Lead-in wire support structure and auxiliary tool for cross arm

Abstract

To provide a lead-in wire support structure for anchoring a lead-in wire for power distribution to an electric pole.SOLUTION: A lead-in wire support structure 1 includes: a linear main arm portion 2; a sub-arm portion 3 provided near at least one end portion in a longitudinal direction of the main arm portion 2 and projecting in a direction crossing an axial center of the main arm portion 2; a first lead-in wire locking portion 4 provided in a projecting manner at an end portion on a side not connected to the main arm portion 2 in the sub-arm portion 3; and a first fixing structure 6 for attaching the main arm portion 2 on a peripheral side surface of an electric pole 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drop wire support structure for fastening a distribution drop wire to a utility pole. [Background technology]

[0002] First, a conventional utility pole equipped with a dedicated lead-in arm and its related equipment will be described with reference to FIGS. 6 to 9. FIG. Fig. 6A is a side view of a utility pole equipped with a conventional drop-only arm, Fig. 6B is a front view of the same utility pole, and Fig. 7 is a perspective view of the conventional drop-only arm. Generally, when installing a drop line in a house or building, for example, as shown in Figure 6B, a low-voltage drop line 81 (see Figures 6A and 6B) is branched off from a low-voltage line 80, and this low-voltage drop line 81 is pulled down to a drop-in dedicated arm 50 (conventional product) installed on a utility pole 100.Furthermore, a drop line 56 (see Figures 8 to 9 below) is installed in each house or building via a bindless insulator 55 (see Figures 8 to 9 below) or the like on a drop line locking portion 52 protruding from the longitudinal end of this drop-in dedicated arm 50. In the following description, as shown in Figures 6A and 6B, the installation direction (horizontal direction) of the low-tension wire 80 is defined as the "X direction," the extension direction (vertical direction) of the utility pole 100 is defined as the "Z direction," and the direction toward the back of the paper in Figure 5 is defined as the "Y direction."

[0003] Furthermore, as shown in FIG. 7 , a conventional drop-in arm 50 includes a main arm section 51 made of steel and formed, for example, in the shape of a straight rectangular cylinder; drop wire locking sections 52 protruding from each longitudinal end of the main arm section 51 and formed, for example, in a fan-shaped flat plate made of steel with a plurality of drop wire locking holes 52a formed radially in the plate; and a fixing structure 53 provided in the center of the main arm section 51 for attaching the main arm section 51 to the peripheral side surface of the utility pole 100 so that the axis of the main arm section 51 is disposed substantially horizontally. Furthermore, as shown in FIG. 7, for example, the fixing structure 53 in the conventional pulling-only arm 50 is made of, for example, an L-shaped steel material, and includes a pair of guide members 53a, 53a fixed to the surface of the main arm section 51 that faces the peripheral side surface of the utility pole 100, two pairs of elongated holes 51a formed to penetrate a pair of side surfaces of the main arm section 51 (the surface on the front side of the paper in FIG. 7 and the surface on the back side of the paper) and through which U-bolts 53b that fix the main arm section 51 to the peripheral side surface of the utility pole 100 are inserted, and nuts 53c, 53c screwed onto the ends of the U-bolts 53b.

[0004] Furthermore, when a drop wire is supported using a conventional drop-only arm 50 as shown in FIG. 6, the following problems arise. Here, problems that arise when using the conventional pull-in exclusive arm 50 will be described in detail with reference to FIGS. Fig. 8A is a view (front view) of a utility pole equipped with a conventional lead-in dedicated cross arm as seen from the Y direction, and Fig. 8B is a view (side view) of the same utility pole as seen from the X direction. Furthermore, Fig. 9 is a cross-sectional view taken along the line S1-S1 in Fig. 8A. A utility pole 100 equipped with a dedicated service arm 50 that supports a service line 56 that supplies power to a house, building, etc. may be equipped with so-called low-voltage cables 63 such as communication cables in addition to electric wires (e.g., low-voltage wires 80 in Figure 5) (see Figures 8 and 9). Furthermore, to prevent workers from touching the electric wires (such as the low-voltage wire 80 in Figure 5) strung on the utility pole 100 and getting electrocuted during installation or maintenance of this low-voltage cable 63, the low-voltage cable 63 is usually installed about 1 m vertically below the installation position of the lead-in arm 50 (conventional product). More specifically, the low-voltage cable 63 is held on the utility pole 100 by the low-voltage cable support structure 60 . Furthermore, as shown in Figures 8 and 9, this low-voltage cable support structure 60 comprises a support arm 61 that protrudes in a direction that intersects (more specifically, is approximately perpendicular to) the axial direction of the pull-in-only arm 50 and in the radial direction of the utility pole 100, and a fixing band 62 that fixes this support arm 61 to the peripheral side of the utility pole 100.

