Improvements in and connected with Electric Brakes.
Year: 1895

page_text: Date of Application, 13th Aug., 1895-Accepted, 8th Feb., 1896
COMPLETE SPECIFICATION.
Improvements in and connected with Electric Brakes.
I, JAMES DEVONSHIRE, Secretary to The British Thomson-Houston, Limited,
of 38, Parliament Street, in the County of London, do hereby declare the nature of
this invention (which has been communicated to me from abroad by William B.
Potter, of Schenectady, in the County of Schenectady, State of New York,
United States of America, Electrical Engineer,) and in what manner the same is
to be performed to be particularly described and ascertained in and by the following
statement :-
1
My invention relates to electrically operated brakes for moving mechanism, and
more especially for mechanism propelled by electric motors, in which the motors
may be, in ways well understood in the art, converted into generators driven by the
momentum of the moving mass; the current from the motors may then be utilized
to operate brake-shoes of one form or another, which, in conjunction with the
magnetic resistance to the passage of the armature conductors through the field of
force, will operate to quickly arrest the motion of the car or other apparatus to
which the motors are attached,
Many forms of brake of the class described have been devised, some of which are
efficient and some not; in most of such forms with which I am acquainted, a single
handle has been used for operating both a motor controller of one type or another,
and the braking mechanism; this, however, I believe to be not an advantageous
disposition of the operating parts of the apparatus, .as I have found by practical
experience that where two or more motions are given to a single handle, the
operator is apt, in a moment of excitement, to give the handle the wrong movement
To avoid
and thus increase the liability to accident, instead of stopping the car.
this trouble, I have therefore arranged my mechanism with three operating handles;
one for the motor controller (which is preferably of the now well-known series-
parallel type,) and another for the electric braking mechanism; in conjunction with
these I employ the usual reversing switch for the motors, which, however, has no
part in the operation of the braking mechanism, except that it answers the same
purpose in relation to the brake switch that it does to the controlling switch; that
is, as applied to the power, it tenders it possible to run either forward or backward,
and as the brake switch needs to reverse the motor connections in order to be
operative, the action of the reversing switch is such that the brake operates in
either direction. I thus have upon the controlling stand three operating handles;
to prevent any accident by improper manipulation of the handles,
may and
preferably do arrange within the stand interlocking mechanism, presently to be
more fully described, by which it becomes impossible to operate more than one of
the handles at a time; that is to say, while operating the controller handle, the
reversing switch and the brake handle are locked in position; while operating the
brake handle the reversing switch and controller handle are locked, and while
operating the reversing switch, both the controller and the brake are locked. When
the handles of the brake and controller are at the off position, and the reversing
switch is at one of its two positions with the motors properly connected, it is
possible to operate any one of the handles desired, but, as already pointed out, no
two can be operated at any one time.
A modified form of my device will be more fully described in which I may employ
gearing by means of which the rotation of the controlling cylinder is gradually
retarded as it approaches the off position, where it is to be stopped, so that its

page_text: $
momentum does not give a hammer blow to the stop. This gearing also permits me
to so arrange the co-operating handles of the controller, (that is, the motor
controlling handle and the brake handle) that should the motorman in a moment
of excitement attempt to apply the brake without shutting off the controller, the
operation of the brake handle will bring the controller to its off position. In this
arrangement I have upon the brake cylinder a blank space over which the contacts
may travel, and this cylinder is constantly in rotation except when the handle is
idle. With this I also combine the usual reversing switch and a lock actuated by
this switch, so that, when this reversing switch is in its intermediate position, all
of the mechanism is locked against motion; only in this position is it possible to
remove the handle of the reversing switch. In either of the arrangements illustrated,
when the handles are removed, as when the motorman goes to the other end of the
car, the cylinders are locked in position and cannot be tampered with by
unauthorized persons.
A further feature of my invention will be found in the peculiar construction of
the brake-shoe which I have adopted; this consists substantially of a light truss,
preferably of wrought iron having a pair of segmental castings supported within it.
Within these segments I place the coils which are to energize the shoe, and by this
arrangement I obtain, without great weight, a strong and substantial shoe, which
is capable of being readily replaced, if necessary, and in which worn parts can be
easily renewed.
I also embrace within my invention a means for supporting the brake shoe
without adding to the equipment of the car. I have found this feature to be of very
great importance, inasmuch as many forms of truck, when equipped with brakes of
other constructions, 'require the addition of cross-bars or other devices for supporting
the brake; or preventing the rotation of the shoe. This has limited the usefulness
of some forms of brake, which require special constructions, whereas, by my
improved method of support I am enabled to adapt my brake to any form of truck
now upon the market. The support consists in placing the brake-shoe directly upon
the gear casing adjoining the motor or upon some part of the motor itself; for
which purpose I provide upon the gear casing or motor suitable lugs to take the
strain; at the same time I support the weight of the shoe to a greater or less extent,
as desired, upon springs, which permit it to have a certain small amount of play, and
which also act not only to relieve the shoe and bring it away from the disc against
which it bears when the brakes are released, but to lessen the friction of the shoe
upon its bearings. For the former purpose I arrange the springs at a slight angle
to the face of the disc and shoe, and attach them also to the gear casing of motor.
The attachment of the brake shoe to the motor directly is of peculiar importance in
the form of motor known as "gearless," in which the armature is supported upon a
sleeve surrounding the axle; inasmuch as in this form of apparatus, the amount of
room between the vehicle wheel and the armature is extremely limited.
My invention further consists in an improved method of providing for the braking
cylinder a inagnetic blow-out, which consists in connecting a coil directly between
two of the contacts upon the cylinder, and thus energizing the shaft about which it
turns as a pole-piece for the magnet. The iron frame supporting the arc deflector
forms a second pole, the magnetic field being between this iron and the shaft of the
cylinder. The yoke piece of this magnetic circuit is that part of the deflector
frame which turns over the end of the cylinder and embraces the shaft; while the
controller frame itself assists the magnetic action. I may also divide the shaft
just referred to by a piece of non-magnetic metal and duplicate the coil, so that,
where I employ cut-out switches, as hereinafter referred to, the shaft and controller
frame may form a horse-shoe magnet which will act with sufficient energy to
extinguish any ate that may be formed.
