DEVICE FOR ADJUSTABLE PRE-LOADING OF ELASTIC MEANS ASSOCIATED WITH A TAKE-UP ROLLER

Abstract: The device is associated with a plate (1) for closing one head of a box housing a roller (2), with a cylindrical recess (4) made in the plate coaxially to a through hole (5) and into which a bush (6) is placed. The bush is provided with an axial hole (15) with polygonal section and two strikers (8) suited to fit into corresponding notches (7), through the effect of the action of a spring (9) placed inside the recess (4) on a collar (16) integral with the bush, to achieve the locking of the axial rotation of the bush (6); a washer (10), fastened to said plate (1) closes the recess (4) and axially pushing on the bush and rotating the same achieves the release of the strikers (8) from the notches (7), and the adjusting of the pre-loading of elastic means associated to the roller.

Description: This invention relates to the production of accessories for systems having a light-dimming function, to be applied to windows, such as, for instance, the well known vertically-movable window shades. As a matter of fact, many kinds of systems are known, which can be fitted to windows, comprising a window shade which can be moved vertically to vary the surface of the window covered by the blind cloth or by the strips or any other matter which it is consisting of. Such a kind of curtain is generally rolled up on a roller supported horizontally inside a suitable housing, commonly called a box, which is placed over the window, or anyway close to the upper edge of the window frame (see document GB-A-1 487 329). The roller can rotate axially and it is subject to the action of elastic means, placed inside itself, which are fastened to a fixed part with respect to the roller. By unrolling the curtain, the elastic means are loaded. Other locking means provide for the steady positioning of the curtain in the desired position, thus locking the roller. Once the locking means have been released, the elastic means inside the roller cause it to rotate, thus to rewind the curtain. Obviously, for the correct operation of said device, a preliminary loading of the elastic means inside the roller is generally required. Since the fixed part, with respect to the roller, to which the elastic means inside the roller are fastened, must be connected in its turn with a fixed structure, i.e. the rolling blind box in particular, it is clear that the preliminary loading of the elastic means can be carried out only after that the assembly of the accessory in general has been completed. In particular, there are known devices which are positioned close to a head of the roller and supported by the closing plate of the box head, and suited to allow the preliminary loading of the elastic means acting on the roller, as well as the subsequent adjustment of their preliminary loading. Said known devices require a semicircular groove to be made in the surface of the outer plate, with respect to the roller, and also two holes close to the ends of the groove. Two pins, connected with each other by a semicircular metal segment, are inserted into the holes of the plate, to be subsequently inserted into corresponding holes made in a bush, with which the fixed part, holding the elastic means inside the roller, is integral, or in any case mechanically connected. To carry out the preliminary loading, it is necessary to lift the semicircular segment from the relative seating, i.e. the semicircular groove, remove both pins from the holes, operate by means of a suitable tool (screwdriver) and through a hole, made for that purpose in the plate, on the bush, causing it to rotate in either direction up to obtain the desired stretching of the elastic means, and finally insert the pins back again into the relative holes. Obviously, such a device is not very functional, and the operation to carry out the preliminary loading is quite complex. Furthermore, in the case that the preliminary loading is to be adjusted in subsequent phases, the problems arising for the operator are obvious, since he should keep the bush, with just one hand and using a special tool, in the previously determined position, and he should remove both pins from the relative holes at the same time. Then, he should move the bush, and rotate it in either direction, to increase or reduce the tension of the elastic means respectively, while paying attention to avoid releasing the bush itself, which would otherwise release the elastic means which would return to the unloaded position, so involving the need to start the operation again from the beginning. The aim of this invention is to present a device, for carrying out the adjustable preliminary loading of the means associated with a take-up roller, which allows to operate quickly and easily, and avoids the risk of compromising the adjustment made previously every