VENETIAN BLINDS AND METHOD OF MANUFACTURE

Abstract: The specification discloses a method of assembling two different venetian blinds having two different slat widths, the flexible elements 14, 16 of a ladder means of which are each mounted on a tilt roll 10, the flexible element of each pair extending down the different opposite lateral outermost points 18, 20 of the tilt roll 10. Identical tilt rolls are utilized for the ladder means of the blinds of first and second widths. The flexible elements of each ladder means of the blind of slats of lesser width are attached to the respective tilt rolls 10 (Figure 1A), so that they extend directly from the securing means 12 of the tilt roll to the laterally outermost points 18, 20 of the roll 10. The flexible elements of each ladder means for the blind with the slats of greater width are attached to the respective tilt roll 10 , so that each of the flexible elements 14, 16 of each pair extends from the securing means 12 of the tilt roll 10 around at least half of the periphery of that tilt roll to reach the laterally outermost points 18, 20 of that roll when the blind is in its fully opened position. Thus the tilt roll must be rotated a greater distance for the blind of greater slat width than for that of the lesser slat width to give a given angle of tilt.

Description: The present invention relates to venetian blinds. Conventionally a venetian blind comprises a headrail, at least two ladder means, each having a pair of spaced, longitudinally extending, flexible elements and spaced rungs interconnecting said elements, slats supported by said rungs, a tilt roll associated with said ladder means, connecting means on said tilt roll for connecting the tilt roll to each of the flexible elements of the associated ladder means and means to rotate the tilt rolls, to effect tilting of the slats to any position from and between one fully closed position, via a fully open position, to a second fully closed position. It has been proposed, over the years, to provide venetian blinds having slats of different widths. For horizontal inside blinds it is conventional to have slats of 50 mm width, 25 mm width, 16 mm width and even smaller. It has been conventional to provide a headrail usually of substantially the same width as the slat material, for blinds of each slat width. These headrails have, as indicated above, usually mounted therein two or more tilt rolls usually associated with a tilt rod and the diameters of these tilt rolls have been different for each different width blind. To manufacture blinds of several different widths, for different requirements, therefore requires a large inventory of components which can be expensive. FR-A-1277291 discloses a venetian blind comprising a headrail, at least two ladder means, each having a pair of spaced, longitudinally extending, flexible elements and spaced rungs interconnecting said elements, slats of a given width supported by said rungs, a tilt roll associated with said ladder means, connecting means on said tilt roll for connecting the tilt roll to each of the flexible elements of the associated ladder means, and means to rotate the tilt rolls to effect tilting of the slats to any position from and between one fully closed position, via a fully open position, to a second fully closed position, the flexible elements of each ladder means each extending around at least half of the periphery of the associated tilt roll, in the fully open position of the blind, to reach said connecting means, the two flexible elements of one ladder means being then wound round that tilt roll in opposite winding senses to extend downwardly from opposite laterally outermost points of the tilt roll. The present invention is characterised in that the diameter of the tilt roll is such, relative to said given width of the slats, that the tilt rolls will be rotated by more than 180° to tilt the blind from the fully open position to either one of the fully closed positions and in that in each said fully closed positions, one of said flexible elements has been fully unwound from its tilt roll whereupon, by continued rotation of its tilt roll, it is transferred to the opposite lateral side to extend substantially vertically downwardly from the roll in close proximity with the associated other flexible element. Such a structure may readily be used for a blind for which the slats are a significantly greater width than the diameter of the tilt rolls. One can, however, use the same headrail and the same tilt roll for a blind having slats of a lesser width but in these latter blinds, the flexible elements will extend directly from the connecting means, on either side of the connecting means, to the opposite laterally outermost points of the tilt roll and then downwardly. With such a structure the tilt roll can be tilted by less than 360° to effect the full tilting motion from the fully open position to either one of the fully closed positions. In this way it is possible to use the same headrail and the same tilt rolls for blinds of two different widths. Thus, according to another aspect of the present invention, there is provided a method of assembling two different venetian blinds which are of first and second slat widths respectively, the second slat width being greater than the first, the venetian blind including at least two ladder means, each having a pair of spaced, longitudinally extending, flexible elements and spaced rungs interconnecting said flexible elements for supporting the venetian blind slats, said pairs of flexible elements each being mounted on a tilt roll and secured thereto by securing means and the flexible elements of each pair extending downwardly from opposite lateral outermost points of its tilt roll, said method comprising utilizing identical tilt rolls for the ladder means of the blinds of the first width and of the second width, on the one hand positioning the pair of flexible elements of each ladder means for the open position of the blind, for the blind with the slats of the first width, and attaching them to the respective tilt rolls so that they extend directly from the securing means which are then located at the top of the tilt roll to the laterally outermost point of that roll when the blind is in the fully opened position and, on the other hand, positioning the pair of flexible elements of each ladder means for the open position of the blind, for the blind with the slats of the second width, and attaching them to the respective tilt roll, so that each of the flexible elements of each pair extends from the securing means which are then located at the bottom of the tilt roll around at least half of the periphery of that tilt roll, to reach the laterally outermost point of that roll, when the blind is in its fully opened position. Headrails of venetian blinds conventionally