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Патент USA US2137099

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Nov. 15, 1938.
_ -H. SCHUSTER’
‘
2,137,099
METHOD OF MANUFACTURING CIRCULAR SHEET METAL DISKS
Filed Feb. 7, 1935
“in -*
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Inventor
54.42;.)
A ttomegs;
_
‘Patented
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UNITED‘, STATES P
warrior)
I
orv MANUFACTURING”
2,137,099-r
_
‘’ Hans‘I Schuster;
, SHEET
Inimigrath-on-the-LovVer-Rhlne
METAL msns
__
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-Germany
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Application ‘February 7, 1935“,,4SIefi-ia1_N‘
_
.IlnI IGermany‘December'15,“1ii34"'
. '6 Claims.
(01. 80-.4-416).
This invention relates to a, method of manu
facturing circular sheet-metal , disks 'by rolling
'li'ptical
thus,aftenitjhasjtheh
shape; Wh?i‘ihree
“ It‘ time
times" ceiv'ed'the‘eb‘
all thrqugh
45°,
and
each
‘time
fed'ftliroug‘h
‘rolls‘wwhich
pro
out a thicker disk of_ smaller diameter, such as
I is describedin myiformer United States patent duce a percentage reductior'i_“in-_thickness equal
:-5 application Serial Number 747,239. _ The pres ‘to that produced‘ghjIthe/I?rs "rolling ‘out step. "5 \
ent, application is a continuation'ih part of The ‘Work-piece- ‘new; has a‘ circular “shape with “
, a diameter greater vtlianjthelarger‘ ‘diameter of
said_formei'. and. cofpending application. 'I ,
I In the method described in my said former
the ellipse produced in‘"‘the', ?rst" instance; fl ‘
application, the work-piece is rolled out between‘ . Theoretically,.-Itne.. angle through which‘ the
11“ cylindrical rolls‘ in directions at ‘right. angles ’ Work-piece {has to lie turnedfe‘ach‘ .time'inorder 1°
‘converted’ ‘
_ to one another, inI'succession, the“ reduction‘ in to ‘enable the Tellipt" a1‘. shape to
I Ithickness_of_ each intermediate form,‘ which de
viates from the, circular shape,‘ being of the same
percentage, as the reduction'in thickness of [the
‘back into the circular ‘shape depends'zsolely ‘upon
the‘
of "repetitions v‘o'ffthe turning-opera
,tIion'Ithrough thisiangleIwithfdf course, the cor
'
‘Only angles smallerthan i5
‘:15 immediately preceding circular form from‘ which : responding ‘rollings‘.
it was: produced. According to my said former 90°, ‘however, are of practical importance‘ and. >
are ‘so, chosen‘ that‘ refformationv into the; circular
, application, the thickjcircular work-piece isre
mducedand expanded into an‘ elliptically shaped ,I shape is completedfafteronly a'few repetitions.
intermediate form by the ?rst'pa'ss, then turned If in ‘the "example just; referred to, an angle ‘of 20
I .20 through 90°_,..and rolled again, the rolls’ on the 30° hadbeen taken," then the work) piece would
second. pass, however, having a suitably narrower have to be‘ turned ?ve 'times',“i. e.__=altogether>
:Ipas'sa'ge. between them so that the same'per through an angle M1509, while withf-theassumed
centage reduction will bev produced as in the angle of 45° it ‘would'onlyjhave to‘be‘ turned three
‘previous rolling. In this 'mann'er'the ellipse is
,25 again converted into a 'disk of exact circular
. times through‘a ‘total angle{of-w135°.l~
I shape. The procedure can be, repeated as often
as desired. I
I
_
'
.
I
I
>
~
I
I
If circular hape, either 25
Starting‘
witli'a disk
originally or‘ as ‘produced by a ‘cycle of‘reducing 1.
operations wherein vaIIIgivenv angle of turning ‘was
employed, the ‘stool; maybe reduced in‘the-suc
o.
‘ , According‘ to an alternative'method of ‘opera
Ition,.the work-piece whichIhas become elliptical ' ceeding cycle by turning through-othervangles.
