Year: 1887

page_text: Date of Application, 5th July, 1887.
Specification Accepted, 19th Aug., 1887.
[Communicated from abroad by WILLIAM HAMILTON LARIMER, of Torre Haute, in the
County of Vigo and State of Indiana, United States of America, Gentleman.]
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E. 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. :-
.
This invention relates to certain new and useful improvements in drills for
mining purposes and consists substantially in the same as constructed and in such
peculiar arrangement and combinations of parts as will hereinafter be more particularly
explained.
Heretofore in boring rock and coal deposits for creating a cavity or repository
for a blasting compound by which to disintegrate or break up the mass into smaller
fragments it has been customary in many instances to resort to the use of drills of
various forms of construction and which in many instances produce or form openings
whose diameters are of equal extent throughout and frequently the drills have to be
driven in to a considerable depth to produce openings large enough for the purposes
required.
The object of the present invention is to supply a device by which the interior
extremity of the openings may be increased in capacity whereby a greater amount
of blasting compound may be inserted within a mass of rock and coal deposit to
thereby more fully insure an equal separation or disintegration of the mass all as will

page_text: more fully hereinafter appear when taken in connection with the accompanying drawings
wherein―
Fig. 1 represents a view of this improved drill as it appears in operation, and
Fig. 2 is a view in detail of a portion thereof showing the movable blades in an open
position and more fully indicating the construction thereof.
Fig. is a side view of figure 2.
Fig. 4 is a similar view to figure 2 representing the movable blade as when
closed, and
Fig. 5 is a side view thereof.
Reference being had to the several parts by the letters marked thereon A represents
a drill embodying these improvements, the same being preferably of the well known
auger style or form and which in order to illustrate one inanner of using the same is
shown supported or mounted in suitable bearings B the drill being provided with a
handle or crank C, by which it is operated to be turned or revolved. The end of the
drill is formed with a screw point a by which it is readily inserted or started and it is
also squared or flattened as at band is formed at opposite sides with lugs or stops e-c
for a purpose to be hereinafter set forth.
D, D represent blades or knives pivotted to the opposite sides of the flattened
portion b the same having formed on their inner faces a rib or flange d. The opposite
or corresponding edges of these knives are curved or beveled as at by which they are
caused to separate or spread apart when brought into contact with the walls of the
cavity that is to be enlarged to effect a cutting action. The lugs or shoulders c, c,
serve to prevent the knives or blades from being spread too far backward and they
also serve to receive or sustain a part of the pressure necessarily exerted in the
operation of the drill thereby relieving the pivot from strain and preventing breakage
thereof. The flanges or ribs d are for the purpose of preventing the blades from
closing too far in or across each other by coming in contact with or abutting against.
the screw point a and it will be seen on reference to figure 4 that when the blades are
closed together their curved cutting edges produce a notch or V-shaped opening by
which it is evident that when the drill is inserted in an opening y previously formed in
a mass of coal or rock and the same pressed against the rear wall thereof the said
knives or blades will be caused to gradually spread outward as the drill is being
operated.
The operation of this invention is as follows: when it is desired to increase or
enlarge the capacity of a drill-opening in a mass of rock or coal the drill A is pro-
jected into the opening and the same revolved or turned in the ordinary manner of
operating a drill, and gradually as pressure is exerted the knives will cut away the
portions around the opening with which they come in contact until they are spread
apart to their fullest extent and made to rest or bear against the shoulders e, e and it is
evident that the said blades will act to cut out or increase the size of the cavity. In
operation the screw point is continually entering the mass in advance of the blades
thus acting to start a way for and assist in the operation of said blades in that it
breaks or loosens the particles of the mass.
From the foregoing description it is thought the construction and operation of this
improved drill will be thoroughly understood, and I desire to state that I do not wish
to be understood as limiting myself to the details of construction and arrangements of
parts as shown for it is evident that various modifications or changes thereof could be
resorted to and still come within the scope of this invention.
Having now particularly described and ascertained the nature of the said invention
as communicated to me by my foreign correspondent, and in what manner the same is
to be performed I declare that what I claim is :-
1. A drill of the character described having knives or blades pivotted to its
opposite sides whose corresponding edges are curved or beveled the same being formed
with the screw point a designed to operate in advance of the blades when revolved
or rotated and shoulders c, e limiting the spread of the knives substantially as
described.

page_text: 2. The combination with the drill formed with screw point a designed to operate in
advance of the blades when revolved or rotated and shoulders c, e limiting the spread
of the blades, of the oppositely pivotted blades D, D having ribs d on their inner faces
designed to abut against the point a for preventing the said blades from crossing each
other when closed together, substantially as described.
3. The combination with a drill of the character described formed with lugs or
shoulders, e, c and screw point a and flattened as at 6 of knives D, D pivotally attached
and formed with ribs d on their inner faces substantially as set forth.