EP0031039B1 - Tower shaped shielding for radio-engineering systems - Google Patents

Description

The invention relates to a tower-like cladding for protecting radio-technical systems, in particular antennas, against the weather, according to the preamble of claim 1.

Such a cladding is known from DE-B-1 2.73 023. In this known cladding, segments of rigid polyurethane foam are prefabricated in easily transportable sizes and connected at the construction site by gluing, so that individual, for example 12-segment, sleeve-shaped wefts are formed which, when stacked, can form the tower-like cladding, for example of antennas. When cladding long antenna masts, the self-supporting cladding, which is self-supporting in the manner described, is secured at the sides by structures arranged on the antenna mast, in particular in the area or in the form of the platforms of conventional radio antenna masts arranged one above the other.

Since antennas, in particular radio antennas, are known to be installed in exposed locations such as hills, mountains, buildings, such as television towers, etc., in order to achieve the greatest possible range, the antenna masts and their cladding are regularly exposed to considerable wind loads. These wind loads lead to corresponding pressure and suction loads when flowing around the panel, which seek to deform the panel. Furthermore, the wind loads often lead to very significant vibrations, in particular the long antenna mast and, due to the vibration excitation by eddy detachment at the periphery of the cladding and the structure supporting it, to natural vibrations, in particular of the antenna mast, the vibrations of which are in turn introduced into the cladding. As a result, the wall made of rigid foam of the cladding is subject to considerable, rapidly changing tensile and buckling stresses, which leads to considerable and disruptive noise. Last but not least, the changing and swelling permanent loads on the cladding lead to material fatigue and thus to failures.

In contrast, the invention has for its object to provide a cladding of the type outlined in the preamble of claim 1, the material of which is subjected to considerably lower loads, so that the service life is increased and, if necessary, noise can be reduced.

This object is achieved by the characterizing features of claim 1.

Because each shot is rigidly attached to one side of a supporting structure only, the introduction of tensions into the casing by relative movement of the supporting structures against one another is avoided. In the case of long antenna masts in particular, the axially movable bearing, preferably the upper edge of the weft, enables lateral oscillation deflections of the antenna mast without introducing significant tensile or buckling stresses into the material of the casing. As a result, the cladding does not produce any disturbing amounts of noise even in stormy weather, and the considerably reduced service life of the cladding results from the considerable reduction in mechanical material stress. The fact that the edge of at least the axially movable end of each shot is bordered by a border profile made of wear-resistant material such as glass-fiber reinforced unsaturated polyester, this edge can serve for a clean anchoring of a reinforcement without damaging the rigid foam, but with which an axially movable, but transversely to this, however immobile connection to the structure. As a result, the axially movable end of each shot is nevertheless secured in the transverse direction to the axis of the mast and can therefore not make any relative movements to the adjacent, rigidly attached edge of the adjacent shot transversely to the movement joint. In addition to relieving the rigidly attached end of the shot from bending moments, the result is that although the width of the expansion joint can vary under wind forces, for example, the edges of the expansion joint are always in alignment. This in turn creates the prerequisite for covering the movement joint at least on its outside by a masking tape, which consists of wear-resistant material such as glass fiber reinforced unsaturated polyester, so that no open gap appears in the region of the movement joint, through which z. B. driving rain could penetrate into the interior of the panel. The position of the edges of the movement joint in their direction of escape ensures a clean contact of the side edges of the masking tape on the outside of the edge areas of adjacent shots, without the masking tape having to follow relative changes in the position of its contact surfaces on the adjacent shots. Therefore, the masking tape can be made relatively stiff and strong for effective protection and is itself not exposed to any significant stresses that could lead to leaks and material fatigue. Overall, a tower-like cladding is thus created which is completely closed all around and functionally corresponds in its entirety to a generic cladding, but is free from excessive material stresses and in particular without noise.

The dependent claims contain advantageous developments of the invention.

