JP2011006997A - Mounting structure of net for preventing snow drop - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure of a net for preventing snow drop for preventing the net for preventing snow drop from being broken and improving work efficiency of the work on a steel tower covered with the net.SOLUTION: This mounting structure for attaching the net 3 for preventing snow drop covering the steel tower 2 for power transmission from an outer side to the steel tower 2 includes: a frame 4 formed into a frame shape and provided with the net 3 stretched around it; and support fittings 5 attached to the steel tower 2 and protruding outward from the steel tower 2 to support the frame 4 and the net 3 stretched around the frame while they are apart from the steel tower 2 by the predetermined length and ensure a space among the steel tower, the frame, and the net.

Description

  The present invention relates to a mounting structure for attaching a snowfall prevention net to a steel tower for preventing icy and snow adhering to the steel tower from being scattered when it is peeled off.

  Generally, in a power transmission tower or the like, snow or ice adheres to a steel material in the winter, and the attached ice and snow sometimes grows into a lump. Although this lump is peeled off from the power transmission tower when the temperature rises, the lump may be scattered and fall around the power transmission tower.

  In patent document 1, the snow accretion prevention apparatus for preventing that snow and ice adhere to a steel tower is proposed. However, even when this snow accretion prevention device is provided, the above-mentioned snowfall may occur when the adhesion of snow or ice cannot be prevented.

  Therefore, the power transmission tower is covered with a snowfall prevention net from the outside so that a block of ice and snow falls into the tower of the power transmission tower.

  Conventionally, as a structure for attaching a snowfall prevention net to a power transmission tower, for example, there is a structure in which the edge of the snowfall prevention net is bound to a main pillar material or a horizontal member of a power transmission tower using a binding tool such as a rope.

JP-A-5-263551

  However, in the conventional mounting structure, since the snowfall prevention net is directly attached to the power transmission tower, there is a problem that the snowfall prevention net hinders work and traffic on the power transmission tower.

  In addition, there was a problem that the snowfall prevention net fluttered with wind and caught by a step of a power transmission tower during strong winds.

  In addition, since the wind pressure load increases when a snowfall prevention net is attached to a power transmission tower, the snowfall prevention net is tied to the main pillar material of the power transmission tower and stored when no snow falls. It is conceivable that the snowfall prevention net is re-deployed during the snowfall period to cover the power transmission tower, but when the snowfall prevention net stretched between the main pillar materials is brought to one main pillar material during storage, it is deployed. When a snowfall prevention net brought to one of the main pillars is stretched between the main pillars, the worker needs to move between the main pillars, and the workability of deploying and storing the nets is poor. There was a problem.

  In addition, if a snowfall prevention net is provided in the vicinity of the charging section, the snowfall prevention net is charged by an induced voltage when wet, and the charged snowfall prevention net comes into contact with the steel tower to charge the snowfall prevention net. There was a problem that (static electricity) was discharged at once and the snowfall prevention net was melted.

  Therefore, an object of the present invention is to provide a snowfall prevention net mounting structure that solves the above-described problems and that can prevent the snowfall prevention net from being damaged and can improve workability in a steel tower on which the snowfall prevention net is stretched. There is.

  The invention according to claim 1 for achieving the above object is an attachment structure for attaching a snowfall prevention net that covers a steel tower from the outside to the steel tower, a frame that is formed in a frame shape and on which the snowfall prevention net is stretched, The steel tower, the frame, and the snow fall prevention are supported by the frame and the snow fall prevention net that is attached to the steel tower and is spaced apart from the steel tower by a predetermined length. It is provided with a support fitting that secures a space between the net.

  According to a second aspect of the present invention, a plurality of mounting rings are provided along the upper edge of the snowfall prevention net, and the mounting rings are inserted in the upper edge of the frame so as to be slidable in the horizontal direction. is there.

  According to a third aspect of the present invention, the frame and the support fitting are formed of a conductive material, and the snowfall prevention net is grounded to the steel tower via the frame and the support fitting.

  According to the first aspect of the present invention, since the snowfall prevention net stretched on the frame is supported in a state of being separated from the tower by a predetermined length, even if the snowfall prevention net flutters with the wind, the steps of the tower, etc. It is possible to prevent damage to the snowfall prevention net without being caught in the space, and to secure a work and traffic space between the steel tower and the snowfall prevention net, improving workability on the steel tower with a snowfall prevention net. Can be improved.

