Improvements in and relating to Electric Motors.
Year: 1893

page_text: Date of Application, 12th Dec., 1893-Accepted, 5th May, 1894
Improvements in and relating to Electric Motors.
I, WILLIAM PHILLIPS HALL, of Greenwich, in the County of Fairfield, and
State of Connecticut, United States of America, President of Railway Signal
Company 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 is generally applicable to all devices to be moved, but is especially
designed for railway signal arms or semaphores, railway gates, railway switches, etc.,
in which the arms, semaphores gates, switches, etc., are t receive a definite
movement upon the breaking or closing of a circuit or upon the happening of some
event such as the approach or recedence of a train. It consists of means for
utilizing an ordinary rotary electro-motor to cause these movements. The means
embodying my broad invention consists of a centrifugally operated clutch inter-
posed between the electro-motor and the device to be moved so that at low speeds,
the motor not connected to the device to be moved, but as the speed of the
motor increases the centrifugal clutch acts to hold the revolving parts together
and the power is applied to move the device. The employment of this centrifugal
clutch permits the electro-motor to acquire a high speed and to store up consider-
able momentum before any work is put upon it. It also permits the work to be
applied gradually to the electro-motor, as the centrifugal clutch may be so
constructed that as the electro-motor approaches the speed at which the clutch will
positively grip and hold the parts of the clutch together, the parts will slip to
some extent, but nevertheless the movement of one will cause a slight movement of
the other and this slip will gradually decrease until the gripping speed is reached.
My entire invention includes a gearing connected at its fast end by the centrifugal
clutch to the electro-motor, and connected at its slow end to the device to be
moved, and a switch connected to the moving mechanism for cutting off the
current from the electro-motor and applying an electrically-operated brake at the
completion of a definite movement of the device to be moved, and for continuing
Also a
the application of the brake until the cessation of the electrical current.
relay for controlling the movement of the device by making and breaking the
actuating circuit.
For the purpose of fully explaining my invention I have shown in Figures 1, 2
and 3 of the drawings, an application of the same to operate the semaphore arm of
a railway signal, and in Figures 4 and 5, another application of the same for
operating a railway switch.
Figure 1 is a front elevation of the signal post, semaphore arm and operating
mechanism;
Figure 1 is an enlarged detail of a portion of the centrifugal clutch.
Figure 2 is a side elevation showing the operating mechanism, with the enclosing
case in section.
Figure 3 is an enlarged horizontal section of the centrifugal clutch taken on
the line 3-3, Fig. 1;
Figure 4 is a sectional elevation of the electro-motor, railway switch and
connecting mechanism, and Figure 5 is a plan view of the same.
The electro-motor c is shown in Figs. 1, 2, 4 and 5. Its shaft c³ has secured
to it a collar d provided with radial bearings in which are fitted to slide the
gripping pieces e. The outer peripheries of these gripping pieces fit against the
inner periphery of a wheel or flanged disc f, fitted so as to rotate independently of

page_text: the shaft c¹ and connected with the device to be moved. This disc will not by
its rotation cause any movement of the motor shaft c¹, while, on the other hand,
the rotation of the motor shaft, when at a sufficiently high speed to cause the
gripping pieces or grippers e to tightly grip the inner periphery of the disc f, will
cause the rotation of the disc fand devices connected therewith. To regulate the
gripping action of the grippers e, springs e¹ are provided which tend to pull the
grippers toward the centre, thus resisting the centrifugal action. These springs
and the weight of the grippers can be so adjusted that this clutch will hold the
motor shaft c and disc f so as to rotate together at any desired speed. It will be
noted also that the clutch may be constructed so that the engagement of the two
rotating parts will occur very gradually as the motor shaft approaches its gripping
speed, by making the engaging faces of the clutch smooth and non-adherent, so
that there will be considerable slip before the positive engagement of the faces
take place. This arrangement will permit the motor to acquire a high rotative
velocity and to store up considerable momentum before the work is put upon it.
I have shown in the drawings two arrangements of mechanism for connecting
the disc of the centrifugal clutch with the devices to be moved.
I will first
describe that shown in Figs. 1, 2 and 3, which embodies my entire invention. In
this construction the motor and clutch are connected with a semaphore arm a,
supported by the post b. Only a portion of the arm. a and post are shown in
the drawings. The electro-motor is mounted within a protecting casing at the
side of the post, and is connected through a train of gearing and connecting rod
to the semaphore arm. The disc is secured to or upon a sleeve fitted loosely
upon the electro-motor shaft c', and a pinion is formed upon or secured to this
sleeve. The pinion 9 meshes with the gear wheel h mounted upon the same shaft
with the pinion; the pinion i meshes into the gear wheel i mounted on the same
shaft as the pinion k; the pinion k meshes into the toothed sector 1, mounted on
the same shaft as the arm 1, and the arm is joined by the connecting rod to
the semaphore arm a.
g
The semaphore arm is shown in its horizontal or danger position. It is advisable
to make this danger position the normal position of the semaphore arm, and to
that end the semaphore is shown counter-weighted at a' on the opposite side of
the centre from the arm, the weight a¹ being sufficient to hold the semaphore arm
at the danger position under all ordinary circumstances. The power of the
electro-motor is applied for the purpose of pulling down the arm from the
horizontal danger position to the nearly vertical or safety position.
