IMPROVEMENTS IN TELE- PHONIC AND TELEGRAPHIC EXCHANGE SYSTEMS, AND IN INSULATING AND MOUNTING THE CONDUCTING WIRES USED FOR TELEPHONIC AND TELEGRAPHIC COMMUNICATION."
Year: 1881

page_text: LETTERS PATENT to John Norcross Culbertson, M.D., of Antwerp, in the
Kingdom of Belgium, and James Wallace Brown, of Upper Kennington Lane,
in the County of Surrey, for an Invention of "IMPROVEMENTS IN TELE-
PHONIC AND TELEGRAPHIC EXCHANGE SYSTEMS, AND IN INSULATING AND
MOUNTING THE CONDUCTING WIRES USED FOR TELEPHONIC AND TELEGRAPHIC
COMMUNICATION."
PROVISIONAL SPECIFICATION left by the said John Norcross Culbertson
and James Wallace Brown at the Office of the Commissioners of Patents on
the 16th April 1881.
JOHN NORCROSS CULBERTSON, M.D., of Antwerp, in the Kingdom of Belgium,
and JAMES WALLACE BROWN, of Upper Kennington Lane, in the County of Surrey.
'IMPROVEMENTS IN TELEPHONIC AND TELEGRAPHIC EXCHANGE SYSTEMS, AND IN
INSULATING AND MOUNTING THE CONDUCTING WIRES USED FOR TELEPHONIO
AND TELEGRAPHIC COMMUNICATION."
This Invention has for its object improvements in telephonic and telegraphic
exchange systems, and in insulating and mounting the conducting wires used for
telephonic and telegraphic communication.
In working the telephonic apparatus it has been found desirable to use complete
metallic circuits, and endeavours have been made to arrange what are known as
central exchange systems to work in this manner, but up to the present time no
satisfactory arrangement has been applied for the purpose.
We effect this object in the following manner :- We employ switch boards of
the ordinary construction with a number of insulated parallel bars, to which
conducting wires leading to the distant stations are attached. At right angles to
these wires are a number of other insulated bars, to which any one or other of the
first mentioned bars can be coupled by the insertion of a metallic peg at a point
where the bars cross one another. One of the cross bars of each switch board is
ordinarily coupled to earth. We connect all the return wires from the distant
stations to this bar, and where a number or series of similar switch boards are used

