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Патент USA US2411801

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Nov. 26, 1946.
2,411,801
J. S. NIELSEN ETAL
METAL BENDING AND STRETCHING APPARATUS
‘ Filed Sept. 1i, 1943
3 Sheets-Sheet 1
_1. 5.‘k
.james 6. Nie/51221K»
~Nov. 26, 1946.
l
J. s. NlELsEN ETAL
2,411,801 '
METAL BENDING AND STRETCHING ÁPPARATUS
Filed Sept. 11, 1943
Sheets-Sheet 2
2,411,801
Patented Nov. 26, _1946
UNirîeo STATES PATENT OFFICE
METAL BENDING AND STRETCHIÑG . `
~
»
APPARATUS
,Y ' 'rames s. Nielsen, Stow, ana Clyde B. Machala,
Akron, 0hio,- assìgnors to Goodyear Aircraft
Akron, Ohio, a corporation of
~ Corporation,
Delaware
Application september 11, 1943,*seria1na‘501p16 f
13 Claims.
1
This invention Yrelates to 'metal stretching and
bending apparatus, and, vin particular, to an ap
paratus for forming straight bar material of metal
and the like of any cross Sectional conñguration
into smooth contours of predetermined shape by
stretching the stock material and at the same time
(Cl. 153-40)>
2
or sheet metal bars >around a revolvable‘form block
without spring back.
Another` object of the invention is to provide
apparatus for forming metal, or like material,
-» around a form block over van angle of more than
about 180 degrees.
Another object of the invention'is the provision
Winding it around a forming die.
‘
of
compact apparatus of the type described and
' Machines are known on which a tube or the like
which> is relatively inexpensive to build and to
is bent without stretchingaround a die. How'
maintain, long wearing and easily operated in use
ever, in this case a male and a female die are re
with
a minimum of readilytrained personnel, and
quired to avoid wrinkling of the material and the
which rapidly and efficiently turns out high grade
rather expensive die does not give satisfactory re
and uniform work.
sults without- compensating the die for spring
Another object of the invention is to provide
back of the material.
`
apparatus
of the character described and operable
15
Other'machines are known which apply stretch
solely with a iluid pressure motor.
`
ing while bending oi the work piece takes place.
Another object of the invention is the provision
However, machines of this type, although produc
of a modification of the apparatus wherein the
ing satisfactory'work ori-some sectionsand sizes,
sprocket and chain assembly need not be em
are bulky and heavy in construction, require a
.
large space‘and considerable personnel, and are at ployed.>
Another
object
of
the
invention
is
the provision
not adapted'f or bending through an angle of more
of
a
sectional
or
multi-part
die
for
forming
metal
than 180 degrees, but usually operate to through
substantially without spring back.
angles or" much less than '1189 degrees.
Other objects of the invention will appear as
4The! present invention avoids theA shortcomings è5 the description proceeds.
of these >known constructions by a novel arrange
ment whereby the stock material is stretched
and at the same time is Wound around a form
For a better understanding of the Y invention
reference should be had to the accompanying
drawings wherein:
f
block or die secured to a turntable. The stretch
- Figure 1 is a topplan View of o-ne embodiment of
ing means, usually a hydraulic cylinder, is vat
invention showing a work piece in the ma
tached to an endless‘chain which passes'around ai the
chine after a, completed bending operation;
a sprocket secured to the turntable at one end and
Figure 2 is a front elevation of the apparatus of
an idler sprocket mounted at the opposite end of
Y Figure 1 with the front supports broken away for a
the Work table. y As the table rotates, the cylinder
better showing of the driving mechanism ofthe
moves toward the turntable, at exactly the same
'i machine;
.
lineal' speed- as the periphery of the sprocket.'
Figure 3 is a fractional section through the table
' ' Twofpneuma-tically operated jaws are employed
to hold` the stock, one jaw being fastened tothe
piston rod of the'cylinder and one jaw being se- p
cured to the turntable adjacent theform block.
The construction of the apparatus is such that a
constant -or controlled -tensile force is exerted on
the Ypart during the entire vforn'iing operation.