time it is desired to adjust the tension of the elastic means inside the roller. The aim is achieved, according to this invention, through a device for the adjustable preliminary loading of the elastic means associated with a take-up roller for curtains, said device, being obtained in accordance with the Claims hereinafter. The proposed device, besides the extreme simplicity of the preliminary loading or adjustment operations, avoids the possibility of compromising a previous adjustment. The features of this invention not mentioned above are pointed out below, with a particular reference to the enclosed drawings, where: Fig. 1 shows an exploded view of the device being the subject of this invention; Figures 2a and 2b partially show the device in question in a first position, respectively cutaway and viewed from one of its outer sides; Figures 3a and 3b partially show the device in question in a second position, respectively cutaway and viewed from one of its outer sides. With reference to the above-mentioned figures, no. 1 indicates the closing plate of the housing (commonly called rolling blind box), inside which the assembly is placed, made up of the roller 2, of the fixed part to which the elastic means acting on the roller are fastened, and of the curtain wound on the roller. The fixed part, the elastic means acting on the roller, and the curtain wound on the same roller, are not illustrated since they are well known. A small section of the curtain is protruding from the box to be pulled and unwound from the roller. The plate 1 is featured, in almost a central position, with a protrusion 3, e.g. of cylindrical shape, integral with the plate itself. The protrusion originates from the surface of the plate inside the box and directed towards the roller 2, and is also provided with an axial hole defining a cylindrical recess 4 coaxial to a through hole 5 made on the plate 1. Along the lips of the hole 5, two notches 7 are made, in diametrically opposed positions, which are mentioned below. Inside the recess 4 a bush 6 is inserted, one of whose heads is bearing two strikers 8 suited to fit complementarily into the notches 7 while the same head of the bush, corresponding to the strikers, is inserted into the hole 5 until a collar 16, integral with the bush 6 and having a diameter slightly smaller than the inner diameter of the recess 4, strikes against the lips of the hole 5. Finally, the bush 6 is crossed by an axial hole 15, having a rectangular (or polygonal) section, which is mentioned below. Around the body of the bush 6 and inside the recess 4, there are elastic means, which in the example shown are consisting of a helical spring 9 placed so to strike against the collar 16. Finally, to close the hole 5, a washer 10 is provided, which fits into a corresponding seating 11 made on the head of the protrusion 3 and it is fastened to the latter by screws 13. The washer then compresses the spring 9 which provides an elastic reaction against the collar 16, pushing it in the direction G (see fig. 2a). The head of the bush 6 directed towards the roller 2 passes through the hole 12 in the washer 10. The fixed part, to which the elastic means acting on the roller are fastened, is provided with a tang 14 complementarily inserted into the corresponding part of the rectangular hole 15, as it is clearly shown by figures 2a and 3a. With the unit completely assembled, the preliminary loading of the elastic means acting on the roller 2 is carried out by inserting a suitable tool, e.g. a screwdriver, into the rectangular hole 15 of the bush 6, from the outer side of the plate 1, and acting first axially on the same tool, whose increasing section prevents it from sliding inside the hole itself. After that the resulting axial movement of the bush 6 in the direction D has caused the release of the strikers 8 from the corresponding notches 7 (see figures 3a and 3b), the rotation of the tool according to either direction F1 and F2 brings about an analogous rotation of the bush 6, thus of the fixed part, whose tang is inserted in the rectangular hole 15. The elastic means associated with the roller 2 are preloaded in this way up to the desired tension. By removing the tool from the rectangular hole of the bush 6, the spring 9, providing an elastic reaction on the collar 16 of the bush, causes the strikers 8 to fit again into the notches 7, so that the bush and the fixed part are prevented from rotating. Subsequent adjustments may be made by acting again as described above, in a quick and easy way, since by a single tool it is possible to release the fixed part and make it rotate to adjust the preliminary loading of the elastic means. The release of the bush, in fact, occurs only after that the tool suited to cause its rotation has been inserted into the hole 15. In this connection, it is possible to make a variation which makes