IMPROVE- MENTS RELATING TO UNDERGROUND CONDUCTORS FOR ELECTRICAL DISTRI- BUTION
Year: 1882

page_text: LETTERS PATENT to Thomas John Handford of 42 Southampton Buildings
in the County of Middlesex Patent Agent for an invention of "IMPROVE-
MENTS RELATING TO UNDERGROUND CONDUCTORS FOR ELECTRICAL DISTRI-
BUTION." A communication to him from abroad by Thomas Alva Edison of
Menlo Park in the State of New Jersey United States of America.
PROVISIONAL SPECIFICATION left by the said Thomas John Handford
at the Office of the Commissioners of Patents on the 21st August 1882.
THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County
of Middlesex, Patent Agent, "IMPROVEMENTS RELATING TO UNDERGROUND CON-
DUCTORS FOR ELECTRICAL DISTRIBUTION." A communication to me from abroad
by Thomas Alva Edison of Menlo Park in the State of New Jersey United States
of America
It has been proposed heretofore in laying the conductors for a multiple arc
system of electrical distribution, to connect the intersecting conductors at each
crossing of two streets at four points by running them into four junction boxes
located at the corners of the blocks or squares, the positive conductors being in this
way all connected together, and likewise all the negative conductors, the whole
forming a double net-work of intersecting and connected conductors. Each tube
was run into a separate box near each corner and a fusible conductor or "safety
catch" placed in the line of one or each conductor.
The object of the present Invention is to arrange and connect the conductors at
the intersection of two streets in a more convenient manner making them more
accessible for repairs of connections, replacement of "safety catches," or for testing
purposes.
For
This is accomplished by connecting the conductors of the eight pairs of conductors
at each street intersection, and locating the "safety catches" at one point.
this purpose the eight tubes carrying the insulated conductors are run to the centre
of the street intersection such tubes being bent to a curve for this purpose, and
there enter a single box in which the positive conductors are connected together as
[Pri

page_text: well as the negative conductors, and in which a fusible conductor or "safety catch”
is placed in the line of each of the positive or negative conductors or both.
The box used is preferably made in two parts, secured together by bolts, the
lower part having vertical slots which when the parts are put together form
apertures to admit the tubes, each aperture being of a size sufficient to admit two
tubes. A, box would ordinarily have four of these apertures, admitting eight pairs
of conductors, two pairs from each street. Some boxes however would be provided
with an additional aperture to admit a tube containing the conductors of a feeding
circuit. Or at a place where one street enters another without crossing it, only three
openings would be used. In order to prevent the admission of moisture through
these apertures the box is filled to a point above them with an insulating substance
which is poured in while in a semi-liquid condition and allowed to cool and
harden.
The box is provided with two covers an inner one which fits tightly and is
sealed so as to prevent the admission of moisture, and an outer one which is. loose
so as to be readily removed.
The ends of the conductors are exposed within the box, and to the end of each
is attached a metal "riser" which extends up to a point above the insulating
compound and nearly to the top of the box. Here are placed two metal rings or
plates one above the other. To one of these are connected all the "risers " from
the positive conductors and to the other all those from the negative conductors.
The connections from the "risers" to the plates or rings are made through metal
strips. Preferably the strips running to the upper ring are of copper and the
others of lead, though this arrangement may be reversed, or if desired both sets of
connecting strips may be of lead. Those lead strips serve as "safety catches" they
being of such a size that they will fuse or burn out should an abnormal current be
allowed to pass in the circuit.
In order to support the lower ring in case all the lead strips should be destroyed
at once, supports are provided consisting of blocks or bars of suitable insulating
material such as hard rubber, which mechanically connect the two rings.
"
The "risers are each made in two parts one or both of them being slotted
while a bolt passes through the slot or slots so that the "riser" is adjustable
vertically and can also be placed at an angle. They are so constructed because
the conductors sometimes enter the tube at a slight deviation, either vertical or
horizontal, from a straight line, and it is then necessary to adjust the "risers' SO
that their ends will reach the proper point for connection with the rings.
