Note: Descriptions are shown in the official language in which they were submitted.
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TITL~ OF ~ . IllVI~ TIO2~:
~rinding ivlachine and Crinding llethod
Field of the Invention
The present invention relates to a grinding machine and
a grincling method for grining the impression or cavity surfaces
in dies.
])escription of the ~.elated Art
The grinding machines or performing a grinding operation
in which a horizontally extended upper supporting frame is supported
by the columns of a frame in such a way it is movable forwardl~ or
baclcwardly; a moving body is mounted on the upper supporting frame
in such a way that it is transversely movable;ancl a grindstone
head is mounted on the l~oving body in such a way that the head
is vertical movable have been well known to those skilled in the
art.
In the grinding machines of the type described above,
the uppper frame together witll tlle moving l~ody and the ~rindstone
head are moved on the columns so that the position of tlle grindstone
llead is varied in tlle forward or backward direction. Therefore,
the guide and supporting frames for the upper frame must be
disposed on both sides of the frame,so that the ~rinding machines
are complicated in construction. ~urthermore,sucll guide and supporting
frames close both of the right an~ left sides of the frame,so that
there exists a problem tllat it is ver~ cumbe~soMe to handle a worlcpiece
'-or inserting it into and removing it from the interior of the
frame. In addition,in the case of grinding the surfaces having
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complex shapes as in the cases of dies,the grindstone must be
pressed against a surface to be ground and displaced follo~7ing
the variation in shape of the surface to be ground.
It is also known to those skilled in the art a grinding
machine o~ the type in which a mounting member is vertically
movably supported on a moving body whicll is supported on the frame
n such a way that the moving body can move in mutually perpendicular
in a_horizontal plane/
directions/and tl~e grindstone hea(l is vertically movably mounted
on tlle mounting member.
IIowever,in the case of grinding a vertically e.~tended
sur~ace to be ground by such grinding machine,when a new
surface is to be ground after grinding of a surface, the direction
or angle of the grindstone mouned on the grinding llead must be
varied. Xspecially when the surface portions are ~rmed continuously
each other in a curved state and are extended vertically, the
grindstone mounting direction or angle is changed very frequently
and repeatedly,so that there exists the problem that the grinding
e~ficiency is extremely decreased.
In this ~rinding machine,the changirlg in position in the
vertical direction of the grindstone head is limited only to a
position adjacent to the grindstone head. Therefore,there exists
the problem that the displacement stroke of the grindstone head
is limited,so that the grinding machine cannot grind the relatively
large-si~ed workpieces.
It is also known to those skilled in the art a grinding
machine in which the mounting member is vertivally movably mounted
on the moving body which in turn is supported by the f~ame in such a
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way that it is movable in mutually perpendicular directions and
the grinclstone head is mo~mted on the mounting member in such
a way that the head can rotate about not only the traversely
horizontally exter~-ded axis but also the axis which is perpendicular
to the first-mentioned axis and is extended forwardly and backwardly.
~ Iowever,in this grinding machine, the grindstone head
is rotatably mounted on the mounting member which in turn is
vertically movable and the center of rotation of the grindstone
head is displaced in response to the movement in the vertical
direction of the mounting member. Therefore,the distance between
the grindstone head and the center of rotation thereof is always
maintained constant. As a result, the range of the displacement
of the grindstone head is limited of its rotation range and is narrow,
so that there exists the problem that the grinstone cannot reach
an elongated deep portion of a workpiece.
Meanwhile,the grinding tool
is disclosed in Japanese Utility ~odel Publication
l~1O.37-2028. A ball-and-socket joint is attached to power transmission
means whicll in turn is attached to the leading end of the driving
shaft and a plurality of projections are e~uiangularly extended
along a circumferential direction from the inner wall of the
spherical hole of the ball-and-socket joint. Furthermore, the
ball of the ball-and-socket joint which is formed with enlongated
sliding grooves adapted to engage with the projections,respectively,
is fitted into the spherical hole in such a way that it becomes
impossible to remove tl~e ball out of the spherical hole. A pad
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provided with a sheet of sandpaper is securely attached with screws
with a flat head to the lower end of tlle leg portion of the ball-
and-soclcet joint. In addition, a compression spring is loaded
between the pad plate and the power transmission means so that
the grinding operation can be easily carried out in response to
the projections and valleys or recesses of a surface to be ground
without changing the angle of inclination of the driving
shaft.
With the grinding tool of the type described above,
the force which presses the grinding machine to the surface to be
ground acts on the ball-and-socket joint
at the vertex of the inner wall of the ball-shaped hole of the
ball-and-socket joiint spaced apart from the sandpaper. Therefore,
when the pad plates follows the projections and valleys on the
surface to be ground so that the center
axis of the driving shaft crosses at an angle with the center axis
of the pad plate,the pad plate tends to move away from the surface
to be ground due to ~e gre~t~ distance from the top of the ball-and-socket
joint to the sandpaper. In order to overcome this problem,a bias
spring is provided to bias the pad plate or the diameter of the
pad plate is selected to be by far greater than the distance
between the top of tlle ball-and-socket joint and the sandpaper.
Such grinding tools have the problems that the number of
component parts is increased,the construction is complicated and
their assembly is cumbersome.A further problem is that it is
difficult to decrease the diameter of the pad plate,so that the
projections and valleys having relatively small curvature of radius
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cannot be ground satisfactorily in practice.
S~R~ OF THE INVENTIO~:
One of the objects of the present invention is to provide
a grinding machine whicll can facilitate the handling of a worlcpiece
including the insertion and the discllarge after the completion
of the grinding process.
A further object of the present invention is to provide
a grinding machine whicll can easily grind the workpiecesof various
sizes.
A further object of the present invention is to provide
a grinding machine which can sufficiently make a grindstone reach
into the deepest portion of a surface to be ground.
A further object of the present invention is to provide
a grinding machine which can sequentially grind the surface to be
ground of a workpiece.
A further object of the present invention is to provide
a grinding machine which can efficiently grind the surface to be
ground of a workpiece.
A further object of the present invention is to provide
a grinding machine and a grinding method in which the switching
between the energized state and the de-energized state of a
pressure application cylinder can be made in a simple manner.
A further object of the present invention is to provide
a grinding machine and a grinding method which can easily store
the data concerning the grinding paths.
A further object of the present invention is to provide a
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grinding machine and a grinding method which can accomplish the
grinding operation with a higll degree of efficiency without the
need of indicating a grinding path at each grinding step.
A further object of the present invention is to provide
a grinding method whicl-l can eliminate the displacement of a grindstone
head from the end of its displacement to the starting point thereof
after the completion of the teaching step,whererby the grinding
operation is much facilitated.
A further object of the present invention is to provide
a grinding machine and a grinding method which can substantially
prevent a grindstone from striking against the projections of a
surface to be ground.
A further object of the present invention is toprov~de
a grinding machine and a grinding method which can eliminate the
grinding operation in the case whenoverload is acting on a grindstone
and the repetition of the grinding operation in accordance with
an erratic data of grinding paths,whereby the safe grinding
operation can be ensured.
A further object of the present invention is to provide
a grinding machine which can grind a surface to be ground uniformly
and with a high degree of accuracy without causing an~J grinding
variations such as insufficient grinding of the recessed portions
of the surface to be ground and excessive grinding of the projected
portions thereof.
A further object oE the present invention is to provide
a grinding machine which can reduce the transmission of vibrations
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of a grindstone to the frame to a minimum.
A further object of the present invention is to provide
a grinding machine which can easily grind even a small portion
of a surface to be ground and having a complicated pattern.
A further object of the present invention is to provide
a grinding machine which can simplify the constructions of a
moving body and a frame.
A further object of the present invention is to improve
the capability of a grindstone following a surface to be ground,
whereby the grinding operation can be accomplished smoothly.
A further object of the present invention is to provide
a grinding machine which can cause a grindstone to follow the
projections and valleys each having a relatively small radius of
curvature so that the uniform grinding operation can be ensured.
A further object of the present invention is to provide
a grinding machine which can avoid the interfer-ence between an air
cylinder and a rotation mechanism due to the rotation of a grindstone
head.
A further object of the present invention is to provide
a grinding machine which can eliminate the step carried by an
operator for changing the attachment conditions of a grindstone
to a grindstone head depending upon the direction of a surface to be
ground,whereby the efficiency of the grinding operation can be improved.
A further object of the present invention is to provide
a grinding machine and a grinding method which,in case of the
displacement of a grindstone along an erratic path in the teaching
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step,can eliminate the step for repeating the teaching step from
its begining and also eliminate a waste of a machining time
in the playback step and the variations in respective erratic
grinding paths due to the excessive grinding.
A further object of the present invention is to provide
a grinding machine and a grinding method which can permit the smooth
continuation of the teaching step without any interruption.
A further object of the present invention is to provide
a grinding machine and a grinding method which can permit the
simple and quic~ correction operation in the teaching step.
To the above and other ends,the present invention provides
a grinding machine characterized ~y comprising a pair of upright
columns installed in opposing relationship with eacll other,a
supporting frame extended between the upper ends of the upright
columns,a first displacement mechanism mounted on the supporting
frame in such a way that it is reciprocably movable in the horizontal
direction,a second displacement mechanism which is mounted on the
first displacement mechanism and is adapted to reciprocably move
in the horizontal direction perpendicular to the direction of the
displacement of the first displacement mechanism,a third displacement
mechanism mounted on the second displacement mechanism for reciprocable
movement in the vertical direction and a grindstone head which
has a grindstone and is mounted on the third displacement mechanism.
Moreover the present invention provides a grinding method characterized
by the steps of storing a predetermined grinding path by displacing
a grindstone head along a surface to be ground by a teaching mechanism and
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causing the gri rl(~sLone to repeatedly reciprocate within a
predetermined range according to the grinding paths stored in
a stoage device.
The other objects of the present invention will become
apparent from the preferred embodiments thereof to be described
in detail hereinafter and from the scope of the claims and
various novel features of the present invention which are not
described in this specification will become apparent to those
skilled in the art when the present invention is carried out.
