IMPROVEMENTS IN "ELECTRIC CABLES
Year: 1884

page_text: COMPLETE SPECIFICATION.
I, THOMAS GILPIN TURNER of the City, County and State of New York, one
of the United States of America, gentleman, do hereby declare the nature of my
invention for IMPROVEMENTS IN "ELECTRIC CABLES," and in what manner tho
same is to be performed, to be particularly described and ascertained in and by
the following statement :—
This invention relates to that class of electric cables in which the conductors are
laid concentrically around a core, and enclosed in a protecting sheath or armor.
The objects of the invention are, first, to so construct the armor that it may be
opened at any point, without rupture of the metal of which it is composed, to
afford access to any one or more of the conductors of the cable, and again closed
and sealed, second, to so arrange the individual wires or conductors of the cable
with relation to an indicator, and to each other, that any one of said conductors
may be readily found, third, to so arrange the conductors and indicator with
relation to the joint or seam of the armor that the indicator and each of said
conductors will pass said seam once in a given distance; fourth, to establish contact
between the core and armor to lessen the effect of induced current; also, to provido
a core which will yield slightly upon the contraction of the surrounding conductors,
also to provide means by which the interstices between the conductors may be filled
with a material which will repel moisture, and finally, minor objects relating to the
laying or use of a cable, which objects will more fully appear hereinafter.
The invention consists in certain novel parts and combinations which will be
claimed in the clauses at the close of this specification.
In the accompanying drawings,—
Fig. 1, is a perspective view of my improved cable.
Fig. 2, is an elevation, partly in section, of the preferred form of core.
Figs. 3, and 4, are details of the cable in cross section.
The core, A, of my cable is a tube or pipe of lead, having, preferably, numerous
perforations, a, in its walls, for the double purpose of rendering the core more
sensitive to lateral pressure, and of affording means by which hot paraffin or other
equivalent substance may be forced into the interstices between the respective
conductors surrounding the core.
Around this core, A, is grouped a number of independent insulated conductors, B,
one of the conductors, B', differing from the others of the group, so that it may be

page_text: readily distinguished and serve as a guide or indicator so that any one of the
conductors of the group may be known from the position it bears with relation to
said indicator.
The difference between the indicator, B', and the other conductors of the cable
may consist in a difference in the insulating material, or in the color of said
material, the main object being to make it readily distinguishable from the other
conductors of the group.
The conductors, B, and B', having been laid closely about the core, A, I apply
a binder or binders, b, to hold them in a fixed position with relation to each other
during the application of the armor, C.
The binder or binders, b, may be of insulating material, such as kerititape, or of
non-insulating material, as is found most convenient; or, as it is desirable to place
the core, A, in metallic contact with the armor, C, I contemplate in some instances
forming the binders of short strips of lead, one end of which is placed between any
two of the conductors, B, and in contact with the core, while the free end of the
strip is wrapped around the grouped conductors so that the armor, when applied,
will be in contact with it.
These lead binders can be quickly and cheaply applied at suitable intervals
during the construction of the cable.
In the event of using other than the lead binders, the indicator conductor, B¹,
may be one having a metallic armor, while the conductors B, may be provided
with any ordinary insulation without armor, it being understood, of course, that in
this instance the binder be so disposed as to permit the indicator, B, to come in
contact with the armor, C, thus establishing contact between said armor and the
core, A. The armor, C, is composed of a ribbon of lead of such width that when
the ribbon is folded around the grouped wires or conductors a surplus of metal will
be left at the meeting edges, which surplus is bent out to form the radial projec-
tions, c. A key, D, of soft metal or solder is interposed between these projections,
and melted to unite them and form a tight joint. This key should be made of
a metal or composition fusible at a comparatively low temperature, in order that it
may be melted without affecting the lead armor, as it will be sometimes necessary
to open the seam formed by the key and projections, c, to connect branch wires, or
for other purposes, and again close said seam when the connection has been made.
I prefer to lay the conductors spirally upon the core, with a pitch of say, one
turn in three feet, as by this means I am enabled to bring each wire of the group
across the seam of the armor in a given distance, so that upon opening the seam
all the wires will be exposed to view, and the required one selected, (its position in
relation to the indicator being known,) and the branch connection made.
It will be seen that the cable herein-described is very simple and can be cheaply
constructed. It is my purpose to construct the cable at the trench or ditch as it is
required, and for this purpose I have devised a portable machine for the purpose,
in which the core is fed forward, the conductors laid spirally thereon, the armor
folded around the grouped conductors, and the key laid and fused.
As the conductors can be spliced at any point during the construction of the
cable, I avoid the necessity of splicing two sections of cable, (which is always
necessary in laying long lines of shop-mado cable,) and also avoid any possible
injury to the armor or insulating coatings of the conductors resulting from the
coiling and un-coiling of shop-made sections.
Having now particularly described and ascertained the naturo of my said
invention and in what manner the same is to be performed I declare that what
I claim is-
1, In a cable the combination of the flexible core, a group of insulated conductors
surrounding said core, (one of which is an indicator,) and an armor having a
longitudinal scam, substantially as set forth.
2, In a cable the combination of the flexible coro, a spirally disposed group of
insulated conductors surrounding said core, (one of which is an indicator) and an
armor having a longitudinal seam as described.

page_text: 3, In a cable the combination of the perforated tubular core, a group of insulated
conductors surrounding said core, and armor enclosing said conductors, and inetallic
binders arranged at intervals and connecting the core with the armor, substantially
as set forth.
4, In a cable the combination of the tubular core, a spirally disposed group of
insulated conductors surrounding said core, (one of which is an indicator) and an
armor consisting of a ribbon of metal folded around said conductors and having its
longitudinal edges united by solder, as set forth.
5, In a cable the combination of the tubular core, a spirally disposed group of
insulated conductors surrounding said core, (one of which is an indicator,) and an
armor consisting of a ribbon of metal folded around the conductors, and having
the outwardly surplus of metal at its edges united by solder interposed between
them, substantially as set forth.
6, The improvement in the art of forming continuous cables which consists in
feeding a group of insulated conductors, (one of which is an indicator,) each having
a separate spool, spirally upon a core, splicing the individual conductors as the
respective spools become exhausted, folding a ribbon longitudinally upon the
conductors as they are laid upon the core and uniting the meeting edges of the ribbon
by solder to form a longitudinal seam, substantially as set forth.
Dated the 20th day of September 1884