Improvements in the Manufacture of Drawn Metal Tubes Provided with Internal Ribs or Projections.
Year: 1889

page_text: Date of Application, 27th June, 1889
Complete Specification Left, 27th Mar:, 1890- Accepted, 3rd May, 1890
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Drawn Metal Tubes Provided
with Internal Ribs or Projections.
I, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, do hereby declare the nature of this invention, which has been com-
municated to me from abroad by Jean Pierre Serve of rue des Servettes, Givors, Rhone,
in the Republic of France, Manufacturer, to be as follows:-
In the manufacture of ordinary drawn or plain smooth tubes made in a general way
without a longitudinal joint or weld one of the extremities of the tube is compressed
or contracted beforehand so as to form a species of point which on the one hand
facilitates the introduction of the tube into the hole or opening in the die or draw
plate and on the other hand provides a firm or stiff piece for the clamps or jaws
to lay hold of.
Under these conditions the internal mandril which is employed in the drawing
process is invariably and necessarily introduced in the tube froin behind or at the rear
end being retained in position by a rod attached to the end of the bench farthest from
the die.
In dealing with tubes provided with longitudinal internally projecting ribs or webs
it is extremely difficult to introduce the mandril into the tube by pushing it in at the
rear end and it is far preferable to insert it at the front end but when this front end
bas been compressed or contracted as usual in the manufacture of plain tubes it
becomes necessary to cut off this compressed or contracted part before the mandril
can be introduced and as this operation has to be repeated at each draw or passage of
the tube through the die it involves great waste of material.
This waste is obviated according to this invention by conducting the operation as
hereinafter described.
In the manufacture of drawn metal tubes according to this invention both ends of
the tube are left open the end of the tube that is first introduced into the die not being
compressed to form the point and the drawing is effected as follows:-
At each draw or passage of the tube through the die the operation is commenced by
introducing into the tube the mandril provided with its rod, this being indispensable
for the drawing action. This mandril is introduced at the front end of the tube being
the end which first enters the die taking care to push in the mandril to a sufficient
distance say 8 or 10 inches for example but this distance varies slightly of course
according to the form of the head stock of the draw bench.
After the mandril has thus been placed in position the diameter of the end of the
tube projecting beyond the mandril is contracted or reduced to a suitable amount to
enable it to pass readily into the die and in order to prevent the jaws of the
grippers or clainps from crushing this end of the tube a metal filling piece or block is
introduced being of a diameter to fit very exactly into the tube and of such length as
to slightly project beyond the end in order to facilitate its withdrawal after the passage
of the tube through the die.
It will be understood that in order to facilitate the introduction of this filling piece
into the tube as aforesaid the whole or part of the internal projections or ribs in the
tube may be removed in a lathe or otherwise from that part of the tube into which
this block is inserted.
To produce the necessary preliminary contraction of this part of the tube either of
the means hereinafter described may be employed. At the commencement of the
operations the metal tube being of sufficient thickness the diameter of its end may be
reduced in the first instance by turning or cutting down a small portion of the exterior
of the extrenity so as to enable it to be readily introduced into the die and then

