JP2010213395A - Grounding device for electric civil engineering machines - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a grounding structure that is simple and yet withstands thumping vibration in an electric civil engineering machine, such as concrete vibrator. <P>SOLUTION: A grounding device for electric civil engineering machines is constructed by providing a ground wire 7 in an electric wire bundle 6 obtained by bundling multiple electric wires 5 protected with an electric wire protecting member 4 of elastic insulating material, installing a contact piece 82 of a ground terminal 8 on the circumference of the electric wire bundle 6, providing a connecting piece 81 so that it connects to one end of the contact piece 82, connecting the connecting piece 81 to the ground wire 7, inserting the electric wire bundle 6 with the ground terminal 8 attached thereto into an electric wire insertion hole 21 having an inner wall with conductivity to the casing of a motor, and sandwiching the contact piece 82 of the ground terminal 8 between the outer circumference of the electric wire bundle 6 and the inner wall of the electric wire insertion hole 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a grounding structure for an electric civil engineering work machine such as a concrete vibrator.

  Conventionally, many electric civil engineering machines such as concrete vibrators do not have a ground structure.

  In order to enhance safety, it is preferable to provide an earth structure for electric civil engineering machines such as concrete vibrators. However, conventional electric civil engineering machines such as concrete vibrators have an earth structure with excellent assembly and vibration resistance. There is nothing with.

As a general grounding structure, for example, it is conceivable to attach a grounding wire to a casing of an electric motor by screwing like a grounding structure disclosed in Japanese Patent Application Laid-Open No. 2001-245462.
However, this method necessitates a significant structural change for attaching the ground, which is not preferable from the viewpoints of miniaturization, weight reduction, and ease of handling.
In addition, the electric civil engineering work machine often involves vibration, and when the ground connection is fixed with a screw, the screw may loosen and a connection failure may occur. To prevent this, it is conceivable to use a screw loosening prevention agent or to weld the ground wire directly instead of fixing the screw, but the screw loosening prevention agent is inferior in conductivity and is not suitable for ground connection. It takes time to connect.
JP 2001-245462 A

  An object of the present invention is to obtain an earth structure that can withstand severe vibrations with a simple structure in an electric civil engineering work machine such as a concrete vibrator.

In the grounding device for the electric civil engineering work machine according to the present invention, a ground wire is disposed inside a bundle of wires formed by bundling a plurality of wires protected by a wire protection member made of an elastic insulating material, and a ground terminal is provided on the outer periphery of the wire bundle. A connecting piece is connected to one end of the contact piece, the connecting piece is connected to the ground wire, and an inner wall that connects the electric wire bundle with the ground terminal connected to the casing of the motor is provided. The contact piece of the ground terminal is sandwiched between the outer periphery of the wire bundle and the inner wall of the wire insertion port.
The electric wire protection member is a concept including not only a member for further protecting an electric wire covered with an elastic resin but also a member for directly protecting a bare electric wire such as a copper wire.
As the ground wire, use an electric wire such as copper wire (which may or may not be covered with an insulator) as long as it is arranged inside the bundle of wires bundled with multiple wires protected by the wire protection member. It is conceivable that the wire bundle is interposed between a plurality of wire protection members constituting the wire bundle.
The ground terminal has a shape in which the contact piece can be placed on the outer periphery of the wire bundle, and the connection piece is connected to the earth terminal and connected to the ground wire inside the wire bundle. The contact piece is preferably a ring-shaped metal piece formed in an annular shape, but a wire can also be used. Moreover, what is necessary is just to fit in an electric wire bundle, Comprising: About the outer periphery 2/3 of an electric wire bundle may be covered.
The electric wire insertion port is a hole for inserting an electric wire for supplying electric power to the electric civil engineering work machine, and may have an inner wall electrically connected to a casing of an electric motor such as a motor. It is not necessary to be provided in the body itself.

  The ground wire and the ground terminal need only be connected within the space formed inside the wire bundle, but in order to protect this connection portion, the connection portion between the ground wire and the ground terminal is formed by a plurality of wire protection members. It is preferable to hold (claim 2).

  A rubber ring may be attached to the wire insertion port opening side of the wire bundle inserted into the wire insertion port.

  According to this invention, the ground wire is disposed inside the bundle of wires bundled with a plurality of wires protected by a wire protection member made of an elastic insulating material, and the ground terminal is covered with the connection piece on the outer periphery of the bundle of wires. The attached wire bundle is inserted into the wire insertion port with the inner wall that is connected to the casing of the motor, and the ground terminal contact piece is sandwiched between the outer periphery of the wire bundle and the inner wall of the wire insertion port, so the ground terminal and the wire insertion are surely The inner wall of the mouth can be brought into contact. That is, since the wire protection member constituting the wire bundle is made of an elastic insulating material, the contact piece of the ground terminal attached to the outer periphery of the wire bundle is pressed against the inner wall of the wire insertion port by the elastic force of the wire protection member. Thus, the ground terminal and the inner wall of the wire insertion port can be reliably brought into contact with each other.

  According to invention of Claim 2, since the connection part of the earth wire and earth terminal currently connected inside the wire bundle is hold | maintained by the several electric wire protection member, the connection part was comprised with the elastic insulation material. It is protected by the electric wire protection member, and the durability against vibration of the electric civil engineering work machine can be improved.

  According to the invention of claim 3, since the rubber ring is attached to the wire insertion port opening side of the wire bundle inserted into the wire insertion port, when the ground wire is pulled backward (power supply side) The rearward movement of the terminal contact piece is restricted by the rubber ring, and the contact state between the ground terminal contact piece and the inner wall of the wire insertion port can be prevented from being released.

