Device for fixing a flexible element to a roller

Abstract: The invention discloses a device for fixing a flexible element (2) to the tubular body (3) of a roller (20) for rolling shutters, guards or blinds, wherein the tubular body (3) has a slot (4) made in its lateral surface (5) and accessible from the outside through a first and a second opening (7, 8), the first oriented at right angles to the axial direction (9), the second at right angles to the tangential direction (10), of the tubular body (3); the radial measurement (D) of the first opening (7) relative to the tubular body (3) is larger than the corresponding measurement (d) of the second opening (8); the flexible element (2) has at one end of it (12) an enlarged fixing head (11) especially shaped to allow it to be inserted into the slot (4) through the first opening (7) and through the second opening (8), remaining trapped inside the slot when the flexible element (2) moves through the second opening (8).

Description: The present invention relates to a device for fixing a flexible element to a roller. The invention applies in particular, but without thereby restricting the scope of the disclosure, to the field of industrial protections, to the manufacture of rolling screens or guards (for example, those used to isolate machine tools) or to protect and guard certain machine parts such as slideways. Protections of this kind have flexible elements which roll up onto rollers and which can be unrolled to prevent machine parts not only from knocking against extraneous objects or coming into contact with shavings or swarf but also from being dirtied by contact with acids or pollutants in general. Similar protection devices may also be used as movable covers, strong enough to be walked on, if necessary, placed over the installation pits of large machines or as rolling covers for tanks. The abovementioned rollers have a tubular body which revolves about its axis so as to roll or unroll the flexible element connected with it by overcoming the force exerted by one or more helical springs located inside the roller itself. Several methods have been used up to the present time to attach the flexible element to the tubular body. According to one of these methods, one end of the flexible element is glued to the tubular body by a layer of suitable adhesive. Although this solution has the advantage of allowing plain tubing, freely available on the market, to be used to make the roller and of dispensing with the need for mechanical parts inside and outside the tubular body, it has numerous disadvantages, the most important of which may be ascribed to the following factors: the unavailability of non-toxic adhesives suitable for applications such as those mentioned above; the hazards created by the solvents used; the difficulty of creating a strong adhesive bond between materials of a very different nature such as, for example, plastics and aluminium alloys or aluminium alloys and stainless steels; the poor resistance of ordinary adhesives to chemicals which may come into contact with them during use; the poor resistance of ordinary adhesives to high and low temperatures; the difficulty of procuring adhesives with specific properties for applications such as those mentioned above; the impossibility of gluing "non-stick" materials such as polytetrafluoroethylene; the difficulty of knowing exactly where a guard or protection will be installed so as to be able to choose beforehand the adhesive most suitable for the ambient conditions. Alternatively, the flexible element may be attached to the tubular body using screws, rivets and similar means. This solution, although it eliminates many of the drawbacks of adhesives listed above, has the disadvantage not only of increasing production costs but also of creating the need for parts inside and outside the tubular body, with sharp points or edges protruding from the inside surface of the tube that may damage the spring mechanisms inside. In yet another method of attaching the flexible element to the tubular body, the end of the flexible element is wound round and fixed to a metal rod which fits into grooves made in the outer surface of the tube. The main disadvantage of this solution is that it may be applied only to very thin, flexible panels which, as such, can satisfy the requirements of a very limited number of applications. Moreover, in addition to requiring tubes that are especially shaped for each specific application, this solution has the further disadvantage that the parts inside the tubular body occupy an excessive amount of space. It is also known, from document US-A-2022807, a device for fixing a curtain to a roller characterized by detachability of the curtain from the roller under abnormal stress. The roller comprises tubular body with a longitudinal slot in which is housed an end fixing head of the curtain. The head is firmed into the slot by a couple of spring clips. When the curtain is abnormally stressed the clips are elastically deformed and let the fixing head go out of the slot. A similar device is shown by document US-A-1333906. in this case the fixing head of a curtain is blocked into a longitudinal slot of the tubular body by an element hinged to said body. When the curtain is overstressed the element rotates on the hinge and release the curtain. The aim of the present invention is to eliminate the drawbacks of all the methods listed above with a device for fixing the flexible element to the tubular body of the roller that can satisfy the requirements of a wide range of applications, particularly as regards the possible combinations of shapes, sizes and materials of the flexible element and of the tubular body. The present invention provides a device as disclosed in claim 1 for fixing a flexible element to a roller with a tubular body. The invention will now be described with reference to the accompanying drawings which illustrate a preferred embodiment of it and in which: Figure 1 is an axial view of a tubular body of a roller made in accordance with the present