Buried electric wire inspection device

Abstract

To provide a buried electric wire inspection device which is inexpensive and does not require skill for inspection work.SOLUTION: A buried electric wire inspection device (40) for inspecting buried electric wires comprises a fixed part (41) to be placed at the end of the buried electric wire, a movable part (59) carried by an inspector, and a conductor (79) electrically connecting the movable part (59) and the fixed part (41). An inspection hole is drilled in the ground along the buried electric wire, a probe (60) is inserted into the inspection hole, and a needle (61) is electrically connected to the buried electric wire, thereby lighting one of a first color lamp and a second color lamp built in a two-color light-emitting diode (76). When the inspection hole is changed, the first color lamp changes to the second color lamp, or the second color lamp changes to the first color lamp, making it useful for finding broken parts of the buried electric wires.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a buried electric wire inspection device for inspecting buried electric wires buried in the ground. [Background technology]

[0002] In gardens, golf courses, and other places, grass is mowed regularly. In recent years, automatic lawnmowers have been introduced as a means of labor saving. Among automatic lawnmowers, autonomous lawnmowers that can be operated without a human driver are preferred. The mowing areas of gardens and golf courses are surrounded by buried electric wires called boundary wires. The autonomous mower electrically detects the buried electric wires and reverses direction. In this way, the autonomous mower moves vertically and horizontally within the mowing area to mow the grass.

[0003] The buried electric wire is approximately 300m long. Although buried electric wires are underground, they can be broken by being chewed on by field mice. When a break is suspected, the buried electric wire is excavated to find the broken part. The part is then repaired and backfilled. This is not an easy task, as the buried electric wire is about 300m long.

[0004] Therefore, a device for detecting a broken portion of a buried electric wire is desired and has been put to practical use (for example, see Patent Document 1 (FIG. 2)).

[0005] Patent Document 1 will be explained with reference to the following figure. FIG. 12 is a diagram for explaining the basic principle of the conventional technology. An electric wire EW is buried in the ground. An AC voltage VF1 with a frequency F1 is applied between one end of the buried electric wire EW and the ground, and an AC voltage VF2 with a frequency F2 is applied between the other end of the buried electric wire EW and the ground.

[0006] In FIG. 12, the normal distribution curve is a graph showing the pickup voltage VD, and this is ignored when the first electrode AT1 is applied to the ground surface. At this time, it is important that the first electrode AT1 is placed directly above the buried electric wire EW. A second electrode AT2 is placed on the ground surface to the side at a fixed distance from the first electrode AT1. When the frequency of the pickup voltage VD changes from F1 to F2, that point becomes the point of disconnection.

[0007] When the first electrode AT1 is placed directly above the buried electric wire EW, a nice normally distributed pickup voltage VD curve is obtained. On the other hand, if the first electrode AT1 is placed at a position shifted to the left or right from directly above the buried electric wire EW, the pickup voltage VD curve will have a distorted shape. Furthermore, when the second electrode AT2 approaches the first electrode AT1, the pickup voltage VD becomes smaller, which affects detection.

[0008] That is, although the technique of Patent Document 1 has the advantage that it is possible to detect a broken portion of the buried electric wire EW while it remains buried, it has drawbacks that cannot be overlooked. The drawbacks are as follows.

[0009] It is essential that the first electrode AT1 is placed directly above the buried electric wire EW. However, it is not easy to place the first electrode AT1 directly above the buried electric wire EW, which cannot be seen from the outside, and placing it directly above the wire requires skill. In other words, the inspection work requires skill. Furthermore, as shown in FIG. 1 of Patent Document 1, the buried electric wire breakage detection device is a complex structure including the piezoelectric oscillators OSCF1 and OSCF2, and is inevitably expensive.

[0010] The high cost and the skilled inspection work required are obstacles to the widespread use of buried electric wire break detection devices. To promote widespread use, there is a need for devices for detecting broken parts in buried electric wires that are inexpensive and do not require skilled inspection workers. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Publication No. 7-10303 Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a buried electric wire inspection device which is inexpensive and does not require skilled workers to carry out the inspection. [Means for solving the problem]

