Abstract:
The invention provides a panel ( 2 ) of controllable radiation transmissivity, including a plurality of tubular cells ( 4 ), in at least some of which cells is rotatably mounted at least one radiation-blocking member ( 6 ), at least one portion of at least one surface of which is substantially opaque, and means ( 8 ) for rotating the radiation-blocking member ( 6 ) inside the tubular cells ( 4 ), wherein the radiation-blocking member ( 6 ), when rotated, is adapted, in at least one angular position, to substantially block the passage of radiation through the panel ( 2 ), and in a plurality of other, selectable, angular positions, to provide a plurality of differing radiation transmissivities.

Description:
TECHNICAL FIELD 
     The present invention relates to a panel of controllable radiation transmissivity for the construction of walls, roofs, awnings, skylights, windows, and the like. 
     BACKGROUND ART 
     While panels for the above or similar purposes are known, they are either transparent, translucent or opaque, but their transmissivity is predetermined and cannot be altered or modified. Yet such alterability would be most useful, especially in hot climates where reduced insolation during the hot hours would reduce air-conditioning costs, or in cold climates where increased insolation would reduce heating expenses. 
     U.S. Pat. No. 5,600,920 describes a motorized louver blind structure including slat members operable inside a chamber formed by a double-glazed window unit, to effect pivoting of the slats. 
     DISCLOSURE OF THE INVENTION 
     It is thus one of the objects of the present invention to provide a panel for the construction of roofs, walls, awnings, skylights, windows and the like, the radiation transmissivity of which can be set at will to any state, from almost full transparency or translucency to almost total opacity. 
     According to the invention, the above object is achieved by providing a panel of controllable radiation transmissivity, comprising a plurality of rotatably mounted radiation-blocking members, each of said members having at least one portion which is substantially opaque, and means for rotating said radiation-blocking members, said radiation-blocking members, when rotated, being adapted in at least one angular position to substantially block the passage of radiation through said panel, and in a plurality of other, selectable, angular positions, to provide a plurality of differing radiation transmissivities, characterized by a plurality of substantially transparent tubular cells, at least one of said radiation-blocking members being mounted in at least some of said tubular cells, and means for rotating said radiation-blocking members inside said tubular cells. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood. 
     With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. 
     In the drawings: 
     FIG. 1 is a perspective view of a fully assembled panel according to the invention; 
     FIG. 2 illustrates a first arrangement for mounting the panel on the purlins of a roof structure; 
     FIG. 3 shows a different type of clamping rail; 
     FIG. 4 shows a second arrangement for mounting the panel on the purlins of a roof structure; 
     FIG. 5 shows a first profile of the cells of the panel member according to the invention; 
     FIGS. 6 to  8  represent other possible profiles of the cells; 
     FIG. 9 is a perspective view of a preferred embodiment of the radiation-blocking member according to the invention; 
     FIG. 10 is an end view of the radiation-blocking member of FIG. 9, located inside a cell; 
     FIG. 11 is a perspective view of another embodiment of the radiation-blocking member; 
     FIG. 12 is a perspective view of yet another embodiment of the radiation-blocking member; 
     FIG. 13 is a variant of the radiation-blocking member of FIG. 12; 
     FIG. 14 is an end view of still another embodiment of the radiation-blocking member; 
     FIG. 15 is an exploded view of a panel according to the invention; 
     FIG. 16 is a perspective view, to an enlarged scale, of a portion of the assembled drive mechanism; 
     FIGS. 17 and 18 are perspective views illustrating a different means for rotating the radiation-blocking members; 
     FIGS. 19 a - 19   d  schematically show different limit positions of the radiation-blocking member; 
     FIG. 20 is an elevational view of the panel of a further embodiment, including a variant of the radiation-blocking member of FIG. 9; 
     FIG. 21 is an exploded view of the embodiment of FIG. 20; 
     FIG. 22 is a perspective view of part of the panel, showing the motor, the plurality of gearboxes and the drive shaft; 
     FIG. 23 is a view of the gearbox in cross-section along plane XXIII—XXIII in FIG. 24; 
     FIG. 24 is a top view of the gear box; 
     FIG. 25 is a view of the gearbox in cross-section along plane XXV—XXV in FIG. 24; 
     FIG. 26 is a perspective view of the gearbox as cross-sectioned in FIG. 23; 
     FIG. 27 is a perspective view of the coupling as seen from the side of the drive fingers, and 
     FIG. 28 represents a side view showing the mechanical assembly as clamped onto the panel. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, there is seen in FIG. 1, representing a perspective view of a complete panel according to the invention, a panel body  2  with a substantially planar top surface, and comprised of a plurality of cells  4 . Advantageously, cells  4  are parts of an integral, transparent extrusion of such plastic materials as polycarbonate, PMMA or PVC, although it would be possible to produce a panel by extruding single cells and joining them side-to-side by one of the known methods (cementing, ultrasonic welding, etc.) to form a complete panel body  2 . The upper, sun-facing surface of panel body  2  is advantageously given a per se known treatment to make it UV-resistant. Optional cross-sections of cells  4  will be discussed further below. 
