JPS6347040Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a connection structure between an electrode and a nipple used in an electric arc furnace for steelmaking.

[Conventional technology]

When the graphite electrodes used in arc furnaces for steelmaking are consumed beyond a certain amount during use, a replacement electrode is connected sequentially from the rear end, but as the arc furnaces become larger and With the implementation of operations using large amounts of electric power, the above-described electrode replenishment method is becoming more important, and it is required that connections be made more reliably in a shorter time.

To connect the supplementary electrode to the electrode in use, as shown in FIG. The other end of the nipple 4 is screwed into the socket at the rear end of the electrode 5 to be used.

By the way, thermal stress due to mechanical shock during connection and high heat in the arc furnace will be concentrated at the connection part of the electrode. We are dealing with this by making it slightly smaller. That is, the geometrical spacing resulting from the dimensional difference between the nipple and the socket facilitates the fitting of the screws together, alleviates the shock at the time of connection, and acts effectively against thermal expansion.

However, conversely, the dimensional difference between the nipple and the socket causes loosening and poor fitting in the connection between the nipple and the electrode socket. That is, at the stage of presetting the nipple on the supplementary electrode, for example, if the nipple and electrode socket are screwed together with their threaded surfaces glued together, as shown in FIG.
Due to play caused by the difference in diameter of the threaded portions, the fitting becomes uneven, and the mutual axes 1 and 1' are likely to be misaligned. On the other hand, as shown in Fig. 3, if the axes of the socket and nipple are aligned and screwed in, the nipple will enter too far and a misalignment will occur between its maximum diameter part 2' and the end face 2 of the supplementary electrode, making it difficult to use. In some cases, the necessary nipple protrusion length cannot be obtained when connecting to an electrode.

In addition, even if the nipple is preset in a normal state on the replenishment electrode, the screw fit is weak due to the above-mentioned dimensional difference, and the nipple connection may become loose due to the effects of vibrations applied to the electrode during shipping and transportation of the replenishment electrode. This could lead to poor fitting.

The above-mentioned poor fit between the replenishment electrode and the nipple preset will also have a negative effect on the connection with the electrode in use, leading to accidents where the connection loosens during use and the electrode falls off, and local stress may be concentrated at the electrode connection. This causes accidents such as sockets and nipples to break.

Conventional methods for improving looseness and poor fitting in the connection between the above-mentioned supplementary electrode and nipple are as follows:
As described in Japanese Utility Model Publication No. 54-11334 and shown in FIG. 4, a recess 13 is formed at the periphery of the entrance of the socket 12 in which the nipple 11 is preset in the electrode 10.
An elastic locking piece 14 is inserted into the recess 13 to stop the movement of the nipple 11 in the rotational direction, thereby preventing the connection from loosening. A method has been considered to correct the misalignment of the mutual axes.

[Problem that the invention attempts to solve]

However, in the above improvement plan, the locking piece 1
In order to form the recess 13 into which the locking piece 14 is inserted, it is necessary to remove the screw threads of both the nipple 11 and the socket 12 by drilling or the like. This has the disadvantage of lengthening the working time and increasing processing costs. In addition, the nipple 1 is secured by the locking piece 14.
Since the rotation of the nipple 1 is prevented, the nipple 11 can be replaced in case of a defective nipple or for its repair, or in order to reuse a broken electrode.
When attaching and detaching the nipple, the locking piece 14 becomes a major hindrance to the work, and sometimes the locking piece 14 is forcibly removed, causing major damage to the nipple 11 and making it unusable.

In order to solve the above-mentioned problems, this invention prevents loosening of the connection and poor fitting between the nipple and the electrode socket, eliminates the need for additional machining, etc. for the nipple and the socket, and The object of the present invention is to provide an electrode-to-nipple connection structure that allows the nipple to be attached and detached without damaging the socket.

[Means for solving problems]

In order to solve the above problems, in this invention, in a connection structure in which half of the nipple is engaged and connected to a socket formed at the end of the electrode with a tapered screw, the nipple can be pulled out between the socket and the nipple. An elastic body is provided to bias in the direction.

[Effect]

With the configuration described above, the tapered screws that are engaged between the nipple and the socket are brought into contact and pressed together on one side of their threaded surfaces due to the biasing force of the elastic body that pushes the nipple in the withdrawal direction. This will prevent the screw from loosening. In addition, the biasing force acts as an acting force in the radial direction from the inclination of the thread surface, which is the action surface, and due to the alignment action that uniformly moves toward the axial center over the circumference of the thread,
This prevents the axis of the nipple from shifting from the center axis of the socket. Due to the action of the biasing force of the elastic body, loosening and poor fitting at the connection between the nipple and the electrode socket are simultaneously prevented, and a normal and reliable connection state is maintained.