[0013] The invention according to claim 1 is a buried electric wire inspection device for inspecting buried electric wires buried in the ground, This buried electric wire inspection device comprises a stationary part to be placed at the end of the buried electric wire, a movable part carried by an inspector, and a conductor electrically connecting the movable part and the stationary part, the stationary portion comprises a battery box incorporating a first battery and a second battery, a first harness extending from the positive electrode of the first battery, a first clip provided at a tip of the first harness and electrically connected to one end of the buried electric wire, a second harness extending from the negative electrode of the second battery, a second clip provided at a tip of the second harness and electrically connected to the other end of the buried electric wire, a third harness extending from between the negative electrode of the first battery and the positive electrode of the second battery, and a third clip provided at a tip of the third harness, the movable portion comprises a probe having a groove for accommodating a part of the buried electric wire and a needle for contacting the buried electric wire, a fourth harness electrically connected to the needle and including a first color lamp and a second color lamp for emitting a color different from that of the first color lamp, and a fourth clip provided at a tip of the fourth harness; one end of the conductive wire is electrically connected to the third clip and the other end is electrically connected to the fourth clip; The device is characterized in that inspection holes are drilled in the ground at multiple locations along the buried electric wire, the probe is inserted into the inspection holes, and the needle is electrically connected to the buried electric wire, thereby lighting one of the first color lamp and the second color lamp, and when the inspection hole is changed, the first color lamp changes to the second color lamp, or the second color lamp changes to the first color lamp, thereby being used to find broken locations in the buried electric wire.

[0014] Although the fixed part can also be moved, it is called the fixed part because it is not moved when it is being used for testing. On the other hand, the movable part is called a movable part because it is moved along the buried electric wire during inspection.

[0015] The invention according to claim 2 is a buried electric wire inspection device for inspecting buried electric wires buried in the ground, This buried electric wire inspection device comprises a stationary part to be placed at the end of the buried electric wire, a movable part carried by an inspector, and a conductor electrically connecting the movable part and the stationary part, the stationary portion comprises a battery box incorporating a first battery and a second battery, a first harness extending from the positive electrode of the first battery, a first clip provided at a tip of the first harness and electrically connected to one end of the buried electric wire, a second harness extending from the negative electrode of the second battery, a second clip provided at a tip of the second harness and electrically connected to the other end of the buried electric wire, a third harness extending from between the negative electrode of the first battery and the positive electrode of the second battery, and a third clip provided at a tip of the third harness, the movable portion includes a fifth clip electrically connected to the buried electric wire, a fourth harness electrically connected to the fifth clip and including a first color lamp and a second color lamp emitting a color different from that of the first color lamp, and a fourth clip provided at a tip of the fourth harness; one end of the conductive wire is electrically connected to the third clip and the other end is electrically connected to the fourth clip; The device is characterized in that inspection holes are drilled in the ground at multiple locations along the buried electric wire, and the fifth clip is inserted into the inspection holes and electrically connected to the buried electric wire, thereby lighting one of the first color lamp and the second color lamp, and when the inspection hole is changed, the first color lamp changes to the second color lamp, or the second color lamp changes to the first color lamp, thereby being used to find broken locations in the buried electric wire.

[0016] The invention according to claim 3 is the buried electric wire inspection device according to claim 1 or claim 2, The first color lamp and the second color lamp are characterized in that they are built into one two-color light emitting diode. Effect of the Invention

[0017] In the invention of claim 1, the buried electric wire inspection device is composed of a battery box equipped with the first to third harnesses and the first to third clips, a fourth harness equipped with the fourth clip, a probe and first and second color lamps, and a simple conductor, so that the overall configuration is simple and inexpensive.

[0018] The essential work involves drilling an inspection hole in the ground, inserting a probe into the inspection hole, and electrically connecting the needle of the probe to the buried electric wire, but since this work is performed in a visible area, it does not require skill. That is, claim 1 provides a buried electric wire inspection device that is inexpensive and does not require skilled work to perform the inspection.

[0019] In the invention of claim 2, the buried electric wire inspection device is composed of a battery box having the first to third harnesses and the first to third clips, a fourth harness having the fourth clip, the fifth clip and the first and second color lamps, and a simple conductor, so that the overall configuration is simple and inexpensive.

[0020] Since the probe in claim 1 is replaced with an inexpensive fifth clip in claim 2, a buried electric wire inspection device is provided which is less expensive and does not require skilled inspection work.

