JPH051373Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a liquid pigment supply device for an injection molding machine.

(Prior art) As a liquid pigment supply device in a conventional injection molding machine, a normally open supply port is provided in a heating cylinder in front of a raw resin hopper, and a pump is used to forcefully feed liquid pigment as necessary. It is true. However, with this device, the pump was stopped when the supply of liquid pigment was interrupted, so the molten resin raw material flowed back from the liquid pigment supply port and solidified, making subsequent pigment supply impossible. .

Therefore, the present applicant previously proposed a structure of a liquid pigment supply section that includes a valve member supported by an elastic member that allows the liquid pigment supply port to be opened and closed freely (No. 53715/1983). ). This prior invention has the excellent effect of reliably preventing backflow of the resin raw material when the supply of liquid pigment is interrupted by opening and closing the valve member, but it uses a needle valve operated by spring pressure. It is necessary to raise the operating pressure of the valve sufficiently, and stable control may be difficult if the discharge amount is small, and the small hole-shaped supply port at the tip of the needle valve is easily clogged with raw resin. It was found that there were some problems.

(Problem to be solved by the invention) This invention solves the conventional problems mentioned above, allows stable control of even a small amount of discharge, and allows a wide range of molding conditions. This invention was proposed for the purpose of a liquid pigment supply device for an injection molding machine that can be enlarged and also reliably prevent clogging of the pigment supply port due to backflow of raw material resin.

(Means for Solving the Problems) That is, the liquid pigment supply device of this invention includes a valve body having an attachment part to a heating cylinder and an inflow part for the liquid pigment, and a valve body provided through the valve body through an inflow space for cooling air. and a sleeve having a liquid pigment spout formed through a tapered surface and a long hole on the inner peripheral tip side, and a sleeve that is fitted into the sleeve so as to be movable back and forth, and a tapered surface of the sleeve on the tip side. The valve rod has a valve portion consisting of a tapered portion that slides into contact with the sleeve and a long end portion that is the same length as the elongated hole portion of the sleeve and has a slightly smaller diameter, and an air cylinder device that moves the valve rod back and forth. .

(Example) Hereinafter, this invention will be explained in detail with reference to the illustrated embodiment. FIG. FIG. 2 is an enlarged sectional view of the valve portion in FIG. 1.

As shown in the figure, the liquid pigment supply device 10 of this invention includes a valve body 11, a sleeve 20 penetrating through the valve body 11, a valve rod 30 fitted into the sleeve 20 so as to be movable back and forth, and It is composed of various parts of an air cylinder device 40 that moves the valve rod 30 back and forth.

A valve body 11 of the liquid pigment supply device 10 has a threaded portion 12 for attaching the heating cylinder 9 to the valve body 11 . An inlet 13 for liquid pigment is formed in the upper part of the valve body 11 . code 1
4 is a check valve, and 14a is a spring. The valve body 11 also has a cooling air inflow space 19 formed by a cooling air inflow part 17 and a cooling air discharge part 18, as shown in the figure.

The sleeve 20 extends through the cooling air inlet space 19 of the valve body 11 . Note that the cooling air inflow space 19 is preferably formed over substantially the entire length of the sleeve 20. The upper end of this sleeve 20 communicates with the liquid pigment inflow section 13, and the lower end communicates with the heating cylinder 1.The inner peripheral tip of the sleeve 20 has a cylindrical structure as shown in FIG. A liquid pigment spout 25 is formed through the tapered surface 26 and the elongated hole 27 . In the embodiment, the elongated hole portion 27 is formed to have a diameter of about 10 mm.

The valve rod 30 is fitted into the sleeve 20 so as to be movable back and forth, and as shown in FIG. A valve portion 31 is formed with a long tip portion 33 having the same length as the elongated hole portion 27 and a slightly smaller diameter. Note that the gap between the long hole 27 of the sleeve 20 and the long end 33 of the valve rod 30 is approximately
It is adjusted to about 50μ.

