Note: Descriptions are shown in the official language in which they were submitted.
207 666~ 1
MILLING MACHINE
Field of the Art
The present invention relates to mechanical engineering
and more Particu1ar1y to mi11ing machines.
Background of the Invention
Well known in the art are milling machines adapted for
milling contoured slots and producing intricate and repeat-
ing patterns and relie~s. UsuallY each working motion of the
table and of the working spindle in such machines is effect-
effected with the help o~ an individual comPuter-controlled
drive. Such a system re~uires that the machine should be
provided with a large number of electric drives and with a
sophisticated electronic control system comprising a central
~ processor, -a sensor, and other elements of the automatic
control system. This involves an increase in the power con-
sumption and weight of the machine, makes the machine serv-
- icing more complicated, and adds to the cost of the machine.
~nown in the art is a milling machine comprising a bed,
a working table for clamping workpieces thereto, mounted on
the bed with the possibility of travel and provided ~ith a
drive ensuring its movement relative to the bed; a platform
mounted with the possibility of movement relative to the bed
and carrying at least one spindle head intended for securing
a working tool; and a mechanism for ensuring relative move-
ment of the working table and the platform (SU, A, 1511124~.
This machine is noted for a simple desi~n, its working
motions are ensured by purely mechanical means from one
' drive. The mechanism for ensuring relative movement of the
working table and the platform comprises a pair of eccen-
trics, horizontal plates and vertical plates, arranged in
~uides of said horizontal Plates and transmittin~ motion to
the platform carrying the spindle heads. This milling ma-
' chine is disadvantageous in that it cannot provide curvi-
linear Patterns and intricate reliefs, because the working
platform and the spindle heads can perform onlY a limited
number of working motions. Furthermore, the machine is pro-
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207666~ ~
vided with a cumbersome mechanism for ensuring relative
movement of tne working table and the platform. This mech-
anism is a source of losses of the drive nechanical energy
because of friction experienced by the vertical plates in
the guides. This makes the machine inefficient and un-
reliable in operation.
Disclosure of the Invention
The present invention is directed to the provision of a
milling machine, in which a mechanism for ensuring relative
movement of its working table and platform is designed so as
to secure by purely mechanical means a plurality of differ-
ent combinations of the working motions of the machine mem-
bers.
- Said object-is accomplished by that in a milling ma-
chine comprising a bed, a working table for clanping work-
pieces, mounted on the bed with the possibility of travel
and provided with a drive ensuring its movement relative to
the bed; a platform mounted with the possibility of travel
relative to the bed and carrying at least one spindle head
intended for securing a working tool; and a mechanism for
ensuring relative movement of the working table and the
platfor~, according to the invention, the mechanism for en-
suring relative movement of the working table and the plat-
form is made in the form of at least two pairs of eccentrics
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disPosed on both sides in relation to the path of travel of
the working table, one of the eccentrics of each pair, name-
ly, the inner eccentric, being disposed inside the other,
outer eccentric, which is mounted on the platform carrying
the spindle head with the possibilitY of rotation and fixing
its Position relative to the outer eccentric and is kinema-
tically linked with the drive ensuring the motion of the
working table relative to the bed. The spindle head is
mounted with the possibility of travel relative to the plat-
form and is provided with a drive for ensuring its movement
relative to the platform, said mechanism being kinematically
linked with one of the eccentrics.
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207~6~
Such an arrangement ensures an infinite variety of com-
binations of the eccentricities of the two eccentrics; this
- feature allows anY versions of a repeating ~eometrical pat-
tern to be produced on the surface being worked. In com-
bination with the movement of the spindle head, provided by
the same drive, an additional infinite variety of pattern
versions is ensured; ail the working motions of the machine
are effected from one drive with the help of purely mechan-
ical means.
