Evening star. [volume] (Washington, D.C.) 1854-1972, 1899-01-14

his business compels him to do this, because
the result is financial embarrassment to
him If his elevators drop occasionally. This
applies with equal force to owners of build
ings, who would have difficulty in securing
tenants II the elevator apparatus were sus-
pected of being dangerous, Many even go
beyond the purely mechanical device and
introduce a pneumatic arrangement as
last resort only to be brought into action
when all else fails. ~
The air cushion. located a9fthe bottom of
an elevator shaft possesses peculiar in
herent advantages which cannot be gain
said. First, and most essential, 1t is always
ready to perform it's work instantly, and to
do it successfully, under an conditions. OF
itself it cannot get out of order, since,
practically, it is only hole into which
something may drop, somei time. Whether
the car dropped one or twenty stories, its
movement would cease, not suddenly, but
gradually, and without shock. The first
cost of the air cushion is small and the out
lay for its maintenance MI. 1t occupies
space not otherwise valuable. All things
considered, it is difficult to understand why
it is not more widely employed.
One of the most extensive and elaborate
applications of the elevator air cushions is
to be found in the Empire building, New
York. The building is twenty-story office
building, recently completed and provided
with all the most modern appliances and
conveniences. There are ten elevators OF
the high speed hydraulic type, arranged in
two groups of five each While nine of the
elevators are distinctly for passenger ser
vice one Is more powerful and is capable
of lifting safes weighing 5000 pounds. Each
shaft is entirely independent from the floor
of the third story to the bottom, and is In
closed by walls which are not perforated
except by the door openings. This forms
the air cushion proper, which is about fifty
feet in depth. The doors of the main floor
and of the second floor are in two parts,
which slide in recesses in the wall. These
are of bronze and of ample strength to re-
sist the air pressure that would come upon
them If a car should fall. The usual open
iron work is entirely absent on these two
floors, solid masonry replacing it. The cars
have also been strengthened with the view
or resisting this pressure. The shaft walls
are battered for short distance below the
third-story floor. The shaft at this point
is ten inches wider than the bottom, the
batter extending just below the second
floor. This provides a graduated air escape
and adaptS the cushion to any fall which
the car may make. The car fits more close
ly the lower portion of the shaft, the walls
of which are vertical. 1t has been estimat-
ed that the air cushion should be in proper
ton of l to of the travel; in the present
instance the cushion is fifty feet and the
travel 2S7 feet. In the bottom of each
shaft is a suction valve which opens in
wardly as the car ascends, thus preventing
the vacuum which would result from the
car leaving the custom. There Is also an
escape valve, which opens outwardly into
the atmosphere. 1t is SO adjusted as to
sustain the weight Of a car under ordinary
conditions, but WILL in case Of accident re-
leve the cushion of undue pressure when
the car falls. 1t has been calculated that
the pressure In the air cushion, If a car
should fall from the top, would be 49,
pounds to the square inch.
On July IS, a car weighing 1000 pounds
was dropped from the twentieth story. The
efficiency of the cushion was shown by the
fact that the eggs and incandecent lamps
carried upon the floor Of the car were I'M
injured.