     The term “light,” as used in the description, is meant to include not only the spectral range of visible light, but also ranges of electromagnetic radiation below and/or above that spectral range. 
     Inside cells  4  there are rotatably mounted light-blocking members  6 , the purpose of which is to substantially block the passage of light in one angular position, while providing a plurality of different light transmissivities in a plurality of other, angular positions. Possible configurations of light-blocking members will be described further below. Rotation of members  6  is effected by a mechanism to be explained further below. 
     Further seen is an electric motor  8 , advantageously a 12 V, d.c. gear motor, mounted by means of two brackets  10  on a casing comprised of a lower member  12 , an upper member  12 ′ and a cover plate  14 , which in FIG. 1 is partly cut away to reveal part of the mechanism to be described further below. 
     The rear end of panel body  2  is closed off by a plastic or metal molding  15 . The first and last cells of panel body  2  do not necessarily accommodate light-blocking members  6  because, as will be shown (FIG.  4 ), in some embodiments the first and last cells serve for mounting the panel on the purlins of a roof structure. 
     As, again because of the extrusion process, the width of panel bodies  2  is limited, while no such limitations obtain regarding length, roofs are covered by cutting panel bodies to the required length and attaching them in juxtaposition to the purlins of the roof structure. To this end, the panels have to be joined side-to-side in a way that will provide mechanical strength and will also be waterproof. 
     Two of many different solutions to this problem are clearly shown in FIGS. 2-4. In a first embodiment (FIG.  2 ), panel body  2  is provided with flanges  16  extending along both of its longitudinal edges, the inside surfaces of which flanges are saw-toothed. There is also provided an extruded, hollow, winged aluminum rail  18  between the two wings of which fit the empty cells  4 ′ of the two adjacent panel members  2 , including their respective flanges  16 . After rail  18 , with the adjacent panel members  2  in position as shown, has been fixedly attached to purlins P of the roof structure by means of screws  20 , a plastic, U-shaped clamping rail  22  having matching saw-toothed wings  24  is pushed over flanges  16  of adjacent panel members  2 , providing a strong clamping force. For even greater rigidity, instead of plastic rail  22  it is possible to use an appropriately shaped aluminum rail  26  (FIG.  3 ). 
     Another solution is illustrated in FIG.  4 . Here, an aluminum extrusion  28  is introduced into empty cell  4 ′, filling its entire longitudinal extent and imparting to it mechanical strength. Two more profiles are used: a trough-like, bottom profile  30  which fits the rounded underside of cells  4 , and a two-winged, top profile  32  which rests on the upper surface of panel members  6  and, with the aid of screw  20 , forces the two adjacent panel members  6  (of which only one is shown) against purlin P. 
     Cells  4  can have various cross-sectional shapes, such as the escutcheon shape of FIG. 5, a more elaborate form of which is provided along the rounded portion of its inner surface with prism-shaped serrations  34  which have both an aesthetic and an optical effect. The aesthetic effect is twofold: the longitudinal lines produced are pleasing in themselves, and the serrations also hide the “innards” of the cells, in particular, scratches and wear marks that would be produced on a smooth inside surface by the rotation of light-blocking members  6 . Optically speaking, the prismatic serrations produce a softer, diffused light. A second version of this profile is provided with another layer  36  below the top surface of panel body  2 , for improved thermal insulation. In all cells  4  the internal height advantageously exceeds the internal width, so that flexing of the panel will not cause jamming. 
     FIG. 6 shows a rectangular profile of cells  4 , in which panel body  2  has two planar surfaces. 
