Improvements in Machinery to be Employed in connection with the Manufacture of Seamless Steel Tubes.
Year: 1896

page_text: Date of Application, 23rd May, 1896-Accepted, 4th July, 1896
COMPLETE SPECIFICATION.
Improvements in Machinery to be Employed in connection with the
Manufacture of Seamless Steel Tubes.
We, ROBERT FREDERICK HALL, of Sherlock Street, in the City of Birmingham,
Manufacturer, FREDERICK WARWICK, of The Dingles, Shirley, near Birmingham
aforesaid, Manufacturer, and THOMAS SMITH, of Wharfe Street, Aston, near
Birmingham aforesaid, Manufacturer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
In manufacturing weldless steel tubes produced upon solid bar mandrils, it is
difficult to withdraw the tube from off the mandril or to remove the mandril from the
tube and this is done often at a great risk of injuring the constitution of the metal
from which the said tube is made. The removal is usually accomplished by what
is known as a reeling machine which rotates the tube and mandril together and, by
applied pressure, slightly spreads or increases the internal diameter of the tube
formed and thereby loosens the same on the mandril," when the said tube can be
withdrawn.
The removing of thin gauge tubes (such as are usually used in cycle work) is
fraught with difficulties on account of the liability of the same to be externally
injured and scratched, and oftentimes burst.
According to our improvements, the walls of a drawn tube are loosened from its
mandril by a straight rolling process.
Figure 1 of the accompanying drawing represents in front elevation a holster or
frame having mounted within it, two pulley shaped rolls practically forming an
elliptically shaped eye, with the major axis displaced horizontally and the minor
axis vertically, and between opposite vertical parts of which the tube comes, the
nip being upon the top and bottom of the tube, but the ends of the rolls have
clearances which admit of the flowing of the metal displaced by the top and
bottom nips.
Figure 2 is a side elevation of Figure 1.
Figure 3 represents, upon an enlarged scale, a section of the rolls, with the tube
and mandril coming between them.
Figure 4 represents the holster or frame applied to an ordinary draw-bench.
Figure 5 is a like view of a modified form of rolls which have four points of
contact with the tube or two opposite top and bottom nips and four clearances to
allow of the slight expansion of the metal of the tube.
The same letters of reference indicate corresponding parts in Figures 1 to 4 of
the drawing.
a and b are a pair of sheave-pulley shaped rolls, with their axes a², 3, respectively
mounted to run freely within bearings c, e, of the holster or frame d, and the ends e¹,
of the adjustable stirrup e, adjusted by a hand screw f.
g is a bar mandril and h is the tube, nipped between the top and bottom sides of
the internal support and the top and bottom surfaces a', 6, of the rolls a and b,
which have opposite side clearances i, left to admit of the slight flow or expansion
of the walls of the tubing, which are compressed by the top and bottom nips.
Thus, after the tube has been drawn onto the mandril by the ordinary process of
drawing seamless steel tubes, both tube and mandril are forced or drawn through
the elliptical eye of the expanding rolls, and by the nipping of the metal at two
opposite points, with corresponding clearances being left at the sides to admit of

page_text: the expansion of the metal slightly displaced by the opposite nips. The tube is
thereby slightly elongated and its bore slightly enlarged (see dotted lines o,
Figure 3), just sufficient to admit of the same being easily stripped off the
mandril.
In Figure 5, a and b are the rolls having open V-sectioned or sheave pulley
shaped faces and with the nips a, a, b, 61, coming onto the tubes at four points
and having four clearances i, i, for the metal to flow into when displaced (see
dotted lines o¹, Fig. 5) by the pressure of the rolls at the contacts or nips.
If necessary, the holster may be made to rotate bodily, so that the rolls form as
it were a rotatory die through the eye in which the tube and mandril are drawn.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
The process of removing solid drawn tubes from their mandrils by drawing the
same through rolls having nips or points of contact alternated by clearances.
Dated this 21st day of Mar 1896.
ROBERT FREDERICK HALL,
FREDERICK WARWICK,
THOMAS SMITH,
By Henry Skerrett,
24 Temple Row, Birmingham, Agent for Applicants.