JPH07314496A - Joint molding method and molding device - Google Patents

Abstract

PURPOSE:To provide a method for molding a joint in which the inner core of a plurality of types of tube joints can be efficiently molded by one operator. CONSTITUTION:Different types of metal joint bodies 3 are set on one turntable 26. The turntable 26 is intermittently rotated. Melted plastic is injected in an injection molding station under the injection condition corresponding to the type of the body 3 to mold an inner core.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for molding a corrosion resistant joint having an inner core portion.

[0002]

2. Description of the Related Art Conventionally, a metal joint body is set on a turntable, and the inner core portion is injection-molded in the joint body at an injection molding station while intermittently rotating the turntable. The device is widely used.

By the way, conventionally, one type of metal joint body was sequentially set on one turntable and injection-molded, which is suitable for mass production and can be efficiently manufactured.

[0004]

However, there are many types of corrosion-resistant pipe joints of this type: elbows, cheeses,
Or because there are large and small dimensions (caliber), etc.,
In many cases, high-mix low-volume production is required.

Therefore, a large number of manufacturing apparatuses are required, and there is a problem that the operating rate is extremely deteriorated, and many workers are required.

[0006]

According to the joint molding method of the present invention, metal joint bodies of different kinds are set on one turntable, and the turntable is intermittently rotated to sequentially form a plurality of stations. It is a method of molding the inner core portion by injecting molten plastic under the injection condition corresponding to the type of the joint main body at one of the plurality of stations at an injection molding station.

Further, a reference part for detection is attached at one position around the turntable, the reference part is detected by a detector on the fixed side, and further, a metal joint body of a different type is used as the reference. Set in a predetermined order in the circumferential direction from the section to be intermittently sent to the injection molding station, and the detection signal from the detector identifies the joint body corresponding to the injection molding station and injects accordingly. The molten plastic is injected under the conditions.

Further, the joint molding apparatus of the present invention comprises a turntable which intermittently repeats rotation stop, and a plurality of different types of metal joint bodies which are provided on the turntable so that they can be set. The joint body holder, the stations arranged around the turntable, and the injection molding station, one of the stations, are installed to inject molten plastic into the joint body to mold the inner core portion. And the control means for controlling the injection machine to the injection conditions corresponding to the type of the joint body that has come to the injection molding station.

[0009]

[Function] The different types of metal joint bodies can be set on one turntable, and the injection molding station is injected under injection conditions such as pressure and injection amount according to the type, so that the inner core is Accurately molded.

A single worker can successively manufacture a plurality of types of corrosion-resistant pipe joints, which enables efficient production of a wide variety of products in small quantities.

Further, if a method of detecting one reference portion for detection on the turntable by a detector is used, the detection and control are simplified.

[0012]

The present invention will be described in detail below with reference to the illustrated embodiments.

1 (a), (b), (c), and (d) show different types of corrosion-resistant pipe joints 1, each of which is composed of a metal joint body 3 and an inner core portion 8.

Each joint main body 3 has female screw portions 2 and 2 at the ends thereof, and the core portion 8 is made of plastic and is for preventing corrosion of the inner surface of the joint main body 3. The core portion 8 protects the inner peripheral surface of the female screw portion 2, the substantially cylindrical sealed inner cylindrical body 6 having a predetermined gap portion 5, and the inner surface 7 of the joint body 3 excluding the female screw portion 2. And part 4.

More specifically, a cylindrical gap portion 5 is formed from both ends of the intermediate inner surface protection portion 4,
A hermetically sealed inner cylinder 6 is provided in a protruding manner, and a thread-shaped spiral ridge 9 having the same pitch and the same direction as the female screw portion 2 is formed on the outer peripheral surface of the inner cylinder 6.

FIG. 7 is a schematic view showing an embodiment of the joint molding method and joint molding apparatus according to the present invention.
The pipe joints 1 of different types (for example, four types) such as (a), (b), (c), and (d) of FIG. 1 described above can be manufactured by using one turntable 26.

The turntable 26 rotates as indicated by an arrow A ... While intermittently repeating rotation stop (via a motor (not shown) and a speed reduction mechanism). Reference numeral 27 denotes a joint body holder for setting the joint body 3 on the upper surface of the turntable 26 by gripping or grasping the joint body 3. In FIG. 7, four joint body holders 27 ... Are evenly arranged at the central angle of. Note that 28 indicates the center of rotation of the turntable 26.

In the example of FIG. 7, the turntable 26
There are four stations arranged on the fixed side (floor side) along the periphery of, for example, the first station is a set and take-out station, the second station is an injection molding station, the third station is a cooling station, The fourth station will be the screw return and spool removal station.

29 is an injection machine, which is installed at an injection molding station corresponding to the second station,
Molten plastic is injected into the inside of the joint body 3 (as shown in FIG. 1) to mold the inner core portion 8. Reference numeral 30 denotes a nozzle that reciprocates between a solid line and an imaginary line in FIG. 7, and injects molten plastic into the joint main body (not shown) in the holder 27 stopped at the second station.

