Improvements in Connectors for Electric Conductors.
Year: 1893

page_text: Date of Application, 2nd Nov., 1893
Complete Specification Left, 16th Jan., 1894-Accepted, 3rd Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Connectors for Electric Conductors.
I, HERBERT RUDOLPH KEITHLEY, of 285 Forty-second Street in the City of
Chicago, County of Cook and State of Illinois, United States of America,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to rail bonds or connectors for electrically uniting sections
of electric conductors, such, for instance as railway rails used for conductors in
electric railway systems.
The objects of the invention are, to provide a rail bond or connector which may
be easily and cheaply made and which may be secured firmly and strongly to the
rail ends or other parts to be connected so that it will not loosen under jarring or
strains and which at the same time will have such a large area of contact with the
conductor as to prevent resistance of the passage of the electric current from the
conductor to the connector.
According to this invention the adjacent ends of two railway rails are connected
by the usual fastening devices, the webs being provided with holes extending there-
through. The rail bond consists of a rod, bar or wire having at its ends tubular or
thimble shaped terminals made of proper size for insertion into the holes in the webs
and adapted to closely fit the said holes. The thimbles or heads will be welded, forged
or otherwise formed on the ends of the wire or rod. The connector and its heads
will preferably be made of copper, or other suitable metal may be employed if
desired. Drift pins or plugs are provided which are made somewhat larger in
diameter than the openings or recesses of the tubular heads or thimbles of the
connector, and are adapted to be driven into the said heads or thimbles after the
same have been inserted in the holes so as to expand said heads or thimbles into
contact with the walls of the holes. The drift pins or plugs will preferably be
made somewhat conical on their advance ends so that when driven into the heads
or thimbles they will expand every part of the latter into solid contact with every
part of the surface of the hole in the rail. The said heads or thimbles are provided
with slots or notches at their outer ends to facilitate the entrance of the drift pin
or plug in inserting the same, but these notches are not essential to the operation
of the device.
If desired the hole may be provided with a screw-thread, or a square-shaped
or other tool may be driven into it, or other process used to notch the surface of
the hole before the connector is inserted therein, so as to afford positive engage-
ment of the connector end with the hole and thus avoid possibility of its being
-loosened by strain or vibration. Under ordinary circumstances, however, satis-
factory results are secured when the hole is left smooth, it being obvious that the
driving of the drift pin into the connector head or thimble, in the manner described,
expands the metal of which it is formed against the surface of the hole so as to
exclude all air and moisture and make the joint entirely proof against corrosion,
-oxidation or electrolytic action.
I prefer to make the tubular end or thimble of such diameter that the area of
the surface which is in contact with the main conductor will be equal at least to
seven times the cross sectional area of the wire or rod the result of this construction
being that the resistance to the passage of the electric current through the joint
5.will then be no greater than at any other part of the connector. I prefer to thus
construct the parts for the reason that the relative conductivity of copper and iron
is as seven to one, and in order to reduce the resistance to a minimum in the joint,
where a copper conductor is connected with an iron one, the area of the copper

page_text: surface in contact with the iron should be at least seven times the cross sectional
area of the copper conductor.
It is not necessary that the drift pin or plug should be left within the tubular
head of the connector but it may be a hand tool used to expand the connector head
into the hole of the conductor and then removed.
Dated this 2nd day of November 1893.
1
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant:
Improvements in Connectors for Electric Conductors.,
I, Herbert RUDOLPH KEITHLEY, of 285 Forty-second Street, City of
Chicago, County of Cook and State of Illinois, United States of America,
Engineer, 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 :-
My invention relates to rail bonds or connectors for electrically uniting sections
of electric conductors, such, for instance, as railway rails used for conductors in
electric railway systems.
Objects of the invention are, to provide a rail bond or connector which may be
easily and cheaply made and which may be secured firmly and strongly to the rail
ends or other parts to be connected so that it will not loosen under jarring or strains
and which at the same time will have such a large area of contact with the
conductor as to prevent resistance of the passage of the electric current from the
conductor to the connector.
My invention will be more readily understood by reference to the accompanying
drawing in which
Figure 1 is a sectional plan taken horizontally through the web of two adjacent
railway rails, showing a conductor embodying my invention attached to the same.
Figure 2 is a view of one of the connectors before its application to the rails,
and
Figure 3 shows one of the drift pins or plugs used to attach the connector to the
rail or conductor.
As shown in said drawing A A indicate the adjacent ends of two railway rails
which are connected by the usual fastening devices, such, for instance, as those
shown, and the webs of which are provided with holes a, a extending therethrough
in the manner shown. B indicates the rail bond which consists of a rod, bar or wire
having at its ends tubular or thimble-shaped terminals C C made of proper size for
insertion into the holes a, a and adapted to closely fit the said holes. The thimbles
or heads C C will be welded, forged or otherwise formed on the ends of the wire or
rod B. The connector B and its heads will preferably be made of copper, or other
suitable metal may be employed if desired. D D are drift pins or plugs which are
made somewhat larger in diameter than the openings or recesses of the tubular
heads or thimbles C C of the connector, and are adapted to be driven into the said
heads or thimbles after the same have been inserted in the holes a, a so as to
expand said heads or thimbles into contact with the walls of the holes. The drift
pins or plugs D will preferably be made somewhat conical on their advance ends so
that when driven into the heads or thimbles C they will expand every part of the
latter into solid contact with every part of the surface of the hole in the rail. The
said heads or thimbles C are shown as provided with slots or notches c at their
outer ends to facilitate the entrance of the drift pin or plug in inserting the same,
but these notches are not essential to the operation of the device,'
./

page_text: If desired the hole may be provided with a screw-thread, or a square-shaped or
other tool may be driven into it, or other process used to notch the surface of the
hole before the connector is inserted therein, so as to afford positive engagement of
the connector end with the hole and thus avoid possibility of its being loosened by
strain or vibration. Under ordinary circumstances, however, satisfactory results
are secured when the hole is left smooth, it being obvious that the driving of the
drift pin into the connector head or thimble, in the manner described, expands the
metal of which it is formed against the surface of the hole so as to exclude all air
and moisture and make the joint entirely proof against corrosion, oxidation or
electrolytic action.
I prefer to make the tubular end or thimble C of such diameter that the area of
the surface which is in contact with the main conductor will be equal at least to
seven times the cross sectional area of the wire or rod B, the result of this con-
struction being that the resistance to the passage of the electric current through the
joint will then be no greater than at any other part of the connector. I prefer to
thus construct the parts for the reason that the relative conductivity of copper and
iron is as seven to one, and in order to reduce the resistance to a minimum in the .
joint, where a copper conductor is connected with an iron one, the area of the copper
surface in contact with the iron should be at least seven times the cross sectional
area of the copper conductor.
It is not necessary that the drift pin or plug should be left within the tubular
head of the connector but it may be a hand tool used to expand the connector head
into the hole of the conductor and then removed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
A rail bond or connector for electric conductors composed of a rod, bar or wire
having tubular or thimble-shaped terminals and secured to electric conductors by
having said tubular or thimble-shaped terminals permanently expanded by stretching
or swaging of the metal composing them into contact with the holes in the
conductors, substantially as and for the purpose specified.
Dated this 16th day of January 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.