Abstract:
A Venetian blind is accommodated within the sealed interspace defined by the two glass surfaces of a glass-box including two or more glass surfaces spaced apart by an aluminum frame which contains the molecular sieve. The Venetian blind is provided with control members which allow adjustment of packing and/or inclination of its blades from outside the glass-box without altering the seal, and therefore the functionality, of the same. Operation from the outside of the control members inside the glass-box is achieved, for each adjustment, by magnetic coupling, through one of the glass surfaces of the glass-box, between a first magnet, positioned inside the glass-box and directly connected to the respective control system, and a second external magnet.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a multiple blade curtain, in particular a Venetian blind. 
     The problems which arise in using a Venetian blind installed on a window are known; among them, the most evident reside in the fact that such blinds require frequent cleaning operations and are often subject to accidental damage. 
     In order to overcome these problems, two kinds of solutions are mostly used at present: a first solution consists of accomodating the Venetian blind between two separate window-frames; the second entails the use of a single frame with double shutters, inside which the Venetian blind is inserted. 
     However, both these solutions present some disadvantages and inconveniences, such as a high cost and a considerable weight, as well as the fact that, since the accomodation is not hermetic, dust and condensed fumes can still deposit on the slats, thus requiring frequent cleaning operations which can cause damage to the blades. Conversely, since very frequent cleaning (or washing) cannot be performed, the aesthetical aspect of the blind is obviously compromised. 
     It should be furthermore noted that such known solutions also entail large dimensions and restrict the use of the product. 
     SUMMARY OF THE INVENTION 
     The main aim of the present invention is to eliminate the above described disadvantages of known Venetian blinds, by devising a blind which, by virtue of its peculiar characteristics, after being installed is not subject either to becoming dirty or to the possibility of accidental damage, so as to completely eliminate the need for cleaning or maintenance operations. 
     Within this aim, a particular object of the invention is to provide a Venetian blind which can be accommodated in a hermetical seat and nevertheless is provided with an operation system which allows a rapid and functional adjustment of packing and inclination of the blades, without jeopardizing tighteness of the accomodation. 
     Not least object is to devise a Venetian blind or the like having an accomodation with a very simplified structure, which can be easily obtained starting from commonly available elements, furthermore the Venetian blind should be able to have very small dimensions to allow a wide utilization. 
     The above aim and objects as well as others which will become apparent hereinafter, are achieved, according to the invention, by a Venetian blind characterized in that it is accommodated in the sealed interspace defined between two glass surfaces of a glass-box, said blind being provided with first control means for the adjustment of the inclination of the slats and second control means for the adjustment of the accumulator of the slats, said first and said second control means comprising first magnet which is movable inside said interspace and can be operated, by means of a magnetic coupling through one of said glass surfaces, by a second magnet, located outside said glass-box, said second control means comprising automatically variable counterwight means for maintaining the force required for accumulation of the slats at a constant minimum value. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features and advantages of the invention will become apparent from the description of a preferred, but not exclusive, embodiment of a Venetian blind, according to the invention, illustrated only by way of non-limitative example in the accompanying drawing, where: 
     FIG. 1 is a front view of the entire Venetian blind; 
     FIG. 2 is a view of a peripheral portion of the blind of FIG. 1, illustrating the blade inclination control means; 
     FIG. 3 is a side view, in enlarged scale, of a detail of the control means shown in FIG. 2; 
     FIG. 4 is a view of a peripheral portion, opposite to the portion of FIG. 2, illustrating the blade packing control means; 
     FIG. 5 is a side view, in enlarged scale, of a detail illustrating the magnetic coupling for blade packing adjusting; and 
     FIG. 6 is a cross section view, in enlarged scale, along line VI--VI of FIG. 4, where the position of the upright of the window-frame has been indicated schematically by a broken line. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the figures, a Venetian blind according to the invention, generally indicated at 1, comprises a plurality of blades 2 forming blind slats and connected to the upper side 3 of a perimetral frame 4, suitably formed, as is better illustrated in FIG. 6, of a C-shaped profile having a thickness which is approximately the same as the inner interspace 5 of a glass-box 6 accomodating the frame 4. 
     This glass-box 6, as is known, essentially comprises of a pair of glass surfaces, respectively outer 7 and inner 8, kept spaced apart from one another by an aluminum framework 9 which contains a molecular sieve 10 and is sealingly connected to the glass surfaces by means of sealing elements 11. 
     The Venetian blind 1 is provided with slats inclination adjustment means which, as is better illustrated in FIG. 2, comprise a shaft 12, of a usual kind, extending inside the upper side 3 and bearing, rigidly connected thereto, supports 13 for winding thereon small cables 14 which, through their vertical motion, rotate all the blades 2 in a synchronized manner about a blade longitudinal axis. 
     According to the invention, the shaft 12 receives its motion from a second rotating shaft 15, which extends within a first side portion 16 of the frame 4, through an angular return transmission suitably comprising a toothed wheel 17 keyed onto the shaft 12 and meshing with an endless screw 18 provided in the upper end 19 of the second shaft 15. The second shaft 15 is internally threaded and, at its lower end 20, is engaged by a complementarily shaped helical rod-like element 21, with a suitable pitch, which bears, downwardly rigidly connected therewith, a first inner magnet 22. 