BRIEF DESCRIPTION OF THE DRAWINGS:
Fig.l is a front view with parts broken away and parts
shown in full of a first embodiment of the present inven~ion;
Fig.2 is a sectional view taken along the line II-II of
Fig.l;
Fig.3 is a partial sectional view,on enlarged scale,
taken along the line III-III of Fig.2;
Fig.4 is a front view with parts broken away and parts
shown in full of a second embodiment of the present invention;
Fig.5 is a sectional view taken along the line V-V of
Fig.4;
Fig.6 is a isectional view illustrating on an enlarged
scale the construction of a grindstone head;
Fig. 7 is a side view thereof also illustrating the
construction of the grindstone head;
/ Fig.~ is a diagram of an air supply control circuit
for controlling the actuating of an air cylinder which pushes a
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grindstone;
Fig.9 is a front view,on enlarged scale,of a control
panel;
Fig.10 is a front view,on enlarged scale,of a teaching
device;
Fig.ll is a block diagram o the control circuit;
Fig.12 is a front view with parts broken away and parts
shown in full of a fourth embodiment or a die polishing machine
in accordance with the present invention;
Fig.13 is a front view illustrating another modification;
Fig.14 is a front view of a fifth embodiment or a die
polishing machine in accordance with the present invention;
Fig. 15 is a longitudinal sectional view of a sixth
embodiment or a grinding tool in accordance with the present
invention;
Fig. 16iS a top view of a grindstone;
Fig. 17 is a front view of a die grinding machine;
Fig. l8 is a longltudinal sectional view illustrating
a modification of the grinding tool;
Fig. 19is a front view with parts broken away and parts
shown in full of a grindstone head of a seventh embodiment in accordance
with the present invention;
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Fig. 20 is a front view of a grinding machine;
Fig. 21 is a sectional view, on enlarged scale,
taken along the line XXI-XXI of Fig. 19;
Fig. 22 is a top view of a die used to explain
the mode of grinding operation thereof;
Fig. 23 is a front view of a grinding machine;
Figs. 24 and 25 are front views illustrating
attachments, respectively, each equipped with a
grindstone;
Fig. 26 is a perspective view of an eighth
embodiment or a die polishing machine in accordance
with the present invention;
Fig. 27 is a top view of the die used to explain
the teaching step; and
Fig. 28 is a block diagram of a control circuit
for die polishing machine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
Now referring to Figs. 1-3, a first embodiment of
a grinding machine in accordance with the present
invention will be described in detail hereinafter.
The frame 1 of the grinding machine has a
gantry-like construction consisting of a horizontally
elongated box-shaped base 2, a pair of upright columns
3 extended from the surface of the base 2 adjacent the
lateral sides, respectively, thereof and a horizontally
extended upper supporting frame 4 extended between the
upper ends of the upright columns 3 and securely
3~ attached thereto. Each of the upright columns 3
comprises a large-diameter stationary
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cylinder 3a, a gIlide cylinder 3b fitte(l into and securely attachetl
to the upper end l)ortion of the large-(liameter stationary cyliTIder
3a and a small-cliaIlIeter movaI~le cylinder 3c telescopically fitted
into the guicle c~Jlinder 3c for vertical movement A pair of sliding
guides 5 and 6 are disposed on the upper and lower surfaces of
the upper supporting frar,~e 4 along each oE tlIe front and rear
sides thereof
I7itIlin each of the upriglIt columns 3 is vertically extended
a threaded lif t rod 7 for rotation and the upper end of the
threaded rod 7 is threadably engaged with the bottom of the movable
cylinder 3c A reversible lift motor ~ is mounted in the base 2
The motor 8 is drivingly coupled through a driving pulley~ 9, an e~dless
belt 10, a driven pulley 11, a recIuction gear 12, right and left
transmission shafts 13 extended horizontally, driving gears 14
antl a driven gears 15 to the threaded rods 7 so that upon rotation
of tlle motor 8, the threaded rods 7 are rotatecl,whereby the movable
cylinders 3c are move(I vertically in unison with the upper supporting
frame 4 A moving body 15is supported on the upper supporting frame
4 of the frame 1 and is guided by the guides 5 and 6 in such a
way that the moving body 16 is moved in the horizontal or X-
dlrection An Y.-direction movement lead screw 17 is rotatably
mounted on the bottom of the upper supporting frame 4 and is
threadably engaged with a threaded ball member 1~ within the X-direction
moving bocly 16 An X direction reversible motor 19 is mounted at
the left end of the upper supporting member 4.Upon rotation or
the motor 19, the lead screw 17 is rotatecl through a transmission
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shaft 20 so tllat the ~ direction moving body 16 is caused to move
to the left or rigllt ( or in the horizontal direction).
A Y-direction moving body 21 substantially U-shaped in
cross section is supported by the X-direction moving body 16
and is guided by a pair of right and left guide 22 extended
througll the ,~-direction moving body 16 so that the Y-~irection
moving body 21 can be moved forwardly or baclcwardly. A Y-direction
lead screw 23 is rotatably mounted on the Y-direction moving
body 21 and is threadably engaged with an internally threaded
ball member 24 within the ~-direction moving body 16. A Y direction
reversible motor 25 is mounted at the rear end of the Y direction
moving body 21. Upon rotation of the Y direction motor 25, the
lead screw 23 is rotated so that the 'I-direction moving body 21
is moved forwardly or backwardly.
A cylindrical gear case 26 is attached to the front end
of the Y-direction moving body 21.A first rotating body 27 is
supported through an annular guide rail 2~ at the front end surface
of the gear case 26 in such a way that the first rotating body 27
can rotate about a horizontal axis extended forwardly and baclcwardly.
A first rotation operation handle 29 is disposed on the right side
of the gear case 26. Upon rotation of the operation handle 29,
the first rotating body 27 is caused to rotate through a predetermined
angle through a worm 30 and a worm wheel 31.
A pair of projected walls 27a are extended forwardly of
the front surface of the first rotating body 27 and a second rotating
body 32 is supported between the pair of extended walls 27a through
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a pair of pins 33 in such a way that tlle second rotating body 32
is rotatable about an axis which is perpendicu]ar to the axis of
rotation of the first rotating bocly 27 and is extended both in
the right and left directions. A second rotating handle 34 is
disposed on the right side of the first rotating body 27. Upon
the rotation of tl~e handle 34,the second rotating body 32 is caused
to rotate tl~rough a predetermined angle through a worm 35 and a
worm wheel 36.
A Z-direction moving body 37 in the form of a cylinder
is extended through the second rotating body 32 and is guided by
a guide 38 for vertical movement. A cylinder 39 is securely mounted
on the second rotating body 32 so as to surround the Z-direction
moving body 37. A Z-direction reversible motor 40 is mounted on
the upper end of the supporting cylinder 39. A Z-direction lead
screw 41 is extended downwardly from the motor 40 and is threadably
engaged with an internally threaded ball member 42 of the Z-direction
moving body 37.Upon rotation of the Z-direction motor 40,the lead
screw 41 is rotated so that the Z-direction moving body 37 is
caused to move vertically.
The upper end of a guide and supporting sha~t 43 is
attached to the lower end of the Z direction moving body 37 and
is extended downwardly through a coupling 44. A sliding body 45
is supported by the guide and supporting shaft 43 for vertical
movement. A supporting arm 46 is swingably or pivotably pivoted
to one side of the sliding body 45 with a pivot pin 47 extended
horizontally. A grindstone head 48 is pivotably attached to the
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end of the supporting arm 46 with a pivot pin 49 extended horizontally.
A grindstone 50 is detachably attached to the lower end
portion of the grindstone head 4~. Upon energization of an air
motor mounted in the grindsone head 4~,the grindstone 50 is
reciprocated fowardly and backwardly tllrougll an oscillation generator
51. In this case,it should be noted that instead of causing the
swinging oscillation,the grindstone 50 may be rotated. A cylinder
52 is disposed at one side of the sliding body 45 and the upper
end of its piston xod 53 is securely attached to the coupling 44.
Upon energization of the air cylinder 52,the sliding body 45
is forcibly moved downwardly so that the grindstone 50 is pressed
against the surface to be ground of a workpiecelOlto be described
in detail hereinafter.
~ leanwhile a pair of forwardly and backwardly extended
guide rails 54 is laid on the base 2 of the frame 1 between the
upright columns 3. A table 55 rides on the guide rails 54 through
a plurality of wheels 56 in such a way that the table 55 can
move forwardly or baclcwardly. A workpiece 101 such as a die
is mounted on the upper surface of the table 55. The table 55
is moved forwardly or bac~wardly by a motor (not shown) so that
the workpiecellis brought to a position immediately below the
grindstone 50;that is,the grinding position or moved away therefrom.
Next the mode of operation of the grinding ~achine with
the above-described construction will be described.
In case of grinding the surface to be ground of the workpiece
101 such as the surface of an impression or cavity in a die with the
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grinding machine of the type described above,the workpiece 101
is mounted on the table 55 and is brought to the grinding position
immediately below the grindstone 50 as shown in Fig.2. In this
case,as described above,the frame 1 has the gantry-like construction
consisting of the base 2,the pair of upright columns 3 and the
upper supporting frame 4 so that the whole right and left sides
of the frame 1 are openedJso that the handling of the workpiece
101 including the loading and unloading it into and out of the
frame 1 is much facilitated.