For example, itIthestock wa's'turned v‘through 30
I 30. after the ?rst p'assis turned through an angle
I‘ dif?ering from 90° vfor further ‘reduction in thick
‘ 'angl'es‘of 302145" or 'other‘small angles during a I
preceding 'cycle,1‘it may be'turned'l'through 90° I
or] some other‘, angle ‘on thefsucceedi'ng cycle. \
I ness'and reconversion into ‘the circular shape,
the‘operation of turning‘ the work-piece through
Or" instead offturning eachr'ti'me inf 1a.v cycle I
' this angle with accompanying ‘ further rolling
through equal angles, the stock ‘may be turned 35
35 out being repeated until the minor axis of the
through 1a givenlangle or angles and finally
ellipsefhas become equaIl'to the ‘major ‘axis, that
through anfan'gle which is supplementary to the
is tovsay, untilI'Ithe circular shape has again been
attained. This method, as inthe case of 'the previous angle of turning._ ' By ‘employing sup
plementing anglesI at‘ the en'dtoizrthe ,l-cyjcle the
I_method of 'myfformer application, can be re
, 40 peat'ed'as often as‘desired.‘ ‘This rolling-out" of conversion‘ back to"circular_*formimay“ be has-. 40.
the work-piece in di?erent radial directions ' tened‘." However, "in~'any~plan‘of‘operation the.
angles of turnln'gIIjImust-bei carefully selected
I. may under certain circumstances have a favor according
whichtI have-discovered‘
If,__able actiononthe texture of the ?nished disk, “ and ' whichtoj'the'law
will" be more ‘fully stated hereinafter.
"particularly ‘when the rolling“ is carried out in
"*jAgainft-he percentage of reduction for-each 45
\ I j IIItne'
"possible
{coldand‘
.state?gi-iot
may, I under
rolling
someis;
circumstances;
‘of course‘, also
be i v"pass-1n ‘a cycle may-also be varied if the herein.
“.,Ipreferable’.
I_
’ disclosed law of‘i‘eduction is ‘followed...
iI , '
In accord ncéfthen,
the ‘second method“
The angle'ot v‘urning,\the percentage‘of reduc
I Iv‘offoperation', the thick simmer initialwork-piece _' - tion, and the" number ‘of .passes ‘in - a cycle from
shape toécir'cular shape may be ascer-' 50
, 5‘o‘uis-?rstrolledI out to al?e?nitemeducedthick-Q ‘circular
- ‘ ness and the 'ellipse'thus "iIQrm‘ed‘liasI its v'major ’ "tained either graphically or mathematically or
"axisiat‘ri‘ght' angles‘ to the ‘axes ‘of?the"rolls;' ‘it is"? .'
.
by-:bothfmethods‘v-combined . in , accordance with
hereinldisclosedlawn 7." i
""then‘turne'dfthrough an. angle of (forexamplé) »“ "the
I
abouti45°jand inf-thisepositionr'isfed "through? '1 , It-is .self evident-that theater angle'throiigh
.
I 55' rolls;_the passage‘ between which? is so dimen-"s lwhich the work hasto be turned for converting 55
‘
sionedthat the. same-‘percentage reduction in}. " “to the circular shape from‘ the elliptical shape
thickness (25 per cent, for example) is e?ected will be smaller the nearer the angle of turning.
for one pass approaches 90°. In the
of
as is the case in the preceding pass. Thispro
cedure is then twice repeated in' case the tum-_ angles which approach 0°, there ?rst of all
a0 ingangle, as assumed, is 45°. The work-piece is, >Itakes,_ place an increase in the deviation from. w‘ ‘
2,187,099
the circular shape followed later by an ap
proach and evening out to the circular shape.
But such initial increase in the deviation from
circular shape I ?nd is a drawback and may
be avoided if an angle is employed which lies in
the neighborhood of 45° or over. Otherwise.
that ‘angle is to be preferred by the use of which
the smallest possible total angle of rotation will
represent a multiple of this angle without re
10 mainder, such as in the cases of the angles of
45° and 30° given by way of example. In. the
case of a great many angles, the smallest possi
ble total angle must be exceeded by ‘further
repetition if theotherwise remaining fraction. is
small angle of rotation is di?erent from that in
the case of a larger angle of rotation.
This
requires a correction to the calculated supple
menting angle which would ordinarily, in prac
tice, be determined empirically although un
doubtedly it could also be ascertained by cal
culation.