[0005] As shown in Figures 8 and 9, when a drop wire 56 is moored via a bindless insulator 55 to a drop wire engaging portion 52 of a drop-only arm 50 attached to a utility pole 100 on which a low-voltage cable 63 is erected, there are cases where a sufficient separation distance P (preferably 60 cm or more) cannot be secured between the drop wire 56 moored to the drop-only arm 50 and the low-voltage cable 63, as shown in Figure 8B. At present, no prior application has been found that has the same problem to be solved as the present invention. However, prior applications in the same technical field are known, such as "Drop-in Arm" (Japanese Utility Model Application Publication No. 2-146925; Patent Document 1) and "Drop-in Wire Arm" (Japanese Patent Publication No. 54-30491; Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 2-146925 [Patent Document 2] Japanese Unexamined Patent Publication No. 54-30491 Summary of the Invention [Problem to be solved by the invention]

[0007] Since the arms for drop lines disclosed in Patent Documents 1 and 2 all have substantially the same shape as the conventional drop-in-only arm 50 shown in Figure 7 above, even when using the arms disclosed in Patent Documents 1 and 2, it was not possible to ensure a sufficient separation distance P between the low-voltage cable 63 and drop line 56 installed on the utility pole 100 as shown in Figures 8 and 9.

[0008] The present invention has been made in response to such conventional circumstances, and its purpose is to provide a drop wire support structure that can ensure sufficient distance between a low-voltage cable and a drop wire when the drop wire is fastened to a utility pole on which the low-voltage cable is installed. Another object of the present invention is to provide an auxiliary device for a cable arm that can be retrofitted to a conventional cable arm to enable the conventional cable arm to be used as a cable support structure according to the present invention. [Means for solving the problem]

[0009] A first invention for solving the above problems provides a drop wire support structure comprising: a straight main arm portion; a sub-arm portion that protrudes from at least one longitudinal end of the main arm portion in a direction intersecting the axis of the main arm portion; a first drop wire locking portion that protrudes from the end of the sub-arm portion that is not connected to the main arm portion; and a first fixing structure that attaches the main arm portion to the circumferential side of a utility pole. In the first aspect of the invention having the above configuration, the main arm portion acts as a support member for the sub arm portion. Furthermore, when the main arm section is attached to the utility pole, the sub-arm section has the effect of positioning and holding the first drop wire engaging section at a position that is the length of the sub-arm section, based on the attachment position of the sub-arm section in the longitudinal direction of the main arm section, and at approximately the same vertical height as the main arm section. The first drop wire anchoring portion also functions to support (anchor) the end of the drop wire on the side not laid in the house or building. Furthermore, the first fixing structure has the effect of attaching the main arm section to the peripheral side surface of the utility pole while maintaining the axis of the main arm section substantially horizontal.

[0010] A second invention is the above-mentioned first invention, characterized in that a second drop wire locking portion is provided to protrude from an end portion in the longitudinal direction of the main arm portion. In the second invention having the above configuration, in addition to the end of the sub-arm section that is not connected to the main arm section, the longitudinal end of the main arm section can also support (moor) the end of the drop line that is not arranged in the building or house.

[0011] The third invention is the above-mentioned first or second invention, characterized in that the first drop line engaging portion is positioned at a position farther from the utility pole than the position where the low-voltage cable is arranged when the drop line support structure is viewed in a plan view with the main arm portion attached to the utility pole. In the third invention having the above configuration, the distance (separation distance) between the first drop line locking portion (the drop line anchored in the first drop line locking portion) and the low-voltage cable can be made greater than the distance between the low-voltage cable and the main arm portion in the vertical direction. In other words, according to the third invention, the difference between the installation height of the low-voltage cable on the axis of the utility pole and the installation height of the main arm section on the same axis becomes the effective separation distance between the drop wire and the low-voltage cable moored to the first drop wire engaging section.

[0012] A fourth invention is the first or second invention described above, characterized in that a sub-arm section is provided at each of the longitudinal ends of the main arm section, the planar shape of a connected body consisting of the main arm section and the two sub-arm sections is U-shaped, and the distance X between the two sub-arm sections satisfies (L1+L2+L3)≦X, where L1 is the diameter of the utility pole on which the drop wire support structure according to the present invention is to be installed, and L2 and L3 are the diameters of the two transformers to be installed on this utility pole, respectively. According to the fourth invention having the above configuration, a space can be secured directly below the transformer installed on the utility pole where the drop line support structure and the drop line moored to this drop line support structure are not arranged. In this case, when a worker climbs up the utility pole to perform some work on a transformer installed on the pole, the fourth invention, the service line support structure, and the service line moored to this service line support structure, have the effect of preventing them from interfering with the worker's climb up the pole.

