JP2994221B2 - Mixing head of reaction injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixing head for a reaction injection molding machine, and more particularly, to a mixing head for mixing two or more undiluted solutions and simultaneously supplying a toner for coloring into the mixed solution. In particular, the present invention relates to a technique for preventing the formation of residual scum of a mixed liquid in a toner supply passage.

2. Description of the Related Art FIGS. 1 (I), (II), 2 (I) and 2 (II) show a conventional example of a mixing head of a reaction injection molding machine of this kind. The mixing head exemplified here is for producing a colored urethane foaming agent, and uses a water-containing polyol and an isocyanate as stock solutions. FIG. 1 (I) shows a first step in which the undiluted solution and the toner are filled into the second mixing chamber 11 through the first mixing chamber 4 while being mixed. FIG. 1 (II)
A second step in which the port opening / closing piston 3 is pushed down after the second mixing chamber 11 is filled with a predetermined amount of the mixed liquid is shown. FIG. 2I is a longitudinal sectional view of FIG.
(II) is an enlarged front view of the port opening / closing piston.

In this mixing head, a mixing block 2 is fixed to a front end of a cylinder body 1 and a head tip member 12 is fixed to a front end of the mixing block 2. The head end member 12 constitutes a connecting means for a mold (not shown).

[0003] The mixing block 2 has a first mixing chamber 4 and a second mixing chamber 11. The first mixing chamber 4 extends in the vertical direction and in a cylindrical shape, while the second mixing chamber 11 extends in a horizontal direction orthogonal to the first mixing chamber 4 in a cylindrical shape. The lower end of the first mixing chamber 4 is open to the second mixing chamber 11. Two undiluted solution discharge ports 5 are provided on the inner peripheral surface of the first mixing chamber 4.
c is open. That is, as shown in FIG. 2 (I), the mixing block 2 is provided with a pair of undiluted solution supply nozzles 5a and 5b, and the undiluted solution discharge ports 5c of the nozzles are respectively provided on the inner periphery of the first mixing chamber 4. It is open facing the surface. One nozzle 5a is supplied with a stock solution of isocyanate, and one nozzle 5b is supplied with a stock solution of a polyol containing water.

A port opening / closing piston 3 that slides up and down is inserted into the first mixing chamber 4. This piston 3
In the open position shown in FIG. 1 (I), that is, at the raised position, the pair of undiluted solution discharge ports 5c is open. on the other hand,
As shown in FIG. 1 (II), when the piston 3 is in the closed position, that is, the lowered position, the pair of ports 5c are closed to shut off the supply of the stock solution. Although not described in detail, the drive mechanism of the piston 3 is driven by switching hydraulic pressure or air pressure to a pressure chamber formed in the cylinder 8 shown in FIG.

A supply passage 6 for supplying a coloring toner is formed in the piston 3 in a vertical direction, and a toner discharge port 6a is opened on the lower surface of the piston 3.
The upper end of the passage 6 is bent in an L shape and communicates with a toner receiving port 6b formed on the outer peripheral surface of the piston 3.
The toner receiving port 6b is connected to the cylinder block 2
Is connected to a toner supply port 7 formed at a predetermined position. The toner supply port 7 is connected to a toner supply device (not shown). 1 (I), (II) and FIG.
As shown in (II), the toner supply passage 6 extends along the center axis of the piston 3, that is, just through the center of the piston 3. Therefore, the toner discharge port 6
a is also located at the center in the radial direction of the piston 3 as well shown in FIG.

On the other hand, a cleaning piston 10 that slides in the front-rear direction, that is, in the horizontal direction, is inserted into the second mixing chamber 11. This cleaning piston 10
Is for extruding the mixed liquid filled in the second mixing chamber 11 through the first mixing chamber 4 into a mold (not shown). Incidentally, reference numeral 9 in the figure denotes a screw type maintenance cock for accessing the inside of the second mixing chamber 11.

