Note: Descriptions are shown in the official language in which they were submitted.
1055254
1 The present invention relates to an abrasive machine for
stones, and more particularly to such machine for grinding-
polishing a flat stone surface with the circle flat surface of a
rotary abrasive disk tool of which level is made adjustable in
relation to the stone surface.
Various kinds of stones such as marble, granite and the like
have been used for various purposes. Depending on the purposes
or uses, a fairly large area of stone plate is subjected to
grinding and polishing at the exterior side thereof, e.g. for
flooring, wall construction and the like.
Hitherto, the abrasion or grinding-polishing of such stone
work-piece has been carried out by grinding the stone surface
with the circle flat surface of a rotating disk grindstone made
of an abrasive material such as particles or chips of natural
or synthetic diamond, carborundum or the like and suitable
binder. Such grindstone is detachably mounted on a disk head
adapted to be rotated and manually moved over the stone surfaceJ
As occasion demands, such grindstone is exchanged with a finer
grinstone one ater another, and finally with a felt for polish-
ing or finishing the stone surface with aid of finely pulverizedabrasive material.
In order to avoid troublesome exchange of the grindstone
and make the abrasion working efficient, it is possible to
arrange a plurality of such grinding machines in series so as
to process the work-piece by and by from rough grinding according
to the first machine to final polishing according to the last
machine. It is invevitable, however, that there is caused
undulation or uneveness more or less on the processed work-piece
surface when the stone plate is of fairly large area relative
to the dimension of the abrasive tool, since a suitable width
of the stone plate is subjected to grinding by manually driving
the rotating abrasive tool to-~nd-fro over the stone plate
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1055ZS4
1 surface, and when such area has been treated the work-piece is
moved so as to further process the new area of the stone plate.
Considerable skill is required for driving such abrasive tool
without causing such uneveness. In order to avoid such undersired
undulation and make the abrasion working more efficient7 it is
considered to enlarge diameter of the disk grindstone as far as
possible. It will be readily understood, however, that there
is naturally a limitation in doing so because of the mechanical
strength of the formed grindstone on the one hand and of rattling
10 of the rotary disk on the other hand.
According to the invention, there are circumferentially
arranged a plurality of rotary abrasive tool disks and the assembly
of these abrasive tools each rotating is adapted to be rotated
so that each abrasive tool is driven to cause rotation and con-
currently revolution. The work-piece is successively fed so
that the surface thereof is subjected to abrasion working of
these rotating and revolving abrasive tools during the slow travel
of the stone plate. Each grindstone of each of said abrasive
tools may be exchanged with finer one, when the rough grinding
20 has been completed. It is preferable, however, to provide
a plurality of such machines in series for proceeding with
continuous grinding and polishing of the work piece fed through
these machines one after anotherO
A principal object of the present invention is, therefore,
to provide an abrasive machine for stones which can obviate
and overcome the disadvantages and faults encountered in the
conventional machine as referred to above.
Further objects of the invention and advantages to be
attained thereby will be appreciated by understanding following
30 explanations which shall be given with reference to one of
typical conventional abrasive machines and a preferred embodiment
as a mere example of the invention, as illustrated in drawings,
1055Z54
1 in which
Fig. 1 is a perspective view of a typical conventional
abrasive machine;
Fig. 2 is a vertical side view of an abrasive machine
according to the invention, some parts thereof being shown in
fragment or section; and
Fig. 3 is a diagrammatic top plan view of the machine as
illustrated in Fig.2 to show an arrangement of grindstones and
mechanisms for causing rotation and revolution of each grindstone.
In Fig. 1, a conventional typical abrasive machine for
stones is generally designated by reference symbol A. The
machine A has a machine body B and a bench or working table C
which is arranged separately from but closely to the machine body
B and on which a stone plate D as work-piece is positioned. The
machine body B comprises an up-right support Bl having a lower
base portion and an upper cylindrical portion, a slidable
member B2 fitted on the upper cylindrical portion of the support
Bl, an abrasive tool B3 detachably mounted with a grindstone
or g~ind~-~ng disk B4, an electric motor B5 for rota~ngly driving
20 the abrasive tool B3 to cause rotation of the grindstone B4, an
articularly connected arm member B6, one end of which is pivotally
connected to the slidable member B2 to serve as a support for
mounting the electric motor B5 and the abrasive tool B3 mounted
with the grindstone B4 at the other or free end thereof, and a
handle B7 for manually operating the machine.
According to the conventional stone abrasive machine A, a
machine operator must, in the first place, operate~the handle
B7 to turn the abrasive tool B3 outside the table C, so that the
work-piece D which may be manually or mechanically fed can be
30 set in position on the table C. Then the operator operates again
the handle B7 to raise the abrasive tool B3 a little, return and
lower the same on the wor~-piece D, so that the grindstone B4
1055254
1 attached to the lower end of the abrasive tool B3 contacts the
outer surface of the work-piece D. In abrasive working operation
of the machine A, the operator turns-on a switch (not shown) to
actuate the electric motor B5 to cause rotation of the abrasive
tool B3 and consequently the grindstone B4 attached thereto
and, at the same time, operates the handle B7 to horizontally
move the abrasive tool B3 on the surface of the work-piece D
to-and-fro to grind and polish the same.
