Improvements in Tools for the Manufacture of Tubes and other Cylinders.
Year: 1891

page_text: Date of Application, 3rd Oct., 1891
Complete Specification Left, 3rd Aug., 1892-Accepted, 1st Oct., 1892
"
PROVISIONAL SPECIFICATION.
Improvements in Tools for the Manufacture of Tubes and other
Cylinders.
I, GEORGE HOOкнAм of Nos. 7 & 8 New Bartholomew Street Birmingham
Manufacturer, do hereby declare the nature of this invention to be as follows:-
I will first describe the form of tool that I prefer. This is essentially similar in
construction to the ball-bearing with lateral adjustment in use for velocipedes.
Such a tool may be fixed on the fore-end of the spindle of a hollow-spindle lathe &
rotated. The lateral adjustment is 'screwed up so that the inner circle touched by
the balls when pressed home against their collars is smaller than the tube to be
operated on by the amount by which it is required to reduce the size of the tubo.
The tube with a solid mandrill fitting it is passed through from the back of the
lathe-head & is seized in front by a grip & drawn through at a regulated speed by
chain, screw, or other gear. As it is drawn through it is rolled down elongated &
condensed by the action of the rotating tool. Instead of a mandrill travelling with
the tube, I may use a fixed mandrill or plug in a manner well understood. Instead
of balls I may use rollers rotating in bearings or rolling on a collar or collars in
which case the rollers should be tapered on the face first operating on the tube &
cylindrical at the part last operating. When I use the ball-bearing arrangement
first described it is obvious that as a result the surface of the tube will be marked
with a shallow helical groove. I may afterwards remove this by rollers such as I
have last described or by skew-rollers such as are used for shaping shafting, either
with or without a mandrill or plug, or by a process of ordinary drawing by dies.
In the case of cylinders such as are used for storing compressed gases the processes
may be performed on the hot metal; but in the case of tubes ordinary rolling is
generally more economical at this stage. Instead of using a lateral adjustment for
my ball bearing tool I may place the balls in solid collars using a series of tools one
following the other. A similar ball bearing tool with lateral adjustment may be
used for the internal rolling or expansion of tubes & cylinders either with or
without increasing the length. In all cases I find it advisable to keep the balls
from touching each other by metal partitions, which are all fixed to a collar
rotating with the balls, each partition not quite filling the space between any two
balls, & having preferably a certain amount of spring. I grind away a portion of one
of the collars, so that once in each revolution of the balls each ball is freed from
pressure.
:
By the action of the tools of the various kinds above described, tubes & cylinders
having special qualities are produced. By the ordinary process of drawing the
grain of the metal is set in a longitudinal direction, & if a piece is cut from a tube
the metal will be found very strong in this direction but quite weak & brittle if
bent transversely but with tubes manufactured by my process the metal will be
found equally tough in all directions. This results from the whole of the metal
being equally worked: & a further result is, that whereas in drawing steel tube, for
instance, an elongation of at most 25 per cent. without annealing is all that is
practicable. I can by my process draw & elongate the same steel 500 per cent.
without injury to the metal. I may also by use of the lateral adjustment of the
balls draw tube thicker in one part than another, or thicker at each end than in the
middle. Such tubes are useful for various purposes as in bicycle construction & for
boiler tubes, or without varying the thickness of the metal, depressed & raised parts
may be produced.
1001

page_text: COMPLETE SPECIFICATION.
Improvements in Tools for the Manufacture of Tubes and other
Cylinders.
I GEORGE HOOKHAм of Nos. 7 and 8 New Bartholomew Street, Birmingham,
Manufacturer do hereby declare the nature of my invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement:—
My invention consists of the improvements in tools for the manufacture of
metallic tubes and other hollow metallic cylinders hereinafter described and illus-
trated in the accompanying drawings.
I will first describe the form of tool which I prefer. This is essentially similar
in construction to the ball bearing with lateral adjustment in use for velocipedes.
Such a tool may be fixed on the fore end of the spindle of a hollow lathe spindle,
and rotated. The lateral adjustment is screwed up so that the inner circle touched
by the balls when pressed home against their collars is smaller than the tube to
be operated upon by the amount by which it is required to reduce the size of
the tube.
The tube with a solid mandril fitting it is passed through from the back of the
lathe head and is seized in front by a grip and drawn through at a regulated speed
by chain, screw or other gear. As it is drawn through it is rolled down, elongated
and condensed by the action of the rotating tool.
Instead of a mandril travelling with the tube I may use a fixed mandril or plug
in a manner well understood.
Instead of balls I may use rollers rotating in bearings or rolling on a collar or
collars, in which case the rollers should be tapered on the face first operating on
the tube and cylindrical at the part last operating. When I use the ball bearing
arrangement first described, it is obvious that as a result the surface of the tube will
be marked with a shallow helical groove. I may afterwards remove this by rollers
such as I have last described or by skew rollers such as are used for shaping
shafting either with or without a mandril or plug, or by a process of ordinary
drawing by dies.
I have found in practice that by polishing the surfaces of the rollers, or rolls
especially at the parts last operating upon the metal of the tube, such parts being
left nearly cylindrical or being rounded to a very long radius, a highly-polished
surface is produced on the tube, so much so that in the case of bicycle tube, for
instance, the tubes may be nickel-plated without further treatment. A result
approximately the same may be produced with large polished balls say of from
1 inch to 2 inches diameter. These finishing or polishing processes are applicable
to tubes produced otherwise than by the rotating tools herein described.
In the case of cylinders such as are used for storing compressed gases, the
processes may be performed on the hot metal; but in the case of tubes, ordinary
rolling is generally more economical at this stage.
Instead of using a lateral adjustment for my ball bearing tool I may place the
balls in solid collars using a series of tools one following the other.
A similar ball bearing tool with lateral adjustment inay be used for the internal
rolling or expansion of tubes and cylinders either with or without increasing the
length. In all cases I find it advisable to keep the balls from touching each other
by metal partitions which are all fixed to a collar rotating with the balls, each
partition not quite filling the space between any two balls.
In practice I have found that balls are chiefly applicable to very thin tubes but
that rollers properly shaped have a much wider application. Generally tubes
whose sides do not exceed in thickness one fifteenth part of the diameter of the
tube may be drawn down to thinner gauges and smaller diameters and left smooth
and polished by rollers, if certain precautions are observed. For instance the