page_text: we couple together all these bars of the several switch boards by a conducting wire.
Thus the return circuit from all the distant stations will be conveyed through this
wire, and the coupling of the wire from one station to the wire leading to another
station will be effected by shifting a single peg only, that is, one peg for each
station.
In central exchange systems in which complete metallic circuits are not used we
also propose to have a return wire from each station, and to use a central system
of "earths," as in many cases it is found that the "earths" made at the distant
stations are defective, but with central "earths" they are more under supervision,
and can readily be made good.
When a number of insulated conducting wires are used, and are formed into a
cable or bunched together we insulate each conducting wire by surrounding it with
a fibrous coating, which we saturate with glycerine.
In order to protect a number of insulated conducting wires cabled or bunched
together we surround the cable or bunch with asbestos, tape, or tape coated with
asbestos paint.
The advantage of using asbestos or asbestos paint for protecting the insulating
wires is that asbestos is not effected by variations of temperature to the same
extent as other materials heretofore used for this purpose, and for this reason it
better protects the insulation of the wires, and allows the wires being insulated
with cheaper materials.
When suspended wires are used it is frequently advantageous in construction
work to run many wires in the same direction at the same time, but the difficulty
in doing so is that the wires twist or cable together, and considerable time is often
lost in separating them one from the other. To avoid this we confine the wires at
set distances apart oné from another by passing them at intervals through insulating
guard pieces. By keeping the wires appart in this way we are enabled to draw
over many wires at a time from one point of suspension to another, and so avoid
labour and expense. The wires also being kept apart at intervals by the insulating
guards may be placed much closer together than could otherwise be the case so
giving to some extent the advantage of cabled wires, but with better insulation
and of less cost. The insulating guard pieces may each have a hook attached to
them to hook onto a supporting wire so that they may be drawn along this wire,
and the several conducting wires which are held by the guards be readily drawn
over from one point of suspension to another.
The guards may be circular, or rectangular, or of other form, and may have any
desired number of wires passing through them.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Norcross Culberston and James Wallace Brown in the
Great Seal Patent Office on the 15th October 1881.
JOHN NORCROSS CULBERTSON, M.D., of Antwerp, in the Kingdom of Belgium,
and JAMES WALLACE BROWN, of Upper Kennington Lane, in the County of Surrey.
"IMPROVEMENTS IN TELEPHONIC AND TELEGRAPHIC EXCHANGE SYSTEMS, AND IN
INSULATING AND MOUNTING THE CONDUCTING WIRES USED FOR TELEPHONIC
AND TELEGRAPHIC COMMUNICATION."
This Invention has for its object improvements in telephonic and telegraphic
exchange systems, and in insulating and mounting the conducting wires used for
telephonic and telegraphic communication.
In working with telephonic apparatus it has been found desirable to use complete
metallic circuits, and endeavours have been made to arrange what are known as
central exchange systems to work in this manner, but up to the present time no
satisfactory arrangement has been applied for the purpose.
We effect this object in the following manner-We employ switch boards of the
ordinary construction with a number of insulated parallel bars, to which conducting
wires leading to the distant stations are attached. At right angles to these wires
are a number of other insulated bars, to which any one or other of the first
mentioned bars can be coupled by the insertion of a metallic peg at the point where
the bars cross one another.
One of the cross bars of each switch board is ordinarily coupled to earth. We
connect all the return wires from the distant stations to this bar, and where a
number or series of similar switch boards are used we couple together all these
bars of the several switch boards by a conducting wire. Thus the return circuit
from all the distant stations will be conveyed through this wire, and the coupling
of the wire from one station to the wire leading to another station will be effected
by shifting a single peg only, that is, one peg for each station.
At Figure 1 of the Drawings hereunto annexed we have shewn a diagram view
of three switch boards of a central telephonic exchange adapted as above described
for working with complete metallic circuits.
A, B, C, are ordinary switch boards, one of the cross bars d, d', d², of each of which
is connected to earth E in the usual manner; E2 is simply an extension of the earth
strip for the purpose of connecting the return wires of all the circuits F, F'. F2, to
earth, the other half of the circuits as shown being connected to the switch boards in
the usual manner. G is a complete set of telephonic apparatus which is connected to
the switch board A and to earth through E2 and E. The other switch boards have
like apparatus attached to them for the same purpose, that is to call and answer
calls; H, H¹, are connecting wires between the switch boards for the purpose of
extending the circuits through one or more boards; K is a series of plugs or pegs,
which may be shifted to any cross section of the board, as may be necessary to
bring any two subscribers in connection with one another.
In central exchange systems in which complete metallic circuits are not used we
also propose to have a return wire from each station, and to use a central system
of "earths," as in many cases it is found that the "earths" made at the distant
stations are defective, but with central "earths" they are more under supervision,
and can readily be made good.
Figure 2 shews one switch board of a central exchange working with a central
system of earths as above described.
The return wires all have central isolated earths E, 1, 2, 3, 4, 5, 6, 7, 8, as shewn,
also the cross bar or earth strip A of the board shewn is separated from the cross
bar or earth strip of the other switch boards.

page_text: When a number of insulated conducting wires are used and are formed into a
cable or bunched together we insulate each conducting wire by surrounding it with
a fibrous coating, which we saturate with glycerine. In order to protect a number
of insulated conducting wires cabled or bunched together we surround the cable or
bunch with asbestos, tape, or tape coated with asbestos paint.
The advantage of using asbestos or asbestos paint for protecting the insulated
wires is that asbestos is not affected by variations of temperature to the same
extent as other materials heretofore used for this purpose, and for this reason it
better protects the insulation of the wires and allows of the wires being insulated
with cheaper materials.
When suspended wires are used it is frequently advantageous in construction
work to run many wires in the same direction at the same time, but the difficulty
in doing so is that the wires twist or cable together, and considerable time is often
lost in separating them one from the other. To avoid this we confine the wires at
set distances apart from one another by passing them at intervals through insulating
guard pieces. By keeping the wires apart in this way we are enabled to draw
over many wires at a time from one point of suspension to another, and so avoid
labour and expense. The wires also being kept apart at intervals by the insulating
guards may be placed much closer together than could otherwise be the case, so
giving to some extent the advantage of cabled wires, but with better insulation and
at less cost.
The insulating guard pieces may each have a hook or hooks attached to them to
hook on to a supporting wire or wires so that they may be drawn along this wire
or wires, and the several conducting wires which are held by the guards
be readily drawn over from one point of suspension to another. The guards may
be circular, or rectangular, or of other form, and may have any desired number of
wires passing through them.
Figure 3 shews a number of wires stretched between supports and kept separate
by insulated guard pieces A. These insulating guard pieces may, as shewn at
Figure 4, be circular, with perforations to allow the wires to pass through, or they
may be made rectangular, as shewn at Figure 5. In this case they may be made
in sections 1, 2, 3, as shewn, and be clamped or screwed together. Figure 6 shews
a circular guard with hooks attached to it for the purpose previously described.
We claim the several improvements herein described in telephonic and telegraphic
exchange systems and in insulating and mounting the conducting wires used for
telephonic and telegraphic cammunication.
In witness whereof, we, the said John Norcross Culbertson and James
Wallace Brown, have hereunto set our hands and seals, this Twenty
seventh day of September, in the year of our Lord One thousand eight
hundred and eighty one