Патент USA US2610454

Sept. 16, 1952
` `
D. A. CARGILL
2,610,449
AUTOMATIC MILLING CUTTER GRINDER
3 SheetTs-Sheet 1
,Filed Nov. e, i948
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Sgpt. 16, 1952
-D. A. CARGILL
2,610,449
-AUTOMATIC MILLING CUTTER GRINDER
F‘iled Nov. 6, 1948
3 sheets-sheet 2
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Sept. 16, 1952
D. A. CARGILI.
2,610,449
AHIDOMATIC MILLING CUTTER GR_1NDER
Filed Nov. 6, 1948
5 Sheets-Sheet 5
6'0‘
2,610,449
Patented Sept. 16, 1952
UNITED STATES PATENT OFFICE
Don A. Cargill, Birmingham, Mich., assigner vLto
General »Motors Corporation, Detroit, AMich», -a ‘
corporation of Delaware
Application November 6, 1948, -Serialhlm-58,719
.
’
__
A11 Claims.
(Cl. 5ï1--123ì
2
fl .~
and vinexpensively formed of top »andbottom‘hori
This .invention relates ito grinding .machines
zontal plates I6 `and i8, welded or otherwiseper
manently vsecured «.to a >vertical -plate 20 which
forms -the back of 4the enclosure `and extends
above the same to provide a rigid mounting -for
and 'particularly :to .a machine 'for successively
grinding a `r.plurality .of .circumferentially `:spaced
'and similarly ¿inclined ’surfaces on a work piece,
'such as "for example, the tooth faces on a vface
millingcutter.
tlieïgrinding wheel >motor I3. Removable-plates
22, .Z4-and ¿26 are provided "tolcomplete *the fr_e
‘
'It'isthegeneral object of 'the invention to pro»
vide -such a machine with ywhich such operations
maining three »sides'of the enclosure.
~
The top plate I6 of the frame 2 has an aperture
can »be performed more accurately and rapidly
than A*has -been possible or ypracticable heretofore.
through which extends a cylindrical nsleeve mem
ber 28 which-is `anchoredat-its -upper end'to'the
top plate rIï6 and -anchored at >its lower end "to a
horizontal
brace member 30 >which -is anchored
construction which Aperforms -such voperations
the vertical plate 20 and is also tiedto the top
with asurçface grinding action and ¿in which the 15 to
plate I6 by a vertical brace member 432. Lining
work
automatically indexed `and vfed to the
the sleeve member 2-8 is an `upper bushing 34
Agrìndingwlheel.
which
journals the spindle 4.
'The means rby'which these .and other objects
The upper end of the spindle >l4 isp-rovided with
and advantages »are 'obtained Lis vclearly described
-.More -specifically 'it is -an object of the .inven
tion to :provide :a machine of cheap and simple
hereinafter, >reference being made to the draw
ings,-in':which:
a .reduced diameter portion 35 having means such
as the Vstud 36 and nut 38 for coaxiallny securing
20
f
a work piece such asa milling _cutter 6 ‘having
"Figure 1=1 is >an elevational yview of a Amachine
cutting teeth` 1.
forming a specific embodiment of my invention,
Withfparts vbroken away-and 'insection and show
ing theoutlinelo'f la ymilling cutter installed there
onlforgrinding.
chine’s work Tfeeding mechanism.
'
Figure 4 is van ¿enlarged view 'of a portion of
the‘mac'hine taken ‘from line 14--4 of Figure l,
» f
member 42^which is anchored lby a second hori
Figure ’2 -is an enlarged-view ‘of a portion of the
machine taken from line 2-2 of Figure l, with
parts broken yawayßand in section.
Figure 73 iis an enlarged >fragmentary view in
perspective showing certain details of the ma
'
ASpaced vbelow l_the ¿sleeve ‘member 28 and Vin
alignment with the upper >bushing34 therein is 'a
lower bushing `4l] flxedly supported vin a lring
zontal brace member `44 tothe vertical plate ‘20
and verticalbrace member32. The upper end
ofthe lower ibushing 40 Vis ñangedoutwardlyand
30 provides a thrust bearing surface'for a rotatively
' movable ring 46 4disposed coaxially of the -spindle
4 vand :having a worm wheel 48 removably secured
thereto as by screws 49 _and 5l. The_spindle 4
with parts 'ibroken -away and 'in section.