Owingrto the fact that the distance fromïform'
block contour to the center of theturntable may
vary, the circumferential speed of «the form die
usually differs' from the speedof the hydraulicA
cylinder. " This' diiierenc'e'is compensated for by
the movement vof the'fpiston in" its cylinder, thus>
always securingthe necessary ¿tension inthe' work
on line IIT-IIIfof Figure 2;
K
'
Figure 4 is a diagrammatic plan view'illustrat-l
ing the manner in whichthe apparatus of Figures
1 to 3 can ber operated without a motor.
«Figure 5 isla diagrammatic` plan View of a mf'idi-~.y
neat-ion of the apparatus of> Figures 1 to'3;
Figure/6` is a plan lView 0f a multi-part form
ing die;
'
_
Y
'
Figure 7 is a'sectional view taken onerline VïI
VÍI of -Figure 6;
f
Figure 8 is a sectional view taken on line VIEI
VIII of Figure 6.
' »
'
~
The apparatus of the invention in oneL best
piece.>`4 The finishedflarticle thus formed on this 50 known embodiment consists of a table, indicated
as a whole bythe numeral lâ, and including sup
machine has fa smooth surface vfree from wrinklesr`
ports l2 to which is secured a top I4 at the ends
and conforms perfectly to the shape of the form'
die with practically no spring back. Y
The main object ’ciA this inventionv isl the pro
of 4which are mounted vertical shafts IB and I8
in bearings 20, 22 and 24,- 26, respectively. The
vision of apparatusîfor formingr rolled, extruded 55 _bearings 2li and 24 are fastened to the table top
2,411,801
3
and the bearings 24 and 26 to transverse channels
23 connecting the table supports. To each one
4
and requires only a single operator. 'Í'o make
, the machine ready for operation the turntable 34
of the shafts It and I3 just beneath the top of
the table is keyed a sprocket 3@ which sprockets
are connected by an endless chain 32. The shaft
|8, which extends through and above the top of
the table, carries at its upper end a- turntable or
die support 34 provided with anchor Vslots 36. The
is rotated to position the gripping devices ‘I6
and £28 in alignment and a distance apart about
equal to the length of the work piece. The work
piece then is inserted in one pair of jaws and
then in the other pair of »jaws by moving the
piston 'I2 back or forth, as the case may be, by
shaft IS is preferably driven, usually by an elec
supplying controlled amounts of ñuid thereto from
tric reversible motor 38 of the variable or multi 10 the pump iv2il. With the forming die and its
speed type, and operates a reduction gear box 48
supporting block rvlocked against relative move
located underneath the table.
_
_
In the chain 32 is inserted a special adjustable
link 5E] to which is attached, by bolts 52, a slide
ment, the turntable is put in motion by opera
tion of the motor 38 and the work piece W is
brought under suñicient tension by the controlled
or cross head 54 consisting of bottom and top 15 flow of fluid to the cylinder 10 to permanently
parts 5t and :18 connected by bolts 60 and slid
stretch the material the desired amount. The
able in a slot B2 in the table top I4. In the upper
stretching of the work piece prevents wrinkling
part 58 of the slide is a, fixed pivot stud 62 about
of the material during the bending process. The
which is rotatable a support 66. To prevent eX
pivotal mounting of the power cylinder support
cessive tipping stress on the stud 62 the support 20 results in the stretching force being applied to
66 is held against the upper slide part 58 by one
the work piece in a direction which is always tan
or more gib fingers 68.
gent to the circumference of the forming die.
To the support G5 is bolted in a vertically ad
The tension on the work piece, and, accordingly,
justable manner a hydraulic power cylinder 10
the permanent stretch thereof may be regulated
which furnishes the power for stretching the work 25 during the bending operation to obtain the best
material W. The cylinder lo includes a piston
results and a perfectly smooth article Without
'r2 having a hollow piston rod 'i4 which carries
any spring back. In many cases,l however, the
at one end a gripping device ‘it having movable
tensio-n or stretch applied can be kept constant
jaws 86. The side of the piston opposite the
during the bending process.