1
Since at such- repetition of the turning opera
tion and corresponding reduction in thickness, an
increase in the size of the work-piece in the 10
directions of-both axes of the ellipse takes place,
and since we are only concerned with the ob
taining of a larger and thinner ?nal disk, it is
~ not always necessary to effect a pass with a
15 not to be ?lled up by a supplementing angle of a
supplementing angle in order to reduce the num
di?‘erent number of degrees which then has'to
be ascertained while taking into consideration
ber of_ passes.‘ Thus, in such cases where a par
the necessary reduction in thickness.
'
In the accompanying drawing which illustrates
Fig. 1 illustrates a rolling mill for reducing"
the stock when the turning betweenrolling op
the turning angle is 45° and where in each
pass the percentage reduction in thickness is 25
e per cent.
Referring to Fig. 1 of the drawing, a circular
30 disk of stock A is passed between the two upper
.rolls B andG of a three-high rolling mill to
produce the elliptical shape E.
,
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I
It is worthy of mention that there. is still a
Figure 2 illustrates the successive stages of
Thiselliptical
shape is now turned through 90° and passed
between the lower rolls C and D to .produce the
exact circular shape F.
can be chosen instead of the interposition of a
supplementing angle.
_
25 the reconversion of the ellipse to a. circle where
35
duce a-circular shape after numerous repeti
tions of. the turning operation, this repetition 20
20 practical applications of the invention:
erations is 90°; and
ticular angle of turning alone enables a total
angle of rotation to be attained which will pro
.
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further possibility.‘ The ellipse produced in the
?rst instance by turning the work-piece through 25
any desired angle and subsequently reducing it
in thicknex by rolling, can first of all be con
verted into another ellipse, angularly displaced
and of greater area, the work-piece being then
so turned that the major axis of the ellipse 80
lies ~parallel to the rolls and rolled out in this
position with a. di?erent percentage reduction
in thickness, the extension ‘taking place in a.‘
direction at 90° with respect to the major axis
as in my former patent application above men
Referring to Fig. 2, i is the initial ellipse which
has been produced by rolling out the circular
work-piece indicated by broken lines; 2 is the
tioned. The altered percentage reduction in
thickness must be so proportioned that ‘a cir
cular shape now results from the ellipse which
intermediate stage, also elliptical, which results ‘ was altered with‘ respect to the original ellipse.
after the work-piece has been turned through According to‘ the size of the preceding angle of
45°; 3 is the further elliptical intermediate stage,
rotation the percentage reduction, in thickness
and 4 is the ?nally obtained circular shape. The
must be greater or less; that is to say, if the pre
intermediate elliptical shapesare angularly dis _ceding angle of rotation was 45° it would have
placed with respect to the immediately preced-~ to be smaller than in the case of a preceding
ing shape. The successive turnings of the work-
angle of rotation of 30°.
piece through 45° are to be understood as mean
ing that the elliptical work-piece taken ‘from
the preceding pass is so introduced between the
succeeding pair of rolls that the major axis
50 of the ellipse is- turned through‘ 45°. with respect
to the direction of rolling, whereupon after this
pass the work-piece is then- again'turned through
a further 45° with respect to the direction of
rolling so that it has ?nally been turned with
respect to the direction of rolling through 135".
.
It is to be noted as one of the features of the
invention that the ?nal working. to circular shape‘
is attained by rollingthe elliptical work piece
at 90° to its major axis. that is, in the direc
tion of its minor, axis. The amount of working
requiredcan readily be calculated in relation
to the previous amount of working in the pro
portion of the angle turned to the total turning '
of the previous angle or angles.
In any case where it is desired to produce a 55
The major axis of the last ellipse however, as' circular disk having de?nite diameter and de?
can be seen'from the drawing, has. only been ‘nite thickness, when the precise treatment has
angularly displaced, with respect to the direction been determined, one may ,ascertain‘by graphi
of rolling, through an angle-0145“.