'Figure A5 viis >an «elevational view illustrating «a
tooth àor" va milling cutter Y:being ground on `the
machine ïin various »stages of its movement into
is vfreely'slidable longitudinally through the mov
able ring 46 butis'locked against relative `rotation
therewith by ,the 'key 50 which is secured >by Athe
screw 5_,2 ’in ¿a recess -54 .in _theíbore _of the .ring
4.6 .andprojects into .a >long (groove .56 .on the ex»
andfoutrof engagement with the grinding Wheel.
'Figureiö showsanenlargement of the working
terior ofthe spindle'4.
cably-driven‘vertical spindle 4 adapted to lcarry
6|),as shown, extends 'through ¿the vertical plate
20 ~and 'is Vdrivably .connectedto-a motorëál, .as by
`withîthe .Worm wheel 48isa Worm ylit
surface contour-oiga .rotary cam employed in the 40 onInimesh
_a shaftpûß journaled .in _the vertical plate 2li
machine, `'and »a lift velocity »diagram thereof.
and 'in a bearìngäsupport _plate S82 which is an
>Referring -to 'the drawings, ythe machine com
chored to the -Ibottom plate >lil .and to the two
prisesastationary supporting'structure or frame
horizontal
brace members .3.0 and 44. Theshaft
2 >in'which is Imounted »a rotatably and recipro
a milling cutter 6 or :other work piece into inter
mittent engagement withv an vabrading member
such :as a vgrinding‘wheel 8. The latter may, >as
shown, .be >directly 'driven‘by‘the spindle .or .shaft
lllof an -electric motor I-3 supported through :its 50
spindle bearing ¢I~2 and .adjustably positioned and
secured to the v-frame 2 by a clamp I4.
The Vframe y-2 forms -a box-like enclosure 'for
the ¿belt -ßßrunning over pulleys 68 and 18.
l
The spindle .4 Ais vertically supported by a -lever
'l2 Vdisposed .transverselyof the spindle axis vbelow
thelowerendof the spindle. ÍThebottQm end-of
thespindle 4 _is A»provided centrally .thereof with‘fa
conical recess .orsoclçet 14 lftoreceive a ball f7.6
whichrests one variable thicknessspacermember
such-as `the .Wedge ~18_,¿~whioh 1in turn rests Vonthe
the movable parts `employed in controlling the
movements of the spindle 4, vand maybe simply 55 lever »1.2. The lwedge «18 extends transverselyof
3
2,610,449
the lever 12 and is laterally supported thereon by
two guide blocks 80 and 82, most clearly shown in
Figure 3, which are ñxedly secured to the frame 2
through a vertical brace member 84 extending
from the ring member 42 to the bottom plate I3.
The Wedge 18 is slidable transversely of the lever
12 and also vertically in a groove 86 formed by
4.
working face |06 synchronizes the rate of lift of
the spindle 4 with the rate of rotation of the
spindle, and causes the various teeth 1 of the mill
ing cutter 6 being ground -to move in respective
parallel planes during that portion of each revolu
tion of the cam 96. Figure 5 illustrates the pro
gressive movement of a milling cutter tooth 1 as
an upwardly open recess in the side of the guide
it is brought into'and out of engagement with the
block 82 adjacent the guide block 80. The groove
working face |05 of the grinding wheel 8, the
86 is of sufficient depth both to provide ample 10 line |01 representing the plane within which that
lateral support for the wedge 10 when the lever
portion of the movement occurs While the con
12 is in its uppermost operative position, and to
stant velocity lift section of the cam working face
prevent the wedge from bottoming therein when
|06ris in operation.
the lever is in its lowermost position. The top
The maximiun lift height of the cam working
faces of the guide blocks 80 and 82 may be relieved
face |06, which with the contour illustrated in
or notched as shown at 88 in Figure 3, to prevent
Figure 6 occurs at the 140° position, may be
their interfering with the ball 16 when the lever
chosen in accordance with the size of the milling
is in its lowermost position. As best shown in
cutters intended to be ground on the machine.