When the semaphore has reached the safety position, no further movement of
the mechanism in that direction is required. therefore provide a switch for
cutting off the supply of electric current to the motor, and an electrically-operated
brake to be applied to the moving mechanism at about the end of the downward
movement of the semaphore. The switch m is shown mounted in the upper
part of the casing and connected by the actuating rod m', bell-crank m and
connecting rod m³ with an arm mounted on the same shaft as the sector l. The
switch could, of course, be connected with any suitable. moving part of the
mechanism. The switch m is shown as a snap switch, the object of this con-
struction being to make the switch arm n move quickly from the contact plate n'
to the contact plate n'. The switch arm n is connected by the wire to, the
battery B. The contact plate n' is connected by the wire 2 and through the coils
of the electro-motor c and wire 4 to the other end of the battery B. The contact
plate is connected by the wire 5 and through the coils of the electro-magnet o
and wire 6 to the wire 4, thence of course to the same end of the battery Bas
the contact plate n When therefore the switch-arm n is in contact with the
plate, n', the current from battery B flows through the electro-motor coils and is
cut off from the electro-magnet o, and when the switch arm n is in contact with
the plate n the current is cut off from the electro-motor coils and flows through.
the electro-magnet o. This electro-magnet o has an armature connected with the
brake-shoe o arranged to bear upon the outer periphery of the disc f. The
.

page_text: urrent flowing through this electro-magnet causes the brake o' to be appreu to
he disc fand speedily checks the movement of the mechanism.
A relay is shown for controlling the semaphore, although of course it is obvious
hat any suitable circuit breaker may be used. This relay R has an armaturer,
The relay R
which when attracted by the relay magnet closes a break in wire 4.
may be operated by track circuits or track instruments or other automatic or
and-operated devices, at any desired distance from the semaphore.
In the positions of parts shown in the drawings the relay circuit R has just been
The electro-
losed and the electro-motor is about to commence its movement.
notor will revolve freely until it has attained the speed at which it is to be
connected with the semaphore, and then it will gradually or quickly, as may be
lesired, through its centrifugal clutch, impart motion to the semaphore operating
mechanism and pull the semaphore downward toward the safety position. If the
weight of this mechanism proves at any time too much for the electro-motor, so as
to cause a diminution of its speed, the electro-motor would be temporarily
When the semaphore has
disconnected and would store up more momentum.
about reached its safety. position the arm. of the switch m is suapped over and
contact is broken between the switch arm n. and plate n', and made between the
switch arm n and plate n². Thereby the current is cut off from the electro-motor
and sent through the brake-actuating magnet o, and the brake o¹ is applied to the
mechanism. It will be noted here that as soon as the speed of the mechanism
becomes lower than the gripping speed of the centrifugal clutch, the electro-motor
will be disconnected and will slowly and freely come to rest, so that all sudden
shocks to the electro-motor are prevented. The brake o¹ will be held in contact
with the disc funtil the circuit of the electro-magnet o is broken, and this circuit
will not ordinarily be broken until the relay R releases its armature r.
however, the semaphore were moved by hand, or otherwise, from its safety position
while the circuit of battery B remains closed at the point r, the current will be
switched through the electro-motor and the semaphore will be immediately
returned to safety position. Thus it will be seen that the mechanism acts to move
the semaphore to the safety position and to hold it in that position so long as the
current of its actuating battery is closed. As soon, however, as the current of
the battery B is broken at the point r, the mechanism is released and the
semaphore returns to the danger position. It will be noted that this return
movement of the semaphore mechanism and of the disc does not cause rotation of
the armature, and thus the electro-magnet is guarded against any unnecessary
movements. The disc f and connected gearing act to regulate the return movement
of the semaphore by reason of the resistance of the air to their rapid rotation, and
thus prevent a too rapid return movement and prevent a sudden jar or shock of the
semaphore at the completion of such return movement when the semaphore reaches
the danger position and comes against its stop.