  According to the second aspect of the present invention, the mounting ring that is slidably inserted in the upper edge portion of the frame in the horizontal direction is provided along the upper edge portion of the snow fall prevention net. The snowfall prevention net can be easily deployed and stored by pulling the side edge of the suspended snowfall prevention net, improving the workability of deployment and storage. Can do.

  According to the third aspect of the invention, since the snowfall prevention net is grounded to the steel tower via the frame formed of a conductive material and the support bracket, the snowfall prevention net is installed in the vicinity of the charging unit. However, the snowfall prevention net is not charged by the induced voltage of the charging unit, and the snowfall prevention net can be prevented from being melted.

FIG. 1 is a schematic structural diagram of a steel tower targeted by a snowfall prevention net mounting structure according to an embodiment of the present invention. 2A to 2C are schematic cross-sectional views of the tower body of the present embodiment. FIG. 2A shows an upper stage in the upper part of the tower body, and FIG. FIG. 2 (c) shows the lower part of the tower body. FIG. 3 is a schematic partial view of the net of this embodiment. FIG. 4 is a schematic perspective view of the snowfall prevention net mounting structure of the present embodiment, and shows the upper part of the tower body. FIG. 5 is a schematic perspective view of the snow fall prevention net mounting structure of the present embodiment, and shows a state in which the snow fall prevention net is omitted in FIG. 4. FIG. 6 is a schematic partial perspective view of the snowfall prevention net mounting structure of the present embodiment, and shows the lower part of the tower body. FIG. 7 is a schematic perspective view of the snow fall prevention net mounting structure of the present embodiment, showing a state in which the snow fall prevention net is housed.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  The snow fall prevention net mounting structure (hereinafter referred to as mounting structure) of the present embodiment is intended for a power transmission tower, for example.

  First, a schematic structure of a power transmission tower and a snowfall prevention net will be described with reference to FIGS. In the following description, for convenience of explanation, the vertical direction in FIG. 2 is the front-rear direction (bottom is front, top is rear), and the left-right direction in FIG. 2 is left-right direction (however, left and right are opposite to FIG. 2). To do.

  As shown in FIG. 1, the power transmission tower 2 includes a tower body 11 that extends upward (substantially vertically upward) from the ground (base part), and a plurality of braces 12 provided on the tower body 11.

  The tower 11 includes a plurality of main column members 13a-13d extending vertically, an oblique member 14 tilted between the main column members 13a-13d, and a main column member 13a-13d. It has a horizontal member 15 stretched horizontally, and has a truss structure in which these members 13-15 are combined.

  As shown in FIG. 2, the tower body 11 is formed to have a rectangular cross section (substantially square shape in the illustrated example), and main pillar members 13 a to 13 d are respectively arranged at corners of the square.

  The main column members 13a to 13d are formed in a columnar shape, for example, formed by joining a plurality of steel pipes up and down. The main column members 13a to 13d are inclined to the inside of the tower body 11 so that the cross section of the tower body 11 becomes smaller as it reaches the upper side. As shown in FIG. 4, the main pillar members 13a to 13d are provided with a step 16 and a guide rail 18 (see FIG. 2C) for raising and lowering workers. The guide rails 18 are respectively attached to lower portions (tower lower portion L) of the two main column members 13c and 13d disposed on the rear side (left rear and right rear).

  Returning to FIG. 1, four pairs of the arm brackets 12 are arranged on the upper portion U of the tower body with an interval in the vertical direction. Each pair of arm brackets 12 extends from the tower body 11 to the outside in the left-right direction, and a transmission line 19 is held at the tips of the lower three pairs of arm brackets 12. Each arm 12 includes an arm metal main member 21 extending horizontally from the main column member 13a-13d to the left and right, and a suspension member 22 or a support member 23 extending from the main column member 13a-13d while being inclined to the left and right.

  A tower body 11 of the power transmission tower 2 is covered with a snowfall prevention net (hereinafter referred to as a net) 3.