My invention further consists in the combination, with the series-parallel
controller to which I have referred, of certain cut-out switches permitting me to
operate my improved electric brake with only one of the motors in circuit, without
materially affecting its efficiency.

page_text: Furthermore my invention consists in a mechanical locking device by means of
which when the brake shoe and the disc against which it bears are brought into
engagement by the operation of the electrical part of the apparatus and the car has
been brought to a stop, the shoe and dise are mechanically locked together and
rotation is absolutely prevented. This I obtain by a mechanism acting upon the
principle of the ring-clutch, normally held in a central or open position, but which
is drawn up either by the action of the brake-controller at its last position or other-
wise, so as to just engage the brake-shoe and the braking disc. If the disc (which
is fast to the axle) then starts to rotate, it engages with one side of the clutch and
draws it forward, dragging against the brake shoe and effectually locking the two
together. As it would be disastrous to the apparatus to allow such absolute lock
to be put on while it is in motion, I control its operation by, and preferably arrange it
to be operated by the same handle as, the electric brake; aud inasmuch as there is
always more than enough power in the electric brake to lock the wheels when
necessary, it is evident that by arranging the lock to come on when the brake
handle passes its last position, any risk of its being applied while the wheels are still
rotating is obviated." For this I may substitute or with it I may combine a
magnetic locking arrangement consisting of a coil located in or upon the brake-shoe,
and directly in the circuit from the trolley to ground, which is brouglit, into action
by the last step of the brake handle, so that, after the car is brought to rest, this
coil, in conjunction with the friction of quiescence, will be sufficient to keep the car
at rest. The coil is usually of high resistance.
In conclusion, my invention consists in sundry details of improved construction
which will be more fully described hereinafter, and specifically pointed out in the
claims annexed to this Specification.
In the accompanying drawings, hereby referred to and made part of this Specifi-
cation, like letters refer to like parts throughout; and therein
Fig. 1 is a front elevation, partly in section and partly broken away, of my
impiosed controlling stand, adapted to the purposes of my invention;
Fig. 2 is a plan view, also partly in section and partly broken away, of the
interlocking arrangements to which I have referred ;
་
Fig. 3 is a similar view of the modification referred to in my statement of
invention, employing a single handle for the controller and the brake cylinder;
Fig. 4 is a front elevation of the parts shown in Fig. 3;
Fig. 5 is a detail of the lock on the reversing switch;
Figs. 6 and 7 are a side elevation and end elevation respectively of the improved
support for the brake shoe which I have devised, and also illustrate the mechanical
locking mechanism already referred to.
Fig. 8 is a detail of the mechanical lock showing it in plan with the means for
effecting its release ;
Fig. 9 is a section on line 9-9 of Fig. 6 of the cast part of the brake-shoe
which 1 employ;
Figs. 10 to 13 show the connections of the mechanical lock and the brake switch
cylinder;
i
Fig. 14 is a diagram illustrating the circuits upon an
invention applied thereto;
electric car with my
Fig. 15 is a diagram showing in simple form the arrangement of the circuits;
Fig. 16 is a diagram showing the combination of my improved brake with cut-out
switches adapted to permit of its operation when either one of the motors is cut
out, and
.
Fig. 17 is a diagram illustrating the motor combinations of the last figure.
I will first describe the mechanical construction, as illustrated in Figs. 1 to 13,
and will then take up and describe the electrical actions as illustrated diagram-
matically in the other figures of the drawing.
Referring by letter, in Fig. 1, A is the frame of the controller; B, B1, B2 are
the operating handles; a portion of the cover is shown at A3; C is the controlling
cylinder, the contacts and cross-connections of which are illustrated in Fig. 14.

page_text: C¹, C', &c., are the fixed contacts co-operating with the sliding contacts upon the
cylinder C. D is the reversing switch, the electrical connections of which are
shown in Fig. 14. E is a brake cylinder or braking switch, provided, as are the
other cylinders, with the usual contacts. The shaft of this switch, as shown in
dotted lines, is divided into three portions, E³, E³, and E. The portions E³, E³ are
of iron or steel, while E is of brass or other non-magnetic metal. As pointed out
in my statement of invention, the object of this division is to make the shaft and
the yoke E supporting the arc deflectors E, E, form a magnet of sufficient
strength to blow out any are that may be formed upon the cylinder contacts. The
pole-pieces E³, E³ are energized by the coils E', E¹. These coils are wound
directly upon the surface of the cylinder and are connected, as illustrated in Fig. 14,
between those contacts which are last in circuit, so that they may be energized at
all times or substantially at all times. F is the blow-out magnet coil of the main
controller cylinder, and F' is the pole-piece carrying the arc-deflectors F2, F2.
This pole-piece is mounted in bearings f, f and is secured in position by the lag
screw, as illustrated in my Patent above referred to. G', G₁ are the cut-out
switches customarily employed with a series multiple controller. The fixed contacts
of fingers co-operating with the cylinder E are not illustrated, they being at the
side of the cylinder.
Referring now to Fig. 2, in connection with Fig. 1, I illustrate the interlocking
arrangement to which I bave referred. Therein H is a star wheel co-operating
with a cam roller (not illustrated) the wheel being affixed to the controller
cylinder C; this serves to give the usual step-by-step motion to the cylinder.
The notches h, h are designed for the reception of the cam roller. L is a bolt
provided with an end / adapted to fit into the notch or stop upon the controlling
cylinder. Attached to the reversing cylinder is a cam I provided with notches i, i, i.