The outer eccentrics are Preferably mounted on the
platform rotatably and with the possibility of fixing their
position relative to the platform. In this case the adjust-
ment for varying the co~bination by the eccentricity of the
---- - eccentrics is simplified. --
The drive for moving the spindle head relative to the
platform preferably comprises a carrier installed on the
inner eccentric rotatably and with the possibility of fixing
its position relative to the inner eccentric. This provides
adjustment of the phase of the spindle head travel.
The outer eccentrics are preferably kinematicallY in-
terlinked. This ensures precise adjustment of the eccentri-
: city.
Each outer eccentric is Preferably made with an extern-
al cam surface having a elevation in the direction perpendi-
:- ~5 cular to the plane of the working table, and the platform is
provided with a carrier for interacting with said cam sur-
face.
~ This ensures additional motion of the platform with the
; spindle heads, effected by the same drive, ~or producing in-
tricate surface reliefs.
'~ Each outer eccentric preferably has a worm wheel in-
stalled for movin~ together with the platform and rotatably
.~ relative to the platform, the carrier being fixed rigidly in
: said worm wheel; a shaft is mounted rotatablY in the plat-
~orm and has worms fixed rigidly thereon, said worms meshing
with said worm wheels. This ensures precise and simultaneous
2076~60 4
adjustment of the phase of the vertical travel of the plat-
~orm.
The drive for moving the working table is preferabl-
~made as a rack-and-pinion mechanism, comprising at least one
rack attached to the workin~ table, the pinion of the rack-
and-pinion mechanism is linked kinematically with a pair of
shafts, and each inner eccentric is rigidly fixed on one of
these shafts. This simplifies the design of the drive mech-
anism, minimi~es the consumption of power, and ensures high
accuracy of the relative working movements of the machine.
The outer and inner eccentrics of each pair of the ec-
centrics are preferably interlinked by means of a uorm-and-
worm gear, the worm of each worm-and-worm gear being dispos-
ed on the extsrnal eccentric. This ensures simple and pre-
cise adjustment of the mutual position of the eccentrics andreliable fixing of the eccentrics after the adiustment.
The spindle head is linked with the carrier by means of
an oscillating crank gear with a variable radius of the
crank. This provides additional versions of the working
movements of the spindle head along with the movements of
the platform carrying the spindle head.
Brief Description of Drawings
Given hereinbelow is a detailed description of the pre-
sent invention, illustrated by the accompanying drawings, in
- 25 which:
Fig. 1 is a general view of a milling machine according
to the invention, longitudinal section;
Fig. 2 is view A in Fig~. 1 (some units and parts of the
machine are conventionally not shown);
Fig. 3 is a section along III-III in Fig. l;
Fig. 4 is a version of the structure of a part of the
mechanism for ensurin~ relative travel of the working mecha-
nism and the platform, shown in Fig. l;
Figs. 5-20 show different adjustments of the mechanism
for ensuring relative travel of the working table and the
platform, and the corresponding patterns produced on ma-
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207666~ s
chined workpieces; in Figs. 6, 8, 10, 12, 14, 16 and 18 in
the upper part of each drawing a pattern is shown with the
working table being stationary, whereas in the lower part of
the drawing a pattern is shown with the working table in
motion.
Preferred Embodi~ents
The machine of the invention comprises a bed 1, in the
lower part of which a reversing driv~, 2 is installe~, kine-
~atically linked with a wor'~ing table 3, ~ounted on the bed
l with the possibility of ~oving along a path lengthwise of
the longitudinal axis 0-0 of the ~achine ~Fig. 3) and pro-
vided with units (not shown) for clamping a workpiece 4. The
bed 1 mounts a ~ovable platfor~ 5. The Platform 5 is mounted
~ movably relative to the bed l-and-carries two spindle heads
- 15 6. The machine is provided with a mechanism 7 for ensuring
relative movement of the working table 3 and the platform 5.
