Year: 1888

page_text: Date of Application, 27th Oct., 1888"
Specification Accepted, 30th Nov., 1888
We, GEORGE MOLE, Implement Maker, Haswell, and JOSEPH PEARSON, Quarry
Agent, Tuthill, Haswell, both near Sunderland, in the county of Durham, do hereby
declare the nature of this invention and in what manner the same is to. he per-
formed, to be particularly described and ascertained in and by the following
statement:
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This invention relates to an improved percussive hand drilling machine and is
especially adapted for use in quarry work. Hitherto it has been the practice in
drilling holes preparatory to blasting in quarry work to use a tool known as a
'jumper which consists of an iron bar usually round with a drill bit formed on one
end of it and a hole is forined by "jumping" the bar up and down and at the same
time gradually turning it round in the hole. This "jumping" has been effected by
manual power and in the following way. One man holds the bar in his two hands
vertically for a vertical hole and he gives the bar a succession of lifts each time
bringing it down again with considerable force and frequently two men are employed
on one jumper bar for this purpose. It will be seen that very considerable exertion
is thus exercised in lifting the heavy jumper bar preparatory to making each
percussive down stroke and it. with a view to diminish this negative energy that we
have devised the following means which form the subject matter of our invention and
which it is now our intention to fully describe having reference to the accompanying
drawings in which Fig. 1 shows an end elevation Fig. 2 a plan and Fig. 3 a side
elevation of our improved percussive hand drilling machine. Fig. 4 is a section on
liness in Fig. 2 showing constructive detail and Figs. 567 and 8 show side and end
elevations plan and section respectively of details or modifications of our invention to
be more particularly hereinafter referred to and throughout this description similar
letters of reference in the specification and in the drawings designate corresponding
parts.
a is a triangular iron frame furnished at the corners with holes through which
the levelling pins e pass the adjustment of the pins being effected by set-bolts d in the
usual way. Inside the frame a we arrange a subsidiary frame a which may be
rivetted to the external frame as shown in the drawings. a² a² are vertical bars of

page_text: iron about two and a half to three feet long pivotted at their bases to the frame a¹ and
these bars are further connected to one another by the distance pieces a³ a³ through
the holes at a in which the jumper bar a passes. The ends of the distance pieces
may be furnished with screwed,gudgeons which pass through the verticals a² a² and are
secured to them by nuts as shown in the drawings. Further we provide the distance
pieces a³ ³ with hinged sides one end of such side being hinged as at a and secured
when shut by a stud or set-pin a' this arrangement being necessary in order to readily
ship or unship the jumper laterally from its position in the guides or distance
pieces a a³ for it is evident that unless the holes at a were made very large the bitted
end as of the jumper would not pass through such holes and if the holes were large
enough to allow this they would be too large for their designed purpose viz. to act as guides
to the jumper.. Immediately above the lower distance piece a³ we place a power
spring a arranged so as to encircle or embrace the jumper and we compress this
spring against the upper surface of the lower distance piece by means of the hinged
clamp which is tightly secured against the jumper to prevent its sliding thereon
by the bolt a The effect of thus compressing the spring and making its upper
end abut against the clamp a secured as described to the jumper bar. a is of course
to lift the latter and hold it in suspension the height to which it is lifted being pro-
portional to the weight of the jumper and the resilience of the spring which as stated
can be regulated at will by altering the position of the clamp a¹.
The operation of our invention is thus as follows: -The site for the required hole
having been selected the jumper and frame are arranged immediately over the same
any inequalities in the ground level being met by a corresponding adjustment of the
levelling pins e so as to set the frame a level and the jumper a plumb. The operator
then takes hold of the upper end of the jumper bar, and slightly lifts it and then
forces it down again thus making the first stroke of the jumper to form the hole. The
spring a becoming further compressed by the downstroke instantly forces the jumper
up again to the required height and the operator instantly forces. it down again to make
the next downstroke and thus the operation is repeated. In practice therefore the
operator is relieved of the exertion of lifting the jumper at each stroke as this work
is performed by the spring the reaction of which is so rapid as to result in a very
greatly increased rate of strokes of the jumper per unit of time and this increase in
speed is found to very much more than compensate for the loss of the effective blow
during the downstroke caused by the counter pressure of the spring during the latter
operation.
-
In order to provide for other than vertical downward holes we arrange the
verticals a² a so as to radiate from their centre of motion at a as shown by the
dotted lines in Fig. 3 and we provide sectors a¹³ a¹³ for the adjustment of the verticals
to the requisite angle of inclination arranged within the subsidiary frame a¹ as shown
in the drawings. By the simple withdrawal of the bolts at the verticals a² a² can be
thus set to any ordinary angle of inclination for drilling inclined holes the verticals
guide pieces and jumper bar being thus held securely in position at the required
angle by means of the bolts a which are arranged to be passed through both the
-verticals and the fixed sectors for the purpose described.
By a modification of the above arrangement instead of one spring embracing the
jumper we may employ two three four or more springs as found desirable and the
springs may be arranged outside the jumper either as compression or tension springs
during the downstroke. In Figs. 5 6 7 and 8 an arrangement is shown adapted for
four springs represented by thick dotted lines nnnn. The lower ends of these
springs are connected to the plate n' shown in detail in Figs. 7 and 8 which is
furnished with side gudgeons n² which serve to guide the plate in a vertical plane in
the slotted side plates n³. The plate a¹ is also provided with a slot for the lateral
adjustment of the jumper the slot opening being controlled by a hinged plate no
arranged to open and shut as desired in the manner explained in reference to the
hinged distance pieces a³ in Figs. 1 2 and 3. The top ends of the springs n nnn are
attached in any convenient manner to the top distance piece n and the position of the
jumper n in relation to the plate n' is regulated by means of the clamp n which

page_text: as shown in the drawings is connected to the jumper immediately above the lower
plate n'. The downstroke of the jumper is in this case made against the tensional
resistance of the springs nn nn the upstroke being automatically effected by the
compressive resilience of the same.
Having now particularly described and ascertained the nature of this our
said invention and in what manner the same is to be performed we declare that
what we claim is :-
(1.) In percussive hand drilling machines the combination with the jumper or drill
of a power spring or springs arranged to automatically perform the up or return
stroke of the jumper or drill substantially as herein set forth.
Dal 1 och
1000
A. CRAWHALL CHAPMAN,
2, St. Nicholas' Buildings, Newcastle-on-Tyne,
Patent Agent for Applicants.
A. CRAWHALL CHAPMAN,
2, St. Nicholas' Buildings, Newcastle-on-Tyne,
Patent Agent for Applicants.