Improvements in Contact Apparatus for Receiving Currents from Overhead Conductors on Electric Railways.
Year: 1893

page_text: Date of Application, 14th Sept. 1893
Complete Specification Left, 4th June, 1894-Accepted, 7th July, 1894
PROVISIONAL SPECIFICATION.
Communicated from abroad by Messrs. SIEMENS & HALSKE, of Berlin, in the
German Empire, Electrical Engineers.]
Improvements in Contact Apparatus for Receiving Currents from
Overhead Conductors on Electric Railways.
We, SIEMENS BROTHERS & Co. LIMITED, of 12 Queen Anne's Gate,
Westminster, in the County of Middlesex, Electrical Engineers, do hereby declare
the nature of this invention to be as follows:-
In electric railways in which the current conductors are situated above ground,
the rails of the line are generally used as the return conductor, so that the current-
receiving device on the electro motor vehicle only requires to be arranged for
If however the rails cannot
taking off the current from a single raised conductor.
be used as the return conductor, then two or more overhead conductors must be
provided for conveying both the supply and the return current for the electro
motor, and two contact devices must be provided for respectively receiving and
giving off the current.
This has also to be effected in the case of electro motors that are worked by
three-phase alternating currents, as, if the rails be used for one of the currents,
there must still be two overhead conductors for the other two currents. If the two
contact devices for taking off the currents from these were simply connected in an
insulated manner to a single current receiver, then the continuous simultaneous
contact between both the contact pieces and the conductors could not be insured
on account of the varying relative positions of the latter, and as a consequence the
action of the electro motor would either be interrupted or become defective.
This invention relates to an improved current receiver which obviates this
difficulty in a very simple manner; it consists in arranging two contact devices on
the current receiver in such manner that they can each make contact with a
conductor independently of the other one, even with the greatest possible variations
in the relative positions of the conductors.
For this purpose an arm projecting up in an inclined position from the electro
motive vehicle has pivotted to its upper end a head piece consisting of two
horizontally projecting bars which are of conducting material and are insulated
from each other, and which extend transversely across the two overhead conductors,
on the underside thereof, the inclined arm being pivotted at its lower end and
acted upon by a spring so as to press the said conducting bars of the head which
constitute the contact devices against the undersides of the conductors.
Thus when the conductors sag down, the one lower than the other, the head in
turning on its pivot will allow the conducting limbs to assume correspondingly
inclined positions so as to maintain them both in effective contact with the
conductors. A wire leads from each insulated contact device down the arm to the
electro motor. At the inner end of each contact bar is a rotatable star-shaped
disc which both prevents the conductors from passing from the one contact bar
over to the other, when passing round curves &c., and also helps the bar to pass
the points where the conductors are connected to suspending wires, without
breaking the contact.
The contact bars may either slide directly in contact with the conductors, or

page_text: they may carry flanged or grooved rollers of conducting material in the groove of
which the conductor lies, the rollers being free to revolve upon and to slide along
the contact bars.
The flanges of these rollers may be made star shape for the purpose of
facilitating the passage of the contact bars past the suspending devices of the
conductors, as before mentioned.
This arrangement may also be rendered applicable to cases where the conductors
of two different lines of railway cross each other, the crossing parts of the two
conductors being covered with insulating material for a certain length. In this
case the roller is made sufficiently wide between its flanges to pass such crossing
of the conductors and it has attached to opposite sides thereof spring arms
terminating in flat contact pieces that slide along the underside of the conductor.
These contact pieces are at a greater distance apart than the length of the
insulated part of the conductor at the crossing, so that when passing such crossing
one or other of the contact pieces will always be in contact with a non-insulated
part of the conductor, and thus the transmission of the current will never be
interrupted.
Dated this 14th day of September 1893.
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Contact Apparatus for Receiving Currents from
Overhead Conductors on Electric Railways.
We, SIEMENS BROTHERS & Co. LIMITED, of 12 Queen Anne's Gate,
Westminster, in the County of Middlesex, Electrical Engineers, 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 :-
In electric railways in which the current conductors are situated above ground,
the rails of the line are generally used as the return conductor, so that the current-
receiving device on the electro-motor vehicle only requires to be arranged for
taking off the current from a single raised conductor. If however the rails cannot
be used as the return conductor, then two or more overhead conductors must be
provided for conveying both the supply and the return current for the electromotor,
and two contact devices must be provided for respectively receiving and giving off
the current.
This has also to be effected in the case of electro motors that are worked by
three-phase alternating currents, as, if the rails be used for one of the currents,
there must still be two overhead conductors for the other two currents. If the two
contact devices for taking off the currents from these were simply connected in an
insulated manner to a single current receiver, then the continuous simultaneous
contact between both the contact pieces and the conductors could not be insured on
account of the varying relative positions of the latter, and as a consequence the
action of the electromotor would either be interrupted or become defective.
This invention relates to an improved current receiver which obviates this
difficulty in a very simple manner; it consists in arranging two contact devices on
the current receiver in such manner that they can each make contact with a
conductor independently of the other one, even with the greatest possible variations
in the relative positions of the conductors.
For this purpose an arm projecting up in an inclined position from the electro
motive vehicle has pivotted to its upper end a head piece consisting of two
horizontally projecting bars which are of conducting material and are insulated
from each other, and which extend transversely across the two overhead conductors,

