JPH0547380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molding thickness setting device for molding a plastic lens.

[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 a retaining tape around the entire circumference so as to span the peripheral surfaces of the pair of molds. The pair of molds is held by adhesively winding the mold, and a plastic raw material liquid to be polymerized and hardened is injected into the space formed between the two molds to form a lens.

When arranging the pair of molds facing each other and holding them in the correct position, first, the opposing molding surfaces of the pair of molds are brought into contact with the reference point or reference edge of the gauge from both sides, so that they are parallel to each other. In this state, use a centering jig to center the molds and hold the circumferential surfaces of both molds, and then use the holding means to hold the molds on the back side of each of the pair of molds.
For example, the gauge is suctioned and held using vacuum pressure, and then the gauge is removed and a holding tape is wound.

[Problem to be solved by the invention]

According to the conventional apparatus equipped with the gauge and holding means as described above, the thickness and thickness accuracy of the molded lens are determined by the gauge.

Therefore, in order to mold lenses of various thicknesses with a predetermined thickness accuracy, it is necessary to prepare as many gauges as there are types, and to keep the thickness accuracy of all of them within a predetermined range. Must be. This results in increased manufacturing costs and complicated storage. Furthermore, if the gauges in stock do not have a predetermined size, a new gauge must be made, resulting in poor compatibility.

The purpose of the present invention is to solve this problem and provide a molding thickness setting device for plastic lens molding, which can accurately mold lenses of any thickness just by preparing one gauge. It is said that

[Means to solve the problem]

According to the invention, the above object relates to a method thereof;
In the molding thickness setting device for molding a plastic lens between a pair of disc-shaped molds that are placed opposite each other at a predetermined interval, the opposing molding surfaces of the pair of molds are in contact with each other and are positioned parallel to each other. A gauge having a point or a reference edge, a holding means for sucking and holding a pair of molds that are brought into contact with the reference point or reference edge of the gauge on their back surfaces, and a pair of molds that are sucked and held by the holding means. a driving means for moving the holding means so as to separate the pair of molds from each other and return them to the starting position, starting from a position where they can come into contact with the reference point or reference edge of the gauge, and supporting the driving means and driving the holding means; This is achieved by comprising a position setting means for setting the means at an arbitrary position in the moving direction of the holding means.

[Effect]

Based on the apparatus of the present invention as described above, the molding thickness for molding a plastic lens is set in the following manner.

First, a gauge is prepared, and the opposed forming surfaces of a pair of molds are brought into contact with the reference points or reference edges on both sides of the gauge in a centered state, and this position is maintained. In this state, the two opposing molding surfaces are at their normal positions.

Next, the pair of molds are held by suction on their back surfaces by the holding means. The position where the pair of molds held by suction abut against the reference point or reference edge of the gauge becomes the starting point of the holding means.

Next, the holding means is moved by the driving means, the pair of molds are separated from each other, and the gauge is removed. After that, the mold returns to the starting position.

Further, the driving means is moved by a set amount by the position setting means, and the holding means is moved by the set amount from the starting point. As a result, the distance between the pair of molds that was originally set by the gauge changes by the set amount. This setting amount is determined by the difference between the above-mentioned interval and the desired lens thickness after molding.

In this state, a tape is adhesively wound around the pair of molds so as to span the circumferential surfaces of the molds, thereby forming an injection space for the plastic raw material liquid.

〔Example〕

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

FIG. 1 is a schematic diagram showing an apparatus according to an embodiment of the present invention.

In FIG. 1, 1 is a guide rod fixed to the device frame. Two movable blocks 2 and 3 are slidably guided on the guide rod 1. Holding means 4 and 5 having the same structure are fixed to the two movable blocks 2 and 3, respectively, facing each other.

The holding means 4, 5 have recesses 4B, 5B for suction at the tips of pipe parts 4A, 5A connected to a vacuum device (not shown), and O-rings 4C are attached to the peripheries of the recesses 4B, 5B. , 5C are provided. The holding means 4 and 5 are respectively fixed to the movable blocks 2 and 3 by tube portions 4A and 5A so that the recesses 4B and 5B face each other. Note that the opposing position can be freely adjusted using screws 2A and 3A. Further, the holding means 4 and 5 are rotatable together by the same means (not shown).

A gauge 6 and a centering device 7 are arranged between the holding means 4 and 5. The gauge 6 is a plate-shaped body with an angular cross section, and has an annular shape with a gauge thickness T. The gauge 6 contacts the curved surface of the mold M with its respective protrusions 6A and 6B at the upper and lower inner edges, and the mold is heated. It is designed to show the reference position. On the other hand, the centering device 7 approaches from the left and right and comes into contact with the circumferential surface of the mold M to center the mold M on the gauge 6. These gauges and centering devices may be of known type.

Note that the gauge 6 requires only the parallelism of the upper and lower surfaces (surfaces including the inner edge), and the thickness T of the gauge does not require accuracy. However, the thickness T of the gauge must be accurately measured.