A pawl having a cam roller upon its end co-operates with the cam I. The back
of the cam I, as illustrated in dotted lines at I, is formed to afford a stop or lock
for a pawl K³, also presently to be again referred to. These two pawls, K³ and 2,
have pins projecting into slots L³, L2, upon the bolt L. Attached to the brake
cylinder is a star wheel K provided with notches k, k, &c., in which the cam roller
upon the pawl K' operates. Suitable springs, M, M, M draw back the pawls ²
and K' and the bolt L.
is
The operation of the parts described is as follows: When the controller
cylinder C is rotated, the cam or star wheel H rotates with it, and the notch
out of alignment with the end of the bolt L. It is then impossible to actuate the
reversing switch, because the pawl locks the cam I in position. It is also
impossible to actuate the brake switch because the pawl K' locks the cam K in
position, both of these pawls being held by the slots L2, L' in the bolt L, the end of
which no longer registers with the notch or stop ', so that the bolt itself cannot move.
When the controller handle is at the off position, either of the handles B¹, B³ may
be actuated. Assume now that the reversing switch handle B' is actuated, as soon
as the notch i engages with the roller upon the pawl, the bolt L is thrown forward
into the notch 1, thus locking the controller cylinder, while the part 1 of the
cam I engages with the pawl K, and locks the brake cylinder in place. As, soon,
however, as the pawl 2 drops into either one of the notches i,, the parts are again
free to move. Similarly, if the handle B2 be actuated, the cam K forces the
pawl K³, thrusts the end of the lever L into the notch ', thus locking the controller
cylinder, and the pawl K itself approaches so close to the part 1 of the cam I
that the reversing switch cylinder cannot be rotated sufficiently in either direction
to actuate its contacts.
Referring now to Figs. 3 and 4, I illustrate the modification referred to in my
statement of invention, by which the brake handle may be made to return the
controlling switch to the off position before it operates the braking cylinder.
Therein, as before, C is the controlling cylinder and E is the braking cylinder.
Upon the controlling cylinder is mounted a pinion P co-operating with the rack O
Attached to a gear P₁ is a crank O and a connecting rod O', jointed at 04 to the

page_text: ack O. Upon the under side of the rack is a guide roller o co-operating with
the guide 03. Meshing with a gear P² operating the braking switch cylinder is
the other gear Preferred to above. At 05 is a stop co-operating with a notch O
upon the ack O. Dis the reversing switch cylinder, which, in the case illustrated,
is operated by levers N, N', N. The cam 1 in this case is situated upon the shaft
of the handle B, instead of upon the cylinder shaft, the construction being other-
wise unchanged. The bolt a co-operates with the notch n' upon the brake cylinder,
which is geared to the controlling switch, and as before, when the handle B¹ is
operated, the bolt n is thrust into the notch n', and the whole apparatus is locked.
The handle B' may then be removed, and it will be impossible to operate the
controller until the cam I is thrown to one side of its central position. When the
apparatus is free to turn, however, the rotation of the handles B1, B2, shown in
dotted lines in the figure, operates the gears P1, P2, and when the handle B is
carried to the left, will rotate the controller cylinder C in the usual way by the
rack O and the pinion P. When the handle, however, is carried to the right, the
controller cylinder C will be rotated by the rack and pinion until the notch 0°
upon the rack strikes the stop 0', when this cylinder will cease to rotate; as will
be observed from a study of the drawing, the motion of the rack longitudinally
becomes less and less, the more nearly it gets into alignment with the crank arm
operating it; when the two are at a right angle the motion of the rack being the most
rapid. This, as pointed out in my statement of invention, retards the cylinder C
so that when the notch O finally strikes the stop, the momentum of the cylinder
has been very much checked and the blow is not as severe as it would otherwise be.
During the time that this cylinder is rotated, the cylinder E is also of course being
rotated; but during this part of its rotation the fixed contacts bear upon the
insulating or idle portion of the cylinder. When the notch O, however, strikes
the stop, and the controller cylinder C is brought to its off position, the connections,
as more fully described hereafter, are made between the fixed contacts and the
contact-plates or strips upon the cylinder effecting the braking combinations. The
further rotation of the handle B to the right actuates the brake in the usual way,
the crank and the connecting rod O¹ being free to continue their motions, by
reason of the jointed connection O' with the rack O³.
•
It is of course manifest that this arrangement may be reversed, and the controller
cylinder may bring the brake cylinder to the off position; or
may arrange the
controller cylinder and the brake cylinder to gear into each other by circular
gears, or by such form of gearing (as an elliptical or figure of eight), as will affect
the reduction of speed of rotation in the way already described with reference to
the rack and pinion. In case the two circular gears are used, however, this
reduction of speed is not effected, but I may, if preferred, so arrange the apparatus,
and dispense with this feature without departing from the principles of my invention.
Figs. 6 to 9 show both the improved form of brake shoe which I have devised
and also the method of mounting it heretofore briefly referred to.
Therein U 18
the car axle; U¹ is the gear case of the motor, and R is, as in the other figures,
the brake shoe. In the other figures I have illustrated this shoe diagrammatically in
a form now well known, but the present figure shows that which I prefer; and in
that R' is a fiame, preferably of wrought iron, and V, V₁ are segmental castings
provided with coil chambers v, v and interior cores V2. The frame R' is secured to
these segments by bolts R².
Referring to the same figures, the attachment of the shoe to the gear casing
is illustrated at R³. U, U are lugs cast upon the gear case, and r, rare parts
of the frame already referred to, which are secured to the castings V, V₁ at
a little distance apart so as to permit the lugs U2 to make just a working fit
between them.
In the same figures, taken in conjunction with Figs. 8 and 10 to 13, I show
at X the locking device to which I have already referred. Therein Z is a lever
carrying an eccentric Z upon a shaft Z' mounted in the top of the brake-shoe.
X is a removable pin secured in the lug X; as the principal wear of the lock

page_text: comes upon this pin, it is made removable so that a new bearing may be
provided at any time, the head a being also removable for this purpose. R is, as
before, the brake shoe, of which the frame R' is shown in Fig. 7, and Y is a disc
fast upon the axle. As illustrated, the face of the brake-shoe and the disc are
closely approximated, and when the current is turned on in the coils occupying
the coil chamber v, v the brake-shoe becomes strongly magnetic, and attracts the
disc; which, being fast to the axle, acts to draw the brake-shoe towards it, the
parts r,sliding upon the lugs U2; the friction of the disc and the brake-shoe, in
conjunction with the resistance to rotation of the motor armatures, soon stops the car.