While Figs. 2 and 3 illustrate an embodiment of an abrasive
10 machine according to the present invention. The machine as
generally designated by reference numeral 10 comprises a base 12,
a frame structure 14 mounted on the base 12 and having two
vertical side frames 141,141 and a horizontal top frame 142,
a mechanism 16 arranged on the base 12 to feed a stone plate
18 as work-piece, an abrasion unit 20 arranged above the feeding
mechanism 16 and between the side frames 141,141 of the frame
structure 14, electric motors 22, 24 for actuating the abrasion
unit 20, and means 26 for supporting the abrasion unit 200
The work-piece feeding mechanism 16 may be of a roller
20 conveyor as illustrated, chain conveyor, belt conveyor or the
like but it is preferable to arrange thereon a flat metal or wood
plate 1~1 as a carrier, so that the work-piece can be horizontally
and stably held thereon. The conveyor may be actuated by an
electric motor (not shown), an output shaft of which is connected
to a shaft end 162 of one of the rollers through suitable reduc-
tion gearings (not shown). The other shaft end 163 is connected
to corresponding shaft end of the other rollers through an endless
belt or the like transmission means (not shown) to form the roller
conveyor as the work-piece feeding mechanism 16. The abrasion
30 unit 20 has a head portion 201 carried by the supporting means
26 and a leg portion 202 which comprises a plurality of abrasive
tools 28 arranged along a circle around a central vertical axis
1055254
1 of the abrasion unit 20, each of said abrasive tools 28 having
a grindstone or grinding disk 281 which was made of abrasive
material such as synthetic diamond particles or chips and binder.
According to the abrasive machine 10 of the present invention,
each of the grindstones 281 can be only not rotated but also
revolved and thus it is not always necessary to make the diameter
of each grindstone 281 so large for increasing the abrasion work-
ing efficiency of the machine. This makes the production and
handling of the grindstone 281 quite easy. The abrasion unit
10 supporting means 26 comprises a box-like member 261 for carrying
the abrasion unit 20 and a slidable means 262,262, each of which
may be secured to the box member 261 at one side and secured on
the inner surface of the vertical side frame 141 of the frame
structure 14 at the other side.
In operation of the machine 10 as shown in Figs. 2 and 3,
a machine operator turns-on a switch (not shown) to actuate
the electric motors 22 and 24. An output of the motor 22 is
transmitted to a main shaft 203 of the abrasion unit 20 through
a pulley 221 mounted on an output shaft 222 of the motor 22,
20 another pulley 204 mounted on the main shaft 203 at one end
thereof and an endless belt 30 for mechanically connecting the
pulleys 221 and 204, to cause rotation of a main gear 205
mounted on the main shaft 203 at the other end. Each of a
plurality of small gears 282 for the abrasive tools 28 meshes
with the main gear 205 so as to be rotatingly driven by the main
gear 205. The rotation of each small gear 282 causes rotation
of the concerned grindstone or grinding disk 281 attached to the
lower end of a shaft 283 of each abrasive tool 28, on which the
small gear 281 is securedly mounted. A hollow cylindrical
30 housing 206 for accomodating the main gear 205, small gears 282
and maintaining the shafts 283 of the abrasive tools 28 in
position has a rack 207 on an outer peripheral surface thereof.
1055254
1 The rack 207 meshes with a pinion 32 rotatingly driven by the
electric motor 24 through a coupling means 34, to cause revolution
of each abrasive tools 28 and more particularly each rotary
grindstone 281. The work-piece 18 can continuously be fed by
the work-piece feeding mechanism 16, as stated hereinbefore, to
grind and/or polish the outer surface of the work-piece 18 by the
rotating and revolving grindstones 281.
A level of the abrasion unit 20 and more particularly a gap
or distance between the lower end surface of the grindstones
10 281 and the upper suface of the work-piece 18 can be adjusted
by operating the slidable means 262, depending on the thickness
of work-piece to be treated.
The grindstones 281 for each abrasion unit 20 may have same
or different roughness. The roughness of the grindstones 281
may be selected depending on surface characteristics and kind
of work-piece 18 to be worked.
The abrasive machine 10 according to the present invention
may be modified to a continuous abrasive machine, by subsequently
feeding the work-pieces 18 therein with the aid of the feeding
20 mechanism 16 and by arranging a plurality of abrasive units 20
in series so that roughness of the grindstones of the respective
unit are made gradually finer. According to such machine, the
work-pieces can continuQusly be worked from rough grinding to
polishing or finishing, whereby the working ability can consider-
ably be improved in comparison with any conventional machine.
The invention will now be further explained with reference
to an example showing the grinding-polishing ability o~ the
continuous abrasive machine according to the present invention.
Example
A plurality of cut plates (width: 60 cm) of granite from
Paochon (Korea) was subsequently fed into the following abrasive
machine at feeding velocity of 1.5 m/min. which means the working
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1055Z54
1 area is 54 m2/hr., to continuously grind and polish one side
surface of the stone plate.
Abrasive Machine
The abrasive machine used was substantially same with that
as illustrated in Figs. 2 and 3 and had following measures.
Number of abrasive units: 15
Number of abrasive tools or grindstones for each unit: 12
Diameter of each grindstone: 12 cm
Abrasive material for each grindstone excepting the final
unit which uses a conventional felt for buffing:
synthetic diamond particle or chip
Particle size of abrasive material for grindstones:
For 1st and 2nd abrasive units: 40 to 50 meshes
(metal bonded)
For 3rd and 4th abrasive units: 60 to 80 meshes
(metal bonded)
For 5th and 6th abrasive units:100 to 120 meshes
(metal bonded)
For 7th and 8th abrasive units:170 to 200 meshes
(metal bonded)
For 9th and 10th abrasive units:170 to 200 meshes
(resin bonded)
For 11th and 12th abrasive units: 12 to 25 ~ (resin bonded)
For 13th!-~and ~4th abrasive un~ts: 4 to 8~ (resin bonded)
The stone plates were ground by thickness of 1.0 mm when
those had been passed through the second abrasive unit and the
thickness of each plate were finally reduced by 3.0 mm. The
surface of each worked plate showed a very high flatness and
very fine burnish.
