IMPROVEMENTS IN AUTOMATIC BRAKES FOR TRAMWAY CARS AND OTHER VEHICLES
Year: 1883

page_text: LETTERS PATENT to Edward Bellingham Price, of Portrush in the County of
Antrim, Ireland for an Invention of IMPROVEMENTS IN AUTOMATIC BRAKES FOR
TRAMWAY CARS AND OTHER VEHICLES
PROVISIONAL SPECIFICATION left by the said Edward Bellingham Price
at the Office of the Commissioners of Patents on the 2nd August 1883.
EDWARD BELLINGHAM PRICE of Portrush in the county of Antrim, Ireland
"IMPROVEMENTS IN AUTOMATIC BRAKES FOR TRAMWAY CARS AND OTHER
VEHICLES
"
My Invention relates to a self acting brake for tramway cars and other vehicles,
and consists in the use of a centrifugal governor and of a friction clutch to which
the brake blocks are connected, the said governor and clutch being so arranged
that the brake blocks which are held free of the wheels while the vehicle is
travelling at the proper speed will be automatically applied immediately an
excessive speed is attained
The governor may consist of a double lever or arm inclined at an angle to the axle
of the vehicle and turning on an axis attached thereto. The lever carries weights
at its extremities which, while the vehicle is travelling at its ordinary speed lie
close to the axle, and has a crank to which is connected a horizontal sliding rod
adapted to act on the clutch mechanism. The clutch, which is mounted on the
axle at the opposite end, may be of any suitable kind, but it would preferably
consist of a modification of the clutch known as Addyman's wherein a split ring
is expanded within a shell or box by means of a wedge. The brake chains may
be attached to the shell or box which is free to turn loosely on the axle and so
constructed that the chains will coil thereon and the horizontal rod which is held
in bearings on the axle passes through that portion of the clutch which is keyed
to the axle and terminates in a wedge adapted to expand the split ring and bring
the clutch into action. The horizontal rod may be furnished with a spring for

page_text: retracting the wedge when the speed slackens, and with means for regulating the
tension of the spring according to the limit of speed desired.
The operation is as follows:-When the vehicle is travelling at the proper speed,
the weighted lever lies close to the axle and the wedge being withdrawn, that
portion of the clutch to which the brake chains are attached is loose in the axle.
As soon however as there is any acceleration in the speed beyond the proper limit,
the centrifugal force causes the weighted lever to assume a more vertical position,
thereby forcing the horizontal rod in against the spring which it compresses, and
bringing the clutch mechanism into operation applies the brakes,
The clutch would preferably be made in halves bolted together in order that the 1
apparatus may be fitted to the vehicle without removing the wheels.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Bellingham Price in the Patent Office on the 2nd February
1884.
EDWARD BELLINGHAM PRICE of Portrush in the County of Antrim Ireland.
"IMPROVEMENTS IN AUTOMATIC BRAKES FOR TRAMWAY CARS AND OTHER
VEHICLES
"
My Invention relates to a self acting brake for tramway cars and other vehicles
and consists of a centrifugal governor and friction clutch so combined and
arranged in connection with the brake blocks as to remain inoperative whilst tho
vehicle is travelling at the proper speed but to be brought into operation by
centrifugal action and cause the brakes to be automatically applied to the wheels
immediately an excessive speed is attained.
In order that the invention may be more readily understood I have illustrated
it in the accompanying Drawings and will proceed to describe it with reference
thereto.
Figure 1 is an elevation of one form of combined centrifugal governor and
clutch for automatically operating the brakes. Figure 2 is an elevation partly in
section of a modified form of clutch, the governor remaining the same. Figuro 3
is a diametrical section, and Figure 4 is a cross section on line 1-1 Figure 3 of a
combined centrifugal governor and clutch.
"
In Figure 1 the governor consists of a weighted lever A pivoted at a. to a clamp
fixed on the wheel axle so as to be carried round therewith. The clutch shown in
this figure and in cross section in Figure 5 is of the kind known as "Addymans
friction clutch. It is composed of the parts B. B¹. C and D. The part B is a shell
or box loose on the axle and the part B¹ is a plate keyed on the axle. O. C. aro
a pair of levers fulcrummed between the ends of a split friction friction ring D
which is caused to expand and fit tightly in the shell B by a wedge e. inserted
between the opposite ends of the levers O. The friction ring D is connected to the
plate B¹ by the part b thereon engaging with the friction ring D as shown. The
wedge e. is on the end of a rod E capable of sliding longitudinally in a guide in
the part B and in a bearing E¹ clamped on the wheel axle. This rod E is
connected by a link F with a crank pin f fixed on the governor lever A whereby
when the latter is caused by the centrifugal action of its weighted ends when
revolving at an excessive speed to approach a position at right angles to the axis
of the wheel axle, the wedge e will be driven forwards and so cause the friction
ring D to grip the shell B so that the two parts B. B¹ of the friction clutch will
revolve together.
The part B has a drum B' attached to it, to which is connected a chain fastened
by its other end to the lever of the ordinary brake gear which chain is wound up
by the revolution of the part B. B. and causes the brakes to be applied. Except
when travelling at an excessive speed the wedge is retracted and the governor
lever is caused to lie alongside the axle by the stress of a spiral spring G upon
rod E confined between the part B' and locknuts screwing on a threaded part of
rod E by adjusting which the stress of the spring which must be overcome by the
centrifugal action of the governor before the clutch mechanism can come into
action, may be varied according to the speed of the vehicle at which it is required
the brakes should be automatically applied.
In Figure 2 the clutch is in the form of a double friction cone of which the male
cone C is connected to the axle by a key and groove so as to turn therewith whilst
freo to slide thercon and the other male cone C¹, is fast on the axle or on the wheel

