Apparatus for Automatically Limiting the Speed of Electric Cars.
Year: 1895

page_text: Date of Application, 19th Mar., 1895-Accepted, 20th Apr., 1895
COMPLETE SPECIFICATION.
Apparatus for Automatically Limiting the Speed of Electric Cars.
I, Louis S. WRIGHT, residing at 1804 Wallace Street, in the City of
Philadelphia, State of Pennsylvania, United States of America, Mechanical
Engineer, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
The primary object of my invention is to afford means whereby when the
running speed of an electric car attains a predetermined limit, the brakes shall be
applied and the current simultaneously cut off, or diminished, so as to arrest, or
slow down, the movement of the car, and require the attention of the motor-man to
re-establish the normal running.
Secondary objects of the invention relate to the convenient combination of the
necessary mechanism with car of ordinary build, and to details which enhance the
proper working of the apparatus.
In the accompanying drawings I have shown a preferred type of the apparatus
as applied to an ordinary trolley car.
In said drawings, Fig. 1 represents a top or plan view of the car truck and
subjacent parts comprising my invention, the body of the car being removed.
Fig. 2 is a vertical longitudinal section, upon the line, 2, 2, of Fig. 1.
Fig. 3 is a top or plan view, on an enlarged scale, of the main group of the
devices by which the control above referred to is effected, the top of the casing
which contains said group being removed and the vertical shafts being represented
in transverse section.
Fig. 4 is a vertical central section through the governor proper, and adjacent
parts, on the line 4, 4, of Fig. 3.
Fig. 5 is a vertical section on the line 5, 5, of Fig. 3.
Fig. 6 is a central longitudinal section, on a still further enlarged scale, through
the clutch by which the governing mechanism is thrown into or out of engagement
with the direct actuating mechanism of the brakes and current controlling
devices.
Fig. 7 is a horizontal section through a portion of the current controlling device,
on the line 7, 7, of Fig. 2; and Fig. 8 is a correspondingly enlarged vertical
section through the same parts, on the line 8, 8, of Fig. 1.
Fig. 9 is a detail view of certain parts shown in Fig. 8.
Referring to the general views of Figs. 1 and 2, A indicates the base-frame of
the car, having at each end the usual projecting supports for the platform, whose
construction is well understood. The wheels of the cars are indicated at A', and
the axles thereof at A2. At each end of the car I have indicated at a³, an ordinary
form of electric switch and resistance apparatus, generally called the "controller,"
whereby the motor-man is enabled, by turning a vertical shaft, to throw the current
on to the motor with varying degrees of intensity, or cut it off entirely. The
details of this device, being well known in the art, need not be described, as it is
only important for the present purpose to state that the control is effected by
means of a rotatable vertical shaft, a, having a hand lever, a', and extending
downwards through a cylindrical casing, a³, mounted upon the platform. It is
characteristic of this class of controlling devices now generally used, that the hand
lever and its shaft, a, are rotatable through substantially seven-eighths of a

page_text: complete circle, the remaining segment, of say 45 degrees, being a blank or idle
space through which the handle does not travel. The significance of this idle
segment will be hereafter noted.
For convenience of nomenclature, I shall hereafter designate the group of
mechanism (whether of the type just indicated or any generally similar type) as
the "controller system," and "the direct actuating member of such group (in this
instance the shaft, a,) as the "prime mover " thereof.
The car wheels, A', are provided with the usual brake system, capable of
actuation from the front or rear platform, and comprising hand-levers, A', connected
by chains, A', with lever arms, A6, which are in turn operatively connected with
the movable frames, A'. Said frames are adapted to force the brake-shoes, A³,
upon the periphery of the wheels, A', against the tension of springs, (not shown.)
so that when the hand-levers are released by the brake man, the shoes are
automatically thrown clear of the wheels. It is not necessary for the purpose of
my invention to describe these devices in detail, as they are in common use, the
only important feature thereof in this connection being found in the fact that a
lever, or other moving member, is operatively connected with the brake-frames in
such manner that its positive movement in one direction shall put on the brakes,
and the release thereof shall permit the brake-springs above mentioned to throw
off the brakes and reshift the said lever to its ordinary position. The lever
referred to is indicated by the letter, A, a pair of these levers being of course
ordinarily applied, so as to permit direct control of the brakes from each end of
the car.
I shall hereafter designate the group of mechanism, whereby the brakes are
thus applied and automatically thrown off when released, as the "brake-system "
and the lever, A, or other moving member, which directly actuates the brake-
frame, as the "prime-mover" thereof.