  As shown in FIG. 2 and FIG. 4, the net 3 of the present embodiment is provided on two adjacent surfaces among the front, rear, left and right surfaces partitioned between the main pillar members 13a to 13d, and is seen in a plan view L. It is arranged in a letter shape. The surface on which the net 3 is stretched is set on the leeward side based on the wind direction during the snowfall season at the place where the transmission tower 2 is installed. In the illustrated example, the net 3 is attached to the front surface and the left side surface of the tower body 11. Further, the net 3 is arranged side by side along the tower 11 and is omitted in the lowermost panel that is not affected by snowfall.

  As shown in FIGS. 3 and 4, the net 3 includes a rectangular net 31, a surrounding rope 32 surrounding the net 31, an upper edge (upper end) and a lower edge of the net 31 (the surrounding rope 32). And a plurality of attachment rings 33 provided along the edge (lower end).

  The mesh 31 is formed in a trapezoidal shape whose upper side is shorter than the lower side so as to correspond to the shape of the surface partitioned between the main column member 13a and the main column member 13b (13d). The shape of the mesh 31 is not limited to this, and various shapes such as other rectangular shapes (for example, a rectangle) are conceivable.

  The net cloth 31 is a knotless net formed by knotting knots without knots, and has a substantially square mesh shape. The mesh of the net 31 is set to about 1 cm or more and less than about 10 cm. This is because when the mesh size is less than about 1 cm, the wind pressure load applied to the power transmission tower 2 increases, and when it exceeds about 10 cm, there is a possibility that a lump of snow or ice may slip through the net 3. Because. The network 31 is not limited to a knotless network, and various types such as a Russell network are conceivable.

  The peripheral rope 32 is provided along the peripheral edge of the net 31, and the end of the net yarn is wound around the peripheral rope 32 and bound. In addition, a securing rope 34 (see FIG. 4) for bundling the net 3 is attached to the surrounding rope 32 when the net 3 described later is stored. A plurality of the lashing ropes 34 are provided on both sides of the net 3 with an interval in the vertical direction.

  The net 31, the surrounding rope 32, and the securing rope 34 are formed from synthetic resin fibers (for example, polyethylene). Note that the material of the mesh 31 and the like is not limited to this, and various materials are possible.

  The attachment ring 33 is provided over the entire length of the net 31 (the surrounding rope 32) at an upper edge portion (and a lower edge portion) at an interval. The attachment ring 33 is formed of a conductive metal (for example, steel), and is bound and fixed to the surrounding rope 32 by the synthetic resin fiber string or the like.

  In order to attach this net 3 to the tower body 11 of the power transmission tower 2, the tower body 11 is provided with the mounting structures 1 and 10 of this embodiment. The mounting structure 1, 10 has a snowfall prevention net 3 installed on the power transmission tower 2 to prevent ice and snow adhering to the power transmission tower 2 from being scattered nearby and falling, and ice snow is attached to the net 3. It is intended to prevent and mitigate falling and scattering by letting it naturally melt after the weather recovers.

  As will be described in detail later, in the mounting structures 1 and 10, in order to install the net 3 on the tower body 11, a chevron, a steel pipe, and a wire are used as the frame 4 for partitioning the net 3. Moreover, a band material, an angle material, and a steel pipe material are used as the support metal fitting 5 for fixing the frame 4 to the main pillar materials 13a, 13b, and 13d of the tower body 11.

  Here, the installation of the net 3 in the tower body 11 is roughly classified into a tower upper part U (also referred to as an upper neck part) and a tower lower part L (also referred to as a neck lower part). A mountain-shaped material and a steel pipe material are used for the frame 4 above the boundary line B between the tower upper portion U and the tower lower portion L, and a wire is used for the lower frame 4.

  That is, the mounting structures 1 and 10 are different between the tower upper portion U in the vicinity of the charging unit (power transmission line 19) and the tower lower portion L below the tower upper portion U. The boundary line B between the tower upper part U and the tower lower part L is a line in consideration of workability due to separation from the charging part. The boundary line B between the tower upper part U and the tower lower part L is set based on the voltage of the charging unit and the distance from the transmission line 19, for example, about 4 m at 66 kV and about 5 m at 154 kV downward from the transmission line 19. It is set at a position of about 7 m at 275 kV and about 11 m at 500 kV.

  Next, the mounting structure 1 in the tower upper part U is demonstrated based on FIG. 4 and FIG.

