Tulsa daily world. [volume] (Tulsa, Indian Territory [Okla.]) 1905-1919, 1917-03-11


inch. 1t is. therefore. reasonable TO
assume that by exhaustion of the air
from the space above the piston in
the cylinder atmospheric pressure
against the other face will exert at
least 10 pounds pressure.
1000 Pounds Pressure Possible,
With its 7-inch diameter and 4-inch
stroke the piston has a displacement
of 80 square inches which, with the
lO-pouud pressure cNerted win, of
course. give direct pun OF 800
pounds. This i'm turn is compounded
thru the togele to GiN' the 1000 !
pound pressure. This is merely an
example Of the capabilities of the new
brake. as 1000 pounds would seldom
hc found necessary unless in large
trucks
y representative OF Motor Age
drove a Packard twin six ana Nclie,
the former equipped with hand OPP
Grated vacuum brake 1ud the latter
with pedal operation In ordinary
driving. thru traffic and over hilly
country roads the feasibility Of the
brake could not be questioned. The
/ Packard Wds put up to 80 miles per
hour ana b AXE lever applied with
touch of the little firger-and the
rear wheels locked, both of them. so
that the car slid i'm a straight path up
D
thrown out of adjustment, it was
aSain found possible TO lock both
wheels evenly, as the extreme pres
sure possible took up the difference
thru the cquallzers Then again,
driving at any speed II was possible
/ by shorter movement of The lever
to give the brakes the very slightest
touch so that their effect was hardly
noticeable. Any degree of pressure
! between these two was easily on
tainablC
The brake will operate with enough
force to slip the wheels as long as the
motor is turning over. As an exam
pie of this the Packard was driven
by the starting motor alone, meaning
that the ear was travelling possibly
half mile per hour. Full applica-
tion of the brake lever locked the
wheels. IT might be noted here that
the brakes on the Packard were so
set that it was necessary to throw
the entire weight on the regular
brake pedal, which was connected to
the save levers. in order to slip the
wheels. In descending steep declines
where it is possibly advisable to turn
off the ignition and leave the clutch
engaged. the brake will operate as
efficiently as it will with tho motor
under power
In the pedal operation as applied
to the Nelie, driving thru crowded
| traffic was n revelation. The pedal
was located directly beside the ac-
celerator. Thru the most crowded
traffic operation of The car was
simply q matter of oscillating the foot
from the aceelerator to the brake
pedal and vice versa, about the same
amount of foot pressure being re-
quired to operate both. The car was
driven into a deep ditch, the brake
applied with the foot. a shift made
into reverse, the foot switched from
the brake pedal to the accelerator and
the car slid out without difficulty.
There is no mechanical principle in
the device which Is new. The cylin-
der is very similar TO the ri-brake
cylinders used in braking OF railroad
/ trains. With a pressed-s steel shell and
cast-stoel head, the entire cylinder
weighs i'm the neighbOThood OF twelve
pounds. The thin steel piston en-
bodies leather plunger, similar in
deAgn to the type used in locomotive
air brake cylinders which have been
shown to give seven years service
before replacement was necessary.
The automatic valve has four main
parts. a barrel the operating lever
a piston and two springs As will be
seen by reference to the cross section
of the valve, the piston floats between
the two springs The lower spring Is
a retaining member.
BY pressure against the lever to any
given distance the large spring Is
pushed down. carrying with 1t the
piston and thus opening the valve
which permits n suction to be con-
Quoted from the intake manifold TO
the braking cylinder The pressure
in the space in which the large spring
is located equalizes with the pressure
| In the suction end Of the braklng CYL
inder, atmospheric pressure exerts It.
self against the piston In the valve,
thru the vent IN the bottom. which
causes the piston to rise against the
spring and shut off the suction from
/ the manifold, at the same time with
holding a constant amount of suction
in the braking cylinder. by releasing
the operating lever the piston rises
further so that the atmospheric pres
sure forces air thru the vent in the
| bottom of the valve, thru another
vent into the pipe leading to the op-
Grating cylinder and thus equalizes
the pressure on each side of the pis-
ton in the operating cylinder thus re-
leasing the brake.
Instant Brake Release.
The release is almost instantaneous.
so rapid in fact, that 1t is impossible
to shift the foot from the brake pedal
to the accelerator quick enough to
catch the brakes.
Tight connections are unnecessary.
AS q matter OF demonstration, a sys-
TEN was connected up with each
union turned In place with the fingers
only. To aggravate conditions n pipe
was inserted between the valve and
the manifold which was drilled thru.
Still the device worked perfectly.
The vacuum brake is the invention
os Benjamin G. Kramer, who Is now
associated with the Pres O-Idte COM
pany in It's manufacture. II will be
marketed with view of furnishing
brackets for attachment for all we'll
knnwn M Lnn "a cnrs hnth n. a q. -