〔Example〕

Next, an embodiment of this invention will be described based on the accompanying drawings.

As shown in FIG. 1, a socket 2 is formed at the end of the electrode 1, and an elastic body 6 is provided approximately at the center of the socket bottom 2a. This elastic body 6
The compressor has an appropriate compression stroke and a biasing force corresponding to the compression stroke, and is made of, for example, hard rubber, various elastic synthetic resins, or a metal disc spring. When the tapered screw 3 is engaged with the socket 2 and the half end of the nipple 4 is connected, the elastic body 6 becomes compressed between the bottom surface 2a of the socket and the distal end surface 4b of the nipple. The biasing force for compression forces the nipple 4 in the direction of coming out of the socket 2.

With the above configuration, the biasing force of the compressed elastic body 6 acts on the socket 2 and nipple 4, and acts to constantly apply preload to the engaged thread surfaces, thereby preventing the screws from loosening. Furthermore, the above-mentioned acting force also acts in the radial direction due to the inclination of the threaded surface, so that it acts to align the axis of the nipple 4 with the axis of the socket 2, and prevents the mutual axes from shifting.

Next, when connecting the electrode 1 to the working electrode 5, the force by which the nipple 4 connects the electrode 1 to the working electrode 5 is:
Since it acts in the same direction as the urging force of the elastic body 6, the connection state of the nipple will not loosen even when the electrodes are connected. Also, as a connection method often used at work sites, after temporarily tightening both electrodes, the screws are turned back a small amount and then tightened firmly using the recoil. for,
When the urging force of the elastic body 6 is added to the above-mentioned tightening force, the threaded surfaces of the socket and nipple are pressed together so strongly that they undergo considerable elastic deformation, and the effective strength of the nipple connection is extremely large. become.

The action of the biasing force of the elastic body 6 is also effective against vibrations applied during shipping and transportation of the electrode 1. In other words, due to the backlash of the threaded portion caused by the difference in diameter, vibrations There have been cases where the contact between the threaded surfaces is shifted from each other and the connection becomes loose, but the biasing force presses the threaded surfaces and eliminates the looseness, so the normal connection is maintained without the screw loosening.

On the other hand, the nipple 4 can be attached and detached by rotating it, but unlike the conventional method, it is not necessary to remove the locking piece inserted between the nipple 4 and the socket 2. This makes it easier to remove the locking piece, and the nipple 4 will not be seriously damaged by forcibly removing the locking piece, so the work can be carried out with peace of mind.

Note that the same effect can be obtained not only when the elastic body 6 is used alone but also when a plurality of elastic bodies are provided.
In addition to fixing the nipple with a fixture or adhesive, it is also possible to simply insert the nipple between the bottom 2a and the tip 4b of the nipple.

〔effect〕

In this invention, with the above configuration, the biasing force of the elastic body acts on the tapered threaded part between the nipple and the electrode socket, effectively preventing loosening of the nipple connection and poor fitting, and constantly A reliable and normal connection between the electrode and the nipple can be obtained. In addition, with the above configuration, it is only necessary to provide an elastic body of an appropriate shape between the nipple and the socket, so additional machining such as drilling is not required, and there is no need to cut out dimensions and insert the elastic body. This greatly improves workability and reduces processing costs. Furthermore, when attaching and detaching the nipple, there is no need to remove the locking piece that stops the rotation of the nipple, so you can attach and detach with confidence without damaging the electrode socket or nipple. It is expected that it will be of great use.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view of the main part showing an embodiment of the electrode connection structure according to this invention, FIGS. 2 and 3 are schematic sectional views illustrating an inappropriate connection part of the conventional structure, and FIG. 4 1 is a cross-sectional view of a main part showing a connection structure in a conventional example (Japanese Utility Model Publication No. 11334/1983) in which improper connection has been improved. 1... Electrode, 2... Socket, 3... Tapered screw, 4... Nipple, 6... Elastic body.

Claims (1)

[Claims for Utility Model Registration] (1) In a connection structure in which half of a nipple is connected to a socket formed at the end of an electrode for an arc furnace by engaging with a tapered screw, the nipple is connected between the socket and the nipple. A connection structure between an electrode and a nipple, characterized by being provided with an elastic body that biases the nipple in the direction of withdrawal. (2) The electrode-nipple connection structure according to claim 1, wherein the elastic body is provided between the bottom of the socket and the end face of the nipple.