One of the most remarkable and interesting mechanical arrangements at
the Imperial Navy Yard at Kiel, Germany, is the iron clad plate bending
machine, by means of which the heavy iron clad plates are bent for the
use of arming iron clad vessels.
Through the mechanism of this remarkable machine it is possible to bend
the strongest and heaviest iron clad plates--in cold condition--so that
they can be fitted close on to the ship's hull, as it was done with the
man-of-war ships Saxonia, Bavaria, Wurtemberg, and Baden, each of which
having an iron strength of about 250 meters.
[Illustration: IMPROVED HYDRAULIC PLATE PRESS.]
One may make himself a proximate idea of the enormous power of pressure
of such a machine, if he can imagine what a strength is needed to bend
an iron plate of 250 meters thickness, in cold condition; being also 1.5
meters in width, and 5.00 meters in length, and weighing about 14,555
kilogrammes, or 14,555 tons.
The bending of the plates is done as follows: As it is shown in the
illustration, connected herewith, there are standing, well secured into
the foundation, four perpendicular pillars, made of heavy iron, all
of which are holding a heavy iron block, which by means of female nut
screws is lifted and lowered in a perpendicular direction. Beneath the
iron block, between the pillars, is lying a large hollow cylinder in
which the press piston moves up and down in a perpendicular direction.
These movements are caused by a small machine, or, better, press
pump--not noticeable in the illustration--which presses water from
a reservoir through a narrow pipe into the large hollow cylinder,
preventing at the same time the escape or return of the water so forced
in. The hollow cylinder up to the press piston is now filled with water,
so remains no other way for the piston as to move on to the top. The
iron clad plate ready to undergo the bending process is lying between
press piston and iron block; under the latter preparations are already
made for the purpose of giving the iron clad plate such a form as it
will receive through the bending process. After this the press piston
will, with the greatest force, steadily but slowly move upward, until
the iron clad plate has received its intended bending.
Lately the hydraulic presses are often used as winding machines, that
is, they are used as an arrangement to lift heavy loads up on elevated
points.
The essential contrivance of a hydraulic press is as follows:
One thinks of a powerful piston, which, through, human, steam, or water
power, is set in a moving up-and-down motion. Through the ascent of the
piston, is by means of a drawing pipe, ending into a sieve, the water
absorbed out of a reservoir, and by the lowering of the piston water is
driven out of a cylinder by means of a narrow pipe (communication pipe)
into a second cylinder, which raises a larger piston, the so-called
press piston. (See illustration.)
One on top opening drawing valve, on the top end of the drawing pipe
prevents the return of the water by the going down of the piston; and a
barring valve, which is lifted by the lowering of the piston, obstructs
the return of the water by the ascent of the piston, while the drawing
valve is lifted by means of water absorbed by the small drawing
pipe.--_Illustrirte Zeitung_.
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