The mechanism 7 has two pairs of eccentrics 8, 9 and 10, 11
; ~Figs. 1, 3) disposed on both sides of the path of travel
; 0-0 of the working table 3. The inner eccentrics 8 and 10
- 20 are mounted rigidly on vertical shafts 12, 13 which carry on
; their free ends conical gears 14, 15 that are in ~esh with
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conical gears 16, 17 mounted on a horizontal shaft 18 linked
with the drive 2 through a r,eduction gear 19 (which can be a
gearbox or a variator).
~ 25 The outer eccentrics 9, 10 are mounted rotatably on the
,; inner eccentrics 8, 10. The outer eccentrics 9, 10 are in-
. terlinked with the inner eccentrics 8, 10 through worm-and-
worn gears, comPrising worm screws 20, 21 installed rotatab-
~: ly in the outer eccentrics 9, 11 and meshing with worm
wheels 22, 23 cut on the inner eccentrics 8, 10. With such
an arrangement the outer eccentrics 9, 11 can be rotated re-
lative to the inner eccentrics 8, 10 for adjustment, and
their mutual position after the adjustment can be reliably
~; fixed. It is obvious that other embodiments of the mechanism
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for adjusting the mutual position of the outer eccentrics 9,
11 and inner eccentrics 8, 10 are also possible, but the
structural embodi~ent describçd hereinabove should ~e pre-
~erred. The described structure ensures an~ combinations of
the eccentricities of the outer eccentric and the inner ec-
centric of each pair, ranging from their alignment, when the
total eccentricity is equal to the sum of the eccentricities
of the t~o eccentrics, to such a position, ~hen the total
eccentricity will be equal to the difference of the eccen-
tricities of the two eccentrics (for instance, to zero,when the t~o eccentricities are equal~. In this case the
value of the total eccentricitY defines the amplitude of
travel of the platform 5.
The spindle heads 6 are movably mounted on the''~platfor'm
15 5 on links 25, 26 disposed in guide openings 27, 28 of the
platform 5, and each spindle head 6 is provided with a mech-
anism for moving it relative to the platform 5. This mecha-
nism is a carrier 29 (30) mounted rotatably on the inner ec-
' centric 8 (10) with the possibility of fixing the position
of the carrier relative to the inner eccentric. For this to
be done, the carrier 29 (30) is provided with a worm screw
31, arran~ed rotatably in the inner eccentric 8 ~10) and
meshing with a worm wheel 32 cut in the inner eccentric 8
(10). With such an arrangement the carrier 29 (30) can be
rotated relative to the inner eccentric 8 (10) for adjust-
ment and their mutual position after the adjustment can be
reliably fixed. It is obvious that other embodiments of the
mechanism for adjusting the'mutual position of the carrier
29 (30) and the inner eccentric 8 (lO) are also possible,
but the structural embodiment described hereinabove should
~; be preferred. With suoh a structure of the mechanism for
moving the spindle head 6, the phase of travel of the spin-
dle head 6 relative to the platfor~ 5 varies, depending on
the angular position of the carrier 29 (30) with respect to
the inner eccentric 8 (10), as will be shown hereinbelow.
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2076~6~ 7
In the ~iven e~bodi~ent one of the spindle heads 6 is
provided with a mechanism for moving it in relation with the
platform 5 with a crank 33, installed on the carrier 29 and
articulated with the link 25. The crank 33 is ~ounted on the
carrier 29 with the aid of an adjusting screw 34 that inter-
acts with the internal thread ~not shown) of the crank 33.
The adiusting screw 34 is arranged in the carrier ~9 rota-
tably and, in combination with the carrier 29, the crank 33
and the link 25, it makes up an oscillatin~ crank gear with
a variable radius of the crank. With such an arrangement the
inclination of the elements of the pattern produced on the
workpiece 4 can be adjusted, as will be shown hereinbelow.
It is obvious that the second spindle head can also be pro-
vided with a si~ilar mechanism.
