Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a ~etl~od and apparatus for
dressing a grinding surface particularly having the form of
a complex contour on a wheel of a two-axis grinding machine.
This is a division of cop ending Canadian Patent application
Serial No. 393,273, filed December 27, 1981.
Angular feed grinding machines are well known in the
art. US. Patent No. 4,205,488 is exemplary of an angular
feed grinding machine, Straight feed grinding machines are
also well known in the art. US. Patent No. 3,076,296
teaches a straight feed grinding machine.
According to one aspect of the present invention, there
is provided a method of dressing a complex contour onto a
grinding surface of at least one grinding wheel of a two-
axis grinding machine for grinding a workups. The method
includes the step of causing at least one dressing diamond
to traverse the grinding surface of the grinding wheel along
a firs axis parallel to the axis of rotation of the
workups while simultaneously causing movement of the
dressing diamond with respect to the grinding surface along
a second of the said axis. The method also includes the
step of employing a programmable controller to control the
traversing and the movement, to automatically dress a
couples contour onto the grinding surface.
The invention further resides in a two axis machine for
grinding a workups and including means to support the
workups, one grinding wheel which is position able for
grinding the workups, and at least a first dressing
diamond position able to engage and dress a grinding surface
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of the grinding wheel. Means is provided for moving the
dressing diamond to traverse the grinding surface of the
grinding wheel in a first direction along the z-axis of the
grinding wheel, and a programmable controller controls the
moving means to provide a simultaneous movement of the
grinding wheel with respect to the dressing diamond along
both the z-axis and the x-axis so as to dress a desired
complex contour into the grinding wheel.
According to another aspect of the invention there is
provided a machine for grinding a workups including a
base, a swivel table adjustable mounted on the base with a
driven work head disposed on the swivel table and a
foot stock disposed on the swivel table for use with the work
head to support the workups there between. A wheel head is
provided which has at least one independently driven
external grinding wheel mounted thereon and is angularly
position able to grind the grinding wheel into position for
grinding the workups. The machine has at least one
dressing diamond supported from the base.
GRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, reference
may be had to the preferred embodiment exemplary thereof
shown in the accompanying drawings in which:
Figure 1 is a front view of a grinding center of the
type which may incorporate the present invention.
Figure 2 is a plan view of a grinding machine
incorporating the present invention.
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Figure 3 is a right side view of the grinding machine.
Figure 4 is a section view taken in figure 2 along the
line IVY with some items deleted or shown schematically
for clarity:
. Figure 5 is a section view taken in Figure 4 along the
line VET
Figure 6 is a section view through the tail stock
showing the pair of dressing diamonds;
Figure 7 is a view similar to Figure 2 but with the
wheel head moved to a position for angle feed of the
grinding wheel;
Figure 8 is a section view through the head stock;
Figure 9 is a diagrammatic view of a grinding wheel
disposed perpendicular to the front of the grinding center
and in position for contour dressing by the pair of
dressing diamonds;
Figure 10 is similar to Figure 9 but for a grinding
wheel disposed at an angle to the front of the grinding
center; and,
Figure 11 is a diagrammatic view of a single dressing
diamond pivotal supported for movement to offset
positions.
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EAST IDEA FOR CRYING OUT TIRE INVENTION
erroneous no to the drawings, there is shown
a dual wheel grinding center 10 constructed according to
eye teaching of the resent invention. The disclosed
oval wheel automatic external grinding center 10 is
capable of both straight and angled wheel feed.
Programmable controller 12 which receives input
data through an input station 14 controls various functions
of grinding center 10. Grinding center 10 includes a base
16 on which is supported a swivel table 20 and a grinding
head assembly So. A fluid coolant system 120 is provided
for supplying coolant during operation of grinding center
10. when grinding center 10 is installed, three pads 18
support base 16 from a floor.
Swivel table 20 is mounted to base 10 for
adjustable positioning about an axis 21 defined by a pivot
connection. Graduated scale 22 is provided to indicate
the adjusted position of swivel table 20. Swivel table
20 is adjustable through a 20 range about a longitudinal
axis of base 16. A work head 24 and a spaced apart
foot stock 26 are supported on swivel table 20. Work head
24 and footsto~k 26 include centers 25 and 27 respectively
for supporting a warps there between. Work head 24
includes spindle dry motor 28 which through a belt drive
rotates a work driver plate 30 at speeds of 5Q to 1000
rum Work head 24 is supported from a work head support
plate 32 and is adjustable fastened by suitable means
thereto. Work head support 32 is secured to swivel table
20. The position of work head 24 relative to work plate
32 is manually adjustable about a pivot pin connection 34.