     This inner magnet 22 is associated with a second outer magnet 23, which is separated therefrom by the inner glass surface 8, so that by means of the magnetic connection therebetween it is possible to control rotation of the slats 2 from the outside. 
     Indeed, when the first external magnet 23 is moved vertically, it causes an equal movement of the inner magnet 22, and thus of the helical rod-like element 21, so that the second shaft 15 and therefore the first shaft 12 are caused to rotate in the desired direction. 
     It is thus evident that by moving the outer magnet 23 the desired orientation of the Venetian blind is achieved between a maximum darkening, at the two ends of the stroke, and a partial darkening at an intermediate level. 
     The Venetian blind 1 furthermore comprises control means which allow packing of the blinds 2 and therefore vertical extension of the blind to be varied from a total extension thereof, which corresponds to a complete darkening, up to the complete lifting, which corresponds to a full view. 
     Now with particular reference to FIGS. 4 and 5, the packing control means comprises a pair of cables 24 and 25 which are connected on one side to a rigid rod 26 which is located at the base of the blades 2 and which, after being wound on the respective guide or return pulleys 27 and 28, and on an idle roller 29, extend inside a second side portion 30 of the perimetral frame 4, connecting at the other end to an inner slider 31, suitably composed of two magnets 32 rigidly fixed to a metallic plate 33. 
     According to the invention, the inner slider 31 is magnetically connected, through the inner glass surface 8, to an outer slider 34 which is also advantageously formed by a pair of outer magnets 35 joined to a metallic bracket 36. 
     The stroke of the sliders 31 and 34 must be equal to the maximum extension of the blind 1, so that the motion of the inner slider 31, imparted from outside the glass-box 6 by means of a corresponding vertical motion of the outer slider 34, acting by means of the pair of cables 24 and 25, causes lifting or lowering of the rigid rod 26, accordingly varying the extension of the blind 1. 
     It should be pointed out that, for example during lifting of the rigid rod 26, more and more blades 2 gradually rest on it, starting from the lower ones; for this reason, the weight which must be lifted by means of the cables 24 and 25 depends on the extension of the blind 1 and, precisely, increases as the rigid rod 26 rises. 
     In other words, when the rod 26 is completely lowered the lifting force is mininal, while when the rod 26 is almost completely raised the force required for a further ascending motion is much greater. 
     To solve this problem, a counterweight is used, the action whereof depends on the position of the rigid rod 26, so as to keep constant the effort required to raise the Venetian blind 1. 
     According to the invention, the counterweight suitably comprises a track 37 which, connected at one first end 38 thereof to the inner slider 31, winds around the upper idle roller 29 and has the opposite end 39 connected to a return cable 40 which, by winding on a lower idle roller 41, is in turn connected to the inner slider 31. 
     For the sake of descriptive completeness, it should be furthermore observed that, in order to achieve optimum system balancing, it is appropriate for the weight of the inner slider 31 to be equal to the sum of the weight of the rigid rod 26 and of half the weight of all the blades 2, reaching this value with a possible addition of ballast; in this case the track 37 will have a length equal to the entire extension of the blind 1 and a weight equal to half the weight of all the blades 2. 
     In this manner, the system is exactly balanced in every position, and the sliders 31 and 34 may be placed at any intermediate level, with the blind 1 keeping the corresponding thus set extension. 
     In practice, it has been observed that a Venetian blind according to the invention presents remarkable advantages with respect to other known solutions, since dust is absolutely prevented from entering the interspace 5, due to the latter remaining perfectly sealed, and the blades 2 are permanent clean, thus eliminating the need for any subsequent cleaning operation. 
     The installation inside the glass-box 6 furthermore avoids that accidental deformations or breakages of the blades 2 may occur, and this, together with the foregoing, ensures a perfect unalterability of the Venetian blind 1 in time. 
     It should be furthermore observed that with a blind according to the invention the overall dimensions are reduced to a minimum and the weight is also consequently smaller, thus increasing the possible utilizations of the Venetian blind according to the invention. 
     A further advantage is determined by a low cost of installation, since with a single operation for fitting the glass-box, a Venetian blind is also simultaneously installed, thus eliminating the cost of a subsequent second fitting. 
     The costs can be reduced further by taking into account the fact that the use of a window-frame with a glass-box accommodating therein a Venetian blind according to the invention allows elimination of the outer blinds of the windows. 
     The invention thus conceived is susceptible to numerous modifications and variations, all of which are within the scope of the inventive concept. 
     Thus, for example, the shape of the perimetral frame 4 may vary; the helical rod-like element 21 may be replaced by a helical thin plate; the outer face of the glass surface 8 may be provided with any guiding elements slidably engaged by the outer magnet 23 and/or the outer slider 34; the structure of the track 37 may be any, so long as the indispensable balance relationships are respected, and moreover, the motion transmission between the magnets may be non-linear, but also, for example, of a rotary type, so long as the internal control means for adjusting the Venetian blind may be operated without direct physical contact. 
     Furthermore, in practice, the materials employed, so long as compatible with the contingent use, as well as the dimensions, may be any according to the requirements and to the state of the art.