Venetian blind

Abstract

A venetian blind is provided with the usual plurality of spaced slats. Each slat has opposite outer edge portions which are turned under to provide respective reentrant flanges having free edge portions. Pairs of supporting cords for supporting and adjusting the inclination of these slats are disposed on opposite sides of the slats. Separate securing devices are provided for attaching the slats to the supporting cords with the securing devices being receivable between the slats and the reentrant flanges and having locking parts adapted to engage the respective free edges and outer securing edges of the slats to hold the securing devices in position on the slats.

Description

This invention relates to venetian blinds of the type in which the slats have on their edges turned under flanges and the supporting cords, which support and angularly adjust the slats, are connected to the slats by separate securing devices.

For attachment of the slats by means of the securing devices each supporting cord may have, for example, projecting loops of a strand braided into the cord; those loops are produced at the correct distances apart, i.e. in accordance with the pitch of the slats, when the cord is manufactured. The securing devices hitherto used for connecting the loops of the supporting cords with the slats have been mushroom-shaped plastic knobs which are pushed from below into holes in the slats and which, by their heads, hold the loops in position.

Other securing devices have been proposed, in the form of plastic plates which bridge the slats transversally on the underside. Tongues extending inwards are punched out of these plastic plates near the ends of the latter, one of the loops of the supporting cords being held in each of the tongues.

The known plastic knobs suffer from the disadvantage that they are comparatively loose in the slats, the constant action of the wind on the blind causing the knobs to become worn and eventually to come away from the slats; a further drawback resides in the fact that these knobs are situated a considerable distance away from the edge of the slat, so that the loops of the supporting cords must be made correspondingly long. The result is that the slat cannot be kept sufficiently taut.

The plastic bridging securing devices also suffer from the disadvantage that the slats are guided with little accuracy, as their tongue holding devices are at a considerable distance from the edges of the slats. In addition, the tongue-shaped holding devices open towards the inside and result in a serious risk that under the effect of wind the loops may become unhooked, the entire structure of the blind thus becoming endangered. Furthermore, these bridging elements necessarily have a shape involving excessive expense and labour if they are to embrace the flanged edges of the slats as required.

An object of the invention is to provide a securing device for blinds of the aforementioned type, which will be of simple construction and at the same time enable the slats to be reliably guided by the supporting cords of the blind and to be kept taut, without involving wear.

According to the present invention, a venetian blind comprises a plurality of slats, each having on each edge a turned under flange; pairs of supporting cords for supporting and adjusting the inclination of the slats, the cords of each pair being disposed on opposite sides of the slats; and separate securing devices for attaching the slats to the supporting cords, the securing devices being receivable between the slats and the flanges and having locking parts adapted to engage the slats and hold the securing devices in position on the slats.

The blind according to the invention has the advantage that, on the one hand, the securing devices are firmly connected to the slats, without clearances, so that they cannot rub against each other and cause wear as a result of movements due to wind, etc., while on the other hand the connections between the supporting cords and the securing devices are provided adjacent the edges of the slats; the force and the guiding action of the supporting cords are thus transmitted to the slats in an extremely favourable manner.

Each securing device may be located in an opening in the edge of the associated slat, the locking part locking against the free edge of the flange.

Where the supporting cords are connected by separate securing devices with the respective slat, each securing device may take the form of a substantially U-shaped bracket of which the base is adapted to be attached to the associated supporting cord and each of the legs is formed with a locking part, which may be a barb adapted to lock behind the free edge of the flange.

Alternatively, each securing device may attach both the supporting cords of a pair to a slat, the securing device transversally bridging the slat, and being received between the slats and the respective flanges of the slat.

Each supporting cord may be provided with an auxiliary thread woven in zigzag or turned in and then looped out to form loops for attachment to the slats, and the lay of the auxiliary thread can be increased at certain points along the cord, in order to form a pre-set bending point.

In a further alternative, the cords may be attached to the securing devices by pins each of which extends through one perforation in a supporting cord. In this case the U-shaped bracket may have a fork-shaped head which passes round at least three sides of the relevant supporting cord and to which the pin is affixed.

The invention will be more readily understood by way of example from the following description of venetian blinds in accordance therewith, reference being made to the accompanying drawings, in which:

FIG. 1 shows in perspective a part of a slat of a venetian blind, and the use of individual U-shaped securing brackets,

FIG. 2 is a section, on a larger scale and parallel to the supporting cord, through the slat shown in FIG. 1, showing details of the manner in which the securing bracket is secured underneath a flange of the slat,

FIGS. 3a, 3b and 3c are respectively a plan, a side view, and a front view of the securing bracket used in FIG. 1 and FIG. 2,

FIG. 4 is similar to FIG. 1, but shows a different type of securing device,

FIG. 5 is a side view of the securing device of FIG. 4, the blind being in an obturating position,

FIGS. 6 and 7 are respectively a plan view and a side view of the securing device of FIGS. 4 and 5,

FIG. 8 is a part front view of a blind similar to that of FIG. 1, but having supporting cords which are provided with pre-set bending points,

FIG. 9 is a view similar to FIG. 8, but with the slats held together,

FIG. 10 is an enlarged section of the blind of FIG. 8, with one single connecting point between the slat and the supporting cord,

FIG. 11 is a sectional view of a further form of venetian blind, in which the supporting cords have openings woven in them, and

FIG. 12 is a plan view of the connection of FIG. 11.