That is, work head 24 can manually be positioned relative
to work head plate 32 around pin connection 34. Gradual
lions are provided on either side of the zero reference
position of worked 24 to facilitate accurate positioning.
The position of work head plate 32 is adjustable long-
tudinally along swivel table 20. Thus, work head 24 can
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Jo used for swather choosing worry or between center work.
Toe worn head is a combination live and dead spindle
resign which permits supporting of the workups on dead
centers while driving the workups from the work driver
slate 30 through a drive dog and drive pin set-up, or
operation as a live spindle arrangement while either
housing the workups or having it clamped to a face
plate.
Work head motor 28, through a plurality of
bullets 40, drives a sheave 42~ Sheave I is supported . -:
by bearings from a portion of York head 24 which supports
rotor 28. Center 25, which is a $10 Journey, is rotatable
supported within this same portion of work head 24. Work
shover plate 30 is connected to rotate with sheave 42.
Foot stock 26 is spaced apart from work head 24
on swivel table 20. The position of foot stock 26, like
ok head 24, is manually adjustable longitudinally on
swivel table 20. Dressing diamonds 36 and 38, as can
best be seen in Fig. 8, are provided on foot stock 26.
Supported from base 16 to the rear of swivel
tubule I are a pair of longitudinally extending flat
carrier ways 52 and 54. Flat carrier ways 52, 54 support
sounding assembly 50 for longitudinal movement along base
I A Mobil carriage 5Ç is supported from flat ways I -
and 54 for sliding movement thrilling. Carriage 56 is
position able along ways 52, 54 through a preluded nut 58
and ball screw 60 arrangement. Nut 58 is fastened to
carriage 56. Ball screw 60 is rotatable by a carriage
drive motor 62. Operation of carriage drive motor 62
rotates ball screw 60 to position carriage 56 along ways
I and 54. An optical incremental encoder 64 is connected
to carriage drive motor 62 to be driven in unison with
ball screw 60 for providing an output which is indicative
of the position of carrier 56.
A carrier traverse guide is provided for guiding
the movement of carriage 56 along flat ways 52 and 54.
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Carriage guide 66 is engaged by sliding pads 68 and 70
which wire collected Jo carriage 5G As carriage 56
moves along ways 52 and So, pads 68 and 70 egg
carriage guide 66 to accurately position carriage 56.
Guide way 66 is accurately positioned toward the front
of the grinding machine 10, vertically beneath work head
I and foot stock 26. The disclosed means of guiding
carriage 56 minimizes effects of thermal and grinding load
distortion and permits flat ways 52 and 54 to be utilized
in place of the more conventional vie way and flat way
arrangement. - -
A pair of slide ways 72 and 75 are provided on
the top of carriage 56 and extend above and generally
orthogonal to carriage ways 52 and 54. Wheel slide 76
is supported from wheel slide ways 72 and 74. Wheel
slide 76 is movable back and forth on slide 72 and 74
relative to swivel table 20 by a reloaded nut 78 and
ball screw 80 arrangement. Slide 76 is guided from the
sides of way 72 for accurate alignment. Wheel slide drive
motor 82 is connected to rotate ball screw 80 to move
s ire 76 to the desired position. An optical incremental
encoder is mounted to servo motor 82 to be driven in
unison with ball screw 80 providing an output indicative
of the position of wheel slide 76.
feel head assembly I is supported by and
rotatable position able on wheel slide 76. Wheel head 84
is angularly position able relative to wheel slide 76 about
pivot connection 85. A pair of spaced apart grinding
wheels 86 and 88 are mounted on spindles 90 and 92 from
wheel head assembly 84. A pair of AC drive motors 94, 96
are mounted to rotate the associated grinding wheels
86, 88 by belt drives through spindles 90, 92. Wheel head
84 can be rotated to a desired position for putting either
grinding wheel 86 or 88 in position for performing a
desired grind. Appropriate hood arrangements 98 and 100
are provided for providing guards around grinding wheels
I
So and 58 respectively. Ball screws 60 and 80 can be
drivel either independently or simultaneously at independent
or related feed rates to provide complete two axis movement
for driven grinding wheels 86, 88. Programmable
microcomputer control 12 controls movement of grinding
wheels 86, 88 for grinding or dressing.
In the illustrated embodiment grinding wheel 86 is an
angle feed wheel head whereas grinding wheel 88 is formed as
a straight feed wheel head. Grinding center 10 can be used
as a straight plunge grinder or an angle wheel feed grinder
or use in a shoulder grinding, through simultaneous two-
axis positioning. Drive motors 94 and 96 are 7-l/2 ho AC
rotors which drive grinding wheels 86 and 88 at a speed of
approximately 8500 sfpm.
