JPH0611755Y2 - Lens chamfering jig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a chamfering jig for a lens, and in particular, is capable of effectively chamfering a lens having an uneven lens edge thickness.

[Prior Art] When the manufacturing process of a glass material spectacle lens is roughly divided into a roughing process, a sanding process, and a polishing process, the chamfering work is carried out particularly in the initial roughing process. The reason is that, when the lens is cut to a constant curvature surface in the rough-polishing step, the boundary surface between the lens surface side and the lens end surface side is sharp, fragile against external impact, and easily damaged. Chamfering is performed to grind and polish this sharp boundary surface. FIG. 4 shows a conventional example of such a chamfering process. A lens 2 is mounted and fixed on the rotary shaft 1 with the concave surface 2a side facing upward, and the rotary shaft 1 is rotated by a driving device such as a motor. Let
A hemispherical chamfer 3 having an inner surface provided with a diamond grindstone, a polishing pad, etc. is held by hand, the chamfer 3 is covered with the lens 2, and the chamfered portion 4 of the lens 2 is brought into contact with the inner surface of the chamfer 3. Then, the chamfering tool 3 is pressed against the lens 2 while pouring a lap mixture liquid such as abrasive grains, and the chamfering is performed while swinging in the front-rear, left-right direction. Also, the fifth
As shown in the figure, the rotating shaft 1 to which the rotation of the electric motor 10 is transmitted
It is also known that a lap tool 13 is attached to the upper end of 1, and the lens 2 is pressed against the lap plate 14 by hand with its chamfered portion facing down, and chamfering is performed while injecting the lap mixture liquid.

[Problems to be solved by the invention]

By the way, in the case of a spherical lens as a spectacle lens, since the radius of curvature on the concave side is constant and the lens edge thickness at the lens end is also constant, a chamfering jig such as the spherical chamfering tool 3 is used. The chamfering jig is replaced by the chamfering jig instead of the lap tool on a grinding machine equipped with a mechanism that allows chamfering with handrails or sliding of the lens for normal optical polishing and the lap tool. It is possible to process, but in the case of a lens having a compound curvature surface whose radius of curvature differs from the optical axis direction of the lens, such as an astigmatism lens or a progressive multifocal lens, the edge thickness of the lens end surface is different and the spherical chamfer When mechanically chamfering using the tool 3, a place with a high edge thickness is largely chamfered,
Chamfering Even unnecessary optical surfaces are chamfered, or chamfering of lenses with complex curvature surfaces, that is, lenses with complex curvature surfaces, such as chamfering processing with insufficient cutting or polishing is not performed where the edge thickness is low. Therefore, there is a demand for an efficient chamfering jig that can be chamfered uniformly regardless of the height of the edge and does not require manual work.

[Means for solving problems]

The lens chamfering jig according to the present invention has been made in order to meet the above-mentioned demands, and the supporting shaft portion fixed to the jig mounting portion of the swing shaft of the lens grinding machine and the lower and front and rear portions are opened. , And a jig portion attached to the support shaft portion with a space portion having a width larger than the outer diameter of the lens to be chamfered, and by stretching the jig portion between the lower ends of the jig portion, An elastic sheet covering the lower opening is provided, and a chamfering member attached to the lens side surface of the elastic sheet and pressed against the chamfered portion of the lens.

[Action]

In the present invention, when the chamfering member is pressed against the chamfered portion of the lens, the elastic sheet is curved upward, so that the chamfered member adheres to the chamfered portion regardless of the height of the lens edge,
To follow. Therefore, chamfering of a lens having a non-uniform lens edge thickness can be performed uniformly.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a perspective view showing an embodiment of a lens chamfering jig according to the present invention, and FIG. 2 is a perspective view before mounting an elastic sheet. In these figures, a lens chamfering jig generally designated by reference numeral 20 includes a stainless steel support shaft portion 21 formed in a cylindrical shape, and a stainless steel intermediate member 22 at the lower end of the support shaft portion 21. The jig portion 23 attached, the elastic sheet 24 stretched around the jig portion 23, the chamfering member 25 attached to the elastic sheet 24, and the like are generally configured.

