WO2002048620A1

WO2002048620A1 - Grating for aeration ducts

Info

Publication number: WO2002048620A1
Application number: PCT/EP2001/014580
Authority: WO
Inventors: Nevio Savorani
Original assignee: San Marino Plast S.A.
Priority date: 2000-12-14
Filing date: 2001-12-12
Publication date: 2002-06-20
Also published as: ATE317963T1; DE60117224T2; DE60117224D1; EP1342037A1; EP1342037B1; ITBO20000726A0; ITBO20000726A1; ES2258058T3

Abstract

The grating according to the invention is formed with two or more pieces (1, 101), book articulated between them, so that they canbrought the one over the other with reciprocal approach of their internal front, so that the transversal overall dimensions of the grating can be reduced by half, and that the same grating can be inserted and can slide inside the aeration duct (C). At least one of the two pieces of the grating is provided in the internal front with grasping means (5) which are used to retain the same grating when it has come out from the duct, so that the two pieces of the same grating can be opened and disposed upon the same plane. The grasping means can be provided at least with one leaf spring (6) which anchors by bending and transversally inside of the aeration duct, to maintain the grating in the correct position on the outer front of said duct.

Description

TITLE: "Grating for aeration ducts" DESCRIPTION

The invention refers to the gratings, particularly of the type to be mounted on the aeration duct of the rooms in which operate combustion apparatus, for example,. for example boilers, stoves or the like and in which must be ensured a constant supply of atmospheric oxygen. Generally, the aeration ducts are obtained in the walls of the room and are closed on the two opposite faces by means of suitable gratings. The installation of the grating outside of the aeration duct, becomes problematic and it is sometime impossible when the room is placed at the upper floors of a building and is not externally provided with balconies or terraces.

The object of the invention is to realise a grating with reducible overall dimensions, which can be inserted from the inside of the room, in an aeration duct, until it comes out from said duct and in such a manner that, with few and simple manoeuvres the same grating can be restored in the flat condition and can be correctly and firmly assembled on the outer front of the same duct. Further purpose of the invention is to allow that said grating can be in any moment easily removed from the user for the periodical cleaning of the possible net which prevents the transit of the insects. Another purpose of the application is to allow that the same grating, if necessary, can be assembled also on the inner front of the aeration duct, like a very common grating of the known type.

These and other purpose are reached with a grating usually obtained by injection of plastics in a mould, formed by at least two pieces book-articulated between them, which can be lowered the one upon the other with reciprocally approach of their internal front, so that the transversal overall dimensions of the same grating can be substantially reduced by half and that the same grating can be inserted and caused to slide inside the aeration duct. At least one of the two pieces of the grating is provided in the internal front with fasteners which are used to retain the same grating when it has come out of the aeration duct, so that the two pieces of the same grating can be opened and disposed on the same plane, these fasteners being, if required, useful to fix the grating outside of the aeration duct. Further features of the invention, and the advantages deriving therefrom, will appear better evident from the following description of a preferred embodiment of same, made by way of non-limiting example, with reference to the figures of the attached sheets of drawings, in which: - Figure 1 is an elevation front view from the inside of the grating of the type which is referred to, provided with a rod with springs for setting in place;

Figure 2 shows the grating of Figure 1 sectioned along the line ll-il;

Figures 3, 3a, 4, 4a and 5, 5a show the grating in lateral elevation and during as many subsequent phases of the assembly upon the external end of a aeration duct;

Figure 6 is an elevation front view from the inside of an embodiment of the grating;

Figure 7 shows the grating of Figure 6 in lateral elevation, in the condition of reduced overall dimensions and during the phase of insertion inside the aeration duct;

Figure 8 is an elevation view from the inside of a grating according to a further embodiment;

Figure 9 shows the grating of Figure 8 in lateral elevation, in the condition of reduced overall dimensions and during the phase of insertion inside the aeration duct;

Figure 10 shows in lateral elevation the setting in place of a grating as shown in Figures 8 and 9, through a aeration duct having a small diameter and/or very long;

