U.S. patent application number 10/186978 was filed with the patent office on 2003-01-09 for grinding water tank unit for use in processing eyeglass lens, device for separating processing debris, and eyeglass lens processing apparatus having the tank unit or device.
This patent application is currently assigned to NIDEK CO., LTD.. Invention is credited to Mizuno, Toshiaki.
Application Number | 20030008603 10/186978 |
Document ID | / |
Family ID | 27347079 |
Filed Date | 2003-01-09 |
United States Patent
Application |
20030008603 |
Kind Code |
A1 |
Mizuno, Toshiaki |
January 9, 2003 |
Grinding water tank unit for use in processing eyeglass lens,
device for separating processing debris, and eyeglass lens
processing apparatus having the tank unit or device
Abstract
A grinding water tank unit which enables reuse of grinding water
that has been used for processing an eyeglass lens, includes: a
tank in which the grinding water is stored; a filter, disposed in
the tank, for filtering the grinding water to be separate from
processing debris, the filter having a sealed hollow portion; a
first water suction pump; and a first water suction passage which
connects the hollow portion to the first pump, and through which
the grinding water filtered by the filter is sucked by suction of
the first pump.
Inventors: |
Mizuno, Toshiaki; (Aichi,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
WASHINGTON
DC
20037
US
|
Assignee: |
NIDEK CO., LTD.
|
Family ID: |
27347079 |
Appl. No.: |
10/186978 |
Filed: |
July 2, 2002 |
Current U.S.
Class: |
451/64 ;
451/442 |
Current CPC
Class: |
B24B 57/02 20130101;
B24B 9/146 20130101 |
Class at
Publication: |
451/64 ;
451/442 |
International
Class: |
B24B 007/00; B24B
009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 3, 2001 |
JP |
P2001-202808 |
Jul 31, 2001 |
JP |
P2001-232203 |
Jul 31, 2001 |
JP |
P2001-232204 |
Claims
What is claimed is:
1. A grinding water tank unit which enables reuse of grinding water
that has been used for processing an eyeglass lens, comprising: a
tank in which the grinding water is stored; a filter, disposed in
the tank, for filtering the grinding water to be separate from
processing debris, the filter having a sealed hollow portion; a
first water suction pump; and a first water suction passage which
connects the hollow portion to the first pump, and through which
the grinding water filtered by the filter is sucked by suction of
the first pump.
2. The tank unit according to claim 1, wherein the filter includes
a substantially plate-like filter which is disposed at a bottom of
the tank, and which has a filter surface substantially equal in
area to an interior bottom surface of the tank.
3. The tank unit according to claim 2, wherein the filter has the
hollow portion defined between the filter and the interior bottom
surface of the tank.
4. The tank unit according to claim 1, further comprising: a first
water supply passage which connects the first pump to the tank, and
through which the grinding water sucked by the first pump is
supplied to the tank.
5. The tank unit according to claim 1, further comprising: an
antifoaming device for eliminating bubbles developing in the
tank.
6. The tank unit according to claim 5, wherein the antifoaming
device has a water ejection opening disposed at a predetermined
height in the tank, and eliminates the bubbles using water pressure
of water ejected from the water ejection opening.
7. The tank unit according to claim 6, further comprising: a second
water suction pump; a second water suction passage which connects
the tank to the second pump, and through which the grinding water
in the tank is sucked by suction of the second pump; and a second
water supply passage which connects the second pump to the water
ejection opening, and through which the grinding water sucked by
the second pump is supplied to the water ejection opening.
8. The tank unit according to claim 6, wherein an ejection
direction of the water ejection opening is changeable.
9. An eyeglass lens processing apparatus for processing an eyeglass
lens, comprising: a processing chamber in which a lens grinding
tool is disposed; a tank in which grinding water is stored; a drain
passage through which the grinding water is drained from the
processing chamber to the tank; a filter, disposed in the tank, for
filtering the grinding water to be separate from processing debris,
the filter having a sealed hollow portion; a water suction pump;
and a water suction passage which connects the hollow portion to
the pump, and through which the grinding water filtered by the
filter is sucked by suction of the pump.
10. The eyeglass lens processing apparatus according to claim 9,
further comprising: a water supply unit for supplying the grinding
water stored in the tank to the processing chamber.
11. The eyeglass lens processing apparatus according to claim 10,
further comprising: a water supply passage which connects the pump
to the tank, and through which the grinding water sucked by the
pump is supplied to the tank.
12. A processing debris separating device for separating grinding
water, used for processing an eyeglass lens and drained to a tank,
from processing debris, comprising: a filter, disposed in the tank,
for filtering the grinding water to be separate from the processing
debris, the filter having a sealed hollow portion; a water suction
pump; and a water suction passage which connects the hollow portion
to the pump, and through which the grinding water filtered by the
filter is sucked by suction of the pump.
13. A grinding water tank unit which enables reuse of grinding
water that has been used for processing an eyeglass lens,
comprising: a first tank in which the grinding water is stored; a
filter for filtering the grinding water to be separate from
processing debris, the filter having a chamber in which the
processing debris is accumulated; a pressurizing pump; a water
suction passage which connects the first tank to the pump, and
through which the grinding water in the first tank is sucked by
suction of the pump; and a first water supply passage which
connects the pump to the chamber of the filter, and through which
the grinding water sucked by the pump is supplied to the chamber
under a predetermined water pressure.
14. The tank unit according to claim 13, wherein the filter is
disposed in the first tank.