"
The strips which connect the "risers", with the rings are also made longitudinally
adjustable as also are the insulating supports which connect the two rings. By so
constructing all these parts, the nice and perfect fitting which would otherwise be
necessary is avoided.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas John Handford in the Great Seal Patent Office on the
20th February 1883.
THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex Patent Agent "IMPROVEMENTS RELATING TO UNDERGROUND CON-
DUCTORS FOR ELECTRICAL DISTRIBUTION " A communication to me from abroad
by Thomas Alva Edison of Menlo Park in the State of New Jersey, United States
of America.
It has been proposed heretofore in laying the conductors for a multiple arc
system of electrical distribution, to connect the intersecting conductors at each
crossing of two streets at four points by running them into four junction boxes
located at the corners of the blocks or squares, the positive conductors being in this
way all connected together and likewise all the negative conductors the whole
forming a double network of intersecting and connected conductors. Each tube
was run into a separate box near each corner and a fusible conductor or "safety
catch" placed in the line of one or each conductor.
The object of the present Invention is to arrange and connect the conductors at
the intersection of two streets in a more convenient manner making them more
accessible for repairs of connections, replacement of "safety catches
" or for testing
purposes.
This is accomplished by connecting the conductors of the eight pairs of conductors
at each street intersection, and locating the "safety catches" at one point. For
this purpose the eight tubes carrying the insulated conductors are run to the centre
of the street intersection, such tubes being bent to a curve for this purpose and
there enter a single box in which the positive conductors are connected together as
well as the negative conductors, and in which a fusible conductor or "safety
catch" is placed in the line of each of the positive or negative conductors or both.
The box used is preferably made in two parts secured together by bolts the
lower part having vertical slots which when the parts are put together form
apertures to admit the tubes each aperture being of a size sufficient to admit two
tubes A box would ordinarily have four of these apertures admitting eight pairs
of conductors two pairs from each street. Some boxes however would be provided
with an additional aperture to admit a tube containing the conductors of a feeding
circuit. Or at a place where one street enters another without crossing it, only
three openings would be used. In order to prevent the admission of moisture
through these apertures the box is filled to a point above them with an insulating
substance which is poured in while in a semi-liquid condition and allowed to cool
and harden.
The box is provided with two covers, an inner one which fits tightly and is
sealed so as to prevent the admission of moisture and an outer one which is loose
so as to be readily removed.
The ends of the conductors are exposed within the box and to the end of each
is attached a metal riser which extends up to a point above the insulating compound
and nearly to the top of the box. Here are placed two metal rings or plates one
above the other. To one of these are connected all the risers from the positive
conductors and to the other all those from the negative conductors. The
connections from the risers to the plates or rings are made through metal strips.
Preferably the strips running to the upper ring are of copper and the others of lead
though this arrangement may be, reversed or if desired both sets of connecting
strips may be of lead. These lead strips serve as "safety catches" they being of

page_text: such a size that they will fuse or burn out should an abnormal current be allowed
to pass in the circuit.
In order to support the lower ring in case all the lead strips should be destroyed
at once supports are provided consisting of blocks or bars of suitable insulating
material such as hard rubber which mechanically connect the two rings.
The risers are each made in two parts, one or both of them being slotted while a
bolt passes through the slot or slots so that the riser is adjustable vertically and
can also be placed at an angle. They are so constructed because the conductors
sometimes enter the tube at a slight deviation, either vertical or horizontal, from a
straight line and it is then necessary to adjust the risers so that their ends will
reach the proper point for connection with the rings.
The strips which connect the risers with the rings are also made longitudinally
adjustable as also are the insulating supports which connect the two rings. By so
constructing all these parts the nice and perfect fitting which would otherwise be
necessary is avoided.
And in order that the said Invention may be perfectly understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the accompanying sheet of drawings the same letters of
reference indicating corresponding parts in all the figures.
Figure 1 of the accompanying drawings is a diagramatic view of a street inter-
section, showing how the conductors and central junction box are arranged.
Figure 2 a horizontal section of the box.
Figure 3 a plan of the outer cover:
Figure 4 a vertical section of the box showing a part of the internal connections
the latter being in elevation.
Figure 5 a plan of one of the strips which connect the risers with the rings.
