The invention relates to a suspension device for curtains, comprising a strip capable of being attached to a curtain and a hook member capable of being adjustably attached therealong, with a retaining plane extending from the hook member on both sides of the strip, which retaining planes together bound a slot, and the strip and the hook member comprising a number of cooperating stop projections and stop recesses. Such a suspension device is known from Dutch laid- open application 75.07991. In the known suspension device, the strip is designed as a sliding rail, and the hook member consists of a hook comprising a slide which is slidable over the sliding rail. At a distance from the front side, the strip has a first flange, extending at right angles to the plane of the strip and having a number of stop recesses which form a stop toothing. Along the front side of the strip a second flange extends parallel to the first flange. The recesses are inclined in the longitudinal direction of the strip. The slide of the hook member comprises a resilient stop projection designed as a hook, which projection is capable of springing in a direction at right angles to the two flanges and can partly be received in one of the stop recesses. Further, the slide comprises a groove capable of receiving the edges of the second flange, preventing the slide from being removed from the sliding rail in a forward or lateral direction.

The slide can be slid in the longitudinal direction of the strip so that the resilient projection is received in one of the recesses from the front side. This known suspension device has as an advantage over known metal Z-shaped hooks that they can be washed along with the curtains and can be adjusted in the height direction of the curtain, enabling using different types of curtain rails and runners and performing length corrections of the curtain.

When the hook is loaded by a curtain suspended from the strip, a moment is exerted on the slide in the plane defined

by the hook, in or parallel to which plane also lies the springing direction of the resilient projection. Due to this moment, the slide is tilted between the first and the second flange, causing the flanges to be loaded. In particular upon extra loading of the suspension device, for instance by pulling the curtain open or closed, and in the case of heavy curtains, the flanges and stop provisions should be sufficiently strong to prevent the slide from tilting, because otherwise damage to the device will occur. Moreover, already at a relatively slight tilting of the slide and/or deformation of the slide or the strip, the stop projection will come loose from the stop recess, causing the curtain to come loose from the hook member.

To obtain sufficient strength, the flanges of the known device should be of a thick and wide design and the stop hooks should be proportionally wide, as a result of which the manufacture of the suspension device requires much material and the suspension device is relatively expensive. Moreover, on account of this, the suspension device has of necessity a relatively large width. The drawback thereof is that the curtain, in slid-open position, keeps occupying a large width, which offers an unpleasant appearance and, for instance in the case of a curtain before a window, causes a part of the light surface of the window to be lost. Hence, the object of the invention is to provide a suspension device for curtains of the type described in the opening paragraph, wherein the above-mentioned drawbacks are avoided while the advantages are maintained. To that end, the suspension device according to the invention is characterized in that at least one stop projection is capable of springing in a direction extending substantially at right angles to the retaining planes so that a free end of the stop projection is movable into and out of a stop recess transversely to the strip. Because the stop projection is capable of springing in a direction extending substantially at right angles to the retaining planes and is thus movable into and out of a stop

recess, the stop projection can be of a wider design than in the known suspension device, while the suspension device can be of a narrower design. Upon a possible tilting of the hook member relative to the strip, occurring due to the hook member being loaded, the stop projection does not come out of the stop recess, as a result of which a proper coupling between the hook member and the strip is always maintained while the strip can moreover be of a relatively torsion-weak design. Hence, a suspension device according to the invention requires less material and can be of a narrower design than the known hook of a comparable carrying strength.

In further elaboration of the suspension device according to the invention, the strip is provided with a series of regularly spaced stop recesses, one above the other, with the retaining plane comprising at least one resilient stop projection on both sides of the strip, the resilient projections extending in an inclined manner relative to the longitudinal direction of the slot at least to near the center of the slot, in the direction of the end thereof that is to be referred to as the upper end. The recesses are preferably designed as holes continuing toward both sides of the strip.

