Abstract:
The invention provides a panel unit of controllable radiation transmissivity, including a housing constituted by a front, radiation-receiving panel and a rear panel, the panels being spaced apart and connected to one another by connecting means; a plurality of rotatable radiation-blocking members disposed between the front panel and the rear panel, the members being rotatable from one angular position in which the radiation-blocking members are adapted to substantially block the passage of light through the panel unit, to a selectable plurality of other angular positions in which the radiation-blocking members are adapted to provide a plurality of differing radiation transmissivities; characterized in that first guiding surfaces for the rotatable radiation-blocking members are disposed inside of, and extend across, the housing.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a panel unit of controllable radiation transmissivity for the construction of walls, roofs, awnings, skylights, windows, and the like. 
   BACKGROUND OF THE INVENTION 
   Israel Patent Application No. 124,949 teaches a panel which comprises a plurality of rotatable members having an opaque surface, which members, when rotated, are adapted, in at least one angular position, to substantially block the passage of light through the panel, and, in a plurality of other, selectable angular positions, to provide a plurality of differing radiation transmissivities. 
   While the above-mentioned panel does indeed provide a steplessly adjustable light transmissivity, it has certain disadvantages, inasmuch as the rotatable light-blocking members are accommodated in an array of tubular cells of relatively large size and wall thickness, that add to the costs of these panels. 
   DISCLOSURE OF THE INVENTION 
   It is an object of the present invention to ameliorate the disadvantages of the prior art light-blocking panels and to provide a panel unit having controllable radiation transmissivity facilitating substantially the complete blocking of radiation. 
   The invention therefore provides a panel unit of controllable radiation transmissivity, comprising a housing constituted by a front, radiation-receiving panel and a rear panel, said panels being spaced apart and connected to one another by connecting means; a plurality of rotatable radiation-blocking members disposed between said front panel and said rear panel, said members being rotatable from one angular position in which said radiation-blocking members are adapted to substantially block the passage of light through said panel unit, to a selectable plurality of other angular positions in which said radiation-blocking members are adapted to provide a plurality of differing radiation transmissivities; characterized in that first guiding surfaces for said rotatable radiation-blocking members are disposed inside of, and extend across, said housing. 

   
     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 an exploded view of the panel unit according to the present invention; 
       FIG. 2  is an end view of the panel unit of  FIG. 1 , without the drive mechanism and its housing; 
       FIG. 3  is a perspective view, in partial cross-section and to a larger scale, of the rotatable radiation-blocking member; 
       FIGS. 4–6  illustrate variants of the radiation-blocking member; 
       FIG. 7  represents the general shape and location of the lower cross-members; 
       FIG. 8  indicates the shape and location of the upper cross-member to a larger scale; 
       FIG. 9  is an exploded view of part of the drive mechanism; 
       FIG. 10  is a partial top view of the cross-member accommodating the drive mechanism; 
       FIG. 11  is a side view of the components shown in  FIG. 10 ; 
       FIG. 12  illustrates the components of the gearbox of  FIGS. 10 and 11 ; 
       FIG. 13  illustrates the fully encased gearbox, and 
       FIG. 14  is an end view of another embodiment of a panel unit according to the invention. 
   

   DETAILED DESCRIPTION 
   Referring now to the drawings,  FIG. 1  illustrates a radiation-receiving front panel  2 , a rear panel  2 ′ and two lateral connecting members  4 ,  4 ′ which, in assembly, constitute the housing of the panel unit according to the present invention. These components are seen to better effect in  FIG. 2  and will be explained in detail further below. 
   Further seen in  FIG. 1  is a battery of rotatable radiation-blocking members  6  disposed between front panel  2  and rear panel  2 ′. This central component of the panel unit is shown to a larger scale in  FIGS. 2 and 3 , and will be discussed in conjunction with these Figures. The radiation-blocking members  6  are supported by lower cross-members  8  of which, in the panel of  FIG. 1 , there are three, resting, in assembly, on rear panel  2 ′. The number of these cross-members obviously depends on the actual length of the panel unit. Also seen are upper cross-members  9 , in assembly, substantially co-planar with, but above, the lower cross-members  8 . Both the upper and lower cross-members will be discussed further below in conjunction with  FIGS. 2 ,  4  and  5 . Cross-members  8  and  9  are shown to better effect in  FIGS. 4 and 5 , respectively. 
     FIG. 1  also illustrates the drive mechanism, which includes an electric motor  10  coupled to a reduction gear  12  that drives the radiation-blocking members  6  via gearboxes  14 , each member having its own gearbox  14 . Cross-member  16 , advantageously made of an aluminum extrusion, serves as housing for the drive mechanism and also closes off the front end of the panel unit. Cross-member  16 , as well as the drive mechanism, is covered by a cover plate  18 . 
   Supporting rings  20 , their purpose and the manner of their mounting, are discussed below in conjunction with  FIGS. 2 and 3 . 