Thereafter upon rotation of the lift motor ~, the lead
screws 7 in both the upright columns 3 are rotated so that the
uprigllt columns 3 are moved vertically and consequently the upper
supporting frame 4 is also moved vertically. l~len the X-, YT and
Z-direction motors 19,25 and 40 are energized, the lead screws
17,23 and 41 which are drivingly coupled with these motors,respectively,
are rotated so that the X-,Y- and Z-direction moving bodies 16,21
and 37 are displaced in the ,~,Y and Z directions,respectively,and
consequently the grindstone head 48 is caused to displace itself
in the right and left direction ( or the lateral direction in
parallel with the upper supporting frame 4),in the forward and
backward direction ( or the longitudinal direction in parallel
with the guide rails 54) and in the vertical direction ( in parallel
with the upright columns 3). In this manner, the grindstone head
48 can be displaced to a position adjacent to the surface to be
ground of the workpiece 101 in a simple manner.In this case,it
should be noted that the range of the vertical displacement o~
the grindstone head 48 can be made large due to the adjustment
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of the telescopic movement of the upright columns 3 and due to
the adjustment of tlle displacement of the moving body 37 in the
Z-direction. As a result,the grinding machine can grind workpieces
in various si~es and shapes.
Iinlen the first and second handles 29 and 34 are rotated,
he Z-direction moving body 37 is rotated in the left or right direction
lon~itudinal/
about the ~ axis (extended for~ardly or backwardly~and also in
the forward or backward direction about the lateral axis. In this
case, the center of rotation in both directions of the Z-direction
moving body 37 is always maintained at a predetermined position so
that the vertical displacement takes place while the Z-direction
moving body 37 is rotated in an arbitrary direction. Therefore,the
grindstone head 48 can be displaced over a wide range so that it
can reach a narrow deep portion of the surface to be ground of
the workpiece 101.
~ hen the air cylinder 52 is energized under these con-
ditions,the grindstone head 48 is further biased to move downwardly
so that the grindstone 50 is pressed against the surface to be
ground of the workpiece 101. When the air motor in the grindstone
head 4~ is energized under these conditions,the grindstone 50 is
forced to reciprocate forwardly and backwardly through the oscillation
generator 51. Therefore,the grindstone 50 can be displaced arbitrarily
in the lateral,longitudinal or vertical direction along the surface
to be ground of the workpiece lOl,whereby the surface of the workpiece
101 can be successively ground.
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~ eferring ne~t to Fig.s.4-8,a secon(l embodiment of the
present invention will be described in detail. In the second
embodiment,the ~-,Y- and Z- direction motors are servomotors
20~,213 and 220 and the workpiece 101 is also mounted on a table
225.
First tlle consturction of a grindstone head 219 will be
described in detail with reference to Figs.6 and 7. A guide and
supporting rod 231 is attached to the lower end of a Z-direction
moving body 21~ through a rotary coupling 232 consisting of a
stationary disk 233 and a movable disk 234. A sliding body 235
is vertically movably supported by the guide and supporting rod
231. A supporting arm 236 is pivotably attached to one side of
the sliding body 235 with a laterally extended pivot pin 237.
An air motor 233 is pivotably attached to the lower end of the supporting
arm 236 through a supporting cylinder 240 with a pivot pin 239
laterally extended. The air motor 238 is always maintained in
an upright position under the forces of a plurality of springs
241 as shown in Fig.6. A grindstone 242 is attached to the lower
end of the supporting cylinder 240 through an oscillation generator
243. Upon rotation of the air motor 238,the grindstone 242 is
forced to reciprocate forwardly and backwardly through the oscillation
generator 243.
As best shown in Fig.6,a first air cylinder 244 which is
pressure application means is disposed on one side of the sliding
body 235. The upper end of the piston rod 246 extended from the
piston 245 of the air cylinder 244 is securely attached to the
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rotary disk 234 of the rotary coupling 232. Of the three ,~-,Y- and
Z-directions of the displacement of the grindstone head 219,two
directions ( for instance,X- and Y-directions) are selected and
when,upon energization of the ~- and Y-direction motors 203 and
213,the grindstone head 219 is displaced in both the X- and Y-
directions so as to grind the surface to be ground 104 of the
impression or cavity in the workpiece lOl,the sliding body 235 is
biased to move in the remaining direction;that is,in the Z-direction
( in the downward direction)/
/under-lhe-l~orc-e-o-f-rhe flrs~ air cylinder 244 so that the grindstone
242 is pressed against the surface to be ground 104.
As shown in Fig.7,a second cylinder 247 which is pressure
~ throughl
application means is pivitably attacl-ed t~-a mounting plate 248
with a pivot pin 249 to the rear end portion of the sliding body
235 . The le.ading end of the rod 251 extended from the piston 250
of the second :air cylinder 247 is connected through a connecting
member 252 to the supporting arm 236.A spring stopper 253 is attached
through a supporting member 254 to the front portion of the sliding
body 235 for engagement with the supporting arm 236,thereby restricing
the rest position thereof. In .case of grinding the surface to be
ground 104 at the bottom of the workpiece 101 by displacing the
grindstone head 219 in both the ~- and Y-directions as described
above, the second air cylinder 247 is maintained in the de-energized
state and because of the engagement of the supporting arm 236 with
the spring stopper 253,the supporting arm 236 is maintained in the
substantially vertical rest position as indicated by the solid lines
in Fig.7.
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~ len the ~- and Z-directions are selected as two
directions in which the head 219 is displaced and furthermore
when the grindstone head 219 is maintained through the rotary coupling
232 at the position indicatd in Figs.5 and 7 or at the position
angularly spaced apart therefrom by 180 so as to grind the front
and rear surfaces to be ground 103 of the workpiece 101, the
second air cylinder 247 is switched to the energized mode so that
the supporting arm 236 is rotated in the counterclockwise direction
in Fig.7,whereby the grindstone 242 is pressed against the forward
or bacl;ward surface to be ground 103 of the workpiece lOl. In
additionlwhen the Y- and Z-directions are selected as the directions
in which the grindstone head 219 is displaced and furthermore when
the grindstone head 219 is rotated from the position indicated in
Figs.5 and 7 through the rotary coupling 232 in the clockwise or
counterclockwise direction by 90 so as to grind the right or left
surface to be ground 102 of the workpiece lOl,the second air cylinder
247 is also switched into the energized state so that the supporting
arm 236 is rotated and consequently the grindstone 242 is pressed
against the right or left surface to be ground 102.
~ eferring back to Fig.4,a control panel 257 having
switches and the like for selectlng the direction of the displacement
of the grindstone head 219 is suspended through a supporting rod 258
on the right side of the frame 201. The grinding machine is further
equipped with a teaching device 259 for previously storing the
grinding paths traced by the grindstone head 219 manually.
Next referring to Fig.~,the control circuit for controlling
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the first and second air cylinders 244 and 247 will be described
below.
In the control circuit as shown in Fig.o,an air source261
is co~nunicated witl two pairs o~ air supply lines 262 and 263;and
264 and 265. Directional control-valves 266a,266b,267a and 267b
for controlling the air supply and discharge are provided in the
air supply lines 262 and 264. Furthermore,pressure cotnrol valves
~6~,269,270 and 271 are provided into the air supply lines 262-
265,respectively. In the pair of air supply lines 262 and 263,
one pressure cotnrol valve 268 is set at a pressure including a
pressure compensation component for compensating for the weight of
the sliding body 235 which is lower than a set point o~ the
other pressure control valve 269. In the other pair of air supply
lines 264 and 265,one pressure cotnrol valve 270 is set at a
pressure higher than a set point o~ the other pressure control valve 271.
The air is supplied into one cylinder chamber of the first
air cylinder 244 through the directional control valve 266a and
the pressure control valve 260 illcluded in the air supply line 262
while the air is supplied into the other cylinder chamber through
the pressure control valve 269. The air is charged into one cylinder
chamber of the second air cylinder 247 through the directional
control valve 266b and the pressure control valve 270
of the air supply line 264 while the air is charged into the
other cylinder chamber through the pressure control valve 271
of the air supply line 265.
~ e~t the mode of operation of the grinding machine with
the above-mentioned construction will be described below.
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1 3 1 330~
First,as shown in Fig.5,the workpiece 101 such as a die
is mounted on the table 225 and is moved to and located at the
grinding position immediately below the grindstone head 219. In
case of grinding the bottom surface 104 of the workpiece lOl,the
switches on the control panel 257 are so actuated that the two
driections;that is,the X- and Y-directions in which the grindstone
head 219 moves are selected. Then, as shown in Fig. 8, the directional
control valves 266a an~ 267b are turned on while the directional
control valves 266b and 267a are turned off.Then the air cylinder
244 is energized while the second air cylinder 247 remains in the
inoperative or de-energized state. The first air cylinder 244
causes the grindstone 242 to press against the bottom surface
104 at a predetermined pressure in the do~ward direction. Under
these conditions,the air motor 23~ is energized so that the grindstone
242 is caused to reciprocate while the grlndstone head 219 is
displaced in a desired direction in the ~- and Y-directions
by the ~- and Y-direction motors 20~ and 213,whereby the grindstone
242 grinds the bottom surface 104.
In this case,the pressing force exerted to the grindstone
242 from the first air cylinder 244 is determined depending upon
the dif~erence in pressure set point between the pressure control
valves 268 and 269. ~nlen the surface to be ground 104 is smooth,
the pressure e~erted to the grindstone 242 is maintained at a pre-
determined level,but when the projected portions of the surface 104
to be ground is ground,the pressure e,~erted to the grindstone 242
is set at a low level while when the recessed portions are ground,
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the pressure applied to the grindstone 242 is set at a hi~h level.
The setting of tlle pressures exerted to the grindstone 242 may be
made by a computer in the teaching step ~y use of the teaching
device 259.
I~ext in case of grinding the forward or baclcward
surface to be ground 103 of the workpiece lOl,the grindstone head
219 is rotated through the rotary coupling 232 to the position
indicated in Figs.5 and 7 ~r ~o tha~ rotc~t~d: by 180. Mext,the Y~ and
Z-directions are selected as the directions in which the grindstone
head 219 is displaced. Then the control valves 266a and 267b
are turned off while the ~ control valves 266b and 267a are turned
on. As a result, the first air cylinder 244 is de-energi~ed while
the second air cylinder 247 is energized so that the grindstone
242 is pressed against the forward or baclcward surface to be ground
103 under a predetermined pressure. Under these conditions,the
grindstone 242 is caused to reciprocate while the grindstone head
219 is displaced in both the X- and Z-directions by the ~Y- and Z-
direction motors 20~ and 220,whereby the grindstone 242 grinds
the forward or baclcward surface 103 of the workpiece 101.