[0021] In the invention according to claim 3, a two-color light emitting diode is adopted. By using one two-color light emitting diode rather than providing a first color lamp and a second color lamp, wiring can be simplified. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a side view showing an example of a wire embedding device. [Diagram 2] FIG. 2 is a plan view showing a garden and an autonomous grass cutter. [Diagram 3] 1 is a configuration diagram of a buried electric wire inspection device according to the present invention. [Figure 4] FIG. 2 is a basic configuration diagram of a stationary part. [Diagram 5] (a) is a cross-sectional view of the probe, and (b) and (c) are diagrams showing the operation of the probe. [Figure 6] (a) is a basic configuration diagram of a two-color light-emitting diode, and (b) and (c) are diagrams showing the operation of a two-color light-emitting diode. [Figure 7] 13(a) and 13(b) are diagrams illustrating the correlation between disconnection and light emission. [Figure 8] FIG. 2A is a diagram for explaining a method for detecting a broken portion using a buried electric wire inspection device according to the present invention, and FIG. 2B is an enlarged view of part b in FIG. [Figure 9] 11A and 11B are diagrams illustrating another method for detecting a broken wire location. [Figure 10] 11A and 11B are diagrams illustrating yet another method for detecting a broken wire location. [Figure 11] 11A and 11B are diagrams illustrating a modified example of the buried electric wire inspection device according to the present invention. [Figure 12] FIG. 1 is a diagram illustrating the basic principle of the prior art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. EXAMPLES

[0024] As shown in FIG. 1, a wire burying device 10 includes, for example, a body 11, a drive source 12 mounted on the body 11, a transmission shaft 13 driven by the drive source 12 and extending downward from the drive source 12, a horizontal drive shaft 14 rotated by the transmission shaft 13, a disk 15 attached to the horizontal drive shaft 14, a wire reel 16 disposed rearward of the disk 15 and mounted on the body 11, a wire guide 19 disposed rearward of the disk 15 and mounted on the body 11 for guiding and feeding buried electric wire 17 supplied from the wire reel 16 into a trench 18, and a resistance member 21 disposed rearward of the wire guide 19 and mounted on the body 11 for contacting the ground 20 and generating a resistance force.

[0025] The disk 15 serves both as a running wheel and a groove cutting wheel. The buried electric wire 17 is stored in the groove 18, and soil 22 is placed on the buried electric wire 17 and leveled by a leveling plate 23. As a result of the above, the buried electric wire 17 is buried in the ground 20.

[0026] The standard length of the buried electric wire 17 is 300 m (maximum length is 600 m). The buried electric wire 17 may be any of a twisted copper wire, a solid copper wire, a twisted aluminum wire, a solid aluminum wire, a twisted iron wire, and a solid iron wire. Moreover, the buried electric wire 17 may be either a covered electric wire or a bare electric wire.

[0027] As shown in FIG. 2, a buried electric cable 17 is laid in a garden 25 with one end 17a and the other end 17b remaining above ground, and a power source 26 is connected to one end 17a and the other end 17b of the buried electric cable 17. The autonomous grass cutter 30 includes drive wheels 31, a cutting blade 32, and a wire sensor 33, and cuts grass with the cutting blade 32 while traveling on the ground 20 with the drive wheels 31. When the wire sensor 33 detects the buried electric wire 17, it changes its direction of travel. In this way, the autonomous grass cutter 30 cuts grass while traveling vertically and horizontally within the buried electric wire 17.

[0028] Preferably, a current monitor 35 is provided between the power source 26 and the buried electric wire 17, and this current monitor 35 is provided with a normal lamp 36 which also serves as an operation lamp, an abnormality lamp 37 which indicates an abnormality, and an alarm buzzer 38 which issues an alarm. When current flows normally through the buried electric wire 17, the normal lamp 36 lights up. If the current is cut off due to a wire break or the like, an abnormality lamp 37 lights up and an alarm buzzer 38 sounds. If the manager of Garden 25 notices any abnormality, he or she will order an inspector to take action.

[0029] [Buried electric wire inspection device] The inspector carries out the inspection using a buried electric wire inspection device 40 described below. As shown in FIG. 3, buried electric wire inspection device 40 comprises stationary part 41, movable part 59 carried by an inspector, and conductor 79.

[0030] The movable portion 59 includes a probe 60 and a fourth harness 75 . The fourth harness 75 has a two-color light emitting diode 76 and an attachment plug 77 at its base, and has a fourth alligator clip 78 as a fourth clip at its tip.

[0031] The conductor 79 may be a general-purpose electric wire of about 100 to 200 m. The stationary portion 41 will be described in detail with reference to FIG.