[0013] A fifth invention provides an auxiliary device for an arm that is retrofitted to a dedicated drop arm including a straight main arm portion, second drop wire engaging portions protruding from each of the longitudinal ends of the main arm portion, and a first fixing structure for attaching the main arm portion to a utility pole, and this auxiliary device is characterized by comprising: a sub-arm portion protruding from at least one longitudinal end of the main arm portion in a direction intersecting the axis of the main arm portion; a first drop wire engaging portion protruding from an end of the sub-arm portion on the side not connected to the main arm portion; and a second fixing structure provided on the end of the sub-arm portion on the side not equipped with the first drop wire engaging portion, for attaching the sub-arm portion to the circumferential surface of the main arm portion. In the fifth invention having the above configuration, the main arm portion supports the second drop wire locking portion at each of its longitudinal ends, and also has the effect of supporting the sub-arm portion via the second fixing structure near the installation position of the second drop wire locking portion. Furthermore, the first drop wire locking portion protruding from the end of the sub-arm portion on the side not including the second fixing structure has the same function as the first drop wire locking portion in the first aspect of the invention. Furthermore, the first fixing structure provided on the main arm portion has the same effect as the first fixing structure in the first aspect of the invention. In other words, the drop-in dedicated arm, which includes a straight main arm portion, second drop wire engaging portions protruding from each of the longitudinal ends of the main arm portion, and a first fixing structure for attaching the main arm portion to a utility pole, has the same configuration as the conventional drop-in dedicated arm (drop-in dedicated arm 50) shown in Fig. 7. Therefore, the fifth invention has the effect of enabling the conventional drop-in dedicated arm to be used as one having the same function as the drop wire support structure of the present invention. [Effects of the Invention]

[0014] According to the first invention of the drop wire support structure, the first drop wire locking portion can be positioned farther away from the peripheral side surface of the utility pole than the conventional drop wire locking arm (drop wire locking arm 50) shown in Figure 7 above. This makes it easy to ensure sufficient distance between the low-voltage cable installed on the utility pole on which the first invention is installed and the service line anchored to the first service line anchoring portion of the first invention.

[0015] According to the second aspect of the present invention, another drop line can also be moored (supported) at the longitudinal end of the main arm section. Therefore, according to the second invention, it is possible to widen the options for mooring (supporting) positions of the drop line. As a result, according to the second invention, it becomes easy to ensure sufficient distance between multiple service lines moored to the service line support structure and surrounding structures (e.g., houses or buildings, or pole-mounted equipment, etc.). Therefore, according to the second aspect of the present invention, it is possible to provide a drop wire support structure that is more convenient.

[0016] According to the third invention, sufficient distance can be ensured between the service line moored (supported) by the service line support structure of the present invention and the low-voltage cable installed on the utility pole to which this service line support structure is attached. As a result, when the service line bends and sags due to snow accumulation or the like, the risk of an accident occurring, such as the service line coming into contact with the low-voltage cable arranged below it and the low-voltage cable breaking, can be reduced. Therefore, according to the third aspect of the present invention, it is possible to improve safety when providing various services (power supply, communication services, etc.) provided via pole equipment.

[0017] According to the fourth aspect of the present invention, a space can be secured directly below the transformer installed on the utility pole, free from the drop wire support structure and the drop wires moored to the drop wire support structure, thereby improving safety and workability when workers climb the pole to work.

