DEVICE TO CONTROL FOLDING OF WINDOW SHADES MADE OF PLEATED PET SUN PROTECTION FILMS

Abstract: The device serves to enable controlled folding and attachment of pleated films. The device, which is preferably mounted at a window, comprises a stop section (2) and a folding film (8) connected thereto. The lateral guide sections (12, 13, or 16) exhibit a lower running surface (11), a lateral guide surface (24) that extends at a right angle to it, an upper running surface (25) that extends at a right angle to said guide surface, and at least one flank (9, Fig. 8) that is formed at a right angle to the upper running surface (25); in the alternative, the device comprises an additional flank (17, Fig. 10) that is formed at a right angle to the lower running surface (11) and is arranged opposite flank (9) in staggered fashion. The single flank or both flanks increasingly engage in cut-outs (10) or (10 and 18) when the film (8) is folded and increasingly disengage from them when the film is unfolded. Said cut-outs are arranged at least in both lateral portions, at a certain distance from the lateral end of the film (8), at least in every second fold on the upper side or on the under side or in every fold on the upper side and on the under side, in the latter case opposite to one another in staggered fashion. PET film (8) is preferred as material for pleated window shades because of its high sun protection efficiency. The device permits controlled and orderly folding, as well as smooth movement of the folds when the window shade is unfolded and extended, as well as lateral support and protection in any conceivable position.

Description: DEVICE TO CONTROL FOLDING OF WINDOW SHADES MADE OF PLEATED PET SUN PROTECTION FILMS The present invention relates to a device for controlled folding, for opening and closing, and for lateral support of pleated materials of any kind, especially pleated window shades or blinds made of transparent PET laminates for high-efficiency sun protection coated with a thin layer of metal. According to the state of the art, the preferred application of transparent sun protection films consists of primarily thin PET (polyethylene terephthalate) laminates having a metallic coat. In general, dark films, i.e. films with low light permeability, are much more effective against strong sunlight than lighter ones. However, in the winter, or at dusk, dark films are often undesirable. For this reason, various manufacturers offer systems that can be opened and closed depending on the season or time of day and according to the position of the sun or the intensity of its rays. At present, various such devices made of light-reflecting, transparent film, such as, for example, vertical lamellar window shades, roll-up blind systems, and various pleated systems are available. The pleated window shades or blinds of this material offer considerable advantages relative to the other systems, but are less successful because the requirement that they function reliably or fold in an orderly manner is not fulfilled satisfactorily or because they are too expensive or come with excessive technical requirements. It is the task of the present invention to achieve reliability and smooth movements during the pleating process, thus during opening and closing, and at the same time provide lateral support to pleated window shades consisting preferably of such transparent film with as few technical components as possible in a simple manner and/or to considerably simplify and improve said window shades relative to the state of the art. SOLUTIONS KNOWN TO DATE In the case of vertical lamellar window shades made of PET film laminates the hanging film blades have the tendency to bulge (i.e. create U-shaped bulges) or to twist around their longitudinal axis, thus creating a "cork-screw" effect. These deformations result in highly bothersome gaps between the hanging film blades, thus enabling light to pass through. Transparent shades made of highly energy- and light-reducing material offer optimum energy and light protection, as well as optimum transparency only when they can be closed completely, i.e. when there are no gaps through which light can pass. Roll-up blind systems or flat hung films also result in undesirable deformations, bulges, or waves. One of the greatest shortcomings of such window shades are the unattractive waves that are visually enhanced in a significant way by the film's shiny and mirroring surface. Though various manufacturers have developed lateral or horizontal fastening devices in order to tighten up such undesirable waves, the results offer only slight improvements. In addition, vertical lamellar window shades and roll-up systems share another disadvantage: The film that is delivered by the manufacturers with a smooth, mirroring surface should be embossed for such applications. The film's propensity for high light reflection (up to 80 and more) would otherwise reflect the incoming sunlight in a concentrated manner onto one point in the environment, thus blinding or disturbing neighbors, traffic, or passers-by. For this purpose, in most cases a pattern having a small grid is embossed onto the material using calender rollers or special presses. However, the embossing significantly reduces the film's transparency. The observer looking through the film from the inside perceives a grid. Furthermore, such films achieve optimal transparency only when the observer looks through them from a point that is perpendicular to the surface; the transparency decreases the flatter the angle of observation. Vertical lamellar window shades cannot be used in horizontal or slanted applications; roll-up systems, for example, can be used in said applications only with the help of transversely tightened cords or wire rope. Roll-up systems that can be moved laterally also require a tightening or counter-acting device in order to prevent the film from sagging. The given folding structure of pleated shades or blinds (Fig. 3 and 4) prevents and suppresses undesired forms of folds or waves, thus preventing aforesaid shortcomings and guaranteeing a uniform