JPH0675871B2 - Mold release method and device for plastic lens - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mold releasing method and an apparatus for separating a plastic lens from an upper mold and a lower mold when forming a plastic lens.

"Prior art and its problems" For plastic lenses, a synthetic resin material to be polymerized is injected into a mold space composed of an upper mold, a lower mold and an annular gasket, and after curing, the gasket is first cut and removed, Next, the upper mold and the lower mold are manufactured by removing them from the plastic lens. In this manufacturing process, the work of removing the upper mold and the lower mold from the lens has conventionally been performed by inserting a wedge piece between the upper mold and the lower mold that simultaneously contacts both molds and applying an opening pressure. However, the method using the wedge piece cannot apply a uniform force to the upper die, the lower die and the molded lens, and in fact, only one of the upper die and the lower die comes out of the lens, and the other is separated. It was the actual situation that had to be removed. Also, an upper mold and a lower mold made of glass,
Utilizing the difference in coefficient of thermal expansion from a lens made of a synthetic resin material, a method of immersing in a temperature-controlled liquid tank is also proposed, but this method not only enlarges the equipment,
The task of separately collecting the separated mold and lens is complicated.

[Object of the Invention] The present invention is based on the problems of the conventional mold releasing method of a plastic lens, and a method capable of easily and reliably separating the molded plastic lens from the upper mold and the lower mold simultaneously. The purpose is to propose a device.

"Summary of the Invention" The present invention was made by discovering the fact that, when a mechanical compressive force is applied only to a plastic lens, the upper mold and the lower mold are simultaneously removed from the lens. Applying mechanical compressive forces to the product lens was taboo and never tried. The present invention has been completed with this blind spot.

That is, the present invention is a mold releasing method for a plastic lens in which a plastic lens is molded between an upper mold and a lower mold, and after molding, the upper mold and the lower mold are removed from the plastic lens,
A method for releasing a plastic lens is characterized in that a mechanical compressive force is applied to only the plastic lens from both ends in the radial direction to separate the upper mold and the lower mold from the plastic lens.

A mold releasing apparatus for carrying out the method of the present invention includes a pair of tables supported by a frame so as to be movable toward and away from each other, and an upper mold and a lower mold, which are respectively provided on the pair of tables, contact each other in a radial direction. The plastic lens is provided with an abutting body that does not come into contact with the plastic lens and comes into radial contact with the plastic lens; Is characterized by.

According to this device, the mold release can be performed without the risk of damaging the plastic lens.

One of the tables is composed of an elevating table which is moved up and down by an actuator, and the other is composed of a contact / separation table which is contacted / separated by another actuator.
The pressing body on the side of the contact / separation table is supported so that it can be contacted / separated with respect to the contact / separation table, and a switch means is provided which is activated when the pressing body is pushed into the contact / separation table. At this time, if the actuator on the lifting table side is turned on, the mold releasing work can be performed similarly even if the diameter of the plastic lens varies.

"Examples of the Invention" The present invention will be described below with reference to illustrated examples. FIG. 1 is a conceptual diagram for explaining the method of the present invention. The upper mold (front mold) 12 and the lower mold (back mold) 13 for manufacturing the plastic lens 11 are integrated on the front and back of the annular gasket 14, and the liquid to be polymerized from the injection port 14a formed in the gasket 14. The synthetic resin material is cast. After the synthetic resin material is cured, the gasket 14 is first peeled off. When the gasket 14 is peeled off, the upper mold 12 and the lower mold 13 are left in the bonded state on the front and back of the molded plastic lens 11.

According to the present invention, in order to separate the upper mold 12 and the lower mold 13 from the plastic lens 11, a mechanical compressive force P is applied to the plastic lens 11 in the radial direction. Then,
The plastic lens 11 shrinks by a small amount according to the compressive force P, but the upper mold 12 and the lower mold 13 do not shrink because such a force is not applied. For this reason, a difference in length occurs between the adhesive surfaces of the plastic lens 11 and the upper mold 12 and the lower mold 13. As a result, the upper mold 12 and the lower mold 13 are easily and simultaneously peeled off (separated from the plastic lens 11). Type). The compressive force P is determined within a range in which the plastic lens 11 is not destroyed and no distortion remains. According to experiments, the plastic lens 11 as a product is not adversely affected and the upper mold is not affected.
It was possible to separate the 12 and the lower mold 13.