• Fig. schematisch vereinfacht eine Übersichtsdarstellung eines mit einer erfindungsgemäßen Verkleidung versehenen Antennenmastes an der Spitze eines Fernsehturmes,
• Fig. 2 die Einzelheit gemäß Kreis II in Fig. 1 in vergrößerter Darstellung sowie im Axialschnitt,
• Fig. 3 einen Schnitt gemäß Linie III-III in Fig. 2 und
• Fig. eine abgewandelte Ausführungsform der Einzelheit gemäß Kreis II in Fig. 1.

Further details and advantages of the invention result from the following description of embodiments with reference to the Drawing. It shows

• 1 schematically simplified an overview of an antenna mast provided with a covering according to the invention at the top of a television tower,
• 2 shows the detail according to circle II in FIG. 1 in an enlarged view and in axial section,
• Fig. 3 shows a section along line III-III in Fig. 2 and
• FIG. 1 shows a modified embodiment of the detail according to circle II in FIG. 1.

In Fig. 1, 1 denotes a concrete tip of a television tower, on which an antenna mast 2 is placed, which carries a plurality of radio antennas, not shown, on its circumference in a manner known per se. In the example, in superimposed levels, nine supporting structures 3 designed as platforms are attached to the circumference of the antenna mast, the diameter of which gradually becomes smaller towards the top, and which serve as a carrier for a shell, denoted overall by 4, as a covering for the antenna mast 2. In the example, the mutual spacing of the platforms or supporting structures 3 may be approximately 4.8 m, with a height difference of over 40 m resulting between the upper edge of the concrete tip 1 of the television tower and an upper roof 5 of the casing 4. The diameter of the sheath 4 may drop from 4.6 m at the lower end to approximately 2.5 m in the area of the roof 5 with a base-side diameter of the antenna mast 2 of approximately 1.7 m. As can easily be seen from these exemplary dimensions, in particular in an exposed position, for example at the top of a television tower, considerable vibrations of the antenna mast 2 occur when there is a wind load, as well as significant natural vibrations of the elongated antenna mast 2 when resonating with vortex detachment frequencies, which in the case of a rigid attachment of the Shell 4 are transmitted as tensile and buckling stresses in the peripheral wall, which causes noise and leads to premature material fatigue.

The casing 4 consists of a plurality of shots 6 in the example case of the same height between the individual structures 3 and a shorter, shorter section 7 on the foot side and a shorter, shorter section 8 on the roof side. Each section 6, 7 or 8 is made in the manner known per se A plurality of, for example, twelve circumferential individual segments are assembled in a manner not shown in detail, the individual segments abutting one another at folded butt joints and glued to one another there at the construction site. The bottom shot 7 sits on the correspondingly formed upper edge of the concrete tip 1, while the overlying shots 6 and 8 are fastened with their undersides to the corresponding structures in the manner explained in more detail below, while the tops of the shots 6 and 7 in the direction the axis of the antenna mast 2 and the sheath 4, designated 9, are movably mounted.

The manner in which the upper and lower ends of the wefts 6 are supported is illustrated in more detail in FIG. 2, which corresponds to the detail according to circle 11 in FIG. 1 on an enlarged scale, while FIG. 3 shows a section along line III-III in FIG 2 corresponds.

As can be seen from FIGS. 2 and 3, the supporting structure 3 consists of an on-site platform or console 10 of any type, which can be a steel structure or can optionally also consist of concrete, as well as a supporting device 11 for the casing 4 attached to it. The support device 11 consists in the example of a plurality, preferably one of the number of individual segments for each shot 6 corresponding number of steel tabs 12, which are fixed in the manner shown in FIGS. 2 and 3 by massive bolts 13 on the top of the console 10 in such a way are that they protrude radially beyond the outer edge 10 'of the console 10. On each steel tab 12, a support tab 14 is welded, which is also made of steel and forms the lower support for the lower edge of the upper shot 6, designated 15. For this purpose, in the radial area of the lower edge 15 of the upper weft 6, an angle rail 16 following the shape of the lower edge 15 of the upper weft 6 is placed on the upper side of the carrying tab 14, on which the lower edge 15 of the upper edge is explained in a manner to be explained in more detail below Shot 6 is rigidly attached.

