Improvements in or relating to Electric Railways on a Road Contact or like System.
Year: 1898

page_text: Complete Specification Left, 23rd June, 1899-Accepted, 29th July, 1899
Improvements in or relating to Electric Railways on a Road Contact
or like System.
:
I, LOUIS MINTURN ASPINWALL, of Pittsburg County of Allegheny, State of
Pennsylvania, United States of America, do hereby declare the nature of this
invention to be as follows:-
My invention relates to electric railways of the class in which current is
supplied to the car through a single series of exposed contact studs or rails,
provided in and insulated from the roadway, connection being made with said
contact studs or rails by means of a bar or shoe carried by the vehicle.
In systems of this kind an automatic switch is provided in the feeder wire which
connects each contact stud or rail with the supply main, said switches operating
to make the circuit when contact is made between a stud or rail and the shoe
carried by the car.
It has been proposed prior to my invention to employ a single line of roadway
contacts for performing the two functions of initially actuating the switches to
close the main circuit and for conducting the operating current to the vehicle-
propelling motor or motors; but, in order to make the switches reliable in
operation, this construction has usually been complicated to such an extent as to
materially increase the expense of installation beyond what is desirable, as, for
example, by providing either electromagnetic or mechanical means for inter-
rupting the circuit through the actuating electromagnet when the main circuit
is closed.
My invention consists in a special arrangement of the circuits through the
automatic switch whereby the necessity of interrupting the circuit through the
actuating electromagnet is avoided, and I do this by connecting one terminal
of the actuating coil with ground through a high resistance, the other terminal
of said coil being connected with the contact stud or rail in the roadway. The
resistance above mentioned is such as will permit sufficient current to pass to
effect the closing of the main circuit when no other path is provided for it,
but prevents the shunting through it of any large amount of current when the
supply main is connected.
My invention is illustrated in the accompanying drawings in which

page_text: Figure 1 is a diagram illustrating a section of roadway, a railway vehicle
and three forms of automatic switch having circuits arranged and otherwise
constructed in accordance with my invention.
Figures 2 and 3 are diagrams of modified forms of switches.
Figure 4 is a vertical section of one of the switches illustrated diagrammatically
in Figure 1.
Figure 5 is a plan view of the switch shewn in Figure 4 looking downward
and
Figure 6 is a corresponding view of the bottom looking upward.
Figure 7 is a detail sectional view of one of the movable shunt contacts.
Referring particularly to Figure 1, 1 and 2 are the track rails, and 3 are the
roadway contacts which are normally insulated from each other and from the
feeder 4. The roadway contacts are shewn in the form of rail sections, but the
operation of the system will be substantially the same if they are in the form
of more widely separated studs or plates. The only variation necessary in
the system for such construction would be in the form of the contact shoe. The
shoe 5, is in the present instance, shewn as made in two parts connected by a
suitable conductor, this arrangement being employed in order that a considerable
space may be bridged by the device. The motors 6 will be geared to the truck
wheels of the car and connected in circuit with suitable controlling apparatus,
as is usual and well understood in the art. 7 is a rotary transformer connected
at one side to a secondary battery 8 and at the other side to the shoe 5 and the
track rails, as is usual.
The arrangement is intended to be such that the comparatively small electro-
motive force of the storage battery will be raised by the rotary transformer
to approximately the working voltage of the system, so that substantially the
working voltage may be utilized in closing the switches.
I have shewn three forms of circuit making and breaking switch in Figure 1,
the switch a shewn at the left in said figure comprising a main contact piece 9ª
and an auxiliary contact piece 9b permanently connected to the feeder 4 and
corresponding contact pieces 9° and 9d permanently connected to ground through a
high resistance conductor 10 and to one terminal of a low resistance magnet
coil 11, the other terminal of said coil being permanently connected to one of the
roadway contacts 3. The coil 11 is enclosed in an iron casing 12 and is provided
with a movable core 13 which is connected to the movable member 14 of the
switch by means of a rod 15. The member 14 is provided with main and
auxiliary contact pieces, 14", 14, 14° and 14" that respectively co-operate with
the stationary pieces 9ª, 9, 9° and 9d, as is usual in this class of devices.
dashpot 16 may also be provided in order to prevent the switch from opening when
the current is reversed in the coil 11, but this will not be necessary, if the
core 13 is provided with a chamber that is suitable for properly co-operating
with the core to effect a similar function.