comprise a channel section member. This channel section member is mounted either with its web uppermost or its web lowermost. With the construction of the invention, if the web is lowermost, then instead of having two apertures, one for each of a pair of spaced longitudinally flexible elements, it is proposed according to the invention that a single elongate slot should be provided to allow the flexible elements to traverse the slot as the tilt roll is rotated because, with the construction and method of the invention, the flexible elements extend from the laterally outermost points of the periphery of that tilt roll at substantially the same location as each other when the blind is in either one of the fully closed positions. The provision of an elongate slot ensures that the top most slat is correctly tilted whereas if one were to have single apertures, one for each flexible element, then there would be a tendency for the top most slat or several slats to be tilted at a different angle from that of the remainder of the blind which does not give a very pleasing aesthetic effect. In order that the present invention may be more readily understood, the following description is given, merely by way of example, reference being made to the accompanying drawings, in which:- Figure 1A, 1B and 1C are schematic views illustrating the tilt roll of a venetian blind of the invention for a slat of the first width, and for a slat of the second width, and also the angles of the slats in different rotational positions of the tilt roll; Figure 2A and 2B illustrate in side elevation schematically two blinds of the invention, one of the first width and one of the second width respectively; and Figures 3 and 4 illustrate a side elevation and an underneath plan respectively of one embodiment of tilt roll of the invention. If reference is first made to the Figure 1, in Figure 1A, there is illustrated a tilt roll 10 having on one portion of its periphery connecting means 12. Longitudinal flexible elements 14, 16 of a ladder means are shown, the element 14 being shown cross-hatched lines and the element 16 in plain double lines. The flexible elements 14, 16 are connected by rungs 15 (Figures 2A and 2B). In the central, 0° position, that is the fully open position (see Figure 1C) the connecting means 12 are shown at the top in Figure 1A and the element 14, 16 are wrapped around one quarter, approximately, of the circumference of the roll to the outermost points 18, 20 of the periphery of the roll. If the roll 10 is rotated by 180° in either direction, then the slats 24 (Figure 1C) will be tilted to approximately their half closed position and if the tilt roll is rotated a further 90°, to the 270° position, then the slats will be tilted to a closed substantially vertical position as indicated at the left and right of Figure 1C. In either one of the fully closed positions one of the flexible elements has been fully unwound from its tilt roll and by further rotation it has been allowed to traverse to the laterally opposite outermost point of the periphery of the tilt roll to extend downwardly therefrom in close proximity to the other flexible element of the same ladder means, the spacing being indicated by arrow 22. If reference is now made to Figure 1B, it will be seen that identical parts have been used and these are referred to in this figure with identical reference numerals. It will be seen that the cord 14 is wrapped around the roll 10 from the point 18 in a clockwise direction to the connecting means 12 which is in this instance at the lowermost position. Similarly the flexible element 16 is wrapped around, from the location 20 in counter-clockwise direction again to arrive at the connecting means 12 at the lowermost position. In each instance, therefore, in the open or 0° position for the blind, the flexible elements 14, 16 are wrapped around, in the opposite wrapping sense, more than one half of the periphery, in fact the greater part of three quarters of the periphery of the tilt roll 10. It will be noted that in order to arrive at the position equivalent to the 180° position of Figure 1A, the tape roll 10 as illustrated in Figure 1B will have to be rotated approximately 270° and to arrive the position equivalent to the 270° position of Figure 1A, the tilt roll 10 will have to be rotated to 450°. In fact in both of the positions illustrated on the left in Figure 1A and Figure 1B, the flexible element 14 extends directly downwardly from the connecting means 12. This is possible with the arrangement of Figure 1B, because the flexible element 14 had been wrapped around the tape roll about three-quarters of a turn (270°). Similar considerations apply to the other extreme position enabling the flexible element 16 to hang directly downwardly from the connecting means 12 on the right-hand side of the drawing. In each instance, therefore, the two connecting elements are directly beside each other in the extreme tilt position as indicated by arrow 22, giving the fully closed position on either side. In order to be able to go from one side to the other, therefore, it is advantageous for the cords to be able to move freely across from one side to the other of the headrail in which the tilt roll is mounted. In Figure 2A and Figure 2B, a headrail 30 is illustrated this having a web 32 and side flanges 34, 36. For the passage of the flexible elements 14, 16, an elongate slot will be provided in the web 32. Alternatively, the headrail could be mounted the other way up, so that it is open at the bottom permitting this traverse of the cords to ensure accurate tilting of the uppermost slat or slats. It will be seen that the same headrail and tilt roll can be used in both Figure 2A and Figure 2B and although the slats 24 are significantly wider in Figure 2B than the they are in Figure 2A. A tilter mechanism 38 of a conventional nature is used to tilt, that is change the angle of the tilt roll 10. In Figures 3 and 4 the tilt roll 10 is shown in somewhat more detail. In particular in Figure 3 it is shown how the connecting means 12 extend from a sleeve 40 which surrounds a shaft like element 42. In Figure 4 it can be seen that the shaft like element 42 is provided with a key structure 44 radially protruding from its periphery. The key structure 44 extends in the axial direction of the shaft like element 40 and has progressively slanted sides towards an enlarged middle portion 46. In this manner the shaft like element 42 can be economically produced as a moulding, whereas the connecting means 12 can be formed integrally with the sheet metal sleeve 40. The sleeve 40 being provided with a longitudinal slit conforming to the shape of the key structure 44 and having rounded edges 48 can be snap-fitted onto the shaft like element 42 and will be held in position by the enlarged portion 46.

