arise due to the fact that the edge of the fabric is totally enclosed wihin the lath and pressed in such a way that no movement of the edge can take place to cause fraying.

Preferably the said male and female parts of the elements are respectively an elongate ridge extending the length of the element and an elongate groove of corresponding size (that is, slightly larder, to accommodate the thickness of the fabric) also extending the length of the element and spaced transversely of the element from the ridge by the same distance as the ridge from a longi- tudinal median line of the element. By such a constrflction the two cooperating elements forming a blind bottom lath can be identicall, it not being necessary to provide cooperating left and right handed parts. Alternatively, however, the- said male and female parts may comprise a plurality of studs and cooperating bosses having appropriatdy di melxsioned sockets, in- positions which correspond to those of the studs when the element is inverted so thát cooperating engagemeat can be effected. This embodiment is slightly less easy to use than the embodiment in which the male and female elements are elongate ridges and channels in that it is necessary to adjust the longitudinal positions of two elements to be engaged in order to align the cooperating bosses and studs.

The relative size of the male and female parts must be such that a layer of fabric can be trapped between them without deforming the part unduly, and therefore the groove is preferably somewhat larger than the ridge. If the groove and ridge both have substantially parallel sides then engagement between them relies on friction between the fabric and the material of which the element is made, which is preferably a plastics material, at the pressure exerted by the sides of the groove which are forced outwardly upon insertion of the ridge with the fabric layer interposed between them.

In a preferred embodiment, however, the sides of the said elongate groove and ridge are undercut so that the two elements snap engage one another when a layer of fabric is interposed between them, the dimensions being such that two elements placed in juxtaposition would hold together even if there is no suitable layer of fabric between the male and female parts.

Elements formed as embodiments of the present invention are also preferably shaped to as to provide, with a cooperating like such element, clamping engagement for a pull cord which extends laterally from a blind bottom lath formed by the two said elements in a direction away from the fabric trapped between the two elements. The elements may be so shaped that the face thereof opposite that bearing the grooves and ridges is entirely smooth, or alternatively it may be patterned with a surface texture of any desired form; the lateral sides of the element are preferably so shaped that when two such elements are fitted together with a layer of fabric between at least one pair of cooperating male and female parts, the edges substantially coincide, so that the exterior surface. of the lath formed by two such elements has an approximately rectangular cross-section.

The present invention also comprehends a blind bottom lath comprising two elements as defined herein clamped together, and also a roller blind having a blind bottom lath herein attached to one edge of the fabric of the blind.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a short section of moulding from which one element according to the - present invention may be formed; Figure 1A is an enlarged detail of part of Figure 1; and Figure 2 is a perspective view illustrating two blind bottom laths clamped together and to ..one edge of a sheet of fabric.

Referring now to the drawings the element shown in Figure 1 is generally indicated 11 and comprises a substantially flat basal part 12 having two upstanding lateral side flanges 13, 14. Spaced inwardly from the edge 14 is an upstanding ridge 15 in the form of a generally planar web 15a having, along the free edge, an enlarged portion 15b.

Spaced from the opposite lateral flange 13 by the same distance as the ridge 15 is spaced from the lateral flange 14, are two smaller ridges 16, 17 which define between them an elongate groove 18 which extends parallel to the length of the element 11.

The ridges 16, 17 are' curved in crosssection and'the face of each ridge 16, 17 which faces the other is provided with an overhanging lip 16a, 17a respectively which can be seen in greater detail in the enlarged insert Figure 1A which is an enlarged scale.

The curvature of the ridges 16, 17 provided them with an appropriate degree of resilience and the overhanging lip 16a, 17a define undercut regions 16h, 17b.

Figure 2 illustrates a blind bottom lath, generally indicated 20 formed by fitting together two elements such as that shown in Figure 1. Like reference numerals are used to indicate the corresponding components in both elements, but the reference numerals identifying one of the elements are pro..

vided with primes for identification purposes. As can be seen from Figure 2, the two ridges 15, 15', are engaged into the grooves 18, 18', defined by the two sets of smaller ridges 16, 17 and 16', 17'. The ridge 15 and the ridges 16', 17' trap between them a sheet of fabric 21 along the bottom edge thereof, the fabric 21 forming part of a roller blind on a roller (not shown).

The ridge 151 on the element 11' and the cooperating ridges 16, 17 on the other element 11 also engage although the engagement between these components is not so firm since no fabric extends between - them.

It would be possible, of course, to position the fabric 21 so that it was engaged between both sets of 'male and female parts.

The lateral flanges 13, 14, and 13', 14' are, as will be seen from Figure 2, do dimensioned with relation to the height of the ridge 15, that cooperating flanges 13, 14' and 13', 14 just meet with sufficient clearance to permit the fabric 21 to pass between them. These flanges can also be used, as can be seen from Figure 2, to provide engagement for a pull cord 22 which, in order to fit it to the lath 20, merely requires to be knotted at its upper end, the knot is then trapped by the lateral flanges 13, 14' within the interior of the lath between the ridge 15' and the lateral flanges 13, 14'. The pull cord 22 in such an embodiment is free to slide along the length of the lath, but if this is considered to be a disadvantage transverse webs between the flange 13, 14 and the adjacent ridges 15, 17 may be provided at intervals along the length of the element 11 to restrict the longitudinal movement of the pull cord 22.