rod 'F4 is provided with a hollow rod extension 30
In cases where the bending angle on the work
îS to the end of which is attached a bracket 80
piece is obtuse or not smaller than 90 degrees
supporting a small pneumatic cylinder 82 having
and the bending radius not too small the die can
a piston rod 534 which extends slidably through
remain fixed to its support without resulting in
the hollow bore of the extension 28 and rod 14
spring back. However, in c'ases where the turn
to operate the jaws 86 in the gripping device 1B. 35 table is rotated through more than a right angle
Another gripping device 88 is adjustably mount
to bend the work piece to less than a right angle,
ed o-n the turntable 34 by clamps Sii. This de
and particularly when the work piece is bent
vice also is provided with a small pneumatic
around a small radius, itis very advantageous
cylinder 92 operating jaws 86a by which the end
to make the die swingable while or after the
of the work piece W is held while being stretched 40 bending is performed. One manner of achieving
and bent over a form die It@ mounted on the
the swinging of the die is to position it so that
table.
the slot ||2 is on the side of the bolt opposite
It will be understood that the work W is`
from that shown in Figure 1. The die is then
stretched between the gripping devices V'i6 >and
fastened on the block suñiciently tight to permit
83 as it is bent around. the form die IDG which a some slippage so that when the turntable rotates
is adjustably mounted on the turntable 34. More
the friction between the work piece and the die
particularly, the die ità) may take a wide variety
will tend to and will turn the die.
of shapes, sizes or constructions, but in the form
Another, and usually a preferred way of op
illustrated it is made of two pieces |32 and |04
erating the pivoted part die, is to complete or
bolted together and which in assembled comple 50 substantially complete the bending of the work
mentary relation form a curved groove into which
piece and the rotation of the turntable before re
a portion of the work piece W slidably fits. IThe
moving the locking p_in. Thereafter, the locking
forming die mi) is either ñxedly or swingably
pin is removed and the work piece is given a ñnal
mounted by two bolts |85 and |68 to a block ||il
stretch accompanied by a rocking of the pivoted
which in turn is fastened to the turntable 34 by 55 part of the die. The important feature in this
clamps QG. The forming die when it is made
operation is that the ñnal and setting stretch
swingable about the bolt ißt is (as is usually the
thereby imparted to the work piece is not con
case when material is to be bent through an
centrated at one end of the Work piece (as is
arc approaching 180 degrees) provided with an
the casewhere the friction between the die and
arcuate slot | l2 of suitable length through which
the work piece of a fixed die prevents the pull
passes the bolt |86 thereby forming a stop tothe
on one end of the work piece from being trans
-arcuate movement of the die in either direction.
mitted to the other end thereof), but is applied
Provision is also made for fixing the relative
equally `toboth ends of the work piece by the
position of the die and its supporting block by
rocking of the die.
n
placing the hole ||\B in the die over the hole ||8 65
In vthe operation of the ,apparatus it will be`
in the block and by inserting a locking pin
understood that as the work piece is bent around
therein.
,
the die block the sprocket and chain drive moves
For supplying the hydraulic cylinders with fluid
the support for the hydraulic cylinder towards
under pressure and to make the apparatus in
the die block whereby only aA relatively short
dependent of available ñuid pressure lines, a 70 hydraulic cylinderis required as distinguished
pump |26 is ordinarily provided which is driven
from a long awkward cylinder which might
by an electric motor |22 and with the pump
otherwise have been necessary. Further, hy
being fed from a service tank |24 to which the
draulic control of the tension and piston move
ñuid, usually oil,vreturns.
.
ment in the cylinder is facilitated particularly
The operation ofthe machine is very simple 75 where the die block is positioned on the turn
2,411,861
'5
,
most conveniently employed in conjunction with~
table so as to have about the same radius as the
turning sprocket.
a particular die block, such as Vindicated at'lllilb,v
which when positioned as 'shown on turntable 342)
can be turned by the turntable to wrap the rWork
`
It will be noted `that with the apparatus of the
present invention work pieces can bebent into
complexer compound curves and through angles
of upto or even greater than 360 degrees.
piece around it, all vwithout appreciably changing
the ¿position of the piston in a iiXed .hydraulic
The
cylinder 'lâh but which is'free to turnabout a
apparatusfrequires Aonly the> very simplest kind
vertical pivot.
or" , die block constructions.