[0018] By using the arm auxiliary device of the fifth invention, a conventional drop-in arm (drop-in arm 50) such as that shown in Figure 7 above can be modified and used as the drop line support structure of the present invention. Therefore, according to the fifth aspect of the present invention, the convenience of the conventional pull-in dedicated arm can be significantly improved. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view of a drop wire support structure according to a first embodiment of the present invention. [Figure 2] 2A is a front view of a utility pole provided with a drop wire support structure according to Example 1, and FIG. 2B is a side view of a utility pole provided with a drop wire support structure according to Example 1. FIG. [Figure 3] FIG. 2B is a cross-sectional view taken along the line S2-S2 in FIG. 2A. [Figure 4] FIG. 10 is a perspective view of an arm assisting device according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a partial perspective view showing a state in which an arm auxiliary device according to a second embodiment is attached to a conventional pull-in arm. [Figure 6] (6A) is a side view of a utility pole equipped with a conventional dedicated lead-in arm, and (6B) is a front view of a utility pole equipped with a conventional dedicated lead-in arm. [Figure 7] FIG. 1 is a perspective view of a conventional retractable arm. [Figure 8] (8A) is a view (front view) of a utility pole equipped with a conventional dedicated lead-in arm as viewed from the Y direction, and (8B) is a view (side view) of a utility pole equipped with a conventional dedicated lead-in arm as viewed from the X direction. [Figure 9] FIG. 1 is a plan view of a utility pole equipped with a conventional dedicated lead-in arm as viewed from the Z direction. DETAILED DESCRIPTION OF THE INVENTION

[0020] A drop wire support structure and an auxiliary arm for an arm according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5. FIG.

[0021] [1-1: Regarding the drop line support structure according to Example 1] First Embodiment A structure of a drop wire support structure according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view of a drop wire support structure according to a first embodiment of the present invention. As shown in FIG. 1 , the drop wire support structure 1 according to the first embodiment includes a straight main arm section 2, a sub-arm section 3 protruding from at least one longitudinal end of the main arm section 2 in a direction intersecting the axis of the main arm section 2, a drop wire locking section 4 (first drop wire locking section) protruding from the end of the sub-arm section 3 that is not connected to the main arm section 2, and a fixing structure 6 (first fixing structure) for attaching the main arm section 2 to the peripheral side of a utility pole 40. Both the main arm section 2 and the sub-arm section 3 are made of steel and are formed into a straight rectangular tube.

[0022] Furthermore, the drop wire locking portion 4 is a fan-shaped flat plate made of, for example, steel material, with a plurality of (for example, four) drop wire locking holes 52a formed radially therein. The sub arm 3 is also provided with two drop wire locking portions 4, one on each of the upper and lower surfaces of the end portion not connected to the main arm 2. More specifically, the linear sides of the fan-shaped drop wire locking portions 4 are fixed to the upper and lower surfaces of the end portion of the sub arm 3, for example, by welding. The number of drop wire locking portions 4 protruding from the end of the sub-arm portion 3 does not necessarily have to be two, and may be, for example, only one. As shown in FIG. 1 , for example, the fixing structure 6 is made of, for example, an L-shaped steel material, and includes a pair of guide members 6a fixed to the surface of the main arm section 2 that faces the peripheral side of the utility pole 40, two pairs (four) of elongated holes 2a that are formed to penetrate a pair of side surfaces of the main arm section 2 (the surface on the front side of the page and the surface on the back side of the page in FIG. 1) and through which U-bolts 6b that fix the main arm section 2 to the peripheral side of the utility pole 40 are inserted, and a pair of nuts 6c that are screwed onto the ends of the U-bolts 6b to fix the main arm section 2 and the U-bolts 6b to the peripheral side of the utility pole 40.

[0023] The structure of the fixing structure 6 does not need to be limited to that shown in FIG. 1, and may be formed, for example, by a curved steel band plate (not shown), linear bolts (not shown), and nuts. Alternatively, the fixing structure 6 may have a structure other than the above, as long as it can fix the main arm section 2 to the peripheral side surface of the utility pole 40 with its axis aligned substantially horizontally.

[0024] In addition, in the drop wire support structure 1 according to Example 1, the angle formed by the axis of the sub-arm portion 3 relative to the axis of the main arm portion 2 may be set to 90° so that the drop wire locking portion 4 can be positioned at a more distant position in the horizontal direction relative to the peripheral side surface of the utility pole 40. Furthermore, for the same reason, it is desirable that the connection position of the sub arm 3 in the longitudinal direction of the main arm 2 be set close to the end of the main arm 2 in the longitudinal direction. Furthermore, although FIG. 1 illustrates an example in which two sub-arms 3 are provided protruding from the peripheral side surface of the main arm 2, only one sub-arm 3 may be provided protruding from either one of the longitudinal ends of the main arm 2. Furthermore, while Figure 1 shows an example in which two sub-arm sections 3 are provided protruding in the same direction from the peripheral side surface of the main arm section 2, the two sub-arm sections 3 may be provided protruding alternately from the side surface of the main arm section 2 depending on the installation location of the drop line support structure 1. In addition, in the drop line support structure 1 of Example 1, as described above, the purpose is to position the drop line locking portion 4 at a position further away in the horizontal direction based on the peripheral side surface of the utility pole 40, so it is desirable to position the axis of the sub-arm portion 3 approximately horizontally.