On the underside of the bracket 10, a further tab 17 is held by the screw bolts 13, which can be made of glass fiber reinforced plastic such as epoxy resin and also radially projects beyond the radial outer edge 10 'of the bracket 10. A base plate 19 is fastened to the underside of the tab 17 by means of screw bolts 18 and nuts 14 '. Between the upper bracket 14 and the lower base plate 19, a T-shaped stiffening structure 20, which can be seen in section in FIG. 3, is provided, which is welded to the bracket 14 and the base plate 19, so that a box-shaped housing results. In the area of the radially outer, open end of this housing, two guide bolts 21 are arranged vertically and parallel to one another between the upper support bracket 14 and the lower base plate 19 and fastened, for example, by welding.

The upper edge of the lower shot 6, designated 22, is provided with a reinforcement 23, which consists of an angle rail 24 adapted to the shape of the upper edge 22 of the lower shot 6 on the upper end face 25 of the shot 6 and of a bracket angle 26. The angle rail 24 is connected in the region of its leg 27 parallel to the end face 25 of the lower weft 6 by four screw bolts 28 to a parallel leg 29 of the bracket angle 26 in the example. The leg 30 of the angle rail 24 which is at an angle to the leg 27 is located on the inside of the upper edge 22 of the lower shot 6 and points downwards. The leg 30 serves to fix the angle rail 24 with respect to the upper edge 22 of the lower shot 6 by a number of screw bolts 31, which clamp the upper edge 22 of the lower shot 6 against the leg 30 of the angle rail 24. In this way, the reinforcement 23 is attached via the leg 30 of the angle rail 24 to the upper edge 22 of the lower shot 6.

As can also be seen from FIG. 3, in which only the reinforcement 23 is illustrated in this radial area for the sake of clarity, the second leg of the bracket bracket 26 is formed by two guide sleeves 32, which the guide bolts 21 with good interposition of bushings 33 Grip sliding properties, for example made of polyethylene. As can be easily seen from this, the upper edge 22 of the lower weft 6 with the reinforcement 23 attached to it is thereby held vertically movable in the direction of the guide bolts 21, but is laterally guided cleanly on the guide bolts 21. Thus, if the side of the supporting structure 3 illustrated in FIG. 2 rises or falls in accordance with the oscillation deflection of the antenna mast, the guide sleeves 32 can slide vertically on the guide pin 21 and there are no noticeable tensile or buckling forces in the wall of the shot 6 from the top thereof Edge 22 introduced here.

The angled rail 16 at the lower edge of the upper weft 6 is a mirror image of the angled rail 24 and with a horizontal leg 34 on the lower end face 35 of the upper weft 6, while the angled leg 36 rotates on the inside of the weft 6. As can be seen in particular from FIG. 3 with regard to the angle rail 24, the angle rails 16 and 24 run over at least a large part of the circumference of the lower edge 15 and the upper edge 22 of the respective weft 6, while the support bracket 14 and the bracket angle 26 only reach about the width of the steel plate 12. In a manner similar to the angle rail 24 on the upper edge 22, the angle rail 16 is fastened on the lower edge 15 of the associated weft 6 by means of screw bolts 37 which essentially horizontally penetrate the wall of the weft 6 made of rigid foam, in particular rigid polyurethane foam, and the lower edge 15 clamp against the leg 36 of the angle rail 16. Thus, the lower edge 15 of the upper weft 6 is rigidly fixed against the supporting structure 3, the connection between the angle rail 16 and the supporting bracket 14 being effected by means of bolts 38 similar to the bolts 28.

In order to enable relative movements between the reinforcement 23 and the guide pin 21 or the support structure 3, an expansion or movement joint 39 with a sufficiently large gap between the reinforcement 23 and the support bracket 14 is provided on the end faces 25 and 35 of the adjacent sections 6. An annular soft seal 40 is arranged in the movement joint 39, which is indicated in FIG. 2 only by dash-dotted outer contours for the sake of clarity. The soft seal 40 consists, for example, of closed-cell neoprene foam or a similar material, which has a compressibility of up to about 90 percent with a slight rise in back pressure, i.e. can be compressed to a tenth of its height without substantial tension build-up, so that the soft seal 40 changes the height of the gap Expansion joint 39 can follow.