A
When the contact shoe 5 comes into engagement with the roadway contact 3
corresponding to switch a current from the rotary transformer 7 will pass through
coil 11 and the high resistance conductor 10 to ground, the resistance of the
latter being such that only a small quantity of current will pass through it. The
coil 11, thus energized, will close the switch and current will flow from the
feeder 4 through the parts 9", 14", 14, 14º, 9° and coil 11 to the motors, the high
resistance ground connection being thus shunted, and the switch held closed until
the shoe 5 breaks connection with the contact 3 which corresponds to said switch.
Each of the switches a¹ and a differs from the switch a in having the
operating coil 11 of high resistance through which current passes to ground
from either the rotary transformer 7 or the preceding roadway contact, and which
is short-circuited through low resistance coil 11, when the switch is closed.
The coil 11 is also connected in circuit between the feeder 4 and the motors,
when the switch is closed by means of contact pieces 17, but it is obvious that
very little, if any, current will pass therethrough..

page_text: It will be observed that the switches a¹ and a² are alike in construction but
differ as regards circuits in that the path to the ground in the former is around
coil 11, while in the latter, the patch is through such coil.
Switches a and a² are preferable to switch a in systems employing heavy
currents, since most of the large number of turns necessarily employed in con-
nection with the comparatively small secondary battery current for closing the
switch are short-circuited by the working current instead of being retained in
the main circuit as is the case in switch a.
Referring now to Figure 2, the magnet of switch a³ is provided with a coil 18
comprising a comparatively short low resistance portion 18 and a comparatively
long high resistance portion 18b, the feeder 4 being connected to the free
terminal of the portion 18 by a conductor 19, and the free terminal of the
portion 18 being connected to one stationary contact 20 of an initially acting
auxiliary switch a³, hereinafter designated as the initial switch. The iron
casing 12 has a middle partition 12" which is located between the coil 18 and
the actuating electro-magnet coil 11, and therefore insures approximately
independent magnetic circuits for these coils. The stationary contacts 9ª and 9b
of the main switch are connected to coil 18 between the sections 18" and 18b by
conductor 22, and the other stationary contacts 9° and 9d of the main switch are
connected to the corresponding roadway contact 3 by a conductor 23. The
terminals of the coil 11 are connected respectively to the conductor 23 and to the
ground through the high resistance conductor 10. This coil is also connected
to the stationary contact 20% of the initial switch. The movable contacts 14",
14ª, 14ª and 14 of the main switch are connected by a bridge 14, and this is
connected, by means of a rod 24 to a core 25 located above the partition 12" and
within the magnetic field of the coil 18. The movable contacts 26 and 26* are
also connected by a bridge 27 and the latter is supported by the core 28 for the
coil 21.
A coiled spring 29 is preferably interposed between the two members 14
and 27.
The contacts 9b and 9ª, 14, 14ª, 20, 20, 26 and 26 are preferably formed of
carbon or of some other substantially infusible material, while the other switch
contacts are made of metal in order to provide a path of low resistance for the
main current, the final break being made by the small supplemental carbon
contacts 9b, 9, 14b and 14d.
The switch a, shewn in Figure 3, differs from switch only in having a
single low resistance coil 18 in the upper portion of the magnet.
The operation of the system, where switches like switch a³ are employed, is
as follows: Assuming that all the switches are open and the shoe 5 comes
into engagement with the roadway contact corresponding to a given switch, the
current from the stationary battery 7 will pass through the shoe 5, the roadway
contact 3 with which it is in engagement, the conductor 23, coil 11, and resist-
ance 10, to the ground. This current will energize the coil 11 sufficiently to
raise the number 27 of the initial switch, thus closing the circuit from the
feeler 4 through the sections 18° and 18b of the coil 18, the contacts 20, 26,
26, 20, the coil 11 and conductor 23 to the roadway contact 3; through
the shoc 5, the controlling devices (not shewn), and the motors to the track
rails and ground. This current will energize the coil 18 sufficiently to effect
the closing of the main switch, and when this is effected both the coil 21 and
the coil section 18b will be short-circuited, thus leaving but very small resistance
in the main circuit, the coil section 18 being of comparatively large wire and
few turns. In this form of switch, all of the turns in coil 18 are utilized for
closing the main switch while only the short length 18 of low resistance wire is
included in the main circuit during the time that the main switch is closed.
