Improvements in and in the Manufacture of Drawn Tubes. for Making Cycle Frames, and for other Purposes. requiring Lightness combined with Strength.
Year: 1896

page_text: Date of Application, 1st Oct., 1896
Complete Specification Left, 3rd Aug., 1897-Accepted, 1st Oct., 1897
PROVISIONAL SPECIFICATION.
Improvements in and in the Manufacture of Drawn Tubes. for
Making Cycle Frames, and for other Purposes. requiring
Lightness combined with Strength.
I, DAVID HARRY SHUTTLEWORTH-BROWN, of Belle Vue Villa, South Wimbledon, in
the County of Surrey, England, Engineer do hereby declare the nature of this
invention to be as follows:-
Take a short section of ordinary drawn tube as now made for a Specific purpose (a
stay, for example), slit it, open it out, flatten it-the sectional edge of the metal is
now, roughly speaking, a long parallelogram.
Draw this on paper on an enlarged scale. Now, at about th (preferably more) of
the vertical depth of the parallelogram draw a dotted line from end to end-on this
dotted line erect, say, equilateral triangles of such magnitude that the top line of the
parallelogram is at half their altitude, or thereabouts.
A Maundril, the periphery of which could be represented by the upper sides of these
triangles, containing angles slightly more acute owing to the application of the
figure to a circular (or other) form-will produce the draw plate that will make the
given tube stronger for the same weight of metal.
The way to make a tube equally strong, with less metal (i.e. and lighter) is to
begin by selecting a less vertical dimension for the parallelogram.
The tubes are drawn more easily than plain tubes-this will surprise the
operator.
It has hitherto been regarded by the most experienced Tube-drawers to be
impossible to draw such a tube as is here described, and it would appear that the
reason for this is, that the force necessary to draw the tube would, by any known
method, be so great as to pull it to pieces; whereas, by the method here, for the first
time, adopted such a tube is easier to draw than even an ordinary plain tube ;-
moreover, the oxide of iron, which collects on the surfaces of such plain tubes, attaches
itself to the draw-holes, rips and scratches the external surfaces of the tube as it
passes through the hole, renders the drawing more difficult, and necessitates the
frequent cleaning of the draw-holes, is by this method cut up and easily disposed of
without stopping the process-it is easily embedded in the corrugations.
Immagine that a patch of refractory, fibreless matter, such as iron rust, has
accumulated on the surface of an ordinary plain tube which is about to be passed
through the draw plate; there is a practically incompressible maundril or triblet
within the tube, and the paries of the tube will be diminished in thickness to the
extent of the diminution effected by the draw-hole, the least diameter of which is less
than the external diameter of the tube which has to pass through it; the fibres of the
tube, which are nearest to the draw-hole, will be elongated in passing through
the draw-hole, but the rust upon the surface of the tube has no such ductile fibres as
the clean tube, therefore, in ordinary circumstances its mass is crushed into the body
of the paries of the tube by the pressure of the draw-hole, it thus breaks the external
fibres of the tube, and, parting company with those fibres that have gone through the
hole, attaches itself to the draw-hole, on the interior periphery of which it forms a

page_text: blemish (a blemish on the side of its conical section) which thereafter scratches, cuts
and disfigures the surface of the tube before it can pass out of the drawhole.
How great is the crushing pressure which forces the rust into the body of the
paries of the tube can well be imagined, and, the corrugation, as it has hitherto been
attempted, it may be, for ornamental purposes, but never for giving strength and
lightness to cycle-tubes, has been so effected that the internal teeth of the draw-hole
have pushed back, or crushed, cut, broken or displaced the external fibre of the tube
in a somewhat similar way to that here ascribed to the rust; hence it arises that
advantages of strength and lightness, by this method so easily obtained, have been,
although obvious, neglected by Tube-drawers in the Cycle industry.