If,
The
In Figures 4 and 5 the connecting gearing between the centrifugal clutch and
the device to be moved (in this case a switch) consists of a revolving screw and its
nut and suitable arms and links. The sleeve d is rigidly fixed to the shaft c.
disc fis rigidly mounted upon a separate shaft p, in alignment with shaft c, which
rotates in suitable bearings and is screw threaded between its bearings. A nut q
meshes into the threaded portion of the shaft p and is guided by the straight guide
arms qq, which engage with projections from the nut, so that it slides in a
straight line when the screw shaft
Links ss are also connected to the
is rotated.
nutq and to the switch lever t. The switch lever t is pivotally mounted and has
vvare the moving
secured to it the link t¹, connecting it with the switch bar u.
tongues of the switch and w 10 the rails.
With this construction it is necessary to actuate the electro-motor for each
movement of the switch. It will therefore be necessary to send the current in one
direction through the motor to move the switch in one direction, and to reverse the
current for a reverse movement of the switch. This is provided for by the
arrangement of switches shown diagrammatically in Fig. 4. The switch lever y is

page_text: controlled by a sliding bar y', and this sliding bar y¹ has two projections y³ and y',
which engage with the projection q³ of the sliding nut q. There are two contacts
to this switch, one connected to the wire 7 and the other to the wire 9. When the
nut is in the extreme right hand position, as shown in Fig. 4, the switch lever y is
in contact with the wire 7. When the nut q is in the extreme left hand position,
the switch lever y is in contact with the wire 9. While the nut is moving in the
intermediate positions the switch lever is unaffected. For instance, the nut gas
shown in Fig. 4, is about to move to the left and will not operate the switch until
just before it reaches the extreme left hand position.
The apparatus may be operated and controlled by a relay or by a hand-operated
switch. The drawings show a hand-operated switch containing a handle and two
mechanically connected but electrically insulated switch bars x1 and 3. The
switch bar is connected with one pole of the battery B', and the switch bar is
connected with the other pole of said battery. There are three contacts.
One of
these contacts is connected directly by the wire 7 to a corresponding contact in the
switch on the machine. The second of these contacts is connected by the wire 8,
through the coils of the electro-motor, to the switch lever y on the machine. The
third contact is connected by the wire 9 directly to the second contact of the
switch on the machine. As shown, the switch bars r¹ and have just been
operated to connect the wires 7 and 8 to the battery B¹, and the current flows
through the switch bar by the wire 8, including the coils of the electro-magnet,
and from the wire 8 through the switch lever y to the wire 7, and through switch
bar back to the battery. The electric current will now flow through the
electro-motor and cause the mechanism to close the railway switch. At the
completion of the closing of the railway switch, the lever y breaks contact with
the wire 7, thus breaking the electro-motor circuit. To cushion the stroke of the
switch lever and prevent jarring, I provide a spring, against which the lever t
will come in contact at about this part of its movement. The railway switch will
remain closed until the switch bars and are operated to bring ¹ into contact
with the wire 8 and into contact with the wire 9; then the current will flow
from the battery through bar and the wire 9, switch bar y, (which is now in
contact with wire 9) wire 8 and electro-motor coils, and back to the battery by the
switch bar, thus flowing in the reverse direction from that in which it flowed to
close the switch. This will cause the electro-motor and connected parts to move
in the opposite direction from that employed in closing the railway switch, and will
therefore result in opening the switch. Just before the nut y returns to its extreme
right hand position, it will move the switch lever y so as to break contact with the
wire 9 and thus cut off the supply of current from the electro-motor. The spring 2¹,
working against the lever t, will cushion the shock of the mechanism as it comes to
a standstill.
This construction makes it possible to control the switch at any desired distance
therefrom, either manually or automatically. The current is permitted to flow
until the work has been accomplished and the circuit is broken, but at the same
time the parts are put in position to be operated in the reverse direction upon a
change in the operating switch or relay. It is obvious that other applications may
be made of my broad invention, and various modifications may be made in the
applications shown without departing from the spirit of my broad invention.
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. The combination of an electric motor and a circuit therefor, a device to be
moved by the motor, a brake and a circuit therefor, said circuits so operatively
connected with the moving parts that when they have completed a definite
movement the circuit for the motor is automatically deenergized and the circuit
for the brake is automatically energized, substantially as set forth.
2. The combination of an electric motor and a circuit therefor, a device to be

page_text: moved by the motor, a brake and a circuit therefor, a switch for said circuits
automatically operated by the moving parts to deënergize the circuit for the motor
and energize the circuit for the brake, substantially as set forth.
3. The combination of an electric motor and a circuit therefor, a device to be
moved by the motor, a brake and a circuit therefor, said circuits so operatively
connected with the moving parts that when they have completed a definite
movement the circuit for the brake is automatically energized, substantially as set.
forth.
4. The combination of an electric motor and a circuit therefor, a device to be:
moved by the motor, a brake and a circuit therefor, a switch for said circuits
automatically operated by the moving parts to energize the circuit for the brake,,
substantially as set forth.
