JP2011142754A - Grounding hook - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out attachment of an opening/closing hook with a proper tightening force. <P>SOLUTION: A grounding hook includes: an electrically insulating operation bar; a head metal piece having an opening/closing hook opened and closed by turning the operation bar around its axis, an earth metal piece fitted to a given earth spot; and an earth cable electrically for connecting the head metal piece to the earth metal piece. Between the front end of the operation bar and the head metal piece, a torque transmitting mechanism is disposed which transmits a torque to the head metal piece when the torque given to the operation bar is equal to or less than a preset torque, but makes idling turns and does not transmit torque to the head metal piece, when the torque exceeds the preset torque. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ground hook.

  When working on the electrical equipment, the electrical equipment is grounded by a ground hook from the viewpoint of preventing the inflow of electricity and ensuring the safety of the work. In this earth hook, a head hardware attached to an electric wire or the like is provided with an opening / closing hook that is opened and closed by a circumferential rotation operation with respect to an operation rod, as in a voltage detection probe disclosed in Patent Document 1, for example.

JP 2001-91551 A

  In this earth hook, there are individual differences in the tightening force (rotational torque with respect to the operating rod) at the time of attachment, and there are the following problems.

  First, as a problem caused by overtightening, the attachment location may be damaged or the opening / closing hook may be deformed. In addition, there is a problem that it takes time and effort to remove it if it is tightened too much. Second, as a problem due to insufficient tightening, the attached earth hook may come off. Thirdly, since it is difficult to grasp the proper tightening force, there is a problem that it is necessary to perform confirmation work for confirming whether the tightening is properly performed, and it takes time.

  This invention is made | formed in view of such a situation, The objective is to perform attachment of an opening-and-closing hook with appropriate tightening force.

In order to achieve the above object, the present invention provides an operation rod having electrical insulation, a head hardware provided with an opening / closing hook that is opened and closed by a rotational operation around an axis with respect to the operation rod, and a grounding attached to a predetermined grounding location. A ground hook having a hardware and a ground wire that electrically connects the head hardware and the ground hardware,
When the rotational torque applied to the operating rod is less than or equal to a set torque, the rotational force is transmitted to the head hardware when interposed between the tip of the operating rod and the head hardware. When it exceeds, it has a torque transmission mechanism that idles and does not transmit the rotational force to the head hardware.

  According to the present invention, when the rotational torque applied to the operating rod by the torque transmission mechanism exceeds the set torque, the rotational force is not transmitted to the head hardware. By rotating the operating rod with the force (torque), the opening / closing hook can be attached with an appropriate tightening force.

The ground hook preferably includes a switch that is turned on when the torque transmission mechanism is idling and a notification unit that informs that idling has occurred when the switch is turned on.
If comprised in this way, even if it is the situation where the operating rod is long and it is difficult for the feeling of idling to be transmitted through the operating rod, the operator can recognize that idling has occurred. Thereby, working efficiency can be improved.

In the ground hook, the notification unit notifies that idle rotation has occurred due to at least one of light and sound, and is provided at a rear end portion of the operation rod opposite to the tip end. preferable.
If comprised in this way, the alerting | reporting by an alerting | reporting part can be confirmed with a sound or light in the place near an operator. Thereby, working efficiency can be improved further.

  According to the present invention, the opening / closing hook can be attached with an appropriate tightening force.

It is a figure explaining the whole earth hook of this embodiment. It is a figure explaining a head metal fitting. It is a figure explaining a torque transmission mechanism, and has shown the state adjusted to predetermined torque. It is a figure explaining a torque transmission mechanism, and has shown the state adjusted to the torque stronger than the state of FIG. It is a figure explaining embodiment which provided the alerting | reporting part.

=== First Embodiment ===
<Overall configuration of ground hook>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The ground hook 1 shown in FIG. 1 includes an operation rod 10, a head hardware 20, a torque transmission mechanism 30, a ground wire 40, and a ground hardware 50.

  The operating rod 10 is a portion that is held by an operator when the ground hook 1 is attached, and is constituted by a pipe-like member having a diameter of 30 mm to 40 mm and an overall length of about 2 m to 6 m. The operation rod 10 is made of a material having electrical insulation. For example, a resin pipe made of an epoxy resin is used. A torque transmission mechanism 30 is provided at the distal end portion of the operation rod 10, and the head hardware 20 is attached via the torque transmission mechanism 30.