I will now proceed to describe the group of mechanism by which, in my
invention, an automatic command of both the brake-system and controller-system
is attained.
Upon one of the car-axles, A2, is a sprocket wheel, B, which communicates by
means of a chain belt, B', with a second sprocket wheel, B2, upon the end of a
horizontal shaft, B³, having a bearing in a laterally projecting bracket, B*, mounted
upon one side of the casing, B, which encloses the main group of devices now
about to be described. Said casing, B³, may be conveniently supported upon the
under side of the base frame, A, near one end thereof, sufficient space being usually
found between the axle and the platform. The shaft, B³, extends inwards through
the casing, B, and is provided with an interior bearing, B. (See Fig. 3.) Said
shaft projects through said bearing and terminates in a bevel gear, B', which
engages (see Fig. 4) with a corresponding gear, B, mounted at the end of a
vertical hollow shaft, C. The shaft, C, (which is the governor shaft) has an
upper bearing at B³, in the top of the casing, B, and has a lower bearing in a rib
which is integral with the bottom of the casing, said portion of the bottom being,
however, dished inwards or raised above the general plane of the bottom portion
of said box, as indicated in the sectional view of Fig. 4. After passing through
said bearing, the shaft, C, projects below the bottom of the casing, B, into a
depending circular casing, Ci, which contains the governor.
1 have shown a preferred type of centrifugal governor in connection with the
apparatus, but of course do not limit myself thereto. Said governor consists of
the bails, C, carried by the jointed arms, C3, C4; the upper arms, C³, being
hinged to a collar, c, rigidly mounted upon the shaft, C, whilst the lower arms, C,
are hinged to a collar, c, rigidly attached to a vertically movable rod, c², which is
adapted to slide longitudinally within the hollow shaft, C. This group of devices,
being well known in connection with centrifugal governors, need not be more
particularly described.
At the upper end of the sliding rod, e, is a radially projecting lug, e, which
extends outwards through a longitudinal slot, d, formed through the side of he

page_text: hollow shaft, C, the length of said slot being such as to permit the longitudinal
movement of the rod and lug with reference to said shaft. Said lug projects
through the slot, d, and beyond the periphery of the shaft, C, to an extent
sufficient to engage with a collar, D, mounted upon the exterior of the shaft, C.
This collar is permitted to slide longitudinally, but is locked against rotation with
reference to the shaft, C, by means of a spline or feather, and carries upon its
exterior periphery a cam, D', which is shown in plan view in Fig. 3.
It will be seen that by reason of the play which the lug, c³, has in the slot, d,
the collar, D, and its cam, D', can be shifted from one horizontal plane to another
and that such movement is obtained by the longitudinal thrust of the shaft, c², in
correspondence with the action of the centrifugal governor. At a horizontal
plane which is within the range of movement of the cam, D', though out of its
normal plane of rotation, I mount a horizontal lever, E, which has its fulcrum
at E', and which is connected by means of the pivoted rod, E2, with one arm, E³,
of a double bell-crank lever, whose other arms are indicated at E', E', said bell-
crank having its fulcrum at E. The outer end of the arm, E, is bifurcated, as
indicated at e, to embrace a stud, e', which is mounted in the shifting member, F,
of a clutch coupling, the correlative or non-shifting member being shown at F¹.
This clutch may be of any of the well known types, but I have indicated the two
members as capable of engagement by means of opposing studs, f,f. The shifting
member, F, of the clutch, slides longitudinally upon the shaft, G, which has
bearings, G1, G2, mounted upon the bottom of the casing, B. Said shaft carries
at one end a gear, H, rigidly mounted thereon, and at the other end (adjacent to
the coupling) a freely mounted pinion, H. The pinion, H', is frictionally connected
with the non-shifting member, F, of the coupling, by means of the device
illustrated on an enlarged scale in Fig. 6. The shaft, G, is preferably surrounded
by a bushing, g, upon which fits snugly a sleeve, g', with which the non-shifting
member, F1, of the coupling is integral. The outwardly projecting end of said
sleeve, g', is threaded as indicated at g². The pinion, H', is freely mounted upon
the exterior of said sleeve, g', and the sides of the pinion are provided with annular
recesses which contain bands of frictional material, such as vulcanized fiber, indicated
at h, h. The friction band, h, is in direct contact with an annular projecting face
upon the inner side of the non shifting member, F1, of the coupling. The other
friction band, h, is in contact with the projection upon the inner face of a ring, 2,
which fits snugly upon the sleeve, g, being keyed thereto as indicated at h³.