page_text: advancing angle of the tapered cylindrical roller should not much exceed 7 degrees,
otherwise a burr may be thrown up in advance of the tool which when rolled-in
produces a bad surface.
If too many rollers are employed, the tube is set tight on the mandril; if too few
the metal loops between each pair of balls, are injured by repeated bending.
The proper number of rollers may generally be found by the rule that the
distance between the points of pressure of any two adjacent rollers should not be
more than about 8 times, or less than about 4 times the thickness of the tube. 'No
exact rule can, however, be given, only the general rule that if the tube gets too
loose on the mandril the number of rollers should be increased and vice versa.
Figure 1. of the accompanying drawings represents partly in vertical section and
partly in elevation, a rotating tool for the drawing or manufacture of metallic tubes
and hollow metallic cylinders constructed according to my invention;
Figure 2 represents a cross section of the same taken on the line a. b. Figure 1.
Figure 3 represents the acting-parts of the tool detached from the holder and
Figure 4 represents an end elevation and cross section of the cage or holder and
the series of steel cylindrical rollers carried by it.
The same letters of reference indicate the same parts in the several figures of the
drawings.
"
The said tool consists of the tubular holder c screwed internally having a face
plate d. by which the tool is fixed to the fore end of the hollow spindle of a
lathe for rotating the tool; or the tool may be rotated in any other convenient
manner.
In the said internally screwed holder c are two adjusting rings or collars ef.
screwed on their edges for taking into the said screwed holder. Between the rings
or collars e f. the steel cylindrical rollers g, gare confined, the said rollers being
carried by the cage or holder h. the sides of which are bound together by the cross
bars i. separating the rollers. The cage h. is provided at each end with radial
slots k. k. (see Figure 4.) in which the axes of the steel rollers work, the said slots
and axes keeping the said rollers at the proper distance apart.
It will be seen that the said rollers are arranged in the said cage so closely as
nearly to be in contact with each other, the axial space enclosed by the said rollers
forming the draw-hole or eye of the drawing-tool.
The screwed rings or collars e. f. besides confining the rollers in their places also
serve to laterally or radially adjust them for increasing or diminishing the size of
the draw hole enclosed between them. This is effected by making in the opposed
or inner faces of the adjusting rings or collars e. f. conical grooves l. 1. and making
the ends of the steel rollers conical the conical ends of the rollers and the conical
grooves being inclined at the same angle as seen in Figure 1.
By this arrangement the screwing of the outer adjusting ring or collar e. in one
or other direction in the tubular holder c. causes its inclined groove l. to bear upon
the inclined ends of the rollers and either force the said rollers inwards radially and
diminish the size of the drawhole or permit of the rollers separating radially and
increase the size of the drawhole.
The outer adjusting disc or collar e. is rotated in the holder so as to adjust its
position therein by inserting a studded lever in opposite holes made in its 'outer
face.
•
The rings or discs e f. are interchangeable, that is, either may serve as the front
or adjusting disc.
•
In drawing a tube or hollow cylinder by the use of the rotating tool represented,
the size of the drawhole of the said tool having been adjusted by means of the
outer collar or ring e., the tube to be operated on, fitted on a mandril, is passed
through the drawhole of the tool from the back of the lathe head and the end of
the tube and mandril is seized in front by a grip and drawn through the tool at a
regulated speed by means of a draw-bench or screw or other gearing the lathe
spindle carrying the tool being at the same time slowly rotated. By the action of

