CA1117861A - Concertina-foldable framed closure - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE:

An improved mechanically operated concertina-foldable frame closure comprises a frame including first and second parallel sections each having guide means; a plurality of elongated flat elements separated by elongated jointing elements, each flat element being hinged to its two adjacent jointing elements along respective and adjacent lateral edges;
and support means fixed to alternate jointing elements at both ends thereof and slidably engaged in the guide means of the first and second frame sections. At least one endless chain is arranged inside the frame so as to define two coplanar chain portions in each of the first and second frame sections, each chain portion being guided at each corner of the frame by a respective idler wheel for movement of the chain portions in each frame section in opposite directions; at least one alternate jointing element is connected at one end thereof to one chain portion in the first frame section and, at the other end thereof, to another chain portion in the second frame section moving in the same direction as the one chain portion. A
sprocket wheel located in one of the corners engages each endless chain so as to cause the one chain portion and the other chain portion to move in one direction or the opposite, thereby causing the alternate jointing elements to move towards or away from one another to respectively open or close the framed closure. The framed closure of the invention is particularly suitable for use as blind or shutter for windows, doors, french windows and the like.

Description

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The present inven-tion relates to a mechanically operated concertina-foldable framed closure, such as blinds or shutters for windows, doors or french windows.
Foldable blinds or shutters for windows, doors or french windows are known, consisting substantially of a plurality of vertical f lat elements disposed side-by-side and hinged to each other, and which are suspended and guided between suitable horizontal straight guides in such a manner as to be able to be extended in a plane or folded back on to each other.
In said blinds the mutual hinging points between the various component section elements are generally disposed symme-trically about their thickness, or at two opposing corners along a diagonal of the elements. These hinging points also alter-nately comprise the means for engaging with the suspension and guide rails.
Known blinds or shutters conceived in the aforesaid manner may be divided into two types according to the arrange-ment of their constituent modular elements when they are completely extended i.e. when the window, door or french window space is covered. When in the extended position, the modular elements of the first type are mutually aligned to form a flat wall, while the elements of the second type converge to form a zig zag line. Both said types of blind have disadvantages which are mainly of operational, constructional and a esthetic character.
The first said type of blind presen-ts difficulties in folding up its component elements, necessary for uncovering the opening on which the blind is located, because of jamming between the elements due to the fact that as they are aligned and stressed by a force acting along their direction of align-ment, they are not subjected to any component normal to the plane of the blind.

,''' - 1 -An attempt has been made -to overcome this by usiny complicated supplemen-tary guides or lead-ins which, in combi-nation with suitable contact pieces fitted to said modular elements, aid their misaliynment so preventing said jamming.
It has however been necessary to provide a certain degree of slippage for the blind in order to allow contact between said contact pieces and said supplementary guides.
As is apparent, this type of blind does not give the necessary guarantee of operation, and at the same time is 19 easily subject to breakage, is of complicated construction and assembly because of the large number of pieces, and is also very noisy during use.
The second type of blind, while not presenting excessive difficulty in folding, is unattractive and favours the introduction of atmospheric deposits and/or impurities and water, especially in the lower guide, which can compromise its proper operation.
The object of the present invention is to obviate the said disadvantages by providing an improved concertina-foldable blind or shutter which, although of simple and func-tional construction, arranges itself automatically in a plane when extended and presents no difficul-ty in folding up, without using supplementary guides or other linkages for preventing said undesirable and damaging jamming. Moreover, the blind according to the invention is provided with a mechanical device for its opening and closing movement, such a device never having been provided in the case of blinds of known type.
According to the present invention there is provided an improved mechanically operated concertina-foldable frame closure, which comprises: a frame including first and second parallel sections each having guide means; a plurality of elongated flat elements separated by elongated jointing elements, each flat element being hinged -to its two adjacent jointing elements along respective and adjacent lateral edged; support means fixed to alternate jointing elements at both ends thereof and slidably engaged in said guide means of said first and second frame sections; at least one endless chain arranged inside said frame so as to define two coplanar chain portions in each of said first and second frame sections, each chain portion being guided at each corner of said frame by a respec-tive idler wheel for movement of the chain portions in each frame section in opposite directions, at least one alternate jointing element being connected at one end thereof to one chain portion in said first frame section and, at the other end thereof, to ano-ther chain portion in said second frame section moving in the same direction as said one chain portion;
and a sprocket wheel located in one of said corners and engaging each endless chain so as to cause said one chain portion and said other chain portion to move in one direction or the opposite, thereby causing said alternate jointing elements to move towards or away from one another to respectively open or close said framed closure.
According to a preferred embodiment, the hinges between the flat elements and the jointing elements are cons-tituted by a pair of conjugate projections of curled cross-section, and.mutually copenetrating.
Alternatively, the hinges between the flat elements and jointing elements may comprise a. double series of spaced-apart aligned sleeves joined by a single central pivot in -the form of a rod.
In a particularly preferred embodiment, the jointing elements are constitued by a hollow section adapted to receive at each end thereof a shank on which is mounted an end plate extending in width beyond the lateral edge of the section.