     FIG. 2  is a fragmented end view of the assembled panel unit, but without the drive mechanism and its housing. There are seen front panel  2  and rear panel  2 ′, two substantially identical plastic extrusions, advantageously made of polycarbonate. Each panel consists of two spaced-apart plane sheets interconnected by ribs  22 ,  22 ′, which provide mechanical strength and define air spaces for thermal and acoustic insulation. Each panel is also provided with flanges  24  on each of its lateral edges. The inside surface of each flange  24  is comprised of sawtooth-like barbs  26 , which are adapted to engage and lock against similarly shaped barbs  28  in a lateral, substantially H-shaped, connecting member  30 . The latter is advantageously made of an aluminum extrusion and connects not only the front and rear panels of a single panel unit, but also, as is clearly shown, constitutes the connecting member of adjacent panel units. Member  30  is furthermore provided with a number of rail-like ledges  32 ,  34 ,  36  and  32 ′,  34 ′,  36 ′, the purpose of which will become apparent further below. 
   It will be appreciated that, the above notwithstanding, the panels could also be single-plane sheets or even glass sheets, and that the panels could be connected at their front and rear ends, rather than laterally. 
   Inside the space defined by front panel  2 , rear panel  2 ′ and connecting members  30  ( FIG. 2 ), there are located a plurality of rotatable, radiation-blocking members  6 , supporting rings  20  for members  6 , lower cross-member  8  and upper cross-member  9 . 
   Radiation-blocking member  6 , shown to better effect in  FIG. 3 , is a tubular, generally transparent, plastic extrusion with a profile advantageously reinforced by horizontal and vertical ribs  38 ,  38 ′ respectively, and is approximately semi-cylindrical, subtending an angle of about 180°. The top surface of member  6  is substantially plane and is rendered opaque (hereinafter “opaque plane  40 ”) by such known means as painting, coating with an opaque film, or the provision of an opaque plastic layer applied by coextrusion. Edges  42 ,  42 ′ of member  6  extend beyond the largest width of the semi-circular profile, edge  42  being coplanar with top surface  40 , while edge  42 ′ is stepped down to a depth equaling the thickness of protruding edge  42 , so that, in the blocking position represented in  FIG. 2 , the two edges overlap and also provide abutment surfaces. 
   Supporting rings  20  are made of a plastic material and are thin enough to be elastically deformable, having an inside diameter substantially identical with the outside diameter of the semi-circular profile, and are sprung into pairs of recesses  44 ,  44 ′ provided in edges  42 ,  42 ′ at appropriate distances, depending on the total length of the panel unit. 
   Rings  20  are in turn supported by lower cross-member  8 , which has the form of an extruded plastic T-profile that rests on rear panel  2 ′ and is held in position by ledges  32 ,  32 ′ of connecting members  4 . The vertical web  46  of cross-member  8  is provided with preferably cylindrical recesses  48 , of a curvature slightly smaller than the outside curvature of rings  20 , so that the latter have only line contact with recesses  48 . 
   Further envisaged variants of radiation-blocking member  6  are illustrated in  FIGS. 4–6 .  FIG. 4  shows a first of such variants, in the form of a tubular, fully cylindrical portion  7  consisting of a transparent plastic extrusion and comprising a diametrical, substantially opaque planar partition  41 , co-extruded with the cylindrical portion  7 , but made of an opaque plastic. 
     FIG. 5  illustrates another cylindrical variant of radiation-blocking member  6 , in which the transparent, tubular, cylindrical portion  7  is provided with two diametrically opposite pairs of inward-pointing, short flanges  11 ,  11 ′, defining between the partners of each pair a slot, into which is slid an opaque strip  43 , either of plastic or metal. 
     FIG. 6  illustrates a further variant of radiation-blocking member  6 , seen to consist of two transparent, substantially half-cylindrical portions  13 ,  13 ′ and a substantially planar, diametrical, opaque partition  41 . The two half-cylindrical portions  13 ,  13 ′ are laterally mutually offset, producing a left overhang  15  and a right overhang  17 . It is seen that the right overhang  17  is stepped down, so that in the blocking position shown in  FIG. 6 , overhangs  15  and  17  overlap and also constitute abutment surfaces, with all opaque surfaces being rendered co-planar. 
   The variants of  FIGS. 4–6  do not require the use of rings  20  and are therefore in direct contact with recesses  48  in cross-member  8 . 
   Another solution could be in the form of a flat, elongated strip with a zebra-like cross-section, looking as if cross-hatched, in which transparent stripes alternate with opaque stripes. Such a strip could offer maximal transmissivity at a certain angle of incidence, and substantial opacity at another angle of incidence. 
     FIG. 7  illustrates the general shape and location of lower cross-member  8  with respect to lower panel  2 ′. 