Just at this moment the lock is thrown on by the motorman, by suitable mechanism
drawing the shaft Z' carrying the eccentric around upon its axis, and bringing up
When the
the lug X and the bearing of the bolt ✗₁ against the disc Y.
magnetic attraction dies away (which, however, takes some time, inasmuch as the
brake as a whole becomes somewhat like a transformer and the magnetism in dying
out sets up new currents in the disc and shoe, this tending to prolong the magnetic
field), then the shoe and dise are still held in close engagement by the lug X, and
upon any tendency to rotate, this engagement is made still closer, as the part x is
drawn around in the direction of rotation by the disc Y, and is thus brought up
firmly against the brake-shoe, its operation being like that of the well known ring-
-clutch in electric arc lamps and other devices. The parts just described are also
illustrated in another view in Fig. 8, from which the action just pointed out will be
rendered more clear.
As
Referring now to Figs. 10 and 11, I show the application to a car of the
mechanical lock I have devised, with the means connected with the controller
adapted to prevent the operation of the lock until the brake is fully set.
already pointed out in my statement of invention, it is necessary that the wheels
should be locked or moving at so slow a rate as to be practically locked, before the
actual mechanical locking occurs; otherwise, (that is, if the movement beat too
great a rate of speed) the absolute locking of the disc and brake-shoe may cause
injury to the apparatus.
As
In these figures, X is, as before, the lock; U is the car axle, W' the wheels,
and U the gear case of the motors. Connecting the lock with the braking switch
is a rod g provided with a turn buckle g² for taking up the slack in the rod.
illustrated in Fig. 10, only one lock is employed, adapted to be set from both ends
of the car ordinarily this will be quite sufficient. A is, as before, the controller
case, and B the controller handle; B2 being the handle of the braking switch.
The shaft of the braking switch extends, as will be readily understood, through
the cylinder and through the platform of the car. To the bottom of this shaft is
attached a crank B' and a pm on this crank operates in the slotted end g¹ of the
10d g.
As illustrated, it will be seen that there is a certain amount of lost
motion in this slotted end, so that the braking switch handle B' may be turned
for a definite distance before the lock is actuated. Thus the brake will be fully set
and the wheels will have ceased to turn before the lock is put on.
The arrange-
ment shown in Fig. 11 is substantially like that in Fig. 10, except that a lock is
provided for each axle, and each controller operates its own lock. It is manifest
that the two locks may be connected if desired, and each controller operate them
both, but as this is merely a mechanical feature, it will not be further illustrated or
described. It is further manifest that it is immaterial whether the lock is operated
by compression upon the rod g or extension thereof, as this may be accomplished
merely by turning the arm B upon the shaft into one or another position, as
may be required. For instance, in the right hand controller of Fig. 10, the rod
is operated by extension, while in the left hand controller it is operated by
⚫compression.
In Figs. 12 and 13 I illustrate a modification which may be employed and still
be within my invention. In this modification a treadle is so arranged that it can
only be operated after the braking switch cylinder has been tuined to its last
"tumbler "
position, a stop upon the treadle co-operating with the notched disc or

page_text: upon the braking switch, and the notch being in alignment with the stop only in.
the last position of the switch. In these figures, is, as before, the rod leading to
the lock, the other parts being the same as in Figs. 10 and 11. 9 is a crank
affixed to the shaft and operating the rod g. 9 is another crank also affixed to
the shaft and operating the stop g which co-operates with the notched disc or
tumbler B, separately illustrated in Fig. 13. A treadle g' projects above the car
platform is a relieving or centralizing spring adapted to assist the centralizing
springs upon the lock proper, as illustrated in Fig. 8. This spring may be omitted
if desired. One side of the treadle post is divided with teeth co-operating
with the fixed pawl g' upon the platform. A lever g¹º connects the treadle g' with
the shaft g*.
The operation of the parts described is apparent; that is to say, when the notch
in the disc B³ is opposite the stop g, the treadle g may be depressed and the teeth,
will engage with the pawl g°. A slight amount of lost motion is left in the opening
through which the tieadle post passes, and when it is desired to disengage the
teeth from the pawl, the treadle is merely pressed forwards and the spring, in
conjunction with the springs upon the lock proper, will raise it and release the stop
and lock.
It will be readily understood that this arrangement affords not only a safety
provision against putting on the lock when the brake is not in its last position. but
also prevents the brake being thrown off or the power applied until the lock has
been released, as the stop 9 prevents the rotation of the handle B
The arrangement of circuits which illustrate in Fig. 14 has advantages in the.
saving of wire and of labour in car wiring. It consists substantially in the
combination of a series-parallel switch (preferably such as that described in my
Patent above referred to), a reversing switch, which may be of any suitable form,
and a baking switch which prefer to have of the form described, but which may
be of other forms. The braking switch is provided with a pair of auxiliary
contacts, presently more fully described, through which encuits are made between
the trolley and the motors through the series-parallel controlling switch by the
arrangement of these contacts I ar: enabled to save considerable wire, as above
pointed out. The same letters are used in this as in the other figures so far as they
are applicable; but, referring further by letter, P3 P4 are the motors, of
which A. A are the armatures, and F M, F M³ the field-magnets respectively.
T is the trolley; R is, as before, the brake-shoe. Some of the circuits are
completed through the iron framework of the controlling stand, which I have
indicated in appropriate places by the letters "C F," indicating controller frame.
This controlling frame is customarily connected to the ground wire of the motors,
that is, grounded upon the truck in some suitable way. From one controller frame
to the other, however, is a perfect metallic circuit, irrespective of the connection.
with the ground, which may be said in a sense to be merely an auxiliary safety
connection. S, S¹, S are the resistances employed in the running of the car in its.
ordinary course, while Q is, as before, the auxiliary resistance which I prefer to
use to regulate the current flow in the brake magnet when the motors are operated
as generators.