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In such an instance, the support means may comprise a slide plate extending from alternate end plates and adapted to slide ln upper and lower guide portions of the frame.
The chain is preferably connected to the last alter-nate jointing element by means of an appendix which extends from the shank at each end of this jointing element and engages in the chain lin};s.
The framed closure of the invention may be operated by a single chain, but a two-chain drive system is preferred.
The sprocket wheel which drives the chain or chains can be operated either manually or by an electric motor, or by any other equivalent means.
Preferred embodiments of the invention will now be describedin greater detail with reference to the appended drawings, in which -~ igure 1 is a partial perspective view of a framedclosure of the invention showing the support means;

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Figure 2 is a partial perspective view of the intermediate jointing element showing the means for locking the end plugs;
Figure 3 is a plan view of a portion of the framed closure in two differen-t operating positions;
Figure 4 is a partial perspective view of an alterna-tive embodiment of the framed closure;
Figure 5 is a partially sectional frontal view of the completely extended framed closure, complete with operating device;

Figure 6 is a plan view of the horizontal section of Figure 5 with the framed closure completely extended and in the folding state (shown by dashes with two points);
Figure 7 is a partial perspective view of a portion of framed closure showing the type of connection between the support and guide means and one of the drive chains;
Figure 8 shows the drive means for the chains;
Figure 9 is a section on the line IX-IX of Figure 8;
Figure 10 is a cross section through the upper and lower horizontal frame sections which act as guides both for the shutter support means and for the horizontal portions of the chains;
Figure 11 is a diagrammatic representation of the drive device with a double wing and single wing shutter;

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Figure 12 is a diagram showing an alternative design of the operating device with a single chain for a single or dou-ble wing shutter;
Figure 13 is a diagrammatic illustration of a further alternative embodiment of the drive device.
For clarity of drawing and for easier understanding of the constructional and operational characteristics of the blind or shutter according to the invention, this latter is illustrated in Figures l to 4 in the two proposed designs without the operat-ing device, this latter being shown in detail in the remaining fi-gures applied to only one of the proposed blind designs.
~ ith particular reference to Figures l to 3, the blind consists of a set of substantially parallelepiped hollow panels l, the outer surfaces of which comprise opposing vertical grooves of substantially triangular cross-section 2 at which there are provided suitable internal stiffening baffles 3.
Each individual panel l is connected to the subsequent or preceding panel by way of a suitable intermediate jointing element 4. Said element 4 consists essentially of an extruded section preferably of the same material as the element 1, its cross-section comprising centrally a bore 5 substantially configur-ed as a sector of a circular crown, the internal contour of which degenerates into a straight line, while the external contour extends in the form of two suitable symmetrical spirals 6 of oppo-site curvakure to the curvature of said external contour.
At a convenient distance from the upper edge and lower edge these intermediate elements 4 comprise two suitable substan-tiall~ rectangular slots 7.
The lateral edges of the panels l are con~igured as suitable spirally curled portions 8 to obtain a surface conjugate with the surface of the spirals 6 of the intermediate sectors 4.
Said curled portions 8 are symmetrical and opposite about the F.~
central axis of the panel. The connection between the intermedia~e element 4 and panels 1 is made by axially inserting the spirals 8 of the panels 1 into the spirals 6 of said sector 4.
The spirals 8 branching from the edges of panels 1 are in opposite positions relative to the depth of the panels so that the intermediate sectors 4 can be mounted alternately in two opposing position.
Into the bore 5 present in the intermediate sector 4 (see Fig. 2) there is pressed a shank 10 the cross-section of which coincides substantially with the cross-section of said bore 5, said shank being inserted until the two suitable teeth 11 branch-ing therefrom snap into the slots 7 contained in the surfaces of the bore 5.
The presence of the slots 7 and teeth 11 are not indis-pensable for fixing the shank 10 into the bore 5 of each intQrme-diate sector 4, as said fixing may be obtained in different ways, for example by a suitable adhesive or rivets.
Above said shank 10 there is a plate 12 which rests on the upper or lower edge of the intermediate sector 4 and on the ends of the upper or lower edges o~ the two panels 1 connected thereto.
A device 10-12 composed in this way is inserted into the bore 5 of each of those intermediate sector 4 intended to move out of the vertical plane defined by the two upper and lower guides, while into the intermediate sectors 4 intended to remain or slide within said plane there are inserted (see ~ig. 1) devices 10-12 which, besides the shank 10 and plate 12, also comprise a sho~t cylindrical or prismatic portion 13 connected to the plate and terminating in a preferably square or rectangular plate 14 parallel to the underlying plate 12 and which seats in the upper or lower straight guide 15.
Said upper and lower straight guides 15 are substantially t ~ ~'7~