Next, the operation of the above-structured mixing head will be described.

First, in the first step shown in FIG. 1 (I), each stock solution of isocyanate and polyol is supplied into the first mixing chamber 4 from each stock solution discharge port 5c. At the same time, coloring toner is supplied from the toner supply passage 6 into the first mixing chamber 4. At this time, the tip of the cleaning piston 10 is
It is advanced to a position where a small stop 2c is formed between the mixing chamber 4 and the second mixing chamber 11.
In the figure, the front end of the cleaning piston 10 is the first end.
The position is further forward than the center of the mixing chamber 4. The reason why the throttle 2c is formed in this way is that the mixing effect is further improved by passing the mixture under a large pressure through the throttle 2c. The mixed liquid supplied into the first mixing chamber 4 is sufficiently mixed through the throttle 2c and filled into the second mixing chamber 11.
When the predetermined filling is completed, the process proceeds to the second step. In the second step, as shown in FIG. 1 (II), the port opening / closing piston 3 is pushed down to the lowermost end. At this time, the connection between the toner receiving port 6b and the toner supply port 7 is disconnected. Also, the stock solution discharge ports 5c are closed by the outer peripheral surface of the piston 3.

However, very inconvenient things occur in this second step. That is, when the piston 3 descends to the lowermost end, the space of the first mixing chamber 4 becomes narrower, and the portion of the throttle 2 c tends to be closed by the lower surface of the piston 3. Rises, and the mixed liquid flows back into the toner discharge port 6a, and remains as a residue 13. After the mixed liquid in the second mixing chamber 11 is discharged by the cleaning piston 10, the remaining residue 13 is trapped until the next cycle is started, during which the hardening starts, and this becomes a foreign substance in the mixed liquid. It remains. If such foreign matter appears on the surface of the molded article, it may cause very inconvenience depending on the use of the molded article, and may result in a defective article.

[0010]

SUMMARY OF THE INVENTION Accordingly, a technical problem to be solved by the present invention is to prevent a mixed liquid from flowing back into a toner supply passage in a mixing head of a reaction injection molding machine of this kind. Is to prevent the generation of residual residue.

[0011]

In order to solve the above technical problems, the present invention provides two solutions.

The basic structure of the mixing head according to the first solving means is the same as that of the conventional example shown in FIG. That is, the overall configuration includes a cylindrical first mixing chamber having a plurality of undiluted liquid discharge ports opened on the inner peripheral surface thereof, and a cylindrical second mixing chamber extending in a direction orthogonal to the first mixing chamber and communicating therewith. A mixing block having an opening position for opening the stock solution discharge port and securing the space of the first mixing chamber by sliding in the first mixing chamber, and a port for closing the stock solution discharge port and filling the space of the first mixing chamber. An opening / closing piston, and a cleaning piston that slides back and forth in the second mixing chamber to push out a mixed liquid supplied from the first mixing chamber into the second mixing chamber into a mold, and further includes a cleaning piston. The color toner is supplied at the same time as the stock solution is discharged.

In the mixing head according to the present invention, the toner supply passage is formed inside the port opening / closing piston, the toner discharge port is opened on the end face of the piston, and the opening position is defined by the cleaning piston. Is shifted forward in the sliding direction.

According to the above configuration, the first step of the operation is substantially the same as the first step of the conventional device. On the other hand, in the second step, when the port opening / closing piston 3 descends, the toner ejection port formed so as to be deviated forward is always facing the second mixing chamber, that is, in communication with the second mixing chamber. Even when it comes to the position, a pressure for causing the mixed liquid to flow backward to the toner discharge port is hardly generated.

In this manner, with a simple configuration in which the position of the toner discharge port is slightly shifted, the generation of residual dust in the toner discharge port, which has been a very problem in the past, can be effectively prevented. It is.

