The important features which distinguish this invention from other devices having a like object in view are the drawing of the metal of a rod in the direction of its axis, thereby reducing its diameter in whole or in part, instead of " upsetting " or shortening the metal and thickening por tions to a greater diameter than that of the rod, and a non-requiring of any attempt to finish the surface until the metal has been shaped in the form desired for the complete article.
The machine consists of two reciprocating tables, which slide vertically in guides simultaneously and with equal velocities, but in opposite direc tions. These tables are propelled by a train of toothed gearing, which, operated by two pulleys turning in reverse directions, engages with racks and pinions. The pulleys are alternately engaged with the gearing by a coupling or clutch actuated by a shifter participating in the motion of the gearing propelling one of the slides. One of the guides, with its sliding table, may be so adjusted as to distance from the other that the changes required by the diameter of the work may be made.
The dies, which are fixed to the inner sides of the slides, are so formed that as one descends and the other ascends the space between them dimin ishes. A heated bar of metal being placed between them is rolled, while the position of its axis is not changed. The working faces of the dies are so inclined, as to the direction of their motion, as to draw the metal length wise in the direction of the axis of the bar, whose rotation is enforced by teeth which are formed in the prominent parts of the dies, and which indent and turn the metal as two oppositely-moving racks would turn a pinion placed between them. In no part of the operation is attempted the compression or shortening of the metallic bar in the direction of its axis.
The reduction in diameter is so gradual that material of a reasonable degree of strength and homogeneousness is never severed at the centre by being flattened and by moving in opposite directions, but instead there is an extension in the direction of the axis. This effect is produced by the gradual inclination of the dies toward each other, which inclination is attended with a relatively rapid divergence of their prominences or ridges and intervening cavities. This configuration of the dies proceeds to the point where all parts of the material are reduced to the proper diameter.
In the rest of its length the ridges or working surfaces of the dies are parallel and finish or smooth the surface of the article.
Antonia/le Vending have been made in the present volume to instances of mechanical reinvenlions. A curious exam ple of a modern invention, whose prototype appears to have been known and employed before the Christian era, is the "drop-a-nickel-in-the-slot "' machine. In the sixteenth century there appeared a manuscript by Hero entitled Spirt*lalia sal Pneumaliar, which contained an exposure of the many deceptions practised by the Egyptian hierarchy. In this work is described a device for automatically dispensing to the worshippers, on their entrance to the temple, the lustral or purifying water which was a source of revenue to the Egyptian priests. Figure 5 shows, partly in section, this apparatus, whose construction and operation, according to Hero's description, were as follows: The vase-shaped vessel was entirely closed with the exception of a slit at the top for the introduction o.f the necessary coins, which were five drachma? (about seventy-five cents), and no less amount would produce a drop of the lustral water. The water was contained in a cylindrical vessel, to the bottom of which a small tube was attached and continued through the side of the vase for the discharge of the liquid. The inner end of the tube formed the seat of a valve whose plug was fixed on the lower end of a vertical rod. The upper end of the rod was connected by a pin to one end of a horizontal vibrating lever, whose other end was spread out in the form of a flat dish for the reception of the coifs dropped through the slit. The weight of the rod kept the valve closed, and no liquid could escape. When the required coins were dropped through the "slot " upon the dished end of the lever, the lever was depressed and raised the rod of the valve, which opened and permit ted a portion of the water to flow out through the discharge tube. The quantity escaping, however, was small, not only because the bore of the tube was small, but also because the valve was open but for a moment, for as the lever became inclined from its horizontal position the pieces of money slid off, and the dropping of the valve-rod quickly stopped the efflux of the water.