As shown in Fig. 1, the outer eccentrics 9, 11 have cam
surfaces 35, 36 on the external surface, having an elevation
in the direction perpendicular to the plane of the working
" table 3. The platform 5 has carriers 37, 38 (39~ secured
.i thereon for interacting with the cam surfaces 35, 36 (Fi~s.
. 20 1, 4). In the particular case (Fig. 4), instead of the cam` surface in the outer eccentric 9, 11 an annular slot 40 can
be made without the cam elevation, interacting with a carri-
er 39 arranged in a threaded openin~ 41 provided in the
platform 5. As shown in Fig. 4, the outer eccentrics 9, 11
may have simultaneously both the cam surfaces 35, 36 and the
annular slots 40. With the provision of the cam surfaces 35,
36, rotation of the outer eccentrics 9, 11 leads to vertical
displacenents of the carriers 37, 38 and to vertical move-
ments of the platform S.
As shown in Figs. 1, 3, thc carriers 37, .,8 are ri~idly
; fixed in wor~ wheels 1~, 43, mounted for joint novement with
the platform and rotatably with respect to it. A shaft 44 is
mounted rotatably in the platform 5. On said shaft 44 worms
45, 46 are rigidly secured (or cut). These worms 45, 46 are
in engagement with the worm wheels 42, 43. Rotation of the
shaft 44 brings about rotation of the worm wheels 42, 43 re-
2076660 3
lative to the outer eccentrics ~, 11 and leads to a ch~nge
in the position oE the carriers 37, 38 r~-lative to th~ cam
surfaces 35, 36, for changin~ the ph~se ef vertica' traiel
of the platform 5 relative to the r~orking table 3. In the
~ 5 embodiment shown in Fig. 4 resetting of the carri r into
- openings 41a, 41b ensures a change in th~ phase of vertical
travel of the platform 5 in relation of the working table 3.
The result of such change in the Phase of vertical t~ravel of
the Platform 5 ~ill be shown hereinbelow.
As shown in Fig. 1, the working table 3 is driven by a
rack-and-pinion mechanism, comprising two toothed racks 47,
48 attached to the idle surface of the working table 3 and
disposed parallel to the path of travel of the table 3 or to
the axis 0-0 (Fig. 3). The toothed racks are in engagement
with pinions ~9, 50 mounted on the hori~ontal shaft 18 link-
ed uith the drive 2 of the machine, as described herein-
above. The working table 3 is mounted on the bed l with the
help of guide rollers 51, 52. With such a design of the
.' drive the working table performs rectilinear motion with
resPect to the bed 1. Thereby, a recurring pattern is pro-
duced on the workpiece 4, Rith a period ~repeat) depending
; on the rate of rectilinear motion of the working table 3.
The spindle head 6 (Fig. 1) is provided with a device
for adjusting its position with respect to the link (25,
26), this device being, for example, a carria~e 53 with
stops 54. Furthermore, the spindle head 6 is provided with a
chuck 55 for securing a working tool 56, for example, a mil-
ling cutter for machining tHe workpiece 4.
: The above-described milling machine operates in the
following manner.
; Before the machine operation is started, the milling
cutter S6 is set on a required height and the spindle head 6
is brought to the required position by resetting the car-
riage 53 on the link 25 and by fixing it with the stops 54.
Once the drive 2 is switched on, the table 3 executes a lon-
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207666~
gitudinal translation or reciprocating ~otion through the
rack-and-pinion mechanism 47-S0 ~clefined by the design of
the reduction gear 13 or b~ the drive control s-~stem, which
is not shownj. The wor~piece 4 sxecutes a longitudinal
motion.
Rotation of the shaft 18 causes rotation of the inner
eccentrics 8, 10, which transmit rotation to the outer ec-
centrics 9, 11 through the worm-and-worm gears 20, 22 and
21, 23. The platfor~ 5 executes a oircular motion relative
to the table 3, if the sums of the eccentricities of the
eccentrics 8, 9 and 10, 11 are not e~ual to zero. It is
clear that the working tool 56 of each spindle head 6 also
performs similar circular motions.