The four joint body holders 27 in FIG. 7 hold, for example, four types of joint bodies 3 (see FIG. 1). Since the injection conditions such as injection pressure and injection amount differ for each type,
The injection unit 29 is controlled by the control means 31 including an electronic circuit such as a computer.

Reference numeral 32 denotes a detector, for example, a reference portion 33 for detection is attached at one position around the turntable 26, which is indicated by an asterisk in FIG. The reference unit 33 is detected by a detector 32 such as a sensor, a magnetic sensor or a limit switch. The four types of joint bodies 3 are set in a predetermined order from the one closest to the reference portion 33, and the injection conditions are input in advance in the set order by the input means 34 such as a keyboard and an operation panel. I'll do it. By doing so, it is possible to identify the joint body 3 that is sequentially sent to the second station (injection molding station) intermittently and inject the molten plastic under the injection conditions corresponding to that.

In addition to this, of course, the holder 27 itself is provided with an identification target part such as a bar code, or the identification targets are provided at four locations (with a central angle of 90 degrees) around the turntable 26. A detector is attached and detected by the detector 32,
You may input into the control means 31.

In short, according to the method of molding the inner core of the corrosion-resistant joint according to the present invention, different types of metal joint bodies 3 are set on one turntable 26, and the turntable 26 is intermittently mounted. It is rotated and sequentially stopped at a plurality of stations, and in one of the plurality of stations, an injection molding station, the molten plastic is injected under injection conditions corresponding to the type of the joint body 3 to form the inner core portion 8. Mold.

An example of a die jig device used for injection molding is shown in FIGS. 2 and 3 correspond to the first station, FIG. 4 corresponds to the second station, FIG. 5 corresponds to the third station, and FIG. 6 corresponds to the fourth station.

2 to 6, a die jig device 35 for molding a core has a female screw portion 2 formed at an end portion of the joint body 3.
Screw core (cylindrical core) 10, 10 having an engaging portion that is screwed to 2 and engages in a liquid-tight manner, and the screw core (cylindrical core) 10,
The first and second slide core pins 11a and 11b which are inserted into the main body 3 are inserted into the main body 3, and the tip inclined surfaces 12a and 12b of the slide core pins 11a and 11b are butted against each other. The pins 11a and 11b are made to have their axes Oa and Ob perpendicular to each other, and in this state, molten plastic is injected into the main body 3 to form the internal core portion 8 inside the main body 3.

That is, the screw core 10 is made of a cylindrical body, and a male screw portion 13 which can be screwed into the female screw portion 2 of the joint body 3 is formed at the tip portion thereof. Further, the through hole 14 of the screw core 10
A screw portion 16 is formed at the tip of the.

Further, the slide core pins 11a and 11b have small-diameter portions 15a and 15b at their tips, respectively, and their tips are the above-mentioned tip inclined surfaces 12a and 12b. That is, this pin 11
Reference characters a and 11b function as cores, so that the inner surface of the sealed inner cylinder body 6 and the inner surface of the inner surface protection portion 4 are formed into a continuous curved surface, and form the inner surface of the flow path of the joint 1. become.
The inclination angles of the tip inclined surfaces 12a and 12b are set to 45 °, and when the pins 11a and 11b are inserted into the joint body 3 and abutted against each other as shown in FIG.
b is in close contact with each other.

Therefore, the first slide core pin 11a is provided with a spool hole 17 for injecting the molten plastic into the main body 3, and at the tip of the spool hole 17, a discharge nozzle hole that opens inside the main body 3 is provided. 18 are lined up.

That is, the diameter of the spool hole 17 is gradually reduced toward the tip thereof, and the spool shaft center Os thereof is inclined by a predetermined angle θ _{1 with} respect to the pin shaft center Oa.

Specifically, the predetermined angle θ ₁ is set to be equal to or less than the inclination angle θ ₃ formed by the spool shaft center Os and the spool hole inner peripheral surface 19, and the tip of the spool hole 17 is set to the first slide core pin 11.
It is arranged near the tip edge 20 of the tip inclined surface 12a of a.

Therefore, the inner peripheral surface 19 of the spool hole 17 is gradually expanded from the tip end to the base end or is parallel to the pin axis Oa.

The discharge nozzle hole 18 has a spool shaft center O.
is inclined at a predetermined inclination angle θ _{2 with} respect to s,
The length dimension h is made as small as possible. In this case, it is preferable that the predetermined inclination angle θ ₂ is about 20 ° to 30 °.

Then, the base end opening 21 of the spool hole 17 is formed.
Then, the nozzle 30 of the injection machine 29 (shown in FIG. 7) is pressed so as to approach and separate, and abuts. The second slide core pin
In 11b, the spool hole 17 and the like are omitted, and it reciprocates up and down by a pressing cylinder or the like.

Next, a method of molding the core portion 8 of the joint 1 using the apparatus constructed as described above will be described.

First, in the first station, as shown in FIG. 2, the female screw portions 2 and 2 of the main body 3 are screwed with the male screw portions 13 and 13 of the screw cores 10 and 10, respectively. , 10 are attached, and the slide core pins 11a, 11b are further inserted to bring the tip inclined surfaces 12a, 12b into contact with each other as shown in FIG. This completes the set.