'
'
In this embodiment of the invention thetnrn
Although the drawings arev shown `with only
one turntable as a form die support, the'` invention 10 table- 34h 'must be rotated by positive turning and.
bending means, andthe entire kapparatus may
contemplates providingira 'pair` of turntables, one
_tal-:e the form of a Vseparate machine having a
on yeach vertical shaft and av hydraulic cylinder _
~ somewhat longer hydraulic cylinder to take care
associated with each stretch of the chain 32 ex
of any discrepancies in the windup of the work
piece. On the otherhand, lthe apparatus ‘of ~iï‘ig
tending around the sprockets Í35.'. rlîhus„a second
setof rstretching and bending devices is provided
opposite the'one shown, thereby doublingthe pro
ductive capacity of the machine without increas
ures 1 to 3 may be modiñed to have a stationary
pivot _post or hole to which the hydraulic cylinder
can vbe movedÍ for operations uponcertain work
~
'
pieces and .dieblocks.,
~
a
«
From the description it will be recognized that
Figures 6, 7 and S kshow a modiiication of the
the present invention is a decided` improvement
die block‘oi the preceding iìgures of the draw-r
over previous constructions oi stretch-bending
ings. More specifically, in the embodiment of
machines in that its output is of the highest qual
the invention of Figures l to 3 the entire die
ity and perfection in smoothness as well asin
block is made movable, whereas Figures 4 and 5
shape and withspring back substantially elimi
show stationary die blocks. In Figures 5, *l
8
nated. The articles made by the improved appa 25' part
of the die block isrigid and Vpart is movable.>
ratus and by a minimum of ordinary personnel
It should be understood,=of course, that the var
can be produced inexpensively, rapidly, and with
ious die >blocks are interchangeable on the several
little waste oi material. Besides, the space re
forms of the invention shown, the use of any
quired for the improved apparatus is smaller and
particular block being dependent upon thepar
its cost lower than that of machines for similar 30
ticular shape to be formed of the-work piece, all
ing its size. .
purposes.
'
as already explained heretoiore.-
- Turning now to Figure 4 of the drawings, there
tion of the improved apparatus wherein operation
ñxedly secured b-y clamps 2id a pillow' 2li?. . The
is achieved: without an electric motor 38 or other
means »for rotating the turntable; More particu
l'arly,A it is entirely possible and permissible to
employ the hydraulic cylinder l@ of the apparatus
to-achieve both stretching and bending of the
workpiece. This'result can be accomplished, in 40
the inodiñcation of the invention illustrated, in
asmuchas» the hydraulic cylinder _iba vhas lits pis
ton rod `connected to therv work ïpieceïWa, ‘as
already described, with'the work piece ‘extending
around a. die block idea; The pulling force on
the Work piece Wd is transmitted'through the
~
pillow has a multipart die ‘block 215, 2 i8 mounted
thereon, the part 216 being rigidly fastened to
the pillow and the part 218 being .,pivotally
mounted as shown -with'a stud bolt 22d. -Each
part of :the die block. in the form shown to pro
ducela curved channel is conveniently made up'
of relatively thin plates mounted top and bottom
of the main dieblock and with the thinv plates
bein'ggrooved :to receive the side flanges of the
channel workpiece being formed. ’The turntable
2li? is-r’irovi'dedl with a clamp 22e to receive the
VAendy lor“ the work piece.
cylinder'ldd to the chain 32a, as before described
with respect to Figures 1 to 3, and thence to the
sprocket 36a and the turntable 34a.
'
In Figures 6 to 8, the numeral 2li) indicates
generally a turntable to whichv is adjustably b-ut
has been diagrammatically illustrated a modifica
’i In fthe ¿operation of:'the
apparatus, and with
the parts in lthefdotted'line position shown, the
Y ~ `
50 turntable is'rotated in a clockwise direction to
Accordingly, the turning moment on the turn
table 36a is equal kto the stretching` tension put
into the work piece "multiplied vby the sprocket
radius R2, minus _the stretching tension multi
pliedeby the radiusk Rl from the centeror" the 55
turntable-'to the tangent ofthe die "block,A minus
theìmoment duev to irictional resistance.. Inotherv
move vthe die block to the 'solid line position
shown.`> During the associated bending and
stretching operation the movable segment ‘lla of
the-die may be left free to move or it may be held
against movement until »near the end of the oper
ation, _all as already described in conjunction
wordsi-ïas long as the radiusoithe" chain-'sprocket
3Go is somewhat greater »than ïthe‘radius oi 'the
die block :leed mOunteà-i’nh‘the turntable, any
with the apparatus of Figures i to 3.