Furthermore,in the case of grinding the right or left
surface to be ground 102 of the workpiece lOl,the grindstone head
219 is rotated from the position indicated in Figs.5 and 7 to the
position angularly displaced from the first-mentioned position
by 90 in the ciockwise or counterclockwise direction. Mext the
Y- and Z-directions are selected as the directions in which the
grindstone head 219 is displaced. Then,as described above, the
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control valves 266a and 267b are turned off while the
control valves 266b and 267a are turned on. As a result,the first
air cylinder 244 is de-energized while the second air cylinder
247 is energized so that the grindstone 242 is pressed against
the right or left surface 102 to be ground at a predetermined
pressure. Under these conditions,the grindstone 242 is reciprocated
while the grindstone head 219 is displaced in the Y- and Z-directions
by the Y- and Z-direction motors 213 and 220,whereby the grinstone
242 grinds the right or left sur~ace 102 to be ground.
As described above,according to the present invention,
of the three directions;that is,the Y-,Y- and Z-directions, two
directions in which the grindstone head 219 is displaced are
selected while in the remaining one direction,the grindstone 242
is pressed against the surface to be ground 102,103 or 104 under
a predetermined pressure so that the grinding of the surfaces to be
ground can be accomplished very efficiently. The switching between
the energized state and the de-energized state of each of the
pressure application air cylinders 244 and 247 can be easily
accomplished in response to tile OM-OFF operations of the control
valves 266a,266b,267a and 267b.
So far it has been described that the control valves
266a,266b,267a and 267b are alternately turned on so that the
first and second air cylinders 244 and 247 are alternately energized,
but it is to be understood that all the flowcontrol valves are
simultaneously turned on so that the both the air cylinders 244 and
247 are concurrently energized,thereby accomplishing the grinding
operation. Moreover, the control valves 266a, 266b, 267a, 267b, can be
omitted from the circuit.
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l3l33as
Referring next to I~'igs.~--lI`,a third embodiment of the
present invention will be described in comparis on with tlle second
mbodiment.
the /
In the cnse of/teacllin~ step with a teaching device
359 and in the case of the grinding step accomplished in accordance
witll the data o grinding paths stored in the teaching step, the
detection of an overload acting on a grindstone 2;42 will be des-
cribecl. As hest shown in Fig.6, a first pair of overload sensors
361 and 362 sucll as magnetic sensors are disposed at the upper and
lower stroke ends,respectively,of a piStOII 245 in opposing relationsllip
witll each other withill a first air cylinder 244. In the case o f
grinding tlle surface to be grolmd 104 in the ~- and Y-directions,
when an overload occurs,tlle upper or lower sensor 361 or 362
generates a detection signal in response to an abnormal approach
oE the piston 245 to the upper or lower sensor 361 or 362. In
case of grinding the surface to be ground 102 in the Y- and Z-
directions or the surface to ~e ground 103 in the ~- and Z-directions,
the upper overload sensor 361 detects the uppermost strolce position
of the piston 245 ( at which tlle grindstone 242 is located its
lowermost position),thereby determining the normal position of the
grindstone 247.
As shown in Fig. 7,a second pair of overload ~ensors 363
and 364 are dispose(l at the uppermost and lowermost stroke ends,
respectively,of a piston 250 in opposing relationship with each
other in the second air cylincler 247.When an overload acts on
the grindstone 242 in the lateral direction or longitudinal direction
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in case oi- grinding the surfaces to be ground 102 and 103,
tlle overload sensors 363 and 364 deliver the detection signal
in response to an abnormal approach of the piston 250 to the
left or right sensor 363 or 364. In case of grinding the
surface to be groulld 103, the le~t sensor 363 shown in Fig. 7
detects the piston 250 displaced to ltS leftmost position ( at
which the supporting arm 236 is maintained in a vertical position),
thereby determining the normal position of the grinclstone 242.
Furthermore,a fourth overload sensor 366 such as a
magnetic sensor is disposed in a supporting member 254. ~len
an overload which forces the supporting arm 236 to rotate in
the clockwise direction in Fig. 7 in the case of grinding the
surface 104 to be ~ro~md,the overload sensor 366 generates a
detection signal in response to an abnorrnal compression of the
stop spring 253 in the supporting melllber'254.
Referring bacl; to Fig.6 again,a third overload sensor
365 such as a magnetic sensor is disposed on the outer surface
of an air motor 23~. I~en an overload acts on the grindstone 242
in such a manner tllat the grindstone 242 is forced to rotate
abouth a pivot pin 239,the overload sensor 365 generates an overload
detection signal in response to an abnor~al approach to the
supporting arm 236.
Xeferring next to Fig.9, the arragement of switches
on a control panel 357 will be described. A mode selection switch
371 for selecting the manual operation mode,the teaching mode or
tlle grinding mode is disposed at the upper left portion of the
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control panel 357 an(l display lamps 372a,372h and 372c are located
at the mode selection positions,respectively,of the selection
switch 371. A direction selection switch 373 for selecting the
directions in whicll a grin(lstone head2,19 is displaced is located
below the mode selection swticll 371 and display lamps 374a,374b
and 374c are disposed at the selected direction positions,respectively,
of the direction selection switch 373. That is, the display lamp
374a,374b or 374c is turned on in response to the selection of the
Y- and Z-directions ,the ~- and '~-directions or the X- and Z-directions.
A teaching-mode operation region 375 is allocated at the
center portion of the control panel 357. A display lamp 376 which
is turned on when the mode selection switch 371 has selected the
teaching mode is disposed at the upper portion of the region 375.
A velocity selection switch 377 for selecting a velocity of dis-
placement of the grindstone head 219 in the teaching mode or step
is located wi~in the operation region 375. Display lamps 37~a,
378b and 378c co~espon~n~ to the low,medium and high velocities,
respectively, are disposed a~ the positions,respectively,of the
velocity selection switch 377 within the operation region 375.
A display device 379 for displaying a remaining period of time
during which the grincling operation can be further stored in the
teaching mode or step is disposed below the velocity selection
switch 377. A start switch 380 for starting the teaching mode or
step and an end switch 3~1 for interrupting the teaching mode of
step are disposed on the left side of the operation region 375.
~3R2J
An operation-mode operation region-Y~s allocated at the
1 3 1 3308
ri~t portion of tlle control panel 357. A display lamp 383 which is
turned on wllen the mode selection switcll 371 has selected the
grinding mode is disposed at the llpper portion of the region 382.
A processing time indicator 384 for previously setting the whole
grinding time and a time display device 385 for displaying the
remaining time in the grinding mode or step are disposed at the
right side within the operation region 382. A start switch 386
for starting the grinding mode or step and an end switch 3S7 for
interrupting the ~rinding mode or step are disposed on the left
side withirl the operation region 382.
Referring next to Fig. lo,the construction of the teaching
device 359 will be described below. An operation handle 391 is
extended fowardly from tlle right side of the front surface of
the teaching device 359 in such a way that it can be inclined and
rotated in a desired direction from the top to the left side as
indicatec by the arrows marked on the front surface of the teaching
device 359. A pair of direction display lamps 392 and 393 and
another pair of direction display lamps 39~ and 395 are disposed
at the upper and left portions,respectively, on the front surface
of the teaching device 359. ~len the Y- and Z-directions in which
the grindstone head 219 is displaced are se].ected by the direction
selection switch 373 on the control panel 357,the display lamps
392 and 395 are turned on;when the ~- and Y-directions are
selected,the display lamps 393 and 394 are turned on;and when the
X- and Z-directions are selected,the display lamps 393 and 395
are turned on,thereby indicating the operation direction of the
__ ,
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1 31 3308
o p e Là t i o n handle 391.
A pair of encoders 396 and 3~7 are disposed incorres~ondance
witll the operation handle 391 within the teaching
device 359 and are adapted to be activated through rotating
shafts and the like in response to the horizontal inclination
and rotation of the operation landle 391 so as to generate the
output signals for energizing the X-,Y~ and Z-direction motors
208,213 and 220 in response to the direction of rotation and the
angle o rotation. In addition,a start switch 39~ for starting
the teaching mode or step and a switch 399 for decelerating the
displacement velocity of the grindstone head 219 are disposed on
the front surface of the teaching device 359.
~ eferring next to Fig.lL, the control circuit of the
grinding machine with the above-described construction will be
e~plained. A central processing unit CPU 401 is connected to a
read-only memory (RO~I) 402 and a random access memory ~R~) 403
~hich constitutes a storage means. A program for controlling all
the operations to be accomplished by the grinding machine is
stored in ROM 402 while the data of grinding paths to be followed
by the grindstone head 219 derived from the teaching device 359 in
the teaching mode or step is stored in ~ 403.
The group 404 of switches on the control panel 357,
the teaching device 359 and the group of overload sensors 361-365
are connected through an input interface 406 to CPU 401. In addition,
CPU 401 is connected through an output interface 408 to the X-
direction motor 208,the Y-direction motor 213,the Z-direction motor 220,
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the air motor 238 and a display lamp group 407 consisting of the
above-described display lamps on the control panel 357 and the
teaching device 359 through driving circuits 409-413,respectively,
so that the driving and stop signals can be trasmitted to them.
NeY.t the ~lode of operation of the grinding machine with
the above-described construction will be explained.
As shown in Figs.4 and 5,the workpiece 101 such as a
die is mounted on the table 225,brought to and maintained at the
operation position immediately below the grindstone head 219.
In case of the teaching mode or step in which the grinding
paths are taught by displacing the grindstone head 219 along the
surfaces to be ground 102,103 and 104,first the teaching mode
is selected by the mode selection switch 371 on the control
panel 357 and then two directions ( for instance,the X- and Y-
directons) in which the grindstone head 219 is displaced are
selected by the direction selection switch 373.Next the displacement
velocity of the grindstone head 219 is set to a desired value such
as the medium displacement velocity by the velocity selection
switch 377 in the teaching operation region 375. Then,the remaining
time display device 379 displays the remaining time during which
the data can be stored in RA~I 403 while the display lamps 393 and
394 on the teaching device 359 Are turned on to indicate the
direction in which the operation handle 391 is operated.