     FIG. 7 shows a cell  4  with a circular profile. Panel body  2  of this embodiment also has two planar surfaces. 
     FIG. 8 is another escutcheon-type profile, with a wavy top surface. 
     Light-blocking members  6 , as already mentioned, are rotatably mounted in cells  4  and, their surfaces having a substantially opaque portion, the angular position of this portion inside cell  4  determines the light transmissivity of the cells which, by controlling this position, may thus be controlled between a minimum and a maximum, which depends on the sky and/or the position of the sun. 
     A preferred embodiment of light-blocking members  6  is shown in FIG.  9 . The profile, reinforced by a horizontal and a vertical rib  37 ,  37 ′ respectively, is approximately semi-circular, subtending an angle of slightly more than 180°. Top surface  38  is substantially planar and is rendered opaque by such known means as painting, coating with an opaque film, or the provision of an opaque plastic layer applied by coextrusion. Top surface  38  is delimited laterally by two bead-like edges  40  which project beyond the semi-circular lower surface  42 . Every 500 to 1000 mm, depending on the total length of cells  4 , the edges  40  are provided with two notches or recesses  44 , one opposite the other, into which are sprung plastic rings  46 . It is these rings that serve as supporting elements which carry members  6  inside cells  4  and that constitute the only contact with the bottom of cell  4 , as is clearly seen in FIG.  10 . The advantage of this kind of mounting of members  6  is the insensitivity of members  6  to the flexure of the panel between purlins, due to snow or wind loads. Up to a surprisingly high degree, such flexures will not interfere with the rotation of members  6 . The ring mounting of members  6  in fact ensures trouble-free operation of panels having a length of 12 meters and more. 
     A variant of the light-blocking member of FIG. 9 is shown in FIG. 11, the difference residing in the fact that the profile portion  45  above the horizontal rib  37  is dovetail-shaped. Another difference is seen in ring  47 , which is now half split, the split portion being provided with legs  48  which abut against surface  38 . The advantage of ring  47 , as compared to ring  46 , is that while rings  46  can be applied only at the ends of member  6  and have to be slid along the latter for a considerable distance (members  6  may be as much as 12 meters long), rings  47  can be opened by elastic deformation and can be quickly snapped into their respective recesses  44  without having to be slid along member  6 . 
     Another embodiment of the light-blocking member  6  is seen in FIG. 12, consisting of a central rod  50  and two vanes  52 . Rod  50  is supported at both ends and vanes  52  rotate inside cell  4 . While for short light-blocking members as required, e.g., in windows or skylights, this embodiment needs supports only at its end, longer members of this type must also be supported at one or more points along their longitudinal extent. 
     A variant of the light-blocking member of FIG. 12 is seen in FIG. 13, in which vanes  52  are not solid, but consisting of narrow strips  54  or even bristles. An arrangement like this would reduce the disturbing effect of panel flexure. 
     Yet another embodiment of light-blocking member  6  is represented in FIG.  14 . The member  6  is in the form of a plastic tube  56  of circular cross-section. About half the circumference of tube  56  is rendered opaque by painting, coating with an opaque film, or the provision of an opaque plastic layer applied by coextrusion. 
     In the following, a detailed description will be given of the mechanism driving light-blocking members  6 . 
     FIG. 15 is an exploded view of the drive mechanism. Power flow is quite simple: motor  8  drives one of a plurality of gears  58  via a coupling  60 A,  60 B. Each one of gears  58  is mounted on the first member  62 A of a 3-member Oldham coupling (a coupling extremely tolerant of lack of alignment between input and output shafts). All gears  58  mesh with a lower rack  64  and an upper rack  64 ′, each of which is slidably seated in grooves  66 ,  66 ′ respectively, provided in lower and upper casing members  12 ,  12 ′ respectively. (Although one rack  64  would do, a pure torque, i.e., a force for rotation without lateral components, requires two racks.) 
     When the gear directly driven by motor  8  rotates, it causes racks  64 ,  64 ′ to slide in opposite directions in their respective grooves  66 ,  66 ′, thereby rotating the rest of gears  58 . Via second coupling member  62 B, first member  62 A rotates third member  62 C, the output end of which is shaped to fit the cavities of light-blocking member  6  and thus rotate the latter. 