- The carrier 29 linked with the inner eccentric 9 by the
worm-and-worm gear 31, 3~, brings the crank 33 in rotation.
The latter causes reciprocation of the link 25 and, together
therewith, reciprocation of the spindle head 6 in relation
to the platform 5. Thus, in the general case the spindle
head 6 executes a circular ~otion with respect to the work-
ing table 3 together with the platform 5 and a reciprocating
motion with respect to the platform 5 and the working table
3.
If the outer eccentrics are provided with the annular
slot 40 (Fig. 4), the platform 5 does not perform vertical
motions. If the outer eccentrics are Provided wïth the cam
surface 35, 36 and the carrier 39 is set in one of the
openings 41a, 41b (Fig. 4) or if the carriers 37, 38
interact with the cam surfaces 35, 36, the platform 5 recip-
rocates vertically with respect to the working table 3
together with the spindle heads 6. This brings about changes
in the depth of the pattern relief produced bY the milling
cutter 56 in the workpiece 4.
From the above description it is apparent that the
platform 5 carrying the spindle heads 6 performs circular
3S and reciProcating motions relative to the working table 3
and that the spindle head 6 Performs reciprocating motion
2~7~G60 lO
relative to the platform 5 and the aorking ta~!e 3. It is
obvious that both spin,ile heads ~ can be provided with ~
mechanis~ for reciprocating motion. All said motions are
realized purely mechanically owin~ to the mechanisms 7.
For a better understanding of the operation of the
mechanism 7 and for illustrating the potentialities of the
milling machine of the invention, a description of some ad-
justments in setting said machine is given hereinbeloa.
As shoun in Fig. 5, the total eccentricity of the ec-
centrics 8, 10, adiusted by the worm-and-worm gear 20, 22,
is equal to zero, the radius of the crank 33, adjusted bY
the screa 34, is equal to zero, and the phase of the crank
33, adjusted by the worm-and-worm gear 31, 32, is equal to
zero. In this case, as shown in Fig. 6,-a~dot 57 is produced
on the workpiece 4, if the aorking table 3 is stationary,
and/or a longitudinal straight line 58 is produced .-,n the; aorkpiece ', if the wori;ing table 3 is in motion.
As shown in Fig. 7, the total eccentricity of the ec-
centrics 8, 10, adjusted by the worm-and-worm gear 20, 22,
is equal to zero, the radius of the crank 33, adjusted by
the screw 34, is maximum, the phase of the crank 33, adiust-
ed by the aorm-and-worm gear 31, 32, is equal to zero. In
this case, as shown in Fig. 8, a transverse straight line 59
~ . is produced on the workpiece 4, if the uorking table 3 is
: 25 stationary, whereas a sinusoid 60 is produced on the work-
piece 4, if the working table 3 is in motion.
As shoan in Fig. 9, the total eccentricity of the ec-
centrics 8, 10, adiusted by`the worm-and-worm gear 20, 22,
is maximu~, the radius of the crank 33, adjusted by the
screu 34, is equal to zero, and the Phase of the crank 33,
: adjusted by the worm-and-worm gear 31, 32, is equal to zero.
- In this case, as shown in Fig. 10, a circumference 61 is
- produced on the workpiece 4, if the working table 3 is sta-tionary, whereas a longitudinal cycloid-like line 62 is pro-
duced on the workpiece 4, if the working table 3 is in
motion.
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2076660 11
As shown in Fig. 11, the total eccentricity of the ec-
centrics 8, 10, adjusted by the ~orm-and-worm gear 20, 22,
is maximum, the radius of the crank 33, adjusted by the
screw 34, is equal to zero, and the phase of the crank 33,
S adjusted by the worm-and-worm gear 31, 32, is egual to zero.