Figure 6 a section of a part of one of the risers: and
Figure 7 a view of one of the insulating supports with its connections.
A, A, are tubes each containing a pair of conductors one p being positive and
the other n, negative. A' is a tube containing conductors p. n of a feeding circuit.
The tubes are all bent at points a, a, (see figure 1) so that they meet the box B
which is in the centre of the street intersection.
The box consists of two parts C, D, (figure 4) preferably bolted together.
Slots E E in the side of the lower half D, of the box form apertures through
which the tubes pass. The box shown has five of these apertures but it may have
four or only three as before explained.
The conductors n, p, extend beyond the ends of the enclosing tubes and the box
is filled to a point above the tube openings preferably about as far as the line 1, 2
of figure 4 with a suitable insulating compound, which is poured into the box when
soft and allowed to cool and become hard.
To the exposed ends of the tubes are attached risers b and 6¹ the risers b'being
attached to the positive conductors p and the risers b¹ to the negative conductors n.
The risers extend up above the insulating substance and nearly to the top of the
box. Here are placed two rings one N to which all the risers b₁ are connected
and the other P to which are connected the risers b. The connections of the
risors 6 with the ring P are made through lead strips c and those of risers 61 to
ring N through copper strips c¹. The rings N, P, are mechanically connected
by means of insulating blocks or bars d.
The risers b, b¹, connecting strips c, c², and insulating supports d, are all made
adjustable. They are shown in detail in figures 5, 6 and 7. Referring to Figure 5,
the connecting strip c is provided with a slot e through which passes a screw f into
the ring P, the other end being secured to the top of the riser b, By this
construction the strip c is made adjustable longitudinally, and also can be readily
removed if it is desired to break connection, or to replace a safety catch. In
Figure 6 is shown a riser b made in two parts one having a slot g through
which passes a screw stud h provided with a nut i, so that the riser may be
lengthened or shortened or turned to an angle if desired. By this means, should

page_text: the tubes enter the box at an angle, the risers may be so adjusted as to still reach
just the desired point. The insulating supports d (see Figure 7) are each attached
by a screw to the lower ring P but at their upper ends each is attached to a
separate piece ; which has a slot k receiving a bolt which extends up from the
ring N and has a nut m. Thus the position of the support is adjustable so that if
the two rings cannot be placed in exactly the proper relative position the
mechanical connection between them can still be made.
The box is provided with two covers an inner one F and
the bottom of the cover F is a circular rib o which rests in a
on the interior of the box, being further secured by bolts
placed in the joint to prevent the admission of moisture.
bole s is formed in the centre of the cover.
it
an outer one G. On
groove in a flange H
and red lead being
A screw threaded
The outer cover G rests on a shoulder within the tube; and has a knob t by which
may be raised. When it is desired to reach the interior of the box, the outer cover
is removed, the nuts removed from the bolts r and the cover F raised, this being
effected by inserting a screw threaded rod in the hole s. Where considerable force
is required to do this a convenient method is to place a cross strap across the top
of the box, having a hole through which passes the screw threaded rod which enters
the hole s, a nut being placed above such cross strap so that by screwing down the
said nut the rod and cover are raised. The hole s should be kept filled with tallow
when not in use to prevent rusting.
8
The top of the outer cover G as shewn in Figure 3 is corrugated by ribs and
raised letters or otherwise so as to provide a secure foot hold for horses such cover
being level with the surface of the street.
All the permanent connections within the box are soldered together but the
removable and adjustable connections all have their contacting surfaces gold-plated
to produce a non-oxidizable contact.
Having now described and particularly ascertained the nature of the said Invention
and the manner in which the same is or may be used or carried into effect I would
observe in conclusion that what I consider to be novel and original and therefore
claim as the invention secured to me by the hereinbefore in part recited Letters
Patent is :-
In a system of underground conductors for electrical distribution, the combination
of the conductors at the intersection of two streets, with a single central box in
which all the connections are made, substantially as hereinbefore described.
In witness whereof I the said Thomas John Handford have hereunto set my
hand and seal this nineteenth day of February in the year of our Lord
one thousand eight hundred and eighty three.
TH J HANDFORD (L.S.)