Improvements in Rock drills, Coal-diggers, or Earth-cutters.
Year: 1890

page_text: Date of Application, 19th Aug., 1890-Accepted, 29th Nov., 1890
CUMPLETE SUBGIFICA LIQN.
Improvements in Rock drills, Coal-diggers, or Earth-cutters.
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, Buildor, 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 consists firstly in the employment of a number of elastic bands or
springs as connections between a reciprocating collar and the spindle of a percussive
drill, whereby we are enabled to work said drill rapidly without giving undue shocks
to the apparatus.
Secondly in mounting the motor for driving this drill in such a position as that its
centre of inertia is approximately in a line with and immediately above the axis of the
drill, thereby preventing the side shaking which is observable when the motor is
mounted alongside the drill.
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 a porcussive drill constructed and driven according
to our invention, whilst
Figure 2 is a vertical central section of same, drawn on a larger scale, and
Figure 3 is a plan thereof, whilst
Figure 4 is a vertical transverse section on line 4-4 Figure 2.
Similar letters of reference indicate the same parts in all the figures.
A represents a percussive drill mounted in a socket or otherwise on the forward end
of the spindle B. In suitable positions upon this spindle B, are keyed or otherwise
secured a pair of collars C, having radial T or other suitably shaped pins or lugs c,
around each of which passes a rubber band D, whose other end is secured to a similar
lug upon a collar E, fitted loosely upon a tube d, encircling the drill spindle B.
Outside the two collars C and the ends of the tube d, a pair of collars c¹ are secured
upon the spindle B by pinning, keying, or otherwise. At the rear end of the
cylinder F, enclosing the just mentioned rubber springs and collars, is a small hand
wheel G, which is provided with a key or feather fitting into a groove g, cut in the
spindle B, and which is capable of being turned by hand so as to correspondingly
turn the drill spindle and therefore the drill A, to ensure a perfectly round hole
being drilled and to equalise the strain upon said drill. The sliding collar E is
formed with an upwardly projecting lug e, which is connected by a forked connecting-
rod to a crank pin 1, projecting from a pair of crank discs h³, keyed to the spindle i,
one on each side of the motor 1. These said crank discs 2 are preferably provided
with several holes for receiving the crank pin 4, in order that the throw of the
collar E may be varied according to the stroke which it is desired to give to the
drill. Said motor may be of any suitable construction, but it is preferably made of
such a form as to bring its centre of gravity as low as possible.
One convenient form
for this purpose is the well-known Gramme motor, which is illustrated in our
drawings, wherein J represents the field magnets and K a ring armature, whose
construction will of course be varied according to the amount of power required and
the character of the current or potential employed, as will be well understood by
electricians. The commutator and brushes-L and M respectively-are preferably
mounted upon the spindle i of the motor inside the crank discs / as clearly illustrated
n Figures 3 and 4, in order that the whole of the motor may be enclosed by a shield
or cover N of sheet metal or other material.

page_text: The whole of the motor I and the cylinder F, together with the movable collar E
and drill spindle B, are mounted upon a pair of wheels O whose axle o is preferably
cranked, as illustrated in Figure 4, the better to support such parts of our improved
rock drill.
It will be readily understood by all persons skilled in the art to which our inven-
tion relates that our improved rock drill will be very useful for undercutting or
"getting" coal, because it can easily be shifted about upon the wheels O, and can be
directed to any required point; moreover it is of simple construction, and therefore
not liable to get out of order, and owing to the elastic connections D between the
motor and the drill itself, the latter can be worked close up to the face of the rock
the siroke being regulated or compensated for by such elastic connections, as will be
well understood.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is :-
1. In a rock drill, coal digger or earth cutter, the combination with a reciprocating
drill spindle (such as B) of a collar (such as E) adapted to slide freely to and fro
upon such spindle, together with a number of elastic or other springs (such as D)
connecting said sliding collar with a pair of collars (such as () secured upon said
spindle in such a manner that the latter is free to turn in said collars whilst at the
same time it is prevented from sliding longitudinally through them, substantially as
and for the purpose herein described and explained and as illustrated in our
drawings.
2. In a rock drill, coal digger or earth cutter the combination of a cylinder (such
as F) through which can slide the spindle (such as B) of a reciprocating drill (such
as A) with an electro motor (such as I) mounted upon said cylinder in such a manner
as that the centre of inertia of said motor is immediately over the axial line of the
drill, substantially as and for the purposes herein described and explained, and as
illustrated in our drawings.
Dated this Eighth day of July 1890.
W. BLANCH BRAIN.
ARTHUR J. ARNOT.
FRANK BAKER.