Figure 11 is an elevation view from the inside of an embodiment of the grating;

Figure 12 shows laterally and enlarged details pertinent to the hinges used in the grating of Figure 11 ;

Figure 13 is a lateral view and with parts in section of a grating according to the invention, with other fasteners in place;

Figure 14 is a frontal view of the fasteners of the grating of Figure 13;

Figure 15 shows in perspective a fitting for the grating of Figure 13, which allows the assembly of the same grating also on the inside of an aeration duct; Figure 16 shows in elevation from the inside, a copper or other material grating having reducible overall dimensions, according to the invention;

Figure 17 shows details of the grating of Figure 16 sectioned along the line XVII - XVII; - Figure 18 shows in elevation from inside an embodiment of the grating;

Figure 19 is a frontal view of the fasteners in place of the grating of Figure 18;

Figure 20 is a elevation view of the inside of a grating according to a further embodiment;

Figure 21 is an elevation view from the inside of a grating according to the invention, in the built-in version;

Figure 22 shows in perspective view details pertinent to the reciprocal articulation of the two pieces composing the grating of Figure 21 ;

Figure 23 shows in lateral elevation the possible removable realisation of the manipulating means of the grating of Figure 21 ; - Figure 24 shows the grating of Figure 21 sectioned transversally and fixed inside the aeration duct;

Figure 24a shows a simplified embodiment of the built-in grating;

Figure 25 shows in perspective view of an embodiment of the reciprocal articulation hinges of the two portions which usually compose the grating and of the articulation hinge to the same grating of the rod with the anchor spring;

Figure 26 shows frontally the rod with the anchor spring, partially sectioned in the articulation zone to the relative appendix of one of the two portions of the grating;

Figure 27 shows further details obtained according to the section line XXVII - XXVII of figure 26. With reference to Figures 1 and 2, it should be noted that the grating G according to the invention obtained in any known manner by means of injection of plastics into a mould, is fundamentally characterised by being composed of at least two pieces, 1 , 101 , joined, for example, upon a transversal axis, substantially median and mutually connected with one or more hinges 2 preferably placed inside of the same pieces and such that these pieces can be, if required, folded the one on the other like a book, so that the grating can assume an overall dimension in width H1 for example substantially halved with respect to its normal width H and so can be inserted through an aeration duct C (Figure 3) having a diameter inferior to said width H of the grating. It is clear how this condition increases as a consequence the range of the sections of the aeration conducts upon which it can be assembled a same grating of the type is referred.

It is understood that the pieces 1 , 101 which form the grating, can be formed, at their turn, by means one or more pieces in the case in which the grating must include a net R to prevent the transit of insects, which can be integral, fixed or removable for the periodical cleaning. The presence or not of the net R in the grating is a marginal and secondary argument of the same grating, extraneous to the understanding of the invention and therefore it is not here subsequently considered and examined closely, also because it is within the capacity of the common person skilled in the art. The hinges 2 can be formed, for example, by portions opportunely shaped, integrally obtained with the pieces which form the grating and pre-arranged in order to be reciprocally snap connected and in an articulated manner, or in order to be reciprocally articulated by means of pins, rivets or other suitable means. The hinges 2 can be, on the other hand, made of different material from the one that is composing the pieces 1 , 101 , and can be applied upon these, for example with solutions that will be considered further. The same hinges 2 can be finally placed in any suitable position of the grating, also different from the one that is shown in the drawings.

One of the pieces of the grating, for example the piece 1, carries for example in the central position an attachment 3 to which is articulated on an axis 4, for example orthogonal to the axis of the hinges 2, the end of a rod 5 of suitable length, integral with the end opposed to the center line of at least one leaf spring 6 externally convex and provided with sharp ends 106. The length Z of the spring 6 is opportunely superior to the diameter of the aeration duct C. According to known techniques, the grating can be commercialised with the rod 5 disconnected from the attachment 3, so that it can be superimposed with the minimum overall dimensions to the same grating, said rod 5 being predisposed for example for a snap coupling to the fulcrum axis 4. The connection of the rod 5 to the attachment 3 is such that the same rod can be turned against the grating as shown in Figure 1 and then can be rotated perpendicularly to the same grating. The thus conceived grating is installed in the following manner.