The air cylinder device 40 is
0 and moves the valve rod 30 back and forth to open and close the pigment outlet 25. A stroke adjustment mechanism 41 is provided between the air cylinder device 40 and the valve rod 30, making it possible to adjust the stroke and operating pressure of the valve rod 30.

(Function) Next, to explain the operation of the liquid pigment supply device 10 of this invention, as shown in FIG. The sealing state between the section 32 and the tapered surface 26 of the sleeve 20 is released, and the liquid pigment supplied from the inflow section 13 flows through the tapered surface 26, the elongated hole section 27, and the long tip section 33.
It flows into the heating cylinder 9 from the spout 25 through a slight gap between the spout and the spout.

On the other hand, when the supply of liquid pigment is interrupted, the valve rod 30 is moved forward by the operation of the air cylinder 40 device, and the tapered portion 32 of the rod and the tapered surface 26 on the sleeve side are brought into close contact, thereby sealing the valve portion 31. In this case, since the elongated hole 27 leading to the spout 25 has the same length as the long tip 33 at the tip of the valve rod, it completely overlaps with the spout, the tip surfaces thereof coincide, and the gap between them is about 50μ. Since it is minute, the pigment inside the spout 25 is completely sent out to the outside, and the backflow of the resin raw material from the heating cylinder 9 is reliably prevented.

Furthermore, since this invention uses a forced shut-off system in which the opening and closing of the valve portion 31 is performed by the air cylinder 40, there is no need to increase the pigment supply pressure sufficiently high to operate the valve body, unlike in the past.
It is possible to stably control even a small amount of pigment to be poured out, and the valve part 31
It can correspond to any molding conditions without any response deviation.

Furthermore, since the valve body 11 is formed with a cooling air inflow space 19 to forcibly cool the outer peripheral surface of the sleeve 20, it is possible to completely prevent expansion and foaming of the oil in the pigment when it remains at high temperature. It is effective.

(Effects) As shown and explained above, according to this invented device, a forced cooling system is achieved by providing an inflow space for cooling air in the valve body, and a taper portion that slides the valve portion of the valve rod against the tapered surface of the sleeve and the sleeve The valve rod has a long tip with a diameter slightly smaller than the long hole, and the valve rod has a forced shut-off system using an air cylinder device.
It has become possible to stably control even when dispensing a small amount of liquid pigment.
This has made it possible to significantly expand the range of molding conditions. Furthermore, as mentioned above, with this invention, it is possible to reliably prevent pigment from remaining in the pigment spout and clogging of the pigment spout due to backflow of raw resin, thereby solving the conventional problems. We were able to provide a device with extremely high practical value as a liquid pigment supply device for an injection molding machine.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of a liquid pigment supply device which is an embodiment of this invention, and FIG. 2 is an enlarged cross-sectional view of the valve portion in FIG. 1. DESCRIPTION OF SYMBOLS 10... Liquid pigment supply device, 11... Valve body, 13... Liquid pigment inflow part, 19... Cooling air inflow space, 20... Sleeve, 25... Outlet, 26... Tapered surface, 27... Length Hole, 30...
... Valve rod, 31 ... Valve body, 32 ... Tapered portion, 33 ... Long tip, 40 ... Air cylinder.

Claims (1)

[Scope of Claim for Utility Model Registration] A valve body having an attachment part to a heating cylinder and an inflow part for liquid pigment, the valve body being penetrated through the valve body via an inflow space for cooling air, and having a tapered surface and a tapered surface on the inner peripheral end side. A sleeve having a liquid pigment spout formed through a long hole; a tapered portion that is fitted into the sleeve so as to be movable back and forth, and that slides into contact with a tapered surface of the sleeve on the distal end side; and a long hole of the sleeve. 1. A liquid pigment supply device for an injection molding machine, comprising: a valve rod having a valve portion having a long tip having the same length and a slightly smaller diameter; and an air cylinder device for moving the valve rod back and forth.