ELECTRIC CABLES AND IN MANDRELS FOR MANUFACTURING THE SAME
Year: 1884

page_text: "
I, RICHARD SOLOMON WARING of Pittsburg, County of Allegheny, State of
Pennysylvania United States of America Electrical Engineer do hereby declare
the nature of my Invention for "ELECTRIC CABLES AND IN MANDRELS FOR
MANUFACTURING THE SAME and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement:-
The first part of my Invention relates to electric cables and is illustrated in
Figures 1 and 2 of the accompanying Drawing in which:
Figure 1 is a perspective view of my improved cable.
Figure 2 is a transverse sectional view of the same.
This part of my Invention relates to certain improvements in compound electric
cables and in general terms it consists of a cable having a soft metal body of
rounded form with passages therethrough 'enclosing insulated conducting wires,
such wires being arranged at equal intervals around the solid soft metal core, or
centre as hereinafter more fully described and claimed.
In making compound cables of the class to which my Invention relates, it is.
desirable that the wires be in as close proximity as possible and at the same time
secure continuous unbroken walls of enveloping metal enclosing each of the several
wires, and that the greater part or bulk of metal in the body or covering should be
outside of or surrounding the exterior of the wires. Continuous and unbroken
walls between and enveloping the wires are required for the double purpose of
preventing electrical induction, and excluding from the insulating material all trace
of moisture or other agencies liable to deteriorate or injure its electrical insulating
properties. For this latter purpose it is also desirable that the centre or core of
the cable should be filled solid, by preference with the soft metal of the body,
because a tubular passage in the centre or core is liable to admit moist air, and
such moisture, condensing on the, metal wall, may find its way through minute
pores or "blow-boles" to the insulating material and thereby supply the requisite
elements for developing a weak but troublesome electric or electrolytic action
detrimental to the best working of the cable. These minute openings are much
more liable to appear on inner than upon outer surfaces, owing to the difficulty of
making complete adhesive union in the soft metal by such supply and pressure as
can be forced between and around wires arranged around the centre, and this
difficulty is greatly increased when attempt is made to form a tubular passage in
the centre or core.

page_text: In order to meet the requirements and secure the advantages above noted I make
my improved cable A as follows:-
A body a by preference of lead (though other soft ductile metal or equivalent
alloy may be employed) is given a rounded exterior form by means of the die-
opening of the cable press. This body is made solid and unbroken throughout its
mass, with the exception of passages a¹ formed by the wire-holding mandrel of the
press, which passages enclose each an insulated conducting wire c. I prefer to
include three such wires in the cable, arranged at equal intervals around the
central core of metal a² such core being integral with and connected by unbroken
walls, with the outer body of metal covering. These wires may be described as .
occupying relative positions corresponding to the angles of an equilateral triangle,
the axis of the cable as a whole and of such triangle, being co-incident. This
feature of triangular arrangement is provided with reference to facilitating flow of
lead into the spaces between wires so that lead entering between wires from
opposite sides may completely fill the centre and uniting under pressure, may form
complete unbroken inner walls of covering for each and all the wires.
In this arrangement three wires may be grouped so closely as to require but
little more lead to cover them safely than is ordinarily required for one wire.
This affords great advantage and economy in manufacture, since the cost of lead
forms a very large part of the total cost of such a cable. This grouping of wires
also affords an advantageous method of making cables containing a large number
of wires, by arranging them in groups of three, each group being substantially a
reproduction of the cable herein shown and described except that its body of
covering is formed as a part of and integral with others, thereby uniting such
groups into one common whole.
The second part of my Invention relates to mandrels, for manufacturing lead
armored electric cables and is illustrated in Figures 3 to 6 of the Drawing in which
Figure 3 is an end view of my improved mandrel looking upon the nipples or
point of the same.
Figure 4 is a longitudinal sectional view, the plane of section being indicated by
the line X, X. Figure 5.
Figure 5 is a transverse sectional view taken in the plane of the line X1 X¹
Figure 4.
Figure 6 is a side elevation of my improved mandrel.
Electric cables of the class to which the present Invention relates are composed,
of a body of soft metal, lead being preferred for this purpose, through which are
a number of small passages, enclosing the insulated conducting wires. It is an
essential condition in this class of cables that cach wire should be enveloped by
close-fitting continuous or intact walls of lead covering in order not only to
neutralize or prevent the evil effects of electrical induction in companion wires, but
also to completely seal each wire and prevent access thereto or to its insulating.
covering, of moisture or other injurious agencies.
These results alone considered may be secured by comparatively light lead walls
dividing one wire from another as shown at a¹ between the wires c Figures 1 and 2.
But in order to afford requisite protection from other external injuries and obtain
sufficient body of metal covering to make the cable durable, it is important that
the exterior wall or body of covering should be of considerably greater thickness
than is required for the inner walls between wires.
The purpose of my present Invention is to provide for making a cable having
such features of construction, and in general terms it consists of a mandrel having
wire passages through the same, with longitudinal grooves in the outer face
between wires extending to the point with narrow passages or channels cut across
the point between passage openings as hereinafter more fully described and
claimed.
I have shown in the Drawings, a mandrel designed to make a three-wire cable
Figures 1 and 2, certain features of advantage being secured thereby, which make
such form and number preferable. My Invention may however be applied in part,
J