  As shown in FIGS. 4 and 5, the mounting structure 1 in the tower upper portion U includes a frame 4 that is formed in a frame shape and on which the net 3 is stretched, and is attached to the tower body 11 and projects outward from the tower body 11. A support bracket 5 for supporting the frame 4 and the net 3 stretched on the frame 4 with a predetermined distance from the tower body 11 to secure a space between the tower body 11 and the frame 4 and the net 3. With. In the mounting structure 1 of the tower upper part U, the frame 4 and the support metal fitting 5 are provided for each net 3.

  The support fitting 5 includes a gripping portion 35 that grips the outer periphery of the main pillar members 13a, 13b, and 13d, and an overhang portion 37 (38, 39) that extends from the gripping portion 35 to the outside of the tower body 11 and to which the frame 4 is joined. ).

  The gripping portion 35 is attached to the main pillar members 13a, 13b, and 13d so as to support the four corners of each net 3 (frame 4) while being spaced apart vertically by the vertical length of the net 3. In the present embodiment, the gripping portion 35 attached to the main column member 13a between the front surface and the side surface is shared by the front surface support metal 5 and the side surface support metal 5.

  Each gripping portion 35 is made of a band material surrounding the main pillar members 13a, 13b, and 13d. Here, since the holding part 35 has the same structure in the tower upper part U and the tower lower part L, it demonstrates based on Fig.6 (a), (b) which showed the thing of the tower lower part L. FIG.

  As shown in FIGS. 6 (a) and 6 (b), the gripping portion 35 is composed of a pair of halved members formed in a halved cylindrical shape, and radially outwards at both ends in the circumferential direction of the halved members. A flange 36 is provided. The grip portion 35 is fixed to the main column members 13a, 13b, and 13d by fastening the flanges 36 of both halved members with bolts and fastening the main column members 13a, 13b, and 13d. Overhang portions 37 (38, 39) are joined to the grip portion 35.

  The overhang portions 37-39 of the present embodiment have different shapes on the front side and the side surface side. Furthermore, the shape of the protruding portions 38 and 39 on the side surface side is different between a portion (lower stage) below the lowermost brace 12 and a portion (upper stage) above the lower stage.

  First, the front side overhang portion 37 will be described.

  As shown in FIG. 2 (a), the overhang portion 37 on the front side is formed in an I-shape in plan view, and is linearly forward from the grip portion 35 (outside of the tower body 11 in the direction perpendicular to the net 3). Extend. The overhanging portion 37 overhangs a predetermined length (hereinafter referred to as a first overhanging length e1) outside the tower body 11 in consideration of a work space for workers. The overhang portion 37 is made of, for example, a plate material or an angle material.

  Next, the overhanging portion 38 on the side surface in the upper stage of the tower upper portion U will be described.

  The upper side of the tower upper part U (upper neck) is on the main column members 13a and 13d in the I-shaped overhanging portion 37 from the structural surface that would interfere with the brace main material 21 and the suspension material 22 and the like. Is difficult to install. Therefore, the overhanging portion 38 has a predetermined length overhanging offset on the inner side of the tower body 11 in the front-rear direction in order to avoid interference with members attached to the main column members 13a and 13d (arm metal main member 21 and suspension member 22). Is done. The overhanging portion 38 has a predetermined length (hereinafter referred to as a second overhanging length e2) shorter than the overhanging portion 37 on the front side, due to the clearance relationship with the charging unit, outside the tower body 11 in the left-right direction. Overhang.

  More specifically, the upper projecting portion 38 is formed in an L shape in plan view, and extends from the gripping portion 35 to the inside in the front-rear direction (inside the tower body 11 in the direction parallel to the net 3). An extending portion 42 that extends from the tip of the escape portion 41 to the left (outside of the tower body 11 in the direction orthogonal to the net 3). In the overhanging portion 38, for example, the escape portion 41 is made of a steel pipe material, and the extension portion 42 is made of a plate material or a chevron, and the escape portion 41 and the extension portion 42 are joined to each other by welding.

  Next, the side overhanging portion 39 in the lower stage of the tower upper portion U will be described.

  As shown in FIG. 2B, the lower overhang portion 39 is formed in an I shape like the front surface overhang portion 37, and the overhang length is set shorter than that of the front surface overhang portion 37. . In other words, on the lower side surface side, the overhang length of the overhang portion 39 is set to the second overhang length e2 in consideration of the clearance with the charging unit. The overhang portion 39 is made of a plate material or a mountain-shaped material.