[0032] [Fixed part] As shown in FIG. 4, the stationary portion 41 comprises a battery box 44 housing a first battery 42 and a second battery 43 arranged in series, a first harness 45 extending from the positive terminal of the first battery 42, a first alligator clip 46 as a first clip provided at the end of the first harness 45 and electrically connected to one end of the buried electric wire (FIG. 2, reference numeral 17), a second harness 47 extending from the negative terminal of the second battery 43, a second alligator clip 48 as a second clip provided at the end of the second harness 47 and electrically connected to the other end of the buried electric wire, a third harness 51 extending from between the negative terminal of the first battery 42 and the positive terminal of the second battery 43, a third alligator clip 52 as a third clip provided at the end of the third harness 51, and a slide switch 53.

[0033] Although not shown in FIG. 4, a protective element for preventing external short circuits is built into the battery box 44 to enhance protection for the inspector.

[0034] The first battery 42 is, for example, a 3V DC primary battery (dry cell) or a rechargeable secondary battery. The same is true for the second battery 43. With this level of voltage, there is no risk of electric shock, and the burden on inspectors is reduced. The slide switch 53 is preferably an illuminated switch that emits light when ON and goes out when OFF.

[0035] [probe] 5(a), the probe 60 is composed of a vertical bar 62 incorporating a needle 61 having a pointed lower end, a left horizontal bar 63 and a right horizontal bar 64 formed integrally with the upper part of the vertical bar 62, a finger hook 65 provided at the upper end of the needle 61, a biasing spring 66 that biases the needle 61 upward, and a socket 67 incorporated in the left horizontal bar 63. The socket 67 is electrically connected to the needle 61.

[0036] The vertical bar 62, the left horizontal bar 63 and the right horizontal bar 64 are made of a resin having electrical insulation properties. The vertical rod 62 has a groove 68 in its lower portion, and the lower end of the needle 61 enters and exits this groove 68 .

[0037] 5(b), the buried electric wire 17 is stored in the groove 68. Alternatively, the buried electric wire 17 is hooked onto the groove 68. In FIG. 5( a ), an index finger 71 is hooked on the left horizontal bar 63 , a middle finger 72 is hooked on the right horizontal bar 64 , and a thumb 73 is hooked on the finger hook portion 65 , and the finger hook portion 65 is pressed down. 5(c), the lower end of the needle 61 comes into contact with the buried electric wire 17. If the buried electric wire 17 is an insulated electric wire, the needle 61 breaks through the insulator and comes into contact with the metal electric wire.

[0038] Although detailed structure will be omitted, the needle 61 may be raised when the finger hook 65 is pressed down, in contrast to this embodiment. That is, normally, the needle 61 is lowered by the biasing force of the spring and protrudes into the groove 68 . When the finger hook 65 is pressed down, the needle 61 rises and moves away from the groove 68. The buried electric wire 17 is stored in this groove 68. When the thumb 73 is released, the needle 61 moves down and its tip (lower end) comes into contact with the buried electric wire 17. Therefore, the structure of the probe 60 may be changed arbitrarily.

[0039] [First color lamp and second color lamp] As shown in FIG. 6(a), the two-color light emitting diode 76 includes a first color lamp 76a and a second color lamp 76b that emits a color different from that of the first color lamp 76a. The emission color of the first color lamp 76a is, for example, red, and the emission color of the second color lamp 76b is, for example, yellow.

[0040] By inserting the attachment plug 77 into the socket 67 , the fourth harness 75 is electrically connected to the needle 61 .

[0041] 6(b), when the plug 77 side is positive (+) and the fourth alligator clip 78 side is negative (-), the first color lamp 76a lights up and the second color lamp 76b remains off. That is, the two-color light emitting diode 76 emits red light.

[0042] 6(c), when the plug 77 side is negative (-) and the fourth alligator clip 78 side is positive (+), the second color lamp 76b lights up and the first color lamp 76a remains off. That is, the bicolor LED 76 emits yellow light.

[0043] [Probe set and color] As shown in Fig. 7(a), it is assumed that buried electric wire 17 is broken at a broken point X. In this figure, buried electric wire 17 is exposed for ease of explanation. A first alligator clip 46 is clipped onto one end 17a of the buried electric wire 17, and a second alligator clip 48 is clipped onto the other end 17b.

[0044] Conductive wire 79 is extended, and one end of this conductive wire 79 is clipped with third alligator clip 52. The tip of the extended conductive wire 79 is clipped with fourth alligator clip 78. Then, the probe 60 is set at an arbitrary location on the buried electric wire 17 .

[0045] As shown in FIG. 7(a), when the probe 60 is set on the buried electric wire 17 between the broken location X and the first alligator clip 46, the bi-color light-emitting diode 76 next to the probe 60 held by the inspector glows red as the first color lamp (FIG. 6(b), symbol 76a) lights up (hereinafter, it will be referred to as "the bi-color light-emitting diode 76 glows red").