15. The tank unit according to claim 13, wherein the filter is
disposed in a second tank provided outside the first tank.
16. The tank unit according to claim 15, further comprising: a
second water supply passage which connects the second tank to the
first tank.
17. The tank unit according to claim 15, further comprising: an
anti-foaming device for eliminating bubbles developing in the first
tank.
18. An eyeglass lens processing apparatus for processing an
eyeglass lens, comprising: a processing chamber in which a lens
grinding tool is disposed; a tank in which grinding water is
stored; a drain passage through which the grinding water is drained
from the processing chamber to the tank; a filter for filtering the
grinding water to be separate from processing debris, the filter
having a chamber in which the processing debris is accumulated; a
pressurizing pump; a water suction passage which connects the tank
to the pump, and through which the grinding water in the tank is
sucked by suction of the pump; and a water supply passage which
connects the pump to the chamber of the filter, and through which
the grinding water sucked by is the pump is supplied to the chamber
under a predetermined water pressure.
19. The eyeglass lens processing apparatus according to claim 18,
further comprising: a water supply unit for supplying the grinding
water stored in the tank, to the processing chamber.
20. A processing debris separating device for separating grinding
water, used for processing an eyeglass lens and drained to a tank,
from processing debris, comprising: a filter for filtering the
grinding water to be separate from the processing debris, the
filter having a chamber in which the processing debris is
accumulated; a pressurizing pump; a water suction passage which
connects the tank to the pump, and through which the grinding water
in the tank is sucked by suction of the pump; and a water supply
passage which connects the pump to the chamber of the filter, and
through which the grinding water sucked by the pump is supplied to
the chamber under a predetermined water pressure.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to an eyeglass lens processing
apparatus for processing eyeglass lenses; to a grinding water tank
unit for storing and circulating grinding water; and to a
processing debris separator for separating grinding water from
processing debris.
[0003] 2. Description of the Related Art
[0004] Grinding water is fed to an eyeglass lens processing
apparatus in order to cool a portion of a lens to be processed and
remove debris produced during the course of processing the lens. A
water-supply method employed in this connection may be classified
into a waterline direct coupling method for supplying water from a
waterline directly to a processing apparatus main unit; and a
circulation method. According to the circulation method, grinding
water stored in a tank is pumped up and fed to the processing
apparatus main unit using a pump. Grinding water having been used
is drained into the tank, and the grinding water is then
reused.
[0005] The waterline direct coupling method presents a problem of
processing debris being drained directly into sewage from the
processing apparatus main unit together with used grinding water.
Even the circulation method suffers a problem of difficulty in
completely separating processing debris from grinding water,
thereby requiring effort in removing solely processing debris.
Another problem of the circulation method lies in that a portion of
processing debris is drained into a sewage along with the grinding
water stored in the tank at the time of replacement of grinding
water.
[0006] When a plastic lens is processed, bubbles develop in drained
grinding water. Particularly, when the eyeglass processing
apparatus of circulation type performs processing operation over a
period of time, the tank is filled with bubbles, sometimes
resulting in leakage of bubbles from the tank or overflow of
bubbles to a processing chamber of the processing apparatus main
unit. For this reason, replacement of grinding water and cleaning
of inside of the tank must be performed at frequent intervals.
SUMMARY OF THE INVENTION
[0007] In light of the drawback in the related art, an object of
the invention is to provide an apparatus capable of readily
separating grinding water in a tank from processing debris.
[0008] Another object of the invention is to provide an apparatus
capable of diminishing the amount of bubbles developing in a
tank.
[0009] To solve the drawback, the invention is characterized by the
following arrangements.
[0010] (1) A grinding water tank unit which enables reuse of
grinding water that has been used for processing an eyeglass lens,
comprising:
[0011] a tank in which the grinding water is stored;
[0012] a filter, disposed in the tank, for filtering the grinding
water to be separate from processing debris, the filter having a
sealed hollow portion;
[0013] a first water suction pump; and
[0014] a first water suction passage which connects the hollow
portion to the first pump, and through which the grinding water
filtered by the filter is sucked by suction of the first pump.
[0015] (2) The tank unit according to (1), wherein the filter
includes a substantially plate-like filter which is disposed at a
bottom of the tank, and which has a filter surface substantially
equal in area to an interior bottom surface of the tank.
[0016] (3) The tank unit according to (2), wherein the filter has
the hollow portion defined between the filter and the interior
bottom surface of the tank.
[0017] (4) The tank unit according to (1), further comprising:
[0018] a first water supply passage which connects the first pump
to the tank, and through which the grinding water sucked by the
first pump is supplied to the tank.
[0019] (5) The tank unit according to (1), further comprising:
[0020] an antifoaming device for eliminating bubbles developing in
the tank.
[0021] (6) The tank unit according to (5), wherein the antifoaming
device has a water ejection opening disposed at a predetermined
height in the tank, and eliminates the bubbles using water pressure
of water ejected from the water ejection opening.
[0022] (7) The tank unit according to (6), further comprising:
[0023] a second water suction pump;
[0024] a second water suction passage which connects the tank to
the second pump, and through which the grinding water in the tank
is sucked by suction of the second pump; and
[0025] a second water supply passage which connects the second pump
to the water ejection opening, and through which the grinding water
sucked by the second pump is supplied to the water ejection
opening.
[0026] (8) The tank unit according to (6), wherein an ejection
direction of the water ejection opening is changeable.