Figures 2 and 3, the bottom face 90 of the wedge
18 is rounded t0 provide approximately line con 20 For grinding the standard range of face milling
cutters used in machining automotive crankcases,
tact with the lever 12, and the top face 92 on
cylinder heads, and the like, a maximum lift
which the ball 16 rests is inclined in a _direction
height of approximately 1A; of an inch was found
longitudinally of the wedge to provide for variably
to be satisfactory in the machine shown.
adjusting the height of the spindle relative to the
The pin 04 which serves as the fulcrum for the
lever 12. Moving the wedge 18 to the-right as
lever 12 is mounted in a bracket |08 which is
viewed in Figure 2 operates to raise the recipro
releasably clamped, as by a plate || 0 and bolts
catory stroke of the spindle and thereby feed the
||2 and H4, to a horizontal rail l‘lßñxedly se
milling cutter 6 (or other work) to the grinding
cured to the frame 2 through the vertical brace
wheel 8.
The lever 12 is fulcrumed at one end on a pin 54 30 member 84 and a pedestal IIS. The location of
the bracket |08 along the rail |10 determines
for oscillatory movement in a plane through the
longitudinal axis of the spindle 4 in response to
movements of a single lobed rotary cam 06 upon
which its opposite end rests and which is drivably
carried on acarnshaft 08 journaled in the plates
20 and 62. Camshaft 03 and shaft 60 are posi
the distance of the fulcrum pin‘ 94 from the
spindle 4 and cam 06, and thus the veffective
length of the lever 12, which in turn determines
the length of stroke of the spindle 4 effected by
the camV 06. And, since the cam 06 is geared to
the rotation of the spindle 4, the length of the
stroke of the spindle determines the speed of its
reciprocatory movement. Further, since the rate
at a drive ratio such that camshaft 98 makes the
same number of revolutions per each revolution 40 of lift of the spindle is ‘synchronized with its
speed of rotation during the portion of the stroke
of the spindle 4 as the number of teeth on the
when the uniform velocity lift section of the cam
milling cutter 6 being ground. When milling
06 is in service, by increasing or decreasing the
cutters having greater or lesser numbers of teeth
reciprocatory stroke an adjustment is obtained of
are to be ground, the gearing together of cam
the inclination, relative to the spindle axis, of
shaft 98 and shaft 60 must be changed accord
the parallel planes through which the milling
ingly, in order that the same relationship is main
cutter teeth move during that portion ofv the
tained between the number of cutter teeth and the
speed of the camshaft. In the case _of the par
An externally threaded lead screw |20, having
ticular machine shown, such a change in gear
a C-shaped extension |22 slidably supported in
ing is accomplished by removing. gears |00 'and
a groove |24 between the guide blocks 80 and
|02 from their respective shafts and substituting
82, is provided for movably adjusting the location
other gears (not shown) providing the required
of the wedge 18 transversely of the lever 12. The
driving ratio.
. .
.
extension |22 embraces opposite ends and one
The cam 96 is designed to operate in the direc
side of the wedge 18, as shown in Figure 3, the
tion of the arrow |04. As shown in Figure 6, a
wedge being free to move vertically relative there
contour for the working surface |06 which has
to in response to the oscillatory movements of the
proved entirely satisfactory consists of succes
lever 12. Threadedly engaging the lead screw
sively adjacent sections blended together and pro
|20 is a circular nut |26 which is free to rotate
viding respectively 40° of uniform acceleration lift
thereon but is anchored longitudinally thereof by
(320°-360°), 100° of uniform velocitylift (360°
tively geared together, as by intermeshing gears
|00 and |02 removably ñxed thereto respectively,
stroke.
,
'
100°), 40° of uniform deceleration lift (loot-140°) , 60 a finger member |28 engaging a peripheral groove
|30 therein and fìxedly secured as by the screw
60° of uniform acceleration drop (140°-200°) , 60°
|32 to the stationary guide block 82. The nut
of uniform velocity drop (200°--260°), and 60° of
|20 has outwardly extending flange portions |34
uniform deceleration drop. While various other
and |36 defining the groove |30 and an external
contours might be employed for the working ysur
face |06, that which is illustrated and just de 65 ly threaded reduced diameter portion |38 extend
ing coaxially thereof through an aperture |40
scribed has two advantageous features which are
in the removable front plate 24 of the frame 2.
preferably to be retained in any modification
A crank |42 is connected to the reduced diameter
thereof, namely, a, single lobe, and a uniform
Iportion |38 for manually turning the nut |20.
velocity lift section. A single lobe cam insures
equal lift of the spindle 4 (through the lever 12) 70 Threadedly engaging the reduced diameter por-y
for each tooth of the milling cutter being ground,
tion |38 of the nut |26 is an internally threaded
thereby eliminating the camfrom any possible
lock nut |44 journaled in the aperture |40 and
contribution to milling cutter run-out (variation
having an outwardly extending flange portion
in height between respective teeth) during grind
|46 disposed opposite the flange portion |34 of
ing. And the uniform velocity lift section of the 75 the nut |26. Between the flange portions | 46 and
acid-‘44.9
the pivoting of lever f12gbeing-,neglectable in'view
of theasmall-amplitude- of »lift involved) ,with the
A|34 -and journaled Aon ashoulder |43 on the .-nut
|20 isa peripherally -toothed member or star
wheel |50 'which "is adapted to Aloe .rotated -in
step-by-step V«fashion vwith each successive yrota
result -thatïthe upper vfaceaof »each 'cutting »tooth Fl
moves‘in a continuousfplane, representedby the
line -|-01‘in Figure 5,-during thatjperiod. The in
clination of this plane-relative »to the horizontal
depends kon .the effective length of the lever 12,
whichis adjusted by shifting ,thev fulcrum pin sup
porting :bracket |08 :along -the rail |||ì either
tion'ofthe spindle~4 by an arm |5| fixed Íto the
movable ring 46 as by »the screw 5|. A hand
wheel |52, Vjournaled `on the lock nut |44 «and
slidable longitudinally thereof, is lprovided Ywith
a-.set screw |54 which -canfbe releasably brought
toward -or away «from the cam 96.
into engagement .with a slot y|50 inthe lock nut
_Y whenever it is desired toy rotate vthe `latter `in
order toelfect 4a clutchingengagement or disen
gagement ofthe starwheel r|5|) with <respect `_to
wheel 8.
the .nut |26. When the star »wh-eel `|50 Ais fric
l
the respective ñange
, tionally 4clutched between
portions .|34 >Yand |48 of the nuts '|26 >‘and |44, v-the
number of .times per revolution thereof as there
are 4teeth 1 or likegporti'ons to be ground on the
beginning .(or end) of »each revolution of the
spindle 4, lwhich in turn, effects an incremental
axial -movementof the lead screw |20 and y-a yre
sultant >incremental Iraising of the reciprocatory
.
'
Since the spindle 4 must reciprocate 'the same
nut rotatesa predetermined incr-,ement at Íthe
stroke of the spindle.
With the
bracket |08 located the ¿properdistance from the
cam, theplane ,referred ‘to will be ,parallel with
thejplane of .the working face |05 of the grinding
s
work piece, and since such number of reciproca
tions per revolution directly affects >the speed lof
its axial movement independently of its ¿rotary
movement, lthe proper location of Athe bracket |08
on therail |f|6 to-obtain a desired angle of grind
will need to be'varied' to accommodate work pieces
The operation of `the machine, although .be
having such different numbers of teeth. >As-a
lieved to be already `apparent from the descrip
convenience, lin facilitating theiproper locationof
25
tion _heretoforegiven of the .functions of its var
the bracket |08,v :markings or other reference
be
summarized.
A
mill,
ious elements, will now
points (notshown) vmaybe placed on therail | |'6
ing cutter 6 or other work-piece having‘projec
to -,indicate ¿the ¿positions lcorresponding to the
tions in the nature of cutter teeth V1 to be ground
most :commonly Y used combinations of desired
is first ¿placed on the vupper end of `the yspindle
4 and clamped securely-by the nut 3.0. By ad» .30 clearance -angles'and cutter teeth numbers.
Prior to‘the ,positioningaof the grinding wheel >8
justment of the-clamp i4 relative to the frame
by.
adjustment ofthe clamp |4,‘as earlier-referred
back member vr20 the .grinding wheel .8 is posi
to, the lead screw |20 is .backed out by rotating the
tioned over .the work, such. that the wheel work
handïcrank »|42 to withdraw the wedge 18 va sufii
ing face |05 is inclined from the horizontal by
cient distance to the left, as .viewed inFigure v2,so
the amount of the clearance angle with which it
that the ball 16 .rests thereon near `thelower r`end
is desired to provide the cutter teeth .1, and such
that 'the peripheral edge of the wheel working
face |05 is approximately tangent toa vertical
of 4its inclined top >face 192.