page_text: on the underside thereof, the inclined arm being pivotted at its lower end and
acted upon by a spring so as to press the said conducting bars of the head which
constitute the contact devices against the undersides of the conductors.
Thus when the conductors sag down, the one lower than the other, the head in
turning on its pivot will allow the conducting limbs to assume correspondingly
inclined positions so as to maintain them both in effective contact with the
conductors.
Fig. 1 of the accompanying drawing shews one arrangement of a current
receiver constructed according to this invention.
The arm T, which is pivotted at its lower end and held in an inclined position by
a spring as shewn in the part side view at Fig. 14, has attached to its upper end
by a pivot at A, a head piece E provided on each side with a horizontal bar Qof
conducting material, these bars being insulated from each other by insulating
blocks E. Each of the bars Q is connected by a separate wire D with the
electromotor on the vehicle.
The spring arm T keeps the conducting bars Q against the underside of the two
suspended conducting wires 11, so as to make electrical contact therewith, and it
will be seen that when these wires are at different levels owing to the span of the
one sagging down lower than that of the other, an effective contact will still be
maintained between each bar Q and its conducting wire by the head E turning on
its pivot at A so as to cause the bars to assume a corresponding inclined position.
In order to prevent the conducting wire from passing off from its bar Q on to
the other one, for example on curves, there is provided at the inner end of each bar
a rotatable cross or star shaped guard R, which will retain the conductor l, should
this be brought against it. The guard requires to be of a cross or star shape, as
otherwise the current receiver would not be able to pass those points where the
conductors are attached to transverse supporting wires without putting the arms Q
out of contact with the conductors.
In the arrangement shewn at Fig. 2 the contact devices of the pivotted head E do
not consist merely of two bars, which slide along the conductors, but of bars on
which are mounted rollers R also of conducting material, that are free both to
rotate and to slide longitudinally upon the bars, the conducting wires 1 being
retained on these rollers by lateral flanges, so that according as the position of the
wires may vary upon the bars, the rollers will always shift to a corresponding
extent and the contact will be a rolling instead of a sliding one.
The modification shewn at Fig. 3 only differs from the foregoing one in that the
sides of the rollers Rare provided with cross or star shaped guards, for the purpose
above referred to.
The arrangement shewn in perspective at Fig. 4, serves to indicate that the
invention is equally applicable to conducting wires that cross each other or are
branched at certain points.
At those points for example where wires conducting currents of different potential
cross each other, the crossing parts being suitably insulated from each other, the
arrangements described with reference to Figs. 1 to 3 would either effect a short
circuiting between the crossing wires, as indicated at the right hand side of Fig. 4,
or the circuit of the electromotor would be broken by the insulated portion of the
crossing wires.
To avoid this, there is mounted upon the bars Q a sliding roller or sleeve C
Fig. 4 carrying two opposite spring arms with sliding contacts I bearing against
the conducting wires these contacts being in conducting connection with each
other and with the bar Q, and situated at such a distance from each other, that
at the insulated crossings at least one of the contact pieces I will always be in
conducting contact with the wire l. On each side of the roller or sleeve C are
provided rotatable cross shaped guards H, as before.
It will be evident that various other devices may be employed for establishing
the conducting contact between the pivotted conducting bars Q and the circuit
wires l.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In contact apparatus for receiving currents from overhead conductors,
-constructing a current receiving arm having spring action with a pivotted head
from either side of which projects a contact device for making conducting
contact with one of two overhead conductors, so that when such conductors are
at different levels the head will assume a corresponding inclined position in
turning on its pivot, and thus maintain each contact device in proper contact with
its conductor, substantially as described.
2. In contact apparatus such as is referred to in the preceding claim, the several
constructions of the pivotted head with contact devices herein described with
reference to the accompanying drawings.
Dated this 4th day of June 1894
ABEL & IMRAY,
Agents for the Applicants.