The first solution is to prevent the mixed liquid from flowing backward by changing the opening position of the toner discharge port. The second solution is basically the first solution and its method. To be different. That is, according to the second solution, the port opening / closing piston closes the toner discharge port immediately before and after the closing of the undiluted solution discharge port, thereby closing all the ports at an early stage of the downward movement of the piston and causing the reverse flow of the mixed liquid. It is to prevent.

The overall configuration of the mixing head according to the second aspect is exactly the same as the overall configuration of the first aspect. According to the second solution, the toner supply passage is formed inside the mixing block,
The toner discharge port is opened on the inner peripheral surface of the first mixing chamber and in the vicinity of the undiluted liquid discharge port.

According to the above configuration, the toner discharge port is opened at a position close to the stock solution discharge port. Therefore, when the port opening / closing piston is lowered, the toner discharge port is closed immediately before and after the stock solution discharge port is closed. As a result, the backflow of the mixed liquid into the toner discharge port is completely prevented regardless of the position of the cleaning piston and the increased space pressure in the first mixing chamber. is there.

[0019]

Embodiments of the present invention will be described below in detail with reference to FIG. 2 (III) and FIGS.

First, a first embodiment will be described with reference to FIG. 2 (III) and FIGS. 3 (I) and 3 (II). Since the basic configuration of the mixing head is substantially the same as the basic configuration of the conventional example shown in FIGS. 1 and 2, the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

This embodiment is basically different from the above-mentioned conventional example in the configuration of the toner supply passage 6 formed in the port opening / closing piston 3 and the toner discharge port 6a thereof.
That is, the toner supply passage 6 is formed so as to be deviated forward of the cleaning piston 10 in the sliding direction with respect to the center line of the port opening / closing piston 3. The opening position of the toner discharge port 6a is related to the position of the stop 2c formed by the cleaning piston 10. The position of the stop 2c that is in full communication with the open position and the closed position is the same. preferable. When the toner discharge port 6a is formed at this position, the toner discharge port 6a is always open even if the port opening / closing piston 3 is moved to the closed position, that is, the lowered position. The mixed liquid in the inner space 4 is pressure-fed into the second mixing chamber 11 without flowing back into the toner discharge port 6a. Therefore,
No residue of the mixed liquid remains in the toner discharge port 6a.

Next, according to FIGS. 4 (I) and (II), the second
An embodiment will be described. The basic configuration of the second embodiment is also shown in FIG.
Is substantially the same as that of the conventional example, the same parts are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the toner supply passage 1
4 is not formed in the port opening / closing piston 3, but is formed in the mixing block 2 instead. In other words, the toner supply path 14 is
It is formed in parallel with the mixing chamber 4 and its upper end communicates with the toner supply port 7, while the lower end of the toner discharge port 14 a is located on the inner peripheral surface of the first mixing chamber 4 and slightly above each raw liquid discharge port 5 c. It is open to. Reference numeral 15 denotes a screw-shaped maintenance plug provided to access the toner discharge port 14a from outside the mixing block 2.

According to this structure, in the first step, as in the case of the conventional example and the first embodiment, the stock solution is supplied into the first mixing chamber 4 through the stock solution discharge ports 5c and the toner is discharged. The toner can be supplied through the port 6a, and the mixed liquid mixed therein is filled into the second mixing chamber 11 through the throttle 2c.

On the other hand, in the second step, when the port opening / closing piston 3 starts to descend, the toner discharge port 14a is first closed on the outer peripheral surface of the piston 3, and then the undiluted liquid discharge ports 5c are closed. Then, the mixed liquid remaining in the first mixing chamber 4 is entirely discharged into the second mixing chamber 11.

Also in the second embodiment, since the toner discharge port 14a is completely closed at an early stage of the second step, a situation in which the mixed liquid flows back into the toner discharge port 14a does not occur.