and attractive appearance. In addition, this shape prevents the sunlight from being reflected onto a single point; sufficient dispersion of the reflection is guaranteed in each position, thus eliminating the need to emboss the material for this purpose. Since the material does not have to be embossed, it is also much more transparent. Moreover, in most cases such a folding structure does not require additional tightening, counteracting, or supporting devices because up to a certain degree of extension it possesses its own stability, much like corrugated sheets, thus preventing the film from sagging, falling out, or bending. However, when it is folded the resistant PET film material behaves in much more problematic ways than traditional materials normally used for pleated window shades. For this reason, the known solutions used, for example, for pleated window shades made of fabric with draw strings that run parallel to the direction in which the blind is drawn and are threaded through eyelets in each fold of the blind in order to control the folding process cannot be taken into consideration. The film does not move smoothly on draw strings. It jumps, moves in spurts, and some of it is laterally displaced. The smoothness of slide deteriorates the more the folds are extended (5', Fig. 6) , since the friction between the draw strings and eyelets increases correspondingly. Furthermore, since the holes in the film can tear over time, each hole would have to be individually protected, preferably by special longitudinal eyelets. All this results not only in an end product that is more expensive but also in the fact that the device can no longer be folded up tightly because the eyelets pile up on top of each other. Instead of using draw strings as is the case in pleated window shades made of fabric, other known solutions use so-called tightening strings, tightening cords, or rods. However, such controlling devices basically exhibit the same disadvantages. Another solution is described, for example, in EP no. E 06B 9/62, -9/327, or in U.S. patent no. A 4,625,786. Both relate to so-called honeycomb blind constructions or two-ply assembly insulating window shades which are also equipped with draw strings threaded through holes in each double fold. In addition and in a manner similar to the invention, these systems exhibit lateral cutouts in both lateral portions of each fold that are parallel to the direction in which the blind is drawn, as well as a guiding device that engages in it on both sides. Just as in the case of window shades or blinds equipped with draw strings and eyelets, the guides which thus engage laterally in cut-outs lead to increased friction the more the folds are extended. They also do not permit orderly folding of simple pleated blinds, nor do they provide lateral support, without additional draw strings or rods. The lateral arrangement of the guides and/or cut-outs in the aforementioned patents by definition do not intend or claim to control the folding process or to prevent simple pleated window shades or blinds from jumping out or falling down. Instead, they are intended to provide the two-ply assembly with a side edge and an air-tight seal, and to define a path for the lateral guide. DETAILED DESCRIPTION OF THE PRESENT INVENTION It is the task of the present invention in contrast thereto to create a device which makes it possible to control both the folding process and smooth movement during opening and closing of a simple pleated window shade preferably made of PET film, to enable its secure lateral support in horizontal or slanted applications, such as e.g. skylights, as well as to provide a shielding closure in a stationary, opened, half-opened, or closed position. This is to be preferably achieved without any or with as few additional parts or auxiliary devices as possible that are connected to one another or to the guide or film, or that follow the pleating movements of the film, or are threaded through the pleats, thus generating or controlling the desired pleats. It must be possible to use this device for other folding, separation, protection, closure, or cover devices. It must be possible to use the device in a horizontal, vertical, or diagonal position. However, it must also be capable of performing directional changes and winding around corners. This is achieved by the characteristics of patent claim 1. In the following, both the embodiments and their applications are explained on the basis of the enclosed drawing. Fig. 1 shows a folded film Fig. 2 a film that was partially extended after having been compressed in folds Fig. 3 an extended film Fig. 4 a film that has partially retracted after having been extended Fig. 5 a film that folds in an uncontrolled manner after having been extended Fig. 6 a similar representation as in Fig. 4 for the purposes of defining individual terms Fig. 7 a perspective representation of a first embodiment of the invention Fig. 8 a cross-section of the device according to Fig. 7 Fig. 9 a cross-section of a second embodiment of the invention Fig. 10 a cross-section of a third embodiment of the invention Fig. 11 a cross-section of a fourth embodiment of the invention. A pleated window shade or similar folding device is manufactured first by folding the film material transversely to the direction in which the blind is folded (Fig. 1) and subsequently cutting it to the desired length and width. At a certain distance from its lateral end, the folded material is equipped at both lateral ends with at least one cut-out (Fig. 7 or 8) that is arranged parallel to the direction in which the blind is drawn. To facilitate understanding, the cut-outs that are arranged in both lateral portions of the material are referred to as cut-outs on the upper side or underside. Fig. 7 shows cut-outs on the upper side (10) , Fig. 10 cut-outs on the upper side (18), and Fig. 8, 9, and 10 cut-outs on the underside (10) . Fig. 7 presents the principle on the basis of a first embodiment in a perspective drawing. The horizontal position was deliberately selected in order to allow us to define the position