Because both retaining planes comprise a resilient projection and the strip is provided with a series of recesses, the strip can be of a particularly thin design without the strength of the suspension device being adversely affected thereby. After all, the strip is retained between the two retaining planes and upon deformation of the strip in the direction of one of the retaining planes at least one of the resilient projections will be further pressed into a recess, as a consequence of which the load capacity of the projections collectively is maintained. The projections, inclining from both sides of the strip in the direction of the center of the slot, have the advantage that when a substantially vertical, downward load is applied to the suspension device, for instance due to the weight of the curtain and when the curtain is pulled open and closed, the projections will be slightly bent, each one in the direction of the opposite retaining

plane. This involves the projections crossing the center of the slot, as a result of which the free ends of the projections in the strip will at least be disposed one above the other. This will cause the bearing area of the projections to increase with the magnitude of the load of the suspension device. By designing the recesses as through holes, maximum effectiveness can be achieved with a minimum of material.

In a preferred embodiment of the suspension device according to the invention, each retaining plane is built up of a series of wall parts extending from a body of the hook member, openings being included between the wall parts such that, in side view, the wall parts and resilient projections on one side of the strip do not overlap the wall parts and resilient projections on the other side of the strip, and preferably approximately connect to each other. Each resilient projection is connected with a first wall part located in the central area of the slot, which first wall part is wider than second wall parts near the beginning and end of the slot, and each second wall part is wider than the stop recesses. The hook member according to this preferred embodiment has the advantage that its manufacture requires a minimum of material without the strength of the suspension device being adversely affected thereby. Moreover, the hook member can be manufactured in a simple manner through injection molding, for which a die divided along a center plane can be used. After all, the wall parts and projections located on one side of the slot can be approached with a die part from the other side of the slot, between two wall parts, and the other way round. Thus, an undercut can simultaneously be formed in the wall parts without an extra core having to be included in the injection molding die for that purpose. Such an undercut offers the possibility of including a flange provided at the front side of the strip and extending in the longitudinal direction thereof. This flange on the one hand stiffens the strip so as to provide it with a greater bending stiffness, and on the other hand ensures that the hook member is retained on the strip in the directions other than the longitudinal

direction of the slot. The second wall parts are wider than the recesses, which prevents these wall parts from being received in the recesses. Thus, these wall parts provide a proper guiding and positioning of the hook member relative to the strip.

When the suspension device is loaded during use, the greater part of the forces exerted on the hook member is taken up by retaining faces constituting the central part of the slot. Hence, it is particularly advantageous if the first wall parts in the central area are of a wider design than the second wall parts near the upper and lower ends of the slot, and if the first wall parts moreover comprise resilient projections. As a result, an optimum force transmission to the hook member and to, for instance, a curtain rail is obtained with the suspension device.

To explain the invention, an exemplary embodiment of a suspension device according to the invention will hereinafter be described, with reference to the accompanying drawings . In these drawings: Fig. 1 is a rear view of a hook member according to the invention;

Fig. 2 is a side elevation of a strip according to the invention;

Fig. 3 is a side elevation of the hook member according to Fig. 1 mounted on the strip according to Fig. 2;

Fig. 4 is a sectional rear view of the suspension device taken on the line IV-IV in Fig. 3; and

Fig. 5 is a sectional bottom view of the suspension device taken on the line V-V in Fig. 3, sewn in the pleat of a curtain.

Fig. 1 is a rear view of a hook member 1, comprising a body 2 and a number of wall parts 3-7 extending from the rear side thereof: three on the left-hand side 8 and two on the right-hand side 9. The wall parts 3-7 together bound a slot 10 extending in the longitudinal direction of the hook member 1. The first wall part 3 located on the left-hand side 8 in the center is provided, on its side facing the slot 10, with a

first resilient projection 12 extending in an inclined manner in the direction of the upper end 11 of the slot 10 and beyond the central longitudinal plane M of the slot 10. The lowermost second wall part 4, located on the right-hand side 9, is provided, on the side facing the slot 10, with a comparable second resilient projection 13.

Viewed in the longitudinal direction of the slot 10, the third wall part 5, located on the left-hand side 8 under the first wall part 3, is narrower and lower than the first wall part 3, and the fifth wall part 7 located above the first wall part 3 is narrower than the first wall part 3 but wider than and equally high as the third wall part 5.