[0027] (9) An eyeglass lens processing apparatus for processing an
eyeglass lens, comprising:
[0028] a processing chamber in which a lens grinding tool is
disposed;
[0029] a tank in which grinding water is stored;
[0030] a drain passage through which the grinding water is drained
from the processing chamber to the tank;
[0031] a filter, disposed in the tank, for filtering the grinding
water to be separate from processing debris, the filter having a
sealed hollow portion;
[0032] a water suction pump; and
[0033] a water suction passage which connects the hollow portion to
the pump, and through which the grinding water filtered by the
filter is sucked by suction of the pump.
[0034] (10) The eyeglass lens processing apparatus according to
(9), further comprising:
[0035] a water supply unit for supplying the grinding water stored
in the tank to the processing chamber.
[0036] (11) The eyeglass lens processing apparatus according to
(10), further comprising:
[0037] a water supply passage which connects the pump to the tank,
and through which the grinding water sucked by the pump is supplied
to the tank.
[0038] (12) A processing debris separating device for separating
grinding water, used for processing an eyeglass lens and drained to
a tank, from processing debris, comprising:
[0039] a filter, disposed in the tank, for filtering the grinding
water to be separate from the processing debris, the filter having
a sealed hollow portion;
[0040] a water suction pump; and
[0041] a water suction passage which connects the hollow portion to
the pump, and through which the grinding water filtered by the
filter is sucked by suction of the pump.
[0042] (13) A grinding water tank unit which enables reuse of
grinding water that has been used for processing an eyeglass lens,
comprising:
[0043] a first tank in which the grinding water is stored;
[0044] a filter for filtering the grinding water to be separate
from processing debris, the filter having a chamber in which the
processing debris is accumulated;
[0045] a pressurizing pump;
[0046] a water suction passage which connects the first tank to the
pump, and through which the grinding water in the first tank is
sucked by suction of the pump; and
[0047] a first water supply passage which connects the pump to the
chamber of the filter, and through which the grinding water sucked
by the pump is supplied to the chamber under a predetermined water
pressure.
[0048] (14) The tank unit according to (13), wherein the filter is
disposed in the first tank.
[0049] (15) The tank unit according to (13), wherein the filter is
disposed in a second tank provided outside the first tank.
[0050] (16) The tank unit according to (15), further
comprising:
[0051] a second water supply passage which connects the second tank
to the first tank.
[0052] (17) The tank unit according to (15), further
comprising:
[0053] an anti-foaming device for eliminating bubbles developing in
the first tank.
[0054] (18) An eyeglass lens processing apparatus for processing an
eyeglass lens, comprising:
[0055] a processing chamber in which a lens grinding tool is
disposed;
[0056] a tank in which grinding water is stored;
[0057] a drain passage through which the grinding water is drained
from the processing chamber to the tank;
[0058] a filter for filtering the grinding water to be separate
from processing debris, the filter having a chamber in which the
processing debris is accumulated;
[0059] a pressurizing pump;
[0060] a water suction passage which connects the tank to the pump,
and through which the grinding water in the tank is sucked by
suction of the pump; and
[0061] a water supply passage which connects the pump to the
chamber of the filter, and through which the grinding water sucked
by the pump is supplied to the chamber under a predetermined water
pressure.
[0062] (19) The eyeglass lens processing apparatus according to
(18), further comprising:
[0063] a water supply unit for supplying the grinding water stored
in the tank, to the processing chamber.
[0064] (20) A processing debris separating device for separating
grinding water, used for processing an eyeglass lens and drained to
a tank, from processing debris, comprising:
[0065] a filter for filtering the grinding water to be separate
from the processing debris, the filter having a chamber in which
the processing debris is accumulated;
[0066] a pressurizing pump;
[0067] a water suction passage which connects the tank to the pump,
and through which the grinding water in the tank is sucked by
suction of the pump; and a water supply passage which connects the
pump to the chamber of the filter, and through which the grinding
water sucked by the pump is supplied to the chamber under a
predetermined water pressure.
[0068] The present disclosure relates to the subject matter
contained in Japanese patent application Nos. 2001-202808 (filed on
Jul. 3, 2001), 2001-232203 (filed on Jul. 31, 2002) and 2001-232204
(filed on Jul. 31, 2002), which are expressly incorporated herein
by reference in their entireties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0069] FIG. 1 is an overall schematic diagram of an eyeglass lens
processing apparatus according to a first embodiment;
[0070] FIG. 2 is a schematic diagram of an antifoaming device;
[0071] FIG. 3 is a view of a filter of the apparatus of the first
embodiment when viewed from a bottom surface of a tank;
[0072] FIG. 4A is a view showing a first modification of the
antifoaming device;
[0073] FIG. 4B is a view showing a second modification of the
antifoaming device;
[0074] FIG. 5 is a view showing an example in which a processing
debris separator is constructed as a discrete device;
[0075] FIG. 6 is an overall schematic diagram showing an eyeglass
lens processing apparatus according to a second embodiment;
[0076] FIG. 7A is a view showing a first modification of filter
layout of the apparatus of the second embodiment; and
[0077] FIG. 7B is a view showing a second modification of filter
layout of the apparatus of the second embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0078] <First Embodiment>
[0079] An embodiment of the invention will now be described by
reference to the drawings. FIG. 1 is an overall schematic diagram
of an eyeglass lens processing apparatus according to a first
embodiment of the invention. The processing apparatus is roughly
constituted of a processing apparatus main unit 1; a table 100 on
which the main unit 1 is to be placed; and a circulation-type
grinding water tank unit 200 to be placed in the table.
