A screening apparatus for screening an opening

Abstract

A screening apparatus (1), comprising a flexible guide unit (7) and a sliding bar (11): which is fixable to an edge of a screen cloth (5); which comprises a first (12) and a second end portion (13), opposite one another; which comprises a first guide channel (16) of a variable part of the first guide unit decoupled from the cloth; in which the first guide channel (16) comprises: a first guide portion (25) which is curved, which originates from the first end portion; a second guide portion (26) which is straight, which originates from the first guide portion, which extends towards the second end portion (13); a third guide portion (27), which is curved, which originates from the second guide portion (26), which is arranged in the second end portion; a fourth guide portion (28), which is straight, which originates from the third guide portion (27), and which extends towards the first end portion (12); for slidably receiving and flexing the variable part of the first guide unit (7) during a first activation of the sliding bar (11) for reducing the screening to a minimum, forming the following sections of the guide unit: a first section (14), at least partially curved, in the first guide portion; a second straight section (15), in the second guide portion; a third curved section (72), in the third guide portion; and a fourth straight section (73) in the fourth guide portion.

Description

[0001] A SCREENING APPARATUS FOR SCREENING AN OPENING

[0002] DESCRIPTION OF THE INVENTION

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to the technical sector of a screening apparatus of an opening, preferably made in a wall. The screening apparatus is of a horizontally sliding type and comprises a screen cloth that is rollable about a vertical axis.

[0005] DESCRIPTION OF THE PRIOR ART

[0006] With reference to the figures of the prior art 1 , 2, 8 and 9, a screening apparatus (100) is known for screening an opening, which opening is rectangular and comprises a first side (3) which is vertical. This screening apparatus has the following characteristics:

[0007] - it comprises a frame;

[0008] - it comprises a housing (102) which is part of the frame and which is vertically positionable at the first side (3) of the opening;

[0009] - it comprises a winding roller (not illustrated in figures 1-9, relative to the prior art) which is housable vertically in the first housing (102) so as to rotate with respect to the axis thereof;

[0010] - it comprises a screen cloth (105) which comprises: a first edge which is fixed to the winding roller so that the screen cloth (5) can be wound on, and be unwound from, the winding roller; a second edge opposite the first edge; a third edge (106) which is interposed between the first edge and the second edge; and a fourth edge (108) which is opposite the third edge (106);

[0011] - it comprises a first guide unit (107) for inferiorly guiding the screen cloth (105); which is couplable to the third edge (106) of the screen cloth (105); which extends in a longitudinal direction; comprises a first end (138), which is fixable: to the frame in proximity of the lower part of the first side (3) of the opening or at the lower part of the first side (3) of the opening; which comprises a second end (139) opposite the first end (138); and can flex along the extension thereof so as to form: at least a straight section and at least a curved section;

[0012] - it comprises a sliding bar (111) which: is fixable to the second edge of the screen cloth (105); comprises a first end portion (112) and a second end portion (113), which is opposite the first end portion (112); which comprises a first guide channel (116) for guiding at least a variable part of the first guide unit (107) which is decoupled from the third edge (106) of the cloth.

[0013] The first guide channel (116) originates at the first end portion (112) of the sliding bar (111), extends in the sliding bar (111) and comprises: a first guide portion

[0014] (125) (see figures 1 and 9), which originates at the first end portion (112) of the sliding bar (111) and which is at least partially curved; a second guide portion

[0015] (126) which originates from the first guide portion (125) of the first guide channel (116), which is straight and which extends towards the second end portion (113) of the sliding bar (111).

[0016] During a first activation of the sliding bar (111) along a screening plane (121) and aimed at reducing the screening of the opening to a minimum (see figure 8, in which the screening apparatus (100) is in the minimum screening configuration), there progressively form: a first section (114) of the first guide unit (107), which is at least partially curved, in the first guide portion (125) of the first guide channel (116); a second section (115) of the first guide unit (107), which is straight, in the second guide portion (126) of the first guide channel (116).

[0017] Some known screening apparatuses (100) (see figures 3-7) can further comprise a compensating unit (110) which extends in a longitudinal direction; which comprises a first end portion (140) and a second and opposite end portion (141) (see figures 3 and 6). The first end (140) is fixable: to the frame in proximity of the upper part of the first side (3) of the opening; or at the upper part of the first side (3) of the opening. The compensating unit (110) can flex along the extension thereof to form at least a straight section and at least a curved section.

[0018] In this case, the sliding bar (111) further comprises a second guide channel (117) for guiding at least a variable part of the compensating unit (110). The second guide channel (117) originates at the second end portion (113) of the sliding bar (111) and extends in the sliding bar (111). This is in order, at least partially, to slidably receive and flex the variable part of the compensating unit (110). During the first activation of the sliding bar (111), there is a progressive forming of a first section (174) of the first guide unit (110) which is at least partially curved and a second section (175) of the compensating unit (110), which originates from the first section of the compensating unit (110), which is straight and which comprises the second end (141) of the compensating unit (110). Further, the known screening apparatuses (100) generally also comprise a synchronising unit for synchronising the sliding of the variable part of the first guide unit (107) in the first guide channel (116) and of the variable part of the compensating unit (110) in the second guide channel (117). The synchronising unit is connectable to the first guide unit (107) and to the compensating unit (110). The compensating unit (110) and the synchronising unit are configured in such a way as, in use, to maintain the sliding bar (111) vertically orientated during any activation of the sliding bar (111), along the screening plane (121) and aimed at increasing or reducing the screening of the opening along the screening plane (121).

[0019] As shown in figures 3 and 6, the synchronising unit can comprise two synchronising cables (200) and two direction inverting elements (119). The compensating unit (110) can be a second compensating chain (110) (see for example figures 3-5), which is flexible and which comprises a plurality of second chain elements, or, alternatively, can be a flexible metal strap (110) (see figures 6- 7).

[0020] In any case, as can be observed by the comparison of figures 8 and 9, the known screening apparatuses (100), in a maximum screening configuration, can have a maximum screening portion of the screen cloth (105) having a horizontal extension (190) that cannot be greater than the length (191) of the second guide portion (126) of the first guide channel (116). Therefore the maximum screening portion of the screen cloth (105), in the maximum screening configuration, is limited by the length (191) of the second guide portion (126) of the first guide channel (116) which is, in substance, correlated to the length of the sliding bar (111).

[0021] This, in practice, means that it is not possible to screen, with a single screening apparatus of known type, an opening that has a horizontal side that is equal to or larger than the vertical side. Further, when the compensating unit (110) is present, in the maximum screening configuration, the fourth edge (108) of the screen cloth (105) can move from the screening plane (121), for example, if it is windy, as it is not adequately guided. For the same reason, at the fourth edge (108) of the screen cloth (105), insects can pass through.

[0022] In this matter, note the pair of brushes (147) visible in figures 4 and 7, which is fixed to a second housing (142). This is arranged on a second horizontal side of the opening. The pair of brushes (147) has longer bristles than a traditional guide unit with brushes. The latter is known in the technical sector as a “windproof guide unit” and has short and stiff brushes to adequately guide the fourth edge (108) of the screen cloth.

[0023] Further, as it is necessary to enable the second end portion (113) of the sliding bar (111) to slide between the pair of brushes (147) during the relative activation, the bristles of the pair of brushes (147) cannot be rigid, otherwise they would obstruct the activation. Consequently, the long and soft bristles of the pair of brushes (147) do not ensure a suitable guide of the fourth edge (108) of the screen cloth (105) as they have a guide efficiency that is evidently of modest entity. For this reason, insects can cross the opening, at the fourth edge (108) of the screen cloth (105), when the known screening apparatus (100) has a compensating unit (110) as illustrated in figures 3-6.

[0024] In practice, in the screening apparatuses (100) of the prior art, it is not possible to have both a compensating unit (110) (which compensates the first guide unit (107), following the activation of the sliding bar), and a second guide unit that is effective for guiding the fourth edge (108) of the screen cloth (105).

[0025] It would be advantageous to have a screening apparatus that compensates the activation of the sliding bar and, contemporaneously, also ensures a suitable guide to the fourth edge of the screen cloth, while preventing the fourth edge from displacing from the screening plane and preventing passage of insects in proximity of the fourth edge.

[0026] SUMMARY OF THE INVENTION

[0027] The aim of the present invention therefore consists in obviating the drawbacks of the known screening apparatuses.

[0028] In particular, the main aim of the invention is to entirely screen, with a single screening apparatus, also the openings having a horizontal side, equal or larger than the vertical side and, at most, nearly twice the vertical side.

[0029] A further aim consists in obtaining, in the maximum screening configuration and, given an equal height of the sliding bar, a greater maximum screening portion of the screen cloth.

[0030] An aim of the present invention consists in providing a screening apparatus which at the same time enables compensating the first guide unit following the activating of the sliding bar, and effectively guiding the fourth edge of the screen cloth to prevent it moving out of the screening plane and also preventing passage of insects in proximity of the fourth edge.

[0031] The above aims are attained by a screening apparatus for screening an opening made in a wall, according to claim 1 .

[0032] As can be observed by a comparison of figures 8-9 (relative to the prior art) and 10-13 and 98 (relative to the invention), according to the invention, the horizontal dimension of the maximum screening portion of the screen cloth (5), in the maximum screening configuration, has a horizontal extension (400), which is equal to the distance that the sliding bar can shift (also called the “stroke” of the sliding bar). The horizontal extension (400) is considerable greater than the length (401) of the second guide portion (26) of the first guide channel (16). In fact, the horizontal extension (400) is given by the sum of the lengths (401) of the second guide portion (26) of the first guide channel (16), of the length (403) of the third guide portion (27) of the first guide channel (16) and of the length (402) of the fourth guide portion (28) of the first guide channel (16). This advantageously enables using a single screening apparatus for also screening openings having a horizontal side, equal or larger than the vertical side and, at most, nearly twice the vertical side.

[0033] It is obvious that, according to the invention, in the maximum screening configuration, and, given an equal height of the sliding bar, the screening apparatus of the invention has a greater maximum screening portion of the screen cloth.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In the following part of the present description, specific forms of actuation and embodiments of the invention will be described, according to what is set down in the claims and with the aid of the accompanying tables of drawings, in which figures 1-9 relate to the prior art and the remaining figures relate to the invention, in which:

[0036] - figure 1 is a schematic frontal view first known screening apparatus;

[0037] - figure 2 is a schematic view in section of the first known screening apparatus of figure 1 along section plane A-A of figure 1 ;

[0038] - figure 3 is a schematic frontal view of a second known screening apparatus;

[0039] - figure 4 is a schematic view in section of the second known screening apparatus of figure 3 along section plane A-A of figure 3;

[0040] - figure 5 is a partial schematic view in section of the second known screening apparatus of figure 3 along section plane B-B of figure 3;

[0041] - figure 6 is a schematic frontal view of a third known screening apparatus;

[0042] - figure 7 is a schematic view in section of the third known screening apparatus of figure 6 along section plane A-A of figure 6;

[0043] - figure 8 is a schematic frontal view of the first known screening apparatus of figure 1 in a minimum screening configuration of the opening;

[0044] - figure 9 is a schematic frontal view of the first known screening apparatus of figure 1 in a maximum screening configuration of the opening;

[0045] - figure 10 is a schematic frontal view of a first embodiment of the screening apparatus of the invention in an intermediate screening configuration;

[0046] - figure 11 is a schematic view in section along section plane A-A of figure 10;

[0047] - figure 12 is a schematic frontal view of the screening apparatus of figure 10 in a minimum screening configuration; - figure 13 is a schematic frontal view of the screening apparatus of figure 10 in a maximum screening configuration;

[0048] - figure 14 is a schematic perspective view of the screening apparatus of figure 10 in a minimum screening configuration;

[0049] - figure 15 is a schematic perspective view of the screening apparatus of figure 10 in an intermediate screening configuration;

[0050] - figure 16 is a schematic perspective view of the screening apparatus of figure 10 in a maximum screening configuration;

[0051] - figure 17 is a schematic frontal view according to a second embodiment of the screening apparatus of the invention in an intermediate screening configuration of the opening;

[0052] - figure 18 is a section view along section plane A-A of figure 17;

[0053] - figure 19 is a schematic frontal view of the screening apparatus of figure 17 in a minimum screening configuration of the opening;

[0054] - figure 20 is a schematic frontal view of the screening apparatus of figure 17 in a maximum screening configuration of the opening;

[0055] - figure 21 is a schematic frontal view of a third embodiment of the screening apparatus of the invention in an intermediate screening configuration of the opening;

[0056] - figure 22 is a section view along section plane A-A of figure 21

[0057] - figure 23 is a schematic frontal view of the screening apparatus of figure 21 in a minimum screening configuration of the opening;

[0058] - figure 24 is a schematic frontal view of the screening apparatus of figure 21 in a maximum screening configuration of the opening;

[0059] - figure 25 is a schematic perspective view of a fourth embodiment of the screening apparatus of the invention in a minimum screening configuration of the opening;

[0060] - figure 26 is a schematic perspective view of the screening apparatus of figure 25 according to the invention in an intermediate screening configuration of the opening;

[0061] - figure 27 is a schematic perspective view of the screening apparatus of figure 25 according to the invention in a maximum screening configuration of the opening;

[0062] - figure 28 is a schematic frontal view of the screening apparatus of figure 25 in the intermediate screening configuration;

[0063] - figure 29 is a partial schematic view in section of the screening apparatus of figure 28 along section plane A-A of figure 28;

[0064] - figure 30 is a partial schematic view in section of the screening apparatus of figure 28 along section plane A-A of figure 28;

[0065] - figure 31 is a section view of the screening apparatus of figure 28 along section plane C-C of figure 28;

[0066] - figure 32 is a section view of the screening apparatus of figure 28 along section plane D-D of figure 28;

[0067] - figure 33 is a partial view in transversal section of a fifth embodiment of the screening apparatus of the invention;