l
The motors I3 and B4 are then started and the
hand crank |42 is .rotated toraise the reciproca
stroke >of the spindle until the upper faces
reciprocatory 40 tory
of the .cutter teeth just miss contacting the
by means .of
grinding wheel as they :successively rotate there
through the
under at the upper end of the spindle stroke.
a rotation of
Hand wheel | 5-2-is vthen interlocked with the lock
plane through one .of the cutter teeth when the
spindle 4 is at the .middleof its
stroke. Rotation of the shaft .80,
the motor .64 connected thereto
pulleys 68, 1.0 ,and belt 65, effects
the spindle 4 through the worm 58 and worm
nut |44 and thelatter is threaded up on the nut
wheel 48. Shaft 08 vrotates concurrently with
|26 to clamp them Linto frictional engagement
shaft ,60, .being geared >thereto by gears |00 and
with the-star wheel |50 which is intermittently
|02 which ‘1t-Will be .assumed have been vselected
rotated by the arm |5| rotating with the spindle.
to »provide the proper drive ratio, at `a speedîequal
Once each revolution thereafter the arm |5| en
to therotative speed of the spindle 4 times the
gages the star Wheel .| 50 androtates the same one
number of teeth _1 -onithemilling cutter 40 which is 50 tooth,
rotating .the nut |26 by the same degree
to be ground. >Any deviation vfrom this driveratio
and -effecting an incremental advance of the lead
must be correctedbychanging gears |00 and v.|02
screw |20 and wedge 18 toward the spindle, which
for other gears which will .provide .the same. The
in Yturn raises the reciprocatory stroke of the
cam '90 îbeing Qdrivably carried by theshaft *.98
spindleand lfeeds the milling cutter 6 or other
will therefore rotate îand effect an `oscillatory
workpiece a definite amount toward the grinding
movement of the lever L12 >about its fulcrum pin
wheel
8.
94, which movement, will be transmitted or con
Sinceithe cutter teeth 'i' successively engage the
verted into a vertical reciprocatory movement‘of
working .face |05 of the grinding wheel while
the wedge 18, ball 15 and spindle '4 .as a unit.
moving in a plane parallel thereto, a surface
Reciprocation of _the >spindle concurrently» with
grinding actionis obtained. Such a grinding ac
its rotation .is permitted by the ~extended length
tion, as is Well known, has important advantages
cf the .groove '56 whichallows it to slide relative
over -a plunge type .grind in accuracy and quality
to the key 50 affixed to the worm wheel 48.
ofthe ñnished Work,.grinding wheel life, etc.; and
Due -_to _the contour of the working face |08 of
the camiSB (see Figure‘ô) , the spindle 4 in rising
from its lowermost to >its uppermost position
moves first at a'uniformly increasing velocity for
a limited distance, then at-a constant velocity for
an extended distance,«and finally slows with uni- .
formly decreasing velocity of movement as it ap
preaches -its uppermost position. ilîts upward
movement at »constant velocity'V is -substantially
synchronized with its rotative movement by rea
son of the gearing together of the two shafts G0
Y its achievement in a simply constructed machine
providing automatic indexing and feeding ofthe
work is one of the principal advantages yobtained
by -my invention.
It is also pointed out that by reason of the .in
stant machine employing a single `lobed cam to
effect the reciprocation of the work piece, each
tooth or other portion of the latter being ground
is advanced the same :distance , into v.contact -with
the grinding Wheel, Vresulting in the complete
avoidance of ytooth Arun-out .from a .practical
and 98 (the slight distortive . effect produced by 75
2,610,449
7
8
standpoint. Further, the use of a single lobed
means including a uniform velocity lift cam oper
cam arranged with a pivoted lever follower ad
ative through a pivotally supported follower
against the opposite end of the spindle lever to
justable in effective length, all in accordance
with this invention, enables the machine to
effect a uniform lineal velocity ofthe spindle dur
ing its advancement toward the grinding wheel,
accommodate milling cutters or like work pieces
of a variety of sizes and types.
said lever having 'its pivotal support on said spin
dle supporting means the effective length of said
follower lever being adjustable to coordinate the
lineal and rotary velocities of the spindle in order
The specific form and construction of the
machine as shown in the drawings and described
herein was chosen with the view of building a
single machine or very small number thereof at
a minimum cost, and~ it is appreciated that vari
ous structural modifications and refinements will
readily suggest themselves to persons skilled in
this art.