'
cal or empirical preparatory work, or even pure
‘so The supplementing‘ angle .above referred to: ly by calculation backwards, what dimensions 60
cannot always be ascertained with exactness by the initial work-piece must have. If the case
a simple calculation. Take the case, ‘for ex
occurs where theparticular position of the work
ample, where an angle of 11°, with a three times piece in the intermediate stages has to-be a's-.
repetition, almost produces the circular shape, certained with respect to the roll axes and the
dimensions of the ellipse of'the individual inter 65
65 which for its complete formation requires a to
tal angle of 11° which is somewhat greater than mediate shapes, then this can be facilitated by
311°. By simple calculation, if one reckons from making the determination necessary to provide
the ?rst ellipse, a supplementing‘ angle of‘ that the major axis of the particular ellipse to
70
b°—-3a must be chosen for the fourth pass. But _ be rolled shall extend in the direction of the
this would not be rigorously‘ correct in every "bisector oi' the turning angle and that the magni 70
case since it has-been ascertained that ,_f_or__.al-v tude of the ratios between the major and the
tering the ratio between thetwo-axes of the ~minor‘axis of the respective ellipse can beset
I ellipse, the position‘ ‘or theangle bisectorsfwith;
respect to the’rollin'g axis has torbev taken ‘into’
70 account, which inthe caseoi’. acoi'nparatively
f down as ordinates on a sine curve.
_,
'
in the case of ‘my former patent applica
tion, the initial work-piece is preferably ob 75
3
2,137,099
tained by the reduction of a cylindrical block.
If value is not attached to th'e‘obtaining of
an exact circle as ?nal shape, that is to say, if
an approximation to the circular shape Su?ices
and the exact circular shape is- intended to be
obtained by another further treatment, e. g. by
cutting, then, of course, the described process can
v To summarize what has been statedand illus
trated by example hereinabove, the rule or law
may be stated as follow: 1
Starting with a circular disk of uniform'thick- .
ness, the stock is rolled a number of times in
a cycle to change it from circular shape to G1
liptical shape and then back into exact circular
be terminated as soon as an ellipse is produced
shape.
I
v
'
The percentage of reduction and the principal
which does not depart excessively from the circu
axes of the ellipse formed in the ?rst operation 10
in the cycle, or ?rst change from circular to el
lar shape. In cases where the ?nished article is
required to be of elliptical shape the process
would, of course, not be continued until the cir
cular shape were restored but would be termi
nated on the obtainment of the desired ellipti?
cal shape with the desired dimensions.
As already stated in my former patent appli
cation, a thick‘disk of elliptical shape can be
employed as the initial work-piece and further '
liptical shape, are takenas reference or datum
points upon which subsequent operations in the
cycle are based.
I
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The stock is worked in a straight line across 15
its width. that is, along a diameter or axis,
whether the operation is a continuous rolling
action or otherwise.
In any cycle from circular
operated upon accordingly until the desired cir-l to-circular it is to be understood that the char
20 cular metal sheet or elliptical metal sheet hav
acteristics of the operating means, so far as side
spread of stock is concerned, remain unchanged,
ing the desired dimensions is obtained.
Furthermore, when employing an angle of
or if changed that due account thereof be taken.
rotation which di?ers from 90°, the work-piece
In any given cycle from circular-to-circular,
is operated upon in various radial directions, and the increment in length along one principal axis
.25 not merely in two directions at right angles to v of the ?rst ellipse is made equal to the incre
one another, whereby the texture of the metal I ment in length along the other principal axis.
The. last operation in the cycle from circular
_ is improved. Moreover, the' angle of rotation
to-circular is effected along the minor axis of
differing from 90° can be also utilized to obtain
?nal forms which di?er both from the circular
30 shape and from the elliptical-shape; for by em
ploying in the course of the process angles of
the last elliptical shape.
rotation of diiferent size so that the reduction
in thickness in the course of the process varies
turning operations.
in percentage, not only the dimensions but also
particularlygif in addition an- initial work-piece
is chosen which also deviates from the otherwise
circular or elliptical shape.‘ ‘By graphical crem
pirical means which may also‘ be assisted in part ‘
desired dimensions which may be required at any
particular time and for which the initial shape
-
.
The percentage of reduction at‘ each rolling
operation is preferably made an aliquot part or
simple multiple of the degree of reduction in the 35
35 the shape of the ?nal form can be in?uenced,
40 by calculation, it is possible in very many cases,
in this manner, to obtain a ?nal form of the
,
The change from circular shape to circular 30
shape is preferably e?ected in a few reducing and
?rst rolling operation from circular.
This, of
course. includes the case Where the subsequent
reduction is equal to the ?rst, that is, a unit mul
tiple of the ?rst.
