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Патент USA US2405478

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Aug- 6, 1946-
s. WESTIN ETAL'
2,405,478
METHOD OF THICKENING A LOCALIZED LONGITUDINAL ELEMENT IN A TUBE
Filed Oct. 6, ‘1944
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INVENTORj.’
ATTORNEY
2,405,478
Patented Aug. 6, 1946
UNITED STATES PATENT OFFICE
2,405,478
METHOD OF THICKENING A LOCALIZED
LONGITUDINAL ELEMENT IN A TUBE
Sven Westin, West Allis, and Axel Westin, Mil
waukee, Wis., assignors to A. 0. Smith Corpora
tion, Milwaukee, Wis., a corporation of New
York
Application October 6, 1944, Serial No. 557,500
14 Claims. (Cl. 219-3)
1
2
This invention relates to a method of thicken
ing a localized longitudinal element in a tubular
the blank on line 2-2 of Figure 1 and looking at
blank. The invention employs the general prin
ciples of electro-fcrming set forth in U. S. Letters
Fig. 3 is a longitudinal section through the
electrode dies taken on line 3-3 of Fig. 2 and
Patent No. 2,309,561 and may be employed in con
showing the forming operation;
nection with various tube forming operations
such as those set forth in U. S. Letters Patent No.
Fig. 4 is a transverse section through the form
ing apparatus taken on line 4—-4 of ‘Fig. 3 and
2,345,692 and in application, Serial No. 463,958,
,?led October 30, 1942, for Electric pipe forming,
showing the segmental upsetting of the present
invention;
the forming electrodes;
Fig. 5 is a transverse section through the ?n
ished blank as it emerges from the forming dies,
taken on line 5—-5 of Fig. 3; and
Fig. 6 is a schematic side elevation similar to
Fig. 1 and showing an electrical oscillator for
forming dies wherein the blank is progressively 15 carrying out the invention.
The apparatus illustrated includes the usual
heated to forming temperatures by resistance
rotary chuck I for gripping the end of a tubular
heating current ?owing circumferentially through
cylindrical blank 2 to be formed. The chuck I is
the blank in progressively adj acent circumferen
mounted for horizontal movement by the piston
tial segments thereof.
In these operations, the blank being continu 20 3 of a double acting hydraulic cylinder 4 for mov
now Patent No. 2,371,090, dated March 6, 1945.
The general principles of electro-forming de
scribed in said patents and application involve
the rotating of a blank in pressure contact with
a plurality of circumferentially spaced electrode
ously rotated relative to the electrode dies, there
ing the same axially to feed the blank 2 longi
tudinally during forming operations.
is a uniform heating and contraction in diameter
The chuck l is rotated or oscillated by a motor
of the blank throughout its circumference in the
5 driving the speed reduction transmission 6.
region of die contact therewith, and as the blank
The forming apparatus comprises two or more
is moved axially into or through the dies it is 25
complementary circumferentially spaced elec
progressively heated and formed in successive
adjacent longitudinal regions.
The principal object of the invention is to pro
vide a method for upsetting a localized longitudi
nal portion of a tubular blank.
Another object is to provide a method for si
multaneously reducing a tubular blank in diam
eter and upsetting a localized segmental portion
thereof.
The invention is carried out by varying the-time
of heating of the various circumferential seg
mental portions of the blank by the circumfer
entially ?owing heating current. This may be
done in various Ways. For instance the blank
trode forming dies 1 and 8 having tapered die
surfaces providing a substantially conically
shaped die throat 9 through which the blank 2.
39 is pushed by chuck I, the die throat being of
somewhat smaller diameter than the blank.
The dies 1 and 8 constitute the opposite elec
trode terminals of a secondary transformer cir
cuit H], the primary ll of the transformer being
connected by leads [2 and switch I3 to a suit
able source | 4 of electric power.
In ordinary operations of reducing the blank
2 in diameter with a uniform wall thickness, the
blank is rotated continuously at a constant speed
may be given an oscillating or Varying speed ro 40 as it is fed forwardly through’ the dies. The for
tary motion wherein one or more segmental por
ward end of the blank ?rst contacts the dies on
tions of the blank are disposed to bridge the gap
the tapered or inwardly inclined die surfaces and
between the electrode dies for a longer period
as the heating current is applied it ?ows circum
than do adjacent portions of the blank, or by
controlling the heating current applied to the 45 ferentially through successive adjacent segmental
portions of the blank bridging the circumferen
blank through the electrode dies in synchronism
with the rotary movement involved so as to effect
tial gap between the electrodes until a circum
ferential or segmental band of the blank in the
region of contact of the electrode dies becomes
The invention is illustrated in the accompany 50 heated to a softened state. Th‘ereupon the heat
ed portion of the blank yields inwardly along the
ing drawing in which:
inclined die surfaces under the axial pressure of
Figure 1 is a schematic side elevation, parts
the feeding piston 3. This lengthens the pres
being shown in section, showing an apparatus for
sure contact of the electrode dies and broadens
reducing a tube in diameter;
Fig. 2 is an enlarged transverse section through 55 the band of heating and forming until the blank
greater heating of a predetermined segmental
portion or portions of the blank during forming.
aged/r78
3
progressively passes through the die th'roat 9 in
reduced form.