invention illustrated, for clarity, without the flexible element; Figure 2 is an enlarged view of a part of the tubular body illustrated in Fig.1; Figures 3 and 4 are side views of the end of a flexible element used with the tubular body illustrated in Fig. 1; Figure 4 is a schematic perspective view of a roller equipped with the device disclosed by the present invention. With reference to the accompanying drawings, the numeral 1 indicates a device for fixing a flexible element 2 to a tubular body 3 designed especially to be used as a roller 20, for rolling shutters, guards or blinds, which is illustrated as a whole in Fig. 5, and which forms the subject-matter of a separate patent application filed at the same time by the same Applicant as the present. With reference to Figs. 1 and 2, the body 3 consists of a substantially cylindrical tube, with a slot 4 made in its lateral surface 5 5 and accessible from the outside through a first opening 7 and a second opening 8. The first opening 7 is oriented at right angles to the axial direction 9 of the tubular body 3, whilst the second opening 8 is oriented substantially radially with respect to the tubular body (3). The measurement D of the first opening 7 radial to the tubular body 3 is larger than the corresponding measurement, labelled d, of the second opening 8. The flexible element 2 (see Figs. 3 and 4 in particular) has at one end of it 12 an enlarged fixing head 11 especially shaped to allow it to be inserted into the slot 4 through the first opening 7, according to a movement in the axial direction 9, and to be trapped inside the slot according to the tangential direction 10 as the flexible element 2 crosses the second opening 8. Indeed the measurement of the end fixing head (11) radial to the tubular body is smaller than the measurement of the first opening radial to the tubular body. The fixing head 11 may be inserted into time slot 4 by making it pass through the second opening 8. Once it has moved past the opening 8, the head 11 engages with and is trapped by an area 8a inside the slot 4, again as the flexible element 2 crosses the opening 8. The device 1 includes a wall element 13 with a transverse protrusion 14 extending radially at a distance from the lateral surface 5 of the tubular body 3. The wall element 13 is slotted into the lateral surface 5 of the tubular body 3 and its protrusion 14 projects radially to the tubular body 3 towards the lateral surface 5 in such a way as to define the slot 4, together with the lateral surface 5 itself. The slot 4 (Fig. 2) has a locally recessed bottom 4a on the lateral surface 5 of the tubular body 3. The recessed bottom 4a, in combination with the remaining portion of lateral surface 5, defines an inside corner 4b located under the protrusion 14 of the wall element 13 which together form the part that stops the head 11 of the flexible element 2 against the tangential forces which tend to pull the flexible element 2 out of the slot 4, as will be clarified below. The means for joining the wall element 13 to the lateral surface 5 are shown in Fig. 2 and consist of a rib 15, made on the wall element 13, and a groove 16, made in the lateral surface 5 of the tubular body 3. The rib 15 and the groove 16 are especially shaped to allow the former to slide freely into the latter from the side in the axial direction 9 but to stay together firmly in the radial direction to the tubular body 3. As regards the head 11, Fig. 4 shows the preferred embodiment for thin flexible elements 2 made of fabric, for example, from natural fibres or synthetic plastic fibres, such as "kevlar". In this embodiment, the head 11 is made by connecting to the end 12 of the flexible element 2 a piece 17 of flexible element, made for example of the same material as the flexible element 2, folded into a U round the end 12 of the flexible element 2 itself and attached to the latter by means of stitching 19. The thickness S of the piece 17, measured radially to the tubular body 3, is almost equal to the larger measurement D of the first opening 7 of the slot 4. In addition, the stitching 19 creates two free strips 21 designed to stop against the inside surface 8a of the slot 4. Fig. 3 shows another embodiment of the fixing head 11, used preferably for thick flexible elements 2 such as rolling shutters consisting of rigid steel panels flexibly joined to each other. Fig. 3 shows in particular that the piece 17 is made of a metal material, is attached to the flexible element 2 by means of rivets 22 and has rigid splayed fins 18 which, once inserted into the slot 4 from the side, engage the protrusion 14 and the inside corner 4b in such a way as to prevent the flexible element 2 from being pulled out of the slot 4 in the tangential direction 10. In both the embodiments illustrated, the thickness S of the head 11, during use, tends to increase directly proportionally to the intensity of the pulling force exerted on the flexible element 2. The accompanying drawings illustrate two embodiments of the heads 11 for two specific applications. Although it is evident that, in practice, the rollers may be made for a very wide range of applications, depending on the material used, the size of the flexible element and the method adopted to fix the piece 17, the fixing device 1 disclosed by the present invention may be used for all applications since it makes the tubular body 3 completely independent of the materials and of the physical and chemical properties of the flexible element 2, which must instead be taken into account only for the manufacture of the head 11. In other terms, the advantages of the invention are its modularity, its suitability for all applications, and the low cost of making the joints. The embodiments described can be subject to modifications and variations without thereby departing from the scope of the inventive concept as defined by the appended claims. For example, in the embodiment where the piece 17 is made of metal, it may be attached to the end 12 of the flexible element 2 by means of spot welding.

