An Improved Electrical Rock-drill, Coal-digger, or Earth-cutter.
Year: 1890

page_text: Date of Application, 19th Aug., 1890-Accepted, 27th Dec., 1890
COMPLETE SPECIFICATION.
An Improved Electrical Rock-drill, Coal-digger, or Earth-cutter.
We, WILLIAM BLANCH BRAIN, of "Abernethy" Hotham Street St. Kilda near
Melbourne in the Colony of Victoria, Mining Engineer, ARTHUR JAMES ARNOT,
of Fink's Buildings, Melbourne aforesaid, Electrical Engineer, and FRANK BAKER,
of Byron Street St. Kilda aforesaid, Builder, 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:—
Our invention of an improved electrical rock-drill, coal-digger or earth-cutter
consists essentially in combining an earth-boring auger with an electro-motor by
providing the latter with a comparatively large hollow spindle, through which a rod
or spindle secured to the auger can pass freely longitudinally and at the same time
be caused to rotate therewith. This said hollow spindle has the commutator and
armature secured to it in the ordinary manner.
Having now generally described and ascertained the nature of our invention and
in what manner the same is to be performed we will proceed to describe the same
more particularly with the aid of the accompanying drawings, wherein,
Figure 1 is a side elevation of an electrically driven rock-drill constructed
according to our invention illustrating same secured in position in a drive or
beading in a mine, whilst,-
Figure 2 is a rear elevation of same, and,
Figures 3, 4 and 5 are respectively a side clovation a rear elevation and a front
elevation of our improved rock-drill, drawn to a somewhat larger scale than the
preceding figures in order to better illustrate its construction; whilst,-
Figure 6 is a horizontal central section thereof.
Similar letters of reference indicate the same or corresponding parts in all the
figures.
A represents an earth-boring auger, which is screwed or otherwise secured upon
the forward end of a rod or spindle B, passing freely through the hollow spindle C of
an electro-motor, as clearly illustrated in said figures.
According to our invention this said motor is so constructed that it can be moved
bodily into any desired position-say for instance along the face of a seam of coal-
and be clamped or secured in such a position that the spindle B and auger A may
be pressed forward in the desired direction. We prefer to arrange a comparatively
long bed-plate D parallel to the face of the coal or work and to bevel the edges of
said bed-plate in order to admit of the employment of a holding-down clamp or lever d,
pivoted to the underside of a bracket d¹ secured to the forward ends of the pole
pieces e of the field magnets E. This clamp d, is adapted to grip the bed-plate
against a pair of clamp-pieces 2, at the other end of the field-magnets, whilst said
bed-plate D may be secured in position by any suitable means, such for instance, as
the screw-threaded holding-down post F, and it will be readily understood that the
combined motor and drill may be shifted along such bed-plate provided the clamps d
are first slackened.
The armature G is secured upon the hollow spindle C, and of course rotates there-
with. It may be of any suitable construction such for instance as an ordinary
Siemens or Gramme ring. The commutator H is likewise secured upon the hollow
spindle C, whilst the brushes I are supported by a carrier i, which is capable of being
rotated at will upon a projecting sleeve or other fixed part of one of the bearings in
which the hollow spindle (runs.
It will be noticed that with this construction of
motor it is possible to get the spindle much closer to the ground than with the
ordinary form, thus enabling the auger A to work as close to the floor of the drive
or heading as required. It will of course be obvious that said motor may be driven

page_text: by a current derived from any suitable source, as for instance a dynamo, such current
being led to said motor along any conveniently arranged leads. The spindle B is
prevented from rotating independently of the hollow spindle C by a feather 1,
projecting into a long groove or key-way cut from end to end of said spindle B. In
order to facilitate the feeding forward of the auger we secure a disc or handle
to the rear end of the spindle B in order that the latter may be propelled forward by
the pressure of the hand upon the knob or handle as will be well understood on
reference to Figure 1.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
An improved electrical rock-drill coal-digger or earth-cutter consisting essentially
in the combination with an earth-boring auger, of an electro-motor having a hollow
spindle, such as C, through which the spindle connected to such auger can pass freely
longitudinally and at the same time be caused to rotate therewith substantially as
and for the purposes herein described and explained and as illustrated in our
drawings.
Dated this Eighth day of July One thousand eight hundred and ninety.