IE43239B1 - Window roller blind assembly - Google Patents

Abstract

A window shade apparatus which may be customized to a selected width within a predetermined range by the ultimate user without the use of tools at the point of use, which includes a two-piece telescopically adjustable shade roller, and a sheet of flexible, web like shade material, the width of which can be substantially conformed to the adjusted length of the shade roller, by separating a marginal side portion of the shade material from the balance of the shade material, along a selected one of a plurality of pre-cut lines of weakness, the lines of weakness being relatively imperceptible by the unaided human eye when viewed at a reasonable distance. A bottom window shade slat assembly, continuously adjustable within a predetermined range, and an enclosed, substantially dust-free releasable automatic locking device for the shade roller, utilizing a ratchet and counter-balanced and centrifugally actuated pawls, are also disclosed.

Description

This invention relates to a window roller blind assemblyintended for adjustment and fitting at the time of installation by the ultimate user.

Retractable window blinds (generally called roller blinds nowadays) have been well known for many years. To provide a proper fit for the blinds for windows of various widths, it is necessary to adjust the width of the entire blind assembly. A roller blind assembly customarily consists of a sheet of vinyl or other flexible material, a roller to which the sheet of material is attached, a spring-driven motor for driving the roller, and a light-weight slat inserted in a seam along the bottom edge of the blind material to provide rigidity. The sheet has to be severed to facilitate fitting of the blind to a window, and the rollers and bottom slats must be cut by a saw or like tool. Furthermore, the lower edge of the material, which is folded over and seamed to house the bottom slat, must be cut at the seam by a knife or similar device.

In addition, window blind locking devices have usually included gravity-actuated pawls pivoted about an axis parallel to the blind roller axis and engageable with a notched cam or ratchet member. Such devices of necessity have had to be relatively large in order to accommodate the pawls pivoting about axes a substantial distance removed from the axis of the roller and the ratchet member. In addition, the pawls, pivots and ratchet had to be manufactured to close tolerances in order to fi.t into the limited space provided. 3239 - 3 Xt has also been proposed to use a locking device comprising a pair of matched members having elongate slots extending in a direction parallel to the axis of rotation and free floating pins having curved sections inserted in holes extending in a direction transverse to the direction to the axis of rotation. Such an arrangement has the disadvantage that the relatively light-weight pins, which are moved by the application of gravitational and centrifugal forces, do not necessarily engage or disengage the notched member at the desired time.

With these considerations in mind, an aim of the present invention is to provide a window roller blind assembly which is readily adjustable in width without the use of tools. A subsidiary aim. Which does not necessarily apply to all constructions in accordance with the invention, is to provide a smoothlyoperating releasable automatic locking device for use with a window blind roller.

According to the present invention, a window roller blind assembly intended for adjustment (without tools) and fitting at the time of installation by the ultimate user comprises a sheet of flexible material having a line of weakness (or a plurality of generally parallel lines of weakness) extending from the top portion to the bottom portion of the sheet to permit a part of th< sheet to be torn off, the line or lines of weakness being so ormed that, upon tearing of the sheet material along the lini or one of the lines of weakness to reduce the width of the sheet material to a width desired by the user, a clean, strc ight edge is formed, the line, or each of the lines of weaknes: , comprising a continuous cut or slit which penetrates into the sheet material by only a portion of the thickness of the sheet material, and a telescoping roller assembly onto which and off which the sheet material can be rolled and unrolled 9 - 4 respectively, the roller assembly including a first roller section into which a second roller section slidingly extends in telescopic fashion so as to permit the overall length of the roller assembly to be shortened in order that it may correspond to the desired width of the sheet material, the sheet material having a part of its top portion attached to the first roller section, and the roller assembly having means for so retairing another part of the top portion of the sheet material that, it is prevented from coming away from the second roller section during use of the roller blind assembly.

The window roller blind assembly described above can comprise a bottom slat assembly carried by the bottom portion of the sheet material, the bottom slat assembly being adjustable so that its length can be matched to the length of the telescoping roller assembly and the desired width of the sheet material.