In addition, when the operating rod 10 has a length exceeding 3 m, it is divided into a plurality of pieces. This is to ensure convenience in carrying.
The head hardware 20 is a part that is attached to an attachment fitting, an electric wire terminal, an electric wire or the like attached to the device, and has a main body 21 and an opening / closing hook 22.

  As shown in detail in FIG. 2, the main body 21 includes a rotating rod 23, an intermediate gear 24, and a metal cover 25. The rotating rod 23 is housed in a rotatable state in the metal cover 25, and rotates by the rotational force from the torque transmission mechanism 30. A screw thread 23 a is formed at the tip of the rotating rod 23. The intermediate gear 24 is also housed in the metal cover 25 in a rotatable state. The intermediate gear 24 meshes with a screw thread 23 a provided on the rotating rod 23 and rotates as the rotating rod 23 rotates. That is, the screw thread 23a and the intermediate gear 24 constitute a cylindrical worm gear. Therefore, the rotation of the rotating rod 23 is transmitted to the intermediate gear 24 in a state converted into the orthogonal direction. The intermediate gear 24 meshes with a sector gear (fan gear) 22 a provided at the root of the opening / closing hook 22.

  The opening / closing hook 22 is a lever-shaped part made of metal. And the root part is accommodated in the metal cover 25, and is attached in the state which can be rotated centering on the metal rotating shaft 22b. A portion on the tip side of the rotation shaft 22b is exposed to the outside of the metal cover 25, and is moved in a direction approaching and separating from the metal cover 25. As described above, since the sector gear 22 a meshing with the intermediate gear 24 is provided at the root portion of the opening / closing hook 22, the opening / closing hook 22 moves against the metal cover 25 as the rotating rod 23 rotates. Move closer or farther away. That is, it opens and closes around the rotation shaft 22b. In the present embodiment, the opening / closing hook 22 rotates in the closing direction when the operating rod 10 is rotated clockwise (clockwise), and is opened when the operating rod 10 is rotated counterclockwise (counterclockwise). Rotate in the direction. An object to be grounded (electric wire W in FIG. 2) is disposed between the opening / closing hook 22 and the metal cover 25 in the closed state.

  The torque transmission mechanism 30 transmits the rotational force to the head hardware 20 when the rotational torque applied to the operating rod 10 is equal to or less than the set torque, and idles when the rotational torque exceeds the set torque. This is a part that prevents the rotational force from being transmitted to the head hardware 20. The torque transmission mechanism 30 will be described later.

  The ground wire 40 is a member that electrically connects the head hardware 20 and the ground hardware 50. The ground wire 40 is composed of a metal wire having a diameter of about 6 mm to 10 mm and a length of about several meters to several tens of meters, and a resin tube covering the metal wire. As shown in FIG. 2, the head hardware 20 is connected to the back surface of the metal cover 25 on the side opposite to the opening / closing hook 22 by a mounting bracket 26. The ground wire 40 causes the head hardware 20 and the ground hardware 50 to conduct and have the same potential.

  The grounding hardware 50 is a member for electrically connecting the ground wire 40 to a predetermined grounding location. In the present embodiment, as shown in FIG. 1, a clamp-type grounding hardware 50 having a metal U-shaped frame 51 and a screw 52 is illustrated. The grounding hardware 50 is attached to, for example, a driving grounding rod (not shown) driven into the ground. The ground metal 50 is not limited to the clamp type, and various types such as a clip type can be used.

<Configuration of torque transmission mechanism 30>
Next, the torque transmission mechanism 30 will be described. Here, FIG. 3A is a partially enlarged view of the torque transmission mechanism 30 when the rotational torque is set to 2.5 N · m. FIG. 3B is a partial cross-sectional view illustrating the internal structure. FIG. 3C is a view for explaining the position of the recess 31e in which the pressing pin 32 and the rear end portion 32a of the pressing pin 32 are fitted. FIG. 4A is a partially enlarged view of the torque transmission mechanism 30 when the rotational torque is set to 4 N · m. FIG. 4B is a partial cross-sectional view illustrating the internal structure. In FIGS. 3A and 3B and FIGS. 4A and 4B, the left side corresponds to the front end side, and the right side corresponds to the rear end side.