[0025] [1-2: Effects of the drop wire support structure according to Example 1] Fig. 2A is a front view of a utility pole equipped with the drop wire support structure according to Example 1, and Fig. 2B is a side view of the utility pole equipped with the same drop wire support structure. Furthermore, Fig. 3 is a cross-sectional view taken along line S2-S2 in Fig. 2A. In the following description, as shown in Figures 2 and 3, the horizontal direction is defined as the "X direction," the direction in which utility pole 40 extends (vertical direction) is defined as the "Z direction," and the direction toward the back of the paper in Figure 2A is defined as the "Y direction." As shown in Figures 2 and 3, when using the drop line support structure 1 of Example 1, the low-voltage cable 23 is installed by the low-voltage cable support structure 20 at a position approximately 1 m vertically downward from the installation position of the drop line support structure 1 on the utility pole 40. 2 and 3, the low-voltage cable support structure 20 comprises a support arm 21 that protrudes in a direction that intersects (more specifically, is approximately perpendicular to) the axial direction of the main arm portion 2 in the drop line support structure 1 of Example 1 and in the radial direction of the utility pole 40, and a fixing band 22 that fixes this support arm 21 onto the peripheral side surface of the utility pole 40.

[0026] When using the lead-in wire support structure 1 according to Embodiment 1, as shown in FIGS. 2 to 3, the lead-in wire 9 is moored (supported) to the lead-in wire locking hole 4a (refer to the previous FIG. 1) of the lead-in wire locking portion 4 protruding from the end of the sub-arm portion 3 on the side not connected to the main arm portion 2. The primary side of the lead-in wire 9 locked to the non-insulated strain insulator 8 is connected to the lead-in wire terminal box 7 installed on the sub-arm portion 3 or the main arm portion 2, and its primary side is further connected to the secondary side of a transformer or a low-voltage wire not shown in the figure.

[0027] And, as shown in FIGS. 2B and 3, when using the lead-in wire support structure 1 according to Embodiment 1, the lead-in wire locking portion 4 protrudes from the tip of the sub-arm portion 3, and the primary side (the side where the non-insulated strain insulator 8 is provided) of the lead-in wire 9 is moored (supported) to the lead-in wire locking hole 4a (refer to the previous FIG. 1) formed in this lead-in wire locking portion 4. In this case, compared with the case of using the conventional dedicated lead-in arm fitting (dedicated lead-in arm fitting 50) shown in the previous FIG. 7, based on the side surface E (refer to FIG. 2B) arranged to face the circumferential side surface of the utility pole 40 in the main arm portion 2, the lead-in wire locking portion 4 can be arranged at a position at least separated by the length F of the sub-arm portion 3 (refer to FIG. 2B). And, when the height difference between the main arm portion 51 of the dedicated lead-in arm fitting 50 installed on the utility pole 100 shown in FIGS. 8 to 9, where the conventional example was described previously, and the weak electric cable 63 is the same as the height difference between the main arm portion 2 of the lead-in wire support structure 1 installed on the utility pole 40 shown in FIGS. 2 to 3 and the weak electric cable 23, by mooring (supporting) the primary side of the lead-in wire 9 to the lead-in wire locking portion 4 of the lead-in wire support structure 1 shown in FIGS. 1 to 3, a separation distance Q sufficiently larger than the separation distance P shown in the previous FIG. 8B can be ensured between the lead-in wire 9 and the weak electric cable 23.

[0028] Therefore, according to the lead-in wire support structure 1 according to Embodiment 1, even when the installation position of the lead-in wire support structure 1 on the utility pole 40 and the arrangement position (Y-direction position) of the weak electric cable 23 are set the same as those in the conventional examples of FIGS. 8 to 9, a sufficient separation distance Q (where P < Q) can be ensured between the lead-in wire 9 and the weak electric cable 23. In this case, when the service line 9 bends and droops due to snow accumulation or the like, the risk of the service line 9 coming into contact with the low-voltage cable 23 arranged vertically below it can be reduced, thereby reducing the risk of an accident such as the low-voltage cable 23 breaking. As a result, safety during use of pole-mounted equipment (electric wires and low-voltage cables) can be significantly improved.