[0068] - figure 34 is a perspective view from a first side of a component of the screening apparatus of figure 33;

[0069] - figure 35 is a perspective view from a second side of the component of figure 34;

[0070] - figure 36 is a partial view in transversal section of a sixth embodiment of the screening apparatus of the invention;

[0071] - figure 37 is a perspective view from a first side of a component of the screening apparatus of figure 36;

[0072] - figure 38 is a perspective view from a first side of a further component of the screening apparatus of figure 36;

[0073] - figure 39 is a perspective view from a second side of the further component of figure 38; - figure 40 is a partial view in transversal section of a seventh embodiment of the screening apparatus of the invention;

[0074] - figure 41 is a perspective view from a first side of a component of the screening apparatus of figure 40;

[0075] - figure 42 is a perspective view from a first side of a further component of the screening apparatus of figure 40;

[0076] - figure 43 is a perspective view from a second side of the further component of figure 42;

[0077] - figure 44 is a schematic view from above of an eighth embodiment of the screening apparatus of the invention in an intermediate screening configuration of the opening;

[0078] - figure 45 is a schematic frontal view in section along plane A-A of the screening apparatus of figure 44 in the same configuration;

[0079] - figure 46 is a schematic frontal view in section along plane B-B of the screening apparatus of figure 44 in the same configuration;

[0080] - figure 47 is a schematic frontal view of a ninth embodiment of the screening apparatus of the invention in a minimum screening configuration of the opening;

[0081] - figure 48 is a diagram illustrating a group of components of the screening apparatus of figure 47 in the same configuration;

[0082] - figure 49 is a diagram illustrating a group of components of the screening apparatus of figure 47 in the same configuration;

[0083] - figure 50 is a schematic frontal view of the screening apparatus of figure 47 in an intermediate screening configuration of the opening;

[0084] - figure 51 is a diagram which illustrates the group of components of figure 48 in an intermediate screening configuration of the opening; figure 52 is a diagram which illustrates the group of components of figure 49 in an intermediate screening configuration of the opening;

[0085] - figure 53 is a schematic frontal view of the screening apparatus of figure 47 in a maximum screening configuration of the opening;

[0086] - figure 54 is a diagram which illustrates the group of components of figure 48 in a maximum screening configuration of the opening;

[0087] - figure 55 is a diagram which illustrates the group of components of figure 49 in a maximum screening configuration of the opening;

[0088] - figure 56 is a schematic frontal view of a tenth embodiment of the screening apparatus of the invention in an intermediate screening configuration of the opening;

[0089] - figure 57 is a diagram illustrating a group of components of the screening apparatus of figure 56 in the same configuration;

[0090] - figure 58 is a diagram illustrating a group of components of the screening apparatus of figure 56 in the same configuration;

[0091] - figure 59 is a partial view of the screening apparatus of figure 56 along section plane A-A of figure 56;

[0092] - figure 60 is a partial view in section of the screening apparatus of figure 56 along section plane B-B of figure 56;

[0093] - figure 61 is a schematic frontal view of the screening apparatus of figure 56 in a minimum screening configuration of the opening;

[0094] - figure 62 is a diagram which illustrates the group of components of figure 57 in a minimum screening configuration of the opening; figure 63 is a diagram which illustrates the group of components of figure 58 in a minimum screening configuration of the opening;

[0095] - figure 64 is a partial view in section of the screening apparatus of figure 61 along section plane A-A of figure 61 ;

[0096] - figure 65 is a partial view in section of the screening apparatus of figure 61 along section plane B-B of figure 61 ;

[0097] - figure 66 is a schematic frontal view of the screening apparatus of figure 56 in a maximum screening configuration of the opening; - figure 67 is a diagram which illustrates the group of components of figure 57 in a maximum screening configuration of the opening;

[0098] - figure 68 is a diagram which illustrates the group of components of figure 58 in a maximum screening configuration of the opening;

[0099] - figure 69 is a partial view of the screening apparatus of figure 66 along section plane A-A of figure 66;

[0100] - figure 70 is a partial view in section of the screening apparatus of figure 66 along section plane B-B of figure 66;

[0101] - figure 71 is a schematic view from above of the screening apparatus of figure 56 in the minimum screening configuration of the opening;

[0102] - figure 72 is a schematic view in section of the screening apparatus of figure 71 along section plane A-A of figure 71 , in which the positioning of the group of components of figure 57 is evidenced;

[0103] - figure 73 is a schematic view from above of the screening apparatus of figure 56 in the minimum screening configuration of the opening;

[0104] - figure 74 is a schematic view in section of the screening apparatus of figure 73 along section plane A-A of figure 7 in which the positioning of the group of components of figure 58 is highlighted;

[0105] - figure 75 is a perspective view of an eleventh embodiment of the screening apparatus of the invention in an intermediate screening configuration of the opening;

[0106] - figure 76 is a larger-scale schematic view in transversal section of a component illustrated in figure 75:

[0107] - figure 77 is a schematic frontal view of the screening apparatus of figure 75, in the same configuration;

[0108] - figure 78 is a partial view in transversal section of a twelfth embodiment of the screening apparatus of the invention;

[0109] - figure 79 is a partial view in transversal section of a thirteenth embodiment of the screening apparatus of the invention;

[0110] - figure 80 is a partial view in transversal section of a fourteenth embodiment of the screening apparatus of the invention;

[0111] - figures 81 , 82, 83 are perspective views, from different angles, of a novel compensating chain element utilisable in the invention;

[0112] - figure 84 is a perspective view of a novel compensating chain element utilisable in the invention;

[0113] - figure 85 is a frontal view of the novel compensating chain element of figure 82;

[0114] - figure 86 is a partial view in transversal section of a fifteenth embodiment of the screening apparatus of the invention;

[0115] - figures 87, 88, 89 are perspective views of a novel compensating chain element utilisable in the invention, taken from different angles;

[0116] - figure 90 is a perspective view of a novel guide chain in a first configuration;

[0117] - figure 91 is a perspective view of the novel guide chain of figure 90 in a second configuration;

[0118] - figure 92 is a schematic rear view, with some parts sectioned of a sixteenth embodiment of the screening apparatus of the invention in a maximum screening configuration;

[0119] - figure 93 is a schematic view in transversal section, along section plane A-A of figure 92, of the screening apparatus of figure 92 in a maximum screening configuration;

[0120] - figure 94 is a schematic frontal view, with some parts sectioned, of the screening apparatus of figure 92 in a maximum screening configuration;

[0121] - figure 95 is a schematic rear view, with some parts removed, of the screening apparatus of figure 92 in a minimum screening configuration of the opening;

[0122] - figure 96 is a schematic frontal view, with some parts removed, of the screening apparatus in a minimum screening configuration; - figure 97 is a schematic frontal view, with some parts sectioned, of some of the components of the screening apparatus of figure 45;

[0123] - figure 98 is a schematic frontal view, with some parts sectioned, of some of the components of the screening apparatus of figure 46;

[0124] - figure 99 is a schematic frontal view of a seventeenth embodiment of the screening apparatus of the invention;

[0125] - figure 100 is a schematic view, partial and sectioned, of the screening apparatus of figure 99 along section plane B-B of figure 99;

[0126] - figure 101 is a schematic view, partial and sectioned, of the screening apparatus of figure 99 along section plane A-A of figure 99;

[0127] - figure 102 is a schematic view, partial and sectioned, of the screening apparatus of figure 99 along section plane C-C of figure 99;

[0128] - figure 103 is a schematic frontal view of an eighteenth embodiment of the screening apparatus of the invention in a maximum screening configuration of the opening;

[0129] - figure 104 is a diagram illustrating a group of components of the screening apparatus of figure 103 viewed laterally and in the maximum screening configuration;

[0130] - figure 105 is a diagram illustrating a group of components of the screening apparatus of figure 103 viewed frontally and in the maximum screening configuration;

[0131] - figure 106 is a diagram illustrating a further group of components of the screening apparatus of figure 103, viewed laterally and in the maximum screening configuration;

[0132] - figure 107 is a diagram illustrating a further group of components of the screening apparatus of figure 103 viewed frontally and in the maximum screening configuration;

[0133] - figure 108 is a schematic frontal view of a nineteenth embodiment of the screening apparatus of the invention in a maximum screening configuration of the opening;

[0134] - figure 109 is a diagram illustrating a further group of components of the screening apparatus of figure 108 in a maximum screening configuration of the opening;

[0135] - figure 110 is a diagram illustrating a further group of components of the screening apparatus of figure 108 in a maximum screening configuration of the opening;

[0136] - figure 111 is a partial view in section of the screening apparatus of figure 108 along section plane B-B of figure 108;

[0137] - figure 112 is a partial view of the screening apparatus of figure 108 along section plane A-A of figure 108;

[0138] - figure 113 is a schematic frontal view of a twentieth embodiment of the screening apparatus of the invention in a maximum screening configuration of the opening;

[0139] - figure 114 is a diagram illustrating a group of components of the screening apparatus of figure 113 in a maximum screening configuration of the opening;

[0140] - figure 115 is a diagram illustrating a further group of components of the screening apparatus of figure 113 in a maximum screening configuration of the opening;

[0141] - figure 116 is a partial view in section of the screening apparatus of figure 113 along section plane B-B of figure 113;

[0142] - figure 117 is a partial view of the screening apparatus of figure 113 along section plane A-A of figure 113.

[0143] DESCRIPTION OF PREFERRED EMBODIMENTS

[0144] Note that, for the sake of clarity, in the figures illustrating sections, not all the shading of the sectioned components of the screening apparatuses has been done. Further, in some figures, some components have been drawn as if they were transparent in order to highlight underlying components which otherwise would not be visible. In the figures relating to the invention (from figure 10 onwards), numerical reference (1) denotes a screening apparatus for screening an opening, which opening is rectangular and comprises a first side (3) which is vertical. Note that in line with the geometrical definitions, the term “rectangular” also covers the term “square”.

[0145] The screening apparatus (1) of the invention has the following characteristics:

[0146] - it comprises a frame;

[0147] - it comprises a first housing (2) which is part of the frame and which is vertically positionable at the first side (3) of the opening;

[0148] - it comprises a winding roller (4) (see figure 31) which is housable vertically in the first housing (2) so as to rotate with respect to the axis thereof;

[0149] - it comprises a screen cloth (5) which comprises: a first edge which is fixed to the winding roller (4) so that the screen cloth (5) can be wound on, and be unwound from, the winding roller (4); a second edge opposite the first edge; a third edge (6) which is interposed between the first edge and the second edge;

[0150] - it comprises a first guide unit (7), (preferably a guide chain), for inferiorly guiding the screen cloth (5); which first guide unit: is couplable to the third edge (6) of the screen cloth (5); extends in a longitudinal direction; which first guide unit: comprises a first end (38), which is fixable (and, preferably, is fixed) to the frame in proximity of the lower part of the first side (3) of the opening or at the lower part of the first side (3) of the opening; comprises a second end (39) opposite the first end (38) (see figures 13, 35, 36, 45, 46); and can flex along the extension thereof so as to form at least a straight section and at least a curved section;

[0151] - comprises a sliding bar (11) which: is fixable to the second edge of the screen cloth (5); comprises a first end portion (12) and a second end portion (13), which is opposite the first end portion (12); comprises a first guide channel (16) (see figure 98, which illustrates the empty first guide channel) for guiding at least a variable part of the first guide unit (7) which is decoupled from the third edge (6) of the screen cloth (5). The first guide channel (16) originates at the first end portion (12) of the sliding bar (11) (preferably at the side thereof which is facing the first housing (2)), extends in the sliding bar (11) and comprises: a first guide portion (25), which originates at the first end portion (12) of the sliding bar (11) and which is at least partially curved; a second guide portion (26) which originates from the first guide portion (25) of the first guide channel (16), which is straight (and preferably vertical) and which extends towards the second end portion (13) of the sliding bar (11).

[0152] The first guide channel (16) (see figure 98) further comprises: a third guide portion (27), which originates from the second guide portion (26) of the first guide channel (16), which is arranged in the second end portion (13) of the sliding bar (11) and which is curved; a fourth guide portion (28), which originates from the third guide portion (27) of the first guide channel (16), which is straight (and preferably vertical) and which extends towards the first end portion (12) of the sliding bar (11). The first guide channel (16) is configured for slidably receiving and flexing the variable part of the first guide unit (7) during a first activation of the sliding bar (11) along a screening plane (21) aimed at reducing the screening of the opening, in such a way that the second end (39) of the first guide unit (7) can slide in succession in the first guide portion (25) of the first guide channel (16), the second guide portion (26) of the first guide channel (16), the third guide portion (27) of the first guide channel (16) and the fourth guide portion (28) of the first guide channel (16).

[0153] In an activation of the sliding bar (11) aimed at reducing the screening of the opening to a minimum, the first guide unit (7) can progressively form (see figures 14, 46 and 98): a first section (14) of the first guide unit (7) which is at least partially curved, in the first guide portion (25) of the first guide channel (16); a second section (15) of the first guide unit (7), which is straight, in the second guide portion (26) of the first guide channel (16); a third section (72) of the first guide unit (7), which is curved, in the third guide portion (27) of the first guide channel (16); and a fourth section (73) of the first guide unit (7) (see figure 14), which is straight and which comprises the second end (39) of the first guide unit (7), and in the fourth guide portion (28) of the first guide channel (16).

[0154] The winding roller (4) can comprise an elastic recall means, not illustrated, for automatically winding the cloth, such as for example a preloaded recall spring.

[0155] The first guide portion (25) of the first guide channel (16) preferably comprises a single concavity facing towards the second end portion (13) of the sliding bar (11) and the third guide portion (27) of the first guide channel (16) comprises a single concavity facing towards the first end portion (12) of the sliding bar (11 ).

[0156] By way of non-limiting example, a guide unit (7) can have a relative length comprised between 1 and 2 times the extension of the first side (3) of the opening.