  As shown in these drawings, the torque transmission mechanism 30 includes a transmission part 31, a pressing pin 32, a spring 33, and an outer cylinder 34.

  The transmission unit 31 is a cylindrical member connected to the rotary rod 23 of the head hardware 20, and is movable in the longitudinal direction of the operation rod 10 on the inner peripheral side at the distal end portion of the operation rod 10. It is attached in a rotatable state. The intermediate portion 31b in the axial direction of the transmission portion 31 is provided slightly thinner than the other portions 31a and 31c. A scale indicating the set torque is formed on the surface of the intermediate portion 31b. For convenience, in the following description, a portion on the front end side with respect to the intermediate portion 31b is referred to as a front end portion 31a, and a portion on the rear end side (opposite side to the front end side) with respect to the intermediate portion 31b is referred to as a rear end portion 31c.

  The rear end portion 31c of the transmission part 31 is configured to be slightly thicker than the intermediate portion 31b. For this reason, a ring-shaped step surface 31d is formed between the peripheral surface of the rear end portion 31c and the peripheral surface of the intermediate portion 31b in a direction orthogonal to these peripheral surfaces. And in this level | step difference surface 31d, the hemispherical recessed part 31e in which the rear-end part of the press pin 32 fits is formed in the predetermined space | interval. In this embodiment, 16 concave portions 31e are formed at intervals of 22.5 degrees. Further, the distal end portion 31 a of the transmission portion 31 is connected to the rotating rod 23 of the head hardware 20 through the inside of the outer cylinder 34.

  The pressing pin 32 is inserted into the pin hole 11 provided at the distal end portion of the operating rod 10 in a state where the pressing pin 32 can advance and retract. The rear end portion 32a of the pressing pin 32 is formed in a hemispherical shape, and is disposed so as to fit into the recess 31e as described above. Therefore, in this embodiment, 16 pressing pins 32 are provided. The spring 33 is inserted into each of the plurality of pin holes 11 and presses the corresponding pressing pin 32 to the rear end side. That is, the rear end portion 32a of the pressing pin 32 is pressed against the concave portion 31e.

  In the normal state, the tip side portion of the pressing pin 32 is fitted in the pin hole 11. For this reason, if the pressing force by the spring 33 is sufficiently strong, the rotational force (torque) applied to the operating rod 10 is transmitted to the transmitting portion 31 via the pressing pin 32 and the recess 31e. And since the transmission part 31 is connected to the rotation rod 23, the rotation rod 23 rotates with the rotational force given to the operation rod 10, and the opening-and-closing hook 22 is opened and closed. That is, the rotational force of the operating rod 10 is transmitted to the head hardware 20.

  On the other hand, when the pressing force by the spring 33 is insufficient with respect to the rotational force applied to the operating rod 10, the pressing pin 32 is pushed back in the distal direction along the curved surface of the recess 31e and is released from the recess 31e. In this case, the operating rod 10 is idle with respect to the transmission portion 31, and the rotational force applied to the operating rod 10 is not transmitted to the rotating rod 23, and the opening / closing hook 22 is not opened / closed. That is, the rotational force of the operating rod 10 is not transmitted to the head hardware 20. Then, by changing the pressing force of the pressing pin 32 by the spring 33, it is possible to set the rotational force until idling.

  The outer cylinder 34 is a member for moving the operating rod 10 and the transmission portion 31 relative to the axial direction of the operating rod 10, and is provided in a state in which it can advance and retreat relative to the head hardware 20. . The outer cylinder 34 moves forward and backward with respect to the head hardware 20, thereby moving the operating rod 10 toward the rear end with respect to the transmission portion 31 or moving it toward the front end. As can be seen from a comparison between FIG. 3 and FIG. 4, when the operating rod 10 is moved to the rear end side, the degree of compression of the spring 33 becomes stronger, and the required torque until idling increases. The outer cylinder 34 is provided with a window 34a for allowing the scale provided on the intermediate portion 31b of the transmission portion 31 to be visually recognized from the outside. Therefore, the operator can arbitrarily set the torque (set torque) until idling by determining the feed amount of the outer cylinder 34 while visually checking the scale. For example, in the example of FIG. 3, the set torque is 2.5 N · m, and in the example of FIG. 4, the set torque is 4.0 N · m.

