Improvement in Apparatus for and Process of Bending Tubes and Pipes.
Year: 1887

page_text: Date of Application, 30th Aug., 1887.
Specification Accepted, 28th Oct., 1887
COMPLETE SPECIFICATION.
Improvement in Apparatus for and Process of Bending Tubes
and Pipes.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention, which has
been communicated to me from abroad by James Henry Kelly, of Rochester, New
York, United States of America, Manufacturer, and Charles Henry Broad, of
Rochester, New York, United States of America Machinist, and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement
:-
This improvement relates to the means and process for the manufacture of bent
tubes and pipes in which the bend is made after the tube or pipe has been formed.
Such work has before been done, but the common process has been to fill the tube or
pipe with sand or other filling, hold the same tightly in place, and then produce the
bending either around a form or by hand. The difficulty is that the filling will yield
more or less, and the tube will necessarily flatten and upset or corrugate when bent,
and will frequently break at the bend.
The object in this invention is to bend tubes and pipes so that they will not be
flattened or corrugated at the bend, or break, but will present substantially a true circle
in cross section at all parts of the bend, will be of the same diameter their whole
length, and with the exterior surface smooth and well finished.
In the drawings-
Fig. 1, is a plan view of the apparatus by which the work is done.
Fig. 2, is a side elevation of the same.
Fig. 3, is a central, longitudinal, vertical section.
Fig. 4, is a front elevation of the grooved forming head, the yoke, the grooved die
and connecting parts.
Fig. 5, is a diagram illustrating the method of bending the tube by the rod or
mandrel.
Fig. 6, is an enlarged elevation partially in section, of a piece of bent tube.
Fig. 7, is a cross section of fig. 6.
A indicates a bed, and A¹ a circular head forming a continuation of same said had

page_text: tube or pipe conform when bent, and provided with a half circular groove a, in which
the tube is laid to be bent. B is a clamp resting over the bed, and having a half
circular groove in its under side to receive the top of the tube.
down to hold the tube against end movement by any suitable means.
The clamp is forced
Cis a yoke having straps or bearings, resting and turning on journals c c of the
forming head A', as shown most clearly in Fig. 4. These straps may either be made
separate and attached by screws d d to the yoke, or made an integral part thereof.
The yoke is provided with a handle, by which it is operated.
D is a lever forming the die, the same being pivotted at g in a fork of the yoke so
as to have an independent turning movement therein. It is provided at the top with
a handle h, by which it is operated. Its lower end reaches to the surface of the
forming head A', and it is provided at the bottom with a half circular groove a', which
embraces the upper surface of the tube. The yoke C and die D sweep around the
forming head and are accessory to the bending of the tube by the rod or mandrel, as
hereinafter described. The yoke and the die can be made in one piece and be
operative, forming, in that case, simply a die; but they are preferably made separate to
facilitate the insertion and removal of the tube.
E is a rod or mandrel, through the medium of which the bending is done, and
which is inserted in the end of the tube to be bent, the inner end being carried to the
proper position between the forming head A' and die D, as shown in Fig. 3. The
outer end of the rod rests in a stirrup C, that is pivotted or attached at ii to the sides
of the yoke and turning with it, by which means it is carried around with the yoke
and die. The rod is held to the stirrup by any desired means, that shown in drawing
being a nut K, which screws up on a thread on the rod and thus serves as a gauge to
adjust the rod forward or back to fit its end properly between the forming head and
die. Any other suitable gauge may be used for the purpose. Any other device that
will carry the rod as fast as the die moves around the forming head, or as fast as the
tube is bent, may be used in place of the stirrup.
The operation is as follows:-
The tube is laid in the groove a and clamped in place, and the die D is turned
down so as to embrace it. The rod or mandrel E is inserted in the projecting end of
the tube or pipe so as to bring the inner end of the rod or mandrel in proper position
between the forming head and die, as before described. The yoke C carrying the
die, the stirrup and the rod, is then swung around the forming head as indicated by
the dotted lines in Figs. 2 and 3. The rod E bearing against all sides or faces of the
inside of the tube keeps said sides close pressed against the grooved bed in which the
tube lies, so that it cannot wrinkle or crimp. The rod in that case causes a simul-
taneous drawing and bending movement of the tube around the form, and making the
bend as it progresses coincident with the movement of the yoke, die and stirrup, and
the circular end or head of the rod resting at the point where the bending takes place
forms a core, preserves the circle of the tube, and leaves the tube practically circular
in cross section in all parts of the bend and its entire length. This tube differs
materially from those bent in the ordinary way by having a smooth exterior, and
being of the same diameter the whole extent, nevertheless, by changing the position of
the rod E', the tube can be crimped or ribbed at the bend when desired.
It is not absolutely necessary to the practical working of this invention that a
swinging yoke and die be used; but the work can be done by the rod inserted in the
tube, and properly held and made to sweep around the forming head coincident with
the bending of the tube. A plain straight rod will do the work practically and well,
but to facilitate the operation the rod is preferably made with an enlargement or head
at the inner end where the bending takes place, as shown in the drawings.
By the use of the process above described no filling is required, the bending is
made coincident with the motion of the rod around the form, and is produced by the
rod, and the tube is bent without cracking or breaking at the bend. The tube is
smooth on the outside, circular in cross section at all parts of the bend, and of the
same diameter its whole length. The bend can be made of any desired curve and in
any part of the tube, and without necessarily corrugating the metal; and where sheet

page_text: netal tubes are used the bend can be made without reference to the position of the
eam or joint to the line of the bend.
This machine is specially applicable to bending thin tubing, or sheet metal pipes,
but it is not intended to limit it to such purpose, for all kinds of tubes and pipes
which are capable of being bent can be bent by this machine and process, the only
limit being the strength and stiffness of the rod or mandrel.
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim:
is :-
:-
1st. In an apparatus for bending tubes and pipes, the combination of a form on
which the tube is laid, a clamp for holding the tube, a rod or mandrel for bending the
tube, and a carrier for holding the rod, as specified.
2nd. In an apparatus for bending tubes and pipes, the combination of a form on
which the tube is laid, a clamp for holding the tube, a rod or mandrel for bending the
tube, a carrier for holding the rod, and a die which sweeps around the form, as
set forth.
3rd. The combination of a form on which the tube is laid, a clamp for holding the
tube, a rod or mandrel for bending the tube, a carrier for holding the rod, a die which
sweeps around the form, and a yoke to which the die is attached, as specified.
4th. The combination of a form, a clamp, a rod or mandrel, a die, a yoke, and a
stirrup attached to the yoke, said stirrup serving as a holder for the rod, as specified.
5th. In an apparatus for bending tubes and pipes, the combination, with a form to
which the tube is clamped, of a rod or mandrel attached to a carrier, said rod or
mandrel entering the end of the tube and producing the bend by being drawn around
the form, as set forth.
->
6th. The process herein described of bending tubes and pipes, which consists in
securing the tube or pipe on a form of the shape to which it is desired to have the
tube or pipe conform when bent, inserting a rod or mandrel in the tube or pipe, and
finally giving a simultaneous drawing and lateral movement to the rod or mandrel
around the form, as and for the purpose specified.
7th. The process herein described of hending tubes and pipes, which consists in
securing the tube or pipe on a form of the shape to which it is desired to have the
tube or pipe conform when bent, inserting a rod or mandrel in the tube or pipe, and
resting a die upon the tube or pipe, and finally carrying the rod or mandrel and die
around the forum, as and for the purpose specified.
nul
DAIL JC 1007
ALLISON BROS.,
Agents for the Applicant.