[0046] As shown in FIG. 7(b), when the probe 60 is set on the buried electric wire 17 between the broken location X and the second alligator clip 48, the bi-color light-emitting diode 76 next to the probe 60 held by the inspector glows yellow as the second color lamp (FIG. 6(c), symbol 76b) lights up (hereinafter referred to as "the bi-color light-emitting diode 76 glows yellow").

[0047] In FIG. 7(b), the probe 60 is located approximately 100 m away from the third alligator clip 52. If the bicolor light-emitting diode 76 were provided near the third alligator clip 52 (i.e., battery box 44 shown in FIG. 3, etc.), a second inspector would need to be placed near the bicolor light-emitting diode 76 in addition to the inspector holding the probe 60, resulting in increased labor costs. In this regard, in the present invention, since the two-color light emitting diode 76 is disposed near the probe 60 carried by the inspector, there is an advantage that the inspection work can be performed by a single inspector.

[0048] [Test method 1] An example of an inspection method performed by an inspector using the buried electric wire inspection device 40 configured as above will be described with reference to Figs. 8(a) and (b). The manager recognizes the abnormality when the abnormality lamp (Figure 2, symbol 37) lights up and / or the alarm buzzer (Figure 2, symbol 38) sounds, and orders an inspector to carry out an inspection. The inspector, carrying a buried electric wire inspection device (FIG. 3, reference numeral 40), heads to the garden (FIG. 2, reference numeral 25) and disconnects the buried electric wire 17 from the power source 26 in FIG.

[0049] 8(a), the inspector clips the first alligator clip 46 onto one end 17a of the buried electric wire 17, clips the second alligator clip 48 onto the other end 17b, clips the third alligator clip 52 onto the extended conductor 79, and clips the fourth alligator clip 78 onto the tip of the conductor 79.

[0050] In parallel (or next), a first inspection hole 81 is drilled near one end 17a of the buried electric wire 17 using a tool such as a shovel or spade to locally expose the buried electric wire 17. The inspector inserts the probe 60 into the first inspection hole 81 and sets it on (bites into) the buried electric wire 17. At this time, it is assumed that the two-color light emitting diode 76 lights up in red.

[0051] The standard circumference of the buried electric cable 17 is 300 m, with a maximum circumference of 600 m. On the other hand, the diameter of the first inspection hole 81 is about 0.1 m (10 cm). In FIG. 8(a), the first inspection hole 81 is drawn large for emphasis, but the first inspection hole 81 (and other inspection holes) are actually the size of a small dot.

[0052] Since the red color was confirmed, a second inspection hole 82 is drilled next to the first inspection hole 81. The inspector inserts the probe 60 into the second inspection hole 82, and sets the probe 60 on the buried electric wire 17. At this time, it is assumed that the two-color light-emitting diode 76 lights up in red. The above procedure is repeated for the third inspection hole 83 to the sixth inspection hole 86. It is assumed that all of the two-color light-emitting diodes 76 light up in red.

[0053] As a general rule, the inspection holes are drilled in the following order: drill the first inspection hole 81 → inspect → check the color → drill the second inspection hole 82 → inspect → check the color. However, in consideration of work efficiency, it is also possible to drill multiple inspection holes in advance (in this example, the first inspection hole 81 to the seventh inspection hole 87) and then perform inspection using the probe 60.

[0054] However, since it is buried, the inspector is unaware of the location of the disconnection X. In this example, the disconnection location X is between the sixth inspection hole 86 and the seventh inspection hole 87.

[0055] Next, the inspector inserts the probe 60 into the seventh inspection hole 87, and sets the probe 60 on the buried electric wire 17. At this time, the two-color light-emitting diode 76 lights up in yellow. That is, the color has changed.

[0056] As explained in FIG. 7(b), no matter where the probe 60 is set on the buried electric wire 17 from the seventh inspection hole 87 to the second alligator clip 48, all of the two-color light-emitting diodes 76 light up yellow. Therefore, in FIG. 8(a), there is no need to drill any inspection holes after the seventh inspection hole 87.

[0057] Then, based on the change in color, the inspector can recognize that the disconnection location X is between the sixth inspection hole 86 and the seventh inspection hole 87.

[0058] However, there is a distance of, for example, 20 m between the sixth inspection hole 86 and the seventh inspection hole 87. It is very difficult to dig up the buried electric wires 17 over this distance.