page_text: boss. The drum composed of the two female cones or wheels B. B¹. is loose on the
axle and is connected by a chain with the brakes as before. The cone C is
connected by a pair of rods E with a moveable cross head E¹ to which the link F
is pivoted, the rods E sliding through guides in another cross head E fast on the
axle. G are spiral springs upon rods E confined between the fixed crosshead E and
adjustable collars on the rods whereby to draw the cone C back and cause the
governor lever to lie alongside the axle at normal speeds. The governor lever A
has a crank pin f to which link F is connected as before, the action being the
same as before described.
I have shown a double cone clutch but I would observe that a single cone C and
the corresponding part B may alone be employed if preferred-or any other friction
clutch or arrangement.
In Figures 3 and 4 the weighted lever A is dispensed with and the clutch is
composed of a shell or drum B running loose on the axle and a disc C keyed on
the axle and of centrifugal friction dogs A carried round with disc C and fitted
to slide radially between guide studs c. carried by said disc. The head of each
centrifugal friction dog is curved on the external face to correspond to the internal
periphery of the rim of drum B against which it presses and its shank a. is slotted
to receive an abutment stud d and a spiral spring D confined between said stud
and a head e, on a screw stem received in a tapped hole in the end of the shank a..
and adjustable for the purpose of regulating the stress of the spring according to
the speed at which it is desired the brakes should come in operation: The
drum B is in ono with a barrel upon which is coiled a chain connected to the brake
gear as before.
The springs retract the friction dogs and hold them out of contact with the
drum B until their centrifugal force overcomes the springs and causes them to
grip and turn the drum thereby applying the brakes.
In all the above described arrangements the pull of the chain may either directly
draw on the brakes of the tramcar or of the engine or of all the cars of a train or
it may be connected to and operato a steain valve controlling a steam brake on the
engine and the reversing gear whereby the engine is reversed when the speed
becomes excessive and the brakes applied.
Having described the nature of the said Invention and the manner of performing
the same I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is :-
First. The combination of centrifugal and friction clutch mechanism applied to
the wheel axle of a car for operation substantially in the manner herein described
for the purpose specified.
Second. The respective combinations and arrangements of the combined
centrifugal and friction clutch mechanism substantially as herein described and
shown in the respective figures of the Drawings for the purpose specified.
In witness whereof I the said Edward Bellingham Price have hereunto set my.
hand and seal this thirty-first day of January in the year of our Lord One
thousand eight hundred and eighty four.
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