JPH0680981U - Structure of casing pipe joint - Google Patents

Abstract

(57) [Abstract] [Purpose] In the structure of the joint part of the casing pipe for burying the underground line, the casing pipe and the propulsion pipe, the outer periphery of one of the pipe ends. The taper male thread and the taper female thread provided on the inner circumference of the other pipe end have a trapezoidal cross-section, so that the thread has high strength equivalent to a square thread and is high. It has accuracy, facilitates hand tightening, has good water-tightness and air-tightness, and ensures the workability of pipes and the safety of connection parts. [Structure] A taper male screw is provided on one pipe end of the pipe, and a taper female screw is provided on the other pipe end, and the male screw and the female screw have a trapezoidal cross section and are joined together. At this time, the pipe and the joint portion of the pipe have the same inner diameter and outer diameter.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure of a casing pipe jointing portion for connecting a casing pipe for burying an underground wire, a thrust pipe and a propulsion pipe.

[0002]

[Prior art]

 Conventionally, pipe screws have been required to have airtightness and watertightness, so triangular screws have been provided, and female threads have parallel male threads or taper male threads and parallel female threads or taper female threads. It is well known that various types of stitches are provided. In addition, as for the thrust tube and the propulsion tube, a square screw with a strong thread is generally provided as a parallel screw parallel to the pipe axis in order to cope with a large force applied to the joint in its application.

[0003]

[Problems to be solved by the device]

 At the joint part of conventional underground pipe casing pipes, if the pipe slips out or the safety of the joint such as watertightness and corrosion resistance is impaired, the life of the entire pipe is shortened. The safety of must be ensured. Moreover, in addition to this, since a large number of pipes are connected, the fastening work is easy to handle and efficient workability is required in the piping work. In addition, even in the case of a straightening pipe and a propulsion pipe, in order to maintain the life of the entire pipe for a long time, the safety of the joint such as watertightness and corrosion resistance should not be impaired, and the piping work Needless to say, easy handling and efficient workability are required for fastening work in order to reduce costs.

However, in the conventional pipe thread of this type described in the prior art, even if the triangular screw secures the safety of the connection portion against watertightness and airtightness, the triangular screw has a weak thread strength. Therefore, there was a problem with the durability of the joint when they were joined. On the other hand, even though the parallel threads that are used as the square threads provided on the thrust tube and the propulsion tube have sufficient strength to withstand the large force that acts on the joint, the square threads have a thread shape. Since it has a square cross section and is provided as a parallel screw parallel to the pipe axis, it is difficult to tighten by hand and requires a lot of time for piping work that requires connection of many pipes. , The clearance between the male and female threads is increased to loosen the snap-eye diameter, and therefore the accuracy is low and the catching rate is also low.Therefore, there is a gap between the screws, resulting in loosening of the snap-eye. However, there was a problem that the watertightness and airtightness were extremely poor as the size increased.

In the propulsion method, usually, a lead pipe (pilot pipe) is reached in the first step, and then a sediment capturing head (pressing head) matching the outer diameter of the buried pipe is connected in the second step. It is a construction method in which a buried pipe is connected, and the buried pipe is pressed and propelled without rotating.If the propulsion pipe does not receive a direct propulsion force, if there is a protrusion etc. on the outer surface of the pipe, it will not be mixed with earth and sand during propulsion. Since the peripheral resistance due to contact increases, there is a problem that the peripheral surface of the buried pipe, especially the connecting part of the pipe, must be formed in a shape without protrusions that cause peripheral resistance during propulsion. It was Similarly, even in the case of the boring method, a metal bit or metal crown that matches the diameter of the projection of the buried pipe is required, and it is difficult to equip it with the metal surface. Had a problem that it had to be formed into a shape without protrusions.

The present invention has been made in view of the above-mentioned points described in the prior art, and an object of the present invention is to provide a taper screw having a trapezoidal thread on the outer circumference of one pipe end of the pipe. By installing a screw and a taper female thread that becomes a trapezoidal thread on the other pipe end, the thread has the same strength as a square thread, facilitating manual tightening and good water-tightness. It is intended to provide a structure of a joint portion of a casing pipe that is airtight and can surely secure the workability of a pipe and the safety of a connecting portion.

