Improvements in Percussive Rock Drills.
Year: 1889

page_text: Date of Application, 2nd Mar., 1889
Complete Specification Left, 1st Nov., 1889-Accepted, 14th Dec., 1889
PROVISIONAL SPECIFICATION.
Improvements in Percussive Rock Drills.
We, ALBERT WILLIAMS DAW and ZACHARIAS WILLIAMS DAW, of Laurvig, in the
Kingdom of Norway, Mining Engineers, do hereby declare the nature of this
invention to be as follows:—
Our invention relates, 1st, to improvements in the class of percussive rock drills
described in the specification of our prior patent No. 10738, dated 4th August 1887,
and consists in an improved arrangement of the passages formed in the piston rod
for the purpose of actuating the valve of the drill cylinder; 2nd to an improved
arrangement of parts enabling the same machine to be fitted to different sized
saddles according to the length of feed desired; and, 3rd, to an improved feed for
advancing the drill along the saddle. The two last named improvements are
applicable to percussive rock drills generally.
In carrying out the first improvement we construct the passages in the piston
rod of such length that when the piston is near the end of its stroke in either
direction, the end of the passage at one end of the piston rod comes outside the
gland through which such rod works, while the other end of such passage is
opposite the passage formed through the gland and leading to the opposite end of
the valve cylinder, so that such end of the valve cylinder will be directly open to
exhaust to the atmosphere, at the time that compressed air or steam is admitted
to the other end of such valve cylinder in order to reverse the valve. This action
occurs at each end of the piston stroke, thus rendering the reversal of the valve
certain, by enabling any accumulation of the motive fluid which may take place at
one end of the valve cylinder to be exhausted into the atmosphere during the action
of reversing the valve.
Any suitable number of openings may be made from the ends of the passages to
the outer surface of the piston rod.
Our second and third improvements which are applicable to percussive rock drills=
generally consist in a novel construction of parts for effecting the automatic feed or
advance of the machine along the saddle as the hole is bored by the drill, and which
enables the same machine to be mounted on different sized saddles according to the
length of feed required.
The saddle consists of a bed of segmental section and having at its centre the
saddle arm by which it is connected to a carriage or column, while at each end is a
vertical plate. These two plates are connected together by longitudinal bars at each
side with which four arms projecting down from the drill casing engage, so that the
bars serve to guide the machine in its movement in relation to the saddle. The feed
screw is arranged between the guide bars and is provided with a crank handle for
effecting the return movement of the machine in the usual manner, after it has been
automatically fed forward to the full extent on the saddle. A spring catch is
arranged to prevent the feed screw rotating when the machine is being fed forward
automatically.
The feed nut is mounted on the feed screw and is carried in bearings forming part
of or secured to the drill casing in which such nut can rotate.
By this arrangement as the guide bars and feed screw are carried by the saddle,
while the arms to engage the guide bars and the feed nut are carried by the machine,
the latter may be mounted on any saddle, the bars and feed screw of which may be
of any desired length, but of a diameter and relative disposition suitable to engage
the guide arms and feed nut on the machine.
On the end of the feed nut a ratchet wheel is formed with ratchet teeth on its end
face, such teeth being arranged in a circular path.

page_text: A puppet-head or slide has one or more arms working through guide holes in the
body of the drill casing, the end of such arm or arms outside the casing being
surrounded by springs tending to force then outwards. The puppet-head or slide
has a part within the casing which lies in the direct path of travel of the drill piston
as it reciprocates, and on such piston an inclined lifter is formed or arranged, the
inclined surface acting upon the puppet-head and forcing same inwards during the
backward stroke of the drill. In order to permit the drill to be rotated after each
stroke, the connection between its piston and the inclined lifter may be in the form of
a swivel, or of a ball, or other suitable joint. To the part of the puppet-head below
the drill spindle is pivotted a link the end of which is in the form of a pawl and
shaped to engage the ratchet teeth on the face of the wheel forming part of the feed
The pivot of the link extends through the puppet-head and is surrounded by
a spring tending to force the pawl towards the ratchet teeth. Instead of the spring
being applied to the pivot of the link, the part thereof which forms the pawl may be
capable of sliding through the body of the link, and the spring arranged to force
such sliding part into contact with the ratchet teeth of the feed nut.
screw.
When in action the lifter moves with the drill spindle piston and accordingly raises
and lowers the puppet-bead, the action of the springs surrounding the arm or arms
of the latter ensuring the return movement of the puppet-head during the forward
stroke of the drill. The reciprocating motion thus imparted by the drill spