Improvements in the Manufacture of Mandrel-drawn Tubes.
Year: 1893

page_text: Date of Application, 19th July, 1893
Complete Specification Left, 24th Apr., 1894-Accepted, 25th May, 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Mandrel-drawn Tubes.
We, GEORGE EDWARD CASE, of 5, Cheapside, West Hampstead, N.W.
Musician, and DAVID JAMES BLAIKLEY, of 13, Elsworthy Terrace, Primrose
Hill, N.W. Musical Instrument Maker do hereby declare the nature of this
invention to be as follows:-
:-
Our improvements are particularly applicable to the making of such mandrel-
drawn tubes as are very thin in proportion to their length & diameter.
The usual method of finishing such tubes is to place them upon a steel cylindrical
mandrel of the required internal diameter, & to draw the mandrel & tube together
through a hole of the required external diameter in a die or draw-plate. The
mandrel is then reversed end for end & passed through a draw-plate of such a
size that the mandrel only can pass through, & the tube itself is pushed off by
the plate as the mandrel passes through it. When, however, the tube is very thin
in proportion to its length, it is liable to be crippled in being thus pushed off, &
to lessen the tendency of the tube to cling to the mandrel, the latter is sometimes
made slightly conical, & a strictly cylindrical form to the inside of the tube is
not obtained.
Our improvements have in view the more easy withdrawal of the tube from the
mandrel, & we effect this by placing over the drawn tube an extra tube or sleeve
of any convenient thickness & of an easy sliding fit; this sleeve supports the thin
tube lying upon the mandrel in such a way as to counteract its tendency to peel,
buckle, or become corrugated under the pushing action of the die. One end of this
sleeve may either agree exactly in position with the end of the drawn tube next
the die, so that both the sleeve & the drawn tube are pushed off the mandrel
together; or the sleeve may be longer than the tube, & the end of the tube
farthest from the die turned up against the end of the sleeve, so as to receive a thrust
from it. According to whether the first or the second of these methods of utilizing
the sleeve is adopted, the strain upon the tube is either a push or a pull.
We are by these means enabled to produce hard mandrel-drawn cylindrical tubes
in such metals as brass, copper, aluminium, or silver with greater facility & precision
than heretofore.
11.1000
GEORGE E. CASE.
D. J. BLAIKLEY.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Mandrel-drawn Tubes.
GEORGE EDWARD CASE, Musician 5, Cheapside, West Hampstead, N.W.
DAVID JAMES BLAIKLEY Musical Instrument Maker 13, Elsworthy Terrace,
Primrose Hill, N.W. 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 :-
Our improvements are particularly applicable to the making of such mandrel-
drawn tubes as are very thin in proportion to their length & diameter.
The usual method of finishing such tubes is to place them upon a steel cylindrical
mandrel of the required internal diameter, & to draw the mandrel & tube
7

page_text: together through a hole of the required external diameter, in a die or draw-plate.
The mandrel is then reversed end for end & passed through a draw-plate of such
a size that the mandrel only can pass through, & the tube itself is pushed off by
the plate as the mandrel passes through it. When, however, the tube is very thin
in proportion to its length, it is liable to be crippled in being thus pushed off, &
to lessen the tendency of the tube to cling to the mandrel, the latter is sometimes
made slightly conical, & a strictly cylindrical form to the inside of the tube is not
obtained.
Our improvements have in view the more easy withdrawal of the tube from the
mandrel, & we effect this by placing over the drawn tube an extra tube or sleeve
of any convenient thickness & of an easy sliding fit: this sleeve supports the
thin tube lying upon the mandrel in such a way as to counteract its tendency to
peel, buckle, or become corrugated under the pushing action of the die. One end
of this sleeve may either agree exactly in position with the end of the drawn tube
next the die, so that both the sleeve & the drawn tube are pushed off the mandrel
together or the sleeve may be longer than the tube, & the end of the tube
farthest from the die turned up against the end of the sleeve, so as to receive a
thrust from it. According to whether the first or the second of these methods
of utilizing the sleeve is adopted, the strain upon the tube is either a push or a
pull.
We are by these means enabled to produce hard mandrel-drawn cylindrical
tubes, of great lightness, in such metals as brass, copper, aluminium, or silver with
greater facility & precision than heretofore.
'
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is :
1. A method of withdrawing tubes from the cylindrical mandrels upon which
they are drawn, by the use of an extra outer tube or sleeve, substantially as
described in this Specification.
Dated this Twentieth day of April 1894.