I wish to further point out that the terms and
expressions used herein are to be considered in
their descriptive rather than their limiting sense,
and that the scope of my invention isV defined
that successive teeth on the cutter engage the
grinding wheel in the plane of its face.
4. In a milling cutter grinding machine, a spin
dle on which a grinding wheel may be mounted,
a spindle on which a milling cutter may be
mounted, supporting means for said spindles,
means for rotating the milling cutter spindle at
a uniform velocity, means for longitudinally
reciprocating the >milling cutter spindle at a fre
d_uency whose ratio to the angular velocity of
the milling cutter spindle is equal to the number
solely by the appended claims.
I claim:
Y
l. In a machine for surface grinding milling
of teeth on the milling cutter, including a cam
having a working face provided with a uniform
cutters and the like, a grinding wheel, supporting
means for said wheel, a spindle for carrying a
velocity lift section operative during the engage
ment of each successive tooth of the cutter with
the grinding wheel, a lever connected to the mill
milling cutter into contact with the wheel, means
supporting said spindle for rotary Yand reciproca
tory movement, means‘ffor rotating the spindle
at a uniform velocity, meansv for reciprocating the
spindle toward and away from the wheel once for
Y
each tooth of the cutter during each revolution
of the spindle, including a cam‘having a 'working 30
face provided with a uniform velocity lift section
operative during the advance stroire of the spin
dle, a lever actuated by the cam and operatively
engaging the spindle for transmitting the move
ment of the cam to the spindle, a fulcrum sup
ing cutter spindle for transmitting the movement
of the cam to the milling cutter spindle, said lever
being fulcrumed at one end and having its free
end engaged by the cam, and means for adjusting
the fulcrum of the lever to vary the reciprocatory
stroke of the milling cutter spindle and thereby
regulate the speed at which the teeth of the mill
ing cutter are fed to the grinding Wheel, the ful
orum for said lever being supported by said spin
dle supporting means.
porting said lever, and means for adjusting the
5. In a grinding machine for sharpening the
fulcrum of the lever to vary the length of stroke
teeth of milling cutters, a machine frame, a ver
and thus the reciprocatory speed of the spindle.
tical spindle rotatably and reciprooably supported
2. In a surface grinding machine for multi
toothed face milling cutters and the like, a grind 40 therein and provided with means at its upper end
for coaXially securing a milling cutter to be
ing wheel, supporting means for said wheel, a
sharpened,
a Worm wheel thrustably supported
spindle for carrying a milling cutter, means sup
by
the
frame
and having a coaXially slidable and
porting said spindle for rotary and reciprocatory
rotary driving engagement with the spindle belowmovement, means for rotating the spindle at a
the milling cutter, driving means including a first
uniform velocity, means for reciprocating the
shaft
journaled in the frame and carrying a worm
spindle toward and away from the wheel once
in mesh with the lworm wheel, a rotary cam for
for each tooth on the cutter during each revolu
effecting reciprocation of the spindle, a second
tion of the spindle, including a cam having a
shaft in coaxial driving engagement with the cam
working face provided with a uniform velocity
lift section operative in cooperation with the uni- l
form speed of rotation of the spindle to cause the
face of each successive cutter tooth to move in a
continuous plane during its engagement with the
grinding wheel, and a lever operatively comiect
ing the spindle to the cam for transmitting the
movement of the cam to the spindle at a ratio
such that Said plane extends parallel with the
working surface of the grinding wheel, said lever
having a supporting fulcrum on said spindle sup
` porting means.
and geared to the ñrst shaft, a cam follower dis
posed transversely of the spindle and pivoted to
the frame about a horizontal axis offset from the
axis of the spindle, a variable height spacer mem
ber resting on the follower and vertically support
ing the spindle thereon, and screw means geared
to the rotation ofthe spindle for slidably moving
the spacer member a predetermined distance rel
ative to the follower at the end of each revolution
of the spindle.
