TECHNICAL FIELD

The present invention relates to ladder cord assemblies, and more precisely it concerns ladder cords for Venetian blinds and the like.

BACKGROUND

Venetian blinds are used in windows or doors to screen off sunshine or to shut off from view. A common type of window blinds are slat blinds, including a number of horizontal slats connected with strings in a way that they can be rotated to allow light to pass between the slats, rotated up to about 170 degrees to screen off the light, or partly /completely pulled up so that a part/the entire window is clear.

One example of a blind of this type is presented in WO 2011/110544A2. The ladder cord disclosed therein comprises loops through which the lift cords are passed. When a blind of this type is pulled up, the cords will be exposed to friction and thereby wear. This will shorten the lifetime of the blind. Besides, visible loops protruding from the blinds are not very aesthetically appealing. Furthermore, the lift cords are sometimes not efficiently kept together in the pulled-up position.

Another type of blind device is disclosed in EP2562345A2.

From the above it is understood that there is room for improvements.

SUMMARY

An object of the present invention is to provide a new type of ladder cord assembly, in particular for a Venetian blind, which is improved over prior art and which eliminates or at least mitigates the drawbacks discussed above. This object has now been achieved by a ladder cord assembly defined in appended claim 1, with preferred embodiments set forth in the dependent claims, and by a Venetian blind as defined in appended claim 11. In an aspect, there is provided a ladder cord assembly for a Venetian blind, which comprises two side members which are spaced and parallel, and transverse ladder rungs extending between the side members and configured to hold blind slats. Each side member comprises a tilt cord and a lift cord, and each side member tilt cord has a channel in which the lift cord extends. A ladder cord assembly of this kind is advantageous since it provides better control of the lift and tilt cords, less friction when the blind is maneuvered, which in turn yields less wear and longer lifetime of the blind. It is also advantageous since it packs and turns the lamellas or slats more efficiently and reliably. The lamellas are packed closer to each other when the blind is pulled up, which yields an aesthetic result.

In one embodiment, each channel of the ladder cord assembly is arranged alternately on a first side and a second side of the tilt cord. This provides the ladder cord with an integrated channel, which eliminates or reduces the tangling when the blind is pulled up.

In another embodiment, the alternating arrangement of each channel changes on a level flush with each ladder rung. This design is advantageous since it provides the ladder cord which has an aesthetically appealing shape when the blind is pulled up and which eliminates or reduces tangling.

Preferably the lift cords are fitted into the channels such that a top of the lift cord is in line with a top of the channel. This is advantageous since it provides a smooth ladder cord without any protruding elements. In one embodiment the ladder cord assembly is configured to fold the ladder cord in an S-shape when the lift cord is pulled. This structure is advantageous since it is aesthetically appealing, and since it eliminates or reduces tangling.

In another embodiment, each channel is formed as an open, longitudinal recess. An advantage with this channel is that it contributes to the S shape when the blind is pulled up.

In yet another embodiment, each channel is formed as an open thread structure which brings the advantage that it contributes to the S shape when the blind is pulled up.

In still another embodiment, each channel is tube-formed. The tubular channel may either comprise a number of flexible tube sections or an integral, flexible tube element. An advantage with this type of channel is that it contributes to the S-shape when the blind is pulled up.

In a further aspect, there is provided a Venetian blind which comprises at least one ladder cord assembly of the kind described above, and a number of blind slats suspended by the ladder cord assembly. A blind structure of this kind provides efficient screening and smooth operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described in the following, reference being made to the appended diagrammatical drawings which illustrate non-limiting examples of how the inventive concept can be reduced into practice and in which:

Fig. 1 shows a pair of ladder cords with a blind slat arranged on one of the ladder rung pairs according to a first embodiment,

Fig. 2 shows a detail of Fig. 1 on a larger scale, Fig. 3 is a front view of a ladder cord,

Fig. 4 is a similar front view of the ladder cord in Fig. 3,

. 5 shows a Venetian blind provided with a ladder cord partially pulled up,

. 6 shows a close-up of the Venetian blind of Fig. 5 completely pulled up,

Fig. 7 shows the ladder cord with blind slats and a lifting mechanism,

. 8 shows a ladder cord according to a second embodiment,

Fig. 9 shows a detail of Fig. 8 on a larger scale,

Fig. 10 shows a ladder cord according to a third embodiment,

Fig. 11 shows a detail of Fig. 10 on a larger scale,

Fig. 12 shows a ladder cord according to a fourth embodiment,

Fig. 13 shows a detail of Fig. 12 on a larger scale,

Fig. 14 shows a ladder cord according to a fifth embodiment,

Fig. 15 shows a detail of Fig. 14 on a larger scale,

Fig. 16 shows a ladder cord according to a sixth embodiment,

Fig. 17 shows a detail of Fig. 16 on a larger scale,

Fig. 18 shows a ladder cord according to a seventh embodiment, and Fig. 19 shows a detail of Fig. 18 on a larger scale.