constituted by an extruded section of convenient material, compris~
ing two longitudinal adjacent channels 15' and 15" of which the channel 15' comprises in its lower wall a slot 16 constituting a sliding lane for the prismatic portion 13 of ~e s~spension and guide devices 10-12 for the screen. The outer wall of the channel 15" extends on the same side as said slot 16 by a portion 155 which branches in the form of two shelves, orthogonal to said portion, one of which is an end shelf 15a and the other an intermediate shelf 15b.
As stated, Figure 3 illustrates diagrammatically the arrangement assumed by the component elements 1 and 4 of the blind according to the invention, in two different positions.
j The position indicated by the heavy continuous line is that which the various component elements 1 and 4 take during partial concertina folding of the blind, while the position indicat-ed by the thin broken line is that taken by the same elements when the blind is completely extended, i.e. with the elements perfectly aligned to form a flat wall.
From said figure it is evident that passage from the extended position to the folded position and vice versa occurs without any jamming of the blind elements because of the presence of the intermedia e elements .
In this respect, on exerting a slight pressure on the extended blind, moment~ are generated because of the arm existing between the two lines of hinging, and these cause the intermediate sectors 4 not connected to the guide 15 to move outwards, and drag the panels 1 hinged to them~
The plates 14 slide in the channel 16 of the guide 15 until the various panels 1 are completely concertina folded and rest one against the other.
Said configuration is made possible by the fact that the cylindrical surface of the intermediate sectors 4 lodges in suitable vertical curved recesses 9 provided in the lateral ed~es ,"~ ,, O
, ~,,, , ,,,, 6~
of the panels 1.
In moving the blind from the folded to the extended po-sition, the component elements 1 and 4, on being pulled, behave in a manner exactly opposite to that described for the reverse movement heretofore specified.
A possible alternative embodiment of the blind or shutter according to the invention is shown in Figu~e 4, in which the connection between the intermediate sector 4 and side panQls 1 is made with a normal hinged joint of the type commonly used for the doors of wardrobes. Said figure shows that the intermediate sector 4 is substantially constituted by an extruded section of substantially rectangular cross-section, the lateral edges of which support small opposing bored cylinders 17 of convenient length spaced apart by a distance substantially equal to the ~ength of said cylinders 17.
The bored cylinders 18 supported by the lateral edges of the panel 1 are located between the cylinders 17 supported by the intermediate sector 4. Said sector 4 and the panels 1 are connected by inserting a wire 19 of ~teel or a suitable synthetic material, and of suitable length, into the through bores 20 coaxial to the cylinders 17 and 180 The ends o~ said wires are housed in suitable flared holes 21 provided in the plate 12, and are suitably riveted on said plate~l2.
~ he composition of the blind according to the invention of both the proposed designs is more evident from Figures 5 to 10, which also include all the accessories and the device for their operation as provided by the present invention.
From said fi~ures it can be seen that the pan~ls 1, illustrated diagrammatically, are joined together by way of the jointing elements 4, about which said~Panels 1 may rotate freely.
With the shutter completely extended, as shown in Figure 6, alter-nate jointing elements 4 are contained within the plane defined ~ ~ ~ 7~
by the straight lanes 16 of the upper and lower horizon-tal sections 15. Again with reference to Fiyure 6 with the shutter completely extended, the remaining jointing elements 4, i.e.
those which move out of and/or into said plane, are contained within a plane parallel -to and displaced from the preceding plane, defined substantially by a distance equal to one half the thickness of one of the panels 1. With particular reference to Figures 5 and 6, it can be seen that two normal end sectors 22, each provided with a flat ledge 23 one of which is complementary or conjugate to the other, are fitted to the two wlngs constituting the shutter by insertion.
The thickness of the flat ledges 23 is substan-tiallyone half the thickness of the panels 1 or of the end sectors 22.
The shanks 10 are inserted and fixed into the opposing ends of the jointing elements 4 designed to move out of the plane containing the shutter when completely extended, the outer ends of these shanks being provided with plates 12 which prevent the panels 1 from separating from -the jointing elements 4.
Shanks 10 provided with a plate 12 and a plate 14 are ~ , .
inserted into the ends of the jointing elements 4 designed to always remain within the plane defined by the shutter when completely extended, the plate 14 being housed in the straight channels 15' of the upper and lower sections 15 which individually support and guide the shutter during its opening and closing.
As an alternative to said plates 14, a "Teflon"
(trademark for polytetrafluoroethylene) wheel or a pair of opposlng TEFLON wheels may be mounted on the shanks 13 from which the plates 14 derive, these wheels running in the straight channels 15' of the upper and lower horizon-tal section 15.
This transforms the grazing friction of the plates 14 - into revolving friction of the TEFLON wheels to considerably reduce the force necessary for opening and closing the shutter.