[0080] Disposed in the housing of the main unit 1 is a processing
section 10 comprising two lens rotary shafts (e.g., chuck shafts)
2R, 2L for holding a lens LE to be processed; a carriage section 3
to which the lens rotary shafts 2R, 2L are rotatably attached; and
a grinder 5 attached to a rotary shaft 6 for processing the edge of
the lens LE. The grinder 5 is constituted of three grinding stones:
namely, a rough grinding stone for plastics; a rough grinding stone
for glass; and a finishing grinding stone having a groove for
beveling and a flat processing surface. The grinder 5 is rotated by
an unillustrated motor. The carriage section 3 is movable in the
axial direction of the lens rotary shafts 2R, 2L, and also movable
relative to the grinder 5. For more details of the processing
section 10, please refer to Reference No. 35,898 (Japanese Patent
Application Laid-Open No. 212661/1993).
[0081] A processing chamber 9 is defined by a waterproof cover 8
disposed within the main unit 1 so as to enclose the lens LE to be
held by the lens rotary shafts 2R, 2L, as well as the grinder 5. A
nozzle 11 for spraying grinding water extends into the processing
chamber 9. The nozzle 11 is connected to a water suction pump 220
of a tank unit 200 by a water supply hose 221. During the course of
processing of the lens LE, grinding water is sprayed out of the
nozzle 11. The thus-sprayed grinding water and processing debris
250 (grinding wastes) of the lens LE are drained into a grinding
water reservoir tank 210 of the tank unit 200 by way of a drain
hole 8a formed in a lower portion of the cover 8, and a drain hose
201.
[0082] The tank 210 has a cylindrical shape with a bottom, and is
equipped with an unillustrated handle so as to be portable. The
tank 210 is not limited to a cylindrical shape but may be
box-shaped.
[0083] A lid 211 for substantially hermetically sealing the inside
of the tank 210 is removably fitted in an opening section formed in
an upper part of the tank 210. A partition plate 230 to be used for
dividing the inside of the tank 210 into a drainage chamber 210a
and a water suction chamber 210b is fixedly provided in the
vicinity of the center of the lid 211. As shown in FIG. 2, a
clearance (i.e., opening) for ensuring a passage along which
grinding water is to flow is formed between an interior side
surface of the tank 210 and side edges of the partition plate 230
and between an interior bottom surface of the tank 210 and a lower
edge of the partition plate 230 (the drainage chamber 210a and the
water suction chamber 210b are partially connected to each
other).
[0084] A connection opening 212 to which the hose 201 is to be
connected is formed in an area of the lid 211 located above the
drainage chamber 210a. Grinding water introduced by the hose 201 is
drained into the tank 210 by way of the connection opening 212. A
water suction pipe 215 is attached to an area of the lid 211
located above the water suction chamber 210b so as to extend
downward. A filter 216 having a coarse mesh screen is attached to a
water suction opening 215a provided at the lower end of the pipe
215. A water suction hose 217 is connected to an upper end of the
pipe 215 projecting from an upper surface of the lid 211. The other
end of the hose 217 is connected to the pump 220. By driving
operation of the pump 220, the grinding water pumped up (acquired)
by way of the pipe 215 is introduced to the nozzle 11 by way of the
hose 217 and the hose 221. Here, the connection opening 212 and the
water suction opening 215a are preferably located as far as
possible from the partition plate 230.
[0085] The partition plate 230 is provided for purposes of
hindering the processing debris 250 mixed in the drained grinding
water in reaching the water suction opening 215a as well as
facilitating the processing debris 250 to be settled at the bottom
of the tank 210. Accordingly, the partition plate 230 may be
dispensed with.
[0086] The tank unit 200 is equipped with an antifoaming device 300
for eliminating (breaking) bubbles 251 by spraying a fluid (e.g.,
grinding water in this embodiment). The antifoaming device 300 has
a water suction pipe 301 attached to the lid 211 for sucking
grinding water from the water suction chamber 210b; a water suction
pump 305; a water suction hose 303 for connecting the pipe 301 to
the pump 305; a nozzle 310 for spraying the grinding water pumped
by the pump 305 to the drainage chamber 210a; and a water supply
hose 307 for connecting the pump 305 to the nozzle 310. A filter
302 having a coarse mesh screen is attached to a water suction
opening 301a formed at a lower end of the pipe 301.
[0087] The nozzle 310 is attached to an upper part of the partition
plate 230. As shown in FIG. 2, the nozzle 310 has the shape of a
rod. A large number of spray openings 310a are formed in a
longitudinal side surface of the nozzle 310 so as to spray grinding
water in a substantially horizontal direction. The spray openings
310a are provided so as to situate in a position above a water
surface when grinding water is poured (stored) in the tank 210. In
the case of the horizontally long nozzle 310 such as that shown in
FIG. 2, the spray openings 310a are preferably provided in the
entire area occupying from the center of the tank 210 to the
vicinities of the interior side surface of the tank 210 so that
sprayed grinding water can cover, to the extent possible, the
inside of the tank 210 (i.e., the drainage chamber 210a). The
grinding water supplied by the pump 305 by way of the hose 307 is
introduced from a connection opening 311 formed in the vicinity of
the center of the nozzle 310 and sprayed at a predetermined water
pressure by way of the spray openings 310a. The thus-sprayed
grinding water can suppress foaming of the bubbles 251 in the tank
210 (i.e., the drainage chamber 210a) The tank unit 200 is provided
with a processing debris separator 330 which facilitates settlement
of the processing debris 250 and separates grinding water from the
processing debris 250. The processing debris separator 330
comprises a filter 331 provided on the bottom of the tank 210; a
water suction pump 333 for pumping grinding water stored in the
tank 210 by way of the filter 331; a water suction pipe 335 and a
water suction hose 337 for connecting the pump 333 to a hollow
section 339 defined between the filter 331 and the interior bottom
surface of the tank 210; a connection opening 343 formed in a side
surface of the tank 210; and a water-supply hose 341 for connecting
the pump 333 to the connection opening 343.
