Grounding nail driving device for insulated electric wires

Abstract

To provide a nailing device for grounding an electric wire, which is free from the risk of electric shock or injury due to failure in nailing and does not require a large amount of labor for the operation.SOLUTION: A nailing device 1 comprises: a frame 2 having a lower jaw 25 and an upper jaw 26; a nut member 3 supported by the upper jaw 26; a hydraulic cylinder 4 supported so as to be vertically adjustable with an outer peripheral threaded portion 41 screwed into the nut member; a piston rod 5 inserted into the hydraulic cylinder; and a nail holder 6 detachably attached to a lower end of the piston rod. The nail holder 6 is connected with a ground wire 8. The nail holder 6 holds a nail N with a head of itself caused to abut on the lower end of the piston rod 5 and with a tip of itself projecting downward. The nailing device can pierce a core wire C2 of an insulated electric wire C with the nail N by means of hydraulic pressure of the hydraulic cylinder 4, thereby enabling the insulated electric wire C to be grounded.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a device for driving a grounding nail into a coated electric wire in underground power distribution work or the like.

Background Art

[0002] Conventionally, as a grounding jig for a power cable, there is one disclosed in Patent Document 1. This grounding jig includes a hydraulic jack portion having a hydraulic jack body, a grounding needle attached to the tip of the hydraulic jack and driven into the power cable by its hydraulic operation, a grounding lead wire connected to the grounding needle, a jack fixing base on which the hydraulic jack is placed and installed so as to straddle the power cable, and a cable fixing tool attached to the jack fixing base for fixing the power cable.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention adopts the same basic structure as the above-mentioned conventional grounding jig for a power cable, and further adds a specific configuration to improve usability, and provides a device for driving a grounding nail into an electric wire without the risk of electric shock or injury due to misdriving and without requiring a large amount of labor for the work.

Means for Solving the Problems

[0005] In the following description, reference is made to the reference numerals in the accompanying drawings, but the present invention is not limited thereto. To solve the above problems, the present invention provides a grounding nail driving device 1 comprising a hook-shaped frame 2, a nut member 3 supported by the frame 2, a hydraulic cylinder 4 supported by the nut member 3, a piston rod 5 inserted into the hydraulic cylinder 4, and a nail holder 6 detachably attached to the lower end of the piston rod 5. The frame 2 comprises a lower jaw portion 25 that receives the insulated electric wire C to be grounded, and an upper jaw portion 26 that is continuous with the lower jaw portion 25 on one side of the insulated electric wire C received by the lower jaw portion 25 and faces the lower jaw portion 25 above the insulated electric wire C. The nut member 3 is fixed to the upper jaw portion 26 of the frame 2 and has a screw hole 31 whose central axis is directed toward the insulated electric wire C on the lower jaw portion 25. The hydraulic cylinder 4 is supported by the nut member 3 so as to be able to adjust its vertical position by screwing its outer thread portion 32 into the screw hole 31 of the nut member 3. The piston rod 5 is installed in the hydraulic cylinder 4, with its lower end protruding from the lower end of the hydraulic cylinder 4, and is capable of moving up and down within a predetermined stroke. The nail holder 6 is detachably attached to the lower end of the piston rod 5 that protrudes from the lower end of the hydraulic cylinder 4, and a grounding wire 8 is connected to it. The nail holder 6 is designed to hold the nail N by bringing the head of the nail into contact with the lower end of the piston rod 5 and having its tip protrude downward. The hydraulic pressure supplied from the hydraulic pump to the hydraulic cylinder 4 presses the nail N through the covering portion C1 of the insulated wire C until it reaches the core wire C2, thereby grounding the insulated wire C. [Effects of the Invention]

[0006] According to the present invention, a nail driving device can be provided that eliminates the risk of electric shock or injury due to missed nails when driving grounding nails into electric wires, and does not require a great deal of effort for the work. [Brief explanation of the drawing]

[0007] [Figure 1] This is a front view with a portion of the grounding nail driving device of the present invention cut out. [Figure 2] Figure 1 is a side view of the grounding nail driving device. [Figure 3] Figure 1 is a perspective view of the grounding nail driving device. [Figure 4]This is an enlarged view of section A in Figure 1. [Figure 5] Figure 1 is a front view of the grounding nail driving device in its shortest state. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described with reference to the drawings. The grounding nail driving device 1 comprises a hook-shaped frame 2, a nut member 3 supported by the frame 2, a hydraulic cylinder 4 supported by the nut member 3, a piston rod 5 inserted into the hydraulic cylinder 4, and a nail holder 6 detachably attached to the lower end of the piston rod 5.