After that, when the turntable 26 is rotated to be sent to the second station and stopped, the injector 29 moves forward as shown by the arrow B and the nozzle 30 as shown in FIGS. 7 and 4.
Of the pin 11a is pressed against the base end opening 21 of the spool hole 17 of the pin 11a, and at the same time, the base end of the other pin 11b is pressed by another pressing cylinder. In this way, the pins 11a and 11b are brought into a butted state, and the cavity 22 is formed in the joint body 3. Next, molten plastic is injected from the injection machine 29 into the cavity 22 through the spool hole 17 and the discharge nozzle hole 18 (indicated by dots in FIG. 4). Immediately after the injection is completed, the nozzle 30 retracts.

After that, the turntable 26 is rotated to be sent to the third station, where the injected (injected) molten plastic is cooled and becomes solidified plastic as shown in FIG.

Next, the turntable 26 is rotated to move to the fourth position.
Sent to the station. As shown in FIG. 6, the first and second slide core pins 11a and 11b are retracted, and the screw cores 10 and 10 are reversely rotated to remove them from the joint body 3.

At the tip of the nozzle of the injection machine 29,
When the nozzle of the injection machine 29 moves backward, the spool S also has a tip bulge, and the hooking protrusion of this bulge engages with the base end of the spool S (see FIG. 6) in the spool hole 17. As shown in FIG. 6, it is pulled out from the spool hole 17.

When the spool S is pulled out,
The plastic piece G in the discharge nozzle hole 18 is cut at the end portion on the side of the cavity 22 without being cut at the end portion on the spool S side. Never remains. Since the discharge nozzle hole 18 is inclined at a predetermined inclination angle θ _{2 with} respect to the spool axis Os, a larger shearing force acts on the end on the cavity 22 side than the end on the spool S side. Because it does. In this way, the core portion 8
No burr on the inner surface of the.

After that, when the turntable 26 is further rotated to return to the original first station, the corrosion resistant pipe joint 1 having the inner core portion 8 molded therein (as a finished product) is removed, and another joint is again formed. The main body 3 is set.

It should be noted that the mold jigs shown in FIGS. 2 to 6 are examples, and the inner core portion may be injection-molded using other mold jigs. Also, FIG. 7 is only an example,
The number of stations can be increased or decreased within the range of 3-8.
In addition, there are two types of pipe fittings molded in FIG.
There is no restriction on the type, and in that case, the same injection conditions will only exist in the 360 degrees of the turntable.

[0043]

The present invention has the following significant effects with the above-mentioned configuration.

It has become possible (according to claims 1, 2 and 3) to efficiently produce a large number of types of pipe joints in small quantities. Moreover, one worker is possible. This is convenient because the inefficiency of playing the device is eliminated.

Since the inner core portion 8 is injection-molded under the optimum injection conditions (according to claims 1, 2 and 3),
(Even in high-mix low-volume production) Quality is stable and excellent.

(According to the second and third aspects), the control of the injection condition is simplified.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a corrosion-resistant pipe joint manufactured according to the present invention.

FIG. 2 is an explanatory diagram of a process of a first station.

FIG. 3 is an explanatory diagram of a state immediately after completion of a process of the first station.

FIG. 4 is an explanatory diagram of a process of a second station.

FIG. 5 is an explanatory diagram of a process of the third station.

FIG. 6 is an explanatory diagram of a process of the fourth station.

FIG. 7 is a structural explanatory view showing an embodiment of the present invention.

[Explanation of symbols]

 3 Metal joint body 8 Inner core 26 Turntable 27 Joint body holder 29 Injection machine 31 Control means 32 Detector 33 Reference part for detection

Claims (3)

[Claims] 1. A set of metal joint bodies 3 of different types are set on one turntable 26, and the turntable 26 is intermittently rotated to sequentially stop at a plurality of stations. In one of the injection molding stations, a joint molding method is characterized in that molten plastic is injected under an injection condition corresponding to the type of the joint body 3 to mold the inner core portion 8. 2. A reference part 33 for detection is attached to one place around the turntable 26, and the reference part 33 is detected by a detector 32 on the fixed side, and further, a metal joint of a different type. The main body 3 is set in the circumferential direction from the reference portion 33 in a predetermined order and intermittently sent to the injection molding station, and the joint main body corresponding to the injection molding station by the detection signal from the detector 32. 3. The joint molding method according to claim 1, wherein the molten plastic is injected under the injection conditions corresponding to the identification No. 3. 3. A turntable 26 that intermittently repeats rotation stop and a plurality of joint body holders 27 provided on the turntable 26 so that two or more different types of metal joint bodies 3 can be set. ..., a station arranged around the turntable 26, and installed in one of the injection molding stations of the station to inject molten plastic into the joint body 3 to mold the inner core portion 8. A joint molding apparatus, comprising: an injection machine 29 for controlling the injection machine 29; and a control means 31 for controlling the injection machine 29 under injection conditions corresponding to the type of the joint body 3 that has come to the injection molding station.