As will be seen from the above description attachment of a blind bottom lath to the edge of a sheet of fabric forming part of a roller blind is extremely quick and simple requiring no preparation of the fabric and thereby reducing the labour involved in this operation. Lined bottom laths formed as embodiments of the present invention also have an aesthetic effect of their own and can be provided with appropriate patterning or surface texture for this purpose.

In order to facilitate positioning the fabric 21 on the element 11 prior to fitting the element 11', a strip of double-sided adhesive tape may be positioned between the ridge 15 and the ridge 16: the fabric 21 is then layed over the element 11 and the edge pressed down to contact the adhesive tape which then holds it in position while the second element 11' is clipped into place.

End caps (not shown in the drawing) may also be provided to close the ends of the lath 20 when the two elements 11, 11' have been-snap-engaged together. Such end caps may have resilient members for snapengaging within the lath 20, or may be designed to be a push-fit, perhaps flexing the flanges 13, 14 outwardly as they are inserted.

WHAT WE CLAIM IS:- 1. An element for forming, together with a like such element a blind bottom lath, comprising a strip of moulding the cross sectional shape of which includes respective male and female parts dimensioned such as to cooperate with opposite such parts on the said like such element to trap a layer of fabric between the elements whereby to hold a composite lath, comprising two such elements, together and to the fabric.

2. An element as claimed in Claim 1, in which the said male and female parts are respectively an elongate ridge extending the length of the element and an elongate groove of corresponding size also extending the length of the element and spaced transversely of the element from the ridge by the same distance as the ridge from a longitudinal median plane of the element.

3. An element as claimed in Claim 2, in which the sides of the said elongate groove and ridge are undercut so that the two elements snap engage with one another when a layer of fabric is interposed between them.

4. An element as claimed in any of Claims 1 to 3, which is shaped to provide, with a cooperating element clamping engagement for a pull cord which extends laterally from a blind bottom lath formed by two such elements in a direction opposite that of the said fabric trapped between the two elements.

5. An element as claimed in any preceding claim, in which the face of the element opposite that face which carries the said cooperating parts is smooth and so formed that two such elements fit together with their edges substantially coincident so that the exterior surface has an approximately rectangular cross section.

6. An element for forming, together with a like such element, a blind bottom lath, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

7. A blind bottom lath comprising two elements as claimed in any of Claims 1 to 6 fitted together.

8. A blind having a blind bottom lath as claimed in Claim 7.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. then trapped by the lateral flanges 13, 14' within the interior of the lath between the ridge 15' and the lateral flanges 13, 14'. The pull cord 22 in such an embodiment is free to slide along the length of the lath, but if this is considered to be a disadvantage transverse webs between the flange 13, 14 and the adjacent ridges 15, 17 may be provided at intervals along the length of the element 11 to restrict the longitudinal movement of the pull cord 22. As will be seen from the above description attachment of a blind bottom lath to the edge of a sheet of fabric forming part of a roller blind is extremely quick and simple requiring no preparation of the fabric and thereby reducing the labour involved in this operation. Lined bottom laths formed as embodiments of the present invention also have an aesthetic effect of their own and can be provided with appropriate patterning or surface texture for this purpose. In order to facilitate positioning the fabric 21 on the element 11 prior to fitting the element 11', a strip of double-sided adhesive tape may be positioned between the ridge 15 and the ridge 16: the fabric 21 is then layed over the element 11 and the edge pressed down to contact the adhesive tape which then holds it in position while the second element 11' is clipped into place. End caps (not shown in the drawing) may also be provided to close the ends of the lath 20 when the two elements 11, 11' have been-snap-engaged together. Such end caps may have resilient members for snapengaging within the lath 20, or may be designed to be a push-fit, perhaps flexing the flanges 13, 14 outwardly as they are inserted. WHAT WE CLAIM IS:-

1. An element for forming, together with a like such element a blind bottom lath, comprising a strip of moulding the cross sectional shape of which includes respective male and female parts dimensioned such as to cooperate with opposite such parts on the said like such element to trap a layer of fabric between the elements whereby to hold a composite lath, comprising two such elements, together and to the fabric.

2. An element as claimed in Claim 1, in which the said male and female parts are respectively an elongate ridge extending the length of the element and an elongate groove of corresponding size also extending the length of the element and spaced transversely of the element from the ridge by the same distance as the ridge from a longitudinal median plane of the element.

3. An element as claimed in Claim 2, in which the sides of the said elongate groove and ridge are undercut so that the two elements snap engage with one another when a layer of fabric is interposed between them.

4. An element as claimed in any of Claims 1 to 3, which is shaped to provide, with a cooperating element clamping engagement for a pull cord which extends laterally from a blind bottom lath formed by two such elements in a direction opposite that of the said fabric trapped between the two elements.

5. An element as claimed in any preceding claim, in which the face of the element opposite that face which carries the said cooperating parts is smooth and so formed that two such elements fit together with their edges substantially coincident so that the exterior surface has an approximately rectangular cross section.

6. An element for forming, together with a like such element, a blind bottom lath, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

7. A blind bottom lath comprising two elements as claimed in any of Claims 1 to 6 fitted together.

8. A blind having a blind bottom lath as claimed in Claim 7.