The jig portion 23 has a space portion 29 that is opened downward and front and back by being formed in a downward U shape by three plates each made of stainless steel, that is, a central plate 26 and a pair of left and right side plates 27 and 28. Then, the central portion of the central plate 26 is screwed and fixed to the lower end of the support shaft portion 21 via the intermediate member 22. In this case, the intermediate member 22 is for reinforcement, and may be omitted if the central plate 26 itself has sufficient rigidity. The central plate 26 is formed into a rectangular shape having a length (width) of 10.9 cm, a width (length) of 3 cm, and a thickness of 0.5 cm.
7 and 28 are formed in a substantially square shape having a height of 3.2 cm, a width of 3 cm and a thickness of 0.5 cm, and the upper ends thereof are fixed to the end faces on the short side of the central plate 26 by set screws 30, respectively.

The elastic sheet 24 is made of rubber and has a length of 22 cm and a width of 3 c.
The pair of side plates 27,
By being stretched between the lower ends of 28, the space 29
Covers the lower opening of the. Both ends of the elastic sheet 24 are fixed to the outer surface of each of the side plates 27 and 28 by a plurality of bolts 31, nuts 32, washers 33 and the like. Therefore, a plurality of bolt insertion holes (not shown) are formed in each of the side plates 27 and 28, and a plurality of bolt insertion holes 34 are formed in the elastic sheet 24 as shown in FIG. There is.

The chamfering member 25 is composed of a polishing pad having a length of 3 cm, a width of 3 cm and a thickness of 3 mm, and two pads are bonded and fixed on the lower surface of the elastic sheet 24 from the side plates 27, 28 toward the center.

The width of the jig portion 23, in other words, the distance between the pair of side plates 27, 28 is larger than the outer diameter of the chamfered lens.

FIG. 3 is a perspective view of essential parts showing a state in which the lens chamfering jig 20 is attached to the lens grinder 40. A well-known Oscar type lens grinder is used as the lens grinder 40. The lens grinder 40 swings in the directions of arrows A and B by a well-known swing mechanism (not shown) including an eccentric cam plate and an eccentric arm. A swing shaft 41 that is moved and a lens mounting shaft 42 that is rotated at a constant speed (for example, 50 rpm) by a motor drive are provided, and a chuck 43 that holds the lens 2 is provided at the upper end of the lens mounting shaft 42. Installed. The lens 2 is a lens for which rough chamfering is completed, for example, a concave lens for astigmatism (outer diameter 6
5 mm ^phi, width 0.5mm chamfered surfaces, vertex power -1.00
Diopter, astigmatic power −3.00 diopter, edge thickness difference up to about 3.2 mm), and check 4 with the concave side up.
Set to 3.

A jig attachment portion 44 in the shape of a square rod is attached to the upper end of the swing shaft 41, and the lens chamfering jig 20 holds the support shaft portion 21 at the tip portion of the jig attachment portion 44. Attached to the chamfering member, that is, the polishing pad 25.
Is pressed against the chamfered portion 48 of the lens 2 (the peripheral edge of the lens 2 on the concave surface side) with an appropriate pressure (lap pressure). This lap pressure is given by the weight of the jig mounting portion 44.

Next, chamfering of the chamfered portion 48 by the lens chamfering jig 20 will be described.

