Improvements in Rock Drills.
Year: 1899

page_text: Date of Application, 8th May, 1899-Accepted, 17th June, 1899
COMPLETE SPECIFICATION.
Improvements in Rock Drills.
We, HENRY AYLMER, of the Town of Richmond, in the County of Richmond,
in the Province of Quebec, Canada, Gentleman, and JAMES HENRY PLUMMER,
of 40, Wellesley Street, in the City of Toronto, in the County of York, in the
Province of Ontario, Canada, Gentleman, 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 relates to improvements in drills and the object of the invention
is to design a convenient form of drill in which the sharpened point may be
readily changed when it becomes dull, and a new sharpened point be substituted,
thereby furnishing miners and others with drill points of a first class quality and
temper to be used especially with steam drills and also being very useful for
miners and others in hand work, the point of the bit of course being fastened
to suit the particular work in which it may be employed, and it consists essen.
tially of a circular hole made in the centre of the drill stock and having a reduced
inner end, the bit being made with a corresponding stem to fit into the orifice
in the drill stock and fastened by a pin which extends through the stock and bit,
thereby retaining the bit securely in the stock as hereinafter more particularly
explained.
Fig. 1, is a perspective view of a portion of the drill showing our improved bit.
Fig. 2, is a sectional perspective view of a portion of the drill stock.
Fig. 3, is a perspective view of a bit for a steam drill.
Fig. 4, is a perspective view of a hand drill bit to fit into the same stock.
In the drawings like letters of reference indicate corresponding parts in each
figure.
A is the stock of the drill which is provided at the outer end with a centre
orifice a². This orifice has a reduced inner end a³ leaving an inclined shoulder
at a. Holes a³ and as are bored through the walls of the orifice in the stock
directly opposite each other and also a hole in the point or bit B₁ for the inser-
tion of the pin C¹.
The bit B is provided with a reduced upper portion 63 and a still further
reduced upper portion 64, which are merged into one another by a tapered
shoulder. The reduced upper portion fits into corresponding recesses in the
stock A. Two diametrically opposite holes a and a extend through the stock
opposite the inclined shoulder at whereby if the bit or point becomes jammed an
instrument may be inserted to loosen it by projecting it against the shoulder a*.
The bit or point B is the regular cross bit generally used in steam drills. The
hand bit shown in Fig. 4, may also be employed and secured in position in the
same manner as hereinbefore described.
In the form shown it will be seen that instead of sharpening and tempering the
drill down to a point as heretofore, it is simply necessary to knock out the hold-
fast pin and by lateral pressure of a suitable instrument the point or bit may
be caused to drop out from the stock. A new sharpened point or bit may then be

page_text: inserted and the old one, if not too worn, sharpened at leisure. The point or bit
of course may, it will be understood, be manufactured of a superior quality of
steel to the stock and tempered to a greater nicety.
Having now-particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. In a drill, in combination the stock having a receiving socket in the end
thereof, a bit or point having the inner end adapted to fit into the receiving
socket and an opening leading through the stock into the stock and means for
holding the point in position as and for the purpose. specified.
2. In a drill, in combination the stock having a receiving socket therein with
an inclined or tapering portion, a bit fitted to said socket having a corresponding
tapering portion and an opening leading through the stock to the inclined or
tapering portion of the socket, substantially as described.
3. In a drill, the combination with the stock having the receiving socket
therein, of a bit, having a shank with an inwardly tapering or, inclined portion,
said stock having an opening leading therethrough to the inclined, portion, of
the shank whereby an instrument. can be inserted in said opening and brought
to bear on said incline portion to dislodge the bit, substantially as described.
T
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.