of the cut-outs (10 and 18) , as well as the position of the guide flanks (9 and 17) engaging therein, in the following as arranged on the upper and underside. Fig. 7 shows how the system operates, how the parts are assembled, and how the film is moved: The characteristics of this first embodiment comprise a film that is folded halfway (8) . In the lateral portions of every second fold it exhibits cut-outs (10) that are arranged on only one side of the fold on the upper side. This embodiment also comprises one lateral guide section (12) each on both sides, comprising a lower running surface (11) , a lateral guide surface (24) which is bent around this lower running surface at a right angle, an upper running surface (25) which is arranged at a right angle to said lateral guide surface, as well as a flank (9) that is arranged at a right angle to the upper guide surface (25) ; the flank is intended to engage in the guide slits (10) which are arranged symmetrically on the upper side, thus in every second fold in the lateral portion of the film (8) . In the embodiment providing for engagement on both the upper side and the underside according to Fig. 10, provision is made for cut-outs (10 and 18) on both sides, as well as for guide flanks (9 and 17) that are arranged opposite one another in staggered fashion. One end of the cut and pleated film (8) can be firmly connected to a stationary section (2) . The other end of the film can be connected to a moveable or sliding rod so that it can be moved along the lateral guide sections (12) to open and close the device, thus folding or unfolding the film. PET film materials in particular posses a special "memory" to previous deformations which manifests itself more or less visibly at the time external forces are relaxed. The extent to which it reshapes itself after having been relaxed depends on the intensity and continuity of the last thermal or mechanical influences relative to previous influences and forming processes. If the film was pleated tightly the last time (Fig. 1) and is subsequently relaxed, its resulting visual appearance roughly conforms to that represented in Fig. 2. From this position the film could be pleated once again simply by pushing it together without the help of auxiliary devices or guide elements. If it was extended the last time (Fig. 3) , the film will assume a shape roughly conforming to that shown in Fig. 4 which would result in chaotic pleats when it is refolded (Fig. 5) unless auxiliary devices or guide elements are used. Once it has been in the extended position, the film will retract itself at least up to a certain degree in the direction of the original pleats during the first moments of the folding process. According to this invention, the cut-outs (10, Fig. 8) or (10 and 18, Fig. 10) already sufficiently intervene in the guide flanks (9) and (9 and 17) in order to prevent undesired pleats or directional movements. At all times, continued folding increasingly impels the flanks and cut-outs to engage, thus counteracting the increasing counter-pressure to the film's undesired movements or chaotic folding. When the folding film is unfolded, the friction resistance that occurs between said cut-outs and flanks is reduced the more the film is pulled apart, thus avoiding the hesitant movements that occur when draw strings or rods are used. As required for pleated window shades consisting of film, both during folding and unfolding this invention acts in ways diametrically opposed to the action of draw strings, tightening cords, and guide rods, or the guides that engage in cut-outs from the lateral ends: The tightness and inevitability of the guiding force increases with its growing importance during increased folding and decreases, i.e. becomes looser and more relaxed, the greater its bothersome effect during increased extension of the film. Depending on the end use, the lateral guide sections and/or the engaging guide flanks can be replaced by guides made of bent steel wire or guide rods that are attached at both ends and mounted to a window frame for example. Furthermore, on the basis of this principle the straight sections can also be replaced by cylindrical or round sections that run around curves or corners, as well as by guides that open like a fan. A fourth embodiment is shown in Fig. 11. In this case not only the film is pulled in when the window shade is opened: A winding (22) is used instead of the guide flanks (9) , and a winding spring steel band (21) similar to a measuring tape or a band made of another material is used instead of the running surface (1) 1. Though such a system can be pulled in entirely, it nevertheless functions according to the same principle. Fig. 9 shows a second embodiment of the section (13) . Said section offers space on the sides for the guide rollers or slide shoes of the sliding rod or, if necessary, for draw strings or counteracting cords. The running surface (11, Fig. 9) is merely indicated in order to illustrate yet another embodiment: The section can also be formed in a way making it possible to mount it directly in the window frame or between the two window panes of a double window. In these cases, the window pane itself would take the place of the running surfaces (11) , thus eliminating the latter. A rod or a bracket made of rod-shaped material could also be used in place of the lateral guide sections. Such a rod or bracket would engage in the respective upper or lateral cut-outs on both sides of a folded film that functions as a pleated window shade. The guide elements need not be arranged at the same distance from the running surface; for example, they can also run diagonally to said surface, thus engaging more strongly in the cut-outs of the film in one portion than in another. In embodiments where the engagement occurs on both sides, provision may be made for flanks of unequal lengths which would achieve an even more compelling guiding force during the folding process. It is also possible to arrange two or more devices having window shades next to one another. In this case, the guide elements that are