Claims: A method of assembling two different venetian blinds which are of first and second slat widths respectively (Figures 2A and 2B), the second slat width being greater than the first, the venetian blind including at least two ladder means, each having a pair of spaced, longitudinally extending, flexible elements (14,16) and spaced rungs (15) interconnecting said flexible elements (14,16) for supporting the venetian blind slats (24), said pairs of flexible elements each being mounted on a tilt roll (10) and secured thereto by securing means (12) and the flexible elements of each pair extending downwardly from opposite lateral outermost points (18, 20) of its tilt roll (10), said method comprising utilizing identical tilt rolls (10) for the ladder means of the blinds of the first width (Figure 2A) and of the second width (Figure 2B), on the one hand positioning the pair of flexible elements of each ladder means for the open position of the blind, for the blind with the slats of the first width, and attaching them to the respective tilt rolls (10) so that they extend directly from the securing means (12) which are then located at the top of the tilt roll to the laterally outermost point (18, 20) of that roll (see Figure 1A) when the blind is in the fully opened position and, on the other hand, positioning the pair of flexible elements of each ladder means for the open position of the blind, for the blind with the slats of the second width (Figure 2B), and attaching them to the respective tilt roll (10), so that each of the flexible elements (14,16) of each pair extends from the securing means which are then located at the bottom of the tilt roll around at least half of the periphery of that tilt roll, to reach the laterally , outermost point (18,20) of that roll (see Figure 1B), when the blind is in its fully opened position. A venetian blind comprising a headrail (30), at least two ladder means, each having a pair of spaced, longitudinally extending, flexible elements (14,16) and spaced rungs (15) interconnecting said elements, slats (24) of a given width supported by said rungs, a tilt roll (10) associated with said ladder means, connecting means (12) on said tilt roll for connecting the tilt roll to each of the flexible elements (14,16) of the associated ladder means, and means (38) to rotate the tilt rolls to effect tilting of the slats to any position from and between one fully closed position, via a fully open position, to a second fully closed position, the flexible elements (14,16) of each ladder means each extending around at least half of the periphery of the associated tilt roll, in the fully open position of the blind, to reach said connecting means (12), the two flexible elements (14,16) of one ladder means being then wound round that tilt roll in opposite winding senses to extend downwardly from opposite laterally outermost points (18,20) of the tilt roll, characterised in that the diameter of the tilt roll is such, relative to said given width of the slats, that the tilt rolls will be rotated by more than 180° to tilt the blind from the fully open position to either one of the fully closed positions and in that in each said fully closed positions, one of said flexible elements (14,16) has been fully unwound from its tilt roll (10) whereupon, by continued rotation of its tilt roll, it is transferred to the opposite lateral side to extend substantially vertically downwardly from the roll in close proximity (spacing 22) with the associated other flexible element. A blind according to claim 2, characterised in that the connecting means (12) of said tilt roll (10) are located at the bottom of the tilt roll when the blind is in the fully open position. A blind according to claim 2 or 3, characterised in that the headrail (30) is of channel cross-section, with the web (32) of the channel at the lower part, and in that elongate slots are formed in said web for the passage of said flexible elements and their transfer from one lateral side in said one fully closed position to the opposite lateral side in said second fully closed position.

Inventors: VAN DER ZANDEN, GEORGE CHRISTIAAN
Applicants: HUNTER DOUGLAS INDUSTRIES B.V.
Application year: 1990
Main classification: E06B9
IPC codes: E06B9