Improvements in Flexible Metallic Tubes and Apparatus for their Manufacture.
Year: 1890

page_text: Date of Application, 25th Sept., 1890
Complete Specification Left, 11th June, 1891-Accepted, 18th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in Flexible Metallic Tubes and Apparatus for their
Manufacture.
I, FREDERICK WALTON, of No. 4 Portugal Street, Lincoln's Inn Fields, in the
County of London, Manufacturer, do hereby declare the nature of this invention
to be as follows:-
In the Specifications No. 9478 of 1885, No. 1390 of 1889 and No. 7906 of 1889
are described methods and apparatus for manufacturing flexible metallic tubes by
helically coiling a suitably corrugated strip of metal so that each convolution
interlocks with the next.
The present invention relates to methods of and apparatus for corrugating the
strip in such a manner as to obtain great tightness of the tube against leakage
consistently with great flexibility. For this purpose the corrugations of the tube
are so. formed that part, say the rear part, of one convolution projects like a rib
with an outer face parallel to the axis fitting closely within the front part of the
next convolution, which has its inner face parallel to the axis so that the one part
fits in the other as a piston in a cylinder. In some cases a small groove is formed
in the projecting rib to hold a thread or string of suitable packing. In the machine
for manufacturing the tube, several pairs of rollers are arranged to act successively
so as to give the desired corrugations to the continuous metal strip which is drawn
from a roll through a bath of lubricant. In order to apply to the strip sufficient
tension to draw it through the corrugating rollers, the strip is coiled, after passing
from between the rollers, several times round a drum or capstan which is geared to
revolve with surface speed somewhat greater than that of the rollers, so that there
is a certain slip, which ensures a drag on the strip. In cases where the strip is of
thick metal, or the corrugations are of considerable depth, there may be several sets
of the corrugating rollers with several intermediate capstans to give the necessary
drag. From the capstan or the last of several capstans the corrugated strip passes
between a pair of rollers and thence to the revolving mandril, round which it is
coiled by three pressing rollers in the known manner, a thread or string of packing
being if required, fed into the coils. As the strip is about passing under the first
of the three pressing rollers, a stationary blade is applied to it in such a manner as
to support the inwardly projecting edge of that part of the corrugated strip which
forms the equivalent to a cylinder, so as to ensure that, in the act of coiling, the
outer surface of that part of the convolution should preserve the cylindrical
form without curving inwards, as it would do unless its edge were supported as
described.
Dated this 25th day of September 1890.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Flexible Metallic Tubes and Apparatus for their
Manufacture.
I, FREDERICK WALTON of No. 4 Portugal Street, Lincoln's Inn Fields in the
County of London, 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 the Specifications No. 9478 of 1885, No. 1390 of 1889 and No. 7906 of 1889
Price 8d3

page_text: are described methods and apparatus for manufacturing flexible metallic tubes by
helically coiling a suitably corrugated strip of metal so that each convolution
interlocks with the next.
The present invention relates to methods of and apparatus for corrugating the
strip in such a manner as to obtain great tightness of the tube against leakage
consistently with great flexibility. For this purpose the corrugations of the tube
are so formed, that part, say the rear part, of one convolution projects like a rib
with an outer face parallel to the axis fitting closely within the front part of the
next convolution, which has its inner face parallel to the axis so that the one part
fits in the other as a piston in a cylinder. In some cases a small groove is formed
in the projecting rib to hold a thread or string of suitable packing. In the machine
for manufacturing the tube several pairs of rollers are arranged to act successively so
as to give the desired corrugations to the continuous metal strip which is drawn
from a roll through a bath of lubricant. In order to apply to the strip sufficient
tension to draw it through the corrugating rollers, the strip is coiled, after passing
from between the rollers several times round a drum or capstan which is geared to
revolve with surface speed somewhat greater than that of the rollers, so that there
is a certain slip, which ensures a drag on the strip. In cases where the strip is of
thick metal, or the corrugations are of considerable depth, there may be several
sets of the corrugating rollers with several intermediate capstans to give the
necessary drag. From the capstan or the last of several capstans, the corrugated
strip passes between a pair of rollers and thence to the revolving mandril, round
which it is coiled by three pressing rollers in the known manner, a thread or string
of packing being if required, fed into the coils. As the strip is about passing under
the first of the three pressing rollers, a stationary blade is applied to it in such a
manner as to support the inwardly projecting edge of that part of the corrugated
strip which forms the equivalent to a cylinder, so as to ensure that, in the act of
coiling, the outer surface of that part of the convolution should preserve the
cylindrical form without curving inwards, as it would do unless its edge were
supported as described.
Fig. 1 of the accompanying drawings is a front view and Fig. is a plan of the
machine according to my invention for making flexible metallic tubes, part of
the side of which is shewn in longitudinal section to an enlarged scale by Figs. 3
and 3A.
b
The strip of metal which is to form the tube may be corrugated in various shapes
so that the convolutions shall interlock, but I find that a form of corrugation like
that shewn in Figs. 3 and 34 gives great tightness against leakage consistently with
great flexibility the part a of each convolution forming, as it were, a short cylinder
in which the part of the next convolution can move to and fro as a piston fitting
the interior of a. I sometimes form in the part b a small continuous groove in which,
while the strip is being coiled, a thread of caoutchouc or other suitable packing
material is lodged, this thread constituting a packing for the piston part b. This
packing however is not necessary, especially when the tube is subjected to consider-
able internal pressure because this pressure acting on the interior of the part b as
indicated by the arrow forces into close contact with the interior of a. In the
tube of which Fig. 3A is a section, there is no packing groove, and the convolutions
are closer to each other.
The machine shewn in Figs. 1 and 2 consists of a base A on which are fixed
bearings B for a revolving mandril C, and bearings D and E for countershafts F
and G. On the mandril Care the fast and loose pullies c e¹ which receive a driving
strap from any suitable motor, and a pulley c² which by means of a crossed strap
drives a pulley g on the shaft G. A pinion g' on the shaft G gears with a wheel f
on the shaft F, driving this shaft at a slow speed as compared with the speed of the
mandril. As the size of the mandril has to be varied for making tubes of various
sizes, the pullies c² and g have to be varied to maintain the proper relation of the
velocities of C and F for operating as will presently be explained. On the shaft F.
is fixed a drawing drum H, the circumference of which is covered with leather or