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.~ ., " g ~e last two panels 1 of the two winqs constituting the shutter are provided both upperly and lowerly in proximity to the corresponding jointinq element 4, with a curved abutment 24 which during the closing and opening of the shutter comes into contact with, and rests against the vertical pegs 25 branching from the lower and upper sections 15, on which said pegs 25 are suitably positioned.
On the inner faces of said two last panels 1 of the two wings o~ the shutter there are fitted the two co~plementary parts of a normal locking device 26 for the two complementar~
wings. Two blocks 122 are provided on the centre line of that face of the horizontal sections 15 facing outwards from the shutter.
The upper face of the lower block 122 and the lower face of the upper block are at a slightly higher and slightly lower level respectively than the lower and upper corners of the shutter. On the sides of the shutter there are two vertical sections 27 which, in contrast to the horizontal sections 15, have a cross-section substantially of U configuration open toward the outer face of the shutter.
Said horizontal sections 15 are connected to the verti-cal sections 27 by three housings 28 and, at the lower right hand corner, by the housing 29 which is slightly wider than the hous-ings 28. Inside each housing 28 there is provided a pair of pivots 30 on which two grooved wheels 31 are idly mounted. Covers are fixed to the housings 28 by screwing screws into the pivots 30, and the cover 33 is fixed to the housing 29 in a similar manner.
Inside said housing 29 there are provided two grooved wheels 34 and a sprocket wheel 35 into which is inserted a prismatic shank deriving from a handle 36. ~ chain 37 is mounted over the three outer grooved wheels 31 and the sprocket wheel 35, its ends being connect~d to the tension spring 38 so that said chain 37 is constan-tly kept under tension.