Beyond said ring, 2, and upon the threaded portion, 2, of the sleeve, g', are jam
nuts, , o, by means of which the friction bands, h, ', may be clamped with any
desired degree of compression against the side of the pinion, H', and set, so that
sid pinion shall engage with the sleeve, g¹, with a predetermined frictional bold, and
ball slip when such hold is exceeded.
It will thus be seen that by the shifting of the clutch in correspondence with
the movement of the bell-crank arm, E, frictional engagement between the
shaft, G, and pinion, H', can be effected, the limit of such engagement however,
being determined by friction, and not being absolutely positive. The pinion, H',
meshes with two gears, H3, H4, one of said gears, H³, being the direct actuating
device for the prime-mover of the brake-system, and the other of said gears, H³,
being the direct actuating device of the prime-mover of the controller-system.
I will now proceed to describe the operation of such actuating device upon the
former of these systems.
The gear, H, is mounted upon the shaft, H, which has its bearings at H, H7.
The shaft, H, carries at its end a pinion, I, which engages with a gear, I', turning
upon a stud, 1, which is mounted upon the inner face of the casing, B. Said
gear, 1', is provided with a wrist-pin, 13, to which is pivoted a connecting rod, 1*,
attached to the lever, 1. Said lever is bifurcated at its outer end and embraces
the rod, 1', which is attached to the prime-mover of the brake-system, to wit: the
brake-lever, A, in such manner that the shifting of the lever, 18, shall, by pulling
up the rod, 17, throw on the brake. The position of the rod, I, with reference to

page_text: the rod, I', may be adjusted by means of the jam nuts, 18. Upon the side of the
gear, 11, directly opposite to the wrist-pin, 13, is a lug, I, which is adapted to bring
up against a stop, 1º, upon the casing and arrest rotation of the gear, I¹, when this
point is reached.
It will thus be seen that when engagement of the clutch couplings, F, F¹, before
referred to, brings the rotating shaft, G, into operative connection with the
pinion, H', the rotation of said pinion will, (through the gear, H³, pinion, I, and
gear, 1) actuate the connecting rod, I, and lever, 15, and shift the brake
Jever, A
The operation of the actuating device upon the prime-mover of the controller-
system is as follows:
The gear, H, which is actuated from the pinion, H¹, is mounted upon a shaft, J,
having bearings, J, on the bottom of the box, B. Said shaft, J, carries a drum, J2,
to which are connected flexible cords, K, K¹, preferably of small wire rope, which
are adapted to be wound upon the exterior periphery of the drum by its rotation.
Said cords lead to the controller at either end of the car, and as the arrangement
is similar at the respective ends, only one thereof will be described.
Referring to Fig. 8, the cord, K, is seen to be attached to a small drum, L, which
is igidly mounted upon the end of a shaft, L', arranged beneath and in line with
the shaft, a, (which is the prime-mover) of the controller. The shaft, L', has its
bearings in a cylindrical standard, L2, whose upper face is a depression, L³, which
is adapted to contain a rotatable collar, L', keyed to the shaft, LA, and carrying an
upwardly projecting lug, L. The controller shaft, a, extends down into but runs
freely within said collar, L, and is provided with a rigidly attached collar, M,
which has a downwardly depending stud, m, arranged in operative relation to the
lug, L, so that rotation of the collar, L, will by engagement between the two
lugs, rotate the collar, M, and shaft, a, through an are not exceeding seven-eighths
of a circle.
This rotation is of course effected by the winding of the cord, K, upon the
drum, J, and corresponding unwinding thereof upon the small drum, L.
A spring, L, attached to and coiled upon the shaft, L, and also attached to the
standard, I, normally tends to rewind the cord, K, upon the drum, L, whenever
the drum, J, is rotated to unwind the cord, K, therefrom. The normal position of
the lug, L', is in the idle segment of rotation of the controller shaft, a, and no
matter where the lug, m. (which is connected with the controller shaft) may be, the
lug, L, will pick up and carry it towards a position which corresponds with zero
of the current.
The general operation of the apparatus is as follows:
The governor being properly adjusted for a given rate of rotation, the cam, D',
which is under the direct control thereof, revolves in a plane or planes below that
of the lever, E, during what may be called the normal rate of speed of the car.
