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Патент USA US2105150

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Patented Jan. 11, 1938
2,105,150
‘ UNITED STATES PATENT OFFICE
2,105,150 ,
TUBE PUSH BENCH
Kai-01y Korbuly, Csepel, Hungary, assignor to
the ?rm Tube Industrial Participation Limited,
Breganzona-Lugano,
a corporation of Switzer- '
land
Application January 21, 1937, Serial No. 121,677
1
'
Germany June 29, 1936
2 Claims. (01. 80-12):
This invention relates to push bench drawing
at least the last third part of the total length of '
the whole series of passes and is acted on at one
time by not less than one third of the total num
ber of passes.
apparatus for the manufacture of metal espe
cially iron or steel tubes of the kind by which a
heated somewhat thick cup-shaped hollow billet
carried on an end of a mandrel is pushed through.
Preferably the passes are disposed at such dis
tances apart that the partially formed tube when
it enters the smallest roll pass .extends at least
through-passes between rolls which passes de
crease successively in cross-sectional area in a3
forward direction and which rolls are not driven,
whereby the billet is reduced in thickness and
10 spread out lengthwise along the mandrel until
the billet is brought to the form of a tube of the
required thickness and length.
In the operation of push bench apparatus in '
which ring dies are employed instead of through
15 passes between rolls, if the resulting tube is to be
at least ten times the length of the billet treated
and the drawing is‘ to be effected in one opera
tion, the ring bed must be of a length to permit
the spacing of the dies at such distances that the
20 tube being drawn engages at most four, and in
exceptional cases perhaps ?ve dies simultane
ously, when the head end of the tube enters the
last orsmallest die, while in the major part of the
ring bed it is acted on only by two or three dies
over the second half of the total length of the
whole series of‘passes and is worked on simul
taneously by not less than half of the total num
ber of passes. The total length of the series of
passes may be even less than the ?nal length of
the drawn tube, whereby the length of stroke re
quired for the push bench can be less than twice
the length of the tube to be produced.
'
The trough diameter of the rolls of a pass, that 15
is, the diameter of the rolls measured at the bot‘
tom of the circumferential groove is, preferably,
in the first or largest pass such that it does
not exceed the pass diameter by more than 20%,
while the trough diameter of the rolls of any 20'
other pass is smaller than the trough diameter
of the rolls of the largest pass. The trough di
ameters of the rolls in a pass must be so chosen
25 simulv neously. In order to avoid a rupture ofv as
to have a relation to the pass diameter of the
the metal during the lengthening of the billet to respective
pass such that the ratio of thetrough
more than ten times its original length a total
co
number of dies exceeding 20 must be employed.
The partly formed tube on entering the last or
smallest die will thus be acted on simultaneously
by less than one fourth, and generally by less than
one ?fth, of the total number of dies which are
distributed along a shorter distance than the last
quarter of the total length of the ring die bed,
which has to be more than twice the length of the
tube produced. The long stroke ‘required not
only results in slower working, but in conjunction
with the cooling effect of the mandrel would cause
25
diameter to the pass diameter in the several
passes decreases gradually from the last pass
towards the ?rst pass.
One form of push bench drawing apparatus
according to the present invention will now‘ be 80
described by way of example and with reference
to the accompanying partly diagrammatic draw
ing wherein:
Fig. 1 is a diagrammatic elevation of the push
bench,
85
Fig. 2 shows to a larger scale and diagrammati- '
cally the partly formed tube at the point at which
the metal to cool so quickly that di?iculty would _ it enters the smallest roll pass and
Fig. 3 shows-a front elevation of a roll pass
for the heating e?ect produced by the friction
40 be experienced in drawing the tube were it not
between the dies and the tube. This, however,
means that considerable power is required to
push the tube through the dies.
45
in is an object of the present invention to pro~
vide apparatus of the kind described by which
these disadvantages are overcome.
According to the present invention in push
bench drawing apparatus of the kind described
50 the number of roll passes is greater than the ?g
having three rolls arranged at 120°.
40
Referring ?rst to Fig. 3 r are the rolls which
are loosely journalled in a ‘carrier or housing s.
The rolls are. arranged at 120° and form a pass
of whichD is the pass diameter. d is the trough
diameter or diameter of the rolls measured at 45
the bottom of the groove 9. While the pass
illustrated in Fig. 3 has three rolls it will be
understood that according to requirements two
rolls or more than three rolls may be employed.
at
ure indicating the relation between the length of ' ,
Referring now to Fig 1 the push bench is in
the drawn tube and the original length of the
‘
tended
to stretch the billet b shown by ‘dotted
billet, and said passes are disposed at such dis
tances apart that the partiallyfor‘med tube when lines from its length L to for example the length
55 it enters the last and smallest pass extends over 13L, for which purpose more than thirteen passes,
for example seventeen passes a1—arz, arewar- 55
2,105,150
2
ranged coaxially along the bench. The heated
billet I) carried on the end of the mandrel m
is pushed through the series of passes and after
it emerges from the last pass a“ it will have a
length of, for example, 13L as indicated by the
' dot and dash line at the left hand end of the
?gure. The trough diameter d1’I of the rolls of
the smallest and last pass a" is, for example 1.3
times the pass diameter D of this pass, while
10 the trough diameter d1 of the ?rst and largest
pass a1 is equal to the pass diameter of this
said ?rst pass. Hence, the ratio
d
D
15
decreases gradually from the smallest and last
pass a" towards the ?rst and largest pass al.
The partially drawn tube w is indicated in
Fig. 1 in full lines and it is at the stage when
it is entering the smallest pass a". At this
20
stage the partially formed tube extends over a
length of 6.7 L, that is to say over a length
which is larger than half of the total length 11L
of the pass bed. At this stage also the tube is
25 acted on simultaneously by eleven passes aL-a"
at one time. Fig. 2 shows the partly drawn tube
at this stage and to a larger scale. The total
number of passes in the push bench illustrated
being seventeen the number of passes acting on
the tube at this stage, namely, eleven, is substan
tially greater than one third of the total num
ber of passes and is even greater than half
the total number of passes.
.
The total number of passes (ll-a" in the ap
paratus illustrated diagrammatically in Fig. 1
extends over a length which is about equal to
11L, that is to say, the total length of the passes
is less than the length of the tube produced
which is indicated in Fig. 1 as being 13L.
What I claim is:—
'
1. A push bench drawing apparatus for pro
ducing a tube from a hollow billet, the length
of which tube is at least ten times the length
of the hollow billet, comprising a mandrel and
roll passes, in which the rolls are idle, disposed
in front of the mandrel, the number of said passes
being greater than the ?gure indicating the re
lation between the length of the drawn tube and
the original length of billet, said passes being
disposed at such distances apart and decreas
ing successively in cross-sectional area in for
ward direction in such stages that the tube on
entering the last and smallest pass reaches a
length which extends at least to the last third
of the total length of the whole series of passes
and is acted on simultaneously by not less than
20
one-third of the total number of passes.
2. A push bench drawing apparatus for pro
ducing a tube from a hollow billet, the length
of which tube is at least ten times the length
of the hollow billet, comprising a mandrel and
roll passes, in which the rolls are idle, disposed
in front of the mandrel, the number of said
passes being greater than the ?gure indicating
the relation between the length of the drawn
tube and the original length of billet, said passes
being disposed at such distances apart and de- creasing successively in cross-sectional area in
forward direction in such stages that the tube
on entering the last and smallest pass reaches
a length which extends at least to the second
half of the total length of the whole series of
passes and is acted on simultaneously by not
less than one-half of the total number of passes.
KARoLY KORBULY.
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