JP2005232705A - Joint member for steel pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint member for a steel pipe for simply connecting two steel pipes to each other on the same axis while accurately transmitting a rotating force thereto. <P>SOLUTION: The joint member for the steel pipe comprises two steel pipe receiving cylinders with bottom plates. The receiving cylinders have steel pipe sockets opened via the common bottom plate in the opposite directions. On the inner faces of the steel pipe receiving cylinders, inclined protrusions are formed each of which protrudes gradually toward the center of the cylinder as going to the bottom plate. The bottom of each receiving cylinder has a center axis at the center the same as the center axis of the receiving cylinder. A bottom cylinder is provided therein whose outer diameter is not larger than the inner diameter of the steel pipe to be connected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a steel pipe joint member.

It may be necessary to connect and extend steel pipes that transmit rotational force on the same axis.
In that case, a simple structure such as a screw connection, a welding connection, or a connection penetrating a pin is well known without mentioning literature.

The above-described conventional steel pipe joint member has the following problems.
<1> The joint structure in which the screw is formed is simple and reliable. However, there is a problem in that the connection between the steel pipes is disassembled when the processing of the screw is expensive and the rotation is applied in the opposite direction.
<2> The method of welding the ends of the two steel pipes requires a special welder for welding, takes skill and time, and is uneconomical.
<3> There is also a method in which a short cylinder having an inner diameter larger than the outer diameter of the steel pipe is used, a steel pipe is inserted into the inside of the short cylinder from both sides, and a pin is penetrated and connected from the transverse direction. In that method, in order to transmit a large rotational force, a pin hole having a large diameter must be opened, which may cause a shear failure.

In order to solve the above-described problems, the joint member of the steel pipe of the present invention is a joint member that connects two steel pipes on the same axis, and is composed of two steel pipe receptacles having a bottom plate, Both receiving cylinders open a steel pipe receiving port in the opposite direction through a common bottom plate, and the inner surface of this steel pipe receiving cylinder projects an inclined protrusion that gradually protrudes toward the center of the cylinder as it reaches the bottom plate. In the center of the bottom of each receiving tube, a bottom tube having a central axis identical to the central axis of the receiving tube and having an outer diameter equal to or smaller than the inner diameter of the steel pipe to be connected is provided. When a steel pipe is inserted under pressure from the opposite direction, the steel pipe can be deformed in the center direction by the inclined protrusion, and the limit of deformation can be limited by the outer diameter of the bottom tube at the center of the bottom. It is characterized by a steel pipe joint member.

Since the steel pipe joint member of the present invention is as described above, the following effects can be obtained.
<1> Even if the steel pipe is rotated in either the left or right direction, it is not disassembled like a screw.
<2> The work of connecting steel pipes is simple and economical because it does not require skill or a long time.
<3> Since the rotational force is transmitted by the deformed surface of the steel pipe, there is no concern about shear failure as in the case of opening a bolt hole.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

<1> Overall description.
The joint member of the present invention is a joint member for connecting two steel pipes P on the same axis, and is a cylindrical body as a whole.
However, in order to make the structure easy to understand, description will be made on the assumption that the two receiving cylinders 1 are connected by the bottom plate 12.

<2> Receptacle 1.
The receiving cylinder 1 is a cylindrical body that opens the steel pipe P receiving port 11 and includes a bottom plate 12.
The inner diameter of the receiving port 11 is configured to be larger than the outer diameter of the steel pipe P to be connected. Therefore, the steel pipe P can be easily inserted from the receiving port 11.

<3> Inclined protrusion 13.
On the inner surface of the steel pipe P receiving cylinder 1, an inclined protrusion 13 that protrudes gradually in the center direction of the cylinder from the vicinity of the receiving port 11 toward the bottom plate 12 is projected.
The inclined protrusions 13 are provided at two or more locations on the inner surface of the receiving tube 1 and at a plurality of locations (four locations in the illustrated embodiment).
A certain condition is required for the dimension of the cross section that crosses the central axis of the receiving cylinder 1 at the position where one inclined protrusion 13 is located, that is, the diameter of the virtual circle.
That is, the diameter of the virtual circle between the inclined protrusions 13 in the vicinity of the receiving port 11 is sufficiently larger than the outer diameter of the steel pipe P to be connected. Therefore, the steel pipe P can be easily inserted from the receiving port 11.
However, the diameter of the virtual circle between the inclined projections 13 in the vicinity of the bottom plate 12 is sufficiently smaller than the outer diameter of the steel pipe P to be connected. Therefore, when the steel pipe P is inserted with a strong force, in the vicinity of the bottom plate 12, a part of the steel pipe P is forced to deform inward of the receiving cylinder 1 by the inclined protrusion 13.

<4> Bottom tube 14.
A bottom tube 14 is provided at the center of the bottom of the receiving tube 1.
The bottom cylinder 14 has the same central axis as the central axis of the receiving cylinder 1.
Furthermore, the outer diameter of the bottom cylinder 14 is smaller than the inner diameter of the steel pipe P to be connected.
Therefore, when a part of the steel pipe P is forced to be deformed inward of the receiving tube 1 by the inclined protrusion 13, a certain restriction is imposed on the inward deformation.