[0088] A sintered porous member is preferably employed as the
filter 331. The embodiment employs sintered porous plastic member
produced by sintering plastic beads, by virtue of its lightweight,
durability, and superior machinability. The sintered porous plastic
member is formed principally from polyethylene, polypropylene,
ethylene-vinyl-acetate-copo- lymer or the like. The embodiment
employs a filter 331 having a pore size of about 15 .mu.m. The
present inventor conducted tests using a filter having a pore size
of 15 .mu.m and a filter having a pore size of 70 .mu.m. The
grinding water that has passed through the filter having a pore
size of 70 .mu.m was ascertained to cause a whitish turbidity. The
70 .mu.m filter was confirmed to have low filtering accuracy. When
filtering was continued further with the 70 .mu.m filter, minute
processing debris was ascertained to clog the filter, thereby
lowering a filtering rate. In contrast, the filter having a pore
size of 15 .mu.m was ascertained to produce transparent filtered
grinding water and have less effect on a filtering rate even when
filtering operation was performed continuously. Accordingly, use of
a filter having a pore size smaller than 70 .mu.m (e.g., 15 .mu.m
or thereabouts) for the filter 331 is preferable in terms of
filtering accuracy and filtering rate.
[0089] FIG. 3 is an illustration of the filter 331 when viewed from
the bottom surface of the tank 210. The filter 331 is disposed on
the bottom of the tank 210 having a circular cross-sectional shape,
and therefore has the shape of a disk which is substantially
identical in area with the interior bottom surface of the tank 210.
The filter 331 has a thickness of 7 mm. A grid-shaped groove 331a
(the hatched portion in FIG. 3) having a depth of 2 mm is formed in
the lower surface of the filter 331 (i.e., the surface facing the
interior bottom surface of the tank 210). A suction opening 331b to
be connected to the pipe 335 is formed in the center portion of the
groove 331a. The groove 331a serves as a passage along which
filtered grinding water flows, and is formed so that all portions
of the groove 331 communicate with the suction hole 331b. The
filter 331 is placed on the bottom of the tank 210 such that the
outer periphery of the filter 331 is bonded to the interior side
surface of the tank 210 in a shielding manner. The hollow section
339 is established by the groove 331a and the interior bottom
surface of the tank 210, thereby ensuring a passage for sucking or
aspirating filtered grinding water.
[0090] The lower surface of the filter 331 is given a groove
structure for preventing occurrence of fracture or deformation in
the filter 331, which would otherwise be caused by the weight of
the processing debris 250 settled (accumulated) on the upper
surface of the filter 331 and the weight of the grinding water.
Therefore, the groove structure is not inevitable. For instance,
the lower surface of the filter 331 may be made flat, and blocks
may be disposed below the lower surface of the filter 331 so as to
ensure a groove 331a similar to that shown in FIG. 3, thereby
forming the hollow section 339. Alternatively, a cloth filter
having a mesh structure, such as a cotton filter, may be employed
as the filter 331. Even in this case, the only requirement is that
a reinforcement frame be disposed so as to constitute the hollow
section 339.
[0091] If the tank 210 is rectangular in a horizontal
cross-sectional shape, the filter 331 should also be
rectangular.
[0092] Reference numeral 20 designates a control section provided
in the main unit 1. The control section 20 is connected to the
pumps 220, 305, and 333, as well as to a drive unit 22 for rotating
the grinder 5 and a drive unit 21 for moving the carriage section
3.
[0093] Next, use of such an apparatus will be described. First,
grinding water is stored in the tank 210. At this time, a water
surface is set so as to become one to two centimeters lower than
the nozzle 310 of the antifoaming device 300.
[0094] When the main unit 1 has started processing the lens LE, the
control section 20 drives the pump 220, whereby the grinding water
pumped from the water suction chamber 210b is sprayed into the
processing chamber 9 by way of the nozzle 11. The thus-sprayed
grinding water and the resultant processing debris 250 of the lens
LE are drained into the drainage chamber 210a by way of the drain
hole 8a and the hose 201.
[0095] At the time of processing of the lens, the pump 333 is
activated by a switch 25 connected to the control section 20, in
order to promote settlement of the processing debris 250 in the
tank 210. Here, the control section 20 may perform a control
operation so as to drive the pump 333 in conjunction with driving
action of the pump 220.