[0059] An example of such a measure will be described with reference to FIG. As shown in Fig. 8(b), a 6.5 inspection hole 88 is drilled between the sixth inspection hole 86 and the seventh inspection hole 87, and the probe 60 is set in the hole. At this time, the two-color light-emitting diode 76 lights up yellow. The 6.5th hole means the middle between the sixth and seventh holes.

[0060] Next, a 6.25 inspection hole 89 is drilled halfway between the 6 inspection hole 86 and the 6.5 inspection hole 88, and the probe 60 is set in the hole. At this time, the two-color light-emitting diode 76 lights up yellow. The 6.25 hole is halfway between the 6 and 6.5 holes.

[0061] Since the sixth inspection hole 86 is red and the 6.25th inspection hole 89 is yellow, it follows that the broken portion X is located between the sixth inspection hole 86 and the 6.25th inspection hole 89. The distance between the sixth inspection hole 86 and the sixth inspection hole 89 was 1 / 4, or 5 m. At this distance, it is easy to dig up the buried electric wire 17.

[0062] In Fig. 8(b), it is acceptable to drill the 6.125th inspection hole between the 6th inspection hole 86 and the 6.25th inspection hole 89, thereby further halving the excavation distance to 2.5 m. The number of inspection holes can be determined arbitrarily, taking into account the balance between the effort required to drill the inspection holes and the effort required to excavate the buried electric wires 17.

[0063] According to the present embodiment described above, as explained with reference to FIG. 3, the fixed part 41 and the movable part 59 are sufficiently small and sufficiently inexpensive. 8(a), no skill is required to set the probe 60 on the exposed buried electric wire 17. In addition, since only the color emitted by the two-color light-emitting diode 76 is identified, no skill is required for this identification. As a result, the present invention provides a buried electric wire inspection device (FIG. 3, reference numeral 40) that is inexpensive and does not require skilled workmanship to perform the inspection.

[0064] Incidentally, the inspection of the buried electric wire 17 is started when the abnormality lamp 37 in Fig. 2 lights up or the alarm buzzer 38 sounds. In this case, the number of broken points X is, in principle, one. If there is only one break, the inspection procedure based on Figs. 8(a) and (b) is effective.

[0065] However, if there is a delay before the start of the inspection, it is possible that field mice may nibble at other parts of the wire, resulting in multiple breaks. The frequency of multiple breaks occurring is very low, but it cannot be said to be non-existent. The buried electric wire inspection device 40 of the present invention can also detect breaks in a plurality of places. This will be described below.

[0066] [Test method 2] An example in which there are two disconnection locations X will be described with reference to FIG. Assume that in addition to the break location X, a second break location X2 exists between the seventh inspection hole 87 and the second alligator clip 48, as shown in FIG. As in FIG. 8(a), when the probes 60 in FIG. 9 were inserted into the first inspection hole 81 to the sixth inspection hole 86 and set on the buried electric wire 17, the two-color light-emitting diode 76 was red.

[0067] Next, the probe 60 is inserted into the seventh inspection hole 87 and set on the buried electric wire 17. At this time, the two-color light-emitting diode 76 does not light up in yellow and is unlit. This lack of light leads the inspector to suspect multiple broken wires.

[0068] Therefore, the inspector drills an n-th inspection hole 91 near the second alligator clip 48 (the other end 17b of the buried electric wire 17), inserts the probe 60, and sets it on the buried electric wire 17. At this time, the two-color light-emitting diode 76 was yellow. Next, the (n-1)th inspection hole 92 is drilled at a position closer to the seventh inspection hole 87 than the nth inspection hole 91, and the probe 60 is inserted and set on the buried electric wire 17. At this time, the two-color light-emitting diode 76 was yellow.

[0069] Next, the (n-2)th inspection hole 93 is drilled at a position closer to the seventh inspection hole 87 than the (n-1)th inspection hole 92, and the probe 60 is inserted and set on the buried electric wire 17. At this time, the two-color light-emitting diode 76 is not lit. The inspector recognizes that the second disconnection location X2 is located between the (n-1)th inspection hole 92 and the (n-2)th inspection hole 93. That is, the broken portion X can be recognized by the change from red to unlit, and the second broken portion X2 can be recognized by the change from yellow to unlit.

[0070] Incidentally, since the frequency of multiple disconnections is low and the majority of cases have only one disconnection, the previously described "Inspection Method 1" is mainly applied. A modification of "Inspection method 1" will be described below with reference to Figs. 10(a) to (d).

