Improvements in Rock Drills.
Year: 1892

page_text: Date of Application, 14th May, 1892
Complete Specification Left, 11th Feb., 1893-Accepted, 11th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in Rock Drills.
I CHARLES WILLIAM BURTON, of Nogent par Creil (Oise) France Engineer
do hereby declare the nature of this invention to be as follows:-
My invention relates to a hand operated percussive rock drill and it consists
essentially in the combination of mechanism for rotating the boring tool, of
automatic feed mechanism therefor and of adjusting mechanism for regulating the
force of the blow.
My invention is illustrated in the accompanying drawings wherein
Figure 1 represents a longitudinal section and Figure 2 a plan of the rock drill.
Figures 3, 4 and 5 illustrate the automatic feed mechanism and Figures 6, 7,8
and 9 illustrate the tool rotating mechanism separately.
The saine letters of reference denote like parts in the several figures.
A Figure 1 is a guide in which slides a frame formed of two slotted side
bars B, B1 united by crossheads D, E and serving as guides. The percussive part
of the tool comprises a rod C C¹ which carries the boring tool and is attached to a
sliding crosshead G (Figures 1 and 2) which works in the guide slots of the side
bars B, B and upon which act the cams F. The percussive action is produced by
a spiral spring H confined between the sliding crosshead G and an abutment I
which is adjustable by a nut J to regulate the initial tension of the spring in order
to vary the force of the blow according to the nature of the work and the elasticity
or strength of the spring. The spring is further compressed by the motion of the
crosshead G produced by the cams on the shaft upon whose ends are keyed
two fly wheels with winch handles.
The rotary motion of the boring tool is imparted by means of spiral ratchet teeth
on the part C of the striker rod, with which engages a pawl K (Figure 6) pivoted
on a cross bar L fixed to the side bars B, B¹, the part C of said rod being formed
with a longitudinal keyway M' and sliding through and engaging with a ratchet
wheel M mounted within the cross head D and engaged by a pawl N (Figures 6, 7,
8 and 9).
The tool is rotated during the whole of the backward stroke by the pawl K
acting on a tooth of the spiral ratchet C, the ratchet wheel M slipping, whilst on
the forward stroke the pawl K slips one tooth, the ratchet wheel M being then
retained by the pawl N, the rod C being pivoted in the sliding crosshead G so as
to permit of its rotation.
The automatic feed motion (Figures 3, 4 and 5) whereby the operative parts of
the tool are advanced along the guide frame A as the bore hole deepens, comprises
the feed screw O which is held stationary during the working in a bracket P
carried by the guide frame A. This screw is situated in the longitudinal axis of
the tool and traverses a nut R mounted to turn between abutments in the rear
crosshead E and peripherally ratchet toothed, with which engages a pawl S pivoted.
between two collars turning loose upon the nut by a lever T pivoted to one of the
side bars and operated by the cams F1 upon the shaft F, a check pawl U preventing
the nut turning backwards during the return stroke of the feed pawl S.
The operation of the automatic feed motion is determined by the sliding cross-
head G during its forward movement, acting when it has exceeded a certain
length of stroke upon the part G¹ of lever T and moving the latter so as to
cause the pawl S to slip over the ratchet teeth R and bring the end G" of the
lever within range of the cams F" which at the proper moment return lever T
to its former position, the engagement of the pawl $ with the ratchet R pro-
ducing the feed movement. The return motion is effected by unlocking the