The operation of the switch a is substantially the same as that already
described, except that the entire coil 18 is retained in the main circuit during
the time that the main switch is closed. As the direction of current flowing

page_text: through the coil 11 is reversed when the switch is closed, the core should be so
combined with the stationary part of the magnet as to have a dashpot effect to
prevent the opening of the switch at the reversal of the magnetism, or a separate
dashpot provided, as is indicated in connection with switch a. Inasmuch as it is
'feasible to so construct the cores as to effect this result, it has not been deemed
necessary to illustrate a separate dashpot in connection with each switch. The
spring 29 between the movable switch members obviously tends to ensure inde-
pendent operation of such members.
If, from any cause, the working current should not be heavy enough to either
close or maintain closed the main switch shewn in Figure 2 or that shewn in
Figure 3, the initial switch a will serve to carry such current until its volume
is sufficient to effect the closing of the main switch.
The construction of the switch illustrated in Figures 4 to 7 has been already
sufficiently described except as regards the carbon shunt contacts, one of which
is shown in detail in Figure 7.
It will be seen by reference to this figure that each of these contacts rests upon
a spiral spring 30 which tends to force it upward, so that when the movable
member of the switch drops by the action of gravity, the shunt contacts will
be held in engagement after the main metal contacts are separated, thus guarding
against any possible injury to the metal contacts' by the interruption of the
circuit.
I desire it to be understood that the auxiliary shunt contacts 9b, 9, 14 and 14
are not essential to my invention, since the main contacts may be formed of
carbon and the auxiliary contacts omitted, if desired. One pair of contacts 17,
instead of two, may also be employed in switch a¹.
It will be understood also that when the first switch of the system has been
closed by the action of the current from the rotary transformer 7, the subsequent
switches may be closed by the action of current from the feeder 4, inasmuch as
the shoe 5 is of sufficient length to bridge over the roadway contact in advance
of that which is immediately under the car and supplying current to the motors.
Dated this 24th day of September 1898.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C.,
Patent Agents for the Applicant.
.
FINAL SPECIFICATION.
Improvements in or relating to Electric Railways on a Road Contact
or like System.
I, LOUIS MIXTURN ASPINWALL, of Pittsburgh, in the County of Allegheny, and
State of Pennsylvania, United States of America, Electrical Engineer, do hereby
. declare the nature of this invention and in what manner the sanie is to be
performed, to be particularly described and ascertained in and by the following
:statement:
My invention relates to electric railways of the class in which current is
.supplied to the car through a single series of exposed contact. studs or rails,
provided in and insulated from the roadway, connection. being made with said
contact studs or rails by means of a bar or shoe carried by the vehicle.
In systems of this kind an automatic switch is provided in the feeder wire which

page_text: connects each contact stud or rail with the supply main, said switches operating
to make the circuit when contact is made between a stud or rail and the shoe
carried by the car.
The
My invention consists in a special arrangement of the circuits through the
automatic switch whereby the necessity of interrupting the circuit through the
actuating electromagnet is avoided, and I do this by connecting one terminal
of the actuating coil with ground through a high resistance, the other terminal
of said coil being connected with the contact. stud or rail in the roadway.
resistance above mentioned is such as will permit sufficient current to pass to
effect the closing of the main circuit when no other path is provided for it,
but prevents the shunting through it of any. large amount of current when the
supply main is connected.
My invention is illustrated in the drawing left with my Provisional Specifica-
tion in which,
Figure 1 is a diagram illustrating a section of roadway, a railway vehicle
and three forms of automatic switch having circuits arranged and otherwise
constructed in accordance with my invention.
Figures 2 and 3 are diagrams of modified forms of switches.
Figure 4 is a vertical section of one of the switches illustrated diagrammatically
in Figure 1.
Figure 5 is a plan view of the switch shewn in Figure 4 looking downward
ánd
Figure 6 is a corresponding view of the bottom looking upward.
Figure 7 is a detail sectional view of one of the movable shunt contacts.