As described above, the desired object of the present invention can be achieved by any of the embodiments.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a mixing head of a reaction injection molding machine according to a conventional example. (I) shows the first step of supplying the stock solution and the toner into the mixing chamber.
(II) shows the second step in which the port opening / closing piston is lowered to close each stock solution discharge port.

FIG. 2 (I) is a longitudinal sectional view of FIG. 1 (II). (II)
FIG. 2 is an enlarged front view of a port opening / closing piston included in the mixing head shown in FIG. 1. (III) is an enlarged front view of the port opening / closing piston according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a mixing head of the reaction injection molding machine according to the first embodiment of the present invention. (I) shows a first step of charging the stock solution and the toner into the mixing chamber. (II) shows the second step in which the port opening / closing piston is lowered to close each stock solution discharge port.

FIG. 4 is a sectional view of a main part of a mixing head of a reaction injection molding machine according to a second embodiment of the present invention. (I) shows a first step of charging the stock solution and the toner into the mixing chamber. (II) shows a second step of lowering the port opening / closing piston to close the toner discharge port and each stock solution discharge port.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder main body 2 ... Mixing block 2c ... Throttle 3 ... Port opening / closing piston 4 ... First mixing chamber 5a, 5b ... Stock solution supply nozzle 5c ... Stock solution discharge port 6 ... Toner supply passage 6a ... Toner discharge port 6b ... Toner receiving port 7 ... Toner supply port 8 ... Cylinder 9 ... Maintenance plug 10 ... Cleaning piston 11 ... Second mixing chamber 12 ... Head tip member 13 ... Remaining residue 14 ... Toner supply passage 14a ... Toner discharge port 15 ... Maintenance plug

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Claims (2)

(57) [Claims] A plurality of undiluted liquid discharge ports (5c) extend in a direction orthogonal to the first cylindrical mixing chamber (4), which is open on the inner peripheral surface thereof, and communicate with the first mixing chamber (4). Cylindrical second
A mixing block (2) having a mixing chamber (11);
Slides in the first mixing chamber (4) to discharge the undiluted solution.
(5c) an opening position for opening the first mixing chamber (4) and securing a space for the first mixing chamber (4); a port opening / closing piston (3) for closing the undiluted solution discharge port (5c) and filling the space of the first mixing chamber (4); Sliding in the front and rear direction in the second mixing chamber (11),
A cleaning piston that pushes the mixture supplied from the mixing chamber (4) into the second mixing chamber (11) into the mold.
In the mixing head of the reaction injection molding machine configured to supply the coloring toner simultaneously with the discharge of the undiluted solution, a toner supply passage (6) is provided in the first mixing chamber (4). It is formed inside the port opening / closing piston (3), and its toner discharge port (6a) is opened to the end face of the piston, and its opening position is displaced forward in the sliding direction of the cleaning piston (10). And mixing head. 2. A plurality of undiluted liquid discharge ports (5c) extend in a direction orthogonal to the first cylindrical mixing chamber (4) having an open inner peripheral surface and communicate with the first mixing chamber (4). Cylindrical second
A mixing block (2) having a mixing chamber (11);
Slides in the first mixing chamber (4) to discharge the undiluted solution.
(5c) an opening position for opening the first mixing chamber (4) and securing a space for the first mixing chamber (4); a port opening / closing piston (3) for closing the undiluted solution discharge port (5c) and filling the space of the first mixing chamber (4); Sliding in the front and rear direction in the second mixing chamber (11),
A cleaning piston that pushes the mixture supplied from the mixing chamber (4) into the second mixing chamber (11) into the mold.
Further, in the first mixing chamber (4), a mixing head of a reaction injection molding machine configured to supply a coloring toner at the same time as discharging the undiluted solution is provided with a toner supply passage (14). It is formed inside the mixing block (2), and its toner discharge port (14a) is formed on the inner peripheral surface of the first mixing chamber (4) and at the undiluted liquid discharge port.
(5c) A mixing head having an opening in the vicinity of (5c).