In this case, as showr. in Fig. 12, an ellipse 63 with the
transversely disposed major diameter is Produced on the
aorkpiece 4, if the working table 3 is stationary, whereas
a longitudinal periodic parabola 64 is produced on the work-
piece 4, if the working table 3 is in motion.
As shown in Fig. 13, the total eccentricity of the ec-
centrics 8, 10, adjusted by the ~orm-and-~orm gear 20, 22,
is maximum, the radius of the crank 33, adjusted by the
screw 34,-is equal to zero, and the phase of the crank 33,
adjusted by the worm-and-worm gear 31, 32, is equal to 180~.
In this case, as sho~n in Fig. 14, an ellipse 85 ~ith the
longitudinally disposed major diameter is produced on the
workpiece 4, if the working table 3 is stationary, whereas
a longitudinal cycloid-like line 66 is produced on the work-
` 20 piece 4, if the working table 3 is in motion.
As shown in Fig. 15, the total eccentricity of the ec-
centrics 8, 10, adjusted by the worm-and-worm gear 20, 22,
is maximum, the radius of the crank 33, adjusted by the
screw 34, is maximum, and the phase of the crank 33,
adiusted
by the worm-and-worm gear 31, 32, is equal to 270. In this
case, as shown in Fig. 16, an ellipse 67 with inclined maior
diameter is produced on the workpiece 4, if the working
table 3 is stationary, whereas a longitudinal periodic para-
bola 68 with the pattern element inclined in the same direc-
tion is produced on the workpiece 4, if the working table 3
is in motion.
-~ As shown in Fig. 17, the total eccentricity of the ec-
centrics 8, 10, adjusted by the worm-and-worm gear 20, 22,
: 35 is maximum, the radius of the crank 33, adiusted by the
screw 3~, is maximum, and the phase of the crank 33, adjust-
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20766~0 12
ed by the worm-and-worm gear 31, 32, is equal to 90. In
this case, as shown in Fig. 18, an ellipse 69 with inclined
major diameter is produced on the r~orkpiece 4, iE the work-
ing table 3 is stationary, whereas a longitudinal Periodic
parabola 70 with the pattern elements inclined in the same
direction is produced on the workpiece 4, if the working
table 3 is in motion. The inclination of the ellipse and of
the elements of the periodic parabola in the present case is
opposite to that shown in Fig. 16.
; 10 As shown in Fig. 19, adiustments of the mechanism 7
correspond to those shown in Fig. 7, and, with the working
table 3 in motion, a sinusoid 71 is produced (Fig. 20). In
this version the cam surfaces 35, 36 and the carriers 37, 38
- -- participate in the work, as a-result of which the depth of
the pattern varies and a relief is formed. Version (a) in
Eig. 20 is obtained when the phase of setting the carrier 37
(38) is 0 (Fie. 19); version (b) is obtained when the phase
of -~etting the carrier 37 (38) is 90 (Fig. 19).
Described hereinabove are versions of the adjustments
with the parts of the mechanism 7 in extreme Positions. It
is obvious that the possibility of smooth variation of the
~utual positions of these parts in combination with the con-
ventional continuous or stepwise control of the speed of the
: drive 2 and also in combination with the conventional conti-
nuous or stepwise control of feeding the spindle heads pro-
vides a possibility of obtaining an infinite variety of pat-
terns on the workpiece 4.
From the description given .hereinabove it is obvious
that the milling machine according to the invention enables
the obtaining o~ most diverse combinations of the working
movements of the platform and the spindle heads, whereby an
infinite variety of patterns and reliefs can be produced
in a purely mechanical way.
Industrial Applicability
The present invention may find application in mechanic-
al engineerin~ in woodworking, and in other industries for
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207666~ 13
producing various slots, gtJoves, reliefs, patt;c!rls, and the
like. ~he nain applic~tion of the ~iiling ma hin~ ef the
present invention is the producin~ of re~uiari~ repeating
- pattern-. .
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