Improvements in Conduits for Electrical Conductors.
Year: 1895

page_text: Date of Application, 28th Mar., 1895--Accepted, 4th May, 1895
COMPLETE SPECIFICATION.
Improvements in Conduits for Electrical Conductors.
We, JAMES FULTON CUMMINGS, of 51 Lewis Street, Electrical Engineer, and
WILLIAN CLYMEN YAWKEY, of 420 Second Avenue, Manufacturer, both of the
City of Detroit, Michigan, United States of America 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:—
The invention consists in the construction of a conduit for electrical conductors,
especially adapted for interior use. The invention particularly consists in the
construction of a duct or tube, comprising an outer metallic pipe, and an inner
lining of wood or similar material, made in sections arranged in tubular form, and
forced into the outer pipe which acts as a sleeve or binder to hold the lining in
shape, all as more fully hereinafter described.
In the drawings, Fig. 1 is a longitudinal section through a conduit embodying
the invention. Fig. 2 is a cross section thereof, and Fig. 3 is a similar section,
showing a slightly modified form.
In the present state of the art it is old to manufacture what is known to the
trade as armored conduits, and these are usually constructed by inserting into a
metallic tube or pipe, an inner pipe of vulcanized fibre, or similar material. This
construction makes an excellent conduit, but requires in its manufacture the con-
struction of two sets of tubes for every size, one of which must fit exactly into the
other, and being of hard material the fit must be very nice, or else the inner tube
is apt to be displaced.
The invention contemplates a construction which overcomes the objections to the
known constructions and enables us to produce a superior conduit at a very much
less cost.
A represents a metallic pipe, preferably the usual iron gas or water pipe of
wrought iron, lap or butt welded and which preferably is finished with a smooth
interior face. The inner tube or lining is preferably formed as shown in the
drawings, consisting of two semicylindrical sections ab, of wood which can be cut
out in an ordinary wood shaping machine or rabbeting machine.
These sections are preferably alike, each having at one edge a tapering tongue
and on the other edge, a corresponding tapering groove d to effect a mortise and
tenon connection between the meeting of the two sections, when they are arranged
together to form a tube.
After we have formed the sections of our inner tube or joining, we saturate them
with oil or subject them to any well known creosoting process, and force them into
the metallic tube under pressure, so as to make a tight joint between the lining and
the casing or armor.
The wooden sections having considerable elasticity will make a tight fit, when
forced into the iron tube, and will hold the meeting edges of the wooden sections
tightly together.
If desired we may apply cement to the inside of the armor, or to the outside of
the lining before forcing the lining into the armor, and we may also apply cement
to the joint between the sections to prevent the possibility of shrinking, opening a
seam.
Instead of the cement, we may apply a small strip of elastic material between the
edges of the sections, as shown at e, which will be compressed when the lining is
forced in and will expand to take up any possible shrinkage.

page_text: While we have shown and described these modified ways of making our conduit,
we do not desire to be limited to such ways, as we believe we are the first to make
an armored conduit, in which the inner lining or tube was made in sections held
together by being forced into the armor or metal pipe.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
The armored conduit for electrical conductors as herein described and shown.
Dated the Ninth of March 1905
JAMES FULTON CUMMINGS.
WILLIAN CLYMAN YAWKEY.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.