After the rod 5 has been brought the grating as shown in Figure 1 , the piece 101 is rotated upon the piece 1 of the same grating, as illustrated in Figure 2 with dotted line. With the pieces 1 , 101 of the grating downwardly oriented, as illustrated in Figure 3, with one hand is grasped the spring 6 and it is bent to reduce the length, in such a manner that the assembly of the grating in the condition of reduced overall dimensions can be inserted through the aeration duct C, as shown in Figure 3. The duct C usually has a length variable between 20 an 30 cm and usually has a diameter such that it can be easily passed through by the arm and the hand of the operator. When the hand with the grating comes out from the duct C, as shown in the Figure 3a, the operator leaves the spring 6 and grasp firmly the proximal portion of the rod 5 which protrudes, after which the said operator rotates the rod 5 of 180° around its own vertical axis, as shown in the sequence of the Figures 3a and 4, so that the two pieces 1 and 101 of the grating dispose themselves upon the same plane the one to the other, with the piece 1 which is directly connected to the rod, upwardly oriented. During the passage from the condition of Figure 3a to that of Figure 4, the pieces 1 and 101 of the grating touch reciprocally at the level of the articulation zone, to ensure structural and aesthetic continuity to the grating and the strict maintenance of the condition of co-planarity of the same pieces. In this phase, the fins A of the grating are already correctly downwardly oriented. As shown in Figure 4a, the operator then turns the grating downwardly of 90°, fulcrumed about the grasping point, so that for gravity the two pieces 1 and 101 of the same grating arrange themselves perpendicularly to the rod 5. Spring 6 is oriented with its own longitudinal axis lengthwise of duct C. In sequence of phase the operator rotates the grating upwardly of 90°, fulcrumed about the grasping point of the rod 5 in such a manner as to dispose said rod horizontally and the grating vertically, as shown in Figure 5. The two pieces of the grating remain in co-planar and position and perpendicular to the rod 5 and the pieces 1 remains upwardly oriented. The fins A of the grating are correctly downwardly oriented and the spring 6 is vertically disposed. At this point, the operator has to do nothing else than to withdraw the arm from the duct C, to introduce the spring 6 which flexes and that with its own sharp extremities 106 sliders on the same duct C, preventing the contrary movement of extraction of the grating. When the grating G comes against the external front of the wall upon which is opened the duct C, as shown in Figure 5a, the operator leaves the grasp of the rod 5 and takes off completely the hand form the duct C. So the grating remains, firmly installed.

In the Figures from 1 to 5a, with numeral reference 7 is indicated one string secured to a slot that, during the phase of installation of the grating remains secured with the other end for example to the other hand of the operator which effects the described assembling operation, in such a manner to allow the recover of the grating in case that this one accidentally escapes to the same operator.

It is evident how the described grating can be also used like a traditional grating and it can be assembled by pushing, also on the end of the duct C which is open inside the room to be ventilated.

In Figure 6 is shown an embodiment which provides the rod 5 formed by two pieces 105, 205, articulated between them upon an axis 9, for example orthogonal to that 4 of fulcrum of the same rod to the grating G, one of the said pieces being provided, for example, with a side ledge 10 for the other piece, in order to ensure the alignment of the same pieces during the phase of assembling of the grating. The articulation 9 allows to rotate the piece 205 in overlap to the piece 105 when this one is lowered upon the grating, like indicated with K1 in Figure 6. In this condition the spring 6 remains substantially comprised in the plan overall dimensions of the grating and the whole can be packaged with reduced overall dimensions. During the phase of installation of the grating, the articulation 9 allows to rotate the piece 205 perpendicularly to the piece 105 of the rod 5, as illustrated with K2 in Figure 6, so that the spring 6 results disposed parallel to the articulation axis of the hinges 2 of the grating. This condition allows the insertion of the grating in the aeration duct C, without the need of bending the spring 6, like in the previous case shown in Figure 1 , because the same hinge results now oriented according to the longitudinal axis of such duct, as appears from Figure 7.