page_text: at least, to mandrels providing for a greater number of wires and therefore I do not-
wish to limit its application to the specific form and number shown.
1
1
My improved mandrel is formed of a tapering body of iron steel or other suitable:
metal, C having in its base end a threaded socket c¹ for making attachment to the
tubular core bar D of the press. Within or beneath the socket c¹ is an axial:
chamber C registering with the tubular passage in the core-bar. From the base.
of this chamber to the tapered point of the mandrel body are drilled three separate.
holes or passages c² the relative positions of which correspond to the angles of an
equi-lateral triangle. Along the tapering exterior sides of the body C are formed
grooves e¹ which extend to the point along the lines between wire-passages c². :
Also at the extreme point, narrow and comparatively shallow channels are cut
across the end, connecting the points or extremities of opposite grooves e¹ between
the openings to the wire-passages.
The grooves el direct the flow of lead into the space between wires, and the
channels e afford openings into which the lead passes laterally from each groove e¹
and unities forming complete, pipe-like enclosures for each wire before or as the
lead leaves the mandrel point and comes in direct contact with the wires.
It will be observed that the relative positions of the three wires combined with
the exterior, side-grooves e¹ afford exposure of almost the entire surface of the
mandrel around each wire to direct contact and pressure of lead as is applied to or
pressed upon the exterior surface leaving but comparatively small amount of inner
surface that is, directly facing the companion passages., Also by the shallow cuts
or channels e provision is made for forming the lead into tube-like enclosures
before it leaves the mandrel, thereby preventing undue pressure of lead upon the
wire, which, if too great would cause injury by stripping off or injuring the
insulating covering of the wires. Also by these features of construction the wire-
passages may emerge at the point of the mandrel in close proximity, the walls
surrounding the passage-openings being light or thin and supported as against
pressure, except at the extreme point. The wires may therefore be placed in close
proximity in the cable A Figures 1 and 2 and still direct channels are afforded for
filling in the metal a¹ between the wires.
The thickness of metal covering forming the exterior of the cable may be
determined in the usual way by the size and adjustment of the die-opening
through, which the wires pass on leaving the mandrel and within which the lead
is applied to the wires as practiced in the art.
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 ·
First. An electric cable having a body of lead or equivalent soft metal or alloy,
solid in its centre or core and enclosing insulated conducting wires in passages
formed through such body at intervals around its solid core substantially as
set forth.
Second. An electric cable having a body of lead or equivalent soft ductile metal
or alloy; solid in its centre or core and enclosing three insulated conducting wires
each within its appropriate passage, such wires having positions at equal intervals
around the solid axis or core of the body, substantially as set forth.
Third. An electric cable having a body of lead or equivalent soft, ductile metal
or alloy having passages therethrough at intervals around and in close proximity
to its solid centre, the thickness of metal wall between wires being less than the
thickness of covering surrounding such wires, substantially as set fourth.
Fourth. An electric cable having a body a of lead or equivalent soft ductile
metal or alloy such body enclosing three separate insulated conducting wires c
arranged at equal intervals around and in close proximity to the solid core a² of
the body, the thickness of metal walls between wires being less than the thickness
of exterior metal covering substantially as set forth.
Fifth. A mandrel C for a cable press having a tapered body with separate wire-
passages therethrough and longitudinal grooves e¹ extending between the lines of

page_text: wire passage to the point, and having shallow cuts or channels e in the end
connecting the grooves between the openings of the wire passages substantially as
set forth.
.
Sixth. A mandrel C for a cable press having a tapered body with three wire
passages therethrough, such passages emerging at the point in positions
corresponding to the angles of a triangle and having grooves e¹ formed longitudinally
in the exterior surface between wire-passages substantially as set forth.
.
Seventh. A tapering mandrel C for a cable press, having three wire passages
therethrough emerging at the point in close proximity and in positions corresponding
to the angles of a triangle, with longitudinal grooves el extending along the
exterior surface of the mandrel between wire-passages to the point, and cuts or
channels e crossing the point between the passage openings substantially as set
forth.
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