page_text: the rotating tool the tube as it is drawn through it has its thickness of metal
reduced and its length increased and the metal condensed or consolidated.
After the tube has been once drawn through the tool the rollers are pressed
inwards so as to diminish the size of the draw hole for a second drawing by
screwing in the outer adjusting disc or ring e. and similarly for subsequent
drawings.
In the drawing Figure 1. the rollers of the tool are represented in their fully
pushed in positions for forming a drawhole of the size of the smallest tube which
the tool is capable of drawing.
The tube being drawn may travel with the mandril or the tube may be drawn
over a fixed mandril or plug when using my improved rotating drawing tool.
Figures 5. and 6. represent sections taken in planes at right angles to each other,
of another rotating drawing tool constructed according to my invention, in which
tool, steel spheres or balls are employed in place of conical ended cylindrical steel
rollers.
Figure 7 represents in front elevation and cross section, the cage or holder in
which the spheres or balls are held and separated.
In the said Figures 5. and 6. the balls or spheres are marked m. m. and the cage
is marked p. and the separating bars of the cage for keeping the balls at the proper
distance apart are marked p'. It will be seen by reference to the drawing that the
cage or holder consists of a flat disc which is held between the adjusting rings e. f,
the said holder being provided with radial enlargements at p² by which the balls in
the holder are separated.
The other parts of the tool are the same as corresponding parts of the tool first
described and are marked with the same letters of reference.
The action of the conically grooved adjusting collars or rings e. f. upon the
spheres for increasing or diminishing the size of the drawhole of the tool is the
same as that described with respect to the tool-containing rollers.
In Figures 8. and 8^ I have shown a set of rolls for polishing the tube. The tube
may either be pulled through while the rolls revolve, or if the rolls are set slightly
askew they will feed the tube through, as is well understood. For polishing only
the rolls need not be made so long as in Figure 8^; as shown, they may be used for
straightening also, and in that case only the part last operating on the tube need be
highly polished. The tube is drawn on a hard mandril (not shown in the drawings)
which fits it.
.By the action of the tools of the various kinds before described and illustrated,
tubes and hollow cylinders having special qualities are produced. By the ordinary
process of drawing, the grain of the metal is set in a longitudinal direction and if a
piece is cut from a tube so drawn, the metal will be found very strong in this
direction, but. quite weak and brittle if bent transversely; but with tubes manu-
factured by the use of the tools described the metal will be found equally tough in
all directions.
I may
also by the use of the lateral adjustment of the rollers or balls draw
tubes thicker in one part than another, or thicker at each end than in the
middle.
Such tubes are useful for various purposes as in bicycle construction and for
boiler tubes; or without varying the thickness of the metal, depressed and raised
parts may be produced.
At Figure 9 I have shown a piece of tube with thick ends. In order to produce
this a piece of tube having throughout the thickness, of which the ends of the
finished tube are desired to be, is introduced into one of my rotating draw tools
already described and illustrated.
At the desired distance from one end the balls or rollers are pressed into the tube
by means of the collar e. and the tube drawn through the rotating tool the desired
distance; and it may thus be drawn backwards and forwards through the tool, the
collar being set up at each draw till the required thinning of the middle portion o

page_text: the tube is effected. If only one end of the tube is desired to be left thick, an
adjusting tool is not necessary, successive non-adjusting tools being employed.
Having now particularly described and ascertained the nature of my invention
and the manner in which the same is to be performed I declare that I claim
as my invention of "Improvements in tools for the manufacture of tubes and other
cylinders":―
First. In the manufacture of tubes and like articles a rotating drawing tool with
conical ended cylindrical or nearly cylindrical rollers the said rollers being so
mounted in bearings or partitions rigidly connected together that the rollers shall
rotate freely but out of contact with one another substantially as and for the
purposes described, reference being made to Figures 1. 2. 3. and upper part of
Figure 4.
Secondly. In the manufacture of tubes and like articles in the cold a rotating
drawing tool with spherical or nearly spherical balls, the said balls being separated
by partitions rigidly connected together so that the balls shall rotate freely but out
of contact with one another substantially as and for the purposes described, reference
being made to Figures 5. 6. and 7.
Thirdly. In the process of finishing the manufacture of tubes and like articles
cold where a smooth or bright surface is desired the use of a rotating drawing tool
with smooth or polished rollers or balls substantially as and for the purposes
described and illustrated.
Fourthly. In the process of finishing the manufacture of tubes and like articles
the use of smooth or polished drawing rolls substantially as and for the purposes
described and illustrated in Figures 8 and 8+.
Fifthly. In the manufacture of tubes with sections of unequal thickness as in
Figure 9. or of other than cylindrical form a rotating drawing tool with rollers or
balls so arranged as either to reduce the thickness of the metal in parts or to
depress it in parts substantially as and for the purposes described and illustrated in
the accompanying drawings.
Dated 3rd day of August 1892.
W. T. WHITEMAN,
Agent for the Applicant.