[0096] When the pump 333 is activated, suction pressure is exerted
on the hollow section 339 formed below the filter 331, whereby the
grinding water stored in the tank 210 is sucked or aspirated and
filtered by way of the filter 331. The grinding water pumped by the
pump 333 is returned to the tank 210 from the connection opening
343 by way of the hose 341. By this suction, the processing debris
250 are attracted toward the filter 331, whereby settlement of the
processing debris 250 is promoted. Further, progress in
solidification of the thus-settled processing debris 250 inhibits
generation of turbidity in the grinding water stored in the tank
210. Hence, a large amount of processing debris 250 can be
accumulated in the tank 210. The processing debris 250 is settled
in order of larger size and weight. Accordingly, large processing
debris 250 is settled (accumulated) first on top of the filter 331.
Hence, clogging of the filter 331 is prevented, and the
thus-settled (accumulated) processing debris 250 acts as a new
filter.
[0097] A permissible storage amount of processing debris 250 in the
tank 210 is such a level that settled processing debris 250 is not
sucked into the suction openings 215a, 301a (via the filters 216,
302). Although it depends on the height of the location where the
suction opening 215a or the like is formed, if about 5 to 6 liters
of processing debris 250 can be settled in a 20-liter tank, about
200 lenses can be processed.
[0098] A filtering rate of the filter 331 is high at the beginning
of a filtering operation. However, as a result of the processing
debris 250 deposited on the filter 331, the filtering rate
decreases. The filtering rate is also sensitive to the performance
of the pump 333. Even when a high-power pump is used as the pump
333, an increase in the quantity of flow (i.e., a flow rate) leads
to a sharp rise in a loss stemming from flow of the grinding water
through the filter 331 (i.e., a flow loss). For this reason,
driving of the pump 333 with appropriate suction is preferable in
terms of preventing overload. The eyeglass lens processing
apparatus adopts as the pump 333 a gear pump using a DC motor, and
the pump is activated with a constant current. In the case of low
filter resistance (flow loss), such a pump achieves at a higher
rotational speed and a larger flow rate. In contrast, when load on
the motor becomes high as a result of increase in filter
resistance, the motor operates at a low current and is controlled
so as to reduce the rotational speed of the motor, thereby
preventing overload.
[0099] With a view toward controlling generation of bubbles during
the course of processing of a plastic lens, an antifoaming agent is
usually added to the grinding water stored in a circulation-type
tank unit. However, when the grinding water including an
antifoaming agent is filtrated using the filter 331, the filtering
performance of the filter 331 is greatly deteriorated by a
surfactant included in the antifoaming agent. The reason for this
is that processing debris enters and clogs the filter 331. In order
to prevent this adverse effect, the eyeglass lens processing
apparatus does not employ any antifoaming agent. However, if no
antifoaming agent is used, processing of few plastic lenses (e.g.,
20 to 30) would involve generation of a large amount of bubbles,
thereby requiring frequent replacement of grinding water.
[0100] The eyeglass lens processing apparatus eliminates the
bubbles 251 by use of an antifoaming device 300. The pump 305 is
activated in conjunction with driving action of the pump 220 so
that the grinding water is sprayed from the spray openings 310a of
the nozzle 310 to the drainage chamber 210a as a shower. The
thus-sprayed water comes into collision with the bubbles at a
predetermined water pressure, thereby breaking the bubbles. In this
way, the processing debris which is included in the bubbles and can
be settled is separated, and the thus-separated debris can be
settled.
[0101] The configuration and layout of the nozzle 310 are not
limited to those described previously. The nozzle 310 may have, for
example, the following configurations. FIGS. 4A and 4B show
modifications of the antifoaming device 300. A nozzle 313 shown in
FIG. 4A has a hemispherical shape, and a large number of spray
openings 313a are formed in the hemispherical surface. A connection
opening 314 is attached to the lid 211 such that the nozzle 313 is
situated in the vicinity of the center of the drainage chamber
210a. The grinding water supplied from the pump 305 is sprayed from
the spray openings 313a of the nozzle 313 by way of the hose 307
and the connection opening 314 to be ejected toward the bubbles in
the tank 210 at a predetermined water pressure. Further, if the
apparatus is provided with a mechanism for rotating the nozzle 313
so as to change the spraying direction, the grinding water will be
sprayed so as to be distributed over the entire inside of the tank
210 (the drainage chamber 210a), thereby eliminating bubbles more
efficiently. A rotary mechanism which undergoes rotation by use of
a motor, water pressure, or reactive force of a jet can be employed
as a mechanism for rotating the nozzle 313.
[0102] A nozzle 320 shown in FIG. 4B is an example of a rotary-type
nozzle utilizing reactive force of a jet. A rotary shaft support
321 is attached to the connection opening 314 shown in FIG. 4A.
Three rod-shaped nozzles 320 are attached to the rotary shaft
support 321. Spray openings 320a are formed in one side surface of
each nozzle 320. The nozzle 320 is rotated along with the rotary
shaft support 321, by means of reactive force of the grinding water
sprayed from the spray openings 320a.
[0103] Even in the case of the nozzle 310 shown in FIGS. 1 and 2,
if a mechanism, such as a motor for pivoting the nozzle 310, is
provided and the angle at which grinding water is to be sprayed
from the spray openings 310a is repeatedly changed between a
horizontal direction and a slightly-downward direction, elimination
of bubbles can be performed more efficiently. The antifoaming
device may be constructed such that bubbles are mechanically
agitated by rotating a rotary member having rod-shaped arms. Such
an antifoaming device breaks bubbles by the arms of the rotary
member coming into collision with the bubbles.