page_text: screw and turning it by hand so as to traverse the nut R and attached frame
backwards along it.
Dated May 14th 1892.
By A. M. & Wm. Clark,
DORIU
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Rock Drills.
I CHARLES WILLIAM BURTON of Nogent par Creil (Oise) France, 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 a hand operated percussive rock drill and it consists
essentially in the combination of mechanism for rotating the boring tool, of auto-
matic feed mechanism for regulating the force of the blow. My invention is
illustrated in the drawings accompanying my Provisional Specification, wherein
Figure 1 represents a longitudinal section and Figure 2 a plan of the rock
drill.
Figures 3, 4, and 5 illustrate the automatic feed mechanism, and Figures 6,
7, 8, and 9 illustrate the tool rotating mechanism separately.
The same letters of reference denote like parts in the several figures.
A Figure 1 is a guide in which slides a frame formed of two slotted side bars BB'
united at their extremities by crossheads DE serving respectively as guides for
the boring tool and feed screw. The percussive part of the apparatus comprises a
rod CC which carries the boring tool and is attached to and journaled in a sliding
crosshead G (Figures 1 and 2) which works in the longitudinal guide slots of the
side bars B B and upon which act cams F1 carried by a shaft F upon whose
extremities fly wheels provided with winch handles are mounted. The percussive
action is produced by a spiral spring H confined between the sliding crosshead G
and an abutment I which is adjustable by a nut J to regulate the initial tension of
the spring to compensate for loss of elasticity after prolonged use or in order to
vary the force of the blow according to the nature of the work.
The rotary motion of the boring tool is imparted by means of ratchet teeth in
the form of a spiral of very long pitch on the part C of the striker rod, with which
engages a pawl K (Figure 6) pivoted on a cross bar L fixed to the side bars B B',
the part C of said rod C sliding through and engaging by a key and longitudinal
key way M with a ratchet wheel M mounted within the crosshead D and engaged
by a pawl N (Figures 7, 8, and 9).
The tool is rotated during the whole of the backward stroke by the pawl K
acting on a tooth of the spiral ratchet C, the ratchet wheel M slipping beneath its
pawl whilst on the forward stroke the pawl K slips over one tooth of the spiral
ratchet C and the ratchet wheel M being engaged by the pawl N, the rod C is
prevented from rotating.
The automatic feed motion (Figures 3, 4 and 5) whereby the operative parts of
the tool are advanced along the guide frame A as the bore hole deepens, comprises
the feed screw O which is held stationary during the working in a bracket P carried
by the guide frame A. This screw is situated in the longitudinal axis of the tool
and traverses a nut mounted to turn between abutments in the rear crosshead E
and provided with peripheral ratchet teeth, with which engages a pawl S pivoted
between two collars which turn loose upon the nut. A lever T, pivoted to one of
the side bars and operated by the cams F upon the shaft F acts on the collars
carrying the pawl $ and advances the nut R at each half revolution of shaft F, a
check pawl U preventing the nut turning backwards during the return stroke of
the feed pawl S.

page_text: The operation of the automatic feed motion is determined by the sliding cross-
head G during its forward movement, acting when it has exceeded a certain length
of stroke upon the part G' (Figure 4) of lever T and moving the latter so as to
cause the pawl S to slip over the ratchet teeth R and bring the end G¹¹ of the
lever within range of one of the cams F" which at the proper moment returns
lever T to its former position, the engagement of the pawl S with the ratchet nut R
producing the feed movement of the nut and with it of the frame B along the
screw O. The return motion is effected by unlocking the screw O. The return
motion is effected by unlocking the screw O and turning it by hand so as to traverse
the nut R and attached frame backwards along it.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what 1
claim is-
1. The general combination and arrangement of the hereindescribed hand
operated rock drill having the feed screw situated in the longitudinal axis of the
boring tool as described.
2. In a hand operated rock drill, the combination with the striker rod of the long
spirally toothed part C and its pawl K and of the pawl and ratchet gear M Ñ
whereby the rotation of the boring tool is effected in the manner described.
3. In a hand operated rock drill, the combination with the other mechanism
described of the feed screw O and the automatic feed mechanism arranged and
operating substantially as described.
4. In a hand operated rock drill, the combination with the sliding tool holder
and with the mechanism for producing the automatic rotation and feed motion of
the boring tool as described, of the spring H, crosshead G, cams F¹, shaft F,
abutment I, aud nut J, whereby to regulate the initial tension of the spring as
required, substantially as hereinbefore described and illustrated in the drawings.
IJALEN EOIs Irn nav OL Kebruary IXUR
JALAN LAIS
C. W. BURTON.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.