The present invention does not ask how to apply the compressive force P to the plastic lens 11, but next, an embodiment of a mold releasing device that can easily and surely apply the compressive force P will be described with reference to FIGS. .

In the frame 21, a small cylinder device 22 is provided in the lower part in the vertical direction, and the piston body 22a has a small cylinder device 22,
The lifting table 23 is fixed. This lifting table 23
Can be moved by a small distance up and down in FIG. 2 by a small cylinder device 22. The orbitable distance of the lifting table 23 can be adjusted by the distance s between the adjusting screw 24 screwed to the piston body 23a and the fixed body 22b.

A lower contact bar 27 is supported on the elevating table 23 by a dovetail groove 26 so that the lower contact bar 27 can be inserted and removed in the horizontal direction. The lower contact bar 27 can be attached / detached to / from the lifting table 23 by a fixing screw 28. As the lower contact bar 27, a plurality of different shapes are easily prepared according to the width of the plastic lens 11 that is planned.

On the other hand, a swing arm 32 is pivotally attached to the upper portion of the frame 21 by a fixed shaft 31, and a contact / separation table 33 facing the lift table 23 is fixed to one end of the swing arm 32. . An upper contact bar 37 is supported on the contact / separation table 33 by a dovetail groove 36 so that the upper contact bar 37 can be inserted and removed in the horizontal direction. The upper contact bar 37 is located in the same plane as the lower contact bar 27.

The dovetail groove 36 is formed to allow a slight vertical movement of the upper contact bar 37, and the upper contact bar 37 is moved to the lower moving end between the upper contact bar 37 and the contact / separation table 33. A biasing spring plunger 34 is inserted. Further, the contact / separation table 33 is provided with a tactile switch 35 that detects when the upper contact bar 37 moves to the upper moving end against the force of the spring plunger 34. Upper contact bar
Like the lower contact bar 27 below, 37 can be attached / detached to / from the contact / separation table 33. The lower contact bar 27 and the upper contact bar 37 are formed in a shape (width) that contacts the plastic lens 11 in the radial direction but does not contact the upper mold 12 and the lower mold 13 in the radial direction.

The drive shaft 40 of the swing arm 32 is rotatably supported by the frame 21 below the fixed shaft 31. A peripheral surface cam (eccentric cam) 41 is integrally formed on the drive shaft 40, and the peripheral surface cam 41 is a downward extension arm of the swing arm 32.
It contacts the contact surface 32b of 32a. This peripheral cam 41 and contact surface 32
The compression spring 42 that urges the swing arm 32 to rotate is constantly in contact with b. Drive shaft 40 is SELEX rotary 43
When driven to rotate, the swing arm 32 swings around the fixed shaft 31 according to the shape of the peripheral cam 41, and the contact / separation table 33, that is, the upper contact bar 37 with respect to the lower contact bar 27. Approach and separate.

The mold releasing apparatus having the above structure operates as follows. Now, when the SELEX rotary 43 is in a stopped state, the peripheral cam 41 causes the upper contact bar 37 to move to the highest position,
Suppose 32 is down. In this state, the plastic lens 11 to which the upper mold 12 and the lower mold 13 are attached is inserted between the lower contact bar 27 and the upper contact bar 37. Here, when the SELEX rotary 43 is switched on, the drive shaft 40 rotates, the swing cam 32 swings by the peripheral surface cam 41, and the upper contact bar 37 descends with respect to the plastic lens 11. Then, the spring plunger 34 is compressed, and the upper contact bar 37 rises with respect to the contact / separation table 33. When the upper end bar 37 reaches the rising end, this is detected by the tactile switch 35. When the tactile switch 35 is turned on, the SELEX rotary 43 is stopped, and at the same time, the small cylinder device 22 is actuated and the lifting table 23 is started to be lifted.

