Improvements in Car Brakes.
Year: 1897

page_text: Date of Application, 5th Jan., 1897-Accepted, 20th Feb., 1897
Improvements in Car Brakes.
I, JAMES CALVIN DEVLIN, of Hernando, County of De Soto, State of
Mississippi, United States of America, 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 object of the invention is to provide a brake that may replace those now
commonly used, without changing the car or trucks; that shall under all conditions
apply equal force to all the wheels; that is so arranged that the slack necessary
in rounding curves may be instantly taken up when it is desired to apply the
brake; that shall be simple, strong, very powerful, and not liable to cause vibration
of the car; and that is equally adapted for use upon street or steam cars, and to be
operated by hand or power.
Certain of these ends are attained by suspending the brake from the truck
instead of from the car itself, and so arranging it that under light force it acts
upon the wheel only while under greater stress it automatically acts upon the
rail as well as the wheel.
The brakes acting upon all the wheels are all operated from either end of the
car, and as the devices for two sets of four wheels each are precisely similar, only
one set of the duplicate parts is fully shown and described.
In the drawings forming a part of this application :
Fig. 1 is a side elevation of the brakes and brake operating devices for one truck,
the truck frame being largely omitted.
Fig. 2 is a plan view of the same devices.
Fig. 3 is a detail view of a certain rock-shaft and its arms.
Fig. 4 is a section on the line 4-4, Fig. 1.
In all the drawings where the letters occur, A, A', are car wheels resting upon a
track B, and C is a truck frame which projects beyond the wheels and supports at
each end a combined wheel and track brake D. This brake consists of a common
brake beam D' bearing at its ends cast plates Y, Y, wheel impinging brake shoes Y',
of usual form, and rail impinging brake shoes Y2 secured to the lower sides of the
plates in position to meet the rails when depressed. The truck frame has trans-
verse members and upon each of these are detachably bolted stirrups C² each
baving a horizontal member C' at some distance below the member C'and projecting
therefrom toward the wheel.
To the plates Y are pivoted rods D' which pass up through the members C³ and
have upon their threaded upper terminal portions nuts D' which rest upon springs D'
supported upon the members C. The brake is thus sustained wholly by the springs,
and the force required to carry the brake down until the shoes Y2 rest upon the rails
may be varied at will by turning the nuts D. Just within the planes of the wheels,
upon each side, are rods E, pivoted to the brake beam D' and extending toward the
middle of the truck. At a suitable point between the two brakes a transverse rock-
shaft F is mounted in steel bearings F' rigidly supported from the truck frame.
The shaft opening in these bearing blocks is a broad slot allowing the shaft no
vertical movement but permitting it to move bodily toward either brake. From
the middle portion of the rock-shaft a rigid arm F2 projects obliquely upward, and
at the end of the shatt are similarly inclined, short, rigid T-bars F³. To the lower
ends of the T-bars, respectively, are pivoted the rods coming from one brake beam