[0071] [Test method 3] 10(a), a first inspection hole 81 is drilled at a location sufficiently far (preferably the farthest) from one end 17a and the other end 17b of the buried electric wire 17. A probe 60 is inserted into this first inspection hole 81 and set on the buried electric wire 17.

[0072] If the two-color LED 76 is "red", the area between the first inspection hole 81 and the first alligator clip 46 is sound, and a break is suspected between the first inspection hole 81 and the second alligator clip 48. Alternatively, if the bi-color LED 76 is "yellow", the section between the first inspection hole 81 and the second alligator clip 48 is sound, and a break is suspected between the first inspection hole 81 and the first alligator clip 46.

[0073] In Fig. 10(a), the bi-color LED 76 is "red", a break is suspected between the first inspection hole 81 and the second alligator clip 48, and this interval is the next inspection target. Since the interval between the first inspection hole 81 and the first alligator clip 46 is sound, this interval is excluded from the inspection target thereafter.

[0074] 10(b), a second inspection hole 82 is drilled in the middle of the next inspection target (between the first inspection hole 81 and the second alligator clip 48). The probe 60 is inserted into this second inspection hole 82 and set on the buried electric wire 17. The bi-color light emitting diode 76 was "yellow." The area between the second inspection hole 82 and the second alligator clip 48 was healthy, and the area between the second inspection hole 82 and the first inspection hole 81 was to be the next inspection target.

[0075] 10(c), a third inspection hole 83 is drilled in the middle of the next inspection target (between the second inspection hole 82 and the first inspection hole 81). The probe 60 is inserted into this third inspection hole 83 and set on the buried electric wire 17. The two-color light-emitting diode 76 was "yellow." The area between the third inspection hole 83 and the second inspection hole 82 was healthy, and the area between the third inspection hole 83 and the first inspection hole 81 was the next inspection target.

[0076] 10(d), a fourth inspection hole 84 is drilled in the middle of the next inspection target (between the third inspection hole 83 and the first inspection hole 81). The probe 60 is inserted into this fourth inspection hole 84 and set on the buried electric wire 17. The two-color light emitting diode 76 was “red.” The area between the fourth inspection hole 84 and the first inspection hole 81 was sound, and the disconnection location X was identified between the fourth inspection hole 84 and the third inspection hole 83.

[0077] In the "inspection method 3" described above, similarly to the "inspection method 1" shown in FIG. 8(a), the disconnection location X is identified by the change in color of the two-color light emitting diode 76. However, since the number of inspection holes 81 to 87 in Figure 8(a) is 7 and the number of inspection holes 81 to 84 in Figure 10(d) is 4, "Inspection Method 3" has the advantage over "Inspection Method 1" that the inspection time is expected to be shortened.

[0078] [Example of modification of buried electric wire inspection device] A modified example of the buried electric wire inspection device 40 described with reference to FIG. 3 will be described with reference to FIG. In this modified example, the probe 60 shown in Fig. 3 is replaced with a fifth clip 80. Since there are no other changes, in Fig. 11, the same components as those in Fig. 3 are designated by the same reference numerals as those in Fig. 3, and detailed descriptions of the common components will be omitted.

[0079] That is, as shown in FIG. 11, buried electric wire inspection device 40 comprises stationary part 41, movable part 59 carried by an inspector, and conductor 79. The movable part 59 consists of a fifth clip 80 electrically connected to the buried electric wire 17, a fourth harness 75 electrically connected to the fifth clip 80 and including a two-color light-emitting diode 76 that emits light of a different color, and a fourth clip 78 provided at the tip of the fourth harness 75.

[0080] The fifth clip 80 may be an inexpensive alligator clip, similar to the first alligator clip 46 as the first clip. In this modification, the relatively expensive probe 60 is replaced with the inexpensive fifth clip 80, so that the cost of the buried electric wire inspection device 40 can be further reduced.

[0081] The two-color light-emitting diode 76 may be replaced by two single-color light-emitting diodes. Specifically, the first color lamp 76a shown in FIG. 6(b) may be a single-color light-emitting diode that emits red light, and the second color lamp 76b may be a single-color light-emitting diode that emits yellow light. Two single-color light-emitting diodes are easier to obtain and less expensive than one two-color light-emitting diode 76. However, the two-color light-emitting diode 76 is recommended for ease of wiring.

[0082] Also, the two-color light emitting diode 76 may be replaced with a filament-type light bulb, but from the viewpoint of low power consumption, the two-color light emitting diode 76 is recommended.