Now, it may be assumed that practice, during many years, has led to the adoption
of a diameter of tube, and thickness of paries, duly proportioned to the ascertained
strength of the metal, and the strain it has to bear in any part of the Cycle frame,
thus, the following generalities are all that need to be cited:-
(a) The circle combines the greatest area with the least periphery.
(b) Any departure from a circular section of tube will diminish stiffness, or increase
weight.
For these reasons, corrugation by means of undulating the paries, increases weight
without increasing area.
Again, to corrugate the interior of a tube with small corrugations presents practical
difficulties when combined with similar external corrugations, and the work is not
open to inspection; this last fact condemns it.
It remains, therefore, that, for "round" tubes, the most economical form is that in
which the interior is a true circle, and the exterior, only, is so corrugated as to thicken
the paries without increasing its weight. In order, however, to make it possible to
draw such a tube, it is necessary to preserve a very exact relationship between the
diameter of the triblet, the diameter of the tube to be corrugated, and the greatest
and least diameters of the finishing end of the hole in the draw plate, and, besides
these points, it is desirable to observe with great nicety the angles of the cone, both
of the drift which is to corrugate the hole in the draw plate, and of the hole in
the draw plate to be corrugated thereby..
In order to drive the corrugating drift into the soft draw-hole, without breaking
'the drift, it is desirable to press it in by hydraulic power.
If the drift be turned, say, a quarter turn, whilst the corrugations are being cut in
it, the draw-hole will be rifled, as it were, when finished, but the drift cannot, of
course, be pressed into the hole unless it be free to swivel during the time it is being
pressed into the draw hole which it is corrugating.
The effect of drawing a tube through a corrugated hole which is rifled is, that
strength is added to the tube in another direction, i.e. the corrugations can enter
deeper into the paries without fear of the tube being too thin at the bottom of the
corrugations; and angles more acute than those of the equilateral triangle may be
cut into the drift.
Hereunder are sundry particulars of an experimental tube which it would have.
been impossible to draw, had not all the necessary dimensions been so predetermined
that the superficial fibres of a plain tube were thrown up laterally by the teeth in the
corrugating hole, so that the surface of the plain tube was, so to speak, ploughed like
a field-the tube has not been under the microscope, but it is imagined by the
undersigned that a section of the corrugated tube would shew a vertical line
descending from the apex of each ridge to about the original radius of the plain tube;
that the teeth of the corrugating draw hole entered the paries of the plain tube,
passing first into, or between superficial fibres, and, whilst depressing, and pushing
aside the material here, threw it up into the furrows in the draw hole, in such a
manner that the vertical line would represent two portions of the original surface of
the plain tube, face to face.
The extreme diameter of this tube, finished, was 0-1307 inch 3.32 millemetres,
true to the roth mm., when measured in the micrometer, to the diameter
predetermined.

page_text: To arrive at this result, a Draw-plate, 3" thick, was made, having a plain hole, on
the finishing side, 9 Imperial Standard Gauge = 0.144 in. = 3.658 mm. diameter,
another smaller hole 9 I.S.G., say, 0016 in., another hole 10 L.S.G. = 0.128 in.
= 3.251 mm., and a plain hole, to be corrugated, 0.1307 in. = 3.32 mm. diam: at
the large end, tapering to 0.128 in. = 3.251 mm. diam: at the small end, as drilled
to receive the drift-it should be said that the mouth of this hole was 0-285 in
= 7.25 mm. and tapered down so that the length of that portion of the hole which
was taper drilled to receive the corrugations from the drift was 0-073 in.
= 1.84 mm.
-this last dimension was made rather small for fear of breaking the drift; this was
not a necessary precaution.
