Abrading – Precision device or process - or with condition responsive... – With feeding of tool or work holder
Reexamination Certificate
1999-10-04
2001-12-11
Rachuba, M. (Department: 3724)
Abrading
Precision device or process - or with condition responsive...
With feeding of tool or work holder
C451S041000, C451S042000, C451S043000, C451S044000
Reexamination Certificate
active
06328630
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to an eyeglass end face machining method, particularly to the polishing to a mirror polishing that is performed on the end face after bevel edging, or the planing, such as machining to a mirror polishing, that is performed on the end face after edging.
2. Description of the Related Art
The lens end face of rimless eyeglasses lenses usually referred to as three-piece eyeglass lenses is exposed and not covered by a rim, etc., and therefore, they must have a surface that has been polished until glossy. In response to this need, technology has been presented whereby eyeglass lenses, whose end face has thus far been smoothed manually in order to obtain a face that has been polished until glossy, are mechanically polished by placing a movement mechanism with tracing capability in the polishing wheel part (for instance, Japanese Patent Laid-Open No. Sho 64-87144). This grinds inclined faces, such as the end face of polyhedron cut lenses, etc., and although the shape around the eyeglass lens is complex because of the polyhedron cut, the end face itself, which becomes the surface to be grounded, is a flat surface and simple. Consequently, the above-mentioned technology cannot be used when the surface to be polished itself has a complex shape, such as lens end faces with a bevel. Now, because the lens end face with a bevel is usually concealed by the rim of the frame and there is no need to polish the bevel faces, a lens end face with a bevel itself is usually not polished.
However, there has been a demand in recent years for thin rims in order to obtain frames that are more lightweight and fashionable, etc., and it is often the case that if the lens fitted into the rim is a strong-minus-power lens with a thick edge, the lens will protrude from the rim of the frame. It is pointed out that the bevel faces remains white when polishing of the lens end face is completed by bevel-polishing and this poses a problem aesthetically. Polishing the bevel surface that remains white until it is transparent is only accomplished by buff polishing the bevel surface by hand, etc., and this takes time and increases cost.
The objective of the present invention is to solve the above-mentioned problems with prior art by mechanically polishing the bevel faces in 2 steps and to present a lens end face machining method, wheel and device for eyeglass lens end face machining with which it is possible to speed up the polishing process and make finishing precision uniform and obtain fashionable eyeglass.
Moreover, in addition to the aesthetic problem of the lens end face remaining white after bevel polishing that was previously described, there is a problem with polishing precision and fashionable eyeglasses in that when planing, such as smooth machining and machining to a mirror polishing etc., is performed with a wheel that has a bevel-groove and a planing face, streaks are made. That is, cylindrical grinding stone called diamond wheels(stone) have a bevel-groove for formation of a bevel at the end face of the eyeglass lens and a flat face for flat machining the end face of an eyeglass lens. In further detail, the wheel has groove inclined face
301
for V finishing having a specific angle with respect to the axial direction called angle No. 1, flank
203
for the eyebrow of the frames continuous with this groove inclined face
301
having a specific angle with respect to the axial direction referred to as angle No. 2 that is smaller than angle No. 1, and flat finishing face
303
continuous with this flank
302
for flat machining and parallel to the axial direction on the surface around the periphery of the wheel. The inclination at boundary K between above-mentioned flank
302
and flat finishing face
303
is not continuous.
Consequently, when an eyeglass lens moves past boundary K to the left in the direction of the X axis during flat machining, apex A of the end face of eyeglass lens
6
straddles boundary K and a streak from boundary K is made in end face
6
a
of eyeglass lens
6
. When a streak is made in end face
6
a
of the eyeglass lens, edging precision drops and becomes non-uniform, and the product is not fashionable. Therefore, such a streak is undesirable. This is particularly a problem with flat finished surfaces that remain white and are further given a mirror finish so that they are transparent.
Thereupon, in order to solve this problem, flat finishing face
303
is made longer in the axial direction so that even if eyeglass lens
6
moves to the left in the direction of the X axis during flat edging, it will not pass boundary K. However, there is a problem in that as a result, wheel
1
is larger.
Inerdentally there is a demand for mechanical polishing of the bevel face that remains white using a wheel as a means of solving the above-mentioned aesthetic problem of the lens end face remaining white after bevel polishing because buffing, etc., manually takes time and increases cost. However, there is also a problem when a polishing wheel is used with the existing wheel in that the device becomes bigger.
The objective of the present invention is to solve the above-mentioned problems of prior art and present an eyeglass lens end face matching method with which polishing precision is uniform, the product is excellent in terms of being fashionable, and the device can be reduced in size. Another objective of the present invention is to present an eyeglass end face machining method with which it is possible to add a polishing wheel that can give the eyeglass lens end face a mirror polish without greatly increasing length of the wheel in the axial direction.
SUMMARY OF THE INVENTION
The first invention is an eyeglass lens end face machining method, comprising the steps of polishing one inclined face of the bevel formed in the end face of an eyeglass lens using a wheel for bevel polishing with inclined faces that essentially match the inclined faces of above-mentioned bevel and polishing the other inclined face of above-mentioned bevel that remains by this polishing.
The fact that the wheel for bevel polishing has an inclined face that essentially corresponds to the inclined face in the bevel formed in the end face of the eyeglass lens is not limited to the case where the two inclined faces of the bevel are continuous at the apex of the bevel and also includes the case where the two inclined faces have a space in between. Moreover, the inclined face corresponding to the inclined face of the bevel is not limited to only the inclined face of the bevel and also includes a flat area that is continuous with the bevel. Consequently, there are cases where there is a flat part continuous with the notch at one inclined face and the other inclined face of the bevel.
The inclined face of the bevel is not transparent and remains white when the end face of the eyeglass lens has been bevel-polished. Therefore, the inclined face of the bevel is ground with a wheel having inclined faces corresponding to the bevel by a first and a second process. By means of the first process, one inclined face of the wheel is pressed against one inclined face of the bevel and one inclined face of the bevel is polished. By means of the second process, the other inclined face of the bevel and polishing irregularities that remain after the first process are polished using the other inclined face of the wheel. In this case, polishing is performed so that the apex of the bevel after polishing returns to the same position as before polishing. When both inclined faces of the bevel are polished in this way, the inclined faces of the bevel that remained white are given a mirror polish and are transparent. Consequently, even if the bevel face of the eyeglass lens protrudes from the thin film of a metal frame, or even if the bottom half of the eyeglass lens is completely exposed, as with rimlon type frames, aesthetics can be maintained. Moreover, the bevel face is given a mirror finish mechanically using a wheel and therefore, polishing can be completed in a s
Daimaru Takashi
Jinbo Masahiro
Hoya Corporation
Oliff & Berridg,e PLC
Rachuba M.
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