Improved Means and Appliances for Operating the Stocks of Percussive Drills and other like apparatus.
Year: 1891

page_text: Date of Application, 11th June, 1891
Complete Specification Left, 4th Apr., 1892-Accepted, 4th June, 1892
PROVISIONAL SPECIFICATION.
Improved Means and Appliances for Operating the Stocks of
Percussive Drills and other like apparatus.
I, WILLIAM A'COURT GRANVILLE BIRKIN, of The Park, Nottingham,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to improved means and appliances for operating the stocks
of drills and other like apparatus so as to give a reciprocating motion.
For this purpose, I adopt a novel form of combination of an electro-magnet and
solenoid, which I combine in the following manner.
I enclose a solenoid in a shell or jacket of soft iron of a suitable thickness. I
then place a soft iron disc on one end of the shell or jacket, and connected thereto
and in the centre and fastened to the disc I place a soft iron core which said core
I insert into the solenoid so as to partially fill up the hollow helix of the solenoid
to any desirable depth.
When desirable, I may attach an annular ring at the further or unclosed end
of the jacket or shell, which annular ring may be broad or narrow according to
convenience.
From the above, it will be seen that independent of the action of the solenoid, an
electro-magnet is provided, one pole of which is the end of the inserted core, the
other pole being the annular ring or end of the jacket or shell.
Upon a moveable plunger, I attach a disc of soft iron, I insert one end of the
plunger a short distance within the solenoid, the result being that on sending a
current through the coils of the solenoid, the plunger is sucked into said solenoid.
At the same time, the magnet attracts, thus yielding a very powerful pull over a
long range, unobtainable by the action of a magnet or solenoid alone when utilising
the same electric energy.
I attach the drill bar in a suitable way to the plunger, at a given point of the
stroke the current is cut off by an automatic switch, or otherwise, and the return
stroke is given by the aid of one or more springs, which has or have been com-
pressed during the stroke, but may also obtain the return stroke by means. of
another similar combination of a magnet and solenoid, or by a solenoid alone, or by
a magnet alone, instead of by means of one or more springs.
In order to avoid the destructive effect of sparking due to breaking of current, I
employ a small air blower, actuated automatically by the movement of the plunger,
or otherwise, the device being so arranged that an air blast is delivered upon the
spark at the very moment when the spark appears. The combined magnets and
solenoids may be in pairs.
I obtain the twisting of the drill stock during its return stroke in a suitable
way.

page_text: COMPLETE SPECIFICATION.
Improved Means and Appliances for Operating the Stocks of
Percussive Drills and other like apparatus.
1. WILLIAM A'COURT GRANVILLE BIRKIN of The Park, Nottingham,
Engineer 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 :-
My invention relates to improved means and appliances for operating the stocks
of drills and other like apparatus so as to give a reciprocating motion.
For this purpose I adopt a novel form of combination of an electro-magnet
and solenoid which I combine in the following manner; I enclose a solenoid in a
shell or jacket of soft iron of a suitable thickness, I then place a soft iron disc on
one end of the shell or jacket and connected thereto, and in the centre and fastened
to the disc I place a soft iron core, which said core I insert into the solenoid so as
to partially fill up the hollow helix of the solenoid to any desirable depth.
When desirable I may attach an annular ring at the further or unenclosed end
of the jacket or shell, which annular ring may be broad or narrow according to
convenience.
From the above it will be seen that independent of the action of the solenoid an
electro-magnet is provided, one pole of which is the end of the inserted core, the
other pole being the annular ring or end of the jacket or shell.
Upon a movable plunger I attach a disc of soft iron, I insert one end of the
plunger a short distance within the solenoid, the result being that on sending a
current through the coils of the solenoid the plunger is sucked into said solenoid.
At the same time the magnet attracts, thus yielding a very powerful pull over a
long range unobtainable by the action of a magnet or solenoid alone when utilizing
the same electric energy.
1 attach the drill bar in a suitable way to the plunger, at a given point of the stroke
the current is cut off by an automatic switch or otherwise and the return stroke is
given by the aid of one or more springs which has or have been compressed during
the stroke, but I may also obtain the return stroke by means of another similar
combination of a magnet and solenoid, or by a solenoid alone, or by a magnet alone
instead of by means of one or more springs.
In order to avoid the destructive effect of sparking due to breaking of current
an air blast from a blower is delivered upon the spark at the very moment when
the spark appears.
The combined magnets and solenoids may be in pairs.
I obtain the twisting of the drill stock during its return stroke in a suitable
way.
My invention will be understood by reference to the annexed drawings.
Figure 1, is a part sectional elevation of a rock drill in which my improvements
are identified and a spring employed for delivering the blow.
A is the soft iron shell, or jacket enclosing a solenoid B. A disc C of soft
iron is attached to one end of the jacket A, a core D being screwed to the disc
and within the solenoid. A plunger E is adapted to move freely reciprocatingly in
the solenoid in. one direction under the influence of a spring F and in the other
direction by magnetic attraction between the pole D and the plunger E and the
pole C and soft iron piston G formed in a piece with the plunger.
The spring F is contained within the chamber H said chamber being screwed
into the iron piston G and moves with same. A rod I is screwed into the pole D
the other end terminating in a head J within the spring chamber and against which
the spring abuts for compression when the core is drawn into the solenoid by
magnetic attraction during the reciprocating movement. The solenoid and jacket
are surrounded and enclosed by the barrel portion K' of the frame K. The drill
stock may have imparted to it a semi-rotary movement in the ordinary manner, or