Now, a drift was made, so tapered that, in a length of 20 mm., its diameter
diminished from 3.75 mm. to 3 m., and having 144 corrugations cut, longitudinally,
with a cutting tool ground to an angle of 60° at the point-thus, the furrows in the
drift in the tube-the teeth in the draw-plate, each contained an angle of 60°;
therefore, the ridges in the drift-in the tube-the furrows in the draw-plate would
4 right angles) than 608.
each be less (? by-
144
It has been said that the finishing end of the plain hole, to be corrugated, in the
draw-plate had a diameter of 0.128 in. 3.251 mm.; this last is the same diameter
as the hole for finishing the plain tube before corrugation-to this it will be necessary
to recur, after stating that:-
Two triblets were made, each, 1 metre long, and 0116 in. 2.946 mm. diam:
and it was estimated that the plain tube, after passing through the draw plate, might
expand, from 3251 mm. to 326 mm. diam: and that its bore might expand,
from 2.946 mm. to
Difference
2-956 mm. nearly
0.304 mm
Therefore, the thickness of the plain tube, i.e. the paries of the tube was, before
corrugating, 38 I.S.G. =0.152 min.
The drift, corrugated, was inserted in the hole, plain, tapered from 3-32 mm. down
to 3.251 mm.
Now, 332 min. was intended to be the extreme diameter of the corrugated tube,
ie. from apex to apex of the ridges; and 3.2 mm. was intended to be its diameter
from furrow to furrow; and 3.251 min. was intended to be the diameter of the plain
tube passing through the previous plain hole, pressed against its triblet.
Thus, the diameters are:-ridge
3.32 mm.
plain tube 3.251
Diam of ridge exceeds plain tube, by 0.069 mm.
Diam of plain tube 3.251 mm
do. furrow 3.2
Diam of plain tube exceeds furrow, by 0.051 min.
Therefore, the altitude of the ridge, 000 mm., above the surface of the plain tube,
is greater than 25 mm., the depression of the furrow, below the surface of the plain
tube; but, was it not stated that the angles of the furrows in the drift-in the tube
of the teeth in the draw-plate contained 60°, and that the ridges in the drift-in
the tube-the furrows in the draw-plate contained angles of less than 60° ?
Thus, the hard metal of the drift penetrates, with its ridges, deeper into the soft
draw plate than the burr, displaced by them, has to sink into the shallower but wider
furrows in the drift.
Then, when the plate is hardened, the ridges of its draw-hole are broader, and of
less altitude than its furrows, its ridges displace more tube-metal than its furrows will
contain in the same relative altitude and the difference, if any, between the
content of, the ridge in the plate, and the furrow in the plate, the latter being the

page_text: greater, is the measure, so to speak, the small meastire of longitudinal compression,
back pressure, that converts the plain tube into the corrugated tube.
The two triblets were lapped up to the same diameter, viz., 2.946 min., one of these
was the core of the finished plain tube, diameter 3.251 mm.-the finishing end of the
corrugating hole, plain, i.e, before corrugating it by means of the drift, was made
3.251 mm. diam and a triblet 2.946 mm. was used for the core when corrugating
the tube-thus, the triblet of the plain tube, and the triblet of the corrugated tube
had the same area, and also, the finishing end of the draw-hole which made the plain
tube had the same area as the finishing end of the draw-hole which made the
corrugated tube; the ouly difference being that due to the action of the surface
of the drift in denticulating the hole, without either increasing or diminishing its
area to any appreciable or measurable extent.
It is owing to this method of determining before hand that there should be no
material decrease in the area of metal in the paries of the corrugated tube, as
compared with the plain tube, before corrugating, that a tube, which it has hitherto
been considered impossible to draw, was drawn with greater facility than when
reducing plain tubes by the ordinary gradations to arrive at a finished size-and it
is owing to the determination beforehand that there should, on the contrary, be
no material increase in the area of metal, that the finish of the corrugated tube
is so perfect in the completeness of the ridges, to their very tips.
The altitude of the triangles, ridges, or corrugations made (in and) on the surface
of the 38 I.S.G. paries of the plain tube was 0.06 mm., and the circular distance
between the tips of the ridges, of the corrugations, the apices of the triangles,
was very nearly 0.07 mm.
Dated this 1st day of October 1896.