In any
worklpiece ¿We willY also result >inïfa‘rotation ofv
the- turntable toi-bend or wind the workpiece
can beïmade without 'spring backffrom-Duralumin
event-"by employing one or the other 'of the
stretching and‘bendi'ng operations,- a wideïvariety
forcer»appliedjtofthe cylinder ldd »to stretch the 60 of irregularly‘or >regularly changing radius forms'V
around the form’block mila.
'
'
. ï By applyingïaisuitable‘controllablebrake, indi
or other> rolled, extruded, ‘or votl'lerwise lshapeizl
metal members.
~
`
`
' l Having now described the invention in’ detail
in reference to the drawings' showing but icertain
cated as awhole‘by the'num'eral Zell, to the rota 65 >examples
ofi construction, it should clearly be
tion ofthe turntable Silmïthe desiredvrelation
between #the bending and the stretchingy of the
understo‘o'dfthat-> the invention Àis ` not
restricted'
thereto> blut ’many deviations tl’ierei’ronfil may bev
workpiece canbewcontrolled; ~ The brake has
beeïn'conveniently' shown as applied tofthe shaft 70 'made within _thescope andspirit of the> appended
i3d mounting“ one‘ofvthe'sprocketsßßar‘
" ' v
.C1aimS.:
Y In Figure 5l is illustrated still another embodi
>`
lWhat is claimed is:'V
f
,
'
f,
~;
y
"
Y
» i.> AA combines stretching >and bending ma'
elongated‘material int'ocon-l
chain mechanism has been eliminated for moving~ ~ ' Vcl'iinevffo-r,shaping
Íng'a
rotatable
bending means hav-_
tours,
„oomprl
l
the hydraulic cylinder> towards the die >'block dur 75
ing -the "contour to lwhich thematerial is tofbeV ' ’
ing 'tl'ie-bendin‘T operation'. This modiiication is
ment 'ci the invention 'wherein' theV sprocket and
7
2,411,801,
8
bent, means movable with said bending means
for gripping one end of said material, means for
rotating said bending means, ñuid pressure actu
ated stretching means adapted to grip said mate
rial at a point spaced from said bending means
being swingable at least in part about a ñxed
point thereon in a direction opposite to the direc
tion in which the turntable rotates during a bend
ing operation.
7. A combined stretching and bending machine
for shaping elongated material into contours
for imparting a stretch to the material as it is
bent around the bending means, means mounting
the stretching means for movement to and from
comprising a rotatable forming die table, means
for rotating the table,. an endless power chain
drive associated with said table and having por
the bending means, and means controlled by the
rotating bending means for controlling the to and 10i tions of the chain moving parallel but in opposite
from position of the stretching means.
direction, and a hydraulic` stretching cylinder in
2. A combined stretching and bending ma
chine for shaping bar material into contours,
comprising two shafts positioned in parallel re
_fixed relation longitudinally of the chain and
pivotally secured thereto.
8. A combined stretching and bending ma
lation a suitable distance apart, a sprocket on 15" chine for bending elongated 'members into prede
each shaft, a chain actively engaging said
sprockets and having two longitudinal portions
moving in opposite directions, die block means
carried for rotation by one of said shafts, stretch
termined shapes, comprising a turntable, a bend
ing die, means for mounting the die on the turn
table, means adapted to anchor the front end
ing means attached to said chain and being in
cooperative relation to said die blo-ck means, and
a reversible power unit in driving connection with
one of said shafts.
3. A combined stretching and bending machine
for rotating the turntable to wrap said member
of one of said members on the turntable, means
around the die while the rear end of said mem
ber is thereby drawn forward toward the die,
fluid pressure actuated means adapted to be con
nected to the rear end of said member for exert
for shaping bar material into contours, compris
ing a shaft, endless iiexible means engaging said
shaft and having two longitudinal portions mov
ing in opposite directions upon rotation of the
shaft, a form block mounted to rotate with said
shaft, a pivoted support fastened to said flexible 304
means, stretching means including a hydrauli
cally operated cylinder adjustably mounted to
said pivoted support and being cooperative with
said form block, and a power unit in driving con
nection with said shaft.
4. A combined stretching and bending machine
ing thereon suiìcient resistance to said forward
movement to stretch said member beyond its elas
tic limit, and means driven from said turntable
rotating means for moving said fluid actuated
means forward toward the die at a predetermined
rate.