5. The combination with an electro-motor and a device to be moved thereby,.
and a circuit for conveying current to the electro-motor, of an electrically-actuated
brake controlling, when operated, the movement of said device, and a circuit for
said brake, and a switch operated by the moving parts to cut off the current from.
the electro-motor circuit and send it through the brake actuating circuit on the-
completion of a definite movement of the device, substantially as set forth.
6. The combination with an electro-motor and a device to be moved thereby,.
and a circuit for conveying current to the electro-motor, of a clutch containing two.
revolving parts, said parts being independently revoluble at low speeds but held by.
centrifugal force so as to rotate together at high speeds, one of such parts being..
connected to the electro-motor and the other to the device to be moved, and of an,
electrically-actuated brake adapted to retard the movement of the device, and a
circuit for said brake,. and a switch operated by the moving parts to cut off the
current from the electro-motor circuit and send it through the brake actuating
circuit on the completion of a definite movement of the device, substantially as set.
forth.
7. The combination with an electro-motor and a device to be moved thereby,:
and a circuit for conveying current to the electro-motor of an electrically-actuated
brake controlling, when operated, the movement of said device and a circuit for
said brake, a switch operated by the moving parts to cut off the current from the
electro-motor circuit and send it through the brake actuating circuit on the
completion of a definite movement of the device, and a circuit breaker for closing.
and holding closed the path for said current, and also for cutting off said current,
whereby said circuit breaker will control the movement of said device, substantially
as set forth.
8. The combination of an electro-motor, a device to be moved thereby, a train of
gearing connecting said device and the electro-motor, a centrifugal clutch interposed
in said gearing, an electrically actuated brake adapted to retard the movement of
the device, and a switch operated by the moving parts to cut off the current from.
the electro-motor and send it to the brake on the completion of a definite movement.
of the device, substantially as set forth.
9. The combination with a pivoted arm of a train of gearing connected at its.
slow end to said arm, an electro-motor, a centrifugal clutch connecting the fast end
of the gearing to the electro-motor and a switch operated by the moving parts to-
cut off the current from the electro-motor at about the completion of the movement.
of the pivoted arm in one direction, substantially as set forth.
10. The combination with a pivoted arm of a train of gearing connected at its.
slow end to said arm, an electro-motor, a centrifugal clutch connecting the fast end
of the gearing to the electro-motor, an electrically-actuated brake arranged to be.
put in frictional contact with some revolving part at the fast end of the gearing,.
and a switch operated by the moving parts to cut off the current from the electro--
motor and send it to the brake on the completion of the movement of the pivoted
arm in one direction, substantially as set forth.
11. The combination with an electro-motor, its shaft and the radially sliding
grippers e, e, thereon, the flanged disc f and pinion g connected together and

page_text: mounted loosely upon said electro-motor shaft, the wheel h and pinion i, the wheel
and pinion k, the toothed sector and arm 1', a switch connected to said sector 1,
and an arm to be moved connected to said arm l, substantially as set forth.
12. The combination with an electro-motor and a device to be moved thereby,
and a circuit for conveying current to the electro-motor, of a revolving wheel
having an inner cylindrical surface and connected to said device, and revolving
grippers adapted to fit against the inner cylindrical surface of the wheel, and radia!
bearings in which said grippers are fitted to slide, said bearings being connected to
the electro-motor, an electrically actuated brake controlling, when operated, the
movement of said device and a circuit for said brake, a switch operated by the
moving parts to cut off the current from the electro-motor circuit and send it
through the brake actuating circuit on the completion of a definite movement of
the device, and a circuit breaker for closing and holding closed the path of said
current, and also for cutting off said current, whereby said circuit breaker will
control the movement of said device, substantially as set forth.
13. The combination with an electro-motor and a device to be moved thereby,
and a circuit for conveying current to the electro-motor, of a revolving wheel
having an inner cylindrical surface and connected to said device, and revolving
grippers adapted to fit against the inner cylindrical surface of the wheel and radial
bearings in which said grippers are fitted to slide, said bearings being connected to
the electro-motor, an electrically actuated brake controlling, when operated, the
movement of said device and a circuit for said brake, a train of gearing connecting
said wheel and the device to be moved, said device to be moved being at the slow
end of said train of gearing, a switch operated by the moving parts to cut off the
current from the electro-motor circuit and send it through the brake actuating
circuit on the completion of a definite movement of the device, and a circuit
breaker for closing and holding closed the path for said current, and also for
cutting off said current whereby said circuit breaker will control the movement of
said device, substantially as set forth.
Dated this 12th day of December 1893.
WILLIAM PHILLIPS HALL.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.