[0157] As illustrated in the figures relating to the invention, the first guide unit (7) preferably comprises or is a guide chain. This can comprise a plurality of chain elements, in which each of the elements of the chain of the plurality of first guide chain elements has a relative guide portion that is facing upwards and is engageable to the third edge (6) of the screen cloth (5).

[0158] Note that the first activation can be either manual or motorised and, preferably, is manual.

[0159] The first guide channel (16) is advantageously entirely sectioned by the first screening plane (21).

[0160] With reference to figures 25-33, 36, 40, 45-47, 50, 53, 56, 61 , 66, 72, 74-86 and 92-96, with the aim of keeping the sliding bar (11) in the vertical position during each relative activation, the screening apparatus (1) according to the invention preferably comprises a compensating unit (10.24) (preferably a compensating chain or a compensating belt): which extends in a longitudinal direction; which comprises a first end (40) and a second end (41) opposite the first end (40). The first end (40) is fixable (and is preferably fixed) to the frame, in proximity of the upper part of the first side (3) of the opening or fixed at the upper part of the first side (3) of the opening. The compensating unit (10, 24) can flex along the extension thereof to form: at least a straight section and at least a curved section. In this case, the sliding bar (11) further comprises a second guide channel (17) for guiding at least a variable part of the compensating unit (10, 24) (see figure 97, which illustrates the empty second guide channel).

[0161] The second guide channel (17) originates at the second end portion (13) of the sliding bar (11) (preferably on the side thereof which is opposite the first housing) and extends in the sliding bar (11). The second guide channel (17) comprises: a first guide portion (29), which originates at the second end portion (13) of the sliding bar (11) and which is at least partially curved; a second guide portion (30) which originates from the first guide portion (29) of the second guide channel (17), which is straight (and preferably vertical) and which extends towards the first end portion (12) of the sliding bar (11); a third guide portion (31), which originates from the second guide portion (30) of the second guide channel (17), which is arranged in the first end portion (12) of the sliding bar (11) and which is curved; a fourth guide portion (32), which originates from the third guide portion (31) of the second guide channel (17), which is straight (and preferably vertical) and which extends towards the second end portion (13) of the sliding bar (11). The second guide channel (17) is configured for slidably receiving and flexing the variable part of the compensating unit (10, 24) during the first activation of the sliding bar (11) along a screening plane (21) aimed at reducing the screening of the opening, in such a way that the second end (41) of the compensating unit (10) can slide in succession into the first guide portion (29) of the second guide channel (17), the second guide portion (30) of the second guide channel (17), the third guide portion (31) of the second guide channel (17) and the fourth guide portion (32) of the second guide channel (17).

[0162] In this case, when the first housing (2) is positioned vertically at the first side (3) of the opening with the winding roller (4) housed thereat and with the sliding bar (11) and which is vertical and which is fixed to the second edge of the screen cloth (5), the first guide channel (16) and the second guide channel (17) are entirely arranged on opposite sides with respect to a vertical plane (23) passing through the sliding bar (11) and parallel to the screening plane (21) (see figures 31 and 44). In this case, the screening apparatus (1) further comprises a synchronising unit for synchronising the sliding of the variable part of the first guide unit (7) in the first guide channel (16) and of the variable part of the compensating unit (10, 24) in the second guide channel (17). The synchronising unit is connectable to the first guide unit (7) and to the compensating unit (10, 24). The compensating unit (10, 24) and the synchronising unit are configured in such a way as, in use, to maintain the sliding bar (11) vertically orientated during a second, and any, activation of the sliding bar (11) along the screening plane (21) and aimed at increasing or reducing the screening of the opening.

[0163] In an activation of the sliding bar (11) aimed at reducing the screening of the opening to a minimum, the compensating unit (10, 24) can progressively form (see figures 25, 45 and 97): a first section (74) of the compensating unit (10, 24) which is at least partially curved, in the first guide portion (29) of the second guide channel (17); a second section (75) of the compensating unit (10, 24), which is straight, in the second guide portion (30) of the second guide channel (17); a third section (76) of the compensating unit (10, 24), which is curved, in the third guide portion (31) of the second guide channel (17); and a fourth section (77) of the compensating unit (10, 24), which is straight and which comprises the second end (41) of the compensating unit (10, 24), in the fourth guide portion (32) of the second guide channel (17).

[0164] The first guide portion (29) of the second guide channel (17) each preferably comprises a single concavity facing towards the first end portion (12) of the sliding bar (11) and the third guide portion (31) of the second guide channel (17) comprises a single concavity facing towards the second end portion (13) of the sliding bar (11). The compensating unit (10, 24) will advantageously have the same length as the first guide unit.

[0165] According to the invention, the first guide channel (16) and the second guide channel (17) are entirely arranged on opposite sides with respect to a vertical plane (23) passing through the sliding bar (111) and parallel to the screening plane (21) (see figures 31 and 44). Therefore, the fourth edge (8) of the screen cloth (5), which is opposite the third edge (6) and which is located on the screening plane (21), is accessible. It is therefore possible to use a second guide unit (37), including of the traditional type with brushes, to guide the fourth edge (8) of the screen cloth (5). In this way, in the maximum screening configuration of the screening apparatus, the fourth edge (8) is prevented from displacing from the screening plane (21) and the passage of insects is effectively obstructed.

[0166] The fourth guide portion (28) of the first guide channel (16) preferably has a length (402) is smaller or equal to the length (401) of the second guide portion (26) of the first guide channel (16).

[0167] More preferably, the length (402) of the fourth guide portion (28) is equal to the length (401) of the second guide portion (26) of the first guide channel (16), with the second and the fourth guide portion (26, 28) of the first guide channel (16) which both extend from the first end portion (11) to the second end portion (12) of the sliding bar (11). This enables exploiting to a maximum the extension of the sliding bar (11). The distance (or “stroke”) that the sliding bar (11) shifts, between the minimum screening configuration and the maximum screening configuration, corresponds to the length of the section of the first guide unit (7) which engages with the third edge (6) in the maximum screening configuration and thus to the horizontal extension (400) of the maximum screening portion of the screen cloth (5) (see figures 11-14). The distance (or stroke), when the length (402) of the fourth guide portion (28) is equal to the length (401) of the second guide portion (26) of the first guide channel (16), is given by the sum of twice the length (401) of the second guide portion (26) of the first guide channel (16) and of the length (402) of the third guide portion (27) of the first guide channel (16). This sum is thus close to (but always lower) than twice the height of the opening to be screened. Likewise, the fourth guide portion (32) of the second guide channel (17) can have a length that is shorter than or equal to the second guide portion (30) of the second guide channel (17), and, more preferably, is equal, with both the guide portions (30, 32) of the second guide channel (17) extending from the first end portion (11) to the second end portion (12) of the sliding bar (11).

[0168] The compensating unit (10, 24) can advantageously be a selected from: a compensating chain (10) (see for example figures 25-74, 84 and 85), which is flexible and which comprises a plurality of second chain elements; and a flexible metal strap (24) having a transversal section, with respect to the screening plane (21), which has a concavity facing downwards (see figures 75-77), as in the prior art.

[0169] In a particularly preferred embodiment of the invention (see figures 44, 56-74 and 97-98), the synchronising unit can comprise:

[0170] - a first plurality of synchronising channels, in turn comprising: a first synchronising channel (78) (see figures 46 and 98): which is arranged in the first end portion (12) of the sliding bar (11); which conjoins (preferably inferiorly) the second guide portion (26) of the first guide channel (16) and the fourth guide portion (28) of the first guide channel (16) to one another and which is preferably curved; - a second synchronising channel (79) (see figures 45 and 97): which is arranged in the second end portion (13) of the sliding bar (11); which conjoins (preferably superiorly) the second guide portion (30) of the second guide channel (17) and the fourth guide portion (32) of the second guide channel (17) to one another; and which is, preferably, curved;

[0171] - a third synchronising channel (80) (see figures 56, 59, 64, 69, 72 and 74): which is arranged in the first end portion (12) of the sliding bar (11); and which conjoins (preferably inferiorly) the second guide portion (26) of the first guide channel (16) and the fourth guide portion (32) of the second guide channel (17) to one another; and which is preferably straight;

[0172] - a fourth synchronising channel (81) (see figures 56, 60, 65, 70, 72 and 74): which is arranged in the second end portion (13) of the sliding bar (11); which conjoins (preferably superiorly) the fourth guide portion (28) of the first guide channel (16) and the second guide portion (30) of the second guide channel (17) to one another; and which is preferably straight;

[0173] - a first cable (380) (see figures 57, 62, 67 and 72): which is insertable in the first plurality of synchronising channels, in the first guide channel (16) and in the second guide channel (17); which can flex along the extension thereof to form at least a straight section and at least a curved section; which comprises a first end, which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which comprises a second end, which is opposite the first end of the first cable (380), which is fixed to the second end (41) of the compensating unit (10, 24) arranged in the second guide channel (17); and which is preferably stretched;

[0174] - a second cable (381) (see figures 58, 63, 67, 68 and 73): which is insertable in the first plurality of synchronising channels, in the first guide channel (16) and in the second guide channel (17); which can flex along the extension thereof to form: at least a straight section and at least a curved section; which comprises a first end, which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which comprises a second end, which is opposite the first end of the second cable (381), which is fixed to the second end (41) of the compensating unit (10, 24) arranged in the second guide channel (17); and which is preferably stretched.

[0175] In the first embodiment the first cable (380), in a minimum screening configuration of the screening apparatus (1) (see figures 61 and 62), can comprise:

[0176] - a first portion (82), which comprises the first end of the first cable (380); and which is arranged in the fourth guide portion (28) of the first guide channel (16);

[0177] - a second portion (83): which originates from the first portion (82) of the first cable (380); and which is arranged in the first synchronising channel (78);

[0178] - a third portion (84): which originates from the second portion (83) of the first cable (380); and which is arranged in the second guide portion (26) of the first guide channel (16) and in the third guide portion (27) of the first guide channel

[0179] (16);

[0180] - a fourth portion (85): which originates from the third portion (84) of the first cable (380); and which is arranged in the fourth synchronising channel (81);

[0181] - a fifth portion (86): which originates from the fourth portion (85) of the first cable (380); which is arranged in the second guide portion (30) of the second guide channel (17), in the third guide portion (31) of the second guide channel (17) and in the fourth guide portion (32) of the second guide channel (17); and which comprises the second end of the first cable (380).

[0182] Again in the same embodiment, the second cable (381), in the minimum screening configuration of the screening apparatus (1) (see figures 61 and 63), can comprise:

[0183] - a first portion (87): which comprises the second end of the second cable (381); and which is arranged in the fourth guide portion (32) of the second guide channel

[0184] (17);

[0185] - a second portion (88): which originates from the first portion (87) of the second cable (381); and which is arranged in the second synchronising channel (79);

[0186] - a third portion (89): which originates from the second portion (88) of the second cable (381); and which is arranged in the second guide portion (30) of the second guide channel (17) and in the third guide portion (31) of the second guide channel (17);

[0187] - a fourth portion (90): which originates from the third portion (89) of the second cable (381); and which is arranged in the third synchronising channel (80);

[0188] - a fifth portion (91): which originates from the fourth portion (90) of the second cable (381); which is arranged in the second guide portion (26) of the first guide channel (16), in the third guide portion (27) of the first guide channel (16) and in the fourth guide portion (28) of the first guide channel (16); and which comprises the first end of the second cable (381).

[0189] Note that figures 57 and 67 schematically illustrate the arrangement of the first cable (380) respectively in the minimum, intermediate and maximum screening configurations. Figures 58 and 68 schematically illustrate the arrangement of the second cable (381) respectively in the intermediate and maximum screening configurations. The arrangement of the first cable (380) and the second cable (381) in the intermediate and maximum screening configurations is obtained automatically following a corresponding activation of the sliding bar (11). Note that figures 57, 58, 62, 63, 67, 68 are diagrams. In these figures, numerical reference (506) denotes a first global surface which comprises: the inner surface of the first guide channel (16); the inner surface of the second guide channel (17); the inner surface of the first synchronising channel (78) the inner surface of the second synchronising channel (79); the surface of the third synchronising channel (80); and the surface of the fourth synchronising channel (81). In the various configurations of the screening apparatus (1) of this embodiment, the first global surface contacts, at least partially and differently, the first cable (380) and the second cable (381).

[0190] The first synchronising channel (78) is preferably curved with a single concavity facing towards the second end portion (13) of the sliding bar (11); further, the second synchronising channel (79) is curved with a single concavity facing towards the first end portion (12) of the sliding bar (11). The third synchronising channel (80) is preferably straight; further, the fourth synchronising channel (81) is straight.

[0191] Alternative and advantageous embodiments of the invention are illustrated in figures 47-55, 103-107, 108-112 and 113-117, wherein, for reasons of clarity, only some of the components of the screening apparatus of the invention have been illustrated schematically. According to these embodiments, the synchronising unit can comprise a second plurality of synchronising channels, in turn comprising:

[0192] - a fifth synchronising channel: which is arranged in the first end portion (12) of the sliding bar (11) and which conjoins (preferably inferiorly) the second guide portion (26) of the first guide channel (16) and the fourth guide portion (28) of the first guide channel (16) to one another; and is preferably curved;

[0193] - a sixth synchronising channel which: is arranged in the second end portion (13) of the sliding bar (11); superiorly conjoins the second guide portion (30) of the second guide channel (17) and the fourth guide portion (32) of the second guide channel (17) to one another; and which, preferably, is curved;

[0194] - a third cable (95) (see figures 48, 51 54, 104, 105, 109, 111 , 114 and 116): which is insertable in the second plurality of synchronising channels, in the first guide channel (16), and in the second guide channel (17); which can flex along the extension thereof to form at least a straight section and at least a curved section; which comprises a first end which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which comprises a second end, which is opposite the first end of the third cable (95) and fixed to the second end (41) of the compensating unit (10, 24) arranged in the second guide channel (17); and which is preferably stretched;

[0195] - a first upper direction inversion element (94) which: is arranged in the second end portion (13) of the sliding bar (11); windingly receives the third cable (95); is arranged and dimensioned in such a way that the third cable (95) can be arranged in the second guide portion (26) of the first guide channel (16), can wind about the first upper direction inversion element (94) and can be arranged in the second guide portion (30) of the second guide channel (17);

[0196] - a fourth cable (96) (see figures 49, 52, 55, 106, 107, 110, 112 115 and 117): which is insertable in the second plurality of synchronising channels, in the first guide channel (16) and in the second guide channel (17); which can flex along the extension thereof to form at least a straight section and at least a curved section; which comprises a first end which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which comprises a second end, which is opposite the first end of the fourth cable (96) and fixed to the second end (41) of the compensating unit (10, 24) arranged in the second guide channel (17); and which, preferably, is stretched;

[0197] - a first lower direction inversion element (93): which is arranged in the first end portion (12) of the sliding bar (11); which windingly receives the fourth cable (96); which is arranged and dimensioned in such a way that the fourth cable (96) can be arranged in the second guide portion (30) of the second guide channel (17), can wind about the first lower direction inversion element (93) and can be arranged in the second guide portion (26) of the first guide channel (16).