page_text: and to their upper ends the rods from the other beam are connected in like manner.
All the four rods are preferably provided with turn-buckles G, for accurately
adjusting their lengths. Beneath the middle portion of the car is a transverse
bar H, centrally pivoted to a suitable bracket H', adapted to be supported from
the body of the car. The central pivot lies in a slot H2 in the bracket and the
bar is thus allowed to move bodily toward either end of the car. From the ends
of the bar, rods I run, respectively, to brake staffs J at each end of the car. Upon
each side of the bracket a rod K is pivoted to the bar and pivotally connected at
its other end to the upper end of the corresponding rock-shaft arm, F. Each
rod K is also provided with a length adjusting turn-buckle. The rods I are con-
nected to the corresponding brake staffs by chains, but the connection is indirect.
A casting L rests like a half sleeve against the staff at some distance from its
lower end and is secured by a bolt projecting from the casting through the staff
and bearing a nut upon its free threaded end. The bolt is nearly midway between
the top and bottom of the casting so that the casting may compensate the
weakening of the staff by perforation. From the lower part of the casting
projects an arm M provided with a series of perforations M₁ to receive an
eye-bolt M2, to which the end of the rod I is connected by a chain I'.
Evidently when the arm is in line with the rod I and extending toward it; a
half revolution shortens the chain by an amount equal to twice the distance
from the eye-bolt to the axis of the staff, and this distance is greater or less
according as the eye-bolt is placed in one or another of the perforations in the
The ordinary slack found necessary upon street cars is thus taken up
by half a turn instead of by two and a half revolutions, and when it has thus
been taken up the chain winds upon the staff as usual and the usual force is
exerted.
arm.
By giving the rock-shaft the sliding bearing already described, should either of
the wheel shoes seen in Fig. 1, for example, meet its wheel in advance of the like
meeting by the other shoe, as the brake is applied, instead of the expenditure of
all the force on the one wheel, the end of the shaft slides until the other shoe also
meets its wheel and applies an equal share of the total force here exerted. At. the
opposite side of the car the result is the same, and still the same even if that end
of the rock-shaft must slide in the contrary direction. But if no other equalizing
devices are employed, it would be possible for the brake acting on these. four
wheels to operate while no force was applied to the four under the opposite end of
the car. The bar H is therefore arranged as above described, and hence it will in
case of need swing about the pivot of one of the rods K until the strain upon the
two rods, and hence upon the brakes of the two sets of trucks, is the same, or
until the force applied to each wheel is just equal to that applied to each of the
others.
Now when the brakes, arranged as stated, are applied with moderate force, all
the wheel shoes are pressed against the corresponding wheels, exerting retarding
force in the usual manner. But the friction of the wheels draws downward the
shoes which chance to be on the front side of the advancing truck, and with a
force varying with the braking force applied. When this force exceeds the
resistance of the brake supporting springs the rail shoes are pressed against the
rails. Instantly, the friction against the rails presses them more forcibly against
the wheels, beneath which they wedge, to some extent, and in turn the extra
pressure upon the wheel further increases the pressure upon the rail. In other
words, when the braking force applied is sufficient to cause the descent of the brake
shoes to the rail, the momentum of the train multiplies the braking effect until the
train stops or the initial force is discontinued,-when the springs restore the brakes
to their original positions.
As the brakes are all supported from the trucks and not from the car itself, the
application of the brake causes no vibration and the very disagreeable sense of the
grinding of the surfaces is avoided.
It is obvious that the embodiment of the invention may be varied by any

page_text: mechanic, and I do not therefore wish to limit myself to the precise constructions
set forth, but
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. The combination with a truck frame, of springs supported upon the frame, a
brake beneath the frame, supported by said springs and provided with both wheel-
impinging shoes and rail-impinging shoes, and means for swinging said brake toward
the wheels.
2. The combination with a truck frame, of vertically sliding rods carried by
said frame, springs arranged to resist downward movement of the rods, a brake
pivotally supported by the rods and provided with wheel-impinging shoes and
with rail-impinging shoes, and means for swinging the brake toward the.
wheels.
3. The combination with a four wheeled truck having brakes adapted to swing.
horizontally against the wheels, of a transverse rock-shaft mounted in bearings
adapted to permit bodily lateral movement and provided with suitable rigid arms.
near each end, rods connecting the arms at each end, respectively, to the
brakes swinging against the corresponding wheels, and means for rocking the
rock-shaft.
4. The combination with the truck having brakes arranged for pressing the
wheels, respectively, of a rock-shaft supported in bearings permitting bodily
lateral movement and provided with rigid end arms and with a rigid central
arm, devices connecting said end arms, respectively, to the corresponding
brakes, and devices connecting the free end of the central, arm to brake operating
mechanism.
5. The combination with two four-wheeled trucks each having brakes acting upon
its several wheels, of a lever centrally pivoted between the trucks and movable
toward either, two transverse rock-shafts lying, one in each truck, between the
pairs of wheels and mounted in bearings permitting either end to move toward
either pair of wheels, devices connecting the arms of said lever to the rock-shafts,.
each to each, to operate the latter, and devices connecting each end of each-rock-
shaft to the brakes acting upon the adjacent wheels.
6. The combination with two sets of trucks each provided with brakes for each.
wheel and with a transverse rock-shaft connected to the several brakes to
operate them by its rotary motion, of a lever arranged, between the sets, for
bodily movement toward either, devices connecting the lever arms, respectively,
to the corresponding rock-shafts to operate them, and means for drawing one lever
arm toward one of said sets.
Dated thio 7th day of Dreamber 1806