it possible to carry out the preliminary loading or adjustment of the tension of the elastic means acting on the roller 2, not only by means of a single tool, but also by a single movement. In fact, it is sufficient to change the corresponding edges of the notches 7 and strikers 8 into inclined planes (e.g. by chamfering them), such notches and strikers being placed downstream as to the sense of rotation of the bush which increases the tension of the elastic means acting on the roller 2. With such a constructional variation, it is sufficient to insert the tool and turn the bush 6 in the direction which causes the tension of the elastic means acting on the roller 2 to increase; in this way, the mutual action of the inclined planes of notches and strikers automatically causes the release of the latter ones from the first ones, while the spring 9 restores the coupling of notches and strikers at every turn fraction of the bush corresponding to the number of notches and strikers. To reduce the tension of the elastic means acting on the roller 2, it shall be necessary, in any case, to act axially on the bush 6, as described above. It is to be pointed out, besides the extreme simplicity of the preliminary loading or adjustment operations, that the possibility of compromising a previous adjustment is totally avoided, since it is practically impossible that the bush accidentally slips while the same is being released. According to a further obvious variation of the device,not shown since it may be easily deduced from the above, the protrusion 3 may be made separately from the plate 1, also being therefore provided with the hole with notches into which the bush strikers are fitting. The coupling of the separate body with the plate is achieved by inserting one of its ends, having a reduced diameter for a length equal to the thickness of the plate, into a hole made on the plate, and fastening the same body to the plate by known means, e.g. two screws.

Claims: Device for adjustable preliminary loading of the elastic means associated with a take-up roller for window shades, said device, which is associated with a plate (1) for closing one head of a box housing said roller (2), being characterized in that said plate (1) is provided with a cylindrical recess (4) made coaxially to a through hole (5) made on said plate (1), inside said recess (4) being placed a bush (6) having an axial hole (15) with polygonal section and having two strikers (8) integral with one of its heads suited to fit into corresponding notches (7), through the effect of the action of elastic means (9) also placed inside said recess (4) and acting, according to a sense (G) opposite to said roller (2), on a collar (16) integral with said bush (6), with said notches (7) made along the lip of said through hole (5), to achieve the locking of the axial rotation of said bush (6); a washer (10) being also provided, fastened to said plate (1) for closing said recess (4), with the inner head of said bush (6) passing through the hole of the same washer (10), with the possibility for said bush (6) of being pushed axially according to a direction (D) towards said roller (2), to achieve the release of said strikers (8) from said notches (7), with the possibility of axial rotation for said bush (6) according to opposed senses (F1,F2). Device as in claim 1, characterized in that said recess (4) is made in a protrusion (3), integral with said plate (1). Device as in claim 1, characterized in that said recess (4) is made in a protrusion (3), obtained in a separate body from said plate (1), said body being also provided with a hole along whose lip said notches are made, into which said bush strikers are fitting, said body being also coupled with said plate and fastened to the same. Device as in claim 1, characterized in that said washer (10) is placed inside a corresponding seating (11) made on the inner head of said protrusion (3) being inside said box. Device as in claim 1, characterized in that the adjacent edges of said notches (7) and of said strikers (8) placed downstream as to the direction of rotation of said bush (6) which determines an increase in the preliminary loading of said elastic means acting on said roller (2), are chamfered to make two corresponding inclined planes which cause the release of said strikers (8) from the respective notches (7) following the axial rotation of said bush (6) according to the said latter direction. Device as in claim 1, characterized in that said elastic means (9) acting on said collar (16) of said bush (6) are consisting of a helical spring placed around the body of the bush (6) and inside said recess (4), so resulting to be interposed and striking between the collar (16) and said washer (10).

Inventors: TEDESCHI, GIOVANNI
Applicants: SUNPROJECT S.R.L.
Application year: 1990
Main classification: E06B9
IPC codes: E06B9