The angle of turning for each rolling opera 40
tion is preferably made} an aliquot part of 90°
or of a simple multiple of 90°, such as 180° or
270°, usually-not over 180°. The angle of turn
with its dimensions, as well as the shapes and - ingwill be 90° or less, 'i. e. an acute angle, since
45 dimensions at the individual steps of the proc _ the effect of turning more than 90” is the same 45
ess including the. necessary angles of rotation as turning less. For example, the effect of turn
and percentage reductions in thickness, can be ing 135° obviously‘ would be the same as turn-1
ascertained.
It has previously been proposed, for example.
50 in the patent to Milliken No.- 1,561,346, Novem- >
ber '10, 1925, to roll circular disksinto elliptical
shape and then turn them through 90° and roll
them again with the idea of again producing a
circular shape. However, no rule of working is
55 given which will assure the return to circular
shape. One mustexperiment to determine the
degree of reduction, required to restore the el
liptical disk to circular, shape. Of course, ‘it has
long been known, even inthe simple arts of roll
60
ing dough, putty, modeling clay and the like,
that an elliptical shape could be restored to an
approximately circularshape by rolling the el.
liptical shape‘along its minor axis. But these
known methods are experimental and give no
65 de?nite assurance of producing‘an exact circular
shape; moreover they refer only to the simple
case of turning through. 90° and furnish no
‘ assistance when the ‘stock is turned through
angles other than 90°.
70
According to the‘ present invention the altera
tions in the diskare performed under a rule or
ing 45°, and of turning 150° the same as turn- ‘
ing
30°.
.
-.
.
When. turning by the same angle for each 50
reduction in the cycle,v the total number of re- .
ducing operations required will bethe quotient
of 90° divided by'half the angle of turning. For
example‘ the number of operations when turning
90° will be 2; ‘for 45°‘the number will be .4; for :
30° the number will be 6; for 60‘’_ the number
will be 3; and so on.
The total angle of‘turn
ing from circular-‘to-circular will be the hum-'
ber of operations, minus one, multiplied by the
angle of turning. ' For example, when'turning
90° the total angle will be (2-1)'><90° or 90°;
when turning 45° ‘ the ‘total angle will be‘
(4+1) ><45°-or 135°;‘when turning 30° the‘total
angle will be .(6—1)><30° or 150°;when turning
60° the totalangle of turning will be
or 120°; and so on.
-
When turning through ‘angles which‘ are not
simple aliquot parts ofj90° or'of a simple multi- '
. pie‘ thereof and when turning through-supple»
menting angles to ha‘stennthef return to-c'ireue'
lar shape, the basic‘ rules are adhered'tofnameé
"law which will de?nitely assure the return to 1y, that the last reduction is along the minor axis
exact circular shape when that is desired, re ' of the last ellipse and that the projected incre~
gardless of whether the stock is turned through ments in reduction along the two principal axes
of the ?rst ellipse‘are made equal.
75
75 an angle of 90°>or any other angle.
4‘
2, 187,099
When reducing in any turned position by per
centages " different from the percentage of re
duction at the ?rst operation, the basic rules are
observed, namely that the last reduction is ef
fected along the minor axis of the last ellipse, and
thepercentages of reduction along the two prin
cipal axes of the ?rst ellipse are made equal.
If one of the other regular forms produced in
the cycle is desired instead of the circular form,
angle which bears a. low-simple relation to one
of the quarters of a circle, namely, 90, 180, 270,
360 degrees; rolling the disk along the new axis
to reduce its thickness by the same percentage
as at the ?rst action; repeating'the turning and
rolling after the ?rst, said rolling action until
the disk is made substantially truly circular on
the ?rst approach to circular shape, that is, un
til the minor‘ axis of the ?rst vellipse becomes
10 the operations may be stopped with the desired equalto‘the major axis; and continuing the op 10
form instead of being continued to produce the . erations until the disk has the ?nal‘ size and
,
circular form. For any other shape, the nearest _ thickness desired.
duce accurate predetermined circular shapes by
4. The method of - manufacturing disks of mal
leable-material, which comprises, rolling a cir
cular disk along a ?rst axis to thin it by a 16
given percentage and to change it to a ?rst el
liptical shape; turning the disk through one of
the angles 15, 30, 45, 60, 90 degrees; rolling the _
a plurality of reducing and turning operations
disk along the new axis to reduce its thickness
regular shape is taken and changed as required
to produce the desired shape.
