An Improvement in Percussion Rock Drills.
Year: 1896

page_text: Date of Application, 2nd Dec., 1896
Complete Specification Left, 29th July, 1897-Accepted, 4th Sept., 1897
An Improvement in Percussion Rock Drills.
I, JOHN SOLOMON VIVIAN BICKFORD, of Tredouvra, Falmouth, in the County of
Cornwall, Engineer, do hereby declare the nature of this invention to be
follows:-
My invention relates to percussion rock drills which are worked by fluid pressure
acting on a piston or plunger which it causes to reciprocate striking the head of a
drill or a distance piece interposed between the head and the stem of the piston
or plunger. I provide a long clamp or a pair of readily separable clamps by
which I firmly hold the stem of the drill, and I attach the clamp or clamps by
a pair of side bars to the cylinder of the drill, introducing in any convenient
part of each side bar a stiff spring which may be formed by a U bend of the side bar
itself. Each clamp is made in such a way that it can be put on the drill stem
sideways so that it is not necessary to pass the end of the stem, which may be
more or less upset, through any hole of the clamp.
The cylinder being held and turned by suitable handles, advances with the drill
as the hole becomes deepened, and its distance from the clamps being constant, the
blow remains practically the same during all the working of the drill.
Dated this 2nd day of December 1896.
ABEL & IMRAY,
Agents for the Applicant.
I, JOHN SOLOMON VIVIAN BICKFORD, of Tredouvra, Falmouth, in the County of
Cornwall, 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 percussion rock drills which are worked by fluid pressure
acting on a piston or plunger which it causes to reciprocate striking the head of a
drill or a distance piece interposed between the head and the stem of the piston or
plunger. I mount the drill as I shall describe referring to the accompanying
drawings.
Fig. 1 is a front view and Fig. 2 is a side view of the drill and its mounting
according to my invention. Fig. 3 is a plan and Fig. 4 is a side view of one of the
clamps shewn to an enlarged scale.
I provide a pair of readily separable clamps A by which I firmly hold the stem B of
the drill and I attach the clamps by a pair of side bars D to the cylinder C of the

page_text: drill, introducing a distance piece E between the end of the stem D and the
striker F.
Each clar p A is made with an open gab so that it can be put on the drill
stem sideways without having to pass the end of the stem, which may be more
or less upset, through any hole of the clamp. To one limb is jointed a hinge
bolt G which can be turned into a slit of the other limb, and then on screwing
up the nut the drill stem is held fast in the clamp. Instead of two separate
clamps, one long clamp might be employed. The clamp bas at each side a
projecting stud a which enters a slot in the side bar D. The slot is longer than the
stud so as to allow a little play when the drill is struck.
It is of advantage to give the frame certain elasticity. This may be done by
bending the side bars D as indicated by the dotted lines d.
The cylinder C being held and turned by suitable handles, advances along with
the drill as the hole becomes deepened, and its distance from the clamps being
constant, the blow remains practically the same during all the working of the
drill.
Having now particularly described and ascertained the nature of this invention
and in what manner the saine is to be performed, I declare that what I
claim is :-
A mounting for a percussion drill constructed and operating substantially as
described with reference to the drawings.
ABEL & IMRAY,
Agents for the Applicant.