Referring particularly to Figure 1, 1 and 2 are the track rails, and 3 are the
roadway contacts which are normally insulated from each other and from the
feeder 4. The roadway contacts are shewn in the form of rail sections, but the
operation of the system will be substantially the same if they are in the form
of more widely separated stud or plates. The only variation necessary in
the system for such construction would be in the form of the contact shoe. The
shoe 5, is in the present instance, shewn as made in two parts connected by a
suitable conductor, this arrangement being employed in order that a considerable
space may be bridged by the device. The motors 6 will be geared to the truck
wheels of the car and connected, in circuit with suitable controlling apparatus,
as is usual and well understood in the art. 7 is a rotary transformer or motor
dynamo connected at one side to a secondary battery 8 and at the other side to the
shoe 5 and the track rails, as is usual.
The arrangement is intended to be such that the comparatively small electro-
motive force of the storage battery will be raised by the motor dynamo
to approximately the working voltage of the system, so that substantially the
working voltage may be utilized in closing the switches.
- 'I have shewn three forms of circuit making and breaking switch in Figure 1,
the switch a shewn at the left in said figure comprising a main contact piece 9*
and an auxiliary contact piece 9b permanently connected to the feeder 4 and
corresponding contact pieces 9° and 9d permanently connected to ground through a
high resistance conductor 10 and to one terminal of a low resistance magnet
coil 11, the other terminal of said coil being permanently connected to one of the
roadway contacts 3. The coil 11 is enclosed in an iron casing 12 and is provided
with a movable core 13 which is connected to the movable member 14 of the
switch by means of a rod 15. The member 14 is provided with main and
auxiliary contact pieces, 14, 14, 14° and 14d that respectively co-operate with
the stationary pieces 9, 9b, 9° and 9d, as is usual in this class of devices. Á
dashpot 16 may also be provided in order to prevent the switch from opening when
the current is reversed in the coil 11, or the core 13 may be provided with a
chamber that is suitable for properly co-operating with the core to effect a similar
function.
When the contact shoe 5 comes into engagement with the roadway contact 3

page_text: corresponding to switch a current from the rotary transformer will pass through
coil 1 and the high resistance conductor 10 to ground, the resistance of the.
latter being such that only a small quantity of current will pass through it. The
coil 11, thus energised, will close the switch and current will flow from the
feeder 4 through the parts 9", 14, 14, 14°, 9° and coil 11 to the motors, the switch
being held closed until the shoe 5 breaks connection with the contact 3 which
corresponds to said switch.
Each of the switches a¹ and a differs from the switch a in having the
operating coil 11 of high resistance through which current passes to ground
from either the rotary transformer 7 or the preceding roadway contact. The
coil 11 is also connected in circuit between the feeder 4 and the motors, when
the switch is closed by means of contact pieces 17, but it is obvious that very little,
if any, current will pass therethrough.
It will be observed that the switches a¹ and a² are alike in construction but
differ as regards circuits in that the path to the ground in the former is around
coil 11, while in the latter, the path is through such coil.
Switches a¹ and a³ are preferable to switch a in systems employing heavy
currents, since most of the large number of turns necessarily employed in con-
nection with the comparatively small rotary transformer current for closing the
switch are not traversed by the working current as is the case in switch a.
Referring now to Figure 2, the magnet of switch a³ is provided with a coil 18
comprising a comparatively short low resistance portion 18 and a comparatively
long high resistance portion 18b, the feeder 4 being connected to the free
terminal of the portion 18 by a conductor 19, and the free terminal of the
portion 18 being connected to one stationary contact 20 of an initially acting
The iron
auxiliary switch a³, hereinafter designated as the initial switch.
casing 12 has a middle partition 12 which is located between the coil 18 and
the actuating electro-magnet coil 11, and therefore insures approximately
independent magnetic circuits for these coils. The stationary contacts 9" and 9b
of the main switch are connected to coil 18 between the section 18" and 18b by
conductor 22, and the other stationary contacts 9° and 9d of the main switch are
connected to the corresponding roadway contact 3 by a conductor 23.
terminals of the coil 11 are connected respectively to the conductor 23 and to the
ground through the high resistance conductor 10. This coil is also connected
to the stationary contact 20" of the initial switch. The movable contacts 14"
14b, 14 and 14d of the main switch are connected by a bridge 14, and this is
connected, by means of a rod 24 to a core 25 located above the partition 12" and
within the magnetic field of the coil 18. The movable contacts 26 and 26" are
also connected by a bridge 27 and the latter is supported by the core 28 for the
coil 11.
The
A coiled spring 29 is preferably interposed between the two members 14
and 27.