FIG. 1 is a longitudinal sectional view showing an outline of a concrete vibrator having an earth structure of the present invention.
The concrete vibrator main body 1 is connected to a hose 3 through a hose joint 2. Inside the hose 3, a power supply electric wire 5 protected by an electric wire protection member 4 made of an elastic insulating material such as rubber is arranged in a bundle of three electric wires 6.
The electric wire bundle 6 will be described with reference to FIG. 2. The electric wire protection member 4 has a substantially sectoral cross section, and a hole for passing the electric wire 5 is formed in the vicinity of the center thereof. Is inserted. The three electric wire protection members 4 through which the electric wires 5 are inserted are concentrically arranged and bundled to form an electric wire bundle 6.
A ground wire 7 is disposed in a cavity formed near the center of the wire bundle 6, and a ground terminal 8 is connected to the tip of the ground wire 7.

The ground terminal 8 is configured by bending a belt-shaped elastic conductive material, and the wire bundle passes through between the contact piece 82 fitted to the outer periphery of the wire bundle and the adjacent wire protection member 4 connected to the contact piece 82. 6 and a ground wire connecting piece 81 extending into the interior. The ground wire 7 is connected to the inside of the ground wire connecting piece 81. The ground wire connection portion 81 is elastically held by the surrounding electric wire holding member 4 in a state where it is connected to the ground wire 7, and disconnection due to vibration or the like is prevented.
The contact piece 82 of the ground terminal 8 is attached to the wire bundle 6 so as to cover the outer periphery of the wire bundle 6.

The wire bundle 6 to which the ground terminal 8 is attached is fitted into the wire insertion port 21 of the hose joint 2. And the inner wall of the electric wire insertion port 21 is connected with the casing of the motor charging part built in the vibrator main body.
The diameter of the electric wire bundle 6 formed by bundling a plurality of electric wires 5 protected by the electric wire protection member 4 is the same as or slightly larger than the inner diameter of the electric wire insertion port 21. The wire bundle 6 can be easily inserted into the wire insertion port 21 by forming the taper shape so that the diameter on the opening side increases.
Since the inserted electric wire bundle 6 is in the inserted state, the elastic force of the electric wire protection member 4 works in the outer peripheral direction of the electric wire bundle 6, so that the contact piece 82 of the ground terminal 8 extends in the direction of the inner wall of the electric wire insertion port 21. When pressed, the contact piece 82 is sandwiched between the outer periphery of the wire bundle 6 and the inner wall of the wire insertion port 21.

  A rubber ring 9 is attached to the wire insertion port opening side of the wire bundle 6 inserted into the wire insertion port 21. The connection between the concrete vibrator main body 1 and the hose 3 is easily tensioned during handling, and the ground wire 7 is easily pulled backward (on the power supply side), but by attaching the rubber ring 9, the ground terminal 8 moves backward. The contact state between the contact piece 82 of the ground terminal and the inner wall of the wire insertion port 21 is maintained.

  Reference numeral 10 in the drawing is a hose adapter for connecting the hose joint 2 and the hose 3 and maintaining the state in which the wire bundle 6 is inserted into the wire insertion port 21. The hose adapter 10 prevents the wire bundle 6 from coming out of the wire insertion port 21.

With the above configuration, the contact piece 82 of the ground terminal 8 has a belt-like shape and is attached to the outer periphery of the wire bundle 6, so that the contact surface with the inner wall of the wire insertion port 21 can be widened. Since 82 is pressed by the electric wire protection member 4, a stable contact state can be maintained.
Further, since the connecting portion between the ground wire 7 and the ground terminal 8 is protected by the plurality of wire protection members 4 inside the wire bundle, there is no fear of disconnection due to vibration or the like.
Furthermore, it is possible to prevent the ground terminal 8 from moving rearward by the rubber ring 9 attached to the wire insertion port opening side of the wire bundle 6 inserted into the wire insertion port 21, and the ground terminal contact piece 82 and the wire insertion can be prevented. The contact state with the inner wall of the mouth 21 can be maintained.

  The present invention relates to a grounding structure for an electric civil engineering work machine such as a concrete vibrator, and has industrial applicability.

The longitudinal cross-sectional view which shows the outline | summary of the concrete vibrator provided with the earthing device of this invention Similarly, cross-sectional view of the grounding device Figure showing a wire bundle with a grounding terminal and rubber ring attached

DESCRIPTION OF SYMBOLS 1 Concrete vibrator main body 2 Hose joint 21 Electric wire insertion port 3 Hose 4 Electric wire protection member 5 Electric wire 6 Electric wire bundle 7 Ground wire 8 Ground terminal 81 Connection part 82 Contact piece 9 Rubber ring 10 Hose adapter

Claims (3)

A ground wire is arranged inside a bundle of wires formed by bundling a plurality of wires protected by a wire protection member made of an elastic insulating material,
A ground terminal contact piece is attached to the outer periphery of the wire bundle,
A connection piece is connected to one end of the contact piece, and the connection piece is connected to the ground wire,
The wire bundle to which the ground terminal is attached is inserted into a wire insertion port having an inner wall that is electrically connected to the casing of the motor, and the contact piece of the ground terminal is sandwiched between the outer periphery of the wire bundle and the inner wall of the wire insertion port. A grounding device for an electric civil engineering work machine. The grounding device according to claim 1, wherein a connection portion between the ground wire and the ground terminal is held by a plurality of electric wire protection members. The grounding device according to claim 1 or 2, wherein a rubber ring is attached to the wire insertion port opening side of the wire bundle fitted into the wire insertion port.

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