[0029] [1-3: Regarding the detailed structure and modified examples of the drop line support structure according to Example 1] (Regarding the positional relationship between the drop line locking part and the low-voltage cable) As shown in Figures 2B and 3, in the drop wire support structure 1 of Example 1, when the drop wire support structure 1 is viewed in plan with the main arm portion 2 attached to the peripheral side surface of the utility pole 40, the position of the drop wire locking portion 4 protruding from the tip of the sub-arm portion 3 may be set to be farther away from the peripheral side surface of the utility pole 40 than the position of the low-voltage cable 23. In this case, the separation distance Q between the drop wire 9 and the low-voltage cable 23 can be made larger than when the installation position of the drop wire engaging portion 4 in the drop wire support structure 1 of Example 1 is closer to the circumferential surface of the utility pole 40 than the installation position of the low-voltage cable 23, relative to the circumferential surface of the utility pole 40, that is, when the length F of the sub-arm portion 3 in Figure 2B is shorter than the length of the support arm 21 in the low-voltage cable support structure 20. Therefore, according to the drop wire support structure 1 of Example 1 in which the positional relationship between the drop wire locking portion 4 and the low-voltage cable 23 is specified as described above, the separation between the drop wire 9 and the low-voltage cable 23 can be achieved more reliably. Therefore, it is possible to provide a drop wire support structure 1 with higher performance.

[0030] (Addition of drop line locking section) As shown in FIG. 1 above, the drop wire support structure 1 of Example 1 may also be provided with a drop wire locking portion 5 (second drop wire locking portion) at the longitudinal end of the main arm portion 2, separate from the drop wire locking portion 4. In this case, in addition to the drop line locking portion 4 at the tip of the sub-arm portion 3, another drop line (not shown) can be moored (supported) at the drop line locking portion 5 protruding from the longitudinal end of the main arm portion 2. As a result, when there are multiple houses or buildings to which power needs to be supplied around utility pole 40, the options for mooring (supporting) positions for the primary side of the service line to supply power to each house or building can be expanded. In this case, it becomes easy to ensure sufficient distance between the multiple service lines moored to the service line support structure 1 of Example 1 and structures around the utility pole 40 (e.g., houses or buildings, or pole-mounted equipment, etc.). Therefore, when the drop wire support structure 1 according to the first embodiment includes the drop wire locking portion 5 in addition to the drop wire locking portion 4, it is possible to provide a drop wire support structure that is more convenient.

[0031] (Regarding the form of the drop line support structure) As shown in FIGS. 1 to 3 , when the drop wire support structure 1 according to the first embodiment includes sub-arms 3 at both longitudinal ends of the main arm 2, and when the planar shape of the connected body formed by the main arm 2 and the two sub-arms 3 is U-shaped, the structure may further include the following features. More specifically, as shown in Figures 2A and 3, when the diameter of the utility pole 40 is L1 and the diameters of the two transformers 30a and 30b installed on this utility pole 40 are L2 and L3, respectively, the distance X between the two sub-arm portions 3, 3 may be configured to satisfy (L1 + L2 + L3) ≤ X. In this case, a space can be secured directly below the transformers 30a, 30b installed on the utility pole 40 in which the service line support structure 1 of Example 1 and the service line 9 anchored to the service line anchoring portion 4 (and service line anchoring portion 5) of this service line support structure 1 are not arranged. In this case, when a worker climbs up the utility pole 40 to perform some work on the transformer 30a or the transformer 30b, the service line support structure 1 itself and the service line 9 moored to the service line locking portion 4 or the service line locking portion 5 of this service line support structure 1 can be prevented from obstructing the worker's climb up the pole. Therefore, according to the drop wire support structure 1 of Example 1 in which the planar shape of the connected body consisting of the main arm section 2 and the two sub arm sections 3 is U-shaped and the distance X between the two sub arm sections 3 is specified as described above, it is possible to further improve the safety and workability when the worker climbs up to work.

[0032] Furthermore, if the protruding direction of the two sub arm sections 3 on the main arm section 2 coincides with the direction in which the utility pole 40 is arranged relative to the main arm section 2 (see Figures 2B and 3), when a worker climbs up the utility pole 40, the connected body consisting of the main arm section 2 and the sub arm section 3 is unlikely to interfere with the climbing operation. In this case, it is possible to provide a drop wire support structure 1 that allows workers to work on the utility pole 40 more easily.

[0033] (Regarding the telescopic structure of the sub-arm) Although not particularly shown, the sub-arm portion 3 of the drop wire support structure 1 according to the first embodiment may have an extendable structure. This telescopic structure may be configured such that, for example, straight steel material with a U-shaped cross section is nested on the peripheral side of the sub-arm section 3 so that the U-shaped steel material can slide in the axial direction of the sub-arm section 3, and the overlapping portion of the U-shaped steel material and the sub-arm section 3 can be fixed using fixing devices consisting of, for example, bolts and nuts so that the sub-arm section 3 can be maintained at the desired length. In this case, the length of the sub-arm portion 3 of the drop wire support structure 1 according to the first embodiment can be changed as desired. As a result, the length of the sub-arm portion 3 can be freely adjusted depending on the proximity of surrounding structures, etc. to the utility pole 40 to which it is to be attached, thereby improving the convenience of the drop line support structure 1 of Example 1.