<5> Integration of the receiving tube 1.
As described above, the joint of the present invention has been described by being divided into the two steel pipes P receiving cylinders 1. These two receiving cylinders 1 are connected by opening a steel pipe P receiving opening 11 in the opposite direction via a common bottom plate 12 to constitute an integral joint.

<6> Parallel plane.
The inclined protrusions 13 extending from the vicinity of the receiving port 11 to the bottom plate 12 can be provided at the same angle in the entire extension, or a part of the angle can be changed.
That is, the parallel surface 15 is formed on a part of the surface facing the bottom tube 14 in the vicinity of the bottom tube 14 of the inclined protrusion 13.
The parallel surface 15 is formed in parallel with the central axis of the receiving tube 1 in parallel with the outer peripheral surface of the bottom tube 14.

<7> Inner protrusion.
An inner protrusion 16 may be provided on the outer peripheral surface of the bottom tube 14 provided on the bottom plate 12 in a direction parallel to the central axis of the receiving tube 1.
The inner protrusion 16 is disposed so as to be positioned between one inclined protrusion 13 and the adjacent inclined protrusion 13.
As a result, the steel pipe P to be connected is deformed from the outside by the inclined protrusion 13 and from the inside by the inner protrusion 16.

<8> Insert the steel pipe P.
Next, a method of connecting two steel pipes P on the same axis using the joint member J of the present invention will be described.
First, the steel pipe P is inserted from the receiving ports 11 on both sides of the joint member J of the present invention.
Thereafter, both steel pipes P are pressurized toward the joint member J.
A known method can be used as the pressurizing method. For example, a pressurizing apparatus A using a hydraulic jack as shown in FIG. 7 can be used.
In this case, a grip ring B that grips the steel pipe P from the outer periphery using a wedge or the like is used, and the two grip rings B are connected by a jack.
If each steel pipe P is gripped by each gripping ring B and the jack is shortened, both steel pipes P are strongly inserted toward the joint member J of the present invention.
In addition, if the holding ring B is configured to be divided into two by a pin parallel to the jack, the holding ring B can be attached to the steel pipe P at a free position and pressurized toward the joint member J. .

<9> Deformation of the steel pipe P.
The inserted steel pipe P is deformed in the center direction by the inclined protrusion 13, but the limit of deformation is limited by the outer diameter of the bottom tube 14 at the bottom center. That is, the end of the steel pipe P is not excessively deformed inward by the pushing force from the outer periphery.
As a result, the inclined projection 13 bites in from the periphery of the end of the steel pipe P, and the inner side surface is plastically deformed in a state where deformation is prevented by the bottom tube 14.
When the inner protrusion 16 is formed on the peripheral surface of the bottom tube 14, the steel pipe P is further deformed into a more complicated shape with the inner protrusion 16 biting in from the inner side.

<10> Transmission of rotational force.
The ends of both steel pipes P are completely connected in a state of being plastically deformed via the joint member J of the present invention.
As a result, not only the axial force of the pipes P on both sides can be transmitted, but also the rotational force in either direction can be satisfactorily transmitted.

Sectional drawing of the Example of the coupling member of the steel pipe of this invention. FIG. Explanatory drawing of the state before connecting a steel pipe. Sectional drawing of a coupling member. Explanatory drawing of the state of the steel pipe after a deformation | transformation. Sectional drawing of the other Example of a coupling member. Explanatory drawing of the state which connects a steel pipe.

Explanation of symbols

1: receiving tube 11: receiving port 12: bottom plate 13: inclined projection 14: bottom tube J: joint member of the present invention P: steel pipe

Claims (3)

A joint member connecting two steel pipes on the same axis,
Consists of two steel pipe receptacles with a bottom plate,
Both receiving tubes open steel pipe receiving openings in opposite directions through a common bottom plate,
On the inner surface of this steel tube receiving tube, as it reaches the bottom plate direction, an inclined protrusion that protrudes gradually toward the center of the tube is projected,
In the center of the bottom of each receiving tube, a bottom tube is provided that has the same central axis as the central axis of the receiving tube and has an outer diameter equal to or less than the inner diameter of the steel pipe to be connected,
When a steel pipe is inserted into each receiving tube from the opposite direction,
The steel pipe can be deformed in the center direction by the inclined protrusions,
And configured to be able to limit the limit of deformation by the outer diameter of the bottom cylinder in the center of the bottom,
Steel pipe joint member.
The slanted protrusion from the vicinity of the receiving port to the bottom plate is
In a part of the surface facing the bottom tube,
A parallel surface formed in parallel with the outer peripheral surface of the bottom tube,
Formed in the direction parallel to the central axis of the receiving tube,
The steel pipe joint member according to claim 1.
On the outer peripheral surface of the bottom cylinder provided on the bottom plate,
The projections for imparting deformation are configured to project in a direction parallel to the central axis of the receiving cylinder.
The steel pipe joint member according to claim 1.

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