This machine is a large hydraulic press, with an adjustable head, and a
weighing system for recording the loading developed by a triple-plunger
pump. It has a maximum clearance of 65 ft. between heads; the clearance
in the machine is a trifle more than 6 ft. between screws, and the heads
are 6 ft. square.
The machine consists of a base containing the main cylinder, with a
sectional area of 2,000 sq. in., upon which rests the lower platform or
head, which is provided with a ball-and-socket bearing. The upper head
is adjustable over four vertical screws, 13½ in. in diameter and 72 ft.
2 in. long, by a system of gearing operating four nuts with
ball-bearings upon which the head rests. The shafting operating this
mechanism is connected with a variable-speed motor which actuates
the triple-plunger pump supplying the pressure to the main cylinder
(Fig. 4).
The weighing device consists of a set of standard Olsen levers for
weighing one-eightieth of the total load on the main cylinder. This
reduction is effected through the medium of a piston and a diaphragm.
The main cylinder has a diameter of 50 in., and the smaller one, a
diameter of 5-9/16 in. The weighing beam is balanced by an
automatically-operated poise weight, and is provided with a device for
applying successive counterweights of 1,000,000 lb. each. Each division
on the dial is equivalent to a 100-lb. load, and smaller subdivisions
are made possible by an additional needle-beam.
The power is applied by a 15-h.p., 220-volt, variable-speed motor
operating a triple-plunger pump, the gearing operating the upper head
being driven by the same motor. The extreme length of the main screws
necessitates splicing, which is accomplished as follows:
In the center of the screws, at the splice, is a 3-in. threaded pin for
centering the upper and lower screws; this splice is strengthened by
sleeve nuts, split to facilitate their removal whenever it is necessary
to lower the upper head; after the head has passed the splice, the
sleeve nuts are replaced.
In order to maintain a constant load, a needle-valve has been provided,
which, when the pump is operated at its lowest speed, will allow a
sufficient quantity of oil to flow into the main cylinder to equalize
whatever leakage there may be. The main cylinder has a vertical movement
of 24 in. The speed of the machine, for the purpose of adjustment, using
the gearing attached to the upper head, is 10 in. per min. The speed for
applying loads, controlled by the variable-speed motor driving the pump,
varies from a minimum of at least 1/60 in. per min. to a maximum of at
least ½ in. per min. The machine has a guaranteed accuracy of at least
one-third of 1%, for any load of more than 100,000 lb., up to its
capacity.
[Illustration: Fig. 4.
PLAN AND ELEVATION OF 10,000,000-LB. VERTICAL COMPRESSION
TESTING MACHINE]
The castings for the base and the top head weigh approximately 48,000
lb. each. Each main screw weighs more than 40,000 lb., the lower
platform weighing about 25,000 lb., and the main cylinder, 16,000 lb.
The top of the machine will be about 70 ft. above the top of the floor,
and the concrete foundation, upon which it rests, is about 8 ft. below
the floor line.
[Illustration: PLATE XIV.