D. H. SHUTTLEWORTH-BROWN.
Improvements in and in the Manufacture of Drawn Tubes for
Making Cycle Frames, and for other Purposes requiring
Lightness combined with Strength.
I, DAVID HARRY SHUTTLEWORTH-BROWN, of Belle vue Villa, South Wimbledon, in
the County of Surrey, England, Engineer, 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 :-
Take a short section of ordinary drawn tube as now made for a specific purpose (a
stay; for example) slit it, open it out, flatten it-the sectional edge of the metal is
now, roughly speaking, a long parallelogram.
Draw this on paper on an enlarged scale.
Now, at about 4th (preferably more) of the vertical depth of the parallelogram draw
a dotted line (see drawing) from end to end-on this dotted line erect, say, equilateral
triangles of such inagnitude that the top line of the parallelogram is at half their
altitude, or there abouts.
A Maundril, the periphery of which could be represented by the upper sides of these
triangles, but containing angles slightly more acute-owing to the application of the
figure to a circular (or other) form will produce the draw-plate that will make the
given tube stronger for the same weight of metal.
The way to make a Tube equally strong, with less metal (i.e., and lighter) is to
begin by selecting a less vertical dimension for the parallelogram.
The tubes are drawn more easily than plain tubes-this will surprise the operator.
It has hitherto been regarded by the most experienced Tube-drawers to be

page_text: impossible to draw such a tube as is here described, and it would appear that the
reason for this is, that the force necessary to draw the tube would, by any known
method, be so great as to pull it to pieces; whereas, by the method here, for the first
time, adopted and set forth such a tube is easier to draw than even an ordinary plain
tube;-inoreover, the oxide of iron, which collects on the surfaces of such plain tubes,
attaches itself to the draw holes, rips and scratches the external surface of the tube as
it passes through the hole, renders the drawing more difficult, and necessitates the
frequent cleaning of the draw holes, is by this method cut up and easily disposed of
without stopping the process-it is easily embedded in the corrugations.
Imagine that a patch of refractory fibreless matter, such as iron-rust, bas accumulated
on the surface of an ordinary plain tube which is about to be passed through the draw-
plate; there is a practically incompressible maundril or triblet within the tube, and
the paries of the tube will be diminished in thickness to the extent of the diminution
effected by the draw-hole, the least diameter of which is less than the external
diameter of the tube which has to pass through it; the fibres of the tube, which are
nearest to the draw-hole, will be elongated in passing through the draw-hole, but the
rust upon the surface of the tube has no such ductile fibres as the clean tube, therefore,
in ordinary circumstances its mass is crushed into the body of the paries of the tube by
the pressure of the draw-hole, it thus breaks the external fibres of the tube, and, parting
company with those fibres that have gone through the hole, attaches itself to the
draw-hole on the interior periphery of which it forms a blemish (a blemish on the
side of its conical section) which thereafter scratches, ents and disfigures the surface of,
and weakens the tube, before it can pass out of the draw-hole.
How great is the crushing pressure which forces the rust into the body of the
paries of the tube can well be imagined, and, corrugation, as it has hitherto been
attempted, it may be, for ornamental purposes, but never for giving strength and
lightness to Cycle-tubes, has been so effected that the internal teeth of the draw-bolo
have pushed back, crushed, cut, broken or displaced the external fibre of the tube in
a somewhat similar way to that here ascribed to the rust; hence it arises that
advantages of strength and lightness, by this method so easily obtained, have been,
although obvious, neglected by Tube-drawers in the Cycle industry.
Now, it may be assumed that practice, during many years, has led to the adoption
of a diameter of tube, and thickness of paries, daly proportioned to the ascertained
strength of the metal, and the strain it has to bear in any part of the frame; thus,
the following generalities are all that need to be cited-
(a) The circle combines the greatest area with the least periphery.
(b) Any departure from a circular section of tube will diminish stiffness or increase
weight.
For these reasons, corrugation by means of undulating the paries, increases weight
without increasing area.