The two axial ends in the region of the lower edge 15 and the upper edge 22 of each weft 6 are covered by border profiles 41 and 42, which can be made of a wear-resistant material such as glass fiber reinforced, unsaturated polyester. The side walls of the Einfaßprofile 41 and 42 are covered up to an area over the sides of the edges 15 and 22, which is outside the attack of any fastening or covering.

The area of each movement joint 39 between adjacent sections 6 is covered by a masking tape 43 on its outside. The cover band 43 running all the way around on the outside of the movement joint 39 is expediently clamped in its upper part by the screw bolts 37, which fix the lower edge 15 of the upper weft 6 against the associated angle rail 16, while its lower end engages over the head of the screw bolts 31, which fix the upper edge 22 of the lower shot 6 against the angle rail 24. In this way, the lower end of the cover band 43 is slidably held relative to the upper edge 22 of the lower weft 6 and can slide along the corresponding border profile 42. Conversely, of course, the fixing could also take place at the lower end of the cover band 43 and, for this purpose, its upper end slide on the border profile 41 for the lower edge 15 of the upper weft 6. As illustrated in Fig. 2, the adjacent side wall of the lower border profile 42 engages under the lower end of the cover band 43 to such an extent that relative movements can occur, so that with all occurring relative movements a clean flat contact of the lower end or edge of the cover band 43 is ensured on an adjacent surface of the border profile 43. For reasons of assembly technology, the masking tape 43 is likewise constructed from individual segments, similar to the wefts 6, which is not shown in more detail, the individual segments abutting one another with folded butt joints which are offset in the wefts 6 with respect to the butt joints. Correspondingly, the border profiles 41 and 42 can also be constructed from individual segments.

4 is a modified embodiment in a representation corresponding to FIG. 2 the area of the expansion joint between two shots. Components which correspond to the embodiment according to FIG. 2 are identified by the same reference numerals as in FIG. 2, but with the index “a”, so that the drawing according to FIG. 4 largely excludes the explanations relating to FIGS. 2 and 3 yourself is understandable. Differences exist in that, in the embodiment according to FIG. 4, the cylindrical outer side walls of the border profiles 41 and 42a for the lower edge 15a and the upper edge 22a of the vertically adjacent joints 6a lie in a common plane, so that the cover band 43a is cylindrical receives. On the inside of the cover band 43a, there is an additional sealing band 44, which extends into the contact area on the border profiles 41a and 42a, where it results in an additional seal. The sealing tape 44 can be made of neoprene, for example.

Additional sealing of the gap area of the movement joint 39 or 39a can be achieved in both embodiments by additional sealing tapes 45 or 45a on the edges of the masking tapes 43 or 43a, so that overall a gradual penetration of moisture is reliably avoided despite the considerable relative movement that occurs can.

A further difference of the embodiment according to FIG. 4 to that of FIG. 2 is that a support bracket 14a for supporting the lower end face 35a of the lower edge 15a of the upper shot 6a is fastened in the bottom region of a support structure, designated overall by 46, which is fastened by a Bolt 37a for fixing the lower edge 15a of the upper shot 6a is penetrated, so that the angle rail 16 according to FIG. 2 is omitted. In the support structure 46, at least one guide pin 21a is fastened, in particular welded, which axially projects on its underside beyond the plane of the support bracket 14a and the support structure 46 and there forms the guide section for a guide sleeve 32a with a plastic bushing 33a, which is attached to a reinforcement 23a of the upper edge 22a of the lower shot 6a is provided. Compared to the embodiment according to FIG. 1, the lower angle rail 24 is omitted in that a bracket angle 26a carries the vertical guide sleeve 32a in one horizontal leg and with its other leg 29a, which is used for fastening to the upper edge 22a of the weft 6a, which in the embodiment according to FIG 4, however, runs vertically, is directly penetrated by the fastening bolts 31 a. The soft seal 40a arranged in the gap area of the movement joint 39a therefore lies directly against the end face 25a of the upper edge 22a of the lower weft 6a.