DETAILED DESCRIPTION

Certain embodiments will now be described more fully hereinafter with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In the following, various embodiments - in the shape of slightly different types of ladder cord assemblies of a Venetian blind - are described. All these ladder cords have the same basic structure, namely: two spaced, parallel side members and a number of transverse ladder rungs extending between these side members. Each longitudinal side member has a tilt cord and a lift cord. Furthermore, each ladder cord side member has an integrated channel in which the lift cord extends. Hence, the longitudinal channel encloses at least partially the lift cord and it serves as a guide for the lift cord. In Fig. 1 there is shown a pair of ladder cord assemblies 1, each comprising two side members la, lb. Each ladder cord assembly 1 comprises two tilt cords 2a, 2b, two lift cords 3 a, 3b and a number of transverse ladder rungs 4. In each tilt cord 2a, 2b there is arranged an elongate recess or channel 5a, 5b, in which the lift cord 3a, 3b is fitted. A blind slat or lamella 6 (shown in dotted lines) is arranged on one of the ladder rung 4 pairs for illustration purposes.

Each lift cord 3 a, 3b is slidably fitted in its corresponding channel 5 a, 5b in a way that it alternates between being on a first side and on a second side of the tilt cords 2a, 2b. Hence, each lift cord 3 a, 3b changes from the first to the second side, on a level with a first ladder rung 4, and back from the second to the first side on a level with a next ladder rung 4, and so on along the whole axial length of the ladder cord la, lb. Each channel 5 a, 5b is open, that is, each lift cord 3 a, 3b arranged in its corresponding channel 5 a, 5b is always visible from at least one side of the side member la, lb.

Each side member la, lb comprises a respective tilt cord 2a, 2b, and the lift cord 3a, 3b in each tilt cord 2a, 2b does not come up on the same side, as the figure shows. The lift cord 3a comes up against the viewer of the figure, whereas the lift cord 3b comes up away from the viewer of the figure. Each tilt cord 2a, 2b is provided with an aperture 20b on a level with each ladder rung 4, for the lift cord 3 to pass through (see Fig. 2).

One advantage with the new type of tilt cord 2a, 2b compared to prior art tilt cords with loops, is for instance lower friction when pulling the blinds. This results in easier maneuvering and also reduced wear on the cords, which in turn results in longer life-time of the blind. Another advantage is better control of the tilt 2a, 2b and lift cords 3a, 3b, reducing the risk of tangling.

The ingenious arrangement of the lift cord 3b in the side member lb is shown in more detail in Fig. 2. When the lift cord 3b is pulled, it smoothly fits in the longitudinal channel 5b formed in the side member lb. Hence, the channel 5b guides the lift cord 3b in a very efficient manner. The aperture 20b is made relatively small, i.e. the part of the tilt cord 2b that is provided with transverse portions 16, forming the channel 5a, 5b for the lift cord 3a, 3b, has a larger extension compared to the aperture 20b. In a preferred embodiment, the extension of the transverse portion 16 is about half of the axial extension of the aperture 20b between two transverse portions 16. This dimension of the aperture 20b is favourable for the lifting operation of the blind. The transverse width of the aperture 20b is slightly larger than the diameter of the lift cord 3b so that a close fit is achieved.

The ladder cord 3 is further illustrated in Fig. 3, providing a good view of the lift cords 3 a, 3b arranged in their corresponding channels 5 a, 5b. Here can also be seen that the lift cords 3 a, 3b extend in the channels 5 a, 5b at alternating sides of the side member la, lb. Also seen is that each ladder rung 4 comprises two parallel strings.

Fig. 4 also shows the ladder cord assembly 1 from the front, and in this figure it can be seen that the ladder rung 4 connects with the tilt cord 3 a, 3b in the center of the aperture 20b provided for the lift cord 3 a, 3b. The ladder cord 1 may come in several dimensions. For example the length, width, distance between the ladder rungs 4, and/or thicknesses of the strings may be varied and adjusted to preset conditions. In Fig. 5 the ladder cord assembly 1 is shown in use with blind slats 6 which are arranged on the ladder rungs 4 and which may form a screen. The blind is partly pulled up, showing how the channels 5a, 5b make the ladder cord 1 to fold in an S- shape. The ladder cord 1 also contributes to turn and pack the slats 6 more efficiently and securely. Nicer packed slats 6, no protruding loops or other things, and that the lift cords 3 a, 3b are hidden inside the channels 5 a, 5b make the overall looks nicer and more aesthetic appealing.