6. An automatically self-indexing milling cut
3. In a milling cutter grinding machine, a GO ter grinding machine, comprising a Work spindle,
rotatably and reciprocably movable spindle hav
ing means adjacent one end for coaxially securing
a milling cutter, means rotatably supporting said
spindle and guiding its reciprocatory movement,
a grinding wheel having a generally iiat grinding
face opposite said spindle end and tilted from a
position normal thereto by the amount of the
clearance angle with which it is desired to grind
the faces of the cutter teeth, supporting means
for said grinding wheel, means for rotating the
spindle at a uniform velocity and means for lon
gitudinally reciprocating the spindle the same
number of times per revolution thereof as the
a support journalling and reoiprocably guiding
said spindle, means for imparting a continuous
axial rotation to the spindle, a single lobe cam
on said support geared to said means and adapted
65 to impart a concurrent longitudinal reciprocation
to the spindle, means for longitudinally shifting
the reciprocatory stroke of the spindle, and an
abrasive member mounted on said support rela
tive to the longitudinal and rotational movements
of the spindle for contacting successive teeth of
the cutter with each reciprocation of the spindle.
'7. An automatic milling cutter grinding ma
chine, comprising a rotatable and reciprocable
number of teeth on the cutter, said reciprocating 75 spindle having means adjacent one of its ends
for attaching a milling cutter, a support jour
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nalling and reciprocably guiding said spindle, an
10
ment with the second gear, a rotary cam, a sec
ond shaft in coaxial driving engagement with the
abrasive member on said support, driving means
cam, a gear train drivingly interconnecting with
for continuously rotating the spindle, and means
the first and second shafts, a lever having a free
including a single lobed cam geared to said driv
end slidably resting on the cam and a fixed ful
ing means and a pivoted follower in operative
crum laterally distant from both the cam and the
engagement with the cam for effecting a recipro
spindle, a wedge member slidably spacing an end
cation of the spindle in timed relation with its
of the spindle from the lever, a screw-thread
rotation, said cam and follower being mounted
means interconnecting the wedge member and
on said support.
said first gear for effecting endwise movement of
8. An automatic milling cutter grinding ma 10 the lwedge member transversely of the spindle,
chine, comprising a rotatable and reciprocable
and means supporting each of the aforesaid ele
spindle for carrying a milling cutter to be ground,
ments for their relative movements as defined.
a support journalling and reciprocably guiding
1l. In an automatic milling cutter grinding
said spindle, an abrasive member on said support,
machine, a rotatable and reciprocable spindle
15
driving means for the spindle, gearing operable
having means adjacent one of its ends for attach
from said driving means to effect a continuous
ing a milling cutter, driving means for continu
rotation of the spindle, other gearing including
ously rotating the spindle, and means including
a constant velocity lift cam mounted on said sup
port and operable from said driving means to
effect a continuous reciprocation of the spindle. 20
9. In a machine for surface grinding millingl
cutters and the like, a grinding wheel, a spindle
'
for carrying a milling cutter into contact with
the wheel, means for rotating the spindle at a
uniform velocity, means for reciprocating the
spindle toward and away from the wheel once
for each tooth of the cutter during each revolu
tion of the spindle including a cam having a
work face provided with a uniform velocity lift
section operative during the advance stroke of 30
the spindle and a lever actuated by the cam and
a single-lobed cam geared to said driving means
and a pivoted follower operatively disposed be
tween the cam and the opposite end of the spindle
for transmitting movement of the cam to the
spindle, a variable thickness spacer means slid
ably interposed between the lever and said spin
dle opposite end, and means rotatively geared to
the spindle for shifting said spacer means trans
versely of the spindle at the end of each complete
revolution of the spindle, and means supporting
each of the aforesaid elements for their relative
movements as deñned.
operatively engaging the spindle for transmitting
the movement of the cam to the spindle, and a
variable height spacer member slidably resting
on the lever and vertically supporting the spindle
thereon, and means for shifting said spacer mem
ber transversely of the spindle to shift the recip
rocatory stroke of the spindle longitudinally of
the spindle axis.
»
10. In a grinding machine for grinding milling 40
Y cutters and the like, a rotatable and reciprocable
spindle for mounting the milling cutter to be
ground, a first gear in coaxial driving engagement
with the spindle, a second gear in mesh with the
ñrst gear, a first shaft in coaxial driving engage 45
ì
DON A. CARGILL.
REFERENCES CITED
The following references are of record in the
file of this patent:
UNITED STATES PATENTS
Number
Name
Date
1,285,124
1,326,462
Gleason __________ __ Nov. 19, 1918
Murch ___________ __ Dec. 30, 1919
1,841,244
2,108,310
2,332,420
2,452,989
Gstyr ____________ __ Jan. 12,
Grifñng __________ __ Feb. 15,
Wildhaber ________ __ Oct. 19,
Brown ____________ __ Nov. 2,
1932
1938
1943
1948