  The grip part 35 and the overhang part 37-39 are joined and formed integrally by welding or the like, for example.

  Here, as the first overhanging length e1, the operator can easily pass between the frame 4 and the main pillar material 13, and the net 3 stretched on the frame 4 is connected to the main pillar material 13. A length that does not interfere with the attached accessory member (projection such as step 16) can be considered. The first overhang length e1 is set to 500 mm or more and less than 1000 mm, more preferably about 750 to 800 mm (human body width).

  This is because when the first overhang length e1 is less than 500 mm, the human body width is not secured in inspection or the like, which hinders work, and when it is 1000 mm or more, the frame strength increases and the effect of snowfall protection decreases. is there.

  The first overhang length e1 is appropriately set in consideration of this force because the force applied to the overhang portion 37 (and the tower body 11) increases as the length increases.

  Further, as the second overhanging length e2, an operator can pass between the frame 4 and the main column member 13, the attachment member of the main column member 13 does not interfere with the net 3, and the distance from the charging unit Can be sufficiently long. The second overhang length e2 is set based on the distance from the power transmission line 19 (clearance from the electric wire), but the concept of the overhang length under the condition that the clearance can be secured is the same as e1.

  Returning to FIG. 4, the frame 4 includes two vertical frames 46 extending vertically along the main pillar members 13 a, 13 b, and 13 d, and two horizontal frames 47 spanned between the upper and lower ends of the vertical frames 46. And is formed in a rectangular shape as a whole. More specifically, the frame 4 has a trapezoidal shape similar to the net 3, and the upper horizontal frame 47 is formed shorter than the lower horizontal frame 47.

  The vertical frame 46 is stretched between the upper and lower overhang portions 37. The vertical frame 46 extends above and below the overhanging portion 37, and the horizontal frame 47 is attached to the extended portion.

  More specifically, the vertical frame 46 is made of a chevron with an L-shaped cross section and has two surfaces that are orthogonal to each other. One surface (metal fitting surface) is disposed so as to be orthogonal to the net 3, and the overhanging portion 37 is superimposed on the metal fitting surface from the outside and joined to each other by a bolt. The other surface (horizontal frame joint surface) is arranged in parallel to the net 3, and the horizontal frame 47 is attached to the lateral frame joint surface from the outside by a U-bolt.

  The horizontal frame 47 is made of steel pipe material and has an outer diameter smaller than the inner diameter of the mounting ring 33 of the net 3. The mounting ring 33 is inserted into the horizontal frame 47 with play so that the mounting ring 33 can slide along the horizontal frame 47. At both ends of the horizontal frame 47, stoppers are attached (not shown) that close both ends and restrict the movement in the longitudinal direction so that the horizontal frame 47 does not come off the vertical frame 46.

  The support metal 5 and the frame 4 described above are formed of a conductive material (for example, steel), and the net 3 is grounded to the tower body 11 through the support metal 5 and the frame 4. When the power transmission tower 2 is a painted tower, a main member 13 or the like is provided with a ground member (line) that extends vertically along the tower body 11 and is grounded at one end. The support fitting 5 is connected to the ground member directly or via a conductive wire.

  As described above, the tower upper part U is close to the charging part, and it is necessary to stop power transmission for the installation / removal work of the net 3, but in the case of an important power transmission line, power transmission cannot be stopped easily. Basically, the frame 4 is always installed in the tower body 11. Therefore, the frame 4 for fixing the net 3 has a strong structure with certainty and safety by using a mountain-shaped material for the vertical frame 46 and a steel pipe material for the horizontal frame 47. The horizontal frame 47 is made of steel pipe in consideration of easy movement by the mounting ring 33 attached to the end of the net 3 when considering the storage and deployment of the net 3. For the vertical frame 46, a chevron is used in order to simplify the joining structure with the band material. A stainless steel band 67 was used to connect the vertical frame 46 and the net 3.

  Next, the mounting structure 10 in the tower lower part L will be described based on FIG.