FIG. 1 shows a single slat 3 attached to two supporting cords, through each of which passes a strand which at regular intervals (the pitch corresponding to the distance between the respective slats in the blind) is enlarged to form flexible loop-shaped attachments 2 extending out of the cord 1. The slats 3 consist, for example, of plastic or aluminium strips, and are provided on each of their longitudinal edges with a turned under flange 4 which is open on the inside of the slat 3, a continuous slot 5 being formed between the flange and the slat proper.

In addition to a central opening 7 for a pull cord not shown in the drawing, the slat 3 in FIGS. 1 and 2 has, on each flanged edge 4, a slot-shaped perforation 6 into which is inserted a securing device 10 which will be described in detail farther on and by which the slat 3 is connected with the adjacent cord 1. The two perforations 6 are aligned with the opening 7 in the lengthwise direction of the slat.

The securing device consists of a securing bracket 10 which is shown on larger scale in FIGS. 3a, 3b and 3c and which, as viewed from above, as in FIG. 3a, presents a U-shaped outline. The securing bracket 10 is preferably made of a resilient plastics material and has two parallel legs, each with a barb 11 on one side. Each leg has a head 12, of greater cross section than the remainder of the leg and the barbs 11 have surfaces which, when mounted on the slat 3, rest against the flanges 4 and are adapted to their contours. The base of the U-shaped device 10 is constituted by an integral pin 13 bridging the heads 12.

In the assembly of the slat-type blind as shown in FIG. 2 each securing device is inserted in a loop-shaped attachment 2 in such a way that these two elements engage each other like the links of a chain. The two barbs 11 which constitute locking parts are then inserted from the outside through the perforation 6 and through the slot 5 of the flange 4, until the two barbs 11 engage the rear edge of the flange 4 at slot 5. The securing bracket 10 is thus locked to the slat 3 so that it cannot become detached, and the slat 3 is affixed to the cord 1. The distance between the rear edge of the barb 11 and the front edge of the head part 12 is preferably somewhat smaller than the width of the flange 4 on the slat 3, so that this latter edge is clamped with a spring action and the securing bracket 10 is held by the slat 3 with a certain prestressing.

In FIG. 3c the securing bracket 10 is seen from the front. By virtue of the reduced width of the pin 13 grooves are formed above and below pin 13, those grooves being preferably formed in the injection-moulded securing bracket 10 at the time when it is produced. The side walls of these guide grooves provide a lateral interference fit with the loop-shaped attachment 2 of the cord 1, which surrounds the pin 13 of the securing bracket 10 relatively tightly, when the blind is assembled, so that the cord 1 can at all times reliably retain its preselected position in relation to the relevant slat 3.

The arrangement of FIG. 4 differs from that shown in FIG. 1 in that in this case each pair of cords 1 requires only a single securing device in the form of a securing strip 20, which is provided at each of its two ends with a hoop 21 to accommodate a loop-shaped attachment 2. In FIGS. 6 and 7 this securing strip 20 is shown separately and on a larger scale. The securing strip 20 is preferably made from plastics or aluminium and is concave to match the cross sectional shape of the slat 3. The hoops 21 form part of a tongue 22 which protrudes in the manner of a bracket in the direction of the concave side of the securing strip 20 and is separated by two slots 23 from two lateral edge strips which have the normal profile of the securing strip 20. The hoops 21 are thus open to the convex side of the strip.

The securing strip 20 is also provided with a central lateral extension 24 having a rectangular opening 25, through which the pull cord, not shown in the drawing, will eventually pass when the blind is assembled. As may be seen particularly in FIG. 7, two bars 26 are disposed along the longitudinal edges of the opening 25 and extend upwards in the direction of the convex side of the strip 20. The bars 26 act as locking parts for the strip 20, when the system is mounted, as will be described hereinafter in greater detail.

In the mounting of the securing strip 20 to a slat as shown in FIG. 4, those loop-shaped attachments 2 of the pair of cords 1 which correspond to the slat are first inserted in the slots 23 on both sides of the tongue 22, until they engage the concave hoops. The securing strip 20 is now inserted, from the end of the slat 3, so that the strip ends enter the slots 5 and the strip 20 is moved along the slat until the bars 26 enter the opening 7 of the slat 3. The securing strip 20 is now firmly locked in position in relation to the slat 3, and the hoops are closed by the adjacent flanges 4; the cords 1 are thus firmly connected by their loops 2 with the slat 3 so that they cannot become detached.