Thereafter,in accordance with the display lamps 393 and
394 which are turned on,the operation handle 391 is leveled and
rotated in the X-direction,the Y-direction or in the direction
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between them. Tllen in response to the direction of rotation and
the angle of rotation of the operation handle 391, the encoders 396
and 397 deliver the detection signals to CPU 401 which in turn
delivers the driving signals to the .~- and Y-direction motors
208 and 213 to ener~ize them. Upon energization o the motors
20S and 213,the grindstone head 21~ is displaced by a predetermined
distance in the Y- and Y-directions. Concurrently,the same signals
are delivered from CPU 401 to Pl~l 403 so that only the position
data is stored as the data of grinding paths regardless of the
tracing velocity. Thus,when the operation handle 391 is leveled
and rotated while confirming the position to which is displaced
the grindstone head 219, the data o~ grinding paths in the X-
and Y-directions along the bottom surface 104 to be ground of
the workpiece 101 can be easily stored.
Next in case of grinding the bottom surface 104 to be
ground of the workpiece 101 based on the data of grinding paths
thus stored, the operation or grinding mode is selected by the
mode selection switch 371 on the control panel 357 and the whole
grinding operation time is set by the time setting device 384 in
the operation region 382. I~hen the start switch 386 is depressed
under these conditions,the remaining period of time for the grinding
operation step is displayed while CPU 401 reads out the data of
grinding paths from R~ 403 so that in response to the data thus
read out,the driving signals are delivered to the ~'- and Y-direction
motors 208 and 213. As a result,both the motors 208 and 213 are
energi~ed so that the grindstone head 219 is displaced in the ~-
1313308
and Y-directions.
In this case, the first air cylinder 244 as shown in
Fig.6 forcibly presses tlle grindstone 242 against the bottom
surface 104 to be ground of the worlcpiece 101 while the air motor
~38 causes the grindstone 242 to reciprocate. As a result,the
surface 104 to be ground is ground successively along the pre-
determined grinding paths.The grinding operation is repeatedly
carried out as the grindstone head 219 reciprocates in accordance
with the data of grinding paths until a previously set period of
time set by the time setting device 3~4 has elapsed. Therefore,
it is not needed to indicate a grinding path for each stroke
of the grindstone head 219 so that the grinding process can be
carried out efficiently.
In this embodiment,during the first displace~ent of the
grindstone head 219 in the grinding step,the grindstone head 219
traces the return path from the end position to the start position
of the displacement of the grindstone head 219 determined in the
teaching mode or step so that it is not needed to return the
grindstone head 219 from the end position to the starting position
of the displacement thereof after the completion of the teaching
step or mode and consequently the grinding process can be much
simplified. In addition, the grindstone ~2 can be positively
prevented from colliding against the projections or the like on
the surface to be ground which tends to occur when the grindstone
head 219 is linearly returned from the end position to the starting
position of the displacement thereof.
13t3308
Furthermore,in case of grinding the left or right
side surface 102 or the front or rear surface 104 of the workpiece
101, the grinding path data is inputted after the two directions
such as the Y- and Z-directions or Y~- and Z-directions are selected
by the direction selection switcll 373 in the teaching mode or step.
Then, according to the data of grinding paths thus obtained,the
grindstone 242 can easily and efficiently grind the right and left
surfaces to be ground 102 and the front and rear surfaces to be
ground lQ3.
I~len the grindstone 242 collides against a projection
or the like on the surface to be ground in case of the teaching
or grinding step so that an overload acts on the grindstone 242,
one of the overload sensors 361-366 as shown in Figs 6 and 7
delivers the detection signal to CPU 401 which in turn delivers
the stop signals to the ,~-,Y- and Z-direction motors 20~,213 and
220 and the air motor 338 so that the displacement of the grindstone
head 2;19 and the grinding operation by the grindstone 242 can be
immediately interrupted. In addition,an "erase data " signal
is delivered from CYU 401 to R~ 403 so that the grinding path
data stored in R~I 403 is erased Therefore,there is no danger
that the grinding operation is continued by the overloaded grindstone
242 or the repetition of the grinding operation in accordance with
the erroneous data of grinding paths can be avoided. Thus,the
grinding process can be safely accomplished.
In the third embodiment,the reciprocal movement in the
grinding step can be determined by a predetermined times of rotations
-33-
1 31 33~8
instead of the determination by a preset period of time described
above.
~ eferring ne~t to Figs.12 and13 , a fourth embodiment of
the present invention or a die polishing machine embodying the
present invention will be described.
The frame of the die polishing machine is equipped with
a supporting cylinder 501 movable in the ,~-,Y- and Z-directions
and a mounting shaft 502 is securely attached to the lower end of
the supporting cylinder 501. A head bloclc 503 is carried by the
mounting shaft 502 in such a way that the rotation about the
vertical axis of the head bloclc 503 is adjustable and is normally
securely held in a predetermined position by means of a clamping
lever 504. A bracket 506 is rotatably carried by the head block
503 through a horizontal shaft 505 in such a way that it can be
brought to a desired angular position through a worm 508 and a
worm wheel 509 by a handwheel 507 and is normally securely held
at a desired position by means of a clamping lever 510. The head
block 503 and the bracket 506 constitute a grindstone head 511
of the die polishing machine.
A rail 513 is disposed within the bracket 506 and slidably
supports an air cylinder 516,which is biasing means,through a
slider 515. The upper end of the piston rod 517 of the air
cylinder 516 is securely joined to a guide member 514. A mounting
~ember 519 formed with a plurality of mounting holes 518 is securely
mounted on tl~e air cylinder 516. An air motor 522,which is driving
means, is supported by the mounting member 519 by bolts 520 inserted
. -34-
1 31 330~
through the selected mounting holes 518 ln such a way
that the position of the air motor 522 can be
changed. A swinging member 524 is connected through
an oscillation generator 523 to the air motor 522. A
grindstone 526 is attached with a clamping screw 525
to the lower end of the swinging member 524 in such a
way that the angle of inclination of the grindstone
525 can be adjusted.
In case of grinding the surface of an
impression or cavity in a die 101 by the die polish-
ing machine with the above-described construction,
first the angular positions of the head block 503 and
the bracket 506 of the grindstone head generally
indicated by the reference numeral 511 are suitably
adjusted so that the grindstone 526 is brought to a
position in opposing relationship with a desired
surface to be ground of the work 101. For instance,
the head supporting cylinder 501 is so controlled to
be fed in the X- and Y-directions, the grindstone
head 511 is positioned as shown in Fig. 12 so that
the grindstone 526 is located in opposing relation-
ship with the bottom surface of the die 101. When
the head supporting cylinder 501 is so controlled as
to be fed in the Y- and Z-directions and when the
bracket 506 is rotated in the counterclockwise
direction to a position anyularly spaced apart the
position shown in Fig. 12 through 90. Then the
grindstone 526 is in opposing relationship with one
of the side surfaces of the work 101. When the head
block 503 is rotated through
~'
~ . .
1313308
90 about the vertical a~is under these conditions,the grindstone
526 is brought to a position in opposing relationship with the
other side surface of the worlc 101 SO that the grindstone 526 can
be fed in the ~- and Z-directions.
When the air cylinder 516 is energized after the grindstone
526 has been brought to a position in opposing relationship to the
desired surface to be ground,in response to the displacement of
the main body of the air cylinder 516,the grindstone 526 is
pressed against the surface to be ground. The pressure applied
to the grindstone 526 can be suitably adjusted by adjusting the
working pressure applied to the air cylinder 516. ~len the air
motor 522 is energized under these conditions,the grindstone 526
is oscillated by the oscillation generator 523 and grinds the
surface to be ground. In this case,the air cylinder 516 normally
presses the grindstone 526 against the surface to be ground so
that it is displaced following the variations in shape of the
surface to be ground. Therefore,the surface to be polished can
be polished uniformly with a high d~gree of precision without
causing the insufficient polishing of the recessed portions of
the surface to be polished and the excessive polishing of the
projected portions thereof. Furthermore,since the air cylinder
516 is disposed on the side of the grindstone 526 rather than on
the side of the grindstone head 511,the vibrations of the air
motor 522,the oscillation generator 523 and the grindstone 526
are damped by the air cylinder 516 so that the vibrations transmitted
to the frame can be reduced to a miminum.
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1313308
Fig.l3 sllows another applica~ion of the fotlrth embodiment
o the present invention.An arm member 52~ is interposed bet~Jeen
the grindstone llead 511 and the air cylinder 516 so that the ~rindstone
526 can be located at the deep portion of the wor}cpiece 101.
rlhnt is,a supporting arm 529 is securely attached to the
heacl block 503 o~ the grindstone head 511 and tlle base end of the
arm member 523 is pivotably attached ~ith a pivot pin 530 to the
supporting member 529. A link 531 is interconnected between the
midpoint bet~leen the ends of the arm member 52~ and the mounting
hole 518 of the mounting member 519. In aclditionJ the air motor 522
having the grindstone 526 is removed from the mounting member 51~
and is mounted at the lower end of the arm member 528 with a screw
532. The force of the air cylinder 516 is transmitted through the
link 531 and the arm mem~er 528 to the grinstone526 so that the
latter is pressed against the surface to be ground or polished
of the workpiece 101 under the force depending upon the working
pressure supplied to the air cylinder 516. Tllerefore, the grindstone
526 can reach even the deepest portion of the workpiece 101 without
being interrupted by the grindstone head 511 and the guide member
514 so that even the detailed portions of the surface having a
complicated pattern of the workpiece 101 can be easily ground.
In the fourth embodiment,instead of the air cylinder 516
a bias spring may be used and the grindstone 526 may be directly
connecred to the air motor 522 so that the surface to be ground
may be ground by the rotation of the grindstone 526.