The first roller section preferably has a substantially constant external diameter from end portion to end portion and has the said part of the top portion of the blind secured to it, the outer end portion of the first roller section having first means for supporting the window blind assembly from a first support location, and the inner end portion of the first roller section having an opening therein of a size to receive the second roller section which also has a substantially constant external diameter from end portion to end portion. The assembly further comprises means for precluding relative rotation between the first and second roller sections, the said other part of the top portion of the blind being held stationary with respect to the second roller section along the whole length of that part of the second roller section which projects from the inner end of the first roller section so that the positions 3 2 3 9 - 5 of the first and second roller sections are fixed with respect to one another and to the blind throughout the entire area of overlap of the blind and the roller assembly.

In the production assembly of one form of window roller blind assembly in accordance with the invention, the roller, with a pair of support adaptors installed at its ends, is extended to the full length of the blind material, as is the extendable bottom slat. An adhesive substance is applied to the outside surface, in the longitudinal direction, of both sections of the telescoping roller. The adhesive surface on the outside surface of the smaller-diameter second section, however, is covered with an overlay of paper or other suitable protective material. When the blind is initially attached to the roller, it is attached only along the adhesive surface on the larger-diameter first section of the telescoping roller.

The above-mentioned line or lines of weakness can comprise one or more cut lines in which the depth of cut from one end of the blind to a location adjacent the other end of the blind is less than the thickness of the blind. The cut lines can extend completely through the thickness of the blind at one end portion of the blind to provide a plurality of individual tabs which may be manually grasped and pulled for the purpose of severance of a side portion of the blind. The tabs are preferably formed at the upper end of the blind.

The adhesive substance carried by the second roller section preferably commences at the outer end portion thereof and extends inwardly for substantially the entire length of the second roller section when it is extended to its maximum length with respect to the first roller section. The temporary protective material overlying the adhesive substance is removable by hand from contact with the adhesive substance throughout that - 6 portion of the length of the second roller section which extends beyond the inner end of the first roller section, so that the adhesive substance may remain protected until just prior to secur ement of the said other part of the top portion of the blind to the roller assembly.

There may be a slat pocket at the lower end of the blind, the slat pocket being formed by doubling the lower end of the blind upon itself. The doubled back portion is secured to the main drop of the blind at discrete securement locations, the securement locations in that part of the blind having the line or lines of weakness being located between the lines of weakness, or between the line or weakness and -She closest adjacent side edge of the blind, so that severance of a side portion of the blind along a line or weakness will not intersect a securement location.

The slat assembly may include a first section formed from wood of a length no greater than the width of that part or the blind which contains no lines of weakness, and at least one second section which is carried by the first section and is telescopically adjustable with respect to the first section, thereby allowing the overall length of the slat assembly to be adjusted by hand to a desired length which conforms to the final width of the blind. The second section of the slat assembly may be secured to the first section of the slat means assembly by a friction fit.

The outer end portion of each of the telescoping roller sections is preferably hollow and has a window blind support adaptor inserted in it, each of the adaptors comprising a cylindrical body having a diameter smaller than the inside dieimeter of its associated roller section and with a plurality of longitudinally-extending ribs extending along the outer sur43239 - 7 fac” of the cylindrical body. There may be releasable automatic locking means for use with a spring in the roller assembly for rolling up the blind on the roller, the locking means comprising two matched members adapted to be fitted together to form a cylindrically-shaped member which, in one, is positioned inside a hollow end portion of one of the roller sections and is inter-engaged with the roller, the said member being provided with a first recess to form a cylindrical bore extending coaxially with the axis of rotation of the roller and a second recess extending in a direction radially outwardly from the axis and continuing in a direction parallel to the axis. There are also a pair of pins extending across the second recess in a direction perpendicular to the axis, a pair of substantially flat, elongate plates pivotally mounted on the pins, and a cylinder disposed in the bore and having a toothed wheel at one end thereof. The elongate plates are disposed for cooperative engagement with the wheel by the application of gravitational force, and disengageable from the wheel during rotation of the roller by the application of centrifugal force. Each of the matched members may be provided with a semi-circularly-shaped recess adapted to receive the wheel, the matched members each having an end panel at one end adapted to form an end panel for the roller when the said members are inserted in the hollow end section of the roller. The elongate plates may be counterbalanced by being pivoted at a point removed from the longitudinal extremities thereof.

