Improvements in Machinery for Bending Tubes.
Year: 1892

page_text: Date of Application, 19th Nov., 1892
Complete Specification Left, 19th Aug., 1893-Accepted, 28th Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in Machinery for Bending Tubes.
1, ROBERT MELVIN MCDOUGALL, of 86 Dale Street, Glasgow, in the County
of Lanark, North Britain, Coppersmith 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 :-
This invention relates to improvements in machinery for bending tubes.
The object of my invention is to bend tubes to any required angle without the
necessity for filling the tubes with filling material such as lead and to produce a
machine which is an improvement upon existing machines in that it is simpler, has
fewer rollers and the work turned out is superior.
In the carrying out of my invention I employ grooved rollers, so mounted
together that all three rollers, which is the number I employ, are always in contact
in any position of the tube that is to say during the whole process of bending the
tube and in the making of any kind of bend, a special object of my said invention
being to preserve the circular form of the tube at the point where it leaves the
rollers.
The three rollers are mounted horizontally upon a table, in contact, and in a
triangular arrangement. The one roller is mounted in fixed bearings, the other
two rollers being mounted in movable bearings working in grooves in the table,
the said grooves being concentric to the fixed roller. All three rollers are geared
together, the fixed roller being the driving roller, the necessary power being
imparted to it by a worm and worm wheel or the equivalent of such, from any
convenient arrangement of shaft or belt. The connecting gearing of the wheels
may consist of a pinion keyed upon the vertical spindle of the fixed roller the said
pinion gearing with pinions keyed upon the spindles of the two movable rollers.
The concentric adjustment of the two movable rollers may be effected by
connecting their spindles by means of links, with the end of an adjusting screw
held in position by a nut mounted on a fixed bracket and advancing the two
movable rollers nearer to or further from each other so as to bring them more or
less in a line with the fixed roller, by rotating the nut by any convenient hand
wheel or lever.
The machine being set in motion, the straight tube is inserted between the
grooved rollers and the movable rollers are advanced by the adjusting screw to
the necessary position relative with the fixed roller to give the bend required to
the tube. In this manner a short length of tube can be bent or the required bend
or curve may be given to produce a coil of tube or pipe.
When bending a tube to a short radius I may disengage one of the movable
rollers and use the one movable roller only, in order to reduce the liability of such
a tube to flatten whilst being bent over the fixed roller.
I may make the groove of the fixed roller deeper than the grooves of the
movable rollers, to prevent the liability of the tube to flatten whilst the tube is
being bent over the fixed roller.
My said machine may also be mounted vertically as well as horizontally.
Nawamba 1002

page_text: COMPLETE SPECIFICATION.
Improvements in Machinery for Bending Tubes.
I, ROBERT MELVIN MCDOUGALL, of 86 Dale Street, Glasgow, in the County
of Lanark, North Britain, Coppersmith, 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 :-
This invention relates to improvements in machinery for bending tubes. The
object of my invention is to bend tubes into coils, or to any required angle, without
the necessity for filling the tubes with filling material such as lead or rosin; said
machine being an improvement upon existing machines for this purpose, that it is
simpler, has fewer rollers, and the work turned out is superior than hitherto.
In carrying out my invention, as illustrated in side elevation and plan, Figures 1
and 2 respectively of the accompanying drawings, I employ three grooved
rollers A, A and A' mounted on a table or frame work B in such a manner that
the said rollers are always in contact with each other, in any position of the tube
during the bending process, the arrangement being such that the tube is bent
without filling and the circular form of the tube, especially at the point where it
leaves the rollere, is preserved.
The three rollers A, A', A', are mounted horizontally upon the table B in a
triangular arrangement as shown, that is to say, the roller A is mounted in fixed
bearings formed in the table B, and the other two rollers A' A', are mounted in
moveable bearings which work in segmental slots or grooves b, formed in the
table B and which are concentric to the fixed roller A. The said rollers are
geared together by means of spur wheels a and are driven through the medium of
the roller A by the worm and worm wheel or other gearing C mounted underneath
the table B, the necessary power being obtained through the medium of a belt and
pulley arrangement D, from any convenient motor.
In order that the machine may be set to give the desired bend to the tube, I
connect the two moveable rollers A' and A² to each other, by means of links E, the
other ends of which are connected to the end of an adjusting screw f' in such a
manner that on the said screw being manipulated the rollers A' and A', are
advanced nearer to or further from each other, so that they are brought more or
less in line with the fixed roller A. The adjusting arrangement consists of a
sliding block which works in a fixed bracket f¹ of the table, the said block f
being connected to the end of the screw f³, on which works a nut f', said nut ƒ³
being connected to a suitable operating handle or lever G, in such a manner that
on the said handle G being operated by hand or other power the rollers A¹ and A³
are moved.
**The rollers A, A' and A³, are so constructed that their grooves are deeper than
a semi circle, so as to prevent the tube from being flattened during the bending
operation. Also if desired, I may make the groove of the fixed roller A, deeper
than those of the moveable rollers so as to further prevent the tube from being
flattened. The screw arrangement, may if desired, be controlled by hydraulic
.
pressure or worm gear.
The action of the machine is as follows:-After having set the machine in
motion, the operator takes the straight, or other piece of tube to be bent, and inserts
it between the grooved rollers, and advances the moveable rollers, by means of the
screw arrangement, to the necessary position relative with the fixed roller, so as to
give the required bend to the tube; in this manner a short length of tube can be
bent, or the required bend or curve may be given to the tube. Also if desired a
coil of tube or pipe may be made by my apparatus, in which case the necessary
upward spiral formation of the coil is effected by means of a rest or guide in the
form of a roller, lever or other device, mounted in such a manner on the table at a

page_text: point near where the tube leaves the rollers as to press the tube or pipe upwards
and so form the pitch of the coil.
When the tubes are being bent to a short radius, I may disengage one of the
moveable rollers, and allow it to press close up to the centre line of the machine,
that is to say, to remain in the position shown in the drawings, and only use one of
the moveable rollers so as to reduce the liability of the tube or pipe being flattened
whilst being bent over the fixed roller.
My said machine may be so constructed, as to be capable of working either
horizontally or vertically.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1st. The general arrangement, construction, and combination of the various parts,
constituting my improvements in machinery for bending tubes, substantially as and
for the purposes, herein before described and shown in the accompanying drawings.
2nd. In tube bending machines, the arrangement of the three rollers, substantially
as and for the purposes, hereinbefore described and shown in the accompanying
drawings.
Dated this 18th day of August 1893
J. Y. JOHNSON,
115, St. Vincent Street, Glasgow, Applicant's Agent.