When the motors are running the car, the first position is in series with all
of the main resistance S in circuit; and in this position the course of the
current is as follows; entering by the trolley T, it passes down the lead 35 to
the lead 57, thence to the contact brush 26, upon the controller C at the bottom of
the figure; then to contact-plate 26°, thence by cross-connection to contact plate 27",
to contact 27, to lead 59, thence through the resistance S, going in this position
through the entire resistance, to the lead 61, following this lead to contact 25
upon the reversing switch D in the upper right-hand part of the figure, thence
to contact-plate 24°, thence to contact 24, thence by the lead 52 and lead 39-
to the armature A', thence through the armature, by the lead 38, to lead 54,
thence to contact 14 upon the brake switch E, to contact-plate 14, by cross-
connection to contact-plate 13b, then to contact 13, then to contact 23 upon the

page_text: reversing switch D, then to contact-plate 22ª, then to contact 22, then to lead 51,
to lead 37, through the field-magnet FM' of the motor P³, through the lead 36, to
the lead 56, to contact 32, to contact-plate 32, by cross-connection to contact-
plate 30°, to contact 30, to the lead 48, to contact 21 upon the reversing switch D,
to contact-plate 20ª, to contact 20, to the lead 50, through the lead 41, through the
armature A2 of the motor Pt, through the lead 40, to the lead 53, to contact 10
upon the brake switch E, to contact-plate 10b, by cross-connection to contact-
plate 11b, to contact 11, to contact 19 upon the reversing switch D, to contact-
plate 18, to contact 18, by the lead 49, through the lead 42, through the field.
magnet FM of the motor P4, and by the lead 43 to ground. As will be seen, this
combination gives the resistance in series with the two motors, which are also in
series.
The operation of the brake is not dependent, upon the trolley current in any
sense; the first step in the rotation of the brake switch when moved from its off
position, in which the contacts 10, 11, 13 and 14 rest respectively upon the contact-
plates 10, 11, 13, 14b, serves to complete the local circuit with the motors in the
way indicated diagrammatically in Fig. 15; that is to say, the two armatures and
the brake-shoe are in series, the two field-magnets are also in series with the
armatures, being connected through the controller frame, and are in shunt to the
resistance Q. It will be readily understood that at first the field-magnets are
shunted by wire of extremely small resistance and that as progressive steps of the
resistance Q are cut in, these field-magnets take more and more current, and
the current supplied to the brake-shoe R becomes larger and larger and of higher
electro-motive force. The circuits which affect this combination are as follows;
starting from the armature A² and from the brush upon the left side of the
armature, as indicated diagrammatically, the current would pass by the lead 40 to
the lead 53, to the contact 10, contact-plate 10", by cross-connection to contact-
plate 9, contact 9, to the lead 52, by the lead 39 to the armature A', through the
armature by the lead 38, to the lead 54, to contact 14, to contact-plate 14ª, through
the coil E of the blow-out magnet acting as a cross-connection to the contact-
plate 15, to contact 15, to lead 55, through the brake-magnet R by the lead 45,
and from the brake-magnet by the lead 44 to the lead 56. At the point 56ª the
current divides, one path being by the lead 36, through the field-magnet FM', of
the motor P³, to the lead 37, to the lead 51, to contact 12, to contact-plate 12", and
to the controller frame. Re-entering at the controller frame, as indicated, through
the lead 43 from the field magnet FM2, it passes through that field-maguet by the
lead 42 to the lead 49, thence to contact 2 upon the brake switch cylinder, to
contact-plate 2, through the blow-out magnet coil E¹, the contact-plate 1", to
contact 1, to lead 50, and by the lead 41 to the other side of the armature, passing
through which completes the local circuit. The other path from the point 56 to
which the current comes after passing through the brake-shoe, is in the opposite
direction, or to the right, through the lead 56, to the contact 3, and, in the first
position of the switch E, to the contact-plate 3", rejoining the other path of the
current upon the contact-plate 2º. This is the shunt of practically no resistance
already referred to; it will.be evident, however, that as the switch is rotated and
the contacts 3 to 8 pass off the contact-plates 3ª, 4", &c., more and more of the
resistance Qwill be cut in, through which the current must pass before reaching
any of the contact-plates and then passing by the cross-connection to the contact-
plate 2, until finally, when the contact 8 leaves the contact-plate 8, this shunt
circuit is opened and the entire current passes through the fields, as will be readily
understood upon an examination of the contacts and connections in Fig. 15.
Passing now to Fig. 16, I illustrate how my improved brake may be combined
with the series multiple controller designed to effect the regulation of the motors in
the way pointed out, and with cut-out switches, so that either one of the two motors
preferably and usually employed in this method may be cut out, and still the brake-
magnet coils will be supplied with current from the remaining machine and the
brake mechanism will not be disabled. In this diagram the same letters refer to

page_text: the same parts as in previous figures, but in addition I show the cut-out
switches CO, CO. These are preferably located in the usual places upon the
series-parallel controller. I have indicated with short lines the usual connection
of these switches in that controller; and as the operation in the ordinary use of the
electric apparatus as motors is not modified by their use in this special combination,
I do not further describe it in that relation. As represented, the motors act as
generators upon a local circuit closed by the contacts 2 to 17, touching the contact-
plates 2d, &c. upon the cylinder. Starting from the armature A', the current
proceeds in the direction indicated by the arrow, first to the contact 4, then to the
contact-plate 4, by cross-connection to the contact-plate 5, to the contact 5, then
to the point 64, then down the lead from the point 64 to the cut-out switch CO² at
its contact 53b, then to the contact 53, then by the lead through the field-magnet F M'
to the controller frame, as shown in the upper left hand corner of the diagram.