<How to use the ground hook 1>
Next, the usage method of the ground hook 1 in this embodiment is demonstrated.
In attaching the ground hook 1, the operator sets a tightening torque. That is, the torque until idling with the transmission unit 31 is set. As described above, the tightening torque is set by adjusting the feed amount of the outer cylinder 34 included in the torque transmission mechanism 30. When the tightening torque is set, the opening / closing hook 22 is opened. For example, the opening / closing hook 22 is opened by rotating the operating rod 10 in the circumferential direction while holding the head hardware 20 by hand.

  When the opening / closing hook 22 is opened, the operation rod 10 is added as necessary. As described above, since one operating rod 10 is 3 m or less, when the object to be grounded is farther than 3 m, the operating rod 10 is added according to the distance. Thereafter, the grounding hardware 50 is attached to a predetermined grounding location. For example, it is attached to a driving grounding rod driven into the ground.

  When the grounding hardware 50 is attached, the head hardware 20 is hooked on the object to be grounded. For example, the head hardware 20 is hooked on the electric wire. At this time, the operator holds the rear end portion of the operation rod 10 and lifts the front end portion upward. Then, the head hardware 20 is moved so that the electric wire W is positioned between the opening / closing hook 22 and the main body 21.

  If the electric wire is positioned between the opening / closing hook 22 and the main body 21, the operator rotates the operation rod 10 in the right direction. At this time, if the rotational force with respect to the operating rod 10 is equal to or less than the set torque, the rotational force of the operating rod 10 is transmitted to the rotating rod 23 of the head hardware 20 via the transmission unit 31. Since there is an electric wire W between the opening / closing hook 22 and the main body portion 21, the movement of the head hardware 20 in the rotation direction is restricted by the electric wire W, and the operation rod 10 rotates separately from the head hardware 20. . As a result, the open / close hook 22 is moved in the closing direction.

  When the opening / closing hook 22 is closed, the operator stops the rotation of the operation rod 10. As described above, in the ground hook 1 of the present embodiment, when a rotational force that is equal to or greater than the set torque is applied from the operation rod 10, the pressing pin 32 moves in the return direction, and between the transmission portion 31 and the operation rod 10. Idling occurs. Thereby, it is possible to prevent a problem that the operator closes the opening / closing hook 22 with an excessive force by rotating the operation rod 10 strongly. That is, the opening / closing hook can be attached with an appropriate tightening force.

  In addition, the opening / closing hook 22 is in a closed state corresponding to the set torque by rotating the operating rod 10 until it idles. For this reason, it is possible to prevent a problem that the opening / closing hook 22 is not sufficiently closed and detached, and the confirmation work after the attachment can be omitted.

=== Second Embodiment ===
In the first embodiment described above, the opening / closing hook 22 is in a desired closing state by rotating the operating rod 10 strongly until idling occurs. Here, when the length of the operation rod 10 is about 3 m or 6 m, there may be a case where the idling cannot be felt by the touch of the hand. In particular, it is more difficult to feel idling when wearing insulating gloves.

  The second embodiment has been made in view of such circumstances, and has a feature in that an operator can be notified that idling has occurred. This will be described below.

  As shown in FIG. 5A, the ground hook 1 of the second embodiment includes a switch 61, a control unit 62, a speaker 63, an LED 64, and a power source 65.

  The switch 61 is a part that detects idling between the transmission unit 31 (see FIG. 3 and the like) and the operation rod 10. In the present embodiment, as shown in FIG. 5B, the contact portion 61 a attached to the outer peripheral surface of the rear end portion 31 c of the transmission portion 31 and the inner peripheral surface of the distal end portion 31 a of the operation rod 10 are attached. And a conductor pair 61b. The contact portion 61a is made of a thin metal plate, and a plurality of contact portions 61a are provided at positions overlapping the conductor pair 61b in the longitudinal direction of the operation rod 10. On the other hand, the conductor pair 61b is constituted by two metal plates formed in a strip shape, and is spaced in the inner circumferential direction of the operation rod 10 (that is, the rotation direction of the transmission portion 31) smaller than the width of the contact portion 61a. Is provided. Then, in the idling state until the pressing pin 32 is detached from the recessed portion 31e and fits into the adjacent recessed portion 31e, the contact portion 61a is provided at a position covering the conductor pair 61b, as shown by a one-dot chain line in FIG. Yes. Thereby, whenever the transmission part 31 and the operating rod 10 idle | swivel and the contact part 61a passes the conductor pair 61b, the conductor pair 61b will be in a conduction | electrical_connection state. For this reason, it is possible to detect that idling has occurred by detecting a change in the electrical state between the conductor pair 61b (for example, a change in voltage, current, or resistance value). The conductor pair 61b and the control unit 62 are electrically connected through the wiring member 66.

