JPH0417923A - Manufacture of elbow fitting for piping - Google Patents

Abstract

PURPOSE:To improve the productivity by using the straight pipe which has the diameter and total length being suitable for the elbow fitting of piping, forming the fitting parts at the both ends preliminarily, clamping the fitting part of the front end with the bending die and clamping die, setting the straight pipe at the pipe bender and bending it with two processes of the regular and opposite. CONSTITUTION:The bending die and the clamping die are rotated by the prescribed angle on the initial process, rotated to the opposite direction by some angle on the next process and executed with bending, so the bending amount of the pipe to be bent can be set for some quantity larger due to the rotated amount of the opposite direction. On the result, after rotating to the opposite direction, the inner circumferential surface of the pipe part to be bent is separated from the circumferential side surface of the clamping die 30 and some clearance is generated from the circumferential side surface on the horizontally sectional plane, and so the bent part of pipe 12 is formed. Accordingly, the elbow fitting 10 for piping can be taken out easily with swinging from the bending die, and the fitting parts 11 of expanded shape are formed preliminarily at both ends of the straight pipe, and the straight pipe 20 formed with this fitting parts can be bent by the prescribed angle with utilizing the pipe bender.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a piping elbow joint used for connecting fluid piping.

[Technology from the past] Elbow joints, such as elbows and vents, are often used in the assembly of various fluid piping.These elbow joints for piping have joints formed at both ends of the bent pipe, and Regardless of the type of fitting, such as a push-in type or a screw type, the outside shape of the joint is often a bulge shape. Conventionally, elbow joints for piping that form such a bulge-shaped joint part are used for pipes. A straight pipe is bent at a specified angle using a bender to produce a bent pipe in the first process, and in the next process both ends of the marked pipe are processed to form a joint with a specified joint method. It is generally manufactured as follows.

[Problems to be Solved by the Invention] However, in this method of manufacturing elbow joints for piping, forming the joint portions at both ends of the bent pipe requires separate processing, and the work is complicated and unsuitable for mass production. This was not a preferable method from the viewpoint of workability and productivity. Therefore, in order to improve productivity, it is more reasonable to form joints at both ends of a straight pipe in advance and bend the straight pipe at a predetermined angle using a pipe bender. However, in this case, after the joint is gripped by the bending mold and clamp mold of the pipe bender and the bending mold is rotated to perform the bending process, the bulging joint part is engaged with the circumferential side of the bending mold. There is a drawback that it becomes difficult or impossible to remove the elbow joint for piping from the bending mold. This was a major hindrance, and it was not possible to adopt such a manufacturing method.

This invention aims to solve these problems, and provides a new piping system in which joints are formed in advance at both ends of a straight pipe, and the straight pipe is bent at a predetermined angle using a pipe bender. The purpose of the present invention is to provide a method of manufacturing an elbow joint for use, improve workability and productivity, and, as a result, reduce manufacturing costs.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides an elbow joint for piping in which a joint portion having a bulged external shape is formed at both ends of a bent pipe portion. This provides a method for manufacturing in the following steps.

First, a straight pipe with a diameter and full length suitable for an elbow joint for piping is used, and a joint portion is previously formed at both ends of the straight pipe by an appropriate processing method such as plastic working or cutting.

Next, the straight pipe with the joint formed thereon is gripped by the joint at the front end with a bending die and a clamp die, set in a pipe bender, and bent by rotating the bending die and the clamp die in conjunction with the bending die. to form a bent pipe section. This bending process is set to be performed in two forward and reverse steps, in which the bending mold is rotated by a predetermined angle in the bending direction in the first step, and then rotated in the opposite direction of the bending angle in the next step.

The manufacturing method of the present invention includes a plug-in joint that connects the pipe by inserting the pipe to be connected into both ends of the bent pipe, a screw-in joint that connects the pipe by screwing the pipe to be connected, and a hose. Applicable to elbow joints for piping, etc. that form joints for connecting hoses with protruding parts to prevent separation.

If the elbow joint for piping is a 90° elbow joint that is often used, the bending process should be performed at 90° in the bending direction in the first step.
It is reasonable to set it so that it is rotated by α° and then rotated in the opposite direction by α° in the next stroke.

[Function] According to the method for manufacturing an elbow joint for piping of the present invention, the bending mold and the clamping mold are rotated by a predetermined angle in the bending direction in the first step, and rotated in the opposite direction of the weak crown angle in the next step. By performing the bending process, the amount of bending of the bent pipe portion is set to be slightly larger depending on the amount of rotation in the opposite direction. As a result, after the reverse stroke, the inner circumferential side of the bent tube section is separated from the circumferential side of the bending mold, creating a gap between the circumferential side and the crown in a planar cross section, thereby forming a bent tube section. Therefore, the elbow joint for piping can be easily removed from the bending mold by swinging, and the straight pipe with the joints formed in the bulge shape can be formed in advance at both ends of the straight pipe.
It is possible to adopt a method of bending the pipe to a predetermined angle using a pipe bender.