This same condition can be obtained with the embodiment illustrated in Figure 8, according to which the fulcrum axis 4 of the rod 5 is oriented parallel to the axis of articulation of the hinges 2. When the rod 5 has been lowered upon the piece 1 and when the piece 101 has been lowered upon the piece 1 , the grating can be inserted in the aeration duct C without flexion of the spring 6, because it is oriented with is own major axis according the length of said duct, as clearly shown in Figure 9. When the grating of Figure 8 is installed, its fins A being parallel to the articulation axis of the hinges 2, the spring 6 results disposed horizontally and because of its weight the grating can go down and can partially uncover the aeration duct C. To avoid this drawback, the inferior piece 101 of the grating is provided in the internal front and in a median position of its own perimetrical edge, with one or more raised appendices 11 which can be inserted in the duct C in order to maintain the grating correctly disposed upon this latter. Figure 10 shows an embodiment of the grating which provides the head rod 5 provided with an appendix 12 to which it can be articulated in 13 an extension rod 14, useful to manoeuvre the grating during the insertion and assembling phases in the duct C, if said duct is with a diameter so reduced and/or with a length so elevated that it can not be passed through by the hand and/or the arm of one person. The rod 14 can be connected to the articulation 13 in such a manner that it can be traction- removed, the whole in a conceivable manner and easily realisable by persons skilled in the art.

The embodiment shown in Figure 11 , evidences out a grating G having the fins A perpendicular to the rotation axis of the hinges 2 so the same does not require the appendices 11 as in the solution of Figure 8, because in the phase of installation the spring 6 results to be disposed vertically. The pieces 1 and 101 of the grating are provided with diametrical ribs 15, 115 integral with the otherwise free ends of the fins. To the midline of the rib 15 is articulated in two points 4, 4' the fork or bow shaped foot of the rod 5. It is to be understood that with a similar bow configuration can be structured the foot of the rod 5 also in the other solutions shown in the drawings, for example also in the solution of Figure 8.

From the Figures 11 and 12 it is pointed out that the hinges 2, 2' can be constituted by means of articulated inserts, inserted or obtained with the technique of the bi-injection, realised for example in soft PVC, in polypropylene or in nylon. The inserts referred to are provided with two interconnected portions by means of a weakened zone, which acts like a hinge. The hinges of this type can be placed upon the frame of the grating, or in another suitable position.

The grating G shown in Figure 13, differs from the previous solutions because the piece 1 is provided in the midline of the side articulated to the other piece 101 , with an appendix 16 to which is anchored the end of a string 17 in its turn connected with the other end to the body 18 of an anchor (Fig. 14) the points of which are formed by three or four spring leafs 6 of the type already examined, placed to form an Y or an X. The grating G according to this variant, carries upon the inferior piece 101 the appendices 101 already considered with reference to Figure 8, suitable to bear upon the inferior edge of the external mouth of the duct C, to ensure the right disposition upon this one of the same grating which for gravity and for flexibility would tend to go down and partially uncover the duct C. According to an embodiment not shown, the string 17 can be assisted or replaced with a spring or the same can be made with elastic material, in order to ensure a correct permanence in the time of the grating G according to the solution referred.

Equipped with the grating as shown in Figures 13 and 14, can be provided a rod 19 as from figure 15, provided with ends 119 and 119' prearranged for the aligned coupling and with snap with the appendix 118 of the anchor 18 with the springs, whenever the same appendices 16 and 118 must be connected reciprocally no more in a flexible manner, by means of the string 17 above mentioned, but in a stiff manner, in order to allow the assembly of the grating upon the front which is directly accessible of a aeration duct, like a traditional grating.