[0007]

[Means for solving problems]

 In order to achieve the above object, in the structure of the joint portion of the casing sleeve of the present invention, a taper male screw is provided at one pipe end of the pipe and a taper female screw is provided at the other pipe end. The external thread and the internal thread are such that the thread shape is trapezoidal in cross section, and the joint portion when coupled has the same inner diameter and outer diameter as the pipe.

The taper is 1/50 or 1/25 depending on the type of pipe diameter, and the male thread and female thread are provided with a thread shape at right angles to the pipe axis and a flank angle of 14 It is preferable that the trapezoid has a trapezoid of 0.5 degree and four peaks are provided per inch.

[0009]

[Action]

 When connecting pipes to each other, it is extremely easy to tighten them by hand by using a taper male screw and a taper female screw, and a trapezoidal cross-section screw thread can reduce the gap between the thread widths, so loose fitting is possible. It has a small size and has a significantly improved catching rate. Therefore, it has sufficient strength to receive a large force applied to the joint and is excellent in watertightness and airtightness. Ensure efficient workability in piping work and high safety of joints without increasing peripheral resistance due to contact with earth and sand, and reduce piping costs that require the connection of multiple pipes. be able to.

[0010]

【Example】

 An embodiment will be described with reference to the drawings. As shown in FIGS. 1 and 2, a pipe 1 is provided with a taper male screw 2 on the outer periphery of one pipe end and a taper on the inner periphery of the other pipe end. -A taper screw 3 is provided, and the taper male screw 2 and the taper female screw 3 are provided with a trapezoidal screw 4 having a trapezoidal cross section as shown in FIG. The taper male screw 2 and the taper female screw 3 have an inner diameter and an outer diameter of the joint portion when the pipe 1 and another pipe 1'are combined, as shown in FIG. 5'and the outer diameter 6, 6'have the same inner and outer diameters.

[0011] The taper is better to be strong for facilitating the interference, but if the wall thickness of the pipe end becomes too thin, it is likely to be deformed in handling. For example, JIS G3452 pipe carbon steel pipe SGP Then, it is preferable that the taper is 1/50 and the height of the screw thread is 1.00 mm. In the JIS G3454 carbon steel pipe for pressure pipe STPG370, the taper is 1/25 and the screw thread is It is preferable to have the height of 1.5 mm or 2.0 mm.

The male thread 2 and the female thread 3 are preferably provided with a thread shape at right angles to the tube axis and have a trapezoidal cross section with a thread angle of 29 degrees or 30 degrees.

It is preferable that the external threads and the internal threads have four threads per inch. For example, when the trapezoidal screw pitch is 6.35 mm and the number of effective threads is 5, the strength is equivalent to the compressive strength of the pipe, and the pulling force is sufficient. With less rotation, the safety of piping work and efficient workability can be secured.

[0014]

[Effect of device]

 The present invention, which has the above-described structure, provides a pipe joint section having a trapezoidal taper male screw and a taper screw, and further, the fastening work is easy and the efficiency in the piping work is improved. It has good workability, has a large removal prevention force, is excellent in watertightness, and has high safety of the connection part. No surface resistance is generated, and therefore, there are advantages that the piping cost is low, and the life of the entire piping is semipermanently maintained.

[Brief description of drawings]

FIG. 1 is a perspective view of a pipe having a taper male screw and a taper female screw according to the present invention.

FIG. 2 is a cross-sectional view of essential parts of a taper male screw and a taper female screw of the present invention.

FIG. 3 is a cross-sectional view of an essential part of a joint portion of the present invention in which the joint portion is connected and shown.

FIG. 4 is an enlarged cross-sectional view of a main part of a screw provided on the pipe of the present invention.

[Explanation of symbols]

 1 pipe 2 taper male screw 3 taper female screw 4 trapezoidal screw 5,5 'pipe inner diameter 6,6' pipe outer diameter

Claims (1)

[Scope of utility model registration request] 1. A taper external thread is provided on one pipe end of the pipe,
A taper female screw is provided at the other pipe end, and the male screw and the female screw have a trapezoidal cross section, and the joint portion when joined has the same inner diameter and outer diameter as the pipe. A structure of a joint portion of a casing pipe, which is characterized in that