  The mounting structure 10 in the tower lower part L differs from the mounting structure 1 in the tower upper part U mainly in the point that the frame 4 is a wire and the shape of the projecting portion of the support metal 5, and the other parts are almost the same. Have. Therefore, the same elements as those of the mounting structure 1 in the tower upper portion U are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, the mounting structure 10 in the tower lower portion L includes a frame 4 composed of wires 61 and 62, and a support fitting 5 having a grip portion 35 and an overhang portion 52 (37). In addition, in the mounting structure 10 at the tower lower portion L, the frame 4 and the support fitting 5 are shared by the nets 3 adjacent in the vertical direction.

  A plurality of gripping portions 35 are arranged on the main column members 13a, 13b, and 13d in the tower lower portion L so as to be vertically spaced from each other. The gripping portions 35 are arranged at positions corresponding to the upper edge of the uppermost net 3, between the nets 3 adjacent to each other in the vertical direction, and the lower edge of the lowermost net 3. Each gripping portion 35 is provided with an overhang portion 52 (37).

  The projecting portions 52 and 37 of the tower lower portion L are provided with a support fitting 5 fixed to the left rear main pillar member 13d having the guide rail 18 and other support fittings 5 fixed to the front main pillar members 13a and 13b. And the shape is different.

  As shown in FIG. 2 (c), the overhanging portion 52 of the guide rail mounting leg is offset by projecting to the inside of the tower body 11 in the front-rear direction to avoid contact with the guide rail 18, and is a space for workers. Is projected to the outside of the tower body 11 in the left-right direction with the first overhanging length e1.

  More specifically, the overhanging portion 52 has substantially the same structure as the overhanging portion 38 on the side surface of the upper stage in the tower upper portion U, and is formed in an L shape in a plan view, and the escape portion 54 and the extending portion. 55. The length of the escape portion 54 in the tower lower portion L is set shorter than the escape portion 41 in the tower upper portion U.

  On the other hand, the other overhanging portion 37 has the same structure as the overhanging portion 37 on the front surface side in the tower upper portion U, is formed in an I-shape in plan view, and extends from the grip portion 35 to the first overhanging length e1. . That is, since the tower lower part L is away from the charging part, the overhanging length of the overhanging part 37 is set to the first overhanging length e1 even on the side surface side.

  A plate-like bracket 56 for holding the frame 4 is provided at the tip of the overhang portion 37 as shown in FIG. The bracket 56 is formed with a lateral coupling hole 57 for coupling a later-described lateral wire 62 of the frame 4. Further, a pressing plate (not shown) for holding and holding a vertical wire 62 (described later) of the frame 4 between the bracket 56 and the bracket 56 is joined (for example, bolted). The pressing plate or bracket 56 is formed with a recess that extends vertically and into which the vertical wire 61 is fitted.

  As shown in FIG. 6 (b), the vertical coupling hole 59 for coupling the vertical wire 61 is formed in the bracket 56 of the lowermost (and uppermost) overhanging portion 37. A bracket similar to the bracket 56 is also provided at the tip of the extending portion 55 of the L-shaped overhanging portion 52. The bracket 56 is joined to the overhang part 37 (or the extension part 55) in advance by welding or the like before installation on the power transmission tower 2.

  Next, the frame 4 of the tower lower part L will be described. In addition, since the frame 4 of the tower lower part L has the same structure by the front side and the side surface side, only the front side frame 4 is demonstrated below and description for the side surface side is abbreviate | omitted.

  The frame 4 has two vertical wires 61 extending vertically along the main pillars 13a and 13b, and a plurality of horizontal wires 62 spanned between the vertical wires 61, and as a whole, a ladder shape. Formed. In this frame 4, a frame for stretching each net 3 is formed by two horizontal wires 62 arranged vertically and a vertical wire 61 between the horizontal wires 62.

  The vertical wire 61 extends between the bracket 56 and the pressing plate in the vertical direction from the uppermost bracket 56 to the lowermost bracket 56. Winding grips 66 are respectively attached to both ends of the vertical wire 61, and the winding grips 66 are respectively coupled to the vertical coupling holes 59 of the uppermost and lower brackets 56.

  The horizontal wire 62 extends horizontally between the vertical wires 61. A winding grip 66 is attached to both ends of the lateral wire 62, and the winding grip 66 is coupled to the lateral coupling hole 57 of the bracket 56.