Re-entering from the controller frame, as indicated in the lower right-hand corner
of the diagram, the current passes to the contact-plate 15", then to the contact 15,
then by the lead through the field-magnet FM, then to the point 63; from the
point 63 two paths are open to the current, one by the lower lead to the contact 14,
to the contact-plate 14ª, by cross-connection to the contact-plate 13", to the
contact 13, to the armature A', passing through the armature, then by the lead to
the cut-out switch CO', entering at the contact 51, then to the contact 51, by the
lead to the contact 16, contact-plate 16, through the blow-out coil E¹, to the
contact-plate. 17, then to the contact 17, then through the brake-magnet R to
the contact 3, to the contact-plate 3, through the blow-out magnet coil E', to the
contact-plate 2ª, to contact 2, by the lead to the cut-out switch C O at the contact 54,
then to contact 54 and by the lead back to the armature A2, thus completing the
local circuit. The resistance Q is included in the other or shunt path from the
point 63, as follows: Passing to the cut-out switch CO' at contact 50 to
the contact 50, then by the lead to contact 6, to contact-plate 6d, to contact-plate 5ª,
to contact 5, to the point 64, then by the lead to the cut-out switch CO2 at the
contact 53b, then to contact 53 and then by the lead to the field-magnet F M2; thus,
as will be seen, shunting the resistance around the two fields F M², FM2. As before
the rotation of the switch cuts in section of resistance as the contacts 6, 7, 8, &c.,
pass from the contact-plates 6, 7, &c., until finally when the contact 11 passes
from the contact-plate 11d the shunt is opened, and the entire current passes
through the fields.
Assume now that the cut-out switch C O' is thrown up until the lower
contacts 47, 48, 49, 50 and 51 are open-circuited, and the contacts 47, 48, 50ª, 51",
are connected to the switch. This open-circuits the armature A' at the cut-out
switch CO. In this position the contacts 49 and 49" will not be referred to,
inasmuch as, as already pointed out, they have no office in connection with the
brake, but only operate to cut out the electric apparatus when acting as motors, in
a way well understood in the art. Following the lead from the night hand side of
the armature, it will be seen that, as it passes through the reversing switch D'
(the reversing switches being indicated diagrammatically at D, D, 'D', D' and
having no office in the combination of circuits described in this figure) it passes to
the contact 47 upon cut-out switch C O¹, and is there open-circuited, as the switch
is in its upper or dotted line position. Following now the lead to the right of the
eversing switch, it passes only as far as the contact 51 upon the same cut-out
switch, and there it also is open-circuited. It is unnecessary to trace the connections
to the other side of the armature, inasmuch as no current can flow in the open
circuit.
The path of the current from the armature A² as modified when the armature A'
s cut out, is as follows: Starting from the right side of the armature, as before, it
passes by the lead to the contact 4, to the contact-plate 4", by cross-connection to
contact-plate 5", to contact 5, to the point 64, by the lead to the contact 53 up a
the cut-out switch CO2, to contact 53, then by the lead through the field-
magnet F M² to the controller frame. Entering from the controller frame to
B

page_text: the cut-out switch CO', it passes to the contact 51, then to the contact 51b, by
the lead to the contact 16, to contact-plate 16 upon the switch E through the
blow-out coil E¹ to the contact-plate 17d, to contact 17, through the brake-shoe R,
to the contact 3, to the contact-plate 3ª, through the blow-out coil E', to the
contact-plate 20, to contact 2, to contact 54 upon cut-out switch CO³, to
contact 54, and by the lead to the other side of the armature A2, thus completing
the local circuit through the field-magnet FM2 and the brake-shoe R. The
resistance is, as before, in shunt circuit around the field-magnet and its circuit
starts from the contact 51 upon the cut-out switch CO¹, by cross-connection to
contact 50%, to contact 50%, by the lead to the contact 6, to contact-plate 6, by
cross-connection to contact-plate 5", to contact 5, to point 64, by the lead to
contact 53 upon the cut-out switch CO2, thus rejoining the circuit at a point
between the aimature A2 and the field-magnet F M². This circuit is illustrated
diagraminatically in Fig. 17, which will be understood without further description;
this Fig. 17 also illustrates in substantially the same way the circuit when the
cut-out switch CO2 is thrown, as now to be described, the only difference being in
the identity of the motor cut out.
Assuming that the cut-out switch CO¹ is in its illustrated position and that the
cut-out switch CO2 has been thrown to that shown in dotted lines, cutting out
motor No. 2, the circuits will be as follows: Following the lead from armature A
towards the left, it will be found to be open-circuited at contact 54 upon cut-out
switch CO2. The circuit of this armature will not be further traced, inasmuch
as, as before pointed out with reference to armature A¹, it being open-circuited at
one point, no current will flow. The circuit from armature A is as follows:
Passing to the lead upon the right hand side of the armature, the current passes
to contact 51 upon the cut-out switch CO', to contact 51b, by the lead to contact 16
on the switch E, to contact-plate 16, through the blow-out coil E', to contact-
plate 17 to contact 17, through the brake-shoe R, to contact 3, to contact-plate 3ª,
through the blow-out coil E to contact-plate 24, contact 2, to contact 54 upon
the cut-out switch CO, to contact 54, and to the controller frame. Entering
from the controller frame at the switch E, it passes to the contact-plate 15", to
contact 15, by the lead through the field-magnet FM, thence to the point 63;
here the current divides, the main circuit being from the point 63, by the lead
to the contact 14 upon the switch E, to contact-plate 14, to contact-plate 13ª, to
contact 13, and by the lead to the other side of the armature A', thus completing
the circuit as illustrated in Fig. 18, through the brake-shoe and field-magnet, using
the controller frame as part of the circuit. The other path of the current is the
shunt containing the resistance, and, as before, is from the controller frame to the
cut-out switch CO2, to the contact 54, by cross-connection to contact 53º, by
the switch-blade to contact 53b, by the lead to the point 64, to contact 5 on the
switch E, to contact-plate 5, by cross-connection to contact-plate 6", to contact 6,
by the lead to the contact 50° upon the cut-out switch CO, by the switch-blade
to contact 50, rejoining the main circuit at the point 63.