According to the invention the above opera
tions are modi?ed in order to provide a greater
heating effect, or to limit the heating effect to
4
We claim:
1. The method of thickening a longitudinal
segmental portion of a tubular blank while re
ducing the blank in diameter, comprising produc
ing relative rotation and shaping pressure be
one or more predetermined segments of the blank
tween the blank and a multipart forming means,
whereby said segments will be upset greater than
the intermediate or adjacent blank stock.
This may be accomplished in several ways. The
speed of rotation of the blank may be varied to 10
simultaneously therewith passing a heating cur
provide a low speed or dwell in a predetermined
portion of the cycle of each revolution so that a
rent of electricity through the blank from one
part of said forming means to another part there
of in a circumferential direction, and selectively
varying the time of heating to obtain a heating
di?erential between adjacent segments of the
blank during shaping thereof.
given segmental part of the blank is subjected
2. The method of thickening a longitudinal
to a longer time of heating than the adjacent
parts of the blank. Another way of accomplish 15 segmental portion of a tubular blank while reduc
ing the blank in diameter, comprising producing
ing the varied heating is to oscillate the blank by
relative rotation and shaping pressure between
alternate reversal in rotation, limiting the rotary
the blank and a plurality of radially opposed
movement in either direction short of a complete
electrode forming dies to simultaneously heat and
revolution.
shape the blank, and selectively heating adja
For thin tubes where only a narrow upset is
cent segmental portions of the blank by regulat
desired, it might be possible not to rotate the
ing the relative heating current passing there
blank at all and to merely feed it into the die.
through from said dies to obtain a heating dif
Such an operation, however, would tend to ex
ferential therebetween.
trude the upset portion radially outward in the
space between the dies much as set forth in U. S. 25
Letters Patent No. 2,345,692, above referred'to.
In order to prevent outward extrusion of the
upset portion and to obtain a product of cir
3. The method of thickening a longitudinal
segmental portion of a tubular blank while re
ducing the blank in diameter, comprising produc
ing relative rotation and shaping pressure be
tween the blank and a plurality of radially op
posed electrode forming dies to simultaneously
semblance of rotary movement of the blank dur
ing forming. By doing this the upset l5 of the
heat and shape the blank, and ‘selectively heat
ing adjacent segmental portions of the blank to
blank is provided on the inside as a thickened
obtain a heating differential therebetween by
segment.
varying the speed of rotation of the blank rela
The actual width of the upset will depend upon
tive to the electrodes in a predetermined cycle
the width. of the space between the electrode
for each revolution.
dies and the required amount of rotary move
4. The method of thickening a longitudinal seg
ment of each oscillation or length of dwell em
mental portion of a tubular blank while reducing
ployed to produce the same.
The various controls for the rotary movement
the blank in diameter, comprising producing rela
desired may be provided in the transmission 6 40 tive rotation and shaping pressure between the
blank and a plurality of radially opposed electrode
which contains the reduction gearing and cranks
forming dies to simultaneously heat and shape the
cams for varying the speed of rotation or for
effecting a predetermined stroke of oscillation of
blank, and selectively heating adjacent segmental
portions of the blank to obtain a heating differen
the chuck l.
Where a more narrow upset is desired than can
tial therebetween by giving an oscillation of alter~
nate reversals in direction of relative rotation be
be obtained in the manner above described, it is
possible to limit the flow of heating current to a
tween the blank and the electrodes.
smaller segment of the blank by cutting on and
5. The method of thickening a longitudinal
off the heating current as shown in Fig. 6. In
segmental portion of a tubular blank while re
this modification the transmission 6 additionally
ducing the blank in diameter, comprising pro
contains a control switch [6 which interrupts
ducing relative rotation and shaping pressure be
the primary circuit I l of the transformer in syn
tween the blank and, a plurality of radially op
posed electrode forming dies to simultaneously
chronism with the rotary movement of the chuck
i so that the heating current is applied to the
heat and shape the blank, and selectively heating
blank only or mainly in the segment to be upset.
adjacent segmental portions of the blank to ob
In this way a better control of the heating and
tain a heating di?erential therebetween by vary
ing the heating current in a predetermined cycle
upsettting can be obtained.