     Referring now also to FIG. 16, there is further seen a bearing wall  68  fixedly mounted between lower and upper casing members  12 ,  12 ′ and provided with holes  70  which serve as bearings for the shafts of first coupling members  62 A. Third coupling members  62 C are supported in cells  4  by the first of rings  46 . 
     Also seen is a split wall  72 ,  72 ′ (FIG.  15 ), which, as is clearly seen in FIG. 16, serves to maintain the integrity of each coupling as comprised of members  62 A,  62 B,  62 C by preventing member  62 C from disengaging from member  62 B. The semi-circular recesses  74  do not serve as bearings for collar  76  of third coupling member  62 ; in fact, for the coupling to accommodate unavoidable deviations of alignment, the diameter of recesses  74  must be much larger than the diameter of collar  76 . 
     Further seen in FIG. 15 and, to better advantage, in FIG. 16, are rings  78  which have a slightly tapered bore and, when pushed onto the slotted, slightly tapered hub  80  of gears  58 , clamp the latter onto shaft  82  of gears  58 . 
     Also seen in FIG. 16 are grooves  84  for rubber cords to act as seals when the assembled mechanism is mounted on panel body  2  (see FIG.  1 ). Similar grooves are obviously also provided in the upper casing member  12 ′. 
     FIG. 15 also shows two limit switches  86 ,  86 ′ which define the extremes of the rack movement and, thus, of the rotation of light-blocking members  6 . The limits of this rotation will be discussed further below. It will be appreciated that limit switches  86 ,  86 ′ could also be integral components of gear motor  8 . 
     FIGS. 17 and 18 illustrate another means for rotating the light-blocking members  6 , which means, although conceived for use with the light-blocking member shown in FIG. 12 or  13 , could also be modified for use with the above-described rack and gear mechanism. Using the same spring collet means that served to fixedly mount gears  58  (FIG. 16) on coupling member shaft  82 , levers  88  (FIG. 17) are attached to shafts  50  of vanes  52  in FIG. 12, each lever  88  being provided with a pin  90 . A bar  92  (FIG. 18) with appropriately spaced and sized holes is slipped over all pins  90  and when one of levers  88  is coupled to motor  8 , is rotary motion is transmitted to all levers  88  and thus to all vanes  52 . 
     In the following are discussed the range and control of the rotational movement of light-blocking members  6 . 
     Starting, as schematically shown in FIGS. 19 a - 19   d , from the position of full opacity in which the opaque surface  38  of light-blocking member  6  is substantially parallel to the surface of panel body  2 , member  6  is limited to an angular range of rotation of 90° in both the clockwise and counter-clockwise senses. These limits are enforced by limit switches  86 ,  86 ′ tripped by rack  64  (FIG.  15 ). Setting out from the blocking position (FIG. 19 a ) and rotating in the clockwise sense, surface  38  sweeps a first quadrant of the celestial hemisphere and is stopped by limit switch  86  in the position shown in FIG. 19 b , in which it is perpendicular to the panel surface, i.e., for maximum transmissivity when the sun is at its highest point. In order to sweep the second quadrant, the sense of rotation must be reversed, with member  6  returning and passing through the opaque position (FIG. 19 c ), after which the second quadrant is swept, with member  6  being stopped by limit switch  86 ′. 
     Another embodiment of the panel according to the invention is illustrated in FIGS. 20-28. Panel body  2  is substantially identical with that of the previous embodiment, with cells  4  being of the rectangular type shown in FIG.  6 . Light-blocking members  6  are of the type shown in FIG. 9, but may also be of an alternative design, also shown in FIG.  20 : fully tubular, with an integral diametric partition  39  produced from an opaque plastic material by co-extrusiion with the transparent tubular part. Mounting of panel body  2  on the roof purlins is analogous to the procedure explained in conjunction with the previous embodiment. 
     FIG. 21 illustrates the power flow whereby the rotary movement of an electric motor is transmitted to the light-blocking members. There is seen an electric gear motor  8  which, via two gears  94 ,  96  drives a slotted drive shaft  98  that extends along the entire panel width, as seen in FIG.  22 . Located inside a gearbox  100 , of which there is one for each cell  4 , and keyed to shaft  98 , there is provided a worm  102  engaging a worm gear  104 , equally located in gearbox  100  and keyed to shaft  106  of coupling  108 . The latter constitutes the link between the mechanism described in the aforegoing and the light-blocking member  6 . 