First, the lens 2 is set in the chuck 43, and then the lens chamfering jig 20 is attached to the jig mounting portion 44 of the swing shaft 41.
After pressing the polishing pad 25 against the chamfered portion 48, the rotational speed of the lens mounting shaft 42, the number of swings of the swing shaft 41 (eg, 40 to 200 rpm), and the lap pressure (eg, 1 kg / c).
m ² ), polishing time (example 3 minutes), etc. are set. Next swing shaft 4
When 1 is swung in the directions of arrows A and B and the lens mounting shaft 42 is rotated, the lens 2 and the polishing pad 25 swing mutually, and the chamfered portion 48 is polished by the pad 25. At this time, the cerium oxide concentration is 30% by using a polishing liquid supply means (not shown) including a motor, a pump, a hose, etc.
The polishing liquid is supplied toward the concave surface of the lens 2.

In this polishing state, the polishing pad 25 is pressed against the chamfered portion 48 of the lens 2 with a lap pressure of about 1 kg, so that the elastic sheet 24 has a central portion in the space of the jig portion 23 as shown in FIG. It elastically deforms upward so as to enter the portion 29. Moreover, this deformation amount changes depending on the edge thickness of the lens, but since the polishing pad 25 is constantly pressed against the chamfered portion 48 by the pad pressure, the chamfered portion does not depend on the partial edge thickness of the lens 2. The chamfered portion 48 is polished by closely adhering to and following 48. Therefore, astigmatism lens,
It is suitable for chamfering a lens having a partially uneven lens edge such as a progressive lens.

Although the above-mentioned embodiment uses the jig portion 23 formed in a substantially U shape and opened downward and front and rear, the present invention is not limited to this and various modifications can be made. Of course, it may be a hemispherical shape, a conical shape, or the like. However, the jig portion 23 according to the present embodiment has an advantage that it has a simple shape and is easy to assemble.

Although the elastic sheet 24 made of rubber is used in the above embodiment, it may be made of plastic or metal. Further, instead of the polishing pad 25, if a grindstone piece for sanding or rough grinding, sandpaper or the like is used as the chamfering member, not only polishing but also chamfering processing suitable for the purpose can be performed, for example. is there.

Further, although the present embodiment has described the case where the chamfering jig 20 is set in the Oscar type lens grinder, the lens mounting shaft 42 on which the lens 2 is fixed and rotated, and the chamfering jig 20 are pressed onto the lens 2. Swing shaft 41 to swing
Any lens grinding machine equipped with and can be used.

[Effect of device]

As described above, according to the chamfering jig according to the present invention, the chamfering member is attached to the elastic sheet stretched around the jig portion, and the chamfering member is pressed against the lens so that the chamfering portion is separated into the jig and the lens. Since it is configured to polish by mutual sliding of, the chamfering member has excellent followability with respect to the chamfered portion,
Even a lens having a non-uniform lens edge can be uniformly polished at its chamfered portion, which is suitable for application to an astigmatic lens, a progressive lens, or the like. In addition, since the chamfered portion can be automatically polished by setting it in the lens grinder, no skill is required and polishing can be performed in a short time, which is also of great economic value.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a lens chamfering jig according to the present invention, and FIG. 2 is a perspective view before mounting an elastic sheet,
FIG. 3 is a perspective view showing a lens chamfering jig set in a lens grinder, and FIGS. 4 and 5 are views showing a conventional chamfering method. 2 ... Lens, 20 ... Lens chamfering jig, 21 ...
… Spindle part, 23 …… Jig part, 24 …… Elastic sheet, 25
...... Chamfering member, 29 …… Space part, 40 …… Lens grinder, 41 …… Swing shaft, 42 …… Lens mounting shaft, 43 ……
Check, 44 ... Jig attachment part, 48 ... Chamfer part.

Claims (1)

[Scope of utility model registration request] 1. A support shaft portion fixed to a jig mounting portion of a swing shaft of a lens grinding machine, and a space portion opened downward and front and rear and having a width larger than an outer diameter of a lens to be chamfered. Attached to the supporting shaft portion, an elastic sheet that covers the lower opening of the space portion by being stretched between the lower ends of the jig portion, and a lens side surface of the elastic sheet. A chamfering member that is mounted and is pressed against the chamfered portion of the lens.