[0009] Frame 2 is constructed by joining a pair of parallel frame plates 21 via collars 22 using bolts and nuts 23. Frame 2 comprises a mandibular portion 25 and an upper portion 26 that is continuous with the mandibular portion 25 on one side. The insulated wire C to be grounded is placed on the arc-shaped support surface 25a of the mandibular portion 25. The upper portion 26 faces the mandibular portion 25 above the insulated wire C on the mandibular portion 25, and the other side of Frame 2 is open to allow the insulated wire C to be placed on the mandibular portion 25. The support surface 25a is not limited to an arc shape, and it is desirable that it be a shape that makes it easy to position the center of the insulated wire C below the central axis of the piston rod 5.

[0010] The nut member 3 is fixed between the frame plates 21 of the upper jaw portion 26 of the frame 2. The nut member 3 has a screw hole 31 with its central axis oriented towards the center of the insulated wire C.

[0011] The hydraulic cylinder 4 has a threaded portion 41 on its outer circumference and a lock nut 42 that screws onto it, and a handle 43 for rotational operation on its upper part. The hydraulic cylinder is supported by the nut member 3 by screwing the outer threaded portion 41 into the threaded hole 31 of the nut member 3 and aligning its central axis with the nut member 3. The lock nut 42 is positioned above the nut member 3 and, after adjusting the vertical position of the hydraulic cylinder 4 relative to the frame 2, is tightened so as to abut against the nut member 3. The hydraulic cylinder 4 is connected to a hydraulic pump (not shown) via a hydraulic hose (not shown) connected to a coupler 44, and oil is supplied and discharged under the control of this hydraulic pump.

[0012] The piston rod 5 is inserted into the hydraulic cylinder 4 via a return spring 7, with its central axis aligned with the hydraulic cylinder 4, and is vertically movable so that its lower end protrudes from the lower end of the hydraulic cylinder 4 at a predetermined stroke. An annular groove 51 is formed on the outer circumference of the tip of the piston rod 5.

[0013] The nail holder 6 is generally ring-shaped and has a ball plunger 61 at its upper end. The nail holder 6 fits onto the outer circumference of the lower end of the piston rod 5 that protrudes from the lower end of the hydraulic cylinder 4, and the ball plunger 61 is detachably attached to the piston rod 5 by engaging and disengaging it from the annular groove 51. The nail holder 6 has a large-diameter holding space 64 on its inner upper part and a small-diameter through hole 65 on its lower part. The head of the nail N is held in the holding space 64, and the lower part protrudes downward through the through hole 65 along the central axis of the piston rod 5. The head of the nail N abuts against the lower end of the piston rod 5 within the holding space 64. In the illustrated embodiment, a commercially available concrete nail is used as the nail N.

[0014] A wing bolt 8 for connecting the terminal of the grounding wire 9 is screwed onto the side of the nail holder 6. Thus, the nail holder 6 is electrically grounded via the grounding wire 9.

[0015] When performing grounding work, attach the nail N to the nail holder 6 and connect the terminal of the grounding wire 9 to the side with the wing bolt 8. Fit this nail holder 6 to the tip of the piston rod 5 and engage and fix the ball plunger 61 in the annular groove 51. Next, take in the covered wire C onto the lower jaw portion 25 of the frame 2. The covered wire C is arranged on the placing and receiving surface 25a at a position approximately directly below the nail N. By grasping the handle 43 and rotating the hydraulic cylinder 4, lower the hydraulic cylinder 4 with respect to the frame 2, place the tip of the nail N against the covered wire C for positioning, and tighten the lock nut 42 to fix the hydraulic cylinder 4. Connect a hydraulic hose to the coupler 43, operate the hydraulic pump to send oil to the hydraulic cylinder 4, lower the piston rod 5 by a predetermined distance, and drive the nail N into the covered wire C. This completes the grounding of the covered wire C.