page_text: it may have a semi-rotary movement in one direction and a straight travel in
the other in the manner hereinafter fully described with reference to Figure 2.
The apparatus is mounted upon a stand K of ordinary construction with feed
Bcrew movement L of the requisite length. The electro motive force may be
derived from any available source and is carried by wires through the handle:
to the studs N, N', the circuit being closed by the contact P under the action
of a spring Q and broken by the plunger E pressing the sliding rod R against
the tappet S and moving the contact P away from the studs N, N.
The action is as follows:-
The current circulating around the solenoid B magnetizes the jacket A and
core D and creates an intense magnetic field in the hollow of the solenoid into-
which is attracted the plunger E under the combined influence of said magnetic
field upon the plunger and the outer jacket A upon the piston G. During this
movement the spring F is compressed and the contact P moved away from the
studs N, N¹, to break the circuit when the whole is demagnetized and allowed
to resume its normal position with great rapidity and momentum by the spring F.
In cases where I find it convenient to dispense with the spring F, I use two or
more solenoids.
The example shown at Figure 2 illustrates my invention as applied with three
solenoids enclosed within a case the central portion of which may preferably be of
non-magnetizable material.
Figure 3 is a section on line a, b, of Figure 2 showing the method of producing
semi-rotary movement, say on the backward stroke with a straight forward move-
ment and
Figure 4 is a diagram of the solenoid connections.
The plunger or iron core E is shown at its extreme backward position and within.
the coils B, B'. At the rear end of the plunger E is an extension U, say of gun
metal, with sinuous and straight grooves, V, W, respectively (see Figure 3 also).
Two ratchet wheels X, Y, are arranged upon the extension U one with ribs ✗¹ of
sinuous shape adapted to engage in the corresponding grooves X and the
others with straight ribs for engaging into the grooves Y. The ratchet wheels
are prevented from turning, except in one direction, by spring pawls or stops c, d,
so that upon the backward movement of the piston, the ratchet wheel engaging in
the sinuous grooves is prevented from turning by the stop c the wheel Y at the.
same time being free to revolve the plunger has consequently a twist imparted to it
proportionate to the pitch of the groove. On the reverse or forward movement of
the plunger, the ratchet wheel X is free to revolve and the wheel Y is held
by the stop d consequently the wheel Y-having straight ribs the plunger moves in:
a direct line.
The action of the whole apparatus is as follows:—
The commutator e is divided in such a manner that electrical connection is made.
between the brushes 1-2 or 1-3, in the former case the coils B, B', and in the
latter case B, B1, are excited to draw the plunger back and forth. The com-
mutator e is rotated by any suitable means, say, the dynamo shaft from whence the
electro motive force is derived.
The dynamo shaft f is hollow at one end and into this end is inserted a
nozzle at the end of the pipe carrying the blast. The dynamo shaft f is.
provided with slots h, h, just between the segments of the commutator e and in
line with the brushes 2 and 3 as the breaking of the current and consequently
the sparking occurs where these slots are, the sparks are always met by the air
blast and extinguished.
Having now particularly described and ascertained the nature of this inven-.
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In an apparatus for rock drilling and like purposes, the combination of

page_text: :
appliances shown at Figure 1 of the drawings in which the tool is withdrawn after
each blow by the combined magnetic attraction of an outer electro-magnet and an
internal magnetic field as described, the blow of the tool being accomplished under
the action of a spring enclosed within the tool holder as set forth.
2. The arrangement of appliances shown at Figure 2 whereby the to and fro
motions of the tool are accomplished by the combined internal magnetic attraction
and an internal magnetic field as set forth.
Dated this 4th dow of Anril 1000
:
H. GARDNER,
166, Fleet Street, London, Agent for the said W. A'C. G. Birkin.