  The horizontal wire 62 is disposed at a position corresponding to the upper edge or the lower edge of the net 3, and the mounting ring 33 of the net 3 is slidably inserted into the horizontal wire 62. The illustrated horizontal wires 62 are shared by the vertically adjacent nets 3, and the attachment rings 33 of the upper and lower nets 3 are alternately inserted into the horizontal wires 62.

  The vertical wire 61 and the horizontal wire 62 are formed of a conductive material (for example, steel), and the net 3 is grounded to the tower body 11 through the vertical wire 61, the horizontal wire 62, and the support fitting 5.

  The frame 4 at the lower part L of the tower body is separated from the charging part, and does not need to have a very strong structure. Therefore, a wire that has been used in the power transmission tower 2 is used as a frame 4 and is used for supporting the net 3 vertically and horizontally. The lower part L of the tower body has a structure in which the vertical wires 61 are not divided for each division of the net 3, and the horizontal wires 62 are shared by the upper and lower nets 3. That is, when the horizontal wire 62 is used in the lower part L of the tower body, it is common to the upper and lower frames.

  Next, the operation of the mounting structures 1 and 10 according to the present embodiment will be described based on FIGS. 4 and 7.

  In order to install the mounting structures 1, 10 of the present embodiment on the power transmission tower 2, first, the holding portion 35 of the support metal 5 is attached to the main pillar members 13 a, 13 b, 13 d of the tower body 11 and bolted to the support metal 5. Is fixed to the main pillars 13a, 13b, 13d.

  Next, the frame 4 and the net 3 are attached to the overhang portions 37-39, 52 of the support metal fitting 5 fixed to the main pillar members 13a, 13b, 13d.

  In the tower upper part U, the vertical frame 46 is bolted to the overhang portions 37-39, and the horizontal frame 47 is attached to the vertical frame 46 together with the net 3. That is, the attachment ring 33 of the net 3 is inserted in the horizontal frame 47 in advance, and the horizontal frame 47 is bolted to the vertical frame 46 with a U-shaped bolt. Further, the net 3 is spread between the vertical frames 46, and the edges of the net 3 are bound to the vertical frames 46 by stainless steel bands 67. As a result, the net 3 is stretched in a state without slack (a state in which tension is applied) (see FIG. 4).

  Similarly, in the tower lower part L, after attaching the vertical wire 61 to the bracket 56 previously fixed to the overhang | projection parts 52 and 37, the horizontal wire 62 is attached to the vertical wire 61 with the net | network 3. Further, the edge of the net 3 is bound to the vertical wire 61 by the stainless steel band 67, and the net 3 is stretched without slack.

  Here, in the mounting structures 1 and 10 of the present embodiment, the frame 4 and the net 3 stretched on the frame 4 by the projecting portions 37 to 39 and 52 of the support metal 5 are separated from the tower body 11 by a predetermined distance (first They are separated by the overhang length e1 or the second overhang length e2).

  Therefore, a space where workers can enter is secured between the frame 4 and the net 3 and the tower body 11, and work and traffic on the power transmission tower 2 are performed even when the net 3 is stretched. It can be performed easily and workability and safety can be improved.

  Further, even if the net 3 is vibrated by the wind or bent to the leeward side, the net 3 is not caught by the step 16 of the main pillar members 13a to 13d, and the damage to the net 3 can be prevented.

  Further, when the net 3 is spread between the vertical frames 46, the mounting ring 33 of the net 3 is guided by the horizontal frame 47 or the horizontal wire 62, so that the net 3 can be easily developed.

  Further, the net 3 attached by the attachment structures 1 and 10 of the present embodiment is swept away by the wind when the snow or ice lump attached to the tower body 11 is peeled off from the tower body 11 and dropped. It is possible to prevent scattering to the outside, and to prevent snowfall around the power transmission tower 2.

  Here, when the net 3 is stretched over the power transmission tower 2, the wind receiving area of the power transmission tower 2 is increased by the amount of the net 3 and a large wind pressure load is applied to the power transmission tower 2. Thus, since the net 3 has a large influence (stress) due to the wind, in the present embodiment, the net 3 is stored and removed in the high temperature period other than the snowfall period.