[0016] When the piston rod 5 is raised and returned by operating the hydraulic pump or automatically releasing the hydraulic pressure, the engaging force between the ball plunger 61 and the piston rod 5 yields to the pulling resistance of the nail N against the covered wire C, the engagement between the ball plunger 61 and the piston rod 5 is automatically disengaged, and the nail holder 6 remains on the covered wire C. After completion of the cutting work on the covered wire C, remove the nail N together with the nail holder 6 with a burr or the like, separate them, and recover them.

[0017] Note that as a means for automatically leaving the nail holder 6 on the covered wire C, that is, an engaging means capable of setting the engaging force between the nail holder 6 and the piston rod 5 to be smaller than the pulling resistance of the nail N against the covered wire C, engagement by magnetic force and various other modifications are possible.

[0018] By using the nail driving device 1 for grounding, in the work of driving the grounding nail N, no great labor is required, and since the operator does not come into contact with the core wire C2 of the covered wire C, there is no risk of electric shock, and there is also no danger of injury due to misdriving.

Explanation of Signs

[0019] 1 Nail driving device 2 Frame 21 Frame plate 22 colors 23 bolts and nuts 24 arc-shaped recess 25 lower jaw part 25a mounting surface 26 upper jaw part 3 nut member 31 threaded hole 4 hydraulic cylinder 41 outer peripheral thread part 42 lock nut 43 handle 44 coupler 5 piston rod 51 annular groove 6 nail holder 61 ball plunger 64 holding space 65 through hole 7 return spring 8 wing bolt 9 ground wire

Claims

1. A frame comprising a mandible portion that supports an insulated electric wire to be grounded, and an upper mandible portion that is continuous with the mandible portion on one side of the insulated electric wire supported by the mandible portion and faces the mandible portion above the insulated electric wire, A nut member fixed to the upper jaw portion of the frame and having a screw hole with its central axis directed toward the insulated electric wire on the lower jaw portion, The outer threaded portion is screwed into the threaded hole of the nut member, and a hydraulic cylinder is supported by the nut member so as to be able to adjust its vertical position. A piston rod is installed in the aforementioned hydraulic cylinder, with its lower end protruding from the lower end of the hydraulic cylinder, and is capable of moving up and down within a predetermined stroke, The system comprises a nail holder that is detachably attached to the lower end of the piston rod and to which a grounding wire is connected, The nail holder is provided to hold the nail by bringing the head of the nail into contact with the lower end of the piston rod and having the tip protrude downward. A nailing device for grounding insulated electric wires, characterized in that hydraulic pressure supplied from a hydraulic pump to the hydraulic cylinder is used to press-drive the nail through the insulated portion of the insulated electric wire until it reaches the core wire.

2. The grounding nail driving device for insulated electric wires according to claim 1, further comprising a lock nut located above the nut member and screwed onto the outer threaded portion of the hydraulic cylinder, wherein the vertical position of the hydraulic cylinder relative to the frame is adjustable.

3. The piston rod and the nail holder are detachably connected by mutual engagement means having an engagement force smaller than the resistance force of the nail being pulled out of the insulated wire. The insulated wire grounding nail driving device according to claim 1 or 2, characterized in that when the piston rod returns to its original position, the nail holder automatically detaches from the piston rod and remains on the insulated wire together with the nail.

4. The grounding nail driving device for insulated electric wires according to claim 3, characterized in that the means for mutual engagement between the piston rod and the nail holder comprises an annular groove formed on the outer circumference of the tip of the piston rod and a ball plunger provided on the nail holder so as to be detachably engaged with the annular groove.

5. The nailing device for grounding insulated electric wires according to claim 1 or 2, characterized in that a wing bolt for securing the grounding wire is screwed onto the outer circumference of the nail holder.

6. The aforementioned frame is constructed by joining a pair of parallel frame plates with bolts via collars, The grounding nail driving device for insulated electric wires according to claim 1 or 2, characterized in that the nut member is fixed between the upper parts of the pair of frame plate materials.

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