The movable block 2 is attached to a rod 8A of a cylinder 8 serving as a driving means in an immovable position, and is capable of reciprocating by a set distance l1. A rod 9A of a cylinder 9 as a driving means is also attached to the other movable block 3. A small cylinder 11 is attached to the cylinder 9 via a metal fitting 10.
The chuck portion 1 provided on the rod 11A of 1
The rod 9A can be fixed at any position by actuating the rod 1B, and the reference position of the mold corresponding to the thickness T of the gauge can be set.

The support plate 12 supporting the cylinder 9 is
It is attached to the rod 13A of the other cylinder 13. Although the cylinder 13 is fixed, the set distance l3, which is the stroke of the rod 13A, is
It is adapted to be adjusted by a stopper 14 which can be set to any position. Therefore, the movable block 3 driven by the rod 9A of the cylinder 9 attached to the support plate 12 as described above can be moved by l3 from the position where the rod 9A is fixed by the chuck portion 11B. . Thus,
The support plate 12, cylinder 13, and stopper 14 constitute position setting means for the cylinder 9 as the drive means.

Next, a procedure for setting the molding thickness using the apparatus of this embodiment having such a configuration will be explained.

First, a predetermined pair of molds M are prepared and placed in contact with the gauge 6 from above and below. At that time, the lower mold is attached to the O-ring 4 of the holding means 4.
It is supported on C.

Next, the centering device 7 is brought into contact with the peripheral surfaces of the upper and lower molds M from the left and right, respectively, to center these molds. At this stage, the pair of molds M are in contact with the O-rings 4C, 5C of the pair of holding means 4, 5 at their back surfaces.

In this state, the vacuum pressure of the vacuum device is applied to the recess 4 through the pipe portions 4A and 5A of the holding means 4 and 5.
B, 5B are applied to hold the pair of molds M by vacuum pressure. Therefore, the pair of molds M are held at a position where the distance between their opposing molding surfaces corresponds to the thickness T of the gauge. In this state, the small cylinder 11 is operated to move the rod 9A of the cylinder 9, which serves as a driving means for driving the holding means 5, into the cylinder 9.
Fixed against.

Thereafter, by operating the cylinder 8, the movable block 2 is lowered by a set distance l1, and the distance between the molding opposing surfaces of the pair of molds M, which are held by the holding means 4 and 5 by suction, is widened. Remove gauge 6.

Thereafter, the cylinder 8 is operated again to raise the mold M back to its original position and fixed, and the cylinder 13 is operated to bring the support plate 12 into contact with the stopper 14. As a result, the upper movable block 3 is lowered by l3, and the distance between the opposing molding surfaces of the pair of molds M is T-
It becomes l3.

Finally, by slowly rotating the holding means 4 and 5 together, the tape is adhesively wound around the circumferential surfaces of the pair of molds M, in preparation for molding the plastic lens. . Thus, by setting l3 to any positive or negative position, the thickness of the plastic lens can be accurately set to a desired value.

The present invention is not limited to this embodiment, and various modifications are possible. For example, a space for removing the gauge 6 can be provided by reciprocating the cylinder 9 by a set distance l2 at an arbitrary position without using the cylinder 8. Furthermore, in any case, if the gauge 6 can be separated radially outward, the stroke of the cylinder can be small.

Furthermore, the cylinder 1 as the position setting means
3 can also be implemented by a motor with a rotation/linear motion conversion mechanism or a solenoid mechanism.

[Effects of the Invention] As described above, the present invention makes it possible to move the relative position of the holding means for holding a pair of molds by an arbitrary set distance from the initial holding position. Lenses can be molded without the inconvenience of using gauges with a variety of gauge thicknesses as in the past, resulting in greater economic benefits.
Moreover, the distance between the facing surfaces of the pair of molds, which corresponds to the thickness of the gauge, is continuously variable. This eliminates the need for additional machining of gauges. Furthermore, it is sufficient to manufacture the above-mentioned gauge with only the parallelism of the top and bottom surfaces accurate, and the thickness of the gauge only needs to be accurately measured.In addition to making the gauge easy to process, the accuracy is It becomes the same during molding, making it easier to control quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus according to an embodiment of the present invention. 4, 5... Holding means, 6... Gauge, 8, 9...
...Driving means (cylinder), 12, 13, 14...
Position setting means (12... support plate, 13... cylinder, 14... stopper, M... mold.

Claims (1)

[Scope of Claims] 1. In the molding thickness setting device for molding a plastic lens between a pair of disc-shaped molds that are placed opposite each other with a predetermined interval, the opposing molding surfaces of the pair of molds are in contact with each other. a gauge having a reference point or a reference edge for positioning these in parallel; a holding means for holding a pair of molds by suction on their back surfaces, which are brought into contact with the reference point or reference edge of the gauge; driving means for moving the holding means so as to separate the pair of molds from each other and return them to the starting position, starting from a position where the pair of molds are brought into contact with a reference point or a reference edge of the gauge; A mold thickness setting device for molding a plastic lens, comprising: position setting means for supporting a driving means and setting the driving means at an arbitrary position in the moving direction of the holding means.