The contacts 9b and 9, 14, 14ª, 20, 20, 26 and 26° are preferably formed of
carbon or of some other substantially infusible material, while the other switch
contacts are made of metal in order to provide a path of low resistance for the
main current, the final break being made by the small supplemental carbon
contacts 9b, 9, 14 and 14d.
The switch a', shewn in Figure 3, differs from switch a³ only in having a
single low resistance coil 18 in the upper portion of the magnet.
The operation of the system, where switches like switch are employed, is
as follows: Assuming that all the switches are open and the shoe 5 comes
into engagement with the roadway contact corresponding to a given switch, the
current from the transformer 7 will pass through the shoe 5, the roadway
contact 3 with which it is in engagement, the conductor 23, coil 11 and resist-
ance 10, to the ground. This current will energize the coil 11 sufficiently to
raise the number 27 of the initial switch, thus closing the circuit from the
feeder 4 through the sections 18" and 18" of the coil 18, the contacts 20, 26,

page_text: 26, 20, the coil 11 and conductor 23 to the roadway contact 3; through
the shoe 5, the controlling devices (not shewn), and the motors to the track
rails and ground. This current will energize the coil 18 sufficiently to effect
the closing of the main switch, and when this is effected both the coil 11 and
the coil section 18b will be short-circuited, thus leaving but very small resistance
in the main circuit, the coil section 18" being of comparatively large wire and
few turns. In this form of switch, all of the turns in coil 18 are utilized for
closing the main switch while only the short length 18" of low resistance wire is
included in the main circuit during the time that the main switch is closed.
The operation of the switch at is substantially the same as that already
described, except that the entire coil 18 is retained in the main circuit during
the time that the main switch is closed. As the direction of current flowing
through the coil 11 is reversed when the switch is closed, the core should be so
combined with the stationary part of the magnet as to have a dashpot effect to
prevent the opening of the switch at the reversal of the magnetism, or a separate
dashpot provided, as is indicated in connection with switch a. Inasmuch as it is
feasible to so construct the cores as to effect this result, it has not been deemed
necessary to illustrate a separate dashpot in connection with each switch. The
spring 29 between the movable switch members obviously tends to ensure inde-
pendent operation of such members.
If, from any cause, the working current should not be heavy enough to either
close or maintain closed the main switch shewn in Figure 2 or that shewn in
Figure 3, the initial switch a will serve to carry such current until its volume
is sufficient to effect the closing of the main switch.
The construction of the switch illustrated in Figures 4 to 7 has been already
sufficiently described except as regards the carbon shunt contacts, one of which
is shewn in detail in Figure 7.
It will be seen by reference to this figure that each of these contacts rests upon
a spiral spring 30 which tends to force it upward, so that when the movable
member of the switch drops by the action of gravity, the shunt contacts will
be held in engagement after the main metal contacts are separated, thus guarding
against any possible injury to the metal contacts by the interruption of the
circuit.
I desire it to be understood that the auxiliary shunt contacts 9b, 90, 14b and 14d
are not essential to my invention, since the main contacts may be formed of
carbon and the auxiliary contacts omitted, if desired. One pair of contacts 17,
instead of two, may also be employed in switch a¹.
It will be understood also that when the first switch of the system has been
closed by the action of the current from the rotary transformer 7, the subsequent
switches may be closed by the action of current from the feeder 4, inasmuch as
the shoe 5 is of sufficient length to bridge over the roadway contact in advance
of that which is immediately under the car and supplying current to the motors.
I wish it understood that the drawings herein referred to are mere diagrams
and are not to be taken as correct views of practicable mechanical forms of
apparatus.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In an electric railway of the class described an automatic switch having an
actuating magnet coil one terminal of which is permanently connected to earth
for the purpose specified..
2. The modification of the invention in which the actuating magnet coil of
the automatic switch one terminal of which is connected to earth is short-
circuited by a second magnetic coil in the feeder wire when the switch is
closed.
3. In an electric railway of the class described an automatic switching device

page_text: elies
having two electro-magnetically operated switches the closing of the first of said
switches ensuring the operation of the second the closing of which short-circuits
the actuating coil of the first switch, for the purpose specified.
14. The various automatic switching devices either with or
auxiliary contacts constructed and operating substantially as described.
Dated the 23rd day of June 1899.
without the
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham.