JPH0221212Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention involves colliding and mixing multiple liquid plastic raw materials (hereinafter referred to as stock solutions) at high pressure, feeding them into a mold, and molding plastic products through a chemical reaction. This invention relates to a mixing head for a reaction injection molding machine.

``Prior Art'' Conventionally, in a reaction injection molding machine, as shown in FIG. 3 and 3 to the mixing head 4, and during injection, they are collided with each other in the mixing head 4 and injected into the mold, and when not injected, they are sent from each supply pipe 3, 3 via the mixing head 4, or to the mixing head. The stock solution is circulated to each stock solution tank 1, 1 through each return pipe 6, 6 via each bypass pipe 5, 5 without passing through 4. As shown in FIGS. 4 to 6, the mixing head 4 can be detachably attached to a head body 8 to which a hydraulic cylinder 7 is connected, and bolts 9 to the left and right sides of the head body 8. The head main body 8 is formed with a sliding hole 11 with a mixing chamber 11a near its tip, and the hydraulic cylinder 7 is inserted into the sliding hole 11 to form a mixing chamber 11a. A spool 12 that can be moved in the axial direction is fitted.
Further, the supply pipes 3, 3 and the return pipes 6, 6 (consisting of pipes and hoses) are screwed and connected to each of the blocks 10, 10, and the inside of each block 10, 10 is , respective supply passages 13, 13 communicating with the respective supply pipes 3, 3 and respective return passages 14, 14 communicating with the respective return pipes 6, 6 are formed in the head main body 8. Each injection nozzle (injection path) 15, 15 injects each stock solution sent from the supply paths 13, 13 into the mixing chamber 11a of the sliding hole 11 at the time of injection, and the circulation groove 16 of the spool 12 at the time of non-injection, Each circulation path 17, 17 returns to each return path 14, 14 via 16 etc.
is formed.

In the figure, 18 is a switching valve, 19 is a hydraulic unit, 20 is a heat exchanger, and 21 is a temperature control device.

"Problems to be Solved by the Invention" By the way, in the mixing head 4, depending on the molding conditions, each injection nozzle 15, 15 may be replaced in order to change the injection pressure of each stock solution, or the head main body 8 may be replaced. Other internal parts need to be replaced or inspected. In such a case, each block 10, 10 is removed from the head body 8 by loosening the bolt 9, but at that time, the head body 8, blocks 10,
10 and the stock solution inside each of the supply pipes 3, 3 and return pipes 6, 6 will flow out to the outside. From the head main body 8 and blocks 10, 10, each flow path is short and the cross section of the flow path is small, so only a small amount of stock solution flows out, but from the supply pipes 3, 3 and the return pipes 6, 6, the pipes are long and the flow paths Since the cross section is large, a large amount of raw liquid flows out. This leakage of the stock solution must be prevented as much as possible for the following reasons.

(1) Generally, the undiluted solution is harmful to humans.

(2) Isocyanates for urethane molding tend to react with moisture in the air and solidify.

(3) The stock solution for nylon molding is often handled at around 100℃, and spilling it can cause burns.

(4) Caprolactam in the stock solution for nylon molding has a melting point of approximately 69°C, and if it flows out and is cooled, it will solidify on the spot.

(5) The spilled undiluted solution will be discarded, resulting in a loss.

(6) If the undiluted solution spills, work efficiency will decrease, the working environment will be poor, and it is necessary to clean up the spilled undiluted solution.

This invention was made in view of the above circumstances,
The object of the present invention is to provide a mixing head for a reaction injection molding machine that prevents the undiluted solution from flowing out when the block is removed, thereby eliminating the various problems described above caused by the undiluted solution flowing out.

``Means for Solving the Problems'' In order to achieve the above object, the present invention provides a head body in which a spool is slidably fitted in a sliding hole in a liquid-tight manner, and a supply pipe for stock solution and a return pipe for return. A block connected to the pipe is removably attached, and the block is provided with a supply passage communicating with the supply pipe and a return passage communicating with the return pipe,
The head body is formed with an injection path for injecting the stock solution sent from the supply path into the mixing chamber of the sliding hole during injection, and a circulation path for returning the stock solution to the return path during non-injection. In the mixing head of the molding machine, the block is provided with a supply passage opening/closing valve for opening and closing the supply passage and a return passage opening/closing valve for opening and closing the return passage.

"Function" In the mixing head of the present invention, the supply passage opening/closing valve and the return passage opening/closing valve are kept open when the reaction injection molding machine is in operation, and when the mixing head is disassembled when stopped, the abovementioned opening/closing valve is kept open. Each on-off valve is closed and the block is removed from the head body, thereby preventing a large amount of stock solution in the supply pipe and return pipe from flowing out.

"Embodiment" An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that parts having the same basic structure as those of the conventional example are given the same reference numerals as those of the conventional example, and the explanation thereof will be omitted.

In this embodiment, each supply path 13 of each block 10 has a screw hole at one end 13a opened at a predetermined portion of the rear surface 10a of each block 10, and the other end 13b communicates with each injection nozzle 15, as in the conventional case. The other end 13b extends coaxially with each injection nozzle 15, and is bent rearward at the center of each block 10 to form a bent portion 13c. Further, each block 10 has a circular cross section with a diameter larger than the diameter of the other end 13b of each supply channel 13, and the bent portion 13c of each supply channel 13 is extended coaxially with each injection nozzle 15. Each mounting hole 22 is formed to extend and open to the side surface 10b of each block 10, and a female threaded portion 22a is formed at the open end side of each mounting hole 22.

Each of the supply passage opening/closing valves 23 has a conical portion 23a at the tip thereof, a threaded portion 23b at the proximal end, and an O-ring 23c fitted into a groove in the intermediate portion of each of the mounting holes 22. However, the conical part 2
3a facing the bending part 13c of each supply passage 13, and its male threaded part 23b is screwed to the female threaded part 22a to be detachably attached. When the conical portion 23a is brought into contact with the stepped portion 13d at the boundary between the mounting hole 22 and the other end 13b of the supply path 13, each supply path 13 is shut off, and each supply path opening/closing valve 23 is loosened to close the conical portion 23a.
When separated from the stepped portion 13d, each supply path 1
3 is in a communicating state. Further, on the side surface 10b of each block 10, each stopper 24 is screwed onto each on-off valve 23, and the head 23d at the base end of each supply passage on-off valve 23 comes into contact with the stopper 24 when the on-off valve 23 is loosened. .

On the other hand, each return path 14 of each block 10 has one end 14a with a screw hole opened at the rear surface of each block 10, the other end 14b communicated with each circulation path 17 of the head main body 8, and the other end 14b
The side extends coaxially to each circulation path 17, and each block 1
0 bends downward at the inner center of the bent part 1
4c is formed. In addition, each block 10 is provided with each return path 1 as well as each mounting hole 22 described above.
4, the bent portion 14c of each return path 14 is connected to each circulation path 1.
Mounting holes 25 are formed which extend coaxially with the block 7 and open at the side surface 10b of each block 10, and each mounting hole 25 also has a female threaded portion 25a formed at its open end.

Each of the mounting holes 25 has a conical portion 26a at the tip, a threaded portion 26b at the base end, and an O-ring 26c is attached to the intermediate portion, similar to each of the supply path on/off valves 23. Each return path opening/closing valve 26
However, the conical part 26a faces the bent part 14c, and the threaded part 26b is screwed into the female threaded part 25a to be detachably attached.
When a is brought into contact with the step 14d at the boundary between the mounting hole 25 and the other end 14b of the return path 14, each return path 14 is blocked, and when the conical portion 26a is separated from the step 14d, each return path is closed. 14 is in communication. Further, on each side surface 10b of each block 10, similar to each stopper 24,
Each stopper 27, which the head 26d of each return passage opening/closing valve 26 hits when it is loosened, is screwed and attached to each opening/closing valve 26.

However, in the mixing head with the above configuration,
During normal operation, each supply path on-off valve 23 and each return path on-off valve 26 are loosened, and each supply path 13 and each return path 1 are
4 are connected to each other.