[0198] Note that the fifth synchronising channel has not been illustrated in the figures and that the fifth synchronising channel is identical to the first synchronising channel (78), which is illustrated in figures 46 and 98.

[0199] Note that the sixth synchronising channel has not been illustrated in the figures and that the sixth synchronising channel is identical to the second synchronising channel (79), which is illustrated in figures 45 and 97.

[0200] In the latter described embodiment, the third cable (95), in a minimum screening configuration of the screening apparatus (1) (see figures 47 and 48), can comprise:

[0201] - a first portion (97): which comprises the first end of the third cable (95); and which is arranged in the fourth guide portion (28) of the first guide channel (16);

[0202] - a second portion (98): which originates from the first portion (97) of the third cable (95); and which is arranged in the fifth synchronising channel;

[0203] - a third portion (99): which originates from the second portion (98) of the third cable (95); and which is arranged in the second guide portion (26) of the first guide channel (16) and, optionally, in the third guide portion (27) of the first guide channel (16);

[0204] - a fourth portion (201): which originates from the third portion (99) of the third cable (95); and which winds about the first upper direction inversion element (94);

[0205] - a fifth portion (202): which originates from the fourth portion (201) of the third cable (95); which is arranged in the second guide portion (30) of the second guide channel (17), in the third guide portion (31) of the second guide channel (17) and in the fourth guide portion (32) of the second guide channel (17); and which comprises the second end of the third cable (95).

[0206] The fourth portion (201) of the third cable (95) can advantageously be external of the first guide channel (16) and in the second guide channel (17).

[0207] In the above-described embodiment, the fourth cable (96), in the minimum screening configuration of the screening apparatus (1) (see figures 47 and 49), can comprise:

[0208] - a first portion (203): which comprises the second end of the fourth cable (96); and which is arranged in the fourth guide portion (32) of the second guide channel (17);

[0209] - a second portion (204): which originates from the first portion (203) of the fourth cable (96); and which is arranged in the sixth synchronising channel;

[0210] - a third portion (205): which originates from the second portion (204) of the fourth cable (96); and which is arranged in the second guide portion (30) of the second guide channel (17); and, optionally, in the third guide portion (31) of the second guide channel (17);

[0211] - a fourth portion (206): which originates from the third portion (205) of the fourth cable (96); and which winds about the first lower direction inversion element (93);

[0212] - a fifth portion (207); which originates from the fourth portion (206) of the fourth cable (96); which is arranged in the second guide portion (26) of the first guide channel (16), in the third guide portion (27) of the first guide channel (16) and in the fourth guide portion (28) of the first guide channel (16); and which comprises the first end of the fourth cable (96).

[0213] The fourth portion (206) of the fourth cable (96) can advantageously be external of the first guide channel (16) and in the second guide channel (17).

[0214] The first upper direction inversion element (94) can preferably be arranged externally of the first guide channel (16) and externally of the second guide channel (17). Further, the first lower direction inversion element (93) can preferably be arranged externally of the first guide channel (16) and externally of the second guide channel (17).

[0215] As illustrated in figures 108-116), the screening device (1) of the invention can advantageously comprise: a third housing (300), in which the first upper direction inversion element (94) is arranged; a seventh synchronising channel (301), which connects the third housing (300) to the first guide channel (16) (preferably at the second guide portion (26) of the first guide channel (16)); and an eighth synchronising channel (302) which connects the third housing (300) to the second guide channel (17) (preferably at the second guide portion (30) of the second guide channel (17)). Further, as illustrated in figures 108-117, the screening device (1) of the invention can advantageously comprise: a fourth housing (305), in which the first upper direction inversion element (94) is arranged; a ninth synchronising channel (303), which connects the fourth housing (30) to the first guide channel (16) (preferably at the second guide portion (26) of the first guide channel (16)); and a tenth synchronising channel (304), which connects the third housing (300) to the second guide channel (17) (preferably at the second guide portion (30) of the second guide channel (17)).

[0216] Note that figures 51 and 54 schematically illustrate the arrangement of the third cable (95) respectively in the intermediate and maximum screening configurations. Figures 52 and 55 schematically illustrate the arrangement of the second cable (96) respectively in the intermediate and maximum screening configurations. The arrangement of the third cable (95) and the fourth cable (96) in the intermediate and maximum screening configurations is obtained automatically following a corresponding activation of the sliding bar (11). Note that figures 48, 49, 51 , 52, 54, 55, 104-107, 109, 1010, 114 and 115 are diagrams in which reference numeral (505) denotes a second global surface which comprises: the inner surface of the first guide channel (16); the inner surface of the second guide channel (17); the inner surface of the fifth synchronising channel; the inner surface of the sixth synchronising channel. In the various configurations of the screening apparatus (1) of these embodiments, the second global surface contacts (505) contacts, at least partially and differently, the third cable (95) and the fourth cable (96).

[0217] The first guide unit (7) and to the compensating unit (10, 24) are preferably not insertable either in the first plurality of synchronising channels or in the second plurality of synchronising channels.

[0218] Note that relatively to the first, second, third, fourth, fifth and sixth synchronising channel (78, 79, 80, 81), the terms “inferiorly” and “superiorly”, used in relation to the verb “conjoin”, are clearly meant with the sliding bar vertically orientated.

[0219] The verb “wind”, used in relation to the synchronising cables, can indicate a winding that is at least partial or a total winding, or preferably indicates a partial winding.

[0220] The screening apparatus (1) of the invention preferably further comprises a second housing (42), which is part of the frame, and which is horizontally positionable at a second side (62) of the opening, which originates from the upper part of the first side (3) of the opening; wherein, in the second housing (42), when positioned horizontally, the following are contemporaneously housable: at least partially, the compensating unit (10, 24), positioned horizontally; and the second end portion (13) of the sliding bar (11), with freedom to slide relatively between the second end portion (13) of the sliding bar (11 ) and the second housing (42).

[0221] In this case, in order to reduce the flexion of the compensating unit (10, 24) in the maximum screening configuration, especially when it is a compensating chain (10), it is preferable for the screening apparatus (1) according to the invention to comprise at least a first brush (48) (see figures 78-80): which extends in a longitudinal direction; which is, preferably, arranged horizontally in the second housing (42); which is arranged parallel to the screening plane (21); which comprises bristles that are configured and arranged to inferiorly support the compensating unit (10, 24) housed in the second housing (42), wherein the at least a first brush (48) is arranged in one of following positions: on a first longitudinal side of the compensating unit (10, 24) housed in the second housing (42) (see figure 78); on a second longitudinal side of the compensating unit (10, 24) housed in the second housing (42), which is opposite the first longitudinal side (see figure 79); or when the at least a first brush (48) is a first pair of first brushes (48), (see figure 80), on both the first and the second longitudinal side of the compensating unit (10, 24) (which is preferably a compensating chain), housed in the second housing (42).

[0222] For this purpose, the screening apparatus (1) can comprise at least a first groove (700) which extends in a longitudinal direction; which is positioned horizontally in the second housing (42); and wherein at least a first brush (48) is insertable on the opposite side to the one where the relative bristles are arranged. Obviously, when the at least a first brush (48) is a first pair of first brushes (48) (see figure 80), the screening apparatus (1) can comprise a pair of first grooves (700), at which each of the first grooves (700) is positioned at a different longitudinal side of the compensating unit (10, 24). Note, in this matter, that the at least a first groove (700) can be advantageously arranged at the inner surface of a longitudinal wall of the second housing (42) which, preferably, is parallel to the screening plane (21).

[0223] Alternatively to the compensating unit, the screening apparatus (1) of the invention can comprise a first partial compensating unit (see figures 17-20), in turn comprising:

[0224] - a second lower direction inversion element (208) which is arranged in the first end portion (12) of the sliding bar (11);

[0225] - a second upper direction inversion element (209) which is arranged in the second end portion (13) of the sliding bar (11 );

[0226] - a fifth cable (210): which has a first end which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which has a second end opposite the first end, and which is fixable to the frame in proximity of the upper part of a third side (61) of the opening opposite the first side (3) of the opening or which is fixable to the upper part of the third side (61) of the opening; and which is arranged in such a way that, starting from the relative second end, winds about the second upper direction inversion element (209), winds about the second lower direction inversion element (208) and enters the first guide channel (16).

[0227] As can be observed in figures 17-20, the fifth cable (210) again has: a portion that is external of the first guide channel (16); a portion that is internal of the first guide channel (16), which is minimum in the minimum screening configuration (see figure 19) and which is maximum in the maximum screening configuration (see figure 20). The arrangement of the fifth cable (210) in the minimum, intermediate and maximum screening configurations is obtained automatically following a corresponding activation of the sliding bar (11 ). Note that the inner convex surface of the third guide portion (27) of the first guide channel (16) functions as a further direction inversion element for the fifth cable (210). The portion of the fifth cable (210) is wound on the further direction inversion element which is internal of the first guide channel (16) when, during an activation of the sliding bar (11) aimed at increasing the screening of the screening apparatus (1), the second end (39) of the first guide unit (7), which originates from the fourth guide portion (28) of the first guide channel (16), runs along the third guide portion (27) of the first guide channel (16) towards the second guide portion (26) of the first guide channel (16).

[0228] The second lower direction inversion element (208) can preferably be arranged externally of the first guide channel (16). Further, the second upper direction inversion element (209) can be arranged externally of the first guide channel (16).

[0229] The fifth cable (210) can advantageously be stretched to prevent a rotation in a first direction of the sliding bar (11 ) on the screening plane (21 ) following a second activation of the sliding bar (11) along the screening plane (21) and aimed at increasing or reducing the screening of the opening. In fact, with reference to figure 17, the first partial compensating unit enables compensating a rotation of the sliding bar in an anti-clockwise direction which might occur when, for example, if the sliding bar (11) were gripped from above to reduce the screening in the absence of the first partial compensating unit.

[0230] Again, with reference to figure 17, note that the first compensating unit is not able to compensate, even partially, a rotation of the sliding bar in clockwise direction which might occur if the sliding bar (11) were gripped from above to increase the screening. Therefore, the user desiring to increase the screening will preferably have to grip the sliding bar (11) centrally to easily increase the screening.

[0231] Alternatively to the first partial compensating unit, the screening apparatus (1) of the invention can comprise a second partial compensating unit (see figures 21- 24), in turn comprising:

[0232] - a third lower direction inversion element (213) arranged in the first end portion (12) in the sliding bar (11);

[0233] - a third upper direction inversion element (214) which is arranged in the second end portion (13) of the sliding bar (11);

[0234] - a sixth cable (215): which has a first end which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which has a second end opposite the first end, and which is fixable to the frame in proximity of the upper part of the first side (3) of the opening or which is fixable to the upper part of the first side (3) of the opening; and which is arranged in such a way that, starting from the relative second end, winds about the third upper direction inversion element (214), winds about the third lower direction inversion element (213) and enters the first guide channel (16).

[0235] As can be observed in figures 21-24, the sixth cable (215) still has: a portion that is external of the first guide channel (16); and a portion that is internal of the first guide channel (16). The internal portion is minimum in the maximum screening configuration (see figure 24) and is maximum in the minimum screening configuration (see figure 23). The arrangement of the sixth cable (215) in the minimum, intermediate and maximum screening configurations is obtained automatically following a corresponding activation of the sliding bar (11).

[0236] Note that the inner convex surface of the third guide portion (27) of the first guide channel (16) functions as a still further direction inversion element for the sixth cable (215). The portion of the sixth cable (215) is wound on the still further direction inversion element which is internal of the first guide channel (16) when, during an activation of the sliding bar (11) aimed at reducing the screening of the screening apparatus (1), the second end (39) of the first guide unit (7), which originates from the second guide portion (26) of the first guide channel (16), runs along the third guide portion (27) of the first guide channel (16) towards the fourth guide portion (2) of the first guide channel (16).

[0237] The third lower direction inversion element (213) can preferably be external of the first guide channel (16). Further, the third upper direction inversion element (214) can preferably be external of the first guide channel (16).

[0238] The sixth cable (215) can advantageously be stretched, preventing a rotation in a second direction (opposite the first direction) of the sliding bar (11) on the screening plane (21) following a second activation of the sliding bar (11) along the screening plane (21) and aimed at increasing or reducing the screening of the opening.