     It will be noticed that coupling  108  is much simpler than the three-member Oldham coupling  62 A,  62 B,  62 C of FIGS. 15,  16  of the previous embodiment. The Oldham coupling, which, as was explained earlier, is extremely tolerant of misalignment between input and output shafts, was needed to take care of the variations, unavoidable in plastic extrusions, of the distances between cells  4 . In the present embodiment, this problem is solved by mounting the one-piece couplings  108  in gearboxes  100  that are rendered “floating” by means of slots  110  which provide them with one degree of freedom in translation along a rail  112 , thus permitting each gearbox  100  and thereby, each coupling  108 , to find its proper position relative to the respective cell  4 . Rail  112  is part of an aluminum profile  114  that accommodates the entire mechanism, including motor  8  attached to profile  114  by means of a bracket  115 . Panel  2  is tightly clamped between profile  114  and another profile that also serves as cover plate  116 . 
     FIGS. 23-26 represent gearbox  100  and its associated components. Seen is worm  102  slidable along, but driven in rotation by, shaft  98  by means of a key  118  (FIG.  23 ). Worm  102  engages worm gear  104 , which is keyed to shaft  106  of coupling  108 . Shaft  106 , as can be seen in FIGS. 23 and 26, is mounted in appropriately located and sized bores  120  in gearbox  100  (FIG.  21 ). Strictly speaking, worm gear  104  should be of the helical type, with the helix angle o its teeth corresponding to the lead angle of worm  102 . While for maximum efficiency and service life, this is indeed the appropriate solution, considering the fact that required speeds are very low and forces are relatively smal, simple spur gears should also do. Since all transmissiion components (except shaft  98 ) are advantageously designed as plastic moldings, extraction, from the mold, of a helical gear would greatly complicate the mold by demanding an additional mechanism to produce the required helical extraction movement. 
     Shaft  106  ends in a flange  122  which is relieved to a depth of about half its thickness for over about three-quarters of its circumference. Into this relieved portion projects a ring segment  124  which is an integral part of gearbox  100  and serves as a stop as well as a reference point for purposes of assembly of the panel unit. Further seen in FIGS. 23,  24 ,  26  and especially in the perspective view of FIG. 27, are drive fingers  126 A, B, C, D which are integral parts of coupling  108  and are configured to enter the spaces defined by ribs  37 ,  37  in FIG.  21  and drive light-blocking members  6  (FIG.  21 ). For use with the cylindrical variant of light-blocking member  6  shown in FIG. 20, the shape of drive fingers  126  must obviously be modified. 
     FIG. 28 is a side view showing the lower end of panel  2 , onto which are clamped profiles  114  and  116  which, between them, accommodate the entire mechanism, including motor  8 . Waterproofing is ensured by means of a seal  128  located in a groove in cover plate  116  and extending along the entire width of panel  2 . 
     This embodiment, too, may have limit switches defining limit positions, with the switch body attached to a stationary part of the mechanism, and the switch being tripped by a moving part thereof. 
     Obviously, light-blocking members  6  can be stopped at any angular position, also between the limit positions defined by the limit switches, by controlling member  8 . This can be done either manually or automatically. Manual control is effected by operating a spring-loaded, polarity-reversing pushbutton. Also required is a power supply including a voltage stabilizer and a thermal fuse to protect motors  8 . To obtain satisfactory automatic control, it is best to use a stepping motor controlled by a microprocessor working with a program including all parameters involved in the proper operation of the panels, such as limits of rotation in the clockwise and counter-clockwise senses (thereby eliminating the need for limit switches), opening of light-blocking members  6  as a function of the prevailing light as sensed by photodetectors, dimming of artificial illumination in dependence of natural light entering through the panels, stopping motors in case of overload, etc. 
     Clearly, the user can always override the program or introduce whatever changes are desired. The program can also be designed to switch off the system on weekends or during vacations. 
     The panel according to the invention will operate in all positions: horizontal, vertical, slanted, even slightly arched. 
     While the above-described drives are indeed preferred, other types of drives are also possible, e.g., chain or timing-belt drives. 
     Although in the foregoing the term “manual” was meant to refer to the manual activation of gear motor  8 , it will be appreciated that embodiments are envisaged in which the panel according to the invention, instead of, or in addition to, being driven by the gear motor, can also be operated manually.