This position of the parts is shown in Figs. 3 and 4. As soon however as the
normal limit of speed is exceeded the balls of the governor, by flying outwards,
actuate the rod, ², and raise the cam, D', into a plane of rotation where it engages
with the lever, E, and immediately shifts said lever, so as to throw the clutch
coupling, F, F, into engagement. Thereupon the shaft, G, (which has been of
course constantly though idly rotating) becomes operatively connected with the
pinion, H, and actuates on the one hand the gear, H³, and on the other hand the
gear, H. The former of these gears, H³, through the pinion, I, gear, I, rod, I*,
and lever, 1, pulls upon the rod, 17, and shifts the brake lever, A, towards the
left in Fig. 5, thus putting on the brakes. The latter gear, H, winds up the
cords, K, K, upon the drum, J2, and through the action of the drum, L, and
rotating stud, Lo, turns the controller-shaft back towards the zero, thus simul-
taneously shutting off the electric current.
As soon as the brake-shoes, A³, bring up hard against the surface of the
wheels, A', the frictional engagement between the sleeve, g', and pinion, H', is
overcome and said pinion slips upon the sleeve. Should this result fail to occur,

page_text: however, the lug, 1º, will bring up against the stop, I³, and act as a positive check
to further movement.
The car of course stops or slows down, and the balls of the governor fall inwards,
thus retracting the cam, D', from the plane of engagement with the lever, E.
Upon the return of the cam, D', to its normal plane, it strikes against the other
arm, E, of the bell-crank, which is in a plane below that of the lever, E, (as
shown in Fig. 4) and throws it radially outwards, thus retracting the shifting
member, F, of the clutch coupling from engagement with the non-shifting
member, F, thereof, so that the pinion, H', ceases to be operatively connected
with the shaft, G. The brakes are thereupon released and their automatic
retracting spring, before referred to, throws the shoes away from the wheels. This
movement shifts the brake lever, A, back to its former position, and by so doing
reverses the movement of the groups of actuating devices, both of the brake-
system and controller-system, as follows:
The brake lever, A., pulls upon the rod, 17, and through the lever, I³, pulls upon
the rod, I, thus reversing the revolution of the gear, I', and returning it to the
initial position, shown in Fig. 5. The stop, 18, prevents the gear, I', from getting
upon a dead centre with relation to the pull of the rod, I, so that the efficient
action of the returning mechanism is ensured.
The same reverse movement of the gear, I', actuates the drum, J, in the
direction proper to unwind the cords, K, K', therefrom, and thereupon the spring
actuated drums, L, rewind the cords upon their periphery.
Figs. 10, 11 and 12 represent a modification of the apparatus intended for use in
connection with the structure where the prime-mover of the controller is a
reciprocating lever instead of a rotating shaft.
Fig. 10 is a front elevation of the controller box and its lever, showing the
platform in vertical section and the casing of the intermediately subjacent
mechanism for shifting the controller lever in side elevation.
Fig. 11 is a vertical central section through said casing, and Fig. 12 is a
horizontal section through the same on the line 12, 12, of Fig. 11, looking in the
direction of the arrows.
R indicates the controller box, and r the hand lever thereof, by the shifting of
which the current is turned on and off, or modified. Said lever is prolonged down
below the level of the car platform, R¹, through a slot, R², to the end of a
horizontally movable rod, R₁. Said rod slides horizontally in a way formed
through the bottom of the casing, S, which casing is rectangular in form, as
indicated in Fig. 12, and is divided into upper and lower compartments, as shown
in Fig. 11, by means of the partition, s.
In the upper portion of the casing, and above said partition, a disc, T, is mounted
upon the shaft, t, which rotates therewith, a spring, t, being coiled about said
shaft and connected respectively with the disc and the casing, as shown. The
shaft, t, extends down below the partition, s, and carries a rigidly attached disc, t',
having a wrist-pin, T, extending downwards and engaging in a slotted arm, T³,
which is rigidly connected to or made integral with the sliding rod, R', so that
rotation of the disc, T¹, will cause longitudinal reciprocation of said rod. A
cord, K², entering through a slot, ¹, in the upper portion of the casing, S, is
attached to the periphery of the disc, T, said cord being the counterpart of the
cord, K, before described, by means of which the controller shaft is rotated in
the first described type of my invention.
Assuming said cord to be connected with the actuating mechanism under the
command of the governor, in a similar manner to that previously described, it will
be seen that the reciprocation of the controller shaft will be effected and the
current shut off or diminished at substantially the same time as the brakes were
applied, the result of the whole operation being analogous to that previously
described.