The present invention forms a joint having a bulged external shape, regardless of the type of joint, such as a plug-in joint, a screw-in joint, or a joint for connecting a hose. Used in many elbow joints for piping.

In addition, the bending angle of the bent pipe part can be adapted to various types, especially in the case of a 90° elbow, the first stroke is to rotate it 90+α° in the bending direction, and the next stroke is to rotate it in the opposite direction by α°. By setting the bent pipe part to 90"
It is rational and bent.

The configuration and effects of the present invention will be specifically explained below with reference to the embodiments shown in the drawings.

[Example] The elbow joint for piping (10) shown in FIG.
2) with insert-type joints (11) formed at both ends of the 9
At the 0° elbow, connect the pipe to be connected and its end to the joint (11)
It is connected by inserting it inside.

The manufacturing process according to the present invention will be explained below.

First, use a straight pipe (20) with a diameter and full length that matches the piping elbow joint (10) to be manufactured (see Figure 2), and attach the joint parts (11) to both ends of the straight pipe (20>). It is preformed into a predetermined bulging shape (see FIG. 3).

Next, the straight pipe (20) with the joint part (11) formed thereon is set in a pipe bender for bending.

The pipe bender bends the front end of the pipe to be processed (30)
and a clamp mold (35), and press the rear part with a clamp mold (40).
) and the receiver are held by a mold (45), and with the center of the arc part of the bending mold (30) as the center of rotation, the bending mold (30) and the clamp mold (35) are rotated in conjunction with this, and a predetermined shape is formed. This is a general configuration for bending at an angle of . The circumferential side surface (31) of the bending mold (30) is formed in a semicircular shape that matches the outer shape of the straight pipe (20), and a four-part shaped gripping surface ( 32) is formed, and a similar concave-shaped gripping surface (36) is formed on the inner surface of the clamp mold (35), facing the gripping surface (32). Similarly, the inner surface (41) of the holding mold (40) is formed in a semicircular shape that matches the outer shape of the straight pipe (20), and the joint part (1) is formed at the rear.
A concave-shaped holding surface (42) that matches the external shape of item 1) is formed, and the receiver is placed in the mold (4) opposite to the holding surface (42).
5) is also formed with a similar concave-shaped holding surface (46).

The straight pipe (20) has its bent inner circumference side in contact with the gripping surface (32), the clamp mold (35) is closed and its bent outer circumference side in contact with the gripping surface (36), and the front end joint portion (11). ) into a bending mold (3
0) and a clamp mold (35) and set on a pipe bender. On the other hand, bend the outer peripheral side back to the inner surface (41
), the rear end of the bent inner circumferential side abuts the holding surface (46), the straight pipe (20) is held by the holding die (40), and the receiver is placed by the die (45).
It is held with. A core member (50) is inserted from the front end opening of the straight pipe (20) and comes into contact with the inner peripheral surface of the joint part (11) at the front end to prevent deformation during processing, and also to prevent deformation. A collar member (51) that contacts the inner peripheral surface of the joint portion (11) at the rear end is provided in advance, and a ball core metal (52) is inserted through the rear end opening of the straight pipe (20) to prevent wrinkles. A ball (53) is provided at a position where the straight pipe (20) is to be bent (see FIG. 5).

Next, bending is performed by rotating the bending die (30) and the clamp die (35). Interlocked with the rotation of the bending mold (30),
The holding mold (40) and the receiver are configured so that the mold (45) moves in the feeding direction, and the straight pipe (20) is bent along the circumferential surface (31) of the bending mold (30), and the bent pipe part ( 12) is formed. In this bending process, the bending die (30) and the clamp die (35) are rotated by a predetermined angle in the bending direction in the first step, and then rotated in the opposite direction of the weak crown in the next step.
In this example, the first stroke is set to rotate 90 + α degrees in the bending direction, and the next stroke is set to rotate α degrees in the opposite direction, and α is set to 5 to 6 degrees. (See Figure 4). Therefore, the bent pipe part (
12) is set slightly large, and in the next reverse rotation stroke, the inner circumferential side of the bent pipe part (12) separates from the circumferential side surface (31) of the bending mold (30), and the circumferential side surface ( 31) and a weak crown gap (13), bending is performed at a bending angle of 90° to form a piping elbow joint (10) (see Fig. 6).

After the bending process, the clamp die (35), presser die (40), and receiver move the die (45) outward to open it.
The core member (50) and the hole core (52) are pulled out, and the elbow joint for piping (10) is removed from the bending die (30). At this time, the elbow joint for piping (1
0) is allowed to swing slightly, and it is easy to bend the mold (3
0> (see Figure 7).

FIGS. 8 to 10 illustrate other elbow joints to which the method for manufacturing elbow joints for piping of the present invention can be applied.

The elbow joint for piping (10a) in Fig. 8 has a bent pipe section (10a).
2) is a 90° elbow with threaded joint parts (11a) formed at both ends, and a female thread part (15) is formed on the inner peripheral surface of the joint part (11a), and the pipe to be connected is connected to the end thereof. The connection is made by screwing in the male thread.