The cylindrically-shaped member may comprise means at one end thereof adapted for non-rotational engagement with a fixed mounting arrangement external to the roller.

By means of the present invention, the installation of a new window roller blind is reduced to a few simple steps which may be carried out without the need of tools. A standard size 43230 - 8 window roller blind made in accordance with the invention maybe marked to the desired width by holding the blind in front of the window to be fitted. The smaller diameter second section of the telescoping roller is then pushed in until the length of the telescoping roller coincides with the desired width of the blind. The blind may then be unrolled and a strip of the window blind material corresponding to the excess w dth torn along the tear line most nearly corresponding to the outer edge of the newly-positioned second section of the telescoping roller. Tha excess material is torn along the full length of the tear line and after the bottom slat is adjusted to the desired width, the entire excess strip of material may be removed. The protective cover is then removed from the adhesive material on that portion of the smaller-diameter second section of the telescoping roller which extends beyond the larger-diameter first section. The portion of the material overlappping the newly exposed adhesive is simply pressed down and the blind rolled up. When the extendable bottom slat has been adjusted to the desired length, the blind is ready for hanging.

Some examples of window roller blinds in accordance with the invention are shown in the accompanying drawings, in which: Figure 1 is a perspective view of one form of window roller blind in accordance with the invention; Figure 2 is a cross-section through one section of the telescoping roller taken along the line 2-2 in Figure 1; Figure 3 is a cross-section through a second section of the telescoping roller taken along the line 3-3 in Figure 1; Figure 4 is a front view of the adjustable bottom slat; Figure 5 is a cross-section of the bottom slat taken - 9 along line 5-5 in Figure 4; Figure 6 is an exploded perspective view of the end pin and adaptor; Figure 7 is a perspective view of the blind motor and motor adaptor; Figure 8 is a front view of the blind motor adaptor; Figure 9 is a cross-section of the motor adaptor taken along the line 9-9 in Figure 8; Figure 10 is a front view of the end pin adaptor,Figure 11 is a sectional view of the end pin adaptor taken along the line 11-11 in Figure 10; Figure 12 is an exploded perspective view of an alternative blind motor assembly; Figure 13 is a side view of a roller blind assembly showing the blind motor assembly and spring attachments with the telescopic positions cut away; Figure 14 shows a section taken along the line 14-14 in Figure 13; Figure 15 shows a section taken along the line 15-15 in Figure 14; and Figure 16 shows a section taken along the line 16-16 in Figure 15.

The roller blind assembly shown in Figure 1 comprises a sheet of vinyl material 101 having a plurality of tear lines 110 parallel to one side edge of the material. The thickness of the material may lie in the conventional range of from about 41/2 thousandth's of an inch to about 12 thousandth’s of an inch.

Such tear lines can be formed by weakening the material along these lines. This may be done, for example, by cutting or 130 - 10 otherwise making slits in the material without penetrating the material. The upper end portion 111 of each of the tear lines is here cut right through or deeply scored to facilitate the tearing of the material along the tear lines. In this illustrative embodiment of the invention, the blind 101 is attached to a larger-diameter section 120 of a telescoping roller by means of an adhesive area 121 on that section. An adhesive area 123 is also provided on the outer surface of a smaller-diameter section 122 of the telescoping roller. However, the area-. 123 is covered with a paper overlay 124 or similar protective material and remains covered until the blind has been adjusted to the desired width, as will be explained later.

Si ch adhesive material for the strips 121 and 123, which will ac here to the blind material, is readily available commercially.

Further, as shown in Figure 1, the lower portion of the blind material is folded over to form a pocket 103. A seam is made along the upper edge of the pocket. Such a seam may be made, for example, by heat or Ultrasonic sealing techniques.

