JPH0536211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is utilized in the technical field of plastic lens molding, and particularly relates to an apparatus for injecting a plastic raw material liquid into a mold using a taping method.

[Prior Art] Recently, plastic lenses have been widely used in eyeglasses and the like. A so-called taping method is known as a method for easily molding this plastic lens. This method involves preparing a pair of molds such as glass plates with one molding surface, placing the molding surfaces facing each other in a predetermined position, and then applying tape around the entire circumference of the pair of molds so as to span the peripheral surfaces of the pair of molds. A mold is made by winding the lens with adhesive, and a plastic raw material liquid to be polymerized, hardened, and molded is injected into the internal space formed between the two molds to mold the lens.

To inject the above-mentioned plastic raw material liquid, partially open the joined part of the adhesive tape wound around the mold, hold the mold with the opening facing upward, and insert the injection pipe into the opening. It was carried out by Then, the injection was stopped at a time when the liquid level of the plastic raw material liquid injected into the inner space of the mold just filled the opening.

[Problem to be solved by the invention]

However, with the above method, it is difficult to judge the injection level of the plastic raw material liquid and stop the injection so as to just fill the internal space, and if the injection is stopped too early, the liquid will run out and a small amount must be replenished again. However, if it is too slow, there is a problem that the plastic raw material liquid overflows and adheres to the surrounding area.

Furthermore, air bubbles may remain after the injection of the plastic raw material liquid is completed, which may cause molding defects.

The present invention solves the above-mentioned problems, and provides a spring for molding plastic lenses that can stop injection when the plastic raw material liquid just fills the inner space of the mold, and that does not leave any air bubbles. The purpose is to provide a raw material liquid injection device.

[Means to solve the problem]

According to the present invention, the above-mentioned object is provided in a tape joining part of a mold formed by adhesively winding a tape so as to span the peripheral surfaces of a pair of disc-shaped molds whose molding surfaces face each other with a predetermined interval. A stand for supporting the forming mold so that the opening is positioned above a vertical line, and a stand for injecting the plastic raw material liquid into the inner space of the mold from an injection opening that is filled with the plastic raw material liquid. An intake pipe with an intake port set in the opening at a surface level, an injection pipe for injecting a plastic raw material liquid and with an injection port set in the opening at a position below the intake port of the intake pipe, and an injection pipe in the intake pipe. This is achieved by including an injection stop means that detects an increase in negative pressure and stops the injection of the plastic raw material liquid from the injection pipe based on this detection.

[Effect]

According to the present invention as described above, when the plastic raw material liquid is injected into the inner space of the mold from the injection pipe and the liquid level rises at the opening, the liquid level blocks the intake port of the intake pipe, so that the negative pressure in the intake pipe is reduced. Based on this, the injection stop means stops the injection of the plastic raw material liquid from the injection pipe. At this time, since the air in the internal space of the mold is sucked through the intake port until just before the liquid level closes the intake port, no air bubbles remain.

The mold filled with just enough plastic raw material liquid is taken out and the opening is sealed again with tape, and the plastic raw material liquid polymerizes and hardens to complete the molding.

〔Example〕

Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a schematic configuration diagram of the apparatus of this embodiment, FIG. 2 is a cross-sectional view along the line taken from FIG. 1, and FIG. 3 is a perspective view of the portion shown in FIG. 2.

In the figure, 1 is a stand consisting of two upright parallel plates 1A connected by two triangular blocks 1B.
V-shaped upper surface 1 formed by the triangular block 1B
B' and the inner surface 1A' of the upright parallel plate 1A support the mold.

The mold 2 supported by the stand 1 includes a pair of disc-shaped molds 2 facing each other with a predetermined distance between them.
A tape 2C is adhesively wound around the entire circumference of the molds 2A and 2B so as to span both molds 2A and 2B, and an internal space is formed in the circular part for injecting a plastic liquid that will become a plastic lens. There is. In this embodiment, a small opening 2D for injecting the plastic raw material liquid is formed by peeling off a portion of the tape 2C at the joint portion of the tape 2C (see FIG. 3).

An injection pipe 3 and an intake pipe 3 for injecting plastic raw material liquid are arranged above the mold 2. The intake port 4A at the lower end of the intake pipe 4 is positioned at the level of the opening 2D, that is, at the level of the liquid level when the interior space of the mold 2 is filled with plastic raw material liquid. The injection pipe 3 is positioned such that the injection port 3A at its lower end is located below the intake port 4A.