With reference to Fig. 6 a close-up of the ladder cord assembly 1 is shown with slats 6 inserted, and the blind is completely pulled together. The ladder cord 1 is folded into the S-shape and the slats 6 are nicely packed.

In Fig. 7 the ladder cord 1 is shown illustrated in connection with a lift mechanism of a Venetian blind, with blind slats 6 put on the transverse ladder rungs 4. The lift cord 3 a is shown both entering the lift mechanism (top) and fitted in the channel 5a (bottom).

A slightly modified ladder cord 1 according to a second embodiment is shown in Fig. 8. The principal structure is the same as in the first embodiment, which has been described in detail. The difference here is that the lift cords 3a, 3b run in parallel in the channels 5a, 5b, that is, they come up at the same side in the end of each side member la, lb instead as before, where they come up on different sides. Shown in Fig. 9 is a detail of Fig. 8 on a larger scale. Here can be seen the lift cord 3b passing through the aperture 20b in the channel 5b.

In Fig. 10 a ladder cord assembly 11 according to a third embodiment is shown, where the tilt cords 12a, 12b have fewer transverse portions 16 which build up the channel 15a, 15b, compared to the first and second embodiments. The aperture 120b has similar dimensions as the aperture 20b described in the embodiment shown in Fig. 2 and 9. Thus, the axial extension of the aperture 120b is relatively small in comparison with the distance from one ladder rung 4 to the next.

The lift cords 13 a, 13b come up at different sides in this embodiment. Shown in Fig. 11 is a detail of Fig. 10 on a larger scale. Here is shown the lift cord 13b extending through the aperture 120b in the channel 15b. A ladder cord 21 according to a fourth embodiment is shown in Fig. 12. In this embodiment, the basic structure is the same as in the third embodiment, that is, the tilt cord 22a, 22b comprises fewer transverse portions 16 which build up the channel 25 a, 25b, compared to the first embodiment. The lift cords 23a, 23b come up at the same side in this embodiment. Shown in Fig. 13 is a detail of Fig. 12 on a larger scale. Here it is shown how the lift cord 23b extends through the aperture 220b in the channel 25b. The aperture 220b has similar dimensions as the apertures 20b and 120b described in the embodiments shown in Figs 2 and 9. Thus, the axial extension of the aperture 220b is relatively small in comparison with the distance from one ladder rung 4 to the next. In Fig. 14 a ladder cord 31 according to a fifth embodiment is shown, where the tilt cord 32a, 32b has a channel 35a, 35b made of a thread structure comprising three longitudinal threads, beside a main thread, held together by transverse rings. The lift cord 33a, 33b extends straight through this channel 35a, 35b. Shown in Fig. 15 is a detail of Fig. 14 on a larger scale, illustrating the details of the channel 35b and the lift cord 33b extending therethrough. An aperture 320b is also illustrated, where the distance between the transverse rings 316 is relatively small compared to the distance between one ladder rung 4 and the next.

A ladder cord 41 according to a sixth embodiment is shown in Fig. 16, where the tilt cord 42a, 42b comprises a channel 45 a, 45b made up of by a number of flexible tube sections 416 extending vertically between the ladder rungs 4. The tube sections 416 are arranged on the outside of the main thread of the tilt cord 42a, 42b. There are apertures 420b between the tube sections 416 at a level of each ladder rung 4. The lift cord 43 a, 43b extends straight through this channel 45 a, 45b. Between two tube sections an aperture 420b is formed. The axial extension of the aperture 420b is relatively small compared to the length of a tube section 416. Shown in Fig. 17 is a detail of Fig. 16 on a larger scale, showing the details of the channel 45a, 45b and the lift cord 43 a, 43b extending therethrough.

In Fig. 18 a ladder cord 51 according to a seventh embodiment is shown, where the tilt cord 52a, 52b comprises a channel 55a, 55b made up by of one longitudinal, integral tube which is flexible. The lift cord 53a, 53b extends straight through this tubelike channel 55a, 55b. Shown in Fig. 19 is a detail of Fig. 18 on a larger scale. Here it can be seen the details of the channel 55b and the lift cord 53b extending there through.

Finally it should be mentioned that the inventive concept is by no means limited to the embodiments described herein, and many modifications are feasible without departing from the scope of the invention defined in the appended claims. For instance, the number of ladder cords mounted to a Venetian blind can vary. Furthermore, the inventive concept is not limited to a certain number of slats.

An inventive blind structure may also comprise a bottom slat and a top slat, and vertical ladder cord assemblies extending between these slats. The screen between the bottom and top slats may comprise textile, plastic, paper or a similar flexible material. The operation of such a blind structure may very well be of similar kind as described herein. In a variant, there may be one or more intermediate slats between the bottom and top slat; that is integrated in the blind material.