Figure 16 shows a grating formed by two pieces 1 , 101 with fins and made of copper or other metallic material, the peripheral neck 20 of which is refolded like shown in Figure 17, to pinch the ends of frames 1', 101' of plastics, book-articulated between them with the hinges 2, one of the which is provided in central position to the grating, of the attachment 3 for the rod 5 or for other means of installation of the same grating, of the type described in the previous figures. According to an embodiment, not shown, the hinges may be made of flexible inserts crimped on the frame of the two pieces of the metallic grating and placed like a bridge between the same pieces, while the frames 1 ', 101' can be eliminated because an appendix for the anchorage of a string of the type shown in the solution of Figure 13, can be directly obtained in one of the two metallic pieces 1 or 101.

Figure 18 shows a type of grating G with the pieces 1 , 101 reciprocally articulated by means of hinges made of inserts of flexible plastic 2 as from Figures 11 , 12 and in which the support 5 of the installation springs has a portal configuration and is formed by two pieces 105, 205, articulated with one end in 4, 4', to appendices obtained integral with the fins of said pieces 1 , 101 , and provided on the other end with respective springs 6, 6' which realise in the whole a bow spring, said ends being predisposed with complementary snap coupling means, for example with respective concave and convex shapes 21 , 121 , which remain reciprocally connected when, with the grating assembled, the springs 6, 6' act against the internal wall of the aeration duct, but which allow in the initial phases of the assembly, to lower the pieces 105 and 205 in opposite directions upon the pieces 1 , 101 of the grating, to can rotate the same pieces of the grating in reciprocal approach and to insert the same grating in the aeration duct C.

Figure 20 shows a grating G formed with three pieces instead of two like in the previous hypothesis, with the central piece 201 which carries the attachment 3 for the installation fasteners of the grating and which carries couples of hinges 2, 2', for the articulation of the external pieces 1 , 101. Figure 21 shows a grating which unlike the gratings previously considered, is of the built-in version, provided with a peripheral neck which surrounds the fins A and which is pre-arranged for the friction engagement of the end of the aeration duct C: Also this grating can be divided into at least two pieces 1 , 101 , reciprocally articulated with hinges 2' which interest the edges of the annular neck for the containment of the fins, which can be placed projecting upon the internal side of said edges, like in the hypothesis of Figure 21 or can be obtained in a complementarily manner upon the same edges, like in the hypothesis of Figure 22: One of the pieces of the grating is provided in substantially central position with respect to the same grating and in the internal front, with an appendix 22 for example having a shape like a bushing, for example orthogonal to the fins A, in which there is snap and rotatably assembled the end bent at right angles of a rod 23, suitable to support the grating during the phase of installation like from Figure 24, said rod being destined to remain inside the aeration duct C and being provided with a double slope upon its own end 123, so that once the grating is installed, the same rod can be easily unthreaded from the bushing 22. It is to be understood that, in the field of the invention it is comprised also that constructive variation to the grating with reference to Figures 21 and 24, as shown in Figure 24a, according to which the bushing 22' is perpendicular to the fins A and is pre-arranged for the anchorage of a manipulation string 7 which can freely remain inside the aeration duct C.

With reference to Figures 25, 26 and 27, it is now described a particularly advantageous and functional realisation of the hinges 2 and of the articulation attachment of the rod 5, to one of the portions of the grating G. In a different way with respect to what is illustrated in the previous Figures, where the attachment 3 it has always been illustrated with a fork shape which was surrounding the foot of the rod 5, in the solution illustrated in the Figures referred to, the above mentioned terms are inverted. The attachment 3 is formed with a flat appendix integral for example with a transversal orientation to a near couple of fins A of the portion 1 of the grating and said appendix carries integral upon the opposite edges, pins aligned between them to form a single pin 4 and shaped with their free end having a flute spout shape, in such a manner to form inclined planes which converge toward the end of said appendix that is farther from the interior face of the grating. Said appendix 3 is for example inclined in such a manner that the axis of the pin 4 lies upon an ideal plane which is substantially perpendicular to the body of the grating and that intersects substantially the same in the median zone and/or of reciprocal contact of the portions

1 , 101 of the same grating (Fig. 27).

