IMPROVEMENTS IN MACHINERY AND APPARATUS FOR EXCAVATING COAL AND OTHER MINERALS, AND IN THE MODE OF ACTUATING SUCH MACHINERY
Year: 1874

page_text: LETTERS PATENT to Henry Wilde, of Manchester, in the County
of Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN
MACHINERY AND APPARATUS FOR EXCAVATING COAL AND OTHER MINERALS, AND
IN THE MODE OF ACTUATING SUCH MACHINERY."
Sealed the 26th June 1874, and dated the 2nd May 1874.
PROVISIONAL SPECIFICATION left by the said Henry Wilde at the
Office of the Commissioners of Patents, with his Petition, on the
2nd May 1874.
I, HENRY WILDE, of Manchester, in the county of Lancaster,
Engineer, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN MACHINERY AND APPARATUS FOR EXCAVATING COAL AND OTHER
MINERALS AND IN THE MODE OF ACTUATING SUCH MACHINERY," to be as
follows:-
Whereas many attempts have been made to substitute machinery for
hand labour in excavating coal and other minerals, but the means of

page_text: supplying the motive power to actuate such machinery has hitherto been
attended with so much difficulty and expense, that little or no sub-
stantial economy has been effected by its use.
Now my Invention consists in substituting for the force of compressed
air or other power now employed, the motive power produced by
magnetism and electricity by which the excavating is effected in a more
economical manner than can be done by hand labour, and with greater
comfort to the men engaged in the work.
In order that this Invention may be carried into effect, powerful
electric currents for producing the motive power are generated by a
magneto-electric or an electro-magnetic induction machine driven by a
steam engine. The electro-magnetic induction machine I prefer to use
for this purpose is the one with multiple armatures described in the
Specification of Letters Patent granted to me on the 23rd day of March
1867, and numbered 842. The direct or persistent current from this
machine is then transmitted through metal conductors of suitable thick-
ness to the electro-magnetic motor machine or machines actuating the
excavators. These electro-motive power machines may be constructed to
produce either a continuous rotary or a reciprocating motion of their
armatures, but as the latter motion is more effective than the former on
account of its percussive action in the disintegration of a brittle material
like coal, I will describe machines constructed on the reciprocating
principle.
A number of cylindrical electro-magnets are arranged vertically in a
circle with their alternating north and south poles uppermost. The iron
cores of these magnets are prolonged and shaped in such a manner as to
allow a corresponding number of armatures to oscillate between them.
The armatures are fixed at right angles to a common base plate of iron
mounted on a vertical axis concentric with the circle of magnets, about
which axis the plate together with its armatures oscillates. To the plate
of iron a projecting radial arm is fixed the end of which carries a pick
head for excavating the coal.
The action of the electro-magnets and armatures is as follows:-When
the electric current is transmitted through the coils of the electro-
magnets, the armatures are suddenly and forcibly attracted to the pro-
longations of the iron cores, and thereby cause the pick at the end of the
radial arm to strike violently against the face of the seam of coal to be
operated upon. At the completion of each stroke the 'motion of the

page_text: . .
armatures establishes electric contacts, which short circuit the current
passing round the electro-magnets, and they thereby become de-
magnetized and allow the armatures to be withdrawn from the magnets
in readiness for another stroke. The withdrawal of the armatures is
effected by means of an antagonistic spring, the action of which also
reopens the electro-magnetic circuit at the commencement of each
stroke. Brass studs projecting slightly above the surface of the iron
prevent the armatures from coming into immediate contact with the
iron cores, and the residual magnetism of the electro-magnets is
neutralized by breaking automatically the electro-magnetic circuit after
the short circuit is made, and shunting the current through a few turns
of wire wrapped round the electro-magnets in a direction contrary to
that required to magnetize them normally. The system of electro-
magnets and armatures is made to move round a vertical axis fixed on
a carriage which slides on a short iron bed placed parallel with the face
of the seam of coal. The carriage is made to traverse along the bed by
means of a screw for the purpose of bringing successive portions of the
seam of coal under the action of the pick. At each stroke of the pick
it is advanced automatically into the seam of coal by means of a pall and
ratchet wheel, and suitable wheel work actuated by the reciprocating
armatures, provision is also made by means of a screw for raising and
lowering the pick to suit the width of the cut, as well as its distance
from the lower face of the seam.
In another form of machine a single electro-magnet formed of
rectangular plates of iron is substituted for the cylindrical magnets
above described, and a reciprocating motion is given to the pick by
means of an armature hinged to one of the poles of the electro-magnet
before which it oscillates. All the arrangements for opening and
closing the electro-magnetic circuits, and for bringing successive
portions of the work under the operation of the pick, are similar to those
in the machine above described.
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A number of these electro-motive power machines may be actuated
by the same magneto-electric or electro-magnetic induction machine, in
which case the coils of all the electro-magnets are arranged in one con-
tinuous circuit, and as each electro-magnet is short circuited at the
completion of the stroke of its armature, no interruption of the electric
circuit occurs, and the machines exercise no adverse influence on each
other. A large electro-magnet is placed in the circuit of the electro-motive

page_text: power machines for the purpose of correcting the intermittent action of
the currents from the electro-magnetic induction machine.
The steam engine and electro-magnetic machine may be worked either
above or below the surface of the ground, and the conductors trans-
mitting the electric current to the motor machines may form one
continuous metallic circuit. In some cases however the return con-
ductor may be dispensed with by extending metal conductors in contact
with moist earth into which the electricity is discharged.
My Invention may also be applied for working excavating machines
with rotating cutters, or the motion of an electro-motive power machine
with rotating armatures may be converted into a reciprocating motion
by means of cranks and levers.