page_text: on
fabric and a leather or other flexible strap h fixed at its ends passes over about half
the circumference of H. In a frame K fixed on the base A are mounted three pairs of
rollers the upper rollers in sliding bearings which can be simultaneously depressed
by screws geared together and turned by the hand wheel k. As the middle screw
revolves in a direction opposite to that of the other two screws it is threaded to a
different hand. The rollers in the frame K are so grooved on their peripheries as
to corrugate a metal strip passing between them to the desired form such as is
indicated in Fig. 3, the first pair of rollers, those to the left being such as to begin
the corrugation, the middle pair to deepen it, and the third pair to complete or nearly
complete it. There is also in a frame L a fourth pair of rollers exactly fitting the
finished form of corrugation of the strip and guiding it towards the mandril
which it is wound. This mandril, which is of the size required for the internal
diameter of the tube, projects through a stationary plate or headstock M on which
are fixed three holders N1 N2 N3 each fitted with a slide carrying a roller n' n² n³
which by means of an adjusting screw can be advanced towards or drawn back
from the mandril C. Each of the rollers n' n² n³ is grooved on the periphery to
fit the corrugated strip forming the tube and is set slightly at an angle to correspond
with the helical obliquity of the strip as it is wound on the mandril. Also while
the roller n' is in the plane of the guide rollers in L, the holder N2 of next roller n*
is set by packing under it or otherwise a little farther away from the face of M and
the holder N3 of the third roller n³ is set still farther from the face of M, so as to
suit the pitch of the helix forming the tube. A stiff blade T is fixed in such a
position that its end enters the deep corrugation of the strip as indicated by the
dotted lines in Fig. 3.
The machine operates in the following manner: The metal strip S being passed
between the rollers in K is wound two or three times round the drawing drum H
and held thereon by the band put on above it. As H revolves it draws the strip S
through the rollers in K and delivers it corrugated through between the rollers
in L to the mandril C between it and the first roller n', whence the strip passes
under n² and n³. Owing to the relative positions and the obliquity of the
rollers n n n³ the strip S, as it is wound, is caused to take a helical form being
delivered off from the end of the mandril C as a tube with its convolutions
interlocked.
The blade T has the effect of forcing the limb c of the strip to take a position
parallel to d, thus effectually interlocking the successive convolutions. When it is
desired to make the tube with a thread of packing material in the groove of b, this
thread p is drawn from a reel P and led through eyes e to be guided in between the
one convolution and the next.
In some cases, especially when the strip which has to be corrugated to form the
tube is of considerable strength I employ a drum H of double width and arrange
two sets of the corrugating rollers K side by side. I pass the strip through the
first set of the rollers K, then several times round the drum H and back over guide
pullies to pass through the next set of rollers K and again to H. I also in some
cases, employ a longitudinally sliding mandril C, which, as it revolves, advances
with the tube being wound on it, the front end of the tube being clamped to it.
When the mandril has thus advanced its full length, the machine is stopped, the
tube is unclamped from the mandril which is then drawn back, and the part of
the tube last formed being now clamped to the end of the mandril, the machine
goes on winding another length of tube on the mandril, when the operation is
repeated.
As flexible metallic tubes have already been made by coiling helically a strip
of metal corrugated in such a manner that the successive convolutions interlock
with one another, I make no general claim to the manufacture of such tubes, nor
to rendering them tight against leakage by the introduction of a thread of packing
material between their convolutions. Nor do I claim generally the use of a mandril
with winding rollers pressing the corrugated strip around it.

page_text: Having particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. In a flexible metallic tube consisting of interlocked convolutions of helically
wound corrugated metal strip, so forming the corrugations that a portion of one,
convolution can move to and fro as a piston within a cylindrical. portion of
the next convolution, thus securing tightness against leakage, substantially as
described.
2. A machine for manufacturing flexible metallic tube substantially as herein
described with reference to the accompanying drawings.
Dated this 29th day of May 1891.
ABEL & IMRAY,
Agents for the Applicant.