[0239] An advantageous embodiment of the apparatus according to the invention (not illustrated) which comprises both the first partial compensating unit (see figures 17-20) and the second partial compensating unit (see figures 21-24) for overall obtaining a compensating unit which comprises and, preferably, is constituted by the first partial compensating unit and by the second partial compensating unit and which is able to maintain the sliding bar (11) constantly vertical during an activation of the sliding bar (11) aimed at reducing or increasting the screening of the screening apparatus (1), whether the sliding bar (1) is gripped superiorly or inferiorly. In fact, it prevents both a rotation in the first and second direction of the sliding bar (11) on the screening plane (21) following a second activation of the sliding bar (11) along the screening plane (21) and aimed at increasing or reducing the screening of the opening. Note that, in that case, the third lower direction inversion element (213) can advantageously be constituted by the second lower direction inversion element (208). Further, the third upper direction inversion element (214) can be constituted by the second upper direction inversion element (209).

[0240] Note that the first upper direction inversion element (94), the first lower direction inversion element (93), the second lower direction inversion element (208), the second upper direction inversion element (209), the third lower direction inversion element (213) and the third upper direction inversion element (214), can be relays, i.e. idler rollers, having a relative rotation axis preferably arranged parallel to the screening plane (21) (see figures 113-117) or more advantageously, perpendicularly to the screening plane (21) (see figures 17-24, 47-55, 103-107). Alternatively, the first upper direction inversion element (94), the first lower direction inversion element (93), the second lower direction inversion element (208), the second upper direction inversion element (209), the third lower direction inversion element (213) and the third upper direction inversion element (214), can be cylindrical elements having a relative axis preferably arranged parallel, or more preferably, perpendicularly, to the screening plane (21).

[0241] The first guide unit (7), which can more preferably be a guide chain, can preferably comprise engaging elements, arranged at the screening plane (21) and engageable to the third edge (6) of the screen cloth (5).

[0242] Particularly preferred is a screening apparatus (1) according to the invention, in which the first guide unit (7) is a first guide chain (7) (see figures 90-91). It comprises a first plurality of guide chain elements, in which each of the guide chain elements (221 , 248, 249, 250) of the first plurality of guide chain elements is hingeable at a first hinge axis (222) and at a second hinge axis (223), parallel to one another, and comprises:

[0243] - a bottom (228) positionable resting on a horizontal support plane; wherein the first hinge axis (222) and the second hinge axis (223) are arranged at a first height from the support plane;

[0244] - first engaging elements (226) for coupling to the third edge (6) of the screen cloth (5) and along a coupling direction which is perpendicular to the first hinge axis (222); wherein the first engaging elements (226) are arranged on an opposite side to the bottom (228) at a second height from the support plane which is lower than the first height;

[0245] - a first longitudinal wall (224) (see figures 88 and 89): arranged perpendicular to the bottom (228) and to the first hinge axis (222); and comprises a first portion (225) having a first thickness and a second portion (227) having a second thickness which is smaller than the first thickness, wherein the first portion (225) of the first longitudinal wall (224): comprises a first tapered projecting region (229) (visible in figure 88), which has a first convex edge (230) and which projects with respect to a first side of the first engaging elements (226) (see figure 88) which is parallel to the first hinge axis (222); comprises a first chain element (331) arranged at the first hinge axis (222); and wherein the first portion (225) of the first longitudinal wall (224) further comprises a first concave edge (232) (see figure 89) opposite the first convex edge (230) and complementary to the first convex edge (230), wherein the second portion (227) of the first longitudinal wall (224) originates from the first concave edge (232) of the first portion (225) of the first longitudinal wall (224) and comprises a second chain element (240) arranged at the second hinge axis (223);

[0246] - a second longitudinal wall (233) (see figures 87 and 88) opposite the first longitudinal wall (224) which comprises: a first portion (234) having a third thickness; a second portion (235) having a fourth thickness which is smaller than the third thickness; a third portion (236) having the third thickness and a fourth portion (237) having the fourth thickness; wherein the first portion (234) of the second longitudinal wall (233) has a second tapered projecting region (238) (see figure 87): which has a second convex edge (239); which projects with respect to the first side of the first engaging elements (226); which comprises a third chain element (241) arranged at the first hinge axis (222); and wherein the first portion

[0247] (234) of the second longitudinal wall (233) further comprises a second concave edge (244) (see figure 87) opposite the second convex edge (239) and complementary to the second convex edge (239), wherein the second portion

[0248] (235) of the second longitudinal wall (233) originates from the second concave edge (244) and comprises a fourth chain element (242) arranged at the second hinge axis (223) wherein the third portion (236) of the second longitudinal wall (233) is arranged inferiorly of the second portion (235) of the second longitudinal wall (233) and has a third tapered projecting region (245): which has a third convex edge (246), which projects with respect to a second side of the first engaging elements (226) opposite the first side of the first engaging elements (226); wherein the third portion (236) of the second longitudinal wall (233) further comprises a third concave edge (247) (see figure 88) opposite the third convex edge (246) and complementarily profiled with respect to the third convex edge (246), wherein the fourth portion (237) of the second longitudinal wall (233) originates from the third concave edge (247) and is arranged inferiorly of the first portion (234) of the second longitudinal wall (233).

[0249] In this embodiment (see figures 90-91), the first chain element (331) and the third chain element (241) of a first guide chain element (248) of the first plurality of guide chain elements are hinged, respectively, to the second chain element (240) and to the fourth chain element (242) of a second guide chain element (249) of the first plurality of guide chain elements which, in the first guide chain (7), follows the first guide chain element (248). The second chain element (240) and the fourth chain element (242) of the first guide chain element (248) of the first plurality of guide chain elements are hinged, respectively, to the first chain element (331) and to the third chain element (241) of a third guide chain element (250) of the first plurality of guide chain elements which precedes the first guide chain element (248) in the first guide chain (7). When the first guide chain (7) is flexed along the extension thereof, forming a straight section and at least a curved section (see figures 90 and 91), in the straight section, the first convex edge (230) and the second convex edge (239) of the first guide chain element (248) contact, respectively, the first concave edge (232), and the second concave edge (244) of the second guide chain element (249) and the third convex edge (246) of the first guide chain element (248) contact the third concave edge (247) of the third guide chain element (250). While, in the curved section, the first convex edge (230) and the second convex edge (239) of a further first guide chain element (248) are separated, respectively from the first concave edge (232) and the second concave edge (244) of a further second guide chain element (249) of the first plurality of guide chain elements which, in the first guide chain (7), follows the further first guide chain element (248), and the third convex edge (246) of the first guide chain element (248) is separated from the third concave edge (247) of a further third guide chain element (250) of the first plurality of guide chain elements which, in the first guide chain (7), precedes the further first guide chain element (248).

[0250] Note that, in a first curved section, having one only first curve in a first curve direction (see figure 91), the first tapered projecting region (229) of the first longitudinal wall of a first terminal guide chain element (251) of the first plurality of guide chain elements, facilitates the inserting of the first guide chain (7) in a first curved channel in a first inserting direction concordant to the first curve direction. In a second curve direction, having one second curve in a second direction, opposite the first direction (see figure 90), the third tapered projecting region (245) of the second longitudinal wall (233) of a second terminal guide chain element (252) facilitates the inserting of the first guide chain (7) in a second curved channel in a second inserting direction opposite the first inserting direction.

[0251] In practice, the first tapered projecting region (229) and the third tapered projecting region (245) function as a facilitated entry for inserting the first guide chain (7) in the first or in the second curved channel and, therefore, also in the first guide channel (16).

[0252] Note that in the straight section, the first side of the first engaging elements (226) of each of the guide chain elements (221 , 248, 249, 250) of the first plurality of guide chain elements contacts the second side of the successive guide chain element (221 , 248, 249, 250) of the first plurality of guide chain elements, thus defining an uninterrupted engaging seat. This enables the third edge (6) of the screen cloth to slide without the risk of snagging internally of the first engaging elements (226) of each of the guide chain elements (221 , 248, 249, 250) of the straight section. In this way a uniform and effective seal of the third edge (6) of the screen cloth is obtained, alike to what would occur with a single engaging element in a single body (not illustrated), having the same length as the straight section.

[0253] The first chain element (331) and the third chain element (241) are preferably a hinge hole and the second chain element (240), and the fourth chain element (242) comprise (and preferably are) a hinge pin engageable in the hinge hole. The compensating unit (10, 24) is preferably a new first compensating chain (10) (see figures 84 and 85), comprising a plurality of compensating chain elements wherein each of the compensating chain elements (253, 262, 263, 264) of the plurality of compensating chain elements is hingeable to a third hinge axis (256) and a fourth hinge axis (257), parallel to one another, and comprises:

[0254] - a body (258) comprising; a fifth chain element (255) passing through the third hinge axis (256); a first transversal side of the body (258) perpendicular to the third hinge axis (256); a second transversal side of the body (258) opposite the first transversal side of the body (258),

[0255] - an undercut (259) accessible from the first transversal side of the body (258); and

[0256] - a protuberance (265) which projects from the second transversal side of the body (258), which is housable in the undercut (259) of the body (258) of a further compensating chain element (253) of the plurality of compensating chain elements, and which comprises: a fourth convex edge (270); and a sixth chain element (271).

[0257] The fifth chain element (255) of a first compensating chain element (262) of the plurality of compensating chain elements is hinged to the sixth chain element (271) of a second compensating chain element (263) of the plurality of compensating chain elements which follows it in the first compensating chain. The sixth chain element (271) of the first compensating chain element (262) is hinged to the fifth chain element (255) of a third compensating chain element (264) of the plurality of compensating chain elements which precedes it in the first compensating chain (10). In this way, when the first compensating chain (10) is flexed along the extension thereof, forming a straight section and at least a curved section, in the straight section (see figure 85): - the protuberance (265) of the first compensating chain element (262) is entirely housed in the undercut (259) of the body (258) of the further third compensating chain element (264) with the first transversal side of the body (258) of the third compensating chain element (264) contacting the second transversal side of the body (258) of the first compensating chain element (262); and

[0258] - the protuberance (265) of the second compensating chain element (263) is entirely housed in the undercut (259) of the body (258) of the first compensating chain element (262), with the second transversal side of the body (258) of the second compensating chain element (263) contacting the first side of the body (258) of the first compensating chain element (262).

[0259] While, in the curved section (see figure 84):

[0260] - the protuberance (265) of a further second compensating chain element (263) of the plurality of compensating chain elements that follows, in the first compensating chain (10), a further first compensating chain element (262) of the plurality of compensating chain elements is partially housed in the undercut (259) of the body

[0261] (258) of the further first compensating chain element (262) with the second side of the body (258) of the further second compensating chain element (263) being separated from the first transversal side of the body (258) of the further first compensating chain element (262); and

[0262] - the protuberance (265) of the further first compensating chain element (262) of the plurality of compensating chain elements is partially housed in the undercut

[0263] (259) of the body (258) of a further third compensating chain element (264) of the plurality of compensating chain elements which precedes it in the first compensating chain, with the first transversal side of the body (258) of the further third compensating chain element (264) being separated from the second transversal side of the body (258) of the further first compensating chain element (262).

[0264] Note that the protuberance (265) of a terminal compensating chain element (264) of the plurality of compensating chain elements facilitates the inserting of the compensating chain (10) in a curved channel in an inserting direction. In practice, the protuberance (265) functions as a facilitated entry for inserting the compensating chain (10) in the curved channel, and, therefore also in the second guide channel (17).

[0265] The fifth chain element (255) preferably comprises a pair of through-holes, distanced from one another, wherein a first hole of the pair of holes is arranged on a first longitudinal wall of the body (258) and the second hole of the pair of holes is arranged on a second longitudinal wall of the body (258) which longitudinally delimit the undercut (259). In this case, the sixth chain element (271) of a further compensating chain element (263) comprises a pin which projects from both the longitudinal sides of the protuberance (265) and which is, contemporaneously, housable in the pair of holes.

[0266] With the purpose of effectively supporting the compensating unit (10, 24), an embodiment of the screening apparatus (1) according to the invention is preferred, wherein the compensating unit (10, 24) is a second compensating chain (10) which, preferably, can have the same characteristics as described in the foregoing relative to the first compensating chain, and therefore reference is made to figures 81-86. The second compensating chain (10) comprises a second plurality of compensating chain elements, in which each of the compensating chain elements (253) of the second plurality of compensating chain elements is hingeable at a fifth hinge axis (256) and at a sixth hinge axis (257), parallel to one another, and comprises at least a first through-hole (280), which is parallel to the fifth hinge axis (256) which is accessible in a straight section of the second compensating chain (10) (see figure 85). In this case, the screening apparatus can comprise the second housing (42) which, in turn, comprises at least a second brush (49) (see figure 86): which extends in a longitudinal direction; which is arranged horizontally; which is arranged in the second housing (42) parallel to the screening plane (21); which comprises bristles which are configured and arranged to support the second compensating chain (10) by inserting in the first through-hole (280) of each of the compensating chain elements (253) of the plurality of compensating chain elements of the second compensating chain (10) housed in the second housing (42). The at least a second brush (49) is arranged in one of following positions: on the first side of the second compensating chain (10) housed in the second housing (42); on the second side of the second compensating chain (10) housed in the second housing (42) opposite the first side; or when the at least a second brush (49) is a pair of second brushes, on both the first and the second side of the second compensating chain (10) housed in the second housing (42) (see figure 86). In this matter, the screening apparatus (1) can comprise at least a second groove (701) (see figure 86) which extends in a longitudinal direction; which is arranged horizontally in the second housing (42); and wherein the at least a second brush (49) is insertable on the opposite side to the one where the relative bristles are arranged. Obviously, when the at least a second brush (49) is a first pair of second brushes (49), the screening apparatus (1) can comprise a pair of second grooves (701), in which each of the second grooves (701) is positioned at a different longitudinal side of the compensating unit (10, 24). Note that the at least a second groove (701) can be advantageously positioned at the inner surface of a longitudinal wall of the second housing (42).

[0267] When the first compensating chain (10) coincides with the second compensating chain (10), the protuberance (265) advantageously has a second through-hole (500) which is parallel to the third hinge axis (256) and the body (258) has a third though hole (600) parallel to the third hinge axis (256). When the protuberance (265) of the further first compensating chain element (262) of the plurality of compensating chain elements is housed in the undercut (259) of the body (258) of a further third compensating chain element (264), the second through-hole (500) of the protuberance (265) is accessible from the third though hole (600) of the body (258) (see figure 85) and together they define the first through-hole (280).

