The illustration represents a multiple wire tester, constructed for the
Trenton Iron and Steel Company by Riehle Bros., of Philadelphia. It
consists of a weighing mechanism (seen on the left, with a capacity of
4,000 pounds), two single or alternating pumps, a hydraulic jack, a
patented three-way valve, and a rising and falling accumulator.
The weighing end of the machine, placed horizontally and secured by
bolts to a foundation, is accurate, and will weigh the strain on one to
six wires at a time. It is provided with self-adjusting grips to take
in wires from No. 10 to No. 16, and hold them firmly. It can be adapted
to take in a larger or smaller range of numbers when desired. There is
a set of gripping appliances at both ends, and in the present instance
they are 90 feet apart--one set at the scale end, and the other secured
to head of piston. The jack is 5 feet in length, and lined with brass;
its outside diameter is 3½ inches; its inside diameter, 2¼ inches. Like
the scale end, it is firmly bolted down to its foundations.
The plunger has a stroke of 4 feet. It is supported and guided by three
guides, the top one being a straight tube running on turned rollers. A
three-way valve controls the movements of the jack and accumulator, and
supplies water to the jack by a lever. When the lever is raised, the
water is forced into the larger area of the jack, causing the plunger
to move backward and bring a strain on to the wires or other specimens;
when the lever is lowered, the water in the larger area of the jack
only returns to the reservoir of the pump (to be used again). Now,
without changing the position of the lever, the plunger will return
automatically, without weight or counterbalance, with a steady, smooth,
and uniform motion.
The pump has a slow motion, 60 revolutions per minute. It has two
single action pistons, and the valves are so simple and readily
accessible that an ordinary mechanic can examine and repair, when
necessary, in a short time. The accumulator is so arranged as to
overflow when it comes to its maximum height. The machine can be
adapted to stretching and straightening wires in lengths to a given
amount.
The weight on the scale and that on the accumulator is made to
correspond, so that wires of a certain number or size can be quickly
tested in quantities under exactly the same conditions, with only the
movement of the lever.
[Illustration: IMPROVED WIRE TESTING MACHINE.]