[0104] There will now be described an operation in which the
processing debris 250 stored in the tank 210 is discarded. In this
case, the hose 341 is disconnected from the connection opening 343,
and the grinding water pumped by the pump 333 is drained to the
outside without being returned to the tank 210. The grinding water
pumped by the pump 333 is sufficiently filtered by the filter 331
and hence can be drained directly. Alternatively, the grinding
water may be poured into a separately prepared water receiver tank
for the purpose of recycling. When the pump 333 is activated by
turning on the switch 25, the grinding water stored in the tank 210
is gradually pumped and drained to the outside by way of the filter
331. Finally, moisture contained in the processing debris 250 is
also subjected to suction. When the moisture content in the
processing debris 250 is reduced, the processing debris 250 are
subjected to cracking, whereupon air is directly as pirated by way
of the filter 331. Hence, suction of grinding water becomes
impossible. When no grinding water is drained, the pump 333 is
deactivated.
[0105] When suction of grinding water has become impossible, the
processing debris 250 have a water content of about 40 to 50%, and
the processing debris 250 is solidified. The thus-solidified
processing debris 250 can be readily removed from the tank 210 by
simply turning the tank 210 upside down. The processing debris 250
are discarded while being held in a plastic bag or the like. If the
water content is 50% or less, no water seeps through the processing
debris 250, thereby facilitating discarding of the processing
debris 250. When the water content of the processing debris 250 is
to be decreased further, the processing debris 250 is left so as to
become naturally dried. The thus-discarded processing debris 250 is
to be disposed by an industrial waste disposal company.
[0106] The processing debris separator 330 comprising the filter
331, the pump 333, and the like is provided in the circulation-type
tank unit 200 to be integral with the tank 210. However, the
processing debris separator 330 may be provided separately. FIG. 5
shows an example of such a configuration. Reference numeral 350
designates a cylindrical filter made from sintered porous plastic
member. Lids 352, 353 are fixed to respective ends of the filter
350, thereby defining a hollow section 351 in the filter 350. A
water suction pipe 355 to be connected to the hollow section 351 is
attached to the lid 352. The pipe 355 is connected to a water
suction pump 357 by a water suction hose 356. The grinding water
pumped by the pump 357 is drained by way of a drain hose 358. When
the processing debris 250 accumulated in the tank 210 is discarded,
the filter 350 is inserted into the tank 210. The pump 357 is then
activated, thereby pumping the grinding water in the tank 210 while
filtering and draining, whereby the processing debris 250 can be
separated and removed.
[0107] When separation of grinding water from processing debris is
promoted, a plurality of such filters 350 should be prepared. As a
matter of course, if a plate for sealing purpose is secured on the
bottom of the filter 331 so as to ensure the hollow section 339
through use of the plate-like filter 331 shown in FIGS. 1 and 3,
the filter can be used solely. Alternatively, the filter 350 may be
provided in a tank prepared separately from the tank 210, and
grinding water including the processing debris 250 may be poured
into the tank, thus separating the grinding water from the
processing debris 250.
[0108] <Second Embodiment>
[0109] Another embodiment of the invention will be described
hereinbelow. FIG. 6 is an overall schematic diagram showing an
eyeglass lens processing apparatus according to a second embodiment
of the invention. Those elements which are identical with those
described in connection with the first embodiment are assigned the
same reference numerals.
[0110] A downwardly extending water suction pipe 231 is provided at
a position on one side of the lid 211 opposite from the other side
thereof where the pipe 215 is provided. A water suction opening
231a provided at the lower end of the pipe 231 is extended to a
lower position in the tank 210. A filter 232 having a coarse mesh
screen is attached to the water suction opening 231a so as to sink
to the bottom of the tank 210. Positioning the water suction
opening 231a close to the neighborhood of the bottom of the tank
210 to the extent possible is preferable, and the water suction
opening may be formed in the bottom of the tank 210. In addition,
the filter 232 may be eliminated.
[0111] A water suction hose 233 is connected to an upper end of the
pipe 231 projecting beyond the upper surface of the lid 211. The
other end of the hose 233 is connected to a pressure application
pump 236 for aspirating (pumping) the processing debris 250 along
with grinding water. Moreover, a water supply hose 234 for feeding
the thus-aspirated grinding water and the processing debris 250 is
connected to the pump 236. A drain hole 234a provided at the other
end of the hose 234 is extended to the lid 211 and connected to a
bag-shaped filter 235 provided in the tank 210. Thus, there is
formed a passage to be used for removing and introducing the
processing debris 250 that have settled in the tank 210 along with
the grinding water, which extends from the water suction opening
231a to the filter 235. The pump 236 disposed at a portion of the
passage between the water suction opening 231a and the filter 235
applies a water pressure of about at least 0.05 Mpa onto the
grinding water including the processing debris 250 to charge the
same into the filter 235.
[0112] The filter 235 is constituted of a cotton cloth having a
fine mesh screen. The filter 235 preferably does not permit passage
of processing debris of small particle size (on the order of
micrometers) and prevents inclusion of any processing debris in
filtered water. An opening end of the filter 235 is bundled at the
drain hole 234a of the hose 234 and fastened with a binding band
237. As a result, the filter 235 is connected to the drain opening
234a in a substantially-sealed manner. The filter 235 is separated
from the drain hole 234a by removal of the band 237 and can be
removed from the tank 210.
[0113] The filter 235 is not limited to the shape of a bag and may
have any shape, so long as the filter can form a chamber for
accumulating the processing debris 250 therein.