Likewise, a seccnd chain 39 is mounted over the three inner grooved wheels 31, the pair of groovèd wh~els 34 and the sprocket wh~el 35, its ends being connected to the opposing ends of a tension spring 40 which keeps said chain 39 under constant tension. With particular reference to Figure 7, from the upper shank inserted into the jointinq element 4 to which the last panel 1 of the right hand wing is hinged, there derives an appendix 41 which is inserted into a link of the outer chain 37.
From the lower shank of the same element 4 there derives a second appendix, not shown ~or clarity of drawing, which is inserted into a link of the inner chain 39. The last jointing element 4 for the left hand wing of the shutter is connectéd to the two chains 37 and 39 in a different manner, namely upperly to the inner chain 39 and lowerly to the outer chain 37. Figures 11, 12 and 13 are diagrammatic frontal views of said chain device and two alternative designs, with the shutter or blind completely clos-ed.
In Figure 11 the heavy dashed and dotted line represents the centre line of the shutter, where the two last pannels 1 of the two wings forming the shutter come into contact. The heavy dashed and double dotted line represents the end edge of the shutter or blind constituted by a single wing. The said two heavy dashed and dotted and dashed and double dotted lines have the same meaning in Figures 12 and 13.
In Figure 11, the heavy dots indicate the points of connection of the last jointing element 4 of the right hand wing to the chains 37 and 39. The points indicated by a heavy x indi-cate the points of connection of the last jointing element 4 of the left hand wing to the ~aid inner chain 39 and outer chain 37.
The heavy square dots indicate the point of connection of the last jointing element 4 to said chains 37 and 39 in the case of a blind or shutter comprising a single wing. Said heavy dots, 1~.1'7~
heavv x points and heavy square roints, and the various reference numbers, have the same meaning in Figures 12 and 13.
In Fig. 12, the operating device differs from that des-cribed previGusly in that it comprises only one chain 20 which is wound and then turned backwards over the grooved wheels 31 and 34 to assume two substantially coxial C configurations which extend along three sides of the shutter frame, namely two horizon-tal sides and one vertical side. The tension spring 100 is connect-ed between the links of said chain 200 to keep -t~e chain under ten-1~ sion.
In figure 13, the second alternative design comprisestwo chains 70 and 80, the former wound endlessly along one hori-zontal side of the shutter frame and the latter wound endlessly along two sides, namely one vertical and the other horizontal.
The two springs 50 and 60 are connected between the links of said two chains 70 and 80 to keep said chains 70 and 80 under tension.
Whereas the chain 70 is driven by the sprocket wheel 35, the chain 80 is driven by the sprocket wheel 90 which is driven by said sprocket wheel 35 by way of a third chain 92 mounted on the two sprocket wheels 93 and 91, the former rigid and coaxial with the sprocket wheel 35 and the second rigid and coaxial with the sprocket wheel 90.
The third chain 92 is necessary to maintain the two loops formed by the chains 70 and 80 in the same plane. Should it not be necessary for these latter to lie in the same plane, the two chains 70 and 80 may be driven by a double sprocket wheel.
The operation of the blind provided with the operating device according to the present invention is as follows.
~ ssuming that the blind is completely closed, the opera-tor opens the locking device 16 locking the two wings of the shuttertogether, then rotates the sprocket wheel 35 clockwise by the handle 76 to drive the two chains 37 and 39, the first in a right 3Lt~}~
aanded and the second in a left handed direction.
By virtue of the two appendices 41 engaged upperly in the chain 37 and lowerly in the chain 39, the last jointing ele-ment 4 of the right hand wing is pulled toward the right, 50 caus-ing those jointing elements 9 not designed to remain within the vertical plane defined by the straight lanes 16 of the sections 15, to move outwards. The jointing elements 4 desi~ned to remain within the plane heretofore defined slide within said plane as the plates 14 are engaged in the straight channels 15'.
In an identical manner, the left hand wing simultaneously folds back and is pulled towards the left. During these opposing folding movements, any,additional friction and vibration of the shutter are easily absorbed and damped by the two traction springs 38 and 40. When the two wings have been almost completely folded back, the curved abutments 24 which branch from the last two panels l of said wings come into contact with the outer pegs 25 so that said last two panels 1 are rotated and rested against the two packs of panels l formed in proximity to the two vertical sec-tions 27. Said last two panels l then remain continuously-resting against the two formed packs because of the contact between said curved abutments 24 and said outer pegs 25.
To close the two wings of the shutter, the cycle of operations heretofore described is repeated in the reverse direc-tion. The inner pegs 25 are positioned in such a manner that on closure o the two wings, the curved abutments 24 come into con-tact with said inner pegs 25 to enable the rotation of the last - panel o~ the right hand wing to slightly lead the rotation of the last pannel l of the left hand wing. This enables the two end ~ectors 22 to rotate without interfering with the two blocks 122 and at th~ same time allows the two f lat ledges 23 to rest one against the other. The opening and closing of the blind or shutter comprising a single wing takes place in a manner enti~ely similar .L~ 7~
to that described for the double wing blind.
secause of the simplicity of the operating device, any description of operation of the two alternative designs illustrat-ed diagrammatically in Figures 12 and 13 is superfluous, both in the case of a double wing shutter and in the case of a single wing shutter, as the operation is substantially entirely similar to the operation heretofore described.
The position of the sprocket wheel 35 is not binding, and the sprocket wheel 35 may be positioned as required, in accor-dance with the method of operation, the environment in which the blind or shutter is located and whether this latter is of the double ~ing or single wing t~pe.
Finally, according to the invention, the operating handle 36 may be replaced by a convenient electric motor or any other equivalent means. Although the operating device according - to the invention is suitable for the type of blind or shutter described and illustrated in the two proposed designs, it may also be suitable for application to any other type of concertina-foldable blind.
The invention is not limited to the embodiments hereto-fore described and illustrated, which have been given simply by way of non-limiting example, bu~ also comprises all means which are the technical equivalent of the means described, and their combinations if these latter are conceived within the scope of the following claims.