  As shown in FIG. 7, the removal work of the net 3 in the tower upper portion U is difficult near the charging unit, and therefore the net 3 is accommodated in the tower upper portion U. In other words, the tower upper portion U stores the net 3 close to one of the vertical frames 46 except during the winter (low temperature period) when snow falls.

  When storing, first, the stainless steel band 67 connected to the vertical frame 46 on the opposite side to the vertical frame 46 on the storage side is cut to disengage the vertical frame 46 on the opposite side from the net 3. Next, the net 3 is slid toward the storage-side vertical frame 46 and brought close to the storage side, and the lashing ropes 34 on both side edges of the net 3 are tied together and the net 3 is connected with the lashing rope 34. Tie up. As a result, the net 3 is stored and the wind receiving area is reduced. In addition, the frame 4 (an angle steel, a steel pipe) and the support metal fitting 5 of the tower upper part U are always installed in the tower 11.

  Thus, according to this embodiment, since the net 3 can be slid along the horizontal frame 47, the net 3 can be stored quickly and easily. The tower lower part L is not related to the charging part, so the net 3 is removed. The frame 4 (wires 61 and 62) and the support metal fitting 5 at the lower part L of the tower body are always installed.

  In addition, since the support fitting 5 and the frame 4 are formed of a conductive material, the net 3 can be prevented from being melted due to the influence of the charging portion in the tower upper portion U. That is, when the net 3 is stretched on the upper portion U of the tower body, the net 3 and the charging unit are close to each other, so that there is a possibility that the net 3 melts and breaks when wet (especially when dry) due to electrostatic induction of the charging unit. is there. In the present embodiment, the net 3 can be prevented from being melted by grounding the net 3 to the power transmission tower 2 via the frame 4 and the support fitting 5.

  By making the frame 4 different in the tower upper part U and the tower lower part L, both safety and economy can be achieved. That is, in the upper part U of the tower close to the charging part, the frame 4 is formed of a structural material such as a tube material or an angle material, so that it is less likely to be damaged than the case where the frame 4 is formed of a wire and an electric accident is more likely to occur. It can be surely prevented. On the other hand, in the lower part L of the tower body where there is no risk of electrical accidents, the frame 4 is formed of wire, so that material costs and manufacturing costs can be reduced compared to the case where the frame 4 is formed of a structural material.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  For example, the above-described embodiment is directed to a power transmission tower having a truss structure. However, the present invention is not limited to this, and the target steel tower may be a power transmission tower other than the truss structure, or for communication other than the power transmission tower. A steel tower may be used.

  In the above-described embodiment, the net is stretched on two adjacent surfaces among the four surfaces on the front, rear, left and right sides of the tower body, but is not limited to this. For example, as shown by a dotted line in FIG. 2, nets may be provided on all four surfaces (entire surface), or only one surface may be used depending on the tower and the direction of the wind.

  In the above-described embodiment, the frame has a different structure between the tower upper part and the tower lower part. However, the structure is not limited to this, and the same structure may be used for the tower upper part and the tower lower part. For example, all the frames may be formed from wires, and in this case, the manufacturing cost can be reduced.

  Moreover, in the above-mentioned embodiment, although the attachment ring was provided in both the upper edge part of the net | network and the lower edge part, it is not limited to this, It can also consider attaching only to an upper edge part.

1, 10 Mounting structure 2 Transmission tower (steel tower)
3 Net (Snowfall prevention net)
4 Frame 5 Support bracket

Claims (3)

  In the mounting structure for attaching a snowfall prevention net covering the steel tower from the outside to the steel tower, a frame is formed in a frame shape and the snowfall prevention net is stretched, and the frame is attached to the steel tower and projects outward from the steel tower. And a support fitting for supporting a snowfall prevention net stretched on the frame in a state spaced apart from the steel tower by a predetermined length to secure a space between the steel tower and the frame and the snowfall prevention net. A snowfall prevention net mounting structure characterized by that.   The attachment of the snow fall prevention net according to claim 1, wherein a plurality of attachment rings are provided along an upper edge portion of the snow fall prevention net, and the attachment ring is slidably inserted in the upper edge portion of the frame in the horizontal direction. Construction.   The tower is a power transmission tower, the frame and the support bracket are formed of a conductive material, and the snowfall prevention net is grounded to the tower via the frame and the support bracket. 2. A structure for mounting a snowfall prevention net according to 2.

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