[0114] The drive unit 21, the drive unit 22, the pump 220, and the
pump 236 are connected to the control section 20.
[0115] Next will be described use of the eyeglass lens processing
apparatus discussed above. Since processing debris 250 of a plastic
lens and a glass lens is, in general, is heavier than water, the
processing debris 250 is settled on the bottom of the tank 210.
When the lenses LE are processed consecutively, the amount of
processing debris 250 settled in the tank 210 increases.
[0116] The pump 236 is activated by the switch 25 (or in
conjunction with the driving action of the pump 220), and the
processing debris 250 settled on the bottom of the tank 210 are
aspirated from the water suction opening 231a by way of the filter
232 along with the grinding water. The grinding water including the
thus-aspirated processing debris 250 flows through the pipe 231 and
the hose 233, is pressurized to a pressure of about 0.06 Mpa by the
pump 236, and is charged into the filter 235 by way of the hose
234. The filter 235 does not permit passage of processing debris of
fine particles and accumulates the debris 250 therein.
Substantially-purified grinding water is discharged to the outside
(into the tank 210) so as to seep through the surface of the filter
235.
[0117] Here, if the filter 235 having a fine mesh screen and high
filtration capability is simply used for filtering grinding water,
much time will be consumed. For example, if the filter 235 is
connected to the hose 201, filtering operation involves consumption
of much time. The hose 201 may become clogged with the grinding
water, which would cause leakage of grinding water into the
processing chamber 9. In contrast, the pump 236 applies a water
pressure of about at least 0.05 Mpa onto the processing water
charged into the filter 235. Hence, a filtering rate can be
increased significantly. Since the filtering rate can be increased
by use of a filter of identical capacity, the rate of recovery of
the processing debris 250 settled in the tank 210 is enhanced.
Further, soil content of the processing water supplied to the main
unit 1 can be decreased.
[0118] If processing of lenses and filtering operation are
performed repeatedly, the processing debris 250 is stacked on the
interior surface of the filter 235. If processing of lenses is
continued further, the thus-stacked processing debris 250 per se
acts as a filter. Hence, processing debris which are smaller than
the screen mesh of the cotton cloth of the filter 235 can be
accumulated in the filter 235. By virtue of the stacked processing
debris acting as a filter of smaller screen mesh, filtering
grinding water requires a longer time. However, water pressure is
exerted on the grinding water charged into the filter 235 by the
pump 236, and hence consumption of along filtering time is not
involved.
[0119] If the pump 236 is operated continuously even after
completion of processing of a lens, the processing debris 250
contained in the grinding water can be accumulated in the filter
235 even when processing of a lens is halted. In this case, the
pump 236 may be controlled using a timer so as to be operated for a
given period of time after completion of processing of a lens and
then be deactivated automatically. The control section 20 may be
given such a timer function. Further, the control section 20 may
repeatedly activate and deactivate the pump 236 after completion of
processing of the lens so as to cause repeated expansion and
contraction of the filter 235, whereby the processing debris 250
stacked on the interior surface of the filter 235 is peeled and
accumulated on the bottom of the filter 235. As a result, even if
clogging has induced a decrease in a filtering rate, the filtering
rate can be restored.
[0120] When the processing debris 250 accumulated in the filter 235
is discarded, the lid 211 is raised, and the filter 235 is removed
from the inside of the tank 210. The band 237 of the drain opening
234a is then removed, and the filter 235 is separated. The
thus-separated filter 235 is further drained, thereby solidifying
the processing debris 250 contained in the filter 235. Hence,
disposal of the processing debris is facilitated. The processing
debris 250 may bed is carded together with the filter 235
containing the processing debris therein. Alternatively, only the
processing debris 250 may be discarded, and the filter 235 may be
reused.
[0121] The filter 235 may be placed at a position above the water
surface of the grinding water stored in the tank 210 so that the
inside of the filter 235 is drained at a time other than when the
pump 230 is activated. In this case, the efficiency of processing
the processing debris 250 can be enhanced.
[0122] FIGS. 7A and 7B show modifications of layout of the filter
235. FIG. 7A shows an example in which the filter 235 is placed
outside (on top of) the tank 210. The grinding water filtered by
the filter 235 is drained to the outside of a tank 260 enclosing
the filter 235. The tank 260 is placed in a position higher than
the tank 210. Hence, the filtered grinding water can be returned to
the tank 210 through natural dropping action (gravity) by way of a
water supply pipe 261 connecting the tank 260 to the tank 210. FIG.
7B shows an example in which the filter 235 is placed outside
(beside) the tank 210. The grinding water filtered by the filter
235 is drained into a tank 263. In this case, a pump 262 is
disposed between a water suction hose 264 and a water supply hose
265 for connecting the tank 263 to the tank 210, thereby returning
the filtered grinding water into the tank 210. FIGS. 7A and 7B show
examples in which the filter 235 is placed outside the tank 210.
Hence, the processing debris 250 can be drained within a short
period of time after deactivation of the pump 230, thereby
enhancing efficiency for processing the processing debris 250.
[0123] In addition, the antifoaming device 300 of the first
embodiment may be disposed in the eyeglass lens processing
apparatus of the second embodiment.
[0124] As has been described, the invention enables easy separation
of grinding water and processing debris in a tank. Hence,
processing debris can be processed readily. Bubbles in a tank can
be reduced without use of an antifoaming agent, and the frequency
of replacement of grinding water can be diminished.
* * * * *