[0083] Moreover, the first to fourth alligator clips 46, 48, 52, 78 and the fifth clip 80 may be changed to clips in which the spring is replaced with a screw (a clip different from the alligator clips). That is, as long as the first to fifth clips have a structure that allows them to be detachably engaged with the buried electric wire 17 or the conductor 79, the structure may be freely changed.

[0084] In addition, although the probe 60 and the fourth harness 75 are shown as separate parts in FIG. 3, they may be integrated into one part. [Industrial Applicability]

[0085] The present invention is suitable for use as an inspection device for inspecting buried electric cables laid in gardens or golf courses. [Explanation of symbols]

[0086] 17... buried electric wire, 17a... one end of the buried electric wire, 17b... other end of the buried electric wire, 20... ground, 40... buried electric wire inspection device, 41... stationary part, 42... first battery, 43... second battery, 44... battery box, 45... first harness, 46... first clip (first alligator clip), 47... second harness, 48... second clip (second alligator clip), 51... third harness, 52...third clip (third alligator clip), 59...moving part, 60...probe, 61...needle, 68...groove, 75...fourth harness, 76...two-color light-emitting diode, 76a...first color lamp, 76b...second color lamp, 78...fourth clip (fourth alligator clip), 79...conductor, 80...fifth clip, 81-87...first to seventh inspection holes, X...broken part.

Claims

1. A buried electric wire inspection device for inspecting buried electric wires buried in the ground, This buried electric wire inspection device comprises a stationary part to be placed at the end of the buried electric wire, a movable part carried by an inspector, and a conductor electrically connecting the movable part and the stationary part, the fixed portion comprises a battery box containing a first battery and a second battery, a first harness extending from the positive electrode of the first battery, a first clip provided at a tip of the first harness and electrically connected to one end of the buried electric wire, a second harness extending from the negative electrode of the second battery, a second clip provided at a tip of the second harness and electrically connected to the other end of the buried electric wire, a third harness extending from between the negative electrode of the first battery and the positive electrode of the second battery, and a third clip provided at a tip of the third harness, the movable portion comprises a probe having a groove for accommodating a part of the buried electric wire and a needle for contacting the buried electric wire, a fourth harness electrically connected to the needle and including a first color lamp and a second color lamp for emitting a color different from that of the first color lamp, and a fourth clip provided at a tip of the fourth harness; one end of the conductive wire is electrically connected to the third clip and the other end is electrically connected to the fourth clip; A buried electric wire inspection device characterized in that inspection holes are drilled in the ground at multiple locations along the buried electric wire, the probe is inserted into the inspection holes, and the needle is electrically connected to the buried electric wire, thereby lighting one of the first color lamp and the second color lamp, and when the inspection hole is changed, the first color lamp is changed to the second color lamp, or the second color lamp is changed to the first color lamp, thereby being used to find broken locations in the buried electric wire.

2. A buried electric wire inspection device for inspecting buried electric wires buried in the ground, This buried electric wire inspection device comprises a stationary part to be placed at the end of the buried electric wire, a movable part carried by an inspector, and a conductor electrically connecting the movable part and the stationary part, the fixed portion comprises a battery box containing a first battery and a second battery, a first harness extending from the positive electrode of the first battery, a first clip provided at a tip of the first harness and electrically connected to one end of the buried electric wire, a second harness extending from the negative electrode of the second battery, a second clip provided at a tip of the second harness and electrically connected to the other end of the buried electric wire, a third harness extending from between the negative electrode of the first battery and the positive electrode of the second battery, and a third clip provided at a tip of the third harness, the movable portion includes a fifth clip electrically connected to the buried electric wire, a fourth harness electrically connected to the fifth clip and including a first color lamp and a second color lamp emitting a color different from that of the first color lamp, and a fourth clip provided at a tip of the fourth harness; one end of the conductive wire is electrically connected to the third clip and the other end is electrically connected to the fourth clip; A buried electric wire inspection device characterized in that inspection holes are drilled in the ground at multiple locations along the buried electric wire, the fifth clip is inserted into the inspection holes and electrically connected to the buried electric wire, thereby lighting one of the first color lamp and the second color lamp, and when the inspection hole is changed, the first color lamp is changed to the second color lamp, or the second color lamp is changed to the first color lamp, thereby being used to find breaks in the buried electric wire.

3. The buried electric wire inspection device according to claim 1 or 2, 2. A buried electric wire inspection device, comprising: said first color lamp and said second color lamp, each of which is incorporated in a single two-color light-emitting diode.

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