[0268] In order for the screen cloth to be entirely guided, a screening apparatus (1) according to the invention is preferred, in which: the screen cloth (5) comprises a fourth edge (8), opposite the third edge (6). The screening apparatus (1) further comprises: a second guide unit (37) (see figures 33, 36, 40 and 78-80) for superiorly guiding the screen cloth. The second guide unit (37) is couplable to a fourth edge (8) of the screen cloth (5), which is opposite the third edge (6) of the screen cloth (5); extends in a longitudinal direction; comprises a first end; comprises a second end opposite the first end. The second guide unit (37) is positionable (and is preferably positioned) horizontally at the second side (62) of the opening, laterally to the compensating unit (10), with the first end of the second guide unit (37) being fixed to the frame, in proximity of the upper part of the first side (3) of the opening or fixed at the upper part of the first side (3) of the opening, and with the second end of the second guide unit (37) being fixed to the frame, in proximity of the upper part of the third side (61) of the opening, in proximity of the upper part of the third side (61) of the opening or fixed to the upper part of the third side (61) of the opening. The screening apparatus (1) can, optionally, comprise the second housing (42). In a case in which the second housing (42) is present and positioned horizontally, also, and contemporaneously at least partially housable, is the second guide unit (37), positioned horizontally and laterally to the compensating unit (10).

[0269] Note that, when the second guide unit (37) is also present, the at least a first groove (700) (see figures 78 and 80) or the at least a second groove (701) (see figure 86) can be arranged at the external surface of a longitudinal wall of the second guide unit (37), as the second guide unit (37) is arranged at a side of the compensating unit (10, 24). The longitudinal wall of the second guide unit (37) is advantageously parallel to the screening plane (21).

[0270] The first guide unit (7), preferably, which can more preferably be a guide chain, can comprise second engaging elements, arranged at the screening plane (21) and engageable to the third edge (6) of the screen cloth (5), wherein the second engaging elements comprise a first seat (43): which extends in a longitudinal direction; and which has a first access aperture (46) (see figures 29, 36, 38-40 42 and 43), which extends in a longitudinal direction, which is positionable (and is preferably positioned) along the screening plane (21) and has a first width, measured perpendicularly to the screening plane (21). In this case, the third edge (6) of the screen cloth (5) is housable in the first seat (43) of the second engaging elements and comprises a first plurality of projecting retaining elements, wherein each projecting retaining element (44, 45) of the first plurality of projecting retaining elements has a fifth thickness, measured perpendicularly to the screening plane (21), that is greater than the first width so as to prevent the third edge (6) of the screen cloth (5) from exiting from the first seat (43) of the second engaging elements through the first access aperture (46) of the first seat (43) of the second engaging elements.

[0271] Particularly preferable is an embodiment of the screening apparatus (1) (see figures 36 and 40) wherein tthe second guide unit (37) comprises third engaging elements arranged at the screening plane (21) and engageable with the fourth edge (8) of the screen cloth (5), wherein the third engaging elements comprise (and preferably are) a second seat (343): which extends in a longitudinal direction; and which has a second access aperture (346), which extends in a longitudinal direction, which is positionable (and is preferably positioned) along the screening plane (21) and has a second width, measured perpendicularly to the screening plane (21); and wherein the fourth edge (8) of the screen cloth (5) is housable in the second seat (343) of the third engaging elements and comprises a second plurality of projecting retaining elements, wherein each projecting fixing element (44, 45) of the second plurality of projecting retaining elements has a sixth thickness, measured perpendicularly to the screening plane (21), which is greater than the second width so as to prevent the fourth edge (8) of the screen cloth (5) from exiting from the second seat (343) of the third engaging elements through the second access aperture (346) from the second seat (343) of the third engaging elements.

[0272] It is therefore further preferable for each projecting fixing element (44, 45) of the first plurality of projecting retaining elements, and, when present (and, preferably it is), of the second plurality of the pluralities of projecting retaining elements of the screen cloth (5) to be a tooth (45) of a zipper (or “zip closure”), since this simplifies the production of the screen cloth (5) and enables easy wrapping thereof about the winding roller (4).

[0273] Advantageously, the first access aperture (46) of the first seat (43) of the second engaging elements and, when present, the second access aperture (346) of the third engaging elements (343) is arranged symmetrically with respect to the screening plane (21), as, in that case, there is a more efficient engagement. Further, each projecting fixing element (44, 45) of the first, or, when present, of the plurality of projecting retaining elements, projects symmetrically from the two sides of the screen cloth (5). The projecting retaining elements (44, 45) can be advantageously constituted by press-studs (44) (enabling the creation of a stud retainer), or by teeth (45) of a zipper (enabling the zip retainer) but can also be constituted by other types of projecting retaining elements (44, 45).

[0274] With the aim of ensuring a correct positioning of the screen cloth (5), according to an embodiment of the invention, when third engaging elements are present, the screening apparatus (1) of the invention can preferably comprise regulating elements (not illustrated) for supporting the second seat (343) of the third engaging elements with the possibility of regulating the distance of the second access aperture (346) of the second seat (343) of the third engaging elements from the fourth edge (8) of the screen cloth (5) housed in the second seat (343) of the third engaging elements. The regulating elements can advantageously be housed in the second housing (42).

[0275] As the thickness of the teeth (45) is smaller with respect to other types of projecting retaining elements of the first and second plurality of pluralities of projecting retaining elements, it is necessary that, in the presence of the teeth (45), the first access aperture (46) of the second engaging elements and the second access aperture (346) of the third engaging elements is made with a minimal tolerance of measurement. For this purpose, an embodiment of the invention is preferred (see figures 40-43) in which the first guide unit (7) is a first guide chain (7) comprising a plurality of first guide chain elements, wherein each of the first chain elements of the plurality of first guide chain elements comprises:

[0276] - a bottom wall (50);

[0277] - a first external lateral wall (51) and a second external lateral wall (52), which originate from opposite sides of the bottom wall (50) (and which are preferably parallel to one another);

[0278] - a first internal wall (53) and a second internal wall (54), which are arranged between the first external lateral wall (51) and the second external lateral wall (52), which originate from the bottom wall (50), and which are positionable parallel to the screening plane (21), which are separated from the first external lateral wall (51) and from the second external lateral wall (52) (and preferably parallel thereto);

[0279] - a first retaining wall (55), which originates distally from the first internal wall (53), which is projecting from the first internal wall (53); and which is facing towards the second internal wall (54); and

[0280] - a second retaining wall (56), which originates distally from the second internal wall (54); which is projecting from the second internal wall (54), and which is facing towards the first internal wall (53); wherein the first internal wall (53), the second internal wall (54), the first retaining wall (55) and the second retaining wall (56) together define a section of the first seat (43) of the first engaging elements and wherein the first retaining wall (55) and the second retaining wall (56) together define a section of the first access aperture (46) of the first seat (43) of the first engaging elements and the second engaging elements. Obviously these sections are understood to be transversal with respect to the screening plane (21).

[0281] The fact that the first internal wall (53) and the second internal wall (54) are separated from the first external lateral wall (51) and from the second external lateral wall (52) enables greater dimensional control of the first access aperture (46) of the first seat (43) of the second engaging elements which is to retain the teeth (45) of the fourth edge (8) of the screen cloth (5), in particular when each of the first chain elements of the plurality of first chain elements are obtained by injection moulding in which there are always small deformations during the cooling step following the moulding. In order to guarantee that the second access aperture (346) of the second seat (343) of the third engaging elements is made with a minimum tolerance, when the second guide unit (37) and the third engaging elements are present, the second guide unit (37) preferably comprises (and is preferably constituted by):

[0282] - a profiled element (see figure 40): which extends in a longitudinal direction and which comprises: a body (57), which has an open ring transversal section; which internally defines the second seat (343) of the third engaging elements; which comprises the second access aperture (346) of the second seat (343) of the third engaging elements; wherein the profiled element further comprises a first longitudinal wing (58) and a second longitudinal wing (59), which are solidly constrained to the body (57) of the profiled element and arranged on opposite sides with respect to the second access aperture (346) of the second seat (343) of the third engaging elements;

[0283] - a support element (60) which extends in a longitudinal direction; which is positionable horizontally at the second side (62) of the opening in order to support the profiled element horizontally with the second access aperture (346) of the second seat (343) of the third engaging elements facing downwards at the screening plane (21) inferiorly abutting the first longitudinal wing (58) and the second longitudinal wing (59) of the profiled element. In this case, the screening apparatus (1) of the invention can preferably comprise regulating elements (not illustrated) for supporting the second seat (343) of the third engaging elements with the possibility of regulating the distance of the second access aperture (346) of the second seat (343) of the third engaging elements from the fourth edge (8) of the screen cloth (5) housed in the second seat (343) of the third engaging elements. The regulating elements can advantageously be housed in the second housing (42).

[0284] According to a preferred aspect of the invention, the first guide unit (7) can comprise fourth engaging elements, arranged at the screening plane (21) and engageable to the third edge (6) of the screen cloth (5) and wherein, when present, the second guide unit (37) comprises fifth engaging elements, arranged at the screening plane (21) and engageable with the fourth edge (8) of the screen cloth (5), wherein the fourth engaging elements (47), and, when present, the fifth engaging elements, comprise (and preferably are) a pair of third brushes (47, 347) (see figures 33-35) positionable (and preferably positioned) substantially symmetrically, with respect to the screening plane (21), with the relative bristles being: facing towards the screening plane (21); and terminating thereat. In this case, the screen cloth (5) comprises a fabric the weft of which is engageable with the bristles.

[0285] The bristles of the pair of third brushes (47) of the first guide unit (7) are preferably arranged inclined downwards, and the bristles of the pair of third brushes (347) of the second guide unit (37) are arranged inclinate upwards (figures 21-23) as in this way the weft of the screen cloth (5) is more effectively engaged.

[0286] In a preferred aspect of the invention, the second guide unit (37) can, alternatively to the third engaging elements and the fifth engaging elements, advantageously comprise sixth engaging elements (see figures 99-102), which comprise, in turn, a third seat (443), which extends in a longitudinal direction and which has a third access aperture (446), which extends in a longitudinal direction, which is positionable (and is preferably positioned) horizontally along the screening plane (21) and has a third width, measured perpendicularly to the screening plane (21); wherein the sixth engaging elements further comprise a cantilever element (445), which extends in a longitudinal direction, which is arranged in the third seat (443) of the sixth engaging elements, which has a first end (450), which is fixable (and, preferably, fixed) to the frame, in proximity of the upper part of the third side (61) of the opening, or is fixable (and, preferably, fixed) to the upper part of the third side (61) of the opening; which has a second free end (449) opposite the first end (450); and has a seventh thickness measured perpendicularly to the screening plane (21), that is greater than the third width; and wherein the fourth edge (8) of the screen cloth (5) comprises a hem (448) in turn comprising an annular opening (447) (see figure 99) arranged in proximity or at, the second edge (9) of the screen cloth (5) in which the cantilever element (445) is insertable (and preferably, inserted), via the second free end (449) thereof. This is to prevent the fourth edge (8) of the screen cloth (5), in which the cantilever element (445) is inserted (through the annular opening (447) of the hem (448)), from exiting from the third seat (443) of the sixth engaging elements through the third access aperture (446) of the third seat (443) of the sixth engaging elements.

[0287] In this case it is preferable for the screening apparatus (1) of the invention to comprise regulating elements (not illustrated) for supporting the third seat (443) of the sixth engaging elements with the possibility of regulating the distance of the third access aperture (446) of the third seat (443) of the sixth engaging elements from the fourth edge (8) of the screen cloth (5) housed in the third seat (443) of the sixth engaging elements. The regulating elements can advantageously be housed in the second housing (42).

[0288] The hem (448) can advantageously be made by sewing, welding (in the case of plastic material) or by the fixing of a flexible tubular element which extends in a longitudinal direction and can be rolled.

[0289] The third access aperture (346) of the third seat (443) of the third engaging elements is advantageously arranged symmetrically, with respect to the screening plane (21), as, in that case, there is a more efficient engagement.

[0290] The preferred screening apparatuses (1) according to the invention, is when the screen cloth (5) is selected from a group constituted by: a screen cloth (5) for screening against insects, a screen cloth (5) for at least partially screening the light; a waterproof screen cloth (5), a cloth for curtains, a cloth for awnings, a screen cloth (5) that is waterproof and at least partially transparent to visible light.

[0291] The first guide unit (7) and the relative first, second, fourth, fifth and sixth engaging elements, the compensating unit (10), the second guide unit (37), and the third, fourth and sixth engaging elements and the second housing (42) can have a relative extension, measured parallel to the first screening plane (21) which is at least equal to or greater than the extension of the screening portion of the cloth, measured parallel to the first screening plane (21).

[0292] It is understood that the above has been described by way of non-limiting example and that any constructional variants are considered to fall within the protective scope of the present technical solution, as claimed in the following.