Again, to corrugate the interior of a tube with small corrugations present practical
difficulties when combined with similar external corrugations, and the work is not
open to inspection; this last fact condemns it.
It remains, therefore, that, for round tubes, the most economical form is that in
which the interior is a true circle, and the exterior, only, is so corrugated as to
thicken the paries without increasing its weight.
In order, however, to make it possible to draw such a tube, it is necessary to
preserve a very exact relationship between the diameter of the triblet, the diameter
of the tube to be corrugated, and the greatest and least diameters of the finishing
end of the hole in the draw-plate, and, besides these points, it is desirable to observe
with great nicety the angles of the cone, both of the drift which is to corrugate the
hole in the draw-plate, and of the hole in the draw-plate to be corrugated thereby.
In order to drive the corrugating drift into the soft draw-hole, without breaking
the drift, it is desirable to press. it in by hydraulic power.
If the drift be turned, say, a quarter turn, whilst the corrugations are being cut
in it, or if the drift cutter be turned, the draw-hole will be rifled, as it were,
when finished; but the drift cannot, of course, be pressed into the hole unless it be

page_text: free to swivel during the time it is being pressed into the draw-hole which it is
corrugating.
The effect of drawing a tube through a corrugated hole which is thus rifled is,
that strength is added to the tube in another direction,. i.e., the corrugations can
enter deeper into the paries without fear of the tube being too thin at the bottom of
the corrugations; and angles more acute than those of the equilateral triangle may
be cut into the drift.
Hereunder are sundry particulars of an experimental tube which it would have
been impossible to draw, had not all the necessary dimensions been so predetermined
that the superficial fibres of a plain tube were thrown up laterally by the teeth in
the corrugating hole, so that the surface of the plain tube was, so to speak, ploughed
like a field--the tube has not been under the microscope, but it is imagined by the
undersigned that a section of the corrugated tube would shew a vertical line
descending from the apex of each ridge nearly down to the original radius, or the
external surface of the plain tube; that the teeth of the corrugating draw-hole
entered the paries of the plain tube, passing first into, or rather between, superficial
fibres, and whilst simultaneously depressing and pushing aside the material here,
threw it up into ridges filling the furrows in the draw-hole, in such a manner that
the vertical line would represent two portions of the original surface of the plain
tube, face to face.
The extreme diameter of this tube, finished, was 0.1307 inch = 3.32 millimetres,
true to m., when measured in the micrometer, to the diameter predetermined.
In the Drawings-triblet, b = bore, furrow, hhole, 8 = surface and
J= ridge.
To arrive at this result, a Draw-plate 3" thick, was made, having a plain hole, on
the finishing side, No. 9 Imperial Standard Gauge 0.144 in. = 3.658 mm.
diameter, and another smaller hole 9 I.S.G., say, 0-016 in. + 2 less diameter, and
another hole 10 I.S.G. = 0.128 in. 3.251 mm., and a plain hole, to be corrugated,
0-1307 in. 3.32 mm. diam. at the large end, tapering to 0-128 in. = 3.251 mm.
diam at the small end, as drilled to receive the drift-it should be
said that the mouth of this hole was 0.285 in. 7.25 mm. and tapered
down, so that the length of that portion of the hole which was taper-drilled to
receive the corrugations from the drift was 0.073 in. = 1.84 mm.-this last dimension
was made rather small for fear of breaking the drift; this was not a necessary
precaution.
Now, a drift was made, so tapered that, in a length of 20 mm., its diameter
diminished from 3.75 mm. to 3 inm., and having 144 corrugations cut, longitudinally,
with a cutting tool ground to an angle of 60° at the point-thus the furrows in
the drift in the tube-the teeth in or rather of the draw-hole, each contained an
angle of 60°; therefore, the ridges on the drift-on the tube-the furrows in the
draw-hole would each be less by 4 right angles ÷ 144 than 60°, say (60-)° =
571°
It has been said that the finishing end of the plain hole, to be corrugated, in
the draw-plate, had a diameter of 0.128 in. 3.251 mm. at the finishing end; this
last is the same diameter as the hole for finishing the plain tube before corrugation
-to this it will be necessary to recur after stating that:-
Two triblets were made, each 1 metre long, and 0.116 in. = 2.946 mm. diam: and
it was estimated that the plain tube after passing through the draw-plate, might
expand, from 3-251 mm. to 3.26 mm. diam: and that its bore might expand from
2-946 min. to 2.956 mm., nearly.