In FIG. 5 of the drawings the slat 3 is shown in a position produced by adjusting the cords 1, such as occurs when the blind is in the "screened" or obturating position.

In the modification shown in FIGS. 11 and 12, the slat-type blind is provided with supporting cords 31 having loops 32 braided into them in place of loop-shaped attachments. These loops 32 may either consist of openings formed in the fabric when the cords 31 are being braided or be formed by special plastic loop inserts, which are braided into the cord, at the required distances, when it is produced. With this alternative form of the cord 31, securing brackets 34 of plastic are required, which have a front part which engages the flanges 4 of the slat 3 and which are constructed, and equipped with barbs 11, in approximately the same manner as the front part of the securing bracket 10 already described in relation to FIGS. 1 to 3. The head part of this alternative securing bracket 34, however, takes the form of a fork 37 of which the branches form, between them, a slot which accommodates the reversing cord 31 and which is offset by an angle of 90.degree. in relation to the slot between the barbs 11. Each of the branches of the fork 37 is provided with an aperture, a pin 36, with a head, being inserted through the two mutually aligned apertures and affixed therein. This pin 36 passes through the aperture of the relevant loop 32 in the cord 31. This example likewise ensures that the cord 31 is tightly guided in relation to the relevant slat 3.

FIGS. 8 to 10 show a further example of a slat-type blind. It differs from that of FIGS. 1 to 3 by the fact that in this case the supporting cord 41 has woven-in pre-set bending points 42. This cord 41 has a woven-in auxiliary thread 43 which passes zigzag fashion through the main strand of the cord 41 and is looped out at certain points in order to form a loop-shaped attachment 44. In this example the pre-set bending points 42 are produced by prolonging the otherwise even zigzag lay of the auxiliary thread 43 in this position. In each such position, due to the prolonged lay of the auxiliary thread, the cord 41 bends outwards towards the side situated away from the auxiliary thread 43.

As may be seen from FIGS. 8 to 10, pre-set bending points of this kind are provided on each side of a looped-shaped attachment 44 and also in each case centrally between two adjacent slats 3. As may be seen most clearly from FIG. 9, this system offers the great advantage of ensuring that when the slats of the blind are pulled together cords 41 always automatically fold outwards in the zone of each slat 3 and cannot become jammed between the slats 3. The cords 41 are helped to fold outwards by the guide grooves in the securing bracket 10. The pre-set bending point 42 provided in the middle between two slats is offset by an angle of 180.degree. in relation to the pre-set bending points 42 in the vicinity of the slat, so that they can bend outwards in the opposite direction.

Finally, it should be pointed out that the loop-shaped attachments 2 in FIG. 1 and 44 in FIG. 10 surround the pin 13 of the securing bracket 10 far more tightly than is implied by the clearances shown in the drawings for reasons of clarity.

Claims

We claim:

1. A venetian blind comprising a plurality of slats, each having on each outer edge a turned under reentrant flange having a free edge; pairs of supporting cords for supporting and adjusting the inclination of the slats, the cords of each pair being disposed on opposite sides of the slats; and separate securing devices for attaching the slats to the supporting cords, there being one securing area at said outer edge for each securing device, the securing devices being receivable between the slats and the flanges and having locking parts adapted to engage both the outer edge securing areas and the free edge of a respective slat to hold the securing devices in position on the slats.

2. A venetian blind according to claim 1 in which each securing device is in the form of a substantially U-shaped bracket of which the base is adapted to be attached to the associated supporting cord, and each of the legs is formed with a locking part.

3. A venetian blind according to claim 2 in which each locking part is in the form of a barb adapted to lock behind the free edge of the flange.

4. A venetian blind according to claim 3 in which each leg has a head part of enlarged cross section, the base connecting the head parts of the two legs and being of smaller cross section.

5. A venetian blind according to claim 2 in which each of the supporting cords is formed with a projecting loop for each slat, the loop being receivable around the base of a securing device prior to location of that securing device in a slat.

6. A venetian blind according to claim 2 in which each supporting cord is formed with an opening therein for each slat, and each securing device includes a pin receivable in one such opening.

7. A venetian blind according to claim 6 in which the bracket has a forked head adapted to enclose the supporting cord on three sides and to receive securely the pin.

8. A venetian blind according to claim 7 in which the forked head is inclined at about 90.degree. to the plane of the U-shaped bracket.

9. A venetian blind according to claim 6 in which rings are inserted to the openings of the cords.

10. A venetian blind according to claim 1 in which each supporting cord at intervals along its length is formed with preset bending points.