The support structure 46 is fastened in a manner not shown to a bracket 10 or the like, and is therefore fixed against the antenna mast 2, while the upper edge 22a of the lower section 6a with its reinforcement 23a while reducing or increasing the gap height of the expansion joint 39a compared to the lower one Edge 15a of the upper shot 6a is movable, the guide sleeve 32a sliding on the guide pin 21a.

As the above description shows, changes and modifications are possible in the illustrated exemplary embodiments without departing from the scope of the invention. For example, in kinematic reversal, the guide sleeve 32 or 32a can be assigned to the supporting structure 3, while a corresponding guide pin 21 or 21a, conversely, is assigned to the reinforcement 23 or 23a. If the hard foam material of the shots 6a can absorb tensile loads as well as compressive loads, it would also be possible to fix the upper edge 22 or 22a of each shot 6 or 6a on the supporting structure 3 and instead the lower edge 15 or 15a in a corresponding manner keep agile. It is essential in any case that there is no rigid fixing of the weft 6 or 6a on both sides to the adjacent weft or to the supporting structure 3 or 3a, so that the described relative movements of the individual wefts 6 or 6a relative to one another and relative to the associated supporting structures 3 are possible in order to avoid an expansion of tension in the material of the shots 6 and 6a in the scope of these relative movements.

Claims (9)

1. Tower-like sheathing (4; 4a) for protecting radio installations with a mast (2), especially antennas, against the influences of weather, with a multiplicity of sleeve-shaped sections (6; 6a) consisting of rigid foam material, especially based on polyurethane, which are arranged above one another coaxially to the mast (2) and which are supported against the mast (2), in several planes lying above one another, by means of supporting frameworks (3) fastened to the mast (2), characterised in that

a) each section (6; 6a) is separated from the adjacent section located above or below it by means of a movement joint (39; 39a),

b) each section (6; 6a) is fastened rigidly at one of its ends, preferably at its lower edge (15; 15a), to one of the supporting frameworks (3) and is retained so as to be axially movable at its other end, preferably at its upper edge (22; 22a),

c) the edge (22; 22a) of the axially movable end of each section (6; 6a) is bordered by a bordering profile (42; 42a) made of wear-resistant material and is provided with a reinforcement (23; 23a), by means of which the axially movable end is guided in a transverse direction relative to the axis (9) of the mast (2) so as to be secured in position on the supporting framework (3), and

d) the movement joint (39; 39a) is covered at least on its outside by a covering strip (43; 43a), in particular made of glass fibre-reinforced unsaturated polyester.

2. Sheathing according to claim 1, characterised in that the movement joint (39; 39a) is bridged by at least on soft gasket (40; 40a), in particular consisting of closed-cell neoprene foam, between end faces (25; 25a or 35; 35a) at the edges (15; 15a or 22; 22a), movable relative to one another, of the adjacent sections (6; 6a).

3. Sheathing according to claim 1 or 2, characterised in that at least the outer side wall of the bordering profile (42; 42a) engages under at least the slideable adjacent edge of the covering strip (43; 43a).

4. Sheathing according to one of claims 1 to 3, characterised in that a strip gasket (45; 45a) parallel to the edge is provided at each of the lateral edges of the covering strip (43; 43a).

5. Sheathing according to one of claims 1 to 4, characterised in that the covering strip (43; 43a) consists of a multiplicity of individual segment- shaped covering panels which butt against one another by means of preferably rebated joints.

6. Sheathing according to claim 5, characterised in that the joints of the covering panels are arranged offset relative to joints between individual segments of the sections (6; 6a).

7. Sheathing according to one of claims 1 to 6, characterised in that at least one vertical guide bolt (21; 21a) is fastened to the supporting framework (3) supporting the upper section (6; 6a), and the reinforcement (23; 23a) fastened to the upper edge (22; 22a) of the lower section (6; 6a) is mounted slideably on the said guide bolt.

8. Sheathing according to claim 7, characterised in that the reinforcement (23; 23a) has a guide sleeve (32; 32a) which engages around the guide bolt (21; 21 a).

9. Sheathing according to claim 8, characterised in that the guide sleeve (32; 32a) is lined with a bush (33; 33a) , in particular consisting of plastic, such as polyethylene.

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