The foot of the rod 5 is structured with a fork shape 105, has the internal ends 24 opportunely flared and is provided with opposite bores 25, equal and aligned between them, having such a diameter which can rotatably house the pins 4 above mentioned, which snap enter in said bores when the fork 105 is pushed upon the appendix 3. The inclined planes of the pins 4 progressively divaricate the fork 105 until the same pins reach the bore 25 of the fork 105 and snap engage the same thanks to the elasticity of the material which forms the rod 5 which is such that the same fork comes back rapidly in the initial condition as from Figure 26. To avoid that appendix 3 undergoes undesired transversal bendings during the installation of the grating, on the edges of the fork foot 105 of the rod 5 are obtained integral and laterally projecting, bow runners 26 which co-operate with a ancillary rib 27 parallel to the pins 4 and connected to a near fin A of the grating, with small reinforcement and load distribution ties 28. Upon the internal sides of the fork 105, are provided projections 205 aligned between them and structurally disjointed in order not to limit the flexibility of the fins of said fork, which when the rod 5 is perpendicular to the grating, as shown in Figure 26 and 27, co-operate with the function of end abutment with a end tooth 103 of the appendix 3, stabilising the portions 5, 1 , 101 in the correct use position. It is to be understood that with the same principle describe for the rod 5, can be articulated to the grating referred to, the feet of others similar structures, bow-shaped which carry the anchorage spring 6, as shown for example in Figures 11 and 18.

With the same principle of articulation of the rod 5, can be realised the hinges

2, 2' of reciprocal articulation of the two portions of the grating 1 and 101. From Figure 25 it is noted that each hinge comprises a flat and bent appendix 102, parallel for example to said appendix 3 for the attachment of the rod 5 and integral to the near fins A and to said rib 27 of the portion 1 of the grating and which comprises a couple of flat and bent appendices 202 parallel between them and having a distance substantially equal to the thickness of said appendix 102 and integral with near fins A of the portion 101 of the grating, the appendix 102 being provided integrally with opposite pins 29 with the free end inclined like a flute spout, similar to the pins 4 above mentioned, while the couple of appendices 202 are provided with aligned bores 30 to house rotatably and with snap the said pins 29, when the same appendices 202 are forced upon those numbered 102. Because the hinges 2, 2' above mentioned, project from the internal face of the grating, as shown in Figure 27, the same hinges are placed in a such position so that they can engage the aeration duct C, when upon this one there is assembled the grating G referred to, as shown in Figure 5a.

I -?

Claims

1 ) Grating for the application on the outer front of aeration ducts, made usually of plastics, characterised by the fact that it is formed by at least two pieces (1 , 101 ) articulated between them in such a manner that they can be brought the one upon the other and to form a structure having a width at least substantially reduced by half with respect to the overall width of the same pieces, so that said reduced dimensions structure can be inserted from the inside in an aeration duct (C), crosses completely the same and comes out on the outside, means being provided to easily carry back and to firmly maintain the same pieces of the grating in the reciprocally co-planar position, to rearrange the same grating and to dispose it perpendicularly to the duct, means provided to easily and safely support the grating during the phases of insertion above mentioned and in the following phases and means being provided for the anchorage to the duct to firmly maintain installed in place said grating.

2) Grating according to claim 1 ), in which the pieces (1 , 101) which compose the same grating are articulated by means one or more hinges of any suitable kind (2, 2') placed preferably upon the inner front of said pieces so that they can rotate in reciprocal approach with this front, there being provided that, when the same are disposed on the same plane, the same pieces enter in reciprocal contact to ensure structural and aestethic continuity to the grating and to remain between them on the same plane when the said grating is installed.