Claims: A device for fixing a flexible element (2) to a roller (20) with a tubular body (3) the tubular body (3) having a longitudinal slot (4) in its lateral surface (5) accessible from the outside through a first opening (7) and a second opening (8), the said first opening being oriented substantially at right angles to the axial direction (9) of the tubular body (3), and the second opening (8) being oriented radially with respect to the tubular body (3), the measurement (D) of the first opening (7) radial to the tubular body (3) being larger than the corresponding measurement (d) of the second opening (8); the said flexible element (2) having at one end (12) of itself an enlarged fixing head (11) shaped in such a way as to securely engage and become trapped in an area (8a) inside the said slot (4) when the flexible element (2) moves through the second opening (8), the device also comprising a wall element (13) connected to the lateral surface (5) of the tubular body, (3) and set at a distance from the lateral surface (5) in such a way that, together with the latter, it defines the slot (4), characterized in that the said wall element (13) has a protrusion (14) that projects radially towards the lateral surface (5) of the tubular body (3) in such a way as to define the second opening (8) of the slot. The device according to claim 1 characterized in that the measurement of the said end fixing head (11) radial to the tubular body is smaller than the measurement of the first opening radial to the tubular body whereby said end fixing head (11) can be inserted through the first opening (7), according to a movement in the direction (9) parallel to the lengthways axis of the tubular body (3). The device according to claim 1 characterized in that the said wall element (13) is attached to the lateral surface (5) of the tubular body (3) by joining means (15,16) consisting of a rib (15) made on the wall element (13), and a groove (16), made in the lateral surface (5) of the tubular body (3), the said rib (15) and groove (16) being especially shaped to allow the former to slide freely into the latter from the side in the axial direction (9) but to stay together firmly in the direction radial to the tubular body (3). The device according to claim 1 characterized in that the slot (4) has a recessed bottom (4a) on the lateral surface (5) of the tubular body (3) defining an inside corner (4b) against which the said fixing head (11) of the flexible element (2) is stopped and which is located under the protrusion (14). The device according to claim 1 characterized in that the said end fixing head (11) consists of a piece (17) of flexible element folded into a U round the end (12) of the flexible element (2), the thickness (S) of the curved portion of the said piece (17) being almost equal to the measurement (D) of the first opening (7) of the slot (4). The device according to claim 5 characterized in that the said flexible piece (17) is attached to the end (12) of the flexible element (2) by means of stitching (19) which defines two free strips (21) designed to stop against the inside surface (8a) of the slot (4). The device according to claim 5 characterized in that the said piece (17) is made of the same material as the flexible element (2). The device according to claim 5 characterized in that the said piece (17) has rigid splayed fins (18) which interact with the slot (4), engaging at least the protrusion (14) so as to prevent the flexible element (2) from being pulled out of the slot (4) in the tangential direction (10). The device according to claim 5 characterized in that the said piece (17) is made of a metal material. The device according to claim 8 characterized in that the said piece (17) is attached to the flexible element (2) by means of rivets (22). The device according to claim 8 characterized in that the said piece (17) is attached to the flexible element (2) by spot welding.

Inventors: TABELLINI GIORGIO, TABELLINI, GIORGIO
Applicants: PEI PROTEZIONI ELABORAZIONI, P.E.I. PROTEZIONI ELABORAZIONI INDUSTRIALI S.R.L.
Application year: 1996
Main classification: E06B9
IPC codes: E06B9, F16P1