[0034] [2: Regarding the arm support device according to Example 2] Second Embodiment A description will be given of an arm auxiliary device and a drop wire support structure including the same according to a second embodiment of the present invention with reference to FIGS. Fig. 4 is a perspective view of an arm assisting device according to a second embodiment of the present invention, and Fig. 5 is a partial perspective view showing a state in which the arm assisting device according to the second embodiment is attached to a conventional pull-in dedicated arm. The arm auxiliary device 10 of Example 2 is an auxiliary device to be retrofitted to a conventional drop-in dedicated arm 50' that includes a straight main arm portion 51', drop wire locking portions 52' (second drop wire locking portions) protruding from each of the longitudinal ends of the main arm portion 51', and a fixing structure 53' (first fixing structure) for attaching the main arm portion 51' to a utility pole 40. More specifically, the arm auxiliary device 10 according to the second embodiment includes a sub-arm 11 protruding from one or both longitudinal ends of a main arm 51′ of a dedicated drag arm 50′ in a direction intersecting the axis of the main arm 51′, a drop wire locking portion 12 (first drop wire locking portion) protruding from the end of the sub-arm 11 on the side not connected to the main arm 51′, and a fixing structure 13 (second fixing structure) provided at the end of the sub-arm 11 on the side not having the drop wire locking portion 12, for attaching the sub-arm 11 to the peripheral side of the main arm 51′.

[0035] In addition, the sub-arm portion 11 in the arm auxiliary device 10 of Example 2 has a configuration equivalent to the sub-arm portion 3 in the drop line support structure 1 of Example 1, and its material, shape, and structure are the same as those of the sub-arm portion 3. Furthermore, the drop wire locking portion 12 in the arm auxiliary device 10 according to Example 2 has a configuration corresponding to the drop wire locking portion 4 in the drop wire support structure 1 according to Example 1, and is made of the same material, has the same shape, and has the same structure as the drop wire locking portion 4. In other words, the drop wire locking hole 12a of the drop wire locking portion 12 corresponds to the drop wire locking hole 4a of the drop wire locking portion 4.

[0036] Furthermore, as shown in FIG. 4, the fixing structure 13 in the arm auxiliary device 10 according to the second embodiment is made of a flat steel plate, and is joined individually to the upper and lower surfaces of the sub-arm portion 11, with a pair of support plates 13a partially protruding from the end of the sub-arm portion 11 on the side not having the drop wire locking portion 12, bolt insertion holes 13b formed through the thickness of the support plates 13a, bolts 13c inserted into the bolt insertion holes 13b, and nuts 13d screwed onto the shafts of the bolts 13c. In addition, the fixing structure 13 shown in FIG. 4 is described as an example in which a pair of (two) support plates 13a are fixed to the sub-arm portion 11, but in addition to this, a steel material with a U-shaped cross section may be connected to the end of the sub-arm portion 11, or other structures may be adopted. In other words, the fixing structure 13 may have a structure other than that described above as long as it can firmly attach the end of the sub-arm portion 11 to the main arm portion 51' of the retraction-only arm 50' and has sufficient durability.

[0037] FIG. 5 shows a state in which the arm auxiliary tool 10 according to the second embodiment is attached to a main arm portion 51' of a conventional pull-in arm 50'. That is, the drop wire support structure 1' according to the second embodiment is composed of a conventional drop-only arm 50' and the arm auxiliary device 10 according to the second embodiment. Moreover, the drop wire support structure 1' according to the second embodiment has the same effects as the drop wire support structure 1 according to the first embodiment shown in FIG. Furthermore, according to the arm auxiliary device 10 of Example 2, a conventional drop-in dedicated arm 50' (existing product) can be modified and used as the drop wire support structure 1' of Example 2. As a result, the convenience and versatility of the conventional drop-in dedicated arm 50' can be improved.