When the lifting table 23, that is, the lower contact bar 27 is raised,
A compressive force P in the radial direction is applied to the plastic lens 11 sandwiched between the upper contact bar 37 and, as a result, the upper mold 12 and the lower mold 13 are separated from the plastic lens 11 at the same time according to the principle described in FIG. Mold. Since the maximum stroke of the lower contact bar 27 is regulated by the adjusting screw 24 screwed to the piston body 22a of the small cylinder device 22 and the fixed body 22b, an excessive force is applied to the plastic lens 11 after releasing the mold. It is possible to eliminate the risk of damage due to the addition of.

When the mold release is completed, the small cylinder device 22 and the SELEX rotary 43 are returned to their original positions and stopped to prepare for the next mold release operation. The end of the mold release can be detected, for example, when the piston body of the small cylinder device 22 reaches the rising end.

In the above-mentioned embodiment, since the upper contact bar 37 is displaceable with respect to the contact / separation table 33, there is a feature that it is possible to cope with variations in the diameter of the plastic lens 11. However, even if this table 33 is fixed, the device of the present invention can be realized.

The manual lever 39 provided on the swing arm 32 is for manually raising and lowering the arm.

[Advantage of the Invention] As described above, according to the method of the present invention, the upper mold and the lower mold attached to the plastic lens are simultaneously attached by a very simple method of applying a radial mechanical compression force to the plastic lens. It can be reliably released.

Further, according to the device of the present invention, only the plastic lens can be pressed by the abutting bodies provided on the pair of tables, and the maximum approaching position of the pair of tables is restricted, which may damage the plastic lens. Without, it is possible to reliably release the mold.

According to the third aspect, even if the diameter of the plastic lens varies, the releasing operation can be similarly performed.

[Brief description of drawings]

FIG. 1 is a sectional view showing the principle of a plastic lens releasing method according to the present invention, FIGS. 2 to 4 show an embodiment of a releasing apparatus of the present invention, and FIG. 2 is a longitudinal sectional view. 3 and 4 are sectional views taken along the lines III-III and IV-IV of FIG. 2, respectively. 11 …… Plastic lens, 12 …… Upper mold, 13 …… Lower mold,
14 …… Gasket, 14a …… Inlet, 21 …… Frame, 2
2 …… Small cylinder device (actuator), 23 …… Lift table, 24 …… Adjusting screw, 25 …… Stopper, 26 ……
Dovetail groove, 27 ... Lower contact bar (contact body), 28 ... Fixing screw, 31 ... Fixed shaft, 32 ... Swing arm, 33 ... Contact / separation table, 34 ... Spring plunger, 35 ... … Tactile switch, 36… Dovetail groove, 37… Top contact bar (contact body), 40…
… Drive shaft, 41 …… surrounding cam, 42 …… compression spring, 43 …… SELEX rotary (actuator).

Claims (3)

[Claims] 1. A mold release method for a plastic lens in which a plastic lens is molded between an upper mold and a lower mold, and after the molding, the upper mold and the lower mold are removed from the plastic lens. A mold releasing method for a plastic lens, wherein the upper mold and the lower mold are separated from the plastic lens by applying a mechanical compression force from the mold. 2. A mold releasing device for separating the upper mold and the lower mold from a plastic lens having an upper mold and a lower mold bonded to the front and back, and a pair of tables movably supported by a frame. An abutting body that is provided on each of the pair of tables and that does not come into radial contact with the upper die and the lower die but comes into radial contact with the plastic lens; An apparatus for releasing a plastic lens, comprising: an actuator for giving: a stopper means for restricting a maximum approaching position of the pair of tables. 3. The table according to claim 2, wherein one of the tables is an elevating table which is moved up and down by an actuator, and the other is a contacting / separating table which is brought into contact with and separated from the elevating table by another actuator. The pressing body is movably supported with respect to the contacting / separating table, and is provided with a switch means that is activated when the pressing body is pushed into the contacting / separating table. Mold release device for plastic lenses in which the actuator on the lifting table is turned on.