It does not seem as if the band or endless saw should render the same
services in sawing stone as in working wood and metals, for the
reason that quite a great stress is necessary to cause the advance of
the stone (which is in most cases very heavy) against the blade. Mr.
A. Auguste, however, has not stopped at such a consideration, or,
better, he has got round the difficulty by holding the block
stationary and making the blade act horizontally. Fig. 1 gives a
general view of the apparatus; Fig. 2 gives a plan view; Fig. 3 is a
transverse section; Fig. 4 is an end view; Figs. 5, 6, and 7 show
details of the water and sand distributer; and Figs. 8, 9, and 10 show
the pulleys arranged for obtaining several slabs at once.
[Illustration: FIG. 1 AUGUSTE'S STONE SAW.]
[Illustration: FIG. 2 AUGUSTE'S STONE SAW.]
[Illustration: FIGS. 3 and 4 AUGUSTE'S STONE SAW.]
[Illustration: FIGS. 5 through 10 AUGUSTE'S STONE SAW.]
The machine is wholly of cast iron. The frame consists of four
columns, A, bolted to a rectangular bed plate, A', and connected above
by a frame, B, that forms a table for the support of the transmission
pieces, as well as the iron ladders, _a_, and the platform, _b_, that
supports the water reservoirs, C, and sand receptacles, C'.
Between the two columns at the ends of the machine there are two
crosspieces, D and D', so arranged that they can move vertically, like
carriages. These pieces carry the axles of the pulleys, P and P',
around which the band saw, S, passes. In the center of the bed plate,
A', which is cast in two pieces connected by bolts, there are ties to
which are screwed iron rails, _e_, which form a railway over which the
platform car, E, carrying the stone is made to advance beneath the
saw.
The saw consists of an endless band of steel, either smooth or
provided with teeth that are spaced according to the nature of the
material to be worked. It passes around the pulleys, P and P', which
are each encircled by a wide and stout band of rubber to cause the
blade to adhere, and which are likewise provided with two flanges. Of
the latter, the upper one is cast in a piece with the pulley, and the
lower one is formed of sections of a circle connected by screws. The
pulley, P, is fast, and carries along the saw; the other, P', is
loose, and its hub is provided with a bronze socket (Figs. 1 and 4).
It is through this second pulley that the blade is given the desired
tension, and to this effect its axle is forged with a small disk
adjusted in a frame and traversed by a screw, _d'_, which is
maneuvered through a hand wheel. The extremities of the crosspieces, D
and D', are provided with brass sockets through which the pieces slide
up and down the columns, with slight friction, under the action of the
vertical screws, _g_ and _g'_, within the columns.
A rotary motion is communicated to the four screws simultaneously by
the transmission arranged upon the frame. To this effect, the pulley,
P, which receives the motion and transmits it to the saw, has its
axle, _f_, prolonged, and grooved throughout its length in order that
it may always be carried along, whatever be the place it occupies, by
the hollow shaft, F, which is provided at the upper extremity with a
bevel wheel and two keys placed at the level of the bronze collars of
its support, G. The slider, D, is cast in a piece with the pillow
block that supports the shaft, _f_, and the bronze bushing of this
pillow block is arranged to receive a shoulder and an annular
projection, both forged with the shaft and designed to carry it, as
well as the pulley, P, keyed to its extremity. Now the latter, by its
weight, exerts a pressure which determines a sensible friction upon
the bushing through this shoulder and projection, and, in order to
diminish the same, the bushing is continuously moistened with a
solution of soap and water through the pipe, _g_, which runs from the
reservoir, G'.
The saw is kept from deviating from its course by movable guides
placed on the sliders, D and D'. These guides, H and H', each consist
of a cast iron box fixed by a nut to the extremity of the arms, _h_
and _h'_, and coupled by crosspieces, _j_ and _j'_, which keep them
apart and give the guides the necessary rigidity.
