Abrading – Precision device or process - or with condition responsive... – With feeding of tool or work holder
Reexamination Certificate
2001-04-27
2003-04-15
Hail, III, Joseph J. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
With feeding of tool or work holder
C451S043000, C451S255000, C451S178000
Reexamination Certificate
active
06547642
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens periphery processing method and a lens periphery processing machine for processing an eyeglasses lens, based on lens frame shape data measured by contacting a contact element with a V shaped groove having V shape, formed in the inner face of a lens frame for eyeglasses lens, and the lens for eyeglasses made by those.
2. Description of the Prior Art
Generally, a lens frame which constitutes an eyeglasses frame, is formed with a V shaped groove formed in the inner face thereof, having a pair of inclined faces with its cross section having a V shape.
FIG. 9A
is a sectional view, in which a lens frame
1
of an eyeglasses frame (the whole part thereof is omitted) is cut in the direction perpendicular to the frame extending direction. A V shaped groove
1
d
which has inclined faces
1
b
and
1
c
composing a V shape, formed in an inner face
1
a
of a lens frame
1
, opens at a given opening angle &thgr;
1
from a bottom
1
e
of the V shaped groove toward the V shaped groove edges
1
f
and
1
g
. The opening angle &thgr;
1
and a depth H of the V shaped groove, differ slightly depending on the shape, material, manufacturer, and the like of the lens frame
1
.
Generally, the shape of the lens frame
1
is measured by contacting a contact element
2
(see
FIG. 8A
) provided on a frame shape measuring instrument etc., not shown, into contact with the V shaped groove
1
d.
The contact element
2
is provided with a tip end portion having an abacus bead shape, needle shape, spherical shape, rectangular shape, or the like (see Japanese Patent Application Laid-Open Nos. 51-119580, 58-196407, 58-38919, 60-52249, 62-88402, 63-24106, and 10-113853).
The contact element
2
shown in
FIG. 8A
has inclined faces
2
a
and
2
b
open at an angle &thgr;
2
and it is inserted in the V shaped groove
1
d
so that the points in the tip end portion thereof comes into contact with the V shaped groove edges
1
f
and
1
g
at the same time.
On the other hand, as shown in
FIG. 9B
, at the periphery of an eyeglasses lens
3
which is framed in the above described lens frame
1
, there is formed a V shaped portion
3
d
having a pair of inclined faces
3
b
and
3
c
inclined at an opening angle &thgr;
3
(almost the same angle as the above described angle &thgr;
2
) from a vertex
3
a
of the V shaped portion based on the lens frame shape data of the lens frame
1
measured with the above described contact element.
In this specification hereafter, the portion of eyeglass lens by which the eyeglass lens is correspondingly put into and held by above described V shaped groove, is referred to as the “V shaped portion” as above though actual cross section of the portion in accordance with this invention is rather not triangle.
On the sides of a lens front face
3
e
and lens rear face
3
f
of the V shaped portion
3
d
, a V shaped portion shoulder
3
i
ranging from the inclined face
3
b
of the V shaped portion
3
d
to a lens front edge
3
g
, and a V shaped portion shoulder
3
j
ranging from the inclined face
3
c
to a lens rear edge
3
h
, which have a width different according to the peripheral point of the eyeglasses lens
3
, are formed at the same time that the V shaped portion
3
d
is formed. The above described whole construction is referred to as a V shaped portion in this specification.
As shown in
FIG. 8B
, this V shaped portion is formed by using a grinding wheel
4
having the inclined faces
4
a
and
4
b
opening at an angle &thgr;
4
(almost the same angle as the above described angles &thgr;
2
and &thgr;
3
, for example, about 120 degrees).