page_text: The drift, corrugated, was inserted in the hole, plain, tapered from 3.32 mm.
down to 3.251 mm.
Now, 3.32 mm. was intended to be the extreme diameter of the corrugated tube,
i.e., from apex to apex of opposite ridges; and 3.2 mm. was intended to be its
diameter from furrow to furrow; and 3-251 mm. was intended to be the diameter of
the plain tube passing through the previous plain hole, pressed against its triblet.
Thus, the diameters are: -ridge
3:32 mm.
Therefore, the altitude of the ridge, 6 mm., above the surface of the plain
tube, is greater than 1 mm., the depression of the furrow, below the surface of
the plain tube; but, was it not stated that the angles of the furrows in the drift-
in the tube-of the teeth in the draw-hole contained 60°, and that the ridges
on the drift on the tube-the furrows in the draw-hole contained angles of less
than 608.
Thus the hard metal of the drift penetrates, with its ridges, deeper into the soft
draw-plate than the burr, displaced by them, has to sink into the shallower but
wider furrows in the drift.
Then, when the plate is hardened, the ridges of its draw-hole are broader and of
less altitude, comparatively, than its furrows, its ridges displace more tube-metal
than its furrows will contain-in the same relative altitude-and the difference, if any,
between the content of, the ridge in the plate, and the furrow in the plate, the
latter being the greater, is the measure, so to speak, the small measure of
longitudinal compression, by pressure, that converts the plain tube into the
corrugated tube.
The two triblets were lapped up to the same diameter, viz., 2.946 mm., one
of these was the core of the finished plain tube, diam: 3.251 mm. the finishing
end of the corrugating hole, plain, i.e., before corrugating it by means of the drift,
was made 3.251 mm. diam: and a triblet 2.946 mm. was used for the core when
corrugating the tube-thus the triblet of the plain tube, and the triblet of the
corrugated tube had the same area, and also, the finishing end of the draw-hole
which made the plain tube, had the same area as the finishing end of the draw-
hole which made the corrugated tube; the only difference being that due to the
action of the surface of the drift in denticulating the hole, without either increasing
or diminishing its area to any appreciable or measurable extent.
It is owing to this method of determining, beforehand, that there should be no
material decrease in the area of metal in the paries of the corrugated tube, as
compared with the plain tube, before corrugating, that a tube, which it has hitherto
been considered impossible to draw, was drawn with greater facility than when
reducing plain tubes, by the ordinary gradations, to arrive at a finished size-and it
is owing to the determination, beforehand, that there should, on the contrary, be
no room for any material increase in the area of metal, since such increase would
be impossible, that the finish of the corrugated tube is so perfect in the complete-
ness of the ridges, to their very tips-for the accurate execution of the work I am
indebted to Mr. R. W. Munro of King's Cross Road London.
The altitude of the triangles, ridges, or corrugations made (in and) on the surface
of the 38 I.S.G. paries of the plain tube was 0.06 mm., and the circular distance
between the tips of the ridges of the corrugations, the apices of the triangles, was
very nearly 0-07 mm.
J

page_text: Invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. Drawn tubes for Cycle frames and other purposes requiring lightness combined
with strength, corrugated longitudinally, substantially as described.
2. The same corrugated spirally, by turning the drift, or drift cutter, and swivelling,
substantially as described.
3. The adaptation of areas in the triblets and the draw holes of the plain and the
corrugated tubes respectively, substantially as described.
Dated this 31st day of July A.D. 1897.
D. H. SHUTTLEWORTH-BROWN.