A coolant system 120 is provided having a tank with a
50 gallon capacity and a coolant flow rate of 35 gallons per
minute Flexible pipe 122 connects the coolant pump output
Jo the wheel head 84 for supplying coolant to the
appropriate grinding wheel. Coolant pipe 122 connects into
coolant pipes 123, 124 which direct coolant to wheels 88,
86. By an appropriate valve arrangement coolant flow is
controlled so it is only directed to the grinding wheel 86,
88 which is in position for grinding. Coolant pipes 123,
124 which supply coolant to grinding wheels 86, 88 are
formed to move beneath pipe 122 when wheel head 84 is moved
to a selected position.
A Handel 102 through an appropriate gearing
arrangement can be used to rotate wheel head 84 around pivot
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connection 86. To position wheel head 84 to a desired
position bolted connections holding wheel head 84 to wheel
slide 76 are loosened. Handel 102 is then rotated to
bring wheel head 84 to the desired position. The fasteners
are then tightened holding wheel head 84 and wheel slide 76
for unitary movement. Stops and markings are provided at
various positions to provide for exact angular alignment of
,
wheel head 84 relative to wheel slide 76.
The above-described grinding machine is also described
and is claimed in above-identified cop ending parent
application Serial No. 393,273.
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The two fixed drowsy diamonds 36, 38 are
mounter to _ootstoc~ 26 for dressing grinding wheels 86
or US. Dressing is accomplished by moving carriage 56
and wheel slide 76 along their axes at programmed rates
and distances Jo produce the desired wheel contour which
may involve combinations of straight step diameters,
angles, chamfers and radii. A programmable microcomputer
in controller 12 is utilized for controlling the desired
movement of the wheel slide 76 and the associated grinding
wheels 86 and 88. Controller 12 is programmable to provide
for wheel form dressing of complex grinding wheel shapes
including combinations of shoulders, diameters, fillet
radii and angles connected at set inflection points.
Figures 9 and 10 are exemplary of the various combinations
of shapes which grinding center 10 can produce in grinding
wheels 86, 88. It should be clearly understood, however,
that these are not the limit of possible shapes and
numerous other combinations of shapes can be formed.
The diamond dressing arrangement consists of the
two diamonds 36 and 38 which are fixed to foot stock 26 in
front of the grinding wheel 86, 88. The two diamonds are
offset from each other in the two planes of wheel head
axes motions, along the X-axis and Z-axis. The x-axis
and taxi offsets ale shown in Figure 9. The right hand
dressing diamond 38 is used for all dressing of wheel
shapes, which may involve combinations of straight and
increasing wheel diameter segments, as the grinding
wheel 86, 88 is moved past the diamond 38 in a right to
left direction (- z axis direction). The let hand
dressing diamond 36 is used for all dressing of wheel
shapes when the grinding wheel moves past diamond 36 in
a left to right direction (I z axis direction). The wheel
dressed shapes may include combinations of straight and
increasing diameter segments. Of course, it necessary to
achieve the desired shape, the grinding wheel may be also
moved intermittently or simultaneously in the front to
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rear direction (x-axis direction).
Tile x-axis offset and the z-axis offset are
mozzarella 'my touching off with the grinding wheel 86, 88
in the initial set up of grinding center 10. The x-axis
and the Zeus offsets are when used to offset controller
12 such that dimensional control and blending of the
wheel shape segments dressed by each diamond 36, 38
relative to the other will be achieved automatically.
In actual usage of the two-diamond set up the two diamonds
will not wear uniformly and this will change the x-axis
and z-axis offsets between the two diamonds 36,-38.
Compensation for this non-uniform diamond wear is easily
achieved by adjusting the offsets in controller 12.
kite a two dressing diamond arrangement is
presently preferred, the same results could be obtained,
as illustrated in Figure 11, with a single diamond 35.
Single diamond 35 is automatically swiveled from a right
hand orientation to a left hand orientation when the
z-axis direction of grinding wheel movement during
dressing changes. Fixed stops are provided for accurately
locating dressing diamond 35 in the right hand and left
hand positions and the offset between these two positions
can be entered into controller 12 as descried previously.
Grinding center 10 has the capacity to grind
different configurations using straight and angle wheel
setups. Grinding center 10 combines straight slide
grinding machine features and angular slide grinding
machine features without the need for changing grinding
wheels or reshaping grinding wheels. Contour dressing of
the grinding wheels is programmable by two-axis motion to
produce complex forms and eliminating the necessity for
truing devices and form bars. The disclosed carriage guide
system for the carriage traverse movement minimizes the
effects of thermal and grinding load distortions.