In order to facilitate removal of a strip of material torn along one of the tear lines 110, the seam is formed in accordance with a specified pattern producing an interrupted seam comprising several individual sections 112 separated by sufficient distance to avoid overlap of any of the tear lines.

Figure 4 shows an extendable bottom slat for use with the window blinds such as may be inserted in the pocket 103. The extendable slat consists of three sections: two outer sections 401 and 402 which are substantially identical and which can be made of a light-weight material such as a rigid synthetic plastics or metal; and a centre section 403, which may be made, for example, of light-weight wood or similar «aterial. The dimensions of the centre section 403 are so chosen that this 3 2 3 9 - 11 section will fit snugly within sections 401 and 402 as shown in Figure 5. Figure 5 is a cross-section taken along the line 5-5 in Figure 4 to show the general construction of the external sections 401 and 402 and the centre portion 403.

As mentioned already, the roller of the blind assembly comprises two telescoping sections. A cross-section of the larger-diameter section 120 is shown in Figure 2. This section comprises a hollow tube having a fold-over seam 201 extending inwardly of the tube in such a manner that the external surface of the tube is substantially smooth and the inner surface of the tube is provided with a protrusion having a substantially rectangular-shaped cross-section of a specified width and th ickne.u.'i. Figure 3 shows a cross-section of the smal Ler dinmoter section 122 of the telescoping roller which likewise comprises a hollow provided with a seam 301 similar to the seam 201 of the tubular section 120. Additionally, the tubular section 122 is provided with a recess 302 having a substantially rectangular cross-section and having dimensions slightly greater than the rectangular cross-section of the seam 201 of the section 120. When the two telescoping sections 120 and 122 i are brought together, the seam 201 will be aligned with the recess 302 and, when the section 122 is slideably engaged with the section 120, the seam 201 and the recess 302 cooperate to provide an interlock between the two sections to prevent rotation of one section with respect to the other.

Figure 7 shows a blind motor adaptor 701 and a spring driven blind motor which provides the necessary power to retract the blind by winding it onto the roller. Figure 8 represents a front view of the motor adaptor and Figure 9 shows a cross-section of the motor adaptor taken along the line 9-9 in Figure 8. The adaptor, which can be made of a synthetic 2 3 9 - 12 plastics or the like material, is inserted in tie accessible end opening 126 of the larger-diameter section 120 of the telescoping roller. The adaptor is provided with several riblike protrusions 703 having a slanted or bevelled forward section 704. The diameter DI indicated in Figure 8 is selected to be slightly less than the inside diameter of the tubular section 120 to allow for a snug fit of the adaptor inside the tube. The slanted or bevelled forward sections 704 are provided to facilitate entry into the accessible end opening 126. The distance between adjacent ribbed sections 703 is selected to be sufficiently great to accommodate the seam 201. When inserted properly, the adaptor 701 will form an interlock with the seam 201 to prevent the rotation of the adaptor with respect to the tubular section 120, The retractor motor is fitted in the recess 901 of the adaptor 701.

Figure 6 shows an end pin adaptor 1001 and an end pin 1002. End pins similar to the one shown in Figure 6 are well known. The adaptor 1001 has a general external shape similar to that of the motor adaptor 701. A front view of the end pin adaptor is shown in Figure 10 and a cross-section taken along the line 11-11 of Figure 10 is shown in Figure 11. The end pin adaptor is inserted in the accessible end 128 of the smaller-diameter section 122 of the telescoping roller. The outside diameter D2 indicated in Figure lo is slightly less than the inside diameter of the section 122 to allow for a snug fit in the tubular end section. The distance between the ribbed sections 1003 is so chosen that the seam 301 and the recess 302 of the tubular section 122 will fit between adjacent ribbed sections, thereby providing a rotational interlock between the adaptor 1001 and the tubular section 122.

The end pin 1002 is inserted ih the centre opening 1005 of the - 13 adaptor 1001.