It will be seen that when the cut-out switches are operated, the current will
pass in relatively opposite directions through the brake-maguet R as the respective
switches are thrown. This has no practical effect upon the braking mechanism
as a whole, as its operation is equally effective in whichever direction the current
passes.
In each of the circuits as traced through the cut-out switches in their dotted line
positions, it will be understood that the shunt is at first a direct short circuit, as
already pointed out with reference to the operation of the braking mechanism
when both motors are acting; and that more and more resistance is cut in by the
rotation of the switch E and the operation of the contacts 6, 7, 8, &c., until the
shunt is open-circuited and the entire current passes through the field.
It is manifest that changes may be made in the arrangement of circuits and
apparatus which I have devised, without affecting the application of my invention.
So far as I am aware, I am the first to utilize the controlling frame as part of the

page_text: circuit of the electric braking mechanism; and as by this step I obtain, as already
pointed out, a very considerable economy in installation of apparatus, I wish to
make broad claims thereto. I am also the first to so combine a plurality of motors
and a braking mechanism that the brake will be operative with either one or two
motors. I also employ the diagrammatic representation of the brake-shoe R as a
convenient way of illustrating either one or a plurality of brake-shoes, as it is
manifest that two or more brake-shoes may be employed either in series or in
multiple, or if there be more than two, in multiple series or in any other com-
bination. I may also employ both the mechanical lock which I have shown, and
my improved electric lock in the same apparatus, or I may so arrange it that
the mechanical lock may be actuated upon the failure of the electric lock or
vice versa, without affecting my invention. All such formal variations I aim to
include in the claims appended hereto.
I also wish to claim broadly herein the combination of a series-parallel switch
and a brake-switch, with contacts upon the brake-switch connecting with the
series-parallel switch directly; asmuch as by this arrangement (as in the case
of using the controller frame as part of the circuit), I save considerable expense
in the wiring of the car. Therefore the claims I shall make to the combination
of a series-parallel switch and brake-switch, as above pointed out I wish to be
construed broadly.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an electric braking mechanism, a controlling switch for the electric motors,
a brake-switch, a reversing switch, and means adapted to prevent a simultaneous
operation of any two of the switches.
2. In an electric braking mechanism, a controlling switch, a reversing switch, a
brake switch, and means adapted to prevent the operation of the reversing switch
and the brake switch while the controlling switch is being operated.
3. In an electric braking mechanism, a controlling switch, a reversing switch
and a brake switch, and means adapted to prevent the operation of the controlling
switch while the reversing switch is being operated.
4. In an electric braking mechanism, a controlling switch, a reversing switch
and a brake switch, and means adapted to prevent the operation of the reversing
switch and the controlling switch while the brake switch is in operation.
5. In an electric braking mechanism, a reversing switch, a controlling switch
and a brake switch, and interlocking mechanism between the reversing switch and
one of the other switches, the other switches being connected.
6. In an electric brake, a controlling switch and a brake switch, and means
connecting the switches arranged to cause the operation of one of them to always
bring the other to the off position before the actuated switch is brought into
operative position.
7. In an electric brake, a controlling switch, a brake switch, and gearing
connecting the two switches and arranged to always bring one of them to an
off position by the operation of the other before the operated switch affects the
motor circuits.
8. In an electric brake, a brake switch, fixed contacts, co-operating therewith,
an idle portion and operative contacts upon the brake switch, a controlling switch
similarly provided with fixed contacts, operative contacts, and an idle portion,
and connecting mechanism between the two switches; whereby the fixed contacts
of one switch are upon the idle portion of that switch while the fixed contacts of
the other switch are upon the operative contacts of that switch, and vice versa.
9. In an electric brake, a cylindrical controlling switch having operative
contacts and a blank portion upon the cylinder, fixed contacts co-operating with
the controlling switch cylinder, a cylindrical brake switch similarly arranged fixed
contacts co-operating therewith, and mechanism adapted to bring the fixed

page_text: contacts upon one switch over the blank portion of the cylinder when the fixed
contacts of the other switch are upon the operative contacts upon its cylinder, and
vice versa.
10. In combination, a plurality of switches, and mechanism adapted to always
bring one switch to the off position by the operation of the other.
11. In combination, a plurality of switches, and mechanism connecting them
adapted to bring part of them to the off position while permitting the further
movement of the remainder.
12. In an electric brake, a controlling switch, a brake switch, and co-operating
mechanism adapted to bring the controlling switch to rest at its off position while
permitting the further rotation of the brake switch.
13. In an electric brake, a controlling switch, a brake switch, and co-operating
mechanism adapted to retard the movement of the controlling switch as it
approaches the off position while permitting the further movement of the brake
switch.
14. In an electric brake, a controlling switch, a brake switch, and co-operating
mechanism adapted to progressively retard the movement of the controlling
switch as it approaches the off position while permitting the further movement of
the brake switch.
15. In an electric brake, a brake switch, a controlling switch, mechanism
connecting the two switches, a reversing switch having a handle removable in one
position only, and an interlocking mechanism adapted to lock the brake switch and
controller by the movement of the reversing switch to the position in which its
handle may be removed.
16. In combination, a motor gear-casing, a brake-shoe, and means for supporting
the brake-shoe upon the gear casing.
17. In combination, a motor gear-casing, a brake-shoe, lugs upon the gear-casing,
and co-operating parts upon the brake-shoe adapted to engage with the lugs.
18. In combination, a motor gear-casing, a brake-shoe upon the gear casing, and
springs between the casing and the brake-shoc.
19. In combination, a motor gear-casing, a brake-shoe, means for supporting the
brake-shoe upon the casing, and springs connecting the casing and brake-shoe at an
angle to the plane of the shoe.
20. As a new article of manufacture, a brake-shoe for an electric braking
mechanism, composed of an iron frame and segmental blocks supported therein
provided with coil chambers; the frame being made in portions spaced apart and
adapted to engage with supporting means for the shoe.