Referring next to Fig.l4,a fifth embodiment o the present
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1 31 3308
invention or a die l~olislling machine emboclying tlle present invention
will be describe(l.
A frame ~generally indieated by the reference numeral 601
has a gantry-lil;e constrttction having rl pair of telescopic columns
S02 and a cross girder S03 and a table 604 on whicll is mounted a
~orkpiece 101 movably ride~ on a pair of rails 605 laid through
the die polishing or grincling machine. An ~'-directon moving body
607 ~hich is driven by an ~-direction motor 606 is mounted on the
cross girder 603 and a Y-direction moving body 609 which is driven
by a Y-direction motor 60~ is mounted at the lower portion of the
~'-direetion moving body 607. A Z-direction lead screw 611 is extended
downwardly througll a guide eylinder 610 seeurely mounted on the
Y-direetion,moving body 609 and is driven by a Z-direetion motor
612 so that the lead screw 611 is vertieally moved.
A grindstone head 613 is mounted at the lower end of
the Z-direction lead serew or shaft 611 in sueh a way that the
angular position in a horizontal plane of the grindstone head 631
ean be adjusted. A braeket 615 is pivoted with a horizontal pivot
pin 614 tc) the grindstone head 613 in sueh a way that its angular
position in a vertieal ~lane ean be adjustecl. An air eylinder 617
is movably mounted on a guide member 616 seeurely attached to the
braeket 615 and its piston rod 61~ is seeurely joined to the guide
member 616. An air motor 619,which is driving means,seeurely mountecl
through a mounting meTnber 622 on the air cylinder 617 and is drivingly
eoupled through an oseillation generator 620 to a swinging member 621.
A grindstone 624 is connected to the swin~ing member 621 with a
3~-
1 31 3308
screw 623 in such a way that the angular position of tlle ~rindstone
624 can be adjusted. l`he grinclstone 624 is pressed against the
surface to be ground of the worlcpiece 101 under the force of the
air cylinder 617. I~hen the air motor 619 is energized under these
conditions, the grindstone 624 is forced to slide through the oscillation
generator 620,thereby grinding the surfaces of an impression or cavity
in the workpiece lOl.
In the fifth embodiment,the braclcet 615,the guide member
616 and the mounting member 622 constitute a mounting assembly.
Therefore the grindstone 624 grinds the surface to be ground of
the workpiece 101 at an eccentric position with respect to the
axis o~ the lead screw or shaft 611 supporting the grindstone
head 613. As a result,even ~hen the Z-direction lead screw or
shaft 611 is extended longer do~nwardly,the vibrations caused
by the rotation of the air motor 619 and the sliding motion of
the grindstone 624 can be damped by a plurality of component
parts interposed between the grindstone 624 and the grindstone
head 613 so that impacts actlng on the moving bodies 607 and 609
and the frame 601 can be reduced to a minimum.Furthermore,since
the position of the grindstone 624 is spaced apart from the extension
of the axis of the Z-direction lead screw or shaft 611 in the
horizontal direction by a suitable distance,there exists no danger
that a very great oscillation momement due to the single harmonic
motion acts on the side of the frame 601. Therefore,the constructions
of the moving bodies 607 and 609 and the frame 601 can be simplified.
In the fifth embodiment,the component parts of the mounting
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assembly can be suitably increased or decreased in number. Furthermore,
the grindstone 624 can be directly connected to the alr motor 619
so that the surface to be ground is ground by the rotation of the
grindstone 624. In addition,the air motor 619 may be mounted on
the frame 601 and be drivingly coupled to the oscillation generator
620 through a suita~le power tansmission mechanism using a wire
so that the surface to be ground is ground.
Referring next to Figs.15-18,a sixth embodiment of the
present invention will be described.
As best shown in Fig.17,a grinding tool 723 is detachably
mounted at the leading end of a driving shaft 722 of an air motor 721
and is pressed against the surface to be ground of a wor~piece 101
by an air cylinder 71~.
As shown in Fig.15,a ball member 725 is formed integ~ally
with the leading end of a mounting shaft 724 of the grinding tool
723 and a pair of engaging projections 726 whose axes are per-
pendicular to the axis of the mounting shaft 724 are extended
radially outwardly from the center portion of the ball member 725
in a symmetric relationship with each other with resect to the
center of the ball member 725 in order to transmit the rotation.
A socket 72~ for receiving therein the ball member 725
is formed on the upper surface of a mounting member 727 of the
grinding tool 723. The socket 72~ is formed with a pair of engaging
grooves 729 in diametrically opposing relationship with each other.
The engaging projections 726 are slida~ly fitted into and guided
by tlle engaging grooves 729,respectively. The inner bottom of the
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1 3 1 3308
soc1;et 72~ is formed with a supporting recess 730 extended downwardly
toward the lower surface of the mounting member 727. The supporting
recess 730 is made intocon~act with a portion of the spherical
surface of the ball memher 725 so that the relative rotation
between the ball member 725 and the supporting recess730 is permitted
in the direction in which is inclined the mounting shaft 724.
A flat circular rubber cushion member 731 is securely
joined to the undersurface of the mounting member 727 and an abrasive
stone 732 consisting of a sheet of diamond paper is securely joined
to the undersurface of the cushion member 731. The abrasive stone
732 consists of a cloth base 733 and a plurality of partially
helical abrasive layers 734 consisting of bonded synthetic diamond
abrasive grains. ~ach abrasive layer 734 is formed witll a discharge
surface 734a for discharging the dislodged grains and chips which
is curve~ backwardly with respect to the direction of rotation
of the grindstone.
I~en the air motor 721 is energiæed while the grindstone
732 is made into contact with a surface to be ground, the grind
stone 732 is made into intimate contact with a wide contact portion
of the forming surface of the workpiece 101 regardless of its
pattern withollt leaving any non-contact portion and is rotated.
Therefore,the grinding efficiency is improved and the chips are
discharged along the discharge surfaces 734a when the grindstone
732 is rotated. In addition,the abrasive stone 732 can be rotated
between the position indicated by the solid lines and the position
indicated by the two~dot chain lines as shown in Fig.15 ,following
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the projections and recesses of the surface to be ground of the
workpiece 101 so t~lat the grinding operation can be carried out
smoothly and that it is not needed to change the angle of inclination
of the mounting shaft 724.
Because of the provision of the bracket 716,the guide
member 717 and the mounting member 7ZO,the grindstone 732 grinds
the surface to be ground of the workpiece 101 at a position eccentric
to the a~is of the grindstone head 714 and the Z~direction lead
screw or shaft 712. Therefore even when the Z-direction lead screw
or shaft is extended longer downwardly,vibrations caused by the
rotation of the air motor and the grinding tool 723 in the grinding
operation are damped by a plurality of component parts interposed
between the grindstone 732 and the grindstone head 714. As a
result,impacts which act on the moving bodies 707 and 709 and
the frame 702 can be reduced to a minimum.
In the grinding tool 723 of the sixth embodiment,the
leading end of the mounting shaft 727 is terminated into the ball
member 725 and the mounting member 727 on whicll is mounted the
grindstone 732 such as diamond paper is provied with tlle socket 728
for receiving tllerein the ball member 725. The inner bottom surface
of the socket 728 is formed with the supporting recess 730 which
is made into contact with a portion of the spherical surface of
the ball member 725 to support the same. Therefore,the supporting
recess 730 upon which acts the pressing force so as to press the
grindstone 732 against the forming surface of the workpiece 101
can be formed in close pro~imity of the grindstone 732.As a result.
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the force for causing the grindstone 732 to move away from the
surface being ground oi the worl;piece 101 ~hich is caused when
the axis of tlle mounting shaft 724 intersects that of the mounting
member 727 and the centrifugal force procluced upon rotation of
the mounting member 727 can be reduced to a miminum. Consequently,
the movement oE tlle grindstone 732 away from the surface to be
ground of the workpiece 101 can be almost prevented so that the
ability of the grindstone 732 to follow the pattern of the surface
to be ground of the wor~piece 101 is improved and therefore the
smooth grinding operation can be ensured.
In the grinding tool 723 of the sixth embodiment,the
distance between the supporting recess 730 of the mounting member
727 and the grindstone 727 is shortened so that the diameter of
the mounting member 732 can be decreased correspondingly. Therefore,
the grindstone 732 can easily follow the projections and recesses
each having a small curvature of radius of the surface to be ground of
the workpiece lOl so that the uniform grinding operation can be
ensured.
In addition,as compared with the relatedart grinding tools,
the grinding tool 723 of the sixth embodiment has a less number of
component parts and therefore is simplified in construction and
asse~bly.
T~e sixth embodiment described abvoe can be modified as
follows:
(1) As best shown in Fig.l~,the cushion member 731 can be eliminated
and the mounting member 727 is made in the form of a flat plate.
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And the ~rindstone 732 is directly joined to the undersurface
of the flat-plate-lilce mountin~ member 727.
(2) The air mo~or 721 can be mounted,for instance,on the frame 702
so as to drive tlle driving shaft 722 through a power transmission
mechaism using a wire,thereby grinding the surface to be ground.
(3) The grindstone 732 can be made in the form of a flat plate.
(4) The grinding layer 734 of the grindstone 732 can be arranged
ill the form of a spiral in a flat plane.
(5) The mounting member 727 and the socket 728 can be made of a
hard synthetic resin and anti-abrasion sheet metal can be disposed
in the engaging grooves 729 and the supporting recess 730,whereby
the grinding tool can be made light in weight.
Y~eferrîng neY~t to Figs.19-25,a seventh embodiment of the
present invention will be described below.