The foregoing are typical embodiments of my invention, but I wish it to be
understood that I do not limit myself to the specific construction of parts indicated

page_text: in the various groups of mechanism which constitute the main operative element,
as it is obviously within the range of ordinary mechanical skill to vary, for instance,
the form of the governor, or of the mechanism which actuates the prime-movers
of the brake and controller systems, or of the engaging devices by which the
governor is enabled to command said actuating mechanism, as well as other
subordinate features.
Amongst the conditions, which are important in electric locomotive devices,
is the fact that if the brakes are applied, without shutting off or reducing the
current which is operative upon the motor system, there is great danger of burning
out the armatures, or other parts of the motor. To this end, the automatic command
of the brake-system should be so related to that of the controller-system, that the
putting on of the brake shall be attended by a reduction or shutting off of the
current of the motor, in so far as the same tends to run the car against the holding
action of the brakes. Whilst, therefore, the current might without danger be shut
off before the brakes are applied, I believe it to be highly desirable that the
converse of this should be provided against, and that the application of the brakes
should be either simultaneous with, or not substantially precede, the cessation or
diminution of the current.
It is also desirable that there should be at some point in the train of mechanism,
between the brake and controller system, on the one hand, and the primary source
of power, for the actuating mechanism thereof, on the other, a point where a
frictional engagement, instead of a positive one, is employed. Otherwise, unless
the action of the devices is very carefully regulated, or the parts provided with
some form of compensation, there might be danger of injury should the car fail to
stop when the practical limit of tension of the brakes, or of movement of the
controller mechanism had been attained. I have thought it best to locate this
point of frictional engagement at or near the clutch which is controlled by the
governor, but obviously it would operate in the same manner if located at any
point between the primary source of power, (in this instance the car axle,) and
the ultimate members of the systems which it is intended to actuate. Hence I do
not limit myself to the exact location above specified for this frictional engaging
device.
In cases where the prime-mover of the brake-system is an absolutely separate
device from the prime-mover of the controller-system, the intervention, between the
primary source of power and these local prime-movers, of two groups of actuating
mechanism, one directly operative upon each system, is the most obvious and
believe the most practicable embodiment of my invention; but at the same time
such subdivision into two groups is not essential.
Thus when the prime-mover of the brake-system and of the controller-system are
inter-connected, as, for instance, in the device shown in United States Letters
Patent No. 525,336, dated September 4th, 1894, or in any case where the movement
of a common member is operative upon both the controller system and the brake
system, a single group of actuating mechanism commanded by the governor and
operatively connected with the common member, would be sufficient for the purposes
of my invention.
When, however, an electric brake system is employed, (such for instance as that
shown in United States Letters Patent No. 330,605, dated November 17th, 1885,)
and the same local prime-mover which shuts off or diminishes the current, utilized
to turn on the current of the brake system, it is equally obvious that the employment
of two groups of intermediate actuating mechanism, between the governor and such
local prime mover, would be superfluous. Hence when in my claims I use the term
actuating mechanism as comprehending the devices intermediate (in the train of
mechanical operations) between the primary source of power and the local prime-
mover or prime-movers aforesaid, I do not imply that a plurality of groups of such
intermediate actuating mechanism is essential, but mean to include such actuating
mechanism, whether it be arranged in separate groups individually connected with
said local prime-movers, or in a single group, common to both.

page_text: I use the term electric car as comprehending generally any electrically actuated
locomotive vehicle.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is,
1. In an electric car, comprising a motor, a controller-system and a brake-system
the combination of a governor; means substantially as set forth for driving the
same in conformity with the speed of movement of the car; actuating mechanism
substantially as set forth; a primary source of power for driving said actuating
mechanism; and an engaging device operated by the governor and commanding
the connection between the primary source of power for said actuating mechanism,
and the controller and brake systems, substantially as described.
2. In an electric car, comprising a motor, a controller system and a brake-system,
the combination of a governor ; means substantially as set forth for driving the
same in conformity with the speed of movement of the car; actuating mechanism,
substantially as set forth, operatively connected with the brake and controller
systems; means, substantially as set forth, for driving said actuating mechanism
from the running of the car; an engaging device, operated by the governor, and
commanding the connection between the primary source of power for said actuating
mechanism and the controller and brake systems; and a frictional connection
located in the train of mechanism between said primary source of power and the
controller and brake systems, as and for the purposes specified.
Dated this 19th day of March 1895.
CARPMAEL & Co.,
Agents for the Applicant.