21. In a braking apparatus and in combination, a rotating disc affixed to the
axle of the car, a brake shoe co-operating therewith, and a mechanical clamp or
clutch adapted to hold the two in engagement, substantially as described.
22. In combination, a rotating disc affixed to the car axle, an electro-
magnetically operated brake-shoe, and a clamp or clutch co-operating therewith,
arranged to hold the two parts in engagement after the cessation of current.
23. In a braking mechanism and in combination, a rotating disc affixed to the
car axle, a brake-shoe co-operating therewith, and a clutch comprising a bar
having a lug at a right angle thereto, and means adapted to take up the play
between the lug and the side of the disc or to release the lug, substantially as
described.
24. In combination, a rotating disc affixed to the car axle, a brake-shoe, a
clamp comprising a bar having a lug at a right angle thereto, means for taking up
the play between the lug and the disc or for releasing the lug, a braking switch
upon the car, and a connection between the clutch and the switch, whereby the
clutch is operated in the last position only of the switch.
25. As a means of providing a magnetic field adapted to extinguish arcs at the
contacts of a switch cylinder, a coil connected between two of such contacts, and
adapted to polarize the shaft of the cylinder.
26. As a means of providing a magnetic field adapted to extinguish arcs at the

page_text: contacts of a switch cylinder, a plurality of coils respectively connected between-
contacts near the ends of the switch cylinder.
27. As a means of providing a magnetic field adapted to extinguish arcs at the
contacts of a switch cylinder, a shaft composed of two pieces of iron divided by a
piece of non-magnetic metal, and a plurality of coils connected between the-
contacts on the switch cylinder.
28. As a means of providing a magnetic field adapted to extinguish arcs at the
contacts of a switch cylinder, a shaft consisting of two pieces of iron united by a
piece of non-magnetic metal, and a coil connected between the contacts of the
switch cylinder adapted to magnetize the shaft, thus forming a magnet adapted to.
extinguish any are that may be formed.
29. As a means of forming a magnetic field adapted to extinguish arcs at the
contacts of a switching mechanism, a magnetic circuit of iron or steel interrupted.
by a piece of non-magnetic metal, and a coil energizing such circuit.
30. In an electric braking mechanism, the combination of two electric motors,
separate retarding means for the wheels operated by the motors and means for
cutting out either one of the motors while still maintaining the operativeness of
the retarding means for the wheels.
31. In combination, in an electric braking mechanism, a plurality of braking
magnets and two electric motors with cut-out switches adapted to cut out either
one of the motors and leave all of the brake magnets in circuit with the other
motor.
32. In an electric biaking mechanism, a plurality of electric motors and a
plurality of brake magnets; in combination with cut-out switches adapted to
remove a part of the motors from the circuit, leaving the rest of the motors in-
circuit with the brake-magnets.
33. In an electric braking mechanism, electric motors, brake-magnets, and
connections between the two; in combination with switching mechanism provided
with a frame, such frame forming part of the circuit between the motors, the-
switch, and the biake magnets.
34. In combination, a controlling switch having an off position, a brake switch
having an off position, a reversing switch having an intermediate position in which.
position only its handle is removable, and interlocking mechanism between the
three switches whereby the brake switch and controlling switch are locked in their
off positions when the reversing switch is in the position in which its handle may
be removed.
35. In a locking mechanism for an electric brake, a rotating disc fast to the
axle of the car, a brake-shoe co-operating therewith, a bar spanning the two and
having a removable lug adapted to engage the outer surface of the dise, and means
for taking up the play between the lug and the disc when the shoe and the disc are
in engagement.
36. The means for locking a braking mechanism herein set out, consisting of a
bar provided with a lug, means arranged to take up the play of the lug, and
springs adapted to restore the lug to its central position when released.
37. The means for locking a braking mechanism herein set out, consisting of a
bar provided with a lug at right angles thereto, an eccentric arranged to take up.
the play of the lug, and springs adapted to restore the lug to its central position
when released.
38. The means, herein set out, for locking two opposing surfaces together,
consisting of a bar provided with a lug at an angle thereto, an eccentric adapted
to take up the play between the bar and one of the opposing surfaces when they
are brought into contact and leaf springs attached to the bar, bearing against
suitable abutments or pins and adapted to return the bar to a central position upon
its release, substantially as described.
39. In combination, an clectric motor, a car axle geared to the motor, a disc fast
to the car axle, and a biake-shoe co-operating with the disc, the brake-shoe being
suspended upon a part of the motor.

page_text: 40. In combination, an electric motor, a car axle geared thereto, a disc fast to
the car axle, a brake-shoe co-operating with the disc, and a locking mechanism
adapted to maintain the engagement of the brake shoe and disc after the cessation
of current.
41. In combination, an electric braking apparatus, and a mechanical lock for
such apparatus controlled by the last movement only of the brake switch.
42. In combination, an electric motor, a car axle geared thereto, a disc fast to
the car axle, a brake-shoe co-operating with the disc, a controlling mechanism for
the brake, and a lock or clamp adapted to be put on by the last motion of the
controlling mechanism after the shoe and disc are in engagement.
43. In combination, a series-parallel controller, a reversing switch and a brake
switch, and interlocking mechanism preventing the simultaneous operation of any
two of the switches.
44. In an electric braking apparatus, a rotary cylindrical switch having a shaft
of magnetic material, and coils adapted to energize the shaft.
45. An interlocking mechanism for electric switches, substantially as described,
comprising a bolt, as L, registering with a notch upon one of the switches, pawls,
as 2, K2, connected to the bolt by pins and slots, and cams upon two of the
switches co-operating with the pawls, one of the cams having a projection adapted
to prevent the motion of the pawl upon the other cam when the first cam is
rotated.
· ניש
1
uay vì August 1991.
For the Applicant,
J. C. CHAPMAN,
70, Chancery Lane, London, W.C., Chartered Patent Agent.