   Upper cross-member  9 , seen in  FIG. 2  and, to better effect, in the perspective drawing of  FIG. 8 , has the task of substantially maintaining the contact between radiation-blocking members  6  and their rings  20  with the curved recesses of lower cross-member  8 , but without causing additional friction when members  6  are rotated. This is achieved by providing a small gap a between rings  20  and the lower surface of upper cross-member  9 , as clearly seen in  FIG. 2 . Cross-member  9 , a U-profile advantageously produced by extrusion (see also  FIG. 8 ) is located above rings  20  and is held in this position by ledges  34 ,  36  of connecting member  4 . 
   As mentioned above,  FIG. 2  represents the state of maximum opacity of the panel unit. Radiation transmissivity increases when, relating to  FIG. 2 , radiation-blocking members  6  are rotated in the clockwise sense, with transmissivity becoming maximal when the opaque plane  40  ( FIG. 3 ) is rotated into a position where it offers the least surface area to the sun or the brightest part of the sky. 
     FIG. 9  represents an exploded view of part of the drive mechanism, including cross-member  16  which accommodates the entire mechanism, motor  10 , advantageously a stepping motor, manually and/or electronically controlled, depending upon light conditions sensed by a photodetector. Further seen are reduction gear  12  and slotted shaft  50 , extending over the entire width of the unit. A gear  52 , meshing with the output gear  54  of reduction gear  12 , is keyed to shaft  50 . Also seen are two posts  56 , whereby the motor-gearbox unit is attached to cross-member  16 . Partly shown is the first of cross-members  8 , which defines the respective positions of gearboxes  14  ( FIG. 10 ). 
   Shown in the top view of  FIG. 10  are gearboxes  14 , which, as will be seen in  FIGS. 12 and 13 , are in fact worm gears, all of which are keyed to and are driven by shaft  50 . The worm wheels are keyed to coupling members  58 , being the output members of gearboxes  14 . Coupling members  58  are provided with shaped projections, part of which fit the spaces created by reinforcing ribs  38 ,  38 ′ of radiation-blocking members  6 , thus constituting the drivers of members  6 . 
   In the side view of  FIG. 11 , there are shown extruded cross-member  16 , reduction gear  12 , a second vertical member  60  of the extrusion, a low rail  62  that is an integral part of the extrusion, the first of the three cross-members  8  that, in the embodiment of  FIG. 1 , support the radiation-blocking members  6 , and coupling member  58 . 
   Gearbox  14 , to be discussed in greater detail below with reference to  FIGS. 12 and 13 , is positioned between vertical member  60  and rail  62 , but has one degree of freedom in translation in a direction perpendicular to the paper, which enables it to align itself with radiation-blocking members  6 , the positions of which are defined by the recesses in webs  46  of cross-member  8 . 
     FIG. 12  illustrates the components accommodated in gearbox  14  of  FIGS. 10 and 11 , already defined as a worm gear. Worm  64  is keyed to shaft  50  by means of key  65 , but has one degree of freedom in translation in the axial direction of shaft  50 . Worm  64  meshes with worm wheel  66 , which, in turn, is keyed to axle  68  of coupling member  58 ; thus, rotation of shaft  50  will produce a rotation (at reduced speed) of coupling member  58 . 
   Axle  68  ends in a flange  70 , from which project drive fingers  72 A,  72 B,  72 C and  72 D. Of these fingers,  72 A and  72 B fit, and thus can be slipped into, the two spaces produced in radiation-blocking members  6  below horizontal reinforcing rib  38  ( FIG. 3 ), and fingers  72 C and  72 D come to rest on opaque plane  40  of member  6 . 
   Further seen are two elastic fingers  74  which, at their ends, carry cupped projections  76 . These projections are designed to be snapped into two holes (not shown) of appropriate size and location near the end of each radiation-blocking member  6 , thus constituting a positive link between members  6  and coupling members  58 . 
     FIG. 13  represents the fully encased gearbox  14 . There is also seen an annular segment  78 , integral with the casing and subtending a defined angle which is configured to cooperate with a similar segment (not shown) integral with flange  70 , which segments constitute a stop and also serve as reference points for the proper assembly of the panel unit. 
     FIG. 14  illustrates another embodiment of the invention which dispenses with the separate, H-shaped connecting members  30  of  FIG. 2  by providing each of the panels with a relatively short, slender flange  24 , such as shown in  FIG. 2 , and a longer and heavier flange  80 , the lower end of which is configured to constitute a connecting member in the form of a female counterpart to flange  24 . The sawtooth-like barbs  28  of flange  24  are adapted to engage and interlock with similarly shaped barbs  82  within the end portion of flange  80 . 
   While it would, of course, be possible to provide one of panels  2 ,  2 ′ with two flanges  24  and the other one with two flanges  80 , the advantage of the design illustrated in  FIG. 14  resides in the fact that the same extruded profile can be used for front panel  2  and, simply turned around, also for rear panel  2 ′. 
   Cross members  8 ,  9  are fixedly attached to their respective panels, e.g., by cementing. 
   It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrated embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.