  The control unit 62 operates by receiving power from the power supply 65 and controls the speaker 63 and the LED 64 based on a slip detection signal (change in voltage or current) obtained from the switch 61. The control unit 62 is configured by, for example, a PIC (Peripheral Interface Controller), and when the detection signal from the switch 61 changes to indicate idling, the control unit 62 outputs a beep sound from the speaker 63 or the LED 64 over a predetermined period. Or turn on. The speaker 63 is provided at the rear end portion 31 c of the operation rod 10 and outputs a beep sound according to a beep signal output from the control unit 62. The LED 64 is also provided at the rear end portion 31 c of the operation rod 10 and lights up according to a control signal output from the control unit 62.

  In the ground hook 1 of the second embodiment, when the transmission unit 31 and the operation rod 10 are idle, the switch 61 detects the idle rotation, and the control unit 62 controls the speaker 63 and the LED 64. Then, the operator can recognize that idling has occurred by confirming the beep sound from the speaker 63 and the lighting of the LED 64. And since the speaker 63 and LED64 are provided in the rear-end part 31c of the operating rod 10 which an operator hold | grips at the time of work, it can be made to recognize reliably that the operator slipped. Thereby, it is not necessary to idle the operating rod 10 and the workability can be improved. Further, since the speaker 63, the LED 64, the control unit 62, and the power source 65 are built in the operation rod 10, it is difficult to disturb the work. In this respect, workability can be improved.

=== Other Embodiments ===
The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The present invention is changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

  For example, in the above-described embodiment, the head hardware 20 and the operation rod 10 are integrally provided via the torque transmission mechanism 30, but the present invention is not limited to this configuration. That is, the head hardware 20 and the operation rod 10 may be configured to be detachable.

  In this case, the torque transmission mechanism 30 may be provided on the operation rod 10 side, or may be provided on the head hardware 20 side. And when it provides in the operating rod 10 side, while being able to simplify the structure of the head metal fitting 20, it can reduce in weight. On the other hand, when it is provided on the head hardware 20 side, the weight of the tip of the operation rod 10 becomes light, so that the operation becomes easy and the workability can be improved.

  In addition, the shape of the opening / closing hook 22 can be appropriately selected according to what is to be grounded.

DESCRIPTION OF SYMBOLS 1 Ground hook, 10 Operation rod, 11 Pin hole, 20 Head hardware, 21 Main part, 22 Opening / closing hook, 22a Sector gear, 22b Rotating shaft, 23 Rotating rod, 23a Thread, 24 Intermediate gear, 25 Metal cover, 26 Mounting bracket, 30 Torque transmission mechanism, 31 Transmission portion, 31a Front end portion, 31b Intermediate portion, 31c Rear end portion, 31d Stepped surface, 31e Recessed portion, 32 Press pin, 32a Rear end portion, 33 Spring, 34 Outer tube, 34a Window, 40 Earth wire, 50 Ground metal, 51 U-shaped frame, 52 Screw, 61 Switch, 61a Contact part, 61b Conductor pair, 62 Control part, 63 Speaker, 64 LED, 65 Power supply, 66 Wiring member, W wire

Claims (3)

An operating rod having electrical insulation;
A head hardware comprising an opening and closing hook that is opened and closed by a rotating operation around an axis with respect to the operation rod;
A grounding hardware attached to a predetermined grounding location;
An earth hook having an earth wire for electrically connecting the head hardware and the ground hardware,
When the rotational torque applied to the operating rod is less than or equal to a set torque, the rotational force is transmitted to the head hardware when interposed between the tip of the operating rod and the head hardware. An earth hook, characterized by having a torque transmission mechanism that idles when exceeding and does not transmit rotational force to the head hardware. A switch that is turned on when the torque transmission mechanism is idle,
The ground hook according to claim 1, further comprising a notification unit that notifies that idling has occurred when the switch is turned on.   The informing unit is for informing that at least one of light and sound has caused idling, and is provided at a rear end portion of the operation rod opposite to the front end. 2. The earth hook according to 2.

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