Claims (21)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An improved mechanically operated concertina-foldable frame closure, which comprises:
- a frame including first and second parallel sections each having guide means;
- a plurality of elongated flat elements separated by elongated jointing elements, each flat element being hinged to its two adjacent jointing elements along respective and adjacent lateral edges;
- support means fixed to alternate jointing elements at both ends thereof and slidably engaged in said guide means of said first and second frame sections;
- at least one endless chain arranged inside said frame so as to define two coplanar chain portions in each of said first and second frame sections, each chain portion being guided at each corner of said frame by a respective idler wheel for movement of the chain portions in each frame section in opposite directions, at least one alternate jointing element being connected at one end thereof to one chain portion in said first frame section and, at the other end thereof, to another chain portion in said second frame section moving in the same direction as said one chain portion; and - a sprocket wheel located in one of said corners and engaging each endless chain so as to cause said one chain portion and said other chain portion to move in one direction or the opposite, thereby causing said alternate jointing elements to move towards or away from one another to respectively open or close said framed closure.

2. An improved framed closure as claimed in claim 1, wherein said jointing elements have a width substantially double the thickness of said flat elements.

3. An improved framed closure as claimed in claim 1, wherein the hinging axes of each flat element are in proximity to its two opposing faces and in a symmetrical position.

4. An improved framed closure as claimed in claim 1, wherein the hinging axes of each jointing element are in proximity to the same flat face.

5. An improved framed closure as claimed in claim 1, wherein the hinges between said flat elements and said jointing elements are constituted by a pair of conjugate projections of curled cross-section, and mutually copenetrating.

6. An improved framed closure as claimed in claim 1, wherein the hinges between said flat elements and said jointing elements comprises a double series of spaced-apart aligned sleeves joined by a single central pivot in the form of a rod.

7. An improved framed closure as claimed in claim 1, wherein the jointing elements comprises a hollow section adapted to receive at each end thereof a shank on which is mounted an end plate extending in width beyond the lateral edge of said section.

8. An improved framed closure as claimed in claim 6, wherein the pivot rods at each end of the jointing elements are locked onto an end plate.

9. An improved framed closure as claimed in claims 7 or 8, wherein said support means comprises a slide plate extending from alternate said end plates and adapted to slide in upper and lower guide portions of the frame.

10. An improved framed closure as claimed in claim 1, wherein the hinging axes of said alternate jointing elements are contained within the plane of said guide means.

11. An improved framed closure as claimed in claim 1, wherein the hinging axes of the jointing elements free of the guide means lie outside the plane of said guide means when the framed closure is extended.

12. An improved framed closure as claimed in claim 1, wherein a traction spring is disposed between the links of each endless chain to constantly keep said chain under tension and to damp any additional friction or vibration to which the framed closure is subjected during its opening or closure.

13. An improved framed closure as claimed in claim 1, wherein said sprocket wheel is provided with a square bore into which a prismatic shank of an operating handle is inserted.

14. An improved framed closure as claimed in claim 7, wherein the ends of the last jointing element are connected respectively to said one chain portion and said other chain portion by means of an appendix which extends from the shank at each end of said last jointing element and engages in the chain links.

15. An improved framed closure as claimed in claim 1, comprising a single endless chain mounted along two horizontal sides and one vertical side of the frame.

16. An improved framed closure as claimed in claim l, comprising two coplanar chains the first of which is endlessly mounted along one vertical side and one horizontal side of the frame, whereas the second is endlessly mounted at least along the other horizontal side of said frame, one of said chains being driven by said sprocket wheel, the second chain being driven by a second sprocket wheel driven by said drive sprocket wheel.

17. An improved framed closure as claimed in claim 1, comprising two coplanar endless chains mounted inside said frame, said chains being driven in opposite directions by said sprocket wheel.

18. An improved framed closure as claimed in claim 1, wherein the drive sprocket wheel is driven by an electric motor.

19. An improved framed closure as claimed in claim 1, wherein two pegs are provided on upper and lower horizontal sections of the frame, and against which there rest curved abutments deriving from the last flat element.

20. An improved frame closure as claimed in claim 1, wherein said elongated flat elements are panels, each panel having lateral edges with spirally curbed portions, and each jointing element has also two spirally extending edges, said spirally curved portions being axially inserted into said spirally extending edges.

21. An improved frame closure as claimed in claim 1, wherein each jointing element is provided with a longitudinal bore, a shank being secured inside each bore of each jointing element, a first plate being connected on top of each shank, a prismatic portion being connected to said first place, said prismatic portion terminating with a second plate parallel to said first plate.