Claims

CLAIMS1. A screening apparatus (1) for screening an opening, which opening is rectangular and comprises a first side (3) which is vertical, wherein:- it comprises a frame;- it comprises a first housing (2) which is part of the frame and which is vertically positionable at the first side (3) of the opening;- it comprises a winding roller (4) which is housable vertically in the first housing (2) so as to rotate with respect to the axis thereof;- it comprises a screen cloth (5) which comprises: a first edge which is fixed to the winding roller (4) so that the screen cloth (5) can be wound on, and be unwound from, the winding roller (4); a second edge opposite the first edge; a third edge (6) which is interposed between the first edge and the second edge;- it comprises a first guide unit (7), preferably a guide chain, for inferiorly guiding the screen cloth (5), which first guide unit: is couplable to the third edge (6) of the screen cloth (5); extends in a longitudinal direction; which first guide unit comprises a first end (38), which is fixable to the frame in proximity of the lower part of the first side (3) of the opening or at the lower part of the first side (3) of the opening; comprises a second end (39) opposite the first end (38); and can flex along the extension thereof so as to form at least a straight section and at least a curved section;- it comprises a sliding bar (11) which: is fixable to the second edge of the screen cloth (5); comprises a first end portion (12) and a second end portion (13), which is opposite the first end portion (12); comprises a first guide channel (16) for guiding at least a variable part of the first guide unit (7) which is decoupled from the third edge (6) of the screen cloth (5); the first guide channel (16): originates at the first end portion (12) of the sliding bar (11), extends in the sliding bar (11) and comprises: a first guide portion (25), which originates at the first end portion (12) of the sliding bar (11) and which is at least partially curved; a second guide portion (26) which originates from the first guide portion (25) of the first guide channel (16), which is straight and whichextends towards the second end portion (13) of the sliding bar (11); is characterised in that: the first guide channel (16) further comprises: a third guide portion (27), which originates from the second guide portion (26) of the first guide channel (16), which is arranged in the second end portion (13) of the sliding bar (11) and which is curved; a fourth guide portion (28), which originates from the third guide portion (27) of the first guide channel (16), which is straight and which extends towards the first end portion (12) of the sliding bar (11); the first guide channel (16) is configured for slidably receiving and flexing the variable part of the first guide unit (7) during a first activation of the sliding bar (11) along a screening plane (21) aimed at reducing the screening of the opening, in such a way that the second end (39) of the first guide unit (7) can slide in succession into the first guide portion (25) of the first guide channel (16), the second guide portion (26) of the first guide channel (16), the third guide portion (27) of the first guide channel (16) and the fourth guide portion (28) of the first guide channel (16).

2. The screening apparatus (1) of the preceding claim, further comprising a compensating unit (10), preferably a compensating chain or a compensating belt: which extends in a longitudinal direction; which comprises a first end (40), which is fixable to the frame in proximity of the upper part of the first side (3) of the opening or at the upper part of the first side (3) of the opening; which comprises a second end (41) opposite the first end (40); which can flex along the extension thereof to form: at least a straight section and at least a curved section; wherein the sliding bar (11) further comprises a second guide channel (17) for guiding at least a variable part of the compensating unit (10); wherein the second guide channel (17): originates at the second end portion (13) of the sliding bar (11), extends in the sliding bar (11) and comprises: a first guide portion (29), which originates at the second end portion (13) of the sliding bar (11) and which is at least partially curved; a second guide portion (30) which originates from the first guide portion (29) of the second guide channel (17), which is straight and which extends towards the first end portion (12) of the sliding bar (11); a thirdguide portion (31), which originates from the second guide portion (30) of the second guide channel (17), which is arranged in the first end portion (12) of the sliding bar (11) and which is curved; a fourth guide portion (32), which originates from the third guide portion (31) of the second guide channel (17), which is straight and which extends towards the second end portion (13) of the sliding bar (11); wherein the second guide channel (17) is configured for slidably receiving and flexing the variable part of the compensating unit (10, 24) during the first activation of the sliding bar (11) along a screening plane (21) aimed at reducing the screening of the opening, in such a way that the second end (41) of the compensating unit (10) can slide in succession into the first guide portion (29) of the second guide channel (17), the second guide portion (30) of the second guide channel (17), the third guide portion (31) of the second guide channel (17) and the fourth guide portion (32) of the second guide channel (17); wherein, when the first housing (2) is positioned vertically at the first side (3) of the opening with the winding roller (4) housed thereat and with the sliding bar (11) and which is vertical and which is fixed to the second edge of the screen cloth (5), the first guide channel (16) and the second guide channel (17) are entirely arranged on opposite sides with respect to a vertical plane (23) passing through the sliding bar (11) and parallel to the screening plane (21); wherein the screening apparatus (1) further comprises a synchronising unit for synchronising the sliding of the variable part of the first guide unit (7) in the first guide channel (16) and of the variable part of the compensating unit (10, 24) in the second guide channel (17); wherein the synchronising unit is connectable to the first guide unit (7) and to the compensating unit (10); and wherein the compensating unit (10, 24) and the synchronising unit are configured in such a way as, in use, to maintain the sliding bar (11) vertically orientated during a second activation of the sliding bar (11) along the screening plane (21) and aimed at increasing or reducing the screening of the opening.

3. The screening apparatus (1) of the preceding claim, wherein the synchronisingunit comprises:- a first plurality of synchronising channels, in turn comprising:- a first synchronising channel (78): which is arranged in the first end portion (12) of the sliding bar (11) and which conjoins the second guide portion (26) of the first guide channel (16) and the fourth guide portion (28) of the first guide channel (16) to one another,- a second synchronising channel (79): which is arranged in the second end portion (13) of the sliding bar (11); which conjoins the second guide portion (30) of the second guide channel (17) and the fourth guide portion (32) of the second guide channel (17) to one another;- a third synchronising channel (80): which is arranged in the first end portion (12) of the sliding bar (11); and which conjoins the second guide portion (26) of the first guide channel (16) and the fourth guide portion (32) of the second guide channel (17) to one another; and- a fourth synchronising channel (81): which is arranged in the second end portion (13) of the sliding bar (11); and which conjoins the fourth guide portion (28) of the first guide channel (16) and the second guide portion (30) of the second guide channel (17) to one another;- a first cable (380): which is insertable in the first plurality of synchronising channels, in the first guide channel (16) and in the second guide channel (17); which can flex along the extension thereof to form at least a straight section and at least a curved section; which comprises a first end, which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which comprises a second end, which is opposite the first end of the first cable (380), which is fixed to the second end (41) of the compensating unit (10, 24) arranged in the second guide channel (17);- a second cable (381): which is insertable in the first plurality of synchronising channels, in the first guide channel (16) and in the second guide channel (17); which can flex along the extension thereof to form: at least a straight section and at least a curved section; which comprises a first end, which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); whichcomprises a second end, which is opposite the first end of the second cable (381), which is fixed to the second end (41) of the compensating unit (10, 24) arranged in the second guide channel (17).

4. The screening apparatus (1) of the preceding claim, wherein the first cable (380), in a minimum screening configuration of the screening apparatus (1), comprises:- a first portion (82), which comprises the first end of the first cable (380); and which is arranged in the fourth guide portion (28) of the first guide channel (16);- a second portion (83): which originates from the first portion (82) of the first cable (380); and which is arranged in the first synchronising channel (78);- a third portion (84): which originates from the second portion (83) of the first cable (380); and which is arranged in the second guide portion (26) of the first guide channel (16) and in the third guide portion (27) of the first guide channel(16);- a fourth portion (85): which originates from the third portion (84) of the first cable (380); and which is arranged in the fourth synchronising channel (81);- a fifth portion (86): which originates from the fourth portion (84) of the first cable (380); which is arranged in the second guide portion (30) of the second guide channel (17), in the third guide portion (31) of the second guide channel (17) and in the fourth guide portion (32) of the second guide channel (17); and which comprises the second end of the first cable (380); and wherein the second cable (381), in the minimum screening configuration of the screening apparatus (1), comprises:- a first portion (87): which comprises the second end of the second cable (381); and which is arranged in the fourth guide portion (32) of the second guide channel(17);- a second portion (88): which originates from the first portion (87) of the second cable (381); and which is arranged in the second synchronising channel (79);- a third portion (89): which originates from the second portion (88) of the secondcable (381); and which is arranged in the second guide portion (30) of the second guide channel (17) and in the third guide portion (31) of the second guide channel (17);- a fourth portion (90): which originates from the third portion (89) of the second cable (381); and which is arranged in the third synchronising channel (80);- a fifth portion (91): which originates from the fourth portion (90) of the second cable (381); which is arranged in the second guide portion (26) of the first guide channel (16), in the third guide portion (27) of the first guide channel (16) and in the fourth portion of the first guide channel (16); and which comprises the first end of the second cable (381).

5. The screening apparatus (1) of claim 2, wherein the synchronising unit comprises a second plurality of synchronising channels, in turn comprising:- a fifth synchronising channel: which is arranged in the first end portion (12) of the sliding bar (11) and which conjoins the second guide portion (26) of the first guide channel (16) and the fourth guide portion (28) of the first guide channel (16) to one another;- a sixth synchronising channel: which is arranged in the second end portion (13) of the sliding bar (11) and which conjoins the second guide portion (30) of the second guide channel (17) and the fourth guide portion (32) of the second guide channel (17) to one another;- a third cable (95): which is insertable in the second plurality of synchronising channels, in the first guide channel (16) and in the second guide channel (17); which can flex along the extension thereof to form at least a straight section and at least a curved section; which comprises a first end which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which comprises a second end, which is opposite the first end of the third cable (95) and fixed to the second end (41) of the compensating unit (10, 24) arranged in the second guide channel (17);- a first upper direction inversion element (94) which: which is arranged in the second end portion (13) of the sliding bar (11); which windingly receives the third cable (95); which js arranged and dimensioned in such a way that the third cable(95) can be arranged in the second guide portion (26) of the first guide channel (16), can wind about the first upper direction inversion element (94) and can be arranged in the second guide portion (30) of the second guide channel (17);- a fourth cable (96): which is insertable in the second plurality of synchronising channels, in the first guide channel (16) and in the second guide channel (17); which can flex along the extension thereof to form at least a straight section and at least a curved section; which comprises a first end which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which comprises a second end, which is opposite the first end of the fourth cable (96) and fixed to the second end (41) of the compensating unit (10, 24) arranged in the second guide channel (17);- a first lower direction inversion element (93) : which is arranged in the first end portion (12) of the sliding bar (11); which windingly receives the fourth cable (96); which is arranged and dimensioned in such a way that the fourth cable (96) can be arranged in the second guide portion (30) of the second guide channel (17), can wind about the first lower direction inversion element (93) and can be arranged in the second guide portion (26) of the first guide channel (16).

6. The screening apparatus (1) of the preceding claim, wherein the third cable (95), in a minimum screening configuration of the screening apparatus (1), comprises:- a first portion (97): which comprises the first end of the third cable (95); and which is arranged in the fourth guide portion (28) of the first guide channel (16);- a second portion (98): which originates from the first portion (97) of the third cable (95); and which is arranged in the fifth synchronising channel;- a third portion (99): which originates from the second portion (98) of the third cable (95); which is arranged in the second guide portion (26) of the first guide channel (16);- a fourth portion (201): which originates from the third portion (99) of the third cable (95); and which winds about the first upper direction inversion element (94);- a fifth portion (202): which originates from the fourth portion (201) of the thirdcable (95); which is arranged in the second guide portion (30) of the second guide channel (17), in the third guide portion (31) of the second guide channel (17) and in the fourth guide portion (32) of the second guide channel (17); and which comprises the second end of the third cable (95); and wherein the fourth cable (96), in the minimum screening configuration of the screening apparatus (1), comprises:- a first portion (203), which comprises the second end of the fourth cable (96); and which is arranged in the fourth guide portion (32) of the second guide channel (17);- a second portion (204): which originates from the first portion (203) of the fourth cable (96); and which is arranged in the sixth synchronising channel;- a third portion (205): which originates from the second portion (204) of the fourth cable (96); and which is arranged in the second guide portion (30) of the second guide channel (17);- a fourth portion (206): which originates from the third portion (205) of the fourth cable (96); and which winds about the first lower direction inversion element (93);- a fifth portion (207); which originates from the fourth portion (206) of the fourth cable (96); which is arranged in the second guide portion (26) of the first guide channel (16), in the third guide portion (27) of the first guide channel (16) and in the fourth guide portion (28) of the first guide channel (16); and which comprises the first end of the fourth cable (96).

7. The screening apparatus (1) of any one of claims 2-5, further comprising a second housing (42), which is part of the frame, and which is horizontally positionable at a second side (62) of the opening, which originates from the upper part of the first side (3) of the opening; wherein, in the second housing (42), when positioned horizontally, the following are contemporaneously housable: at least partially, the compensating unit (10), positioned horizontally; and the second end portion (13) of the sliding bar (11), with freedom to slide relatively between the second end portion (13) of the sliding bar (11 ) and the second housing (42).

8. The screening apparatus (1) of the preceding claim, comprising at least a firstbrush (48): which extends in a longitudinal direction; which is arranged horizontally in the second housing (42); which comprises bristles that are configured and arranged to inferiorly support the compensating unit (10, 24) housed in the second housing (42), wherein the at least a first brush (48) is arranged in one of following positions: on a first longitudinal side of the compensating unit (10, 24) housed in the second housing (42); on a second longitudinal side of the compensating unit (10, 24) housed in the second housing (42), which is opposite the first longitudinal side; or when the at least a first brush (48) is a pair of first brushes (48), on both the first and the second longitudinal side of the compensating unit (10).

9. The screening apparatus (1) of claim 1 , comprising a first partial compensating unit, in turn comprising:- a second lower direction inversion element (208) which is arranged in the first end portion (12) of the sliding bar (11);- a second upper direction inversion element (209) which is arranged in the second end portion (13) of the sliding bar (11 );- a fifth cable (210): which has a first end which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which has a second end opposite the first end, and which is fixable to the frame in proximity of the upper part of a third side (61) of the opening opposite the first side (3) of the opening or which is fixable to the upper part of the third side (61) of the opening; and which is arranged in such a way that, starting from the relative second end, winds about the second upper direction inversion element (209), winds about the second lower direction inversion element (208) and enters the first guide channel (16).