On the other hand, if it becomes necessary to disassemble the mixing head 4, first screw in each of the supply passage on-off valves 23 and each return passage on-off valve 26, and then screw in each of the conical portions 2.
3a and 26a are brought into contact with the step portions 13d and 14d of each supply path 13 and each return path 14, respectively, thereby blocking each supply path 13 and each return path 14. Then, loosen the bolts 9 and remove each block 10 in the same manner as before.
Remove it from the head body 8 and proceed with the work. At this time, even if each block 10 is removed from the head main body 8, each supply path 13 and each return path 14 are connected to each on-off valve 2.
3 and 26, only a small amount of stock solution accumulated inside the head main body 8 and inside the other ends 13b and 14b of the supply path 13 and return path 14 of each block 10 flows out to the outside. The large amount of stock solution in the supply pipe 3 and each return pipe 6 does not flow out. Therefore, there is almost no loss of stock solution, it is easy to clean up spilled stock solution, and the work environment can be maintained in a good condition.
Moreover, accidents such as burns can be easily prevented.

In this way, in the mixing head configured as described above, by closing each supply path 13 and each return path 14 with each supply path on-off valve 23 and each return path on-off valve 26, the outflow of the stock solution can be suppressed to an extremely small amount. Moreover, the opening and closing of each of the on-off valves 23 and 26 is as follows.
This can be easily done from the outside by simply screwing or loosening these.

In addition, in the mixing head having the above configuration, each stopper 24, 27 is provided on the side surface 10b of each block 10.
are attached so that when each on-off valve 23, 26 is loosened by an appropriate amount, each head 23d, 26d of the opening/closing valve 23, 26 comes into contact with each stopper 24, 27.
For this reason, each on-off valve 23,
There is no risk of loosening 26 too much. In addition, if the stoppers 24, 27 are not provided and the on-off valves 23, 26 are loosened too much, the male threaded portion 23 of each on-off valve 23, 26
b, 26b are hardly screwed into the female threaded portions 22a, 25a, and the excessive pressure of the stock solution acts on each on-off valve 23, 26 and tries to blow each on-off valve 23, 26 outward, but this stopper 24 ,2
7 prevents it from becoming too loose. Further, since each stopper 24, 27 also functions as a lock nut, each opening/closing valve 23, 26 is reliably locked.

``Effects of the invention'' As explained above, the mixing head of the invention has the following effects:
The block is provided with a supply path on-off valve and a return path on-off valve, and when the block is disassembled, the supply path and return path are closed by the above-mentioned on-off valves, so the outflow of the stock solution is suppressed to an extremely small amount. Therefore, there is almost no loss of the stock solution, a good working environment can be maintained, work efficiency is increased, and accidents such as burns can be easily prevented.

[Brief explanation of the drawing]

Figures 1 and 2 show one embodiment of the present invention. Figure 1A is a sectional view of the main part, Figure 1B is a cross-sectional view of the
Figure 2 is a cross-sectional front view of one block, Figure 3 is a flowchart of an injection molding machine, and Figures 4 to 6 are a diagram of a conventional mixing head. 4 is a sectional view of the main part, FIG. 5 is a front view showing one block in cross section, and FIG. 6 is a plan view. 3... Supply pipe, 6... Return pipe, 8... Head body, 10... Block, 11... Sliding hole, 12...
...Spool, 13... Supply path, 14... Return path,
15... Injection nozzle (injection path), 17... Circulation path,
23... Supply path on/off valve, 26... Return path on/off valve.

Claims (1)

[Scope of utility model registration request] A block to which a supply pipe and a return pipe for liquid plastic raw materials are connected is removably attached to the head body in which a spool is slidably fitted in a liquid-tight manner in a sliding hole, and a block is removably attached to the head body. , a supply passage communicating with the supply pipe and a return passage communicating with the return pipe, and the head main body includes:
A reaction injection molding machine having an injection path for injecting the liquid plastic raw material sent from the supply path into the mixing chamber of the sliding hole during injection, and a circulation path for returning the liquid plastic raw material to the return path during non-injection. A mixing head for a reaction injection molding machine, wherein the block is provided with a supply passage opening/closing valve for opening/closing the supply passage and a return passage opening/closing valve for opening/closing the return passage.