for each revolution of the blank relative to the
If desired the differential heating may be ob
electrodes.
tained by this latter intermittent application of
6. The method of thickening a longitudinal
the heating current without varying the speed of 60
segmental portion of a tubular blank while re
rotation or oscillating the blank. When this is
ducing the blank in diameter, comprising produc
done the blank may be rotated continuously and
ing
relative rotation and shaping pressure be
at a uniform speed and the current cut on and
off or varied during each revolution to give the 65 tween the blank and a plurality of radially op~
posed electrode forming dies to simultaneously
desired heating of one or more segments. In
heat
and shape the blank, and selectively heat
this operation there may be some tendency for
ing adjacent segmental portions of. the blank to
the upset segment of the blank to take the form
obtain a heating differential therebetween by re
of a spiral due to the twisting of the heated blank
ducing the time of the application of the heating
under torque loads in forming. The oscillating 70 current in the adjacent segments which are not
of the blank in alternate reversals of rotation
to receive the maximum upset.
avoids this.
7. The method of thickening a longitudinal
Various embodiments of the invention may be
segmental portion of a tubular blank while re
employed within the scope of the accompanying
ducing the blank in diameter, comprising pro
claims.
75 ducing relative rotation and shaping pressure be
cular outer contour it is desirable to maintain a
5
2,405,47 8
tween the blank and a plurality of radially op
posed electrode forming dies to simultaneously
heat and shape the blank, and selectively heat
ing adjacent segmental portions of the blank to
obtain a heating differential therebetween by ap
plying the heating current only in the region of
the segment or segments to be upset.
8. The method of treating a circular metallic
body, comprising applying forming pressure to
a plurality of opposed segmental areas in the
region of forming of the body, transferring said
forming pressure circumferentially to successive
adjacent areas of the body in recurrent cycles,
simultaneously therewith applying heat to sue
cessive adjacent segmental areas of said body in
termediate the areas of pressure application, and
selectively varying the application of heat to the
6
dies, and altering the heating current for differ
ent segmental portions of the body to obtain a
differential thickening of the body in adjacent
segments thereof.
12. An apparatus of the class described, com
prising a plurality of cooperating forming dies
circumferentially arranged around a tubular
blank to be electrically heated and formed,
means to effect relative rotation between the
blank and dies in radial pressure contact with
each other, means to pass a heating current
through the blank from one of said dies to an
other of said dies, and means connected with
said ?rst named means for selectively controlling '
the application of heating current to a predeter
mined segmental region of the blank differently
from that of an adjacent segmental region and
in co-relation to the relative rotation between
the blank and dies.
a greater thickening of the same.
20
13. An apparatus of the class described, com
9. The method of treating tubular metallic
prising a plurality of cooperating forming dies
bodies comprising applying shaping pressure to
circumferentially arranged around a tubular
a body by a plurality of ciroumferentially spaced
blank to be electrically heated and formed, means
electrode dies which cooperate to supply a resist
to effect relative rotation between the blank and
ance heating current ?owing circumferentially
dies in radial pressure contact with each other,
through the segmental portions of the body be
means to pass a heating current through the
tween the dies, relatively rotating said body and
blank from one of said dies to another of said
dies, and applying the heating current selectively
dies, and means to alter the relative rotary move
to different segmental areas of the body.
ment between the blank and dies to increase
10. The method of treating tubular metallic 30 the time of heating of a predetermined segmental
bodies comprising applying shaping pressure to a
region of the blank as compared to that of an
body by a plurality of circumferentially spaced
adjacent segmental region.
electrode dies which cooperate to supply a resist
14. An apparatus of the class described, com
ance heating current ?owing circumferentially
prising a plurality of cooperating forming dies
through the segmental portions of the body be
circumferentially arranged around a tubular
tween the dies, relatively rotating said body and
blank to be electrically heated and formed, means
dies, and altering the rotary movement to obtain
to effect relative rotation between the blank and
a selective heating of different segmental por
dies in radial pressure contact with each other,
tions of the body and e?ect a thickening of the
means to pass a heating current through the
body to elTect greater heating of one segment as
compared to adjacent segments to thereby obtain
body in one or more segments.
11. The method of treating tubular metallic
bodies comprising applying shaping pressure to
a body by a plurality of circumferentially spaced
40 blank from said dies, and means to alter the heat
ing current to eiTect a selective control of the
heating of a predetermined segmental region of
the blank di?erently from that of an adjacent
electrode dies which cooperate to supply a resist
segmental region.
ance heating current ?owing circumferentially 45
SVEN WESTIN.
through the segmental portions of the body be
AXEL WESTIN.
tween the dies, relatively rotating said body and
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