As the driving belts are mounted on pulleys, G, of a diameter
proportioned to the velocity of the shafting, the iron pinions, h, in
order to produce 60 revolutions per minute in the first shaft, H, gear
on each side with the intermediate wheels, E, and these actuate the
two bronze pinions, a a, that are mounted on the extremities of the
cylinders, A A. The axle, D, of the intermediate wheels does not revolve
with them, but is capable of rising and descending in the elongated
aperture that traverses the frames, B. The displacement of this axle is
secured through the arms, L L, whose extremities articulate on the one
hand with the cylinders, A A, and on the other with D. The result of
this is that every displacement upward of the top cylinder corresponds
to a different position of the intermediate shaft, and one that is
always equidistant from the centers of the cylinders, A A, thus securing
a constant gearing of the wheels in all the positions of the cylinders,
A A.
The diagram in Fig. 7 shows the relative displacements of all these
parts, as well as those of the scraper guide, C. The diameter to be
obtained is determined beforehand by the two contact screws, P.
The whole thus regulated, the bar of iron, still very hot, coming from
the ordinary rollers, is straightened up, if need be, by a few blows of
a hammer, so that it may roll forward over the pavement, N, between the
rounding cylinders, A A; these being held apart sufficiently to allow
of its easy introduction. Next, a few revolutions of the winches that
control the screws suffice to lower the upper cylinder to the exact
position limited by the contact screws, P, and the bar is rolled between
the two cylinder tables with a constant velocity in the generatrices. As
a consequence, the number of revolutions made is so much the greater in
proportion as the diameter of the shaft is smaller with respect to that
of the cylinders.
It should be remarked that the bar, during its rotation under pressure,
is held by the guide, C, so that its diagrammatic axis (Fig. 7) exceeds
the line, A A, joining the centers of the cylinders just enough to
prevent its escape to the opposite, and so that the pressure upon the
said guide (which performs the role of scraper) is merely sufficient to
detach the scales which form during the operation.
Under such conditions, and at a velocity of 30 revolutions per minute in
the two cylinders, it will take but a fraction of a minute to finish
a bar the length of the table, that is to say, 1.5 meters. Then, by
loosening the upper cylinder, the bar may be easily shoved along in one
direction or the other, so as to continue the finishing operation
on successive lengths. This moving of the bar forward is further
facilitated by the aid of a clamp with rollers and a movable socket,
V (Figs. 8 and 9). For large diameters (150 millimeters and beyond)
traction is employed by the aid of two small windlasses placed opposite
each other, and at a distance apart twice the greatest length of the
bars to be finished. The chains of these windlasses are attached to the
extremities by clamps that lock by the pulling exerted.
The details of the arrangement of the saws (Figs. 5 and 6) show that to
make a section of the ends or of any other part of the bar, it is only
necessary to lower the lever of one them. By reason of the contrary
rotation of the bar, the effective stress on the lever will be very
moderate, while the cut produced will be a clean and quickly performed
one. It should be remarked that, as a consequence of the cone on the
projecting extremity of the cylinder journals (Fig. 5), and on the
rollers that control the saws, it is only necessary to move the lever to
the right or left in order to stop the motion of each of the saws. These
latter, to prevent all possibility of accident, are inclosed within
semicircular guards. Finally, the controlling rollers are made of a
material which is quite elastic (compressed cardboard, for example), so
that they may roll smoothly and adhere well.
From what precedes, it will be seen that round iron bars of any diameter
will come from this apparatus completely finished. It will be seen
also that with cylinders of suitable profile, there might likewise be
finished axles, or pieces that are more or less conical as well as those
provided with shoulders.
The apparatus may, if preferred, be driven by small special motors
affixed to the frame. Such an arrangement, which is more costly than the
preceding, is, nevertheless, indicated in cases where shafting would be
in the way.
The weight of the materials entering into the construction of this
machine, proposed by Mr. Chuwab, includes about 15 tons of metal,
of which 5,000 kilogrammes are for the two tempered cylinders; 250
kilogrammes of iron screws, and 350 of bolts; and 500 kilogrammes of
bronze, 90 of which are for nuts.--_Revue Industrielle_.
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