The injection pipe 3 and the intake pipe 4 are held together by a band 5A, and a reference piece 5B is attached.
A) By abutting against the circumferential surface of the intake pipe 4,
The air intake port 4A is positioned accurately at the height level of the opening 2D. Further, a holding member 6 is attached to the injection pipe 3 and the intake pipe 4. The holding member 6 is guided by an immovable shaft 7 so as to be vertically slidable. A stopper 7A is provided at the lower end of the shaft 7, and a compression spring 8 is disposed between the holding member 6 and the mounting portion of the shaft.

The injection pipe 3 has a control valve 9 that shuts off the flow path of the injection pipe 3 in response to a command from a pressure gauge with a setting point, which will be described later.
is attached, and together with the above-mentioned pressure gauge with setting point, constitutes an injection stop means.

On the other hand, the suction pipe 4 is connected to suction means such as a vacuum device (not shown) via a sealed liquid receiving container 10. The intake pipe 4 is connected to the upper part of the liquid receiving container 10, and a drain valve 11 is attached to the lower end of the liquid receiving container 10. Further, on the outlet side of the liquid receiving container 10, the intake pipe 4 is provided with a restriction orifice 12 for allowing only gas to pass through and for increasing pressure fluctuations. The liquid receiving container 10 is controlled by the pressure inside the intake pipe 4, that is, the liquid receiving container 1
The pressure gauge 13 is connected to the control valve 9 through a pressure gauge 13 with a setting point that issues a signal to close the control valve 9 when the negative pressure within the pressure increases beyond a set value. The set point pressure gauge 13 can change the set value as appropriate.

In the apparatus of this embodiment as described above, the plastic raw material liquid is injected in the following manner.

First, the mold 2 having the opening 2D as shown in FIG. 3 is supported on the stand 1 while the holding member 6 is lifted to raise the injection pipe 3 and the intake pipe 4. As shown in FIG.

Next, the plastic raw material liquid is injected from the injection pipe 3 into the inner space of the mold. At that time, the intake pipe 4
is taking air from the intake port 4A.

As the injection progresses, the liquid level of the plastic raw material liquid in the internal space rises and reaches the intake port 4A of the intake pipe 4, thereby blocking the intake port 4A. Intake port 4
The negative pressure inside the intake pipe 4 where A is blocked, that is, the negative pressure inside the liquid receiving container 10, increases rapidly.

The sudden change in the negative pressure mentioned above is caused by the pressure gauge 13 with the setting point.
If the value exceeds the set value, the pressure gauge 13 with a setting point issues a command to the valve 9, which is closed and the injection of the plastic raw material liquid is stopped. Thus,
When the injection pipe 3 and the suction pipe 4 are lifted up to take out the mold 2, the plastic raw material liquid stops at a level that just fills the internal space of the mold 2. Thereafter, the mold is taken out and the opening 2D is sealed with tape 2C.

The plastic raw material liquid sucked in small quantities through the suction pipe 4 when the suction port 4A is closed is stored in the liquid receiving container 10 and discharged from the drain valve 11 at an appropriate time.

〔Effect of the invention〕

The present invention is as described above, and when the plastic raw material liquid is injected into the mold, it is filled with just the right amount of liquid, so there is no residual air bubbles or overflow of the plastic raw material liquid, and the molded plastic lens is It is possible to improve quality and work efficiency.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of the apparatus of this embodiment, FIG. 2 is a cross-sectional view along the line taken from FIG. 1, and FIG. 3 is a perspective view of the portion shown in FIG. 2. 1...Stand, 2...Mold, 2A, 2B...
...mold, 2C...tape, 2D...opening, 3
... Injection pipe, 3A ... Inlet, 4 ... Intake pipe, 4
A... Intake port, 9, 13... Injection stop means (9...
...Control valve, 13...Pressure gauge with setting point).

Claims (1)

[Scope of Claims] 1. An injection device provided at the tape joining part of a mold, which is formed by winding a tape with adhesive so as to span the peripheral surfaces of a pair of disc-shaped molds whose molding surfaces face each other with a predetermined interval. A stand that supports the mold so that the opening is positioned above the vertical line, and a stand that injects the plastic raw material liquid into the internal space of the mold from an opening, and a stand that supports the mold with the opening positioned above the vertical line, and a stand that supports the mold with the liquid level when filled with the plastic raw liquid. An intake pipe having an intake port set in the opening; an injection pipe for injecting a plastic raw material liquid and having an injection port set in the opening at a position below the intake port of the intake pipe; and an increase in negative pressure in the intake pipe. A plastic raw material liquid injector for molding a plastic lens, characterized in that it is equipped with an injection stop means for detecting and stopping the injection of the plastic raw material liquid from the injection pipe based on the detection.