Figure 12 shows an alternative blind motor assembly having two half sections 511 and 512 each provided with a semi-circular bore which permits the insertion of a cylinder 513 when the two half sections are joined. One of the half sections, 511, is provided with pegs or dowels 514 extending from the surfaces 515 of the half section 511. The half section 512 is provided with corresponding surfaces 515 and with matching holes 516 corresponding to the pegs 514 in position on the surfaces 515, and adapted to receive the pegs 514 (see Figures 14 and 16). The purpose of the pegs is to align the two half sections and to provide pivotal supports for the pawls 517. Since the surfaces 515 of both half sections 511 and 512 are recessed, a space is provided when the two half sections are snapped together to allow for the insertion of pawls 517, as shown for example in Figure 16. The pawls 517 comprise substantially flat, elongate plates as shown in Figure 12. The pawls 517 are pivotally mounted on the pegs 514 and are movable in a direction extending radially outwards from the axis of rotation.

The cylinder 513 is provided with an opening 523 (Figures 14 and 15) for non-rotatable engagement with one end of the rod 518. The spring 519 is adapted to be attached to the rod 518 at slot 534 shown in Figure 13. The other end of the spring 519 is attached to one of the halt sections 511 or 512 as discussed later herein. The cylinder 513 is further provided with a flat portion 521 adapted to fit non-rotatably in a window blind support bracket (not shown). The half sections, when snapped together, are adapted to fit snugly inside the window blind roller 535, and are fixedly engaged with the inner surface of the roller 535 by means of ribbed sections on the inner surface of the roller (not shown). - 14 43239 One or both of the half sections 511 and 512 are provided with a substantially rectangularly-shaped projection 540 near the spring end of the outer surface of the housing. The spring 519 is provided at one end thereof with a member 537 having a substantially rectangularly-shaped opening which is adapted to fit over the shoulder section 540 as shown in Figure 13. When assembled, the spring 519, the rod 518, the cylinder 513, the pawls 517, and half sections 5ll and 512 together form an independent unit which may be readily inserted into a window blind roller.

In the completed blind assembly, the motor adaptor 701 together with the motor 702 and the end pin adaptor 1001 together with the end pin 1002 will be inserted in the openings 126 and 128, respectively, of the telescoping roller. The telescoping roller will be extended to a length corresponding to the total width of the blind material 101, and part of the upper section of the latter will be attached to the adhesive area 121 of the outer tubular section 120. The bottom slat (Figure 4) will be inserted in the slat pocket 103 and extended to the full width of the blind naterial 101. In installing the blind, the desired width of the blind may be determined and the blind may be torn along one of the tear lines 110 to obtain the desired width of the blind. After the bottom slat (Figure 4) is removed or moved to one side, the blind nay be torn along its full length without the use of any tools. An additional step in preparing the blind for mounting is to push the smallerdiameter roller section 122 into the larger-diameter roller section 120 until the total length of the telescoping roller assembly corresponds to the width Of the window. Thereafter, io the overlay 124 is removed from that portion of the adhesive area 123 which is not covered by the telescoping section 120. .5 3 2 3 9 - 15 The upper portion of the blind material 101 which overlaps the newly exposed adhesive area 123, is then attached thereto. The bottom slat is also reinserted and adjusted to a length corresponding to the new width of the shade by sliding the end sections 401 and 402 towards each other.

After the window blind 536 is installed and rolled down, the portion of the spring attached to one of the half sections at 540 will rotate with the blind roller while the other end of the spring will remain fixed in its original position by virtue of its attachment to the rod 518 at 534. Whan the blind is rolled down, the roller 535 and the snapped together half sections 511 and’512 engage'd-thereto will be rotated in the counter clockwise direction, and, if the blind has been properly installed, the end piece 521 of the cylinder 513 will be engaged with a stationary window support bracket (not shown). Consequently, the ratchet wheel 522 will remain stationary when the roller 530, the half sections 511 and 512, and the pawls 517 revolve around the axis of the roller. As is apparent from the drawing, the ratchet wheel 522 is designed to allow free rotation of the roller in the counter-clockwise direction, allowing the blind to be rolled down. During rotation of the roller, centrifugal force will tend to hold the pawls 517 away from the ratchet wh> el 522. When rotation is stopped, one of the pawls will engage with the ratchet wheel due to gravitational force. A clockwise rotational force will be exerted by the spring 519 ho ding the pawl against the teeth of the ratchet wheel 522.

