An Improved Flexible Core or Coil for use in the Bending of Metal Pipes.
Year: 1889

page_text: Date of Application, 24th Oct.. 1889-Accepted, 30th Nov., 1889
COMPLETE SPECIFICATION.
An Improved Flexible Core or Coil for use in the Bending of
Metal Pipes.
I, HENRY MARTYN BRIGHAM, of 537 Green Avenue, in the City of Brooklyn,
county of Kings and State of New York, United States of America, Lawyer do
hereby declare the nature of my invention and in what manner the same is to
he performed, to be particularly described and ascertained in and by the following
statement and accompanying drawings in which :-
Figure 1 is a section of pipe in which my device has been inserted ready for use,
and shows the tapering of the spring core. Figure 2 is a section of pipe showing my
invention after the pipe has been bent and before the coil or core has been withdrawn
therefrom. Figure 3 shows enlarged cross sections of some of the best forms of wire
out of which my invention may be constructed.
",
Similar letters of reference designate corresponding parts in all of the figures.
designates the spiral coil or core, 6, the metallic pipe into which a has been inserted;
c, the loop of the end of a, by which a is withdrawn; de and fare cross sections of
some of the best forms of wire, out of which my device may be constructed.
In the process of bending metal pipes or tubes, it has been customary to use a
flexible spiral coil or core of wire which is inserted into the pipe, and which although
flexible enough to be easily bent with the pipe into any desired form, still possesses
sufficient strength to prevent the pipe from collapsing.
The best form of wire out of which to construct such a spring coil is that having the
exterior surface flattened, so as to give as large a bearing surface as possible to the
inner surface of the pipe. There should be no sharp edges as they are liable
to cut into the pipe and render it difficult to withdraw the spring when the pipe
has been bent.
But even with this device, it has been found to be very difficult to withdraw the
spring after the pipe is bent. The spring is usually withdrawn by turning it in the
direction which will reduce the diameter of the coil, and then pulling it until the spring
is withdrawn a short distance. In doing this the spring will turn in the pipe and the
coil return to its original form and size. This operation must be repeated several
times before the spring can finally be withdrawn and this process soon weakens
the best spring that can be made and renders the work of removing the coil very
laborious.
My improvement consists in making a spiral core or coil which is slightly less in
diameter at the end which is inserted into the pipe and which is gradually tapered from
the larger to the smaller end.
The advantage of this construction will readily be seen, for when the spring has once
been withdrawn as before described, a short distance, it is then less in diameter than
the pipe at all points where they come in contact with each other, and the spring can
then be removed with little effort.
My invention thus saves the spring and economizes time and labor.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, 1 declare that what I
claim is
I. A tapering spiral coil or core of wire for bending metallic pipe.
II. A tapering spiral coil or core of wire for bending metallic pipe, having the
surface of the wire forming the exterior of the coil somewhat flattened as described

page_text: III. A tapering spiral coil or core for bending metallic pipe, constructed of wire
having a flat or plane surface, on the side forming the exterior of the coil as described
and shown.
IV. A tapering spiral coil or core for bending metallic pipe constructed of wire
having a flat or plane surface, on the side forming the exterior of the coil, and having
the edges of such flat or plane surface rounded off substantially as described and
shown.
Datad this 1 day of October 1889
DUTTON & FULTON,
1, St. James Square, Manchester, Agents for the Applicant.