The shaft, _m_, mounted in pillow blocks fixed to the left extremity
of the frame, receives motion from the motor through the pulley, _p_,
at the side of which is mounted the loose pulley, _p_. This motion is
transmitted by the drum, M, and the pulley, L, to the shaft, _l_, at
the other extremity. This latter is provided with a pinion, _l'_,
which, through the wheel, F', gives motion to the saw. The shaft, _m_,
likewise controls the upward or downward motion of the saw through the
small drums, N and _n_, and the two pairs of fast and loose pulleys,
N' and _n'_. This shaft, too, transmits motion (a very slow one) to
the four screws, _g_ and _g'_, in the interior of the columns, and the
nuts of which are affixed to the sliders, D and D'. To this effect,
the shaft, _q_, is provided at its extremities with endless screws
that gear with two wheels, _q_', with helicoidal teeth fixed near the
middle of two parallel axes, _r_, running above the table, B, and
terminating in bevel wheels, _r'_, that engage with similar wheels
fixed at the end of the screws, _g_ and _g'_.
The car that carries the block to the saw consists of a strong frame,
E, mounted upon four wheels. This frame is provided with a pivot and a
circular track for the reception of the cast iron platform, E', which
rests thereon through the intermedium of rollers. Between the
rails, _e_, and parallel with them, are fixed two strong screws, _e'_,
held by supports that raise them to the bottom of the car frame, so
that they can be affixed thereto. When once the car is fastened in
this way, the screws are revolved by means of winches, and the block
is thus made to advance or recede a sufficient distance to make the
lines marked on its surface come exactly opposite the saw blade.
In sawing hard stones, it is necessary, as well known, to keep up a
flow of water and fine sand upon the blade in order to increase its
friction. Upon two platforms, _b_, at the extremities of the machine,
are fixed the water reservoir, C, and the receptacles, C', containing
fine sand or dry pulverized grit stone. As may be seen from Figs. 5
and 6, the bottom of the sand box, C', is conical and terminates in a
hopper, T, beneath which is adjusted a slide valve, _t_, connected
with a screw that carries a pulley, T'. By means of this valve, the
bottom of the hopper may be opened or closed in such a way as to
regulate the flow of the sand at will by acting upon the pulley, T',
through a chain, _t'_, passing over the guide pulley, _t²_. A rubber
tube, _u_, which starts from the hopper, runs into a metal pipe, U,
that descends to the guide, H, with which it is connected by a collar.
Under the latter, this pipe terminates in a sphere containing a small
aperture to allow the sand to escape upon an inclined board provided
with a flange. At the same time, through the rubber tube, _c_, coming
from the reservoir, C, a stream of water is directed upon the board in
order to wet the sand.
As the apparatus with but a single endless saw makes but two kerfs at
once, Mr. Auguste has devised an arrangement by means of which several
blades may be used, and the work thus be expedited.
Without changing the general arrangements, he replaces the pulleys, P
and P', by two half drums, V and V' (Figs. 8, 9, and 10), which are
each cast in a piece with the crosspieces, D² and D³, designed to
replace D and D', and, like them, sliding up and down the columns, A,
of the frame. Motion is transmitted to all the saw blades by a cog
wheel, X, keyed to the vertical shaft, _f_, and gearing with small
pinions, _x_, which are equally distant all around, and which
themselves gear with similar pinions forming the radii of a succession
of circles concentric with the first. All these pinions are mounted
upon axles traversing bronze bearings within the drum, which, to this
effect, is provided with slots. The axles of the pinions are prolonged
in order to receive rollers, _x'_, surrounded with rubber so as to
facilitate, through friction, the motion of all the blades running
between them.
The other drum, V', is arranged in the same way, except that it is not
cast in a piece with the carriage, D³, but is so adjusted to it that
a tension may be exerted upon the blades by means of the screw, _d_,
and its hand wheel.
Through this combination, all the blades are carried along at once in
opposite directions and at the same speed.--_Publication
Industrielle._
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