10. The screening apparatus (1) of claim 1 or 9, comprising a second partial compensating unit, in turn comprising:- a third lower direction inversion element (213) arranged in the first end portion (12) in the sliding bar (11);- a third upper direction inversion element (214), arranged in the second end portion (13) of the sliding bar (11) above the a third lower direction inversionelement (213);- a sixth cable (215): which has a first end which is fixed to the second end (39) of the first guide unit (7) arranged in the first guide channel (16); which has a second end opposite the first end, and which is fixable to the frame in proximity of the upper part of the first side (3) of the opening or which is fixable to the upper part of the first side (3) of the opening; and which is arranged in such a way that, starting from the relative second end, winds about the third upper direction inversion element (214), winds about the third lower direction inversion element (213) and enters the first guide channel (16).

11. The screening apparatus (1) of any one preceding claim, wherein the first guide unit (7) is a first guide chain (7) comprising a first plurality of guide chain elements, wherein each of the guide chain elements (221 , 248, 249, 250) of the first plurality of guide chain elements is hingeable at a first hinge axis (222) and at a second hinge axis (223), parallel to one another, and comprises:- a bottom (228) positionable resting on a horizontal support plane; wherein the first hinge axis (222) and the second hinge axis (223) are arranged at a first height from the support plane;- first engaging elements (226) for coupling to the third edge (6) of the screen cloth (5) and along a coupling direction which is perpendicular to the first hinge axis (222); wherein the first engaging elements (226) are arranged on an opposite side to the bottom (228) at a second height from the support plane which is lower than the first height;- a first longitudinal wall (224): arranged perpendicular to the bottom (228) and to the first hinge axis (222); which comprises a first portion (225) having a first thickness and a second portion (227) having a second thickness which is smaller than the first thickness, wherein the first portion (225) of the first longitudinal wall (224): it comprises: a first tapered projecting region (229), which has a first convex edge (230) and which projects with respect to a first side of the first engaging elements (226) which is parallel to the first hinge axis (222), which comprises a first chain element (331) arranged at the first hinge axis (222); and wherein the first portion (225) of the first longitudinal wall (224) further comprises a first concave edge (232) opposite the first convex edge (230) and complementarilyprofiled with respect to the first convex edge (230), wherein the second portion (227) of the first longitudinal wall (224) originates from the first concave edge(232) of the first portion (225) of the first longitudinal wall (224) and comprises a second chain element (240) arranged at the second hinge axis (223);- a second longitudinal wall (233) opposite the first longitudinal wall (224) which comprises: a first portion (234) having a third thickness; a second portion (235) having a fourth thickness which is smaller than the third thickness; a third portion (236) having the third thickness and a fourth portion (237) having the fourth thickness; wherein the first portion (234) of the second longitudinal wall (233) has a second tapered projecting region (238); which has a second convex edge (239); which projects with respect to the first side of the first engaging elements (226); which comprises a third chain element (241) arranged at the first hinge axis (222); and wherein the first portion (234) of the second longitudinal wall (233) further comprises a second concave edge (244) opposite the second convex edge (239) and complementarily profiled with respect to the second convex edge (239), wherein the second portion (235) of the second longitudinal wall (233) originates from the second concave edge (244) and comprises a fourth chain element (242) arranged at the second hinge axis (223); wherein the third portion (236) of the second longitudinal wall (233) is arranged inferiorly of the second portion (235) of the second longitudinal wall (233) and has a third tapered projecting region (245), which has a third convex edge (246), which projects with respect to a second side of the first engaging elements (226) opposite the first side of the first engaging elements (226); wherein the third portion (236) of the second longitudinal wall(233) further comprises a third concave edge (247) opposite the third convex edge (246) and complementarily profiled with respect to the third convex edge (246), wherein the fourth portion (237) of the second longitudinal wall (233) originates from the third concave edge (247) and is arranged inferiorly of the first portion(234) of the second longitudinal wall (233); wherein the first chain element (331) and the third chain element (241) of a first guide chain element (248) of the first plurality of guide chain elements are hinged, respectively, to the second chain element (240) and to the fourth chain element (242) of a second guide chain element (249) of the first plurality of guide chain elements which, in the first guide chain (7), follows the first guide chain element(248), and wherein the second chain element (240) and the fourth chain element (242) of the first guide chain element (248) are hinged, respectively, to the first chain element (331) and to the third chain element (241) of a third guide chain element (250) of the first plurality of guide chain elements which, in the first guide chain (7), precedes the first guide chain element (248) in the first guide chain (7), so that when the first guide chain (7) is flexed along the extension thereof forming a straight section and at least a curved section, in the straight section: the first convex edge (230) and the second convex edge (239) of the first guide chain element (248) contact, respectively, the first concave edge (232), and the second concave edge (244) of the second guide chain element (249) and the third convex edge (246) of the first guide chain element (248) contact the third concave edge(247) of the third guide chain element (250); while, in the curved section, the first convex edge (230) and the second convex edge (239) of a further first guide chain element (248) are separated, respectively from the first concave edge (232) and the second concave edge (244) of a further second guide chain element (249) of the first plurality of guide chain elements which, in the first guide chain (7), follows the further first guide chain element (248), and the third convex edge (246) of the first guide chain element (248) is separated from the third concave edge (247) of a further third guide chain element (250) of the first plurality of guide chain elements which, in the first guide chain (7), precedes the further first guide chain element(248).

12. The screening apparatus (1) of any one claim from 2 to 8 or claim 11 , wherein the compensating unit (10, 24) is a first compensating chain (10) comprising a plurality of compensating chain elements wherein each of the compensating chain elements (253, 262, 263, 264) of the plurality of compensating chain elements is hingeable to a third hinge axis (256) and a fourth hinge axis (257), parallel to one another, and comprises:- a body (258) comprising; a fifth chain element (255) passing through the third hinge axis (256); a first transversal side of the body (258) perpendicular to the third hinge axis (256); a second transversal side of the body (258) opposite the first transversal side of the body (258),- an undercut (259) accessible from the first transversal side of the body (258); and- a protuberance (265) which projects from the second transversal side of the body (258), which is housable in the undercut (259) of the body (258) of a further compensating chain element (253) of the plurality of compensating chain elements, and which comprises: a fourth convex edge (270); and a sixth chain element (271); wherein the fifth chain element (255) of a first compensating chain element (262) of the plurality of compensating chain elements is hinged to the sixth chain element (271) of a second compensating chain element (263) of the plurality of compensating chain elements which follows it in the first compensating chain, and the sixth chain element (271) of the first compensating chain element (262) is hinged to the fifth chain element (255) of a third compensating chain element (264) of the plurality of compensating chain elements which precedes it in the first compensating chain (10), so that when the first compensating chain (10) is flexed along the extension thereof forming a straight section and at least a curved section, in the straight section: the protuberance (265) of the first compensating chain element (262) is entirely housed in the undercut (259) of the body (258) of the third compensating chain element (264) with the first transversal side of the body (258) of the third compensating chain element (264) contacting the second transversal side of the body (258) of the first compensating chain element (262); and the protuberance (265) of the second compensating chain element (263) is entirely housed in the undercut (259) of the body (258) of the first compensating chain element (262), with the second transversal side of the body (258) of the second compensating chain element (263) contacting the first side of the body (258) of the first compensating chain element (262); and wherein in the curved section:- the protuberance (265) of a further second compensating chain element (263) of the plurality of compensating chain elements that follows, in the first compensating chain (10), a further first compensating chain element (262) of the plurality of compensating chain elements is partially housed in the undercut (259) of the body (258) of the further first compensating chain element (262) with the second side ofthe body (258) of the further second compensating chain element (263) being separated from the first transversal side of the body (258) of the further first compensating chain element (262); and- the protuberance (265) of the further first compensating chain element (262) of the plurality of compensating chain elements is partially housed in the undercut (259) of the body (258) of a further third compensating chain element (264) of the plurality of compensating chain elements which precedes it in the first compensating chain, with the first transversal side of the body (258) of the further third compensating chain element (264) being separated from the second transversal side of the body (258) of the further first compensating chain element (262).

13. The screening apparatus (1) of any one of claims 6-8 and 11-12, wherein the compensating unit (10, 24) is a second compensating chain (10) comprising a second plurality of compensating chain elements, wherein each of the compensating chain elements (253) of the second plurality of compensating chain elements is hingeable at a fifth hinge axis (256) and at a sixth hinge axis (257), parallel to one another, and comprises at least a first through-hole (280), which is parallel to the fifth hinge axis (256) which is accessible in a straight section of the second compensating chain; wherein the second housing (42) comprises at least a second brush (49): which extends in a longitudinal direction; which is arranged horizontally; which is arranged in the second housing (42) parallel to the screening plane (21); which comprises bristles which are configured and arranged to support the second compensating chain (10) by inserting in the first through-hole (280) of each of the compensating chain elements (253, 262, 263, 264) of the plurality of compensating chain elements of the second compensating chain (10) housed in the second housing (42), wherein the at least a second brush (49) is arranged in one of following positions: on the first side of the second compensating chain (10) housed in the second housing (42); on the second side of the second compensating chain (10) housed in the second housing (42) opposite the first side; or when the at least a second brush (49) is a pair of second brushes, on both the first and the second side of the second compensating chain (10) housed in the second housing (42).

14. The screening apparatus (1) of any one preceding claim, wherein: the screencloth (5) comprises a fourth edge (8), opposite the third edge (6), wherein the screening apparatus (1) further comprises:- a second guide unit (37), for superiorly guiding the screen cloth, which second guide unit (37): is couplable to a fourth edge (8) of the screen cloth (5), which is opposite the third edge (6) of the screen cloth (5); extends in a longitudinal direction; comprises a first end; comprises a second end opposite the first end; is horizontally positionable at the second side (62) of the opening, laterally to the compensating unit (10), with the first end of the second guide unit (37) being fixed to the frame, in proximity of the upper part of the first side (3) of the opening or fixed at the upper part of the first side (3) of the opening, and with the second end of the second guide unit (37) being fixed to the frame, in proximity of the upper part of the third side (31) of the opening, in proximity of the upper part of the third side (61) of the opening or fixed to the upper part of the third side (61) of the opening; and- optionally, the second housing (42), wherein, in the second housing (42), when present and positioned horizontally, the second guide unit (37) is further contemporaneously housable, positioned horizontally and laterally to the compensating unit (10).

15. The screening apparatus (1) of any one preceding claim, wherein the first guide unit (7) comprises second engaging elements, arranged at the screening plane (21) and engageable to the third edge (6) of the screen cloth (5), wherein the second engaging elements comprise a first seat (43): which extends in a longitudinal direction; and which has a first access aperture (46), which extends in a longitudinal direction, which is positionable along the screening plane (21) and has a first width, measured perpendicularly to the screening plane (21); and wherein the third edge (6) of the screen cloth (5) is housable in the first seat (43) of the second engaging elements and comprises a first plurality of projecting retaining elements, wherein each projecting fixing element (44, 45) of the first plurality of projecting retaining elements has a fifth thickness, measured perpendicularly to the screening plane (21), that is greater than the first width so as to prevent the third edge (6) of the screen cloth (5) from exiting from the first seat (43) of the second engaging elements through the first access aperture (46) of the first seat (43) of the second engaging elements.

16. The screening apparatus (1) of any one of claims 14-15, wherein the second guide unit (37) comprises third engaging elements arranged at the screening plane (21) and engageable with the fourth edge (8) of the screen cloth (5), wherein the third engaging elements comprise a second seat (343): which extends in a longitudinal direction; and which has a second access aperture (346), which extends in a longitudinal direction, which is positionable along the screening plane (21) and has a second width, measured perpendicularly to the screening plane (21); and wherein the fourth edge (8) of the screen cloth (5) is housable in the second seat (343) of the third engaging elements and comprises a second plurality of projecting retaining elements, wherein each projecting fixing element (44, 45) of the second plurality of projecting retaining elements has a sixth thickness, measured perpendicularly to the screening plane (21), which is greater than the second width so as to prevent the fourth edge (8) of the screen cloth (5) from exiting from the second seat (343) of the third engaging elements through the second access aperture (346) from the second seat (343) of the third engaging elements.

17. The screening apparatus (1) of any one of claims 15-16, wherein each projecting fixing element (44, 45) of the first plurality of projecting retaining elements, and, when present, of the second plurality of the pluralities of projecting retaining elements is a tooth (45) of a zipper.

18. The screening apparatus (1) of the preceding claim, wherein the first guide unit (7) is a second guide chain comprising a second plurality of guide chain elements, wherein each of the guide chain elements of the second plurality of guide chain elements comprises:- a bottom wall (50);- a first external lateral wall (51) and a second external lateral wall (52), which originate from opposite sides of the bottom wall (50);- a first internal wall (53) and a second internal wall (54), which are arranged between the first external lateral wall (51) and the second external lateral wall (52), which originate from the bottom wall (50), and which are positionable parallel to the screening plane (21), which are separated from the first external lateral wall (51) and from the second external lateral wall (52);- a first retaining wall (55), which originates distally from the first internal wall (53), which is projecting from the first internal wall (53); and which is facing towards the second internal wall (54); and- a second retaining wall (56), which originates distally from the second internal wall (54); which is projecting from the second internal wall (54), and which is facing towards the first internal wall (53); wherein the first internal wall (53), the second internal wall (54), the first retaining wall (55) and the second retaining wall (56) together define a section of the first seat (43) of the second engaging elements (43) and wherein the first retaining wall (55) and the second retaining wall (56) together define a section of the first access aperture (46) of the first seat (43) of the second engaging elements (43).

19. The screening apparatus (1) of any one of claims 1-8 and 11-14, wherein the first guide unit (7) comprises fourth engaging elements, arranged at the screening plane (21) and engageable to the third edge (6) of the screen cloth (5) and wherein, when present, the second guide unit (37) comprises fifth engaging elements, arranged at the screening plane (21) and engageable to the fourth edge (8) of the screen cloth (5), wherein the fourth engaging elements, and, when present, the fifth engaging elements, comprise a pair of third brushes (47, 347) positionable substantially symmetrically, with respect to the screening plane (21), with the relative bristles being: facing towards the screening plane (21); terminating thereat; and wherein the screen cloth (5) comprises a fabric the weft of which is engageable with the bristles.

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