3) Grating according to claim 1), of the type having a completely external collocation to the aeration duct, characterised by the fact that one of the pieces which constitutes the same grating carries articulated in a substantially central zone of the same grating, a rod (5) having a suitable length, which can be lowered upon the grating to allow the reduction of the overall dimensions during the installation and which it can then be carried perpendicularly to the same grating after having traversed of the aeration duct, the said rod being provided on the other end with at least a bow spring (6) having its ends pointed (106), suitable to be disposed with correct bending and transversally inside the aeration duct, to be firmly anchored to this one and to correctly and firmly retain the grating upon the front of said duct (C). 4) Grating according to claim 3), in which the rod (5) with the anchorage spring (6) is articulated to one piece (1 ) of the same grating, with the possibility to oscillate upon an axis (4) orthogonal to the axis of the articulation hinges (2, 2') for the articulation of the pieces which compose the same grating. 5) Grating according to claim 4), in which the rod (5) with the anchorage spring (6) is formed by two pieces (105, 205) articulated between them upon an axis (9) orthogonal to the one (4) for the articulation of the same rod to the grating, in such a manner that lowering the main piece (105) upon the grating and disposing the other piece perpendicular to the first one, the anchor springs result oriented according the longitudinal axis of the aeration duct when inside this one is inserted the grating in the condition of reduced overall dimensions.

6) Grating according to claim 3) in which the rod (5) with the anchorage spring (6) is articulated to one piece (1 ) of the sale grating with the possibility to oscillate upon an axis (4) parallel to the one of the hinges (2, 2') for the articulation of the pieces (1 , 101) which compose the same grating, so that said spring results oriented according to the longitudinal axis of the duct when inside this one is inserted the grating in the condition of reduced overall dimensions.

7) Grating according to claim 6) characterised by the fact that if its fins (A) are parallel to the axis of the articulation hinges of the pieces (2, 2') which compose the same grating, the piece of the grating that during the installation remains in the low position, is provided inside and in correspondence of the perimetrical edge, with projecting appendices (11 ) which bear upon the inferior portion of the edge of -the aeration duct, to maintain the same grating correctly and firmly positioned in front of said duct. 8) Grating according to claim 6), characterised by the fact that it has the fins (A) orthogonal to the axis of the hinges (2, 2') for the articulation of the pieces (1 , 101 ) which compose the same grating.

9) Grating according to the preceding claims, characterised by the fact that the rod (5) which supports the anchorage spring (6) for the installation of the same grating, is symmetrically articulated in two points (4, 4') to one piece (1) of the said grating, and is substantially portal shaped.

10) Grating according to claim 9) in which the rod (5) having a shape like a portal is divided into two pieces (105, 205) that by their foot are articulated to the respective pieces (1 , 101 ) which compose the grating, with the articulation axis (4, 4') orthogonal to the axis of the hinges (2, 2') for the articulation of the same pieces to the grating, the other ends of said two pieces of the rod, being predisposed for a snap-coupling (21 , 121 ) and being provided with respective portions of leaf-springs (6, 6'), so that they can be disconnected and lowered upon the respective piece of grating when this latter must be reduced in its dimensions for the assembling in the aeration duct.

_.11) Grating according to claim 3), characterised by the fact that it is formed with three pieces, with the central piece (201 ) which carries articulated on the opposite sides the other two pieces (1 , 101 ) and which carries the anchorage spring means to be fixed inside the aeration duct. 12) Grating according to claim 3), characterised by the fact that the end of the rod (5) which carries the anchorage spring (6) can be predisposed for the articulated connection (12, 13) to the end of a rod (14) suitable like extension in the case in which the hand and/or the arm of the operator are prevented from the crossing the aeration duct (C) for the installation of the same grating. 13) Grating according to claim 2) in which the hinge or the hinges (2, 2') of reciprocal connection of the pieces which compose the same grating, are constituted by portions integrally obtained with the two pieces which compose the same grating and reciprocally snap-coupled or with other technique which allows the reciprocal rotation of the portion of the hinge. 14) Grating according to claim 2), in which the reciprocal articulation hinges (2, 2') of the pieces which compose the same grating, are realised in any other material different from the one of the grating and are obtained and fixed on the inside of the pieces which compose the same grating. 15) Grating according the claim 1 ) in which the reciprocal articulation hinges (2, 2') of the pieces which compose the same grating, are realised with soft plastics, are provided with a bending weak zone and such hinges are applied upon the grating or are obtained integral with this one, with the injection technique or multi-injection technique of different materials.