Wh n the blind is to be aised any distance, the blind is first rolled down in the counter-clockwise direction and then released to be raised by means of the rotational force of the spring exerted in the clockwise direction. Advantageously the pawls 517 are so counter balanced that a relatively small 239 rotational spaed will provide sufficient centrifugal force to hold the end portions 517a away from the ratchet wheel 522.

The counter balance aids in releasing the ends 517a of the pawls from the ratchet wheel 522 and provides for smoother operation of the roller shade. Due to the counter balance of the pawls 517, a larger number of stopped positions are available for the roller blind. The ratchet wheel 522 shown in Figure 16, has six teeth. Customarily, roller blind motors relying on centrifugal force to hold the pawls away from the ratchet wheel generally have only two or four stopping positions, since non-counter balanced pawls require a substantially greater rotational speed to be held away from the ratchet wheel and a larger surface without teeth or notches has to be provided on the ratchet wheel.

The two half sections 511 and 512 each have a raised edge 528 and a front cover 524. The edge 528 is designed to fit snugly against the end of a blind roller as shown in Figure 13 and the front surface 524 provides a cover for the motor assembly and for the roller. As is apparent from the drawing, when the two half sections 511 and 512 are fit together, an enclosed unit is formed. The wheel 522 is housed in a recess 525 and the pawls 517 are housed in the recessed surfaces 515, thus substantially reducing the accumulation of dust or lint on the moving parts.

Claims (15)

1. CLAIMS: 1. A window roller blind assembly intended for adjustment (without tools) and fitting at the time of installation by the ultimate user, comprising a sheet of flexible material having a line of weakness (or a plurality of generally parallel lines of weakness) extending from the top portion to the bottom portion of the sheet to permit a part of the sheet to be torn off, the line or lines of weakness being so formed that, upon tearing of the sheet material along the line or one of the lines of weakness to reduce the width of the sheet material to a width desired by the user, a clean, straight edge is formed, the line, or each of the lines of weakness, comprising a continuous cut or slit which penetrates into the sheet material by only a portion of the thickness of the sheet material, and a telescoping roller assembly onto which and off which the sheet material can be rolled and unrolled respectively, the roller assembly including a first roller section into which a second roller section slidingly extends in telescopic fashion so as to permit the overall length of the roller assembly to be shortened in order that it may correspond to the desired width of the sheet material, the sheet material having a part of its top portion attached to the first roller section, and the roller assembly having means for so retaining another part of the top portion of the sh>et material that it is prevented from coming away from the second roller section during use of the roller blind as sembly.

2. A window roller blind assembly according to claim 1, comprising a bottom slat assembly carried by the bottom portion of the sheet material, the bottom slat assembly being adjustable so that its length can be matched to the length of the telescoping roller assembly and the desired width of 4 3 3 3 9 - 18 the sheet material.

3. A window roller blind assembly according to claim 1 or claim 2, in which the first roller section has a substantially constant external diameter from end portion to end portion and has the said part of the top portion of the blind secured to it, the outer end portion of the first roller section having first means for supporting the window blind assembly from a first support location, and the inner end portion of the first roller section having an opening therein of a size to receive the second roller section which also has a substantially constant external diameter from end portion to end portion, the assembly further comprising means for preclud jng relative rotation between the first and second roller sections, the said other part of the top portion of the blind being held stationary with respect to the second roller section along the whole length of that part of the second roller section which projects from the inner end of the first roller section so that the positions of the first and second roller sections are fixed with respect to one another and to the blind throughout the entire area of overlap of the blind and the roller assembly.