The fourth wall part 6 located on the right-hand side 9 above the second wall part 4 is narrower than the second wall part 4 but wider than and equally high as the fifth wall part 7. The first resilient projection projects outside the first wall part 3 in the longitudinal direction of the slot 10 through a length LI, and the second resilient projection 13 projects outside the second wall part 4 through a length L2. The fourth wall part 6 is provided, at the lower corner pointing toward the first resilient projection 12, with a guide face 35, extending in an inclined manner relative to the central longitudinal plane M of the slot 10 and at right angles to the body 2, and the first wall part 3 is provided, at the lower corner pointing toward the second resilient projection 13, with a second guide face 36, likewise extending in an inclined manner relative to the central longitudinal plane M of the slot 10 and at right angles to the body 2, which second guide face 36 constitutes the extension of the first resilient projection 12.

Included between the third wall part 5 and the first wall part 3 is a first opening 14 whose width equals the sum of the width of the second wall part 4 and the length L2 of the resilient projection 13. Included between the second wall part 4 and the fourth wall part 6 is a second opening 15 whose width equals the sum of the width of the first wall part 3, the length LI of the first resilient projection 12 and the

length L2 of the second resilient projection 13. Included between the first wall part 3 and the fifth wall part 7 is a third opening 16 whose width equals the sum of the width of the fourth wall part 6 and the length LI of the first resilient projection 12. The upper edge 17 of the fourth wall part 6 lies at the same height as the lower edge 18 of the fifth wall part 7, and the upper edge 19 of the third wall part 5 lies at the same height as the lower edge 20 of the second wall part 4. At their sides facing the slot 10, the wall parts 3-7 each comprise an undercut located near the body 2 of the hook member so that by the undercuts together a second slot 21 is formed near the body 2 which second slot is parallel to the slot 10 but slightly wider. At the front side, the body 2 comprises a hook 22 that is open toward the lower end and located in the central longitudinal plane M of the slot 10.

The hook member 1 can be manufactured through injection molding from a minimum of material, the injection molding die comprising only two parts and being divided along a plane parallel to or coinciding with the central longitudinal plane M of the slot 10. The first 3, third 5 and fifth wall part 7 can be approached from the opposite right-hand side 9 of the slot, inter alia through the second opening 15, readily enabling the undercuts in these wall parts, which undercuts form the second slot 21, and the first resilient projection 12 to be formed integrally therewith. The second 4 and fourth wall part 6 and the second resilient projection 13 can similarly be approached from the left-hand side 8 through the first 14 and third opening 16. The hook 22 is located in the dividing plane of the die. Consequently, this embodiment of the hook member according to the invention has the advantage that it can be produced in one pass from a minimum of material with a relatively cheap die, enabling cheap production of the hook member. Fig. 2 is a side elevation of the strip 23, which strip has an H-shaped section, the legs of the H being formed by a first flange 24 and a second flange 25. The central bar of the

H is formed by a strip portion 26 having a series of recesses

27, provided at regular intervals and extending almost throughout the width of the strip portion 26, which recesses are open toward both sides of the strip portion 26. Extending from the second flange 25 in the plane of the strip portion 26 is a fastening flap 28. As is shown in Fig. 5, the strip 23 can be fixed in a curtain 39 by means of this fastening flap

28, for instance by sewing up.

The lower edge 29 of each recess 27 is formed by two faces 30, inclined toward one another and symmetrically arranged relative to the central longitudinal plane S of the strip 23. The distance between the upper edge 31 of a recess 27 and the upper edge 31' of an adjacent recess 27' is always equal to the distance between the upper edge 32 of the first resilient projection 12 and the upper edge 33 of the second resilient projection 13. The distance between the first flange 24 and the second flange 25 approximately corresponds to the height of the first 3 and second wall part 4. As clearly appears from in particular Fig. 5, the first flange 24 has a width that approximately corresponds to, but is certainly not larger than the width of the second slot 21 in the hook member 1, and the width of the second flange 25 approximately corresponds to the width of the hook member 1. In the fastening flap 28, two engaging openings 34 are provided, one above the other, with which the strip can be gripped and manipulated by a feed device, not shown in the drawing.

With particular reference to Figs 3 and 4, it will be indicated how the hook member 1 according to the invention can be used. The hook member 1 is slid on the strip 23 from the top side, with the first flange 24 being fittingly received in the second slot 21, the strip portion 26 being fittingly disposed between the second wall part 4 and the third wall part 5 and the second flange 25 extending above these wall parts. If the strip 23 is further slid into the slot 10, the front edge 37 of the strip 23 is pressed against the second resilient projection 13, causing this projection to be elastically

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