page_text: after a few passages the interior is enlarged at the extremity to admit of the
introduction of the mandril to a certain depth as herein before described. For the
succeeding drawings the extremity of the tube is reduced either by hand that is to
say by hammering it between swages or by introducing it between stamps or tools
acting mechanically in the usual manner. This operation may be facilitated by
slitting or dividing the end of the tube longitudinally with two or three saw cuts
the sides of the tube are thus enabled to be brought nearer together without
difficulty.
The clamping jaws which hold the end of the uncontracted tube must of course
be suitably constructed according to the nature of the work and are preferably of
the description working with a wedging action so that the grip tightens automatically
as the strain or resistance of the tube in passing through the die increases.
Datal thin 07th d... f T1000
J. H. JOHNSON & Co.,
17, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Drawn Metal Tubes Provided
with Internal Ribs or Projections.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention (which has been com-
municated to me from abroad by Jean Pierre Serve of rue des Servettes, Givors, Rhone
in the Republic of France Manufacturer) and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement
In the manufacture of ordinary plain smooth drawn tubes made in a general way
without a longitudinal joint or weld one of the extremities of the tube is compressed
or contracted beforehand so as to form a species of point. which not only facilitates the
introduction of the tube into the hole or opening in the die or draw plate but also
provides a firm or stiff piece for the clamps or jaws to lay hold of.
Under these conditions the internal mandril which is employed in the drawing
process is invariably and necessarily introduced in the tube from behind or at the rear
end being retained in position by a rod attached to the end of the bench farthest
from the die or draw plate.
In dealing with tubes provided with longitudinal internally projecting ribs or webs
it is extremely difficult to introduce the mandril into the tube by pushing it in at the
rear end and it is far preferable to insert it at the front end but when this front end
has been compressed or contracted as usual in the manufacture of plain tubes it
becomes necessary to cut off this compressed or contracted part before the mandril
can be introduced and as this operation has to be repeated at each draw or pass of
the tube through the die it involves great waste of material.
This waste is obviated according to this invention by conducting the operation as
hereinafter described.
In the manufacture of drawn metal tubes according to this invention both ends of
the tube are left open the end of the tube that is first introduced into the die not
being compressed to form the point and the drawing is effected as follows:—
At each draw or pass of the tube through the die the operation is commenced by
introducing into the tube the mandril provided with its rod, this being indispensable
for the drawing action. This mandril is introduced at the front end of the tube being
the end which first enters the die taking care to push in the mandril to a sufficient
distance say 8 or 10 inches for example but this distance varies slightly of course
according to the form of the head stock of the draw bench.
After the mandril has thus been placed in position the diameter of the end of the
tube projecting beyond the mandril is contracted or reduced to a suitable amount to
enable it to pass readily into the die and in order to prevent the jaws of the grippers
or clamps from crushing this end of the tube a metal filling or block or lining piece

page_text: is introduced into the tube end being of a diameter to fit very exactly into the tube
and of such length as to slightly project beyond the end in order to facilitate its
withdrawal after the passage of the tube through the die.
It will be understood that in order to facilitate the introduction of this filling piece
into the tube as aforesaid the whole or part of the internal projections or ribs in the
tube may be removed in a lathe or otherwise from that part of the tube into which
this block is inserted.
To produce the necessary preliminary contraction of this part of the tube the
means hereinafter described may be employed. At the commencement of the
operations the metal tube being of sufficient thickness the diameter of its end may
be reduced in the first instance by turning or cutting down a small portion of the
exterior of the extremity so as to enable it to be readily introduced into the die and
then after a few passes the interior is enlarged at the extremity to admit of the
introduction of the mandril to a certain depth as hereinbefore described. For the
succeeding drawings the extremity of the tube is reduced by hammering it between
swages or by compressing or upsetting it between dies. This operation may be
facilitated by slitting or dividing the end of the tube longitudinally with two or three
saw cuts the sides of the tube are thus enabled to be brought nearer together without
difficulty.
The clamping jaws which hold the end of the uncontracted tube must of course be
suitably constructed according to the nature of the work and are preferably of the
description, working with a wedging action so that the grip tightens automatically as
the strain or resistance of the tube in passing through the die increases.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. The improvements in the manufacture of drawn tubes with internal longitudinal
projections whereby the contraction or crushing together of the extremity of the
tube that is introduced into the die and seized by the tongs or clamps is rendered'
unnecessary substantially as herein before described.
2. The method of manufacture consisting in leaving open both ends of the tube to
be drawn and introducing the mandril at the end which first enters the die the
internal projections on the tube being preferably taken out beforehand for a certain
distance at this extremity so as to facilitate the introduction of the said mandril and
the gradual reduction of this part of the tube substantially as herein before described.
3. Effecting the reduction of the extremity of the tube at the end which first
enters the die by turning hammering or upsetting by compression as and for the
purpose substantially as hereinbefore described.
4. The introduction into the extremity of the tube where it first enters the die of a
filling block or lining piece accurately fitting into the tube so as to prevent the
pressure of the clamping jaws from injuring the shape of this part of the tube
during the drawing process the said filling block or lining piece being capable of
being removed from the tube after each pass substantially as herein before described.
5. The method of drawing tubes as herein before set forth in combination with the
employment of self tightening clamping devices with inclines or wedging action for
holding the tube securely during the drawing process substantially as bereinbefore
described.
Dated this 27th day of March 1800