Improvements in Means and Apparatus for Sawing Stone, or other Hard Substances.
Year: 1899

page_text: Date of Application, 29th Nov., 1899-Accepted, 30th Dec.,
1899
COMPLETE SPECIFICATION.
Improvements in Means and Apparatus for Sawing Stone, or other
Hard Substances.
I, FÉLIX FROMHOLT, of 44, Rue de Montmartre, Saintouen (Seine), in the
Republic of France, Manufacturer, do hereby declare the nature of this invention,
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement, that is to say:-
Granite and other hard stones are ordinarily sawn by interposing between
a horizontal reciprocating blade and the block to be sawn, granules of hard
white cast iron or of tempered steel, the blade serving as the vehicle for carrying
these granules or globules in wearing away the stone. This process has not up
to the present time been practically employed for continuous or circular saws,
as the globules do not remain adherent to the revolving blade but are thrown off
to a distance.
My present invention has for its object methods of fixing the granules or
globules sufficiently firmly to the blade in machines of this kind, and for this
purpose I make use of magnetism.
My improved process may be made use of in two different ways; that is to
say, either by magnetizing the granules themselves which are then supplied to
the machine where they remain adherent to the blade by magnetic attraction;
or by magnetizing the blade itself to which they are supplied.
--
The magnetization of the globules themselves may be effected by passing
them through a suitable solenoid.
In order to magnetize the blade for the purpose of fixing, or causing the
granules or globules described to adhere, the arrangement may be used illus-
trated in Figures 1 and 2 of the accompanying drawing, which is in illustration
of my invention, Figure 1 being a transverse section, and Figure 2 a front view.
a is the axis or spindle having fixed upon it a disc or plate upon which are
fixed a series of electro-magnetic bobbins c, c, connected together by a ring d
upon which is bolted one end of the axes or cores of the bobbins, the other ends
of the cores passing through the plate b. The plate is provided with a disc e
of a highly magnetic metal, such as cast steel for instance, which is screwed
firmly upon the plate b. Upon the same spindle a are fixed two brass insulated
connecting rings f,f against which the brushes for causing the passage of an
electric current through the electro-magnetic coils, are pressed.
The electro-magnets may be of any suitable kind. Preferably, however, I
use that well known as Weber's circular electro-magnet.
It may be arranged, as illustrated in Figures 3 and 4, in the interior of the
plate fixed upon the spindle a, so as to be protected from shocks or injury, or
from the presence of water.
Finally, it is indispensable to supply a sufficient quantity of water to the
apparatus to prevent heating.
In both arrangements of the apparatus described, the spindle a may be hollow.
so as to allow a stream of water to be introduced through it into the centre of
the disc.

page_text: The block to be operated upon is placed upon a carriage which can be moved
backward and forward, as in an ordinary planing machine for metals, or upon a
double carriage such as that used with diamond circular saws.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
The use of magnetism, either in the form of the residual magnetism remain-
ing in magnetized metallic globules, or of an electro-magnetic current which
serves to cause such metallic globules to be retained upon the rapidly moving
surface which operates with them to cut stone or other hard substances, substan-
tially as described and illustrated.
LT
EDWARDS AND CO.,
Chartered Patent Agents, .
65 and 66, Chancery Lane, London, Agents for the Applicant.