not arranged in the outermost lateral portions can be shaped symmetrically, for example by arranging two guide sections (12) according to the invention next to one another or by connecting them to one another in such a manner that the two guide flanks (9) are arranged symmetrically to the middle plane of the double guide section. It is also conceivable to arrange an additional guide element in the middle plane of a very broad film; in this case, the films would also have to be equipped with cut-outs serving as guide slits in the middle plane. Not all forms of cut-outs or sections or arrangements and applications are mentioned here. The examples given are intended to show that the special characteristics of PET films or films made of similar materials used in pleated or other folding devices are controlled by the present invention in multiple and ideal ways. Accordingly, it is not the purpose of this document to restrict the embodiments; instead, its purpose is to prevent others from freely copying devices based on this principle. All normal mechanical parts that are currently in use for window shades and blinds, be it for locking them in different positions, for operating the device with the help of draw strings or wire, whether moved manually or by electrical devices, and all possible initial tension mechanisms or sliding elements that form part of the sections are both known and similar to one another and need not be mentioned separately in this document. As is the case for all systems of this type that function according to the pleating principle or other principles, it is understood that provision must be made for such devices in the present invention with the help of suitable constructions. Both the space required for lateral guiding of the film material and for protection from incoming light, as well as all remaining mechanics according to the present invention are smaller than those required for Venetian blinds: At the top the distance of the device from the window frame is equal to that at the sides, since pleated blinds do not require winding drums. In addition, the construction height can be varied since the depth of the folds (7, Fig. 6) determines the construction height of the lateral sections (12, 13, or 16). In the open position of the window shade, the folded material requires very little space since the film is very thin, does not exhibit additional folds or double folds, and does not require other technical parts that take up a lot of space. The system's simplicity enables users to mount manually operated, pleated window shades themselves. The user can also easily remove the system temporarily or definitively, and clean it. After the frame is loosened, the film is lightly dusted in its extended position with an anti-static duster or cloth and wiped with a chamois. In the alternative, the material can be easily removed from the frame (2, Fig. 5 and 7) and placed on a flat and clean surface for cleaning purposes. Damaged or worn-out films can be easily replaced by the users themselves or by a specialized company in the same manner. This simple system requires very little technical knowledge for such tasks. Apart from applications in windows, this solution is suited not only for tight spaces, extreme positions, or cases where vibrations result from traffic or planes, but also in overhead situations, such as, for example, skylights in domes or roofs, as well as in vehicles, mobile homes, and ships. A similar device can be made to cover moveable machine parts and equipment etc. In contrast to other pleated systems, if the pleated film is pressed or pulled out of its lateral guide by wind, human, or other forces, it does not tear or suffer damage and in most cases can be easily reinserted in the guides.

Claims: PATENT CLAIMS 1. Device for controlled folding and smooth movement during opening and closing of pleated window shades or blinds or similar moveable folding devices, where guide elements (9, 22), which are arranged at a certain distance from the lateral ends on the upper side (9, Fig. 7) or on the underside (9, Fig. 8), engage in cut-outs (10 or 23) arranged in identical fashion in a folded film (8) . 2. Device according to claim 1, where the guide elements and the cut-outs (10, 18, 23) are arranged at least in the lateral portions of the film (8) . 3. Device according to any one of the preceding claims, where the guide elements (9, 11, 17, 24, and 25) are formed as' interconnected components of guide sections (12, 13, or 16) and thus intervene in the folding process in a controlled manner according to claim 1 or 5 with the help of flanks (9, 17) that engage in cut-outs (10, 18) . 4. Device according to any one of the preceding claims, where the guide elements (9, 11, 12; 13; 16, 17) are equipped with a running surface (11) that is perpendicular to the * lateral guide surface (24) . 5. Device according to any one of the preceding claims, where the guide elements (16) comprise flanks (9, 17) serving to engage in cut-outs arranged in both lateral portions on the upper side and on the underside opposite one another in staggered fashion. 6. Device according to any one of claims 1 through 5, where the guide elements consist of wire, bracket, or rod-shaped material (23) serving to engage in the cut-outs (23) in the film (8) . 7. Device according to claim 8, where the guide elements (23) and the running surfaces (21) are winding. 8. Device according to any one of the preceding claims, where the film is equipped with a stop element (3) . 9. Film for a device according to any one of the preceding claims, where the device is equipped with folds arranged transversely to the drawing direction; in its lateral portions the device exhibits cut-outs (10, 18, 23) serving as guide elements. 10. Film according to claim 9, where the cut-outs are arranged symmetrically to every second fold line or every second fold line on both the upper side and the underside.

Inventors: WIRTH HERMANN URS, WIRTH, HERMANN, URS
Applicants: TECOM SERVICES AG, WIRTH HERMANN URS
Application year: 1993
Main classification: E06B9
IPC codes: E06B9