_
It will thus be seen that the invention provides
a simple practicable and dependable method of
reducing disk stock in such manner as to pro
of different angles. This is possible because the
by the same percentage as at the ?rst action; 20
repeating the turning and rolling after the ?rst
invention furnishes a dependable rule or law by
said rolling action until the disk is made sub
20 in which the turning may be through a number
which to operate.
vWhile certain embodiments of the invention
25 have been described it is to beunderstood that
the invention may have various embodiments
within the limits of the prior art and the scope
of the subjoined claims.
‘
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stantially truly circular on the ?rst approach
to circular shape, that is, until the minor axis
of the ?rst ellipse becomes equal to the major
axis; and continuing the operations until the
disk has the ?nal. size and thickness desired.
5. The method of manufacturing disks of
It is, however, an essential condition that the
malleable material, which comprises, rolling a
30 work-piece is not only turned but is, besides,
circular disk along a ?rst axis to thin it by a
given percentage and to change it to a ?rst el
of become progressively narrower by the same
liptical shape, turning the disk through one of
the angles 15, 30, 45, 60, 90 degrees; rolling the
passed through pairs of rolls, the passes where
percentage, provided, that particular reasons do
not give rise to a change‘ of the rule regulat
35 ing the decrease of the thickness of the sheet
- metal, as has already been pointed out in the
preceding pages and in which cases the width
of said passes is otherwise regulated according
to the change of the said rule.
' I claim:
l\. The method of manufacturing sheet metal
disks by rolling out a disk between cylindrical
rolls, comprising ?rst rolling a circular disk
work-piece into elliptical shape and then re
peatedly turning it through an angle of which
90° is a multiple and further rolling it to reduce
its thickness until' a circular shape is again
obtained, each successive pass of the work-piece
between the rolls, after, the ?rst pass, being so
determined that the reduction in thickness pro
ducedthcreby will be of the same percentage as
that of the ?rst.
2. The method of manufacturing sheet-metal
disks which comprises ?rst rolling out a thick
er circular disk of smaller diameter between
cylindrical rolls whereby the work-piece is ?rst
reduced in thickness and changed into an el
liptical shape, then repeatedly turning the work
piece and rolling it further to reduce it until it
again becomes exactly circular, each turning be
ing through the same angle of which 90° is a
multiple and the width of the successive roll
passes being so adjusted that the reduction in
thickness obtained with each rolling with re
peated turning through the same angle is of the
same percentage as the reduction produced by
. the ?rst rolling. '
3. The method of manufacturing disks 01' mal
leable’ material, which comprises, rolling affir
disk along the new axis to reduce its thickness
by the same percentage as at the ?rst action;
and repeating the turning and rolling after the
?rst‘ said‘ rolling action until the total number
of rollings along different axes, including the
?rst, equals the quotient obtained by dividing 90
degrees by halfthe angle of turning; the total 40
angle of turning being equal to the total number
of rollings, minus one, multiplied by the angle
of turning, whereby-the disk is made substan
tially truly circular by making the minor axis
of the ?rst said ellipse equal to the major axis 45
thereof before further rolling operations are
performed on the disk, for the purposes set
forth.
'
6. The method of manufacturing disks of
malleable material, which comprises, rolling a
circular disk along a ?rst axis to thin it by a
given percentage andto change it to a ?rst el
liptical shape; turning the disk through one of
the angles 15, 30, 45, 60, 90, degrees; rolling the
disk along the new. ‘axis to reduce its thickness
by the same percentage as at the ?rst action;
and repeating .the turning and rolling after the
?rst said rolling action until the total number
of rollings along different axes, including the
?rst, equals the quotient obtained by dividing
90 degrees by half the angle of turning; the to
tal angle of turning being equal‘to the total
number of rollings, minus one, multiplied by the _
angle of turning, and the last rolling to return
the disk to circular shape being effected along
the minor axis of the last formed ellipse, where
-by the disk is made substantially truly circu
lar by making the minor axis of the ?rst said
ellipse equal to the major axis thereof before
cular disk along a ?rst axis to thin it by a ' further rolling operations are performed on the 70
disk, for the purposes set forth.
70 given percentage and to change it to a ?rst el
liptical shape; turning the disk through an
HANS SCHUSTER.
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