Hydraulic Machine Tools. Probably in no department of engineering has the use of hydraulic power met with more success than in its application to certain machine tools. This success is owing to the peculiar suitability of pressure—water as the motive agent for the performance of a certain class of operations requiring the exertion of a great force with comparative slow motion, as in punching, riveting, forging and the like.
The wide spread and successful use of hydraulic machines—of which a few only have been described and illustrated upon the pages of this book—is due to the necessity for such tools and the inventive ability of our tool designers.
A large fixed hydraulic riveter is shown in Fig. below; it is capable of exerting on the rivet a pressure of 40 tons or more; the machine has a working pressure of 1,500 pounds per square inch. Working pressures of 5,000 to 10,000 pounds per square inch are used in hydraulic forging presses, but in the riveter much less pressure is required.
Note.—The proportions of this machine are immense. The platform weighs 22,500 lbs. and is operated by a single lever shown in the side view. The “gap” is 8 feet across. The machine has a large steel “stake” carrying the stationary die; this is held in tension strain by the two steel bolts shown, one upon each side of the machine. The other part of the jaw is cast iron.
CLASSIFICATION
OF PUMPS
Fig. 155.—The Bellows Pump.