9. A combined stretching and bending machine
for bending elongated members into predeter
mined shapes, comprising a bending die, means
adapted to anchor the front end of one of said
members adjacent the die, an endless chain for
rotating the die to wrapsaid member around it
kfor shaping elongated material into contours,
while the rear end of said member is thereby
comprising a table, a vertical shaft passing
drawn forward toward the die, and ñuid pressure
through and being journaled adjacent one end of
actuated means mounted on said chain and
said table, bending means ñxed to said shaft, a 40 adapted to be connected to the rear end of said
second vertical shaft jo-urnaled at the other end
member for exerting thereon suñ‘icient resistance
of said table, a sprocket mounted on each one
to said forward movement to stretch said mem
of said shai‘ts, an endless chain engaging -said
ber beyond its elastic limit.
`
sprockets, a stretching means attached tor said
l0. A combined stretching and bending ma
chain and cooperating with said bendingmeans,
chine for bending elongated members into pre
and a reversible power unit in driving connection
determined shapes, comprising a bending die,
with one of said shafts.
means adapted to anchor the front end of one
5. A combined stretching and bending machine
of said members adjacent the die, means for ro
for shaping elongated material into contours,
tating the die to wrap said member around it
comprising a table, a vertical shaft >passing
while the rear end of said member is thereby
through and being journaled adjacent one end of
drawn forward toward the die, a piston adapted
said table, a forming die ñxed to said shaft, a
to be connected to the rear end of said member, a
second vertical shaft journaled at the other end
hydraulic cylinder housing said piston and
of said table, a sprocket mounted on each one of
mounted in spaced relation to the die, and means
said shafts below the table, an endless chain 55 for supplying hydraulic pressure to said cylinder
engaging said sprockets, a block attached to said .
in front of the piston whereby to resist forward
chain and being guided in a slot cut into and
movement of the piston sufiiciently to stretch said
along one side of the table above said chain, a
member beyond its elastic limit.
fluid pressure motor connected by a vertical pivot
l1. A combined stretching and bending ma
to the block, and material gripping means car 60 chine for bending elongated members into prede
ried in association with the die and with the
termined shapes,> comprising a table, a turn
fluid pressure motor, said fluid pressure motor
table rotatably mounted thereon, a bending die,
being adapted to stretch said material as it is
means for detachab-ly mounting’the die on vthe
wrapped around said forming die.
turntable, means adapted to anchor the front
6. A combined stretching and bending machine 65 end of 4one of said members in any desired/posi
for shaping bar stock into contours comprising a
tion on »the turntable, means for rotating the
turntable, means for rotating the table, a bar
turntable to wrap said member around thedie
stock stretching device,> means operatively con
While the rear end of said member is thereby
necting the stretching device to move itin the
drawnI forward toward the die, a, piston adapted
same direction as the turntable, a gripping device
disposed on the turntable and adapted to holding
one end of the bar stock, a second gripping device
attached to the stretching device and serving to
hold-the other end of said bar stock, and a form
ing die Vpivotally mounted on said turntable and
to be connected to the rear end of said member,
a hydraulic cylinder housing said piston, and
lmeans pivotally mounting the cylinder on said
table on an axis parallel to and a ñXed distance
from the'axis of the turntable, said cylinder being
adapted to receive hydraulic pressure in front of
2,411,801
l
>
9
the piston whereby to resist forward movement
of the piston in the cylinder suiîiciently to stretch
said member beyond its elastic limit.
12. In a stretching and bending machine for>
shaping bar stock into contours,> a turntable,
means for connecting one end of said stock to
the table, means for rotating the table, a stretch
ing device adapted to be connected to the oppo
site end of said stock for holding and stretching
it,«and a forming die mounted on said turntable
for bending said stock as the table rotates and
being adapted to swing during a bar stock bend
ing and stretching operation about a ñxed point
on the turntable in a direction opposite to the
direction in which the turntable rotates.
10
13. In combination, a forming means, means
for rotating the same, holding means adapted to
secure a portion of a length of material to move
with the forming means, means gripping an
other portion of the material, meansA associated
with the gripping means for applying a stretch
to the material, and a chain operatively connected
to the forming means and to the gripping means
for moving the gripping means toward the form
ing means upon rotation thereof.
JAMES s. NIELSEN.
CLYDE B. MITCHELLA.
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