On the eyeglasses lens
3
having been formed with the V shaped portion, the opening angle &thgr;
2
of the contact element
2
is approximately equal to the opening angle &thgr;
3
of the V shaped portion
3
d
. Therefore, as shown in
FIG. 8C
, the inclined faces
3
c
and
3
d
come into contact with the V shaped groove edges
1
f
and
1
g
in a state in which the a portion around vertex
3
a
of the V shaped portion
3
d
intrudes into the V shaped groove
1
d
, by which the eyeglasses lens
3
is framed in the lens frame
1
.
The above described prior art has problems as described below. The opening angle &thgr;
1
of the V shaped groove
1
d
formed in the lens frame
1
of eyeglasses frame, is not fixed and different according to eyeglasses frame, as described above.
On the other hand, the opening angle &thgr;
4
of the grinding wheel
4
for processing the V shaped portion of eyeglasses lens, has a predetermined angle, so that the opening angle &thgr;
3
of the V shaped portion
3
d
which is formed at the lens periphery of the eyeglasses lens
3
and processed with the grinding wheel
4
, is formed so as to be approximately equal to the opening angle &thgr;
4
of the grinding wheel
4
. Therefore, the V shaped portion
3
d
has a predetermined angle.
For this reason, when the eyeglasses lens
3
is framed in the V shaped groove
1
d
, because it has the V shaped portion
3
d
processed with the opening angle &thgr;
3
, the eyeglasses lens
3
can not be framed in a state in which the vertex
3
a
is in contact with the V shaped groove bottom
1
e
of the V shaped groove
1
d
. As shown in
FIG. 8C
, the V shaped groove edges l
f
and l
g
of the V shaped groove
1
d
in the lens frame
1
, come into contact with the inclined faces
3
b
and
3
c
of the V shaped portion
3
d.
However, the eyeglasses lens in this state is merely held only at the V shaped groove edges
1
f
and
1
g
of the eyeglasses frame, strong holding has not been expectable.
The reason for this is that since the opening angle &thgr;
3
of the V shaped portion
3
d
is formed so as to be approximately equal to the opening angle &thgr;
4
of the grinding wheel
4
(V shaped portion forming grinding wheel), the lens frame shape data is obtained by the contact element
2
having the opening angle &thgr;
2
which is approximately equal to the opening angle &thgr;
4
of the grinding wheel
4
(V shaped portion forming grinding wheel) in order to make the eyeglasses lens capable of being framed in any kind of the V shaped groove
1
d
of all eyeglass.
Because the eyeglasses frame is measured in this state on the lens frame itself, which is different from the V shape groove that the V shaped portion is actually held in. Even when the lens with the V shaped portion is processed based on this measurement, the lens periphery that can be strongly held in the eyeglasses frame, is not realized.
Also, it is preferable that the tip end width (thickness) w of the contact element
2
is made equal to or larger than a width W of the lens frame
1
of eyeglasses frame in order for the eyeglasses lens to be framed in the eyeglasses frame in which the opening angle &thgr;
1
and the depth H of the V shaped groove, are different variously.
However, for the reason of the construction of lens frame shape measuring instrument, the lens frame
1
must be fixed so as to withstand the measurement pressure of the contact element
2
, the tip end width (thickness) w of the contact element
2
could not be made equal to or larger than the width W of the lens frame
1
of eyeglasses frame because of prevention for the interference between a holding means for fixing the lens frame
1
and the tip end width (thickness) w of the contact element
2
.
SUMMARY OF THE INVENTION
Object of the Invention
The present invention has been made to solve the above problems, and accordingly an object thereof is to provide a lens periphery processing method, a lens periphery processing machine and lens for eyeglass, in which a V shaped portion that fits strongly in a lens frame of eyeglasses frame, can be processed in such a manner that V shaped portion contact with inside of the V shaped groove of the lens frame so that a contact element does not interfere with a holding means for fixing and holding a lens frame, and even if the V shaped groove is measured in a state when the lens frame is tilted, a difference in
Chapman and Cutler
Hail III Joseph J.
Kabushiki Kaisha TOPCON
Thomas David B.
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