Then, the external shape of the joint part (11a) is formed into a bulging shape, or the joint part (11a) is
) can be manufactured by bending a pre-formed straight pipe.

FIGS. 9 and 10 show the formation of a joint part (11b>, (11c)) for connecting a hose, which is provided with a bulge part to prevent the hose from coming off.

The elbow joint (10b) for piping shown in Fig. 9 is provided with annular bulges (16) for preventing hose separation at positions close to both ends to form a joint part (11b), and the elbow joint (10b) for piping shown in Fig. The elbow joint (10c) has a bulge from both ends to prevent the hose from coming off (
17) to form a joint portion (Ilc). The joint parts <1ib) and (11c) can be formed in advance at both ends of a straight pipe according to the process of the present invention, and then bending can be performed.

[effect] The characteristic effects of this invention are as follows.

When performing bending by rotating the bending die (30) and clamp die (35), in the first step they are rotated by a predetermined angle in the bending direction, and in the next step, the angle of the weak crown is rotated in the opposite direction. By performing the bending process in two steps, after the bending process, the piping elbow joint (10) with the bulge-shaped joint part (11) formed can be easily removed from the bending die (30), and the pipe joint (10) can be removed directly from the bending die (30). This makes it possible to employ a method of manufacturing an elbow joint for piping by forming the joint parts (11) at both ends of the pipe (20) in advance and then bending the straight pipe (20).

Therefore, the joints (11) are formed at both ends of the straight pipe (20), unlike conventional bent pipes, so continuous work can be performed using appropriate processing methods such as plastic working and cutting. It is said that the processability and workability are improved, and the bending process using a pipe bender is improved.

Since the rotation of the bending die (30) is simply operated and controlled in two forward and reverse strokes, it has excellent productivity, is suitable for mass production, and can greatly reduce manufacturing costs.

Also, by rotating the angle of the weak crown in the opposite direction, the springback of the bent pipe section (12) can be absorbed.

This has practical effects such as being able to accurately control the bending angle.

In addition, the present invention is applicable to many types of joints in which the external shape of the joint is formed into a bulged shape, regardless of the type of joint, such as a plug-in type joint, a screw-in type joint, or a joint for connecting a hose. Can be applied to elbow joints for piping, bent pipe parts (
The bending angle of 12) can also be adopted for various elbow joints for piping, and has a variety of uses. In particular, in the case of a 90° elbow, by setting it so that it is rotated by 90° in the bending direction in the first stroke, and then rotated in the opposite direction by α° in the next stroke to return the rotation angle to 90°. 9
A 0° elbow can be formed accurately and uniformly.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a partially cutaway plan view of a piping elbow joint forming a plug-in joint;
Figures 2 to 7 show the manufacturing process, Figure 2 is a partially cutaway plan view of the straight pipe used, and Figure 3 is a partially cutaway plan view of the straight pipe with joints formed at both ends. , Fig. 4 is a plan view of the straight pipe set in the pipe pengu, Fig. 5 is a sectional view of Fig. 4, Fig. 6 is a sectional plan view of the pipe bender after bending, and Fig. 7 is a pipe bend. 8 to 10, which are cross-sectional plan views showing the state in which the joint is removed from the pipe bender, are other embodiments to which the present invention is applied, and FIG. A plan view with the section broken away,
Figure 9 is a partially cutaway plan view of a piping elbow joint that forms a joint for connecting a hose, and Figure 10 is a partially cutaway plan view of a piping elbow joint that forms a joint for connecting another hose. FIG.

Claims (1)

[Scope of Claims] 1. A method for manufacturing an elbow joint for piping in which a joint part (11) having a bulged external shape is formed at both ends of a bent pipe part (12), comprising: Straight pipe with pipe diameter and full length (20
) to form joints (11) at both ends of the straight pipe (20), and then grip the joints (11) at the front end with a bending die (30) and a clamp die (35). The straight pipe (20) is set in a pipe bender, and the bending die (30) and the clamp die (35) are rotated in conjunction with this to form the bent pipe part (12). Forward/reverse 2: Rotate a predetermined angle in the direction, and then rotate the angle of the weak crown in the opposite direction in the next step.
A method for manufacturing an elbow joint for piping, characterized in that it is set to be performed in a stroke. 2. Plug-in joint for connecting by inserting the pipe to be connected (
11) The method for manufacturing an elbow joint for piping according to claim 1. 3. A screw-in joint that connects the pipe to be connected by screwing it in (
11. The method for manufacturing an elbow joint for piping according to claim 1, wherein the elbow joint for piping is formed as follows. 4. The method for manufacturing an elbow joint for piping according to claim 1, wherein the joint parts (11b) and (11c) for connecting the hose are provided with a bulge part for preventing the hose from coming off. 5. Claims 1 and 2, wherein the elbow joint for piping is a 90° elbow.
, 3 or 4, the method for manufacturing an elbow joint for piping. 6. The method for manufacturing an elbow joint for piping according to claim 5, wherein the bending process is performed by rotating the bending direction by 90+α degrees in the first step and rotating it by α degrees in the opposite direction in the next step.