16) Grating according to claim 3), characterised by the fact that instead of the rod (5) with the anchorage springs (6), one of the pieces which compose the same grating is provided in a substantially central position to the same grating, with an appendix (16) to which is anchored a string (17) that with the other end is connected to the body (18) of an anchor having three or more points formed by leaf springs (6) for the anchorage inside the aeration duct. 17) Grating according to claim 16, in which the appendices (16, .118) fixing the string (17) to the grating and to the body (18) of the anchor with the springs (6), are predisposed to be snap connected, rather than with said string, to a rod (19) which allows the assembling of the grating upon the front directly accessible of the aeration duct, like a conventional grating. 18) Grating according to claim 3), characterised by the fact that it is realised in copper or any other metallic material and by the fact that the two or more pieces which compose the same, are fixed by means of bending of their perimetrical edges (20) upon hinges or upon the periphery of frames (1 , 101') made of plastics, book- articulated between them and provided with means for the anchorage to the internal surface of the aeration duct, like in the previous gratings

19) Grating according to claim 3), characterised by the fact that it provided with a string (7) to be anchored to the opportunely predisposed end of the rod with the anchorage springs (6), suitable for the manipulation and/or for the recover of the grating in the case this one escapes from the hand of the operator which is installing the same into the duct.

20) Grating according to claim 1 ) particularly if intended to be built-in upon the end of a aeration duct (C) characterised by the fact that the articulation hinges (2, 2') of the pieces which compose the same grating are arranged to connect of the neck of the grating which is inserted with pressure in said duct, the grating being provided for the installation with an articulated rod (23) or with a string (7) anchored in permanent or removable manner to a bush or to other appendix (22, 22') integral to the inside of one of the pieces which compose said grating.

21 ) Grating according to claim 2), in which the reciprocal articulation hinges (2, 2') of the two portions (1 , 101 ) which compose the same grating (G) comprise in correspondence of the conjunction side of the two said portions, inclined and flat appendices (102) integral to one side (1) of the grating and provided integral upon the end, with lateral and opposite pins, aligned between them, having the free end shaped like a flute spout, while on the other portion (101) of the grating are provided couple of flat and inclined appendices parallel between them (202) having a distance between them substantially equal to the thickness of said appendices (102) and provided with aligned bores (30) in which can be snap inserted the pins (29) of this said appendices (102) when in the same are forced the internally flared ends of said couple of parallel appendices (202).

22) Grating according to claim 21) in which the inclined planes formed from the flute spout ends of the pins (4) of the flat appendices (102) of the hinges (2, 2') converge towards the free end of said appendices (102).

23) Grating according to claim 21), in which the appendices (102, 202) of the articulation hinges (2, 2') of the two portions (1 , 101 ) which compose the grating (G), being projecting from the inside of the same grating, are integral to pairs of nearby fins (A) of said portions of the grating and are placed in intermediate zones and such to engage the aeration duct (C) upon the end of which is assembled the same grating.

24) Grating according to claim 9), in which the foot of the rod (5) with the anchorage spring (6) or the feet of the equivalent bow or portal structure, are characterised by a fork shape (105) with an internal flaring (24) on the end and are provided laterally with aligned and opposite bores (25) in which can be snap inserted opposite and aligned flute spout shaped pins (4) with the free end and integral laterally to flat and inclined appendices (3), at their turn integral to nearby fins (A) of the corresponding portion of the grating. 25) Grating according to claim 24), in which the foot of the fork (105) of the rod (5) or of the corresponding bow structure with the anchorage spring (6) for the installation of the grating (G), is characterise by a bow shape and by the fact that the same presents lateral and projecting bow runners (26) which co-operate with a rib (27) parallel to the fins (A) of the same grating and which is connected to this one, also with reinforcement ties (28, 102).

26) Grating according to claim 24), in which on the internal face of the two wings of said fork foot (105), are provided projections (205) which co-operate with the function of end of stroke with an end tooth (103) of the flat appendix (3) to which is articulated the same fork foot (105) when the rod (5) with the anchorage spring (6) is oriented perpendicularly to the portion of the grating (1 ) to which is restrained.