4. A window roller blind assembly according to claim 3, in which the cut forming tha line or each line of weakness extends completely through the thickness of the blind at the ιop or bottom portion of the blind to provide a tab or individual tabs which may be manually grasped and pulled for the purpose of severance of a side portion of the blind.

5. A window roller blind assembly according to claim 4, in which the tab or tabs is, or are, formed at the top end of the blind. - 19

6. A window roller blind assembly according to claim 3, in which the means for holding the said other part of the top portion cn’ the blind stationary with respect to the second roller section comprise an adhesive substance carried by the second roller section over an area commencing at the outer end portion thereof and extending inwardly for substantially the entire length of the second roller section when it is extended to its maximum length with respect to the first roller section, the adhesive substance being covered by a temporary protective overlay or other such member which is removable by hand from contact with the adhesive substance throughout that portion of the length of the second roller section which extends beyond the inner end of the first roller section so that the adhesive substance may remain piotected until just prior to securement of the said other p. rt of the top portion of the blind to the roller assembly.

7. A window blind assembly according to any preceding claim, in which the blind is composed of a synthetic plastics material. '

8. A window roller blind assembly according to any preceding claim having a slat pocket at the lower end of the blind which is formed by doubling the lower end of the blind upon itself and securing the doubled-back portion to the main drop of the blind at discrete securement locations, the securement locations in that part of the blind having the line or lines of weakness being located between the lines of weakness or between the line of weakness and the closest adjacent s ile edge of the blind, so that severance of a side portion of tl 3 blind along a line cf weakness will not intersect a st curement location. 4 3 2 3 S - 20

9. A window roller blind assembly according to any one of claims 2 to 8, in which the slat assembly includes a first section formed from wood of a length no greater than the width of that part of the blind which contains no lines of weakness, and at least one second section which is carried by the first section and is telescopically adjustable with respect to the first section so that the overall length of the slat assembly can be adjusted by hand to a desired length which conforms to the final width of the blind.

10. A window roller blind assembly according to claim 9, in which the second section of the slat assembly is secured to the first section of the slat means assembly by a friction fit.

11. A window roller blind assembly according to any preceding claim, in which the outer end portion of each of the telescoping roller sections is hollow and has a window blind support adaptor inserted in it, each of the adaptors comprising a cylindrical body having a diameter smaller than the inside diameter of its associated roller section with a plurality of longitudinally-extending ribs extending along the outer surface of the cylindrical body.

12. A window roller blind assembly according to claim 11 comprising a spring in the roller assembly for rolling up the blind on the roller, and releasable automatic locking means for use with the spring, in which the locking means comprise -two matched members adapted to be fitted together to form a cylindrically-shaped member which, in use, is positioned inside a ho]low end portion' of one of the roller sections and is inter-c ngaged with the roller, the said number being provided vith a first recess to form a ( /lindrical bore extending coaxially with the axis of rota4 3:139 - 21 tion of the roller and a second recess extending in a direction radially outward from the axis and continuing in a direction parallel to that axis, a pair of pins extending across the second recess in a direction perpendicular to the axis, a pair of substantially flat, elongate plates pivotally mounted on the pins, and a cylinder disposed in the bore and having a toothed wheel at one end thereof, the elongate plates being disposed for cooperative engagement with the wheel by the application of gravitational force and disengageable from the wheel during rotation of the roller by the application of centrifugal force.

13. A window roller blind assembly according to claim 12, in which each of the matched members is provided with a semi-circularly-shaped recess adapted to receive the wheel, the matched members each having an end panel at one end thereof adapted to form an end panel for the roller when the members are inserted in the hollow end portion of the roller.

14. A window roller blind assembly according to claim 13, in which the elongate plates are counter-balanced by being pivoted at a point removed from the longitudinal extremities thereof. 15. A window roller blind assembly according to any o e of claims 12 to 14, in which the cylindrically-shaped m iriber comprises means at one end thereof adapted for nonr rational engagement with a fixed mounting arrangement e ;ternal to the roller.

15. A window roller blind assembly intended for adjustment (without tools) and fitting at the time of installation by the ultimate user substantially as described herein with reference to the accompanying drawings.