[0038] Although not particularly shown, the sub-arm portion 11 of the arm assisting device 10 according to the second embodiment may have an extendable structure. This telescopic structure may be configured such that, for example, straight steel material with a U-shaped cross section is nested on the peripheral side of sub-arm section 11 so that the steel material with a U-shaped cross section can slide in the axial direction of sub-arm section 11, and the overlapping portion of the steel material with a U-shaped cross section and sub-arm section 11 can be fixed using fixing devices consisting of, for example, bolts and nuts so that the sub-arm section 11 can be maintained at the desired length. In this case, the length of the sub-arm portion 3 of the arm assisting device 10 according to the second embodiment can be changed as desired. As a result, the length of the sub-arm portion 11 can be adjusted depending on the proximity of surrounding structures, etc. to the utility pole 40 to which it is to be attached, thereby improving the convenience of the drop line support structure 1' of Example 2. [Industrial Applicability]

[0039] As described above, the present invention is a service line support structure that secures a distribution service line to a utility pole, or an auxiliary arm that enables a conventional service line-only arm to be used as the service line support structure of the present invention, and can be used in technical fields related to power transmission equipment. [Explanation of symbols]

[0040] DESCRIPTION OF SYMBOLS 1, 1'... Drop wire support structure 2... Main arm section 2a... Elongated hole 3... Sub-arm section 4... Drop wire locking section (first drop wire locking section) 4a... Drop wire locking hole 5... Drop wire locking section (second drop wire locking section) 5a... Drop wire locking hole 6... Fixing structure (first fixing structure) 6a... Guide member 6b... U-bolt 6c... Nut 7... Drop wire terminal box 8... Bindless insulator 9... Drop wire 10... Arm auxiliary device 11... Sub-arm section 12... Drop wire locking section (first drop wire locking section) 12a... Drop wire locking hole 13... Fixing structure (second fixing structure) 13a... Support plate 13b... Bolt insertion hole 13c... Bolt 13d... Nut 20... Low-voltage cable support structure 21...Support arm 22...Fixing band 23...Low-voltage cable 30a, 30b...Transformer 40...Utility pole 50, 50'...Dedicated lead-in arm (conventional product) 51, 51'...Main arm portion 51a, 51a'...Elongated hole 52, 52'...Lead-in wire locking portion (second lead-in wire locking portion) 52a, 52a'...Lead-in wire locking hole 53, 53'...Fixing structure (first fixing structure) 53a, 53a'...Guide member 53b, 53b'...U-bolt 53c, 53c'...Nut 54...Lead-in wire terminal box 55...Bindless insulator 56...Lead-in wire 60...Low-voltage cable support structure 61...Support arm 62...Fixing band 63...Low-voltage cable 70a, 70b...Transformer 80...Low-voltage wire 80 81...Low voltage downline 100...Utility pole

Claims

1. A main arm portion having a straight line shape; a sub-arm portion provided near at least one longitudinal end of the main arm portion and projecting in a direction intersecting an axis of the main arm portion; a first drop wire locking portion protruding from an end portion of the sub arm portion that is not connected to the main arm portion; A drop wire support structure comprising a first fixing structure for mounting the main arm portion on a peripheral side surface of a utility pole.

2. 2. The drop wire support structure according to claim 1, further comprising a second drop wire locking portion protruding from an end portion in the longitudinal direction of the main arm portion.

3. The service line support structure according to claim 1 or claim 2, characterized in that, when the service line support structure is viewed in plan with the main arm portion attached to the utility pole, the first service line engaging portion is positioned at a position farther from the utility pole than the position at which the low-voltage cable is arranged.

4. The main arm portion has the sub-arm portion at each of its longitudinal ends, a planar shape of a connected body consisting of the main arm portion and the two sub arm portions is U-shaped, The distance X between the two sub-arm portions is, when the diameter of the utility pole on which the drop line support structure is to be installed is L1 and the diameters of the two transformers to be installed on the utility pole are L2 and L3, respectively: (L1+L2+L3)≦X 3. The drop wire support structure according to claim 1, wherein the following is satisfied:

5. An auxiliary device to be retrofitted to a dedicated drop-in arm, the auxiliary device comprising: a main arm portion having a straight line shape; second drop-in wire engaging portions protruding from each of longitudinal ends of the main arm portion; and a first fixing structure for attaching the main arm portion to a utility pole, The auxiliary tool is a sub-arm portion provided near at least one longitudinal end of the main arm portion and projecting in a direction intersecting an axis of the main arm portion; a first drop line locking portion protruding from an end portion of the sub arm portion that is not connected to the main arm portion; an auxiliary device for an arm, characterized in that it comprises a second fixing structure provided at the end of the sub-arm portion on the side not provided with the first drop wire locking portion, and which attaches the sub-arm portion to the peripheral side surface of the main arm portion.

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