As shown in Figs.l9 and 21,a grindstone head 814 consisting
of a head block 815 and a bracket 816 is attached through a rotary
mechanism 817 to the lower end of a shaft 812 which can be displaced
in the Z-direction ( to be referred to as " the Z-direction shaft "
for brevity hereinafter in this specification).The grindstone head
814 i5 rotatable about the axis of the Z-direction shaft 812 in
unison with the rotary mechanism 817.The rotary mechanism 817 is
composed of a servomotor 819 mounted on one side of a casing
818,a worm 821 securely carried by an output shaft 820 of the servomotor
819 and a worm wheel 823 carried by a supporting rod 822 extended
downwardly from the lower end of the Z-direction shaft 812. The
rotary mechanism 817 can be rotated from its initial position
indicated in Fig.19 through 360 in both the clockwise and counter-
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clocwise directions. As best shown in Fig.21 ,a rotary encoder 824
for detecting the angle of rotation of the output shaft 820 is
mounted on the casing 818. The head block 815 is disposed in such
a way that its angular position in a horizontal plane can be
adjusted with respect to the rotary mechanism 817.
As shown in Fig. 21,the bracket ol6 has a pair of supporting
plates 816a and 816b between which is clamped the head block 815
and is rotatable about a horizontal shaft 825 in such a way that
its angular position in a vertical plane can be adjusted suitably.
The bracket 816 is securely held in a desired position by means of
a clamping lever 827 which is extended through an elongated hole
826 formed through the supporting plate 816a and is made into
threadable engagement with the head block ~815. A guide member 828
with a rail 829 is securely attached to the bracket 816. A first
air cylinder 831 is movably supported through a slider 830 by
the rail 82~ and its piston rod 832 is securely connected to the
guide member 828. An air motor 835,which is a driving means, is
colmected through a ~olt 834 to a mounting member 833 which in turn
is securely attached to the air cylinder 831. A grindstone 838 is
rotatably attached through a mounting sha~t 837 to the driving shaft 836
of the air motor 835.
The grindstone 838 may be swingably connected through
an oscillation generator 853 or 854 as shown in Fig.23 or 24~
respectively,to the air motor 835. In this case,the grindstone
838 is used to cut longitudinal grooves in order to facilitate
to finish the surface to be ground of a forming die and to
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draw a formed product out of the die.
As shown in Figs.19 and 21, a mounting plate 839 is disposed
on the other supporting plate 816b of the bracket 816 and is made into
intimate contact therewith in such a way that it is rotatable about
the horizontal shaft 825 and its angular position can be adjusted.
~he mounting plate 839 is securely held at a desired position by
the coaction between a spacer 842 and a clamping lever 840 which
is extended through an elongated hole 841 of the mounting plate 839
and is threadably engaged with the head block 815 when the clamping
lever 840 is rotated.
A supporting arm 843 is extended outwardly from the
outer side at the upper portion of the mounting member 839. A
second air cylinder S45 whicll rotates the bracket 816 so as to press
the grindstone 838 against the surface to be ground of the workpiece
lOl is rotatably supported by a shaft 846 between a pair of upright
bearing members ~44 e~tended upwardly from the upper surface of the
supporting arm 843. The leading end of the piston rod 847 of the
air cylinder 845 is pivotably connected through a connecting member
~48 to the guide member o28. The bracket 816 becomes rotatable
when tlle clamping lever 827 is loosened while the mounting plate
839 is securely held in position by the clamping lever 840. T~7hen
the second air cylinder 845 is energized so that its piston rod 847
is extended,the bracket 816 is rotated from the position indicated
by the solid lines to an inclined position indicated by the two-dot
chain lines in Fig. 19. Both of the cylinders 831, 845 are controlled by the
circuit as shown in Fig. 8.
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In case o~ grinding the surface 105 (in the
~orm of an ellipse as shown in Fig.22 ) of a vertical recess in a
workpiece lOl as shown in Fig.20 with the die grinding machine
with the above-described construction,the angular position of
the bracket ~16 of the abrasive stone head 814 is so adjusted
that the axis of the guide member ~2~ is perpendicular to the
axis of the Z-direction shaft &12. And the bracket ~16 is securely
held in position by the clamping lever ~27 so that the abrasive
stone 83~ is in opposed relationship with the surface to be ground
105 on the left side of the work 101. ~len the switch on the control
panel ~49 is actuated under tllese conditions,
the first air cylinder o31 is energized. As a
result,the grindstone ~3~ is pressed against the surface to be
ground 105 at a predetermined pressure by the first air cylinder
~31.
I~hen the air ~notor ~35 is energized Imder these conditions,
the grindstone ~3~ is rotated while the grindstone head ~14 is
moved upwardly anc~ do~m~ardly so that a portion of the curved
surface to be ground 105 is ground in a predetermined width in the
vertical direction.Thereafter the grindstone head ol4 is displaced
downwardly a~d rightwardly in Fig.22 and is slightly rotated
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stepwise by the servomotor 8l9 so that the surface to be ground
105 continuous with the ground surface ls ground successively. At
the corner portions shown in Fig.22, the grindstone head 814 is
rotated as indicated by the two-dot chain lines by the servomotor
819. Therefore the grindstone or abrasive stone 838 is disposed
`:~
in opposing relationship with the surface to be ground lOS so
that the cuFved surface to be ground 105 is contlnuously ground.
:` :
In the case of`;grinding the surface to be ground 106,
the clamping lever 827~is Loosened to permit the rotation of the
~ bracket 816 while the mounting plate 839 is securely clamped ~
- ~ by the clamping lever 840. When a switch on the control panel 849
is actuated under these conditions,
~ the
first ànd second air cylinders 831 and 845 are energized. Then
:~ .
- the bracket 816 is rotated and located at the inclined position
" ~: : ;
- ~ -48-
-: '
.
:`'
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as indicated by the two-dot chain lines in Fig.lg by the
second air cylinder 845 while the grinAstone 837 is displaced
along the bracket ~16 by the first air cylinder ~31. Thus,the
grindstone or abrasive stone 33~ is pressed against the surface
to be ground 105 under the combined force o~ both of the first and
second air cylinders 831 and 845 at a predetermined pressure.
~ len the air motor ~35 is energized under these conditions,
the grindstone $38 is rotated while the grindstone head ~14 is
displaced not only in the right and left directions but also in
the vertical direction. As a result,a predetermined width of a
portion or the surface to be ground 106 is ground. Thereafter
the grindstone head 814 is moved downward and rightwa~d:in Fig. 22
and the grindstone head 814 is rotated by the servomotor ~19. Therefore
the grindstone or abrasive stone ~3~ is positioned in opposing relationship
with the surface to be ground 106 so as to continuously grinde the
same.
In case of grinding a flat surface to be ground 107,
two directions;that is,the longitudinal direc~ion ( the forward and
baclcward directions) and the vertical direction are selected as the
directions in which rhe grindstone head 814 is displaced.Thereafter,
the bracket 816 is brought to the position indicated by the solid
lines in Fig.l9 and is securely held in position. Ne~t as in
case of grinding the surface 105,the first air cylinder 831 is energized
so that the abrasive stone 814 is displaced not only in the transverse
direction but also the longitudinal direction ( perpendicular to the
paper of Fig.21),thereby grinding the bottom surface 107.
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In case of grinding the surfaces to be ground of a
workpiece lOl as shown in Fig.23 with the die grinding machine
witll the above-described construction,first the clamping lever
827 is loosened to permit the rotation of the bracket 816. In
case of grinding tlle bottom surface to be ground 104 of the workpiece
101, two directions;that is,the transverse direction and the longitudinal
direction are selected by actuating a switch on the control panel
849 as the directions in which the abrasive stone head 814 is
displaced. Then
both the first and second air cylinders 831 and
845 are energized.Therefore the bracket 816 is rotated to the
position indicated by the solid lines in Fig.l9 by the second
air cylinder 845 while the abrasive stone 838 is displaced along
the bracket 816 in the downward direction by the first air cylinder
831 and is pressed against the surface to be ground 104 at a predetermined
pressure.
In this case, a small force is exerted from the second
air cylinder 845 to the surface to be ground 104 so that the guide
member 82$ tends to rotate in the countercloc~wise direction about
the horizontal shaft 825.
~ len the air motor 835 is energized under these conditions,
the abrasive stone 838 is rotated and when the ~- and Y-direction
motors 808 and 810 are energized,the abrasive stone head 814 is
arbitarily displaced in the transverse and longitudinal directions
so that the surface 104 is ground.
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~ lext in the case of grinding the right or left side
surface to be ground 102 of the workpiece 101,the longitudinal
and vertical directions are selected as the directions in which
tlle abrasive stone head 814 is displaced.Furthermore,the second
air cylinder 845 is energized so that the piston rod 847 is extended,
thereby rotating the guide member 828 to the position at which the
axis of the gulde member 828 becomes perpendicular to the axis of the
Z-direction shaft 812. Thereafter the first air cylinder 831 is
energized so that the grindstone 838 is pressed against the surface
to be ground 102 at a predetermined pressure. ~1hen the air motor
835 is energized under these conditions,the grindstone 838 is rotated
while the abrasive stone head 814 is arbitarily displaced in the
longitudinal and vertical directions in Fig.23 so that the abrasive
stone 838 grinds the surface 102 to be ground.
In case of grinding the foward or backward surface to be
ground 103 of the workpiece 101,the transverse and vertical directions
are selected as the directions in which the abrasive stone head 814
is displaced. The grindstone head 814 is then rotated through 90
from the position indicated in Fig. 23 and securely held in position
by the clamping lever 852. Thereafter the second air cylinder 845
is energized so that the piston rod 847 is extended to rotate the
guide member 828 to a pOSitiOII at which the axis of the guide member
828 becomes perpendicular to the axis of the Z-direction shaft 812.
Then the first air cylinder 831 forces the grindstone 838 to press
against the surface to be ground 102 at a predetermined pressure.
~en the air motor 835 is energized,the abrasive stone 838 is rotated
~ - ,
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while the grindstone head 814 is displaced in the transverse and
vertical directions in Fig.23 so that the abrasive stone o38 grinds
the surface 103.
In case of grinding the surfaces 108 merging between
the suri'aces to be ground 102,103 and 104 of the workpiece lOl,the
longitudinal and vertical directions in Fig.23 are seelected as
two directions in which the grindstone head 814 is displaced. Next
the second air cylinder 845 is energized so that the guide member
828 is rotated to the inclined position indicated by the two-dot
chain lines in Fig.l~. lhen the first and second air cylinders 831
and 845 coact to force the grindstone 838 to press against the
surface to be ground 108 at a predetermined pressure. I~hen the air
motor 835 is energi~ed,the grindstone 838 is rotated while the
piston rod o46 of the second air cylinder 845 is extended and
retracted. Concurrently,the abrasive stone head 814 is displaced
in the longitudinal and vertical directions so that the abrasive
stone 838 grinds the surface 108.
I~en all the surfaces of the work 101 have been ground
by the rotary abrasive stone 838,the air motor 835 and the abrasive
stone 838 are removed from the mounting member 833 and then the
att~t as shown in Fig.24 or 25 is attached to the attachment
member 833 so that the abrasive stone 838 is forced to oscillate
to finish the surfaces to be ground 102,103,104 and 108 and cut
logitudinal ~grooves therein.
In the seventh embodiment,the first and second air cylinders
831 and 845 coact to force the grindstone 838 to normally press
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against the surEace to be ground of the workpiece 101 at a predetermined
pressure. Therefore,the ~rindstone ~38 can be displaced smoothly,
following the variations in shape of the surface to be ground.
As a result,the grindstone $38 can grind the surface to be grolmd
uniformly and with a high degree of accuracy without causing the
non-uniform grinding such as the insufficient grinding of the
recessed portions and the excessive grinding of the projected
portions on the surface to be ground.Furthermore,the non-uniform
contact of the abrasive stone 848 with the surface to be ground
can be avoided.
In the seventh embodiment,the rotary mechanism 817
which rotates the abrasive stone head 814 about the axis of the
Z-direction shaft 812 can be rotated in unison with the abrasive
stone head ~14 so that the interference between the second air
cylinder 845 and the rotary mechanism 817 due to the rotation
of tlle head block 815 can be avoided.
In the senventh embodiment,the grinding of tlle surfaces
to be ground 105 and 107 of the workpiece 101 can be accomplished
while the bracket ~16 is maintained in the rotatable s~ate as
in the case of grinding the surface 106.
As described above,according to the seventh embodiment
of the present invention,the abrasive stone head can rotate about
the axis of the Z-direction shaft through the rotary mechanism so that
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in the cases of grinding a pluraity of vertically ex.tended surfaces
to be ground of a workpiece,the operation for changing the attachment
state of t~e grindstone with respect to the abrasive stone head by
an operator can be eliminated and consequently the efficiency of
the grinding operation can be improved. Especially,the seventh
embodiment has an excellent feature that it can grind uniformly
and with a high degree of accuracy a plurality of curved surfaces
to be ground which merge with each other.
ile~t referring to Figs.26-28,an eighth embodiment of the
present invention will be described.
As shown in Fig. 26,an X-direction moving body 902 is
mounted on a frame 901 of a die polishing machine and is displaced
in the transversedirection ~ the right and left directions) by
an X-direction driving motor 903. A Y~direction moving body 904
is mounted on the X-direction moving body 902 and is displaced
in the longitudinal direction ( forward and backward directions)
by an Y-direction motor 905. A Z-direction moving body 906 is
mounted on the Y-direction moving body 904and displaced vertically
by a Z-direction driving motor 907 and an abrasive stone 909 is
attached througll an abrasive-stone driving motor 908 to the lower
end of the Z-direction moving body 906. Upon rotation of the
driving motor 908,the abrasive stone 909 is forced to oscillate
or rotate,thereby grinding selectively an ~-Y surface to be ground
911,an XZ surface to be ground 912 and a Y-Z surface to be ground
913 of a forming di,e 910.
A control panel 914 mounted on the frame 901 is connected
_54_
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through a cable 915 to a portable remote-controlled teaclling
device 916. The teachig device 916 i5 provided with an operation
or joy stick 917 whicll can be inclined and rotated through 360.
The direction of inclination and the angle of inclination of the
operation or joy stick 917 are detected by a combined signal
from a first and a second shaft encoders 918 and 919 incorporated
in the teaching device 916 ( See Fig.28). The teaching device 916
is further provided with an input plate 920 and a correction
switch 921 which is a correction means activated when the abrasive
stone 909 follows an erroneous grinding path.
As shown in Fig.28,the input plate 920 is provided with
a mode selection switch 922 ~or selecting the manual operation
mode,the teaching mode or the playback mode,a surface selection
switch 923 for selecting the X-Y surface 911,the ,Y-Z surface 912
or the Y-Z surface 913,a start switch 924 for starting the teaching
or playback mode,an end switch 925 for interrupting each mode and
a di~play device (not shown) for indicating a selected surface to be
ground or polished.
These switches 921-925 and the encoders 910 and 919 are
connected to the input side of a central processing unit CPU 926
incorporated in the teaching device 916 and the display device
is connected to the output side thereof. The output terminal
of CPU g26 is connected to a CPU 927 incorporated in the control
panel 914 and the data signal is transmitted between
CPUs 926 and 927.
Referring still to Fig.28, the control panel 914 is provided
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with a start switch 924A for starting the teaching or playbacl;
mode, an end SWitClI 925A for interrupting each mode and a display
device (not sllown) ~or displaying various operation steps sucII as
the teaclIi2lg mode.
The switches 924A and 925A are connected to the input
side of CPU g27 and the xr- ~ Y- and Z-direction motors 903,905 and
907 and the abrasive-stone driving motor 90~ are connected to the
outoput side of CPU 927 and the drive and stop signals are transmitted
from CPIJ 927 to these motors. Furthermore,CPU 927 is connected to
ROI~I 92~ which stores a program for controlling all steps carried
out by the die polishing machine and to R~l 929 for storing the
data o~ grinding paths of the abrasive stone 909 which can be
reprogrammed as often as desired.
l~ext the teaching mode of the die polishing machine
with the above-described construction will be described. First
in case of teaclling the grinding paths, tlle teaching mode is
selected by the mode selection switch 922 on the teaching device
916. Then,for instance,the X-Y surface to ~e ground 911 is selected
by the surface selection switch 923 so that the direction of the
displacement of the abrasive stone 909 is limited only in the Y~-
and Y-directions.
Thereafter,when the operating or joy stick 917 is
inclined in a desired direction,the detection signals representative
of the direction of inclination and the angle of inclination,respectively,
are delivered from the encoders 918 and 919 to CPU 926 and then
transmitted to CPU 927 which in turn delivers the drive signals to
~.
-56-
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the ~- and Y-direction motors 903 and 905,respectively. Upon
rotation of the motors 903 and 905,the abrasive stone 909 is
displaced along a desired grinding path in either the hr- or Y-
direction and this grinding path is stored in I~AM 929.
I~lhen the abrasive stone 309 is displaced along an erroneous
grinding path 109 as shown in Fig.27 and wllen the correction switch
921 is depressed when the abrasive stone 909 is at a point 110,
CPU 926 delivers the signal to CPU 927. Then CPU 927 reads out
the grinding path data stored in P~l 929 in the reversed direction
and delivers the reverse signals to the ,~- and Y-direction motors
903 and 905. Then,the abrasive stone 909 is automatically reversed
to a desired grinding path 112 along the erroneous grinding path
109 from the point 110. When the abrasive stone 909 is returned
to a point 111 on the desired grinding path 112,the correction
switch 921 is released. Then,CPU 927 specifies the data of the
return path from the pointl10 to the pointlll as an erroneous
data and then erases this erroneous data. Therefore,the abrasive
stone 909 can be returned to a point of a desired grinding path
from which the abrasive stone 909 has traced the erroneous grinding
path and then the teaching mode can be continued smoothly without
any interruption.
When the playback mode is selected by the mode selection
switch 922 after the teaching mode has been accomplished,in response
to the depression of the start switch 924,the data of the desired
grinding paths which has been stored in RA~I 929 in the teaching
mode is read out. In response to the read-out data,the ~- and Y-
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direction motors 903 and 905 are energi~ed so that the abrasive
stone 909 are displaced along the desired paths on the ~-Y surface
to be ground 911 for a predetermined number of times or a for
a predetermined length of time,whereby the die 910 is automatically
ground by the oscillation or rotation of the abrasive stone 909.
In the eigtll embodiment,a large number of input switches
921-925 can be easily connected to CPU 926 incorporated in the
teaching device 916. Furthermore, if ado~ted a serial transmission
of the data signal between CPU 926 and CPU 927 incorporated in
the control panel 914,the number of cables 915 can be decreased
so that the cables 915 can be made light in weight. As a result,
the remote-controllability of a large-sized die polishinig machine
can be especially improved. Instead of the teaching device 916,
it is possible to use a wireless controller.
Furthermore,the erasure of the erroneous grinding path
can be accomplished when the abrasive stone 909 is automatically
retruned along the erroneous grinding path 109 to the desired
gringing path 112.
As described above,according to the eigth embodiment of
the present invention,when the abrasive stone is displaced along
an erroneous grinding path,the data of such erroneous grinding
path can be erased in storage means so that it is not needed
to start the teaching mode again from the initial point. ~urthermore,
there are no dangers that the grinding time is wasted in the playback
mode and that the ground surEace is varied in surface roughness
due to the excessive grinding of the erroneous grinding path.In
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the case of the displacement of the abrasive stone along an
erroneous grinding path,it can be returned along the erroneous
grinding path to the desired grinding path by actuating the
correction means. Therefore the abrasive stone can be re-positioned
again at a point on a desired grinding path from which the abrasive
stone has been displaced along the erroneous grinding path and then
the teaching mode can be continued again smoothly from the returned
point without any interruption. ~oreover,the abrasive stone can be
automatically returned to the desired grinding path in response to
the actuation of the correction means so that the correction step
can be accomplished easily and quickly.
It will be appreciated by those skilled in the art that
variations,alternations and/ or modifications may be resotred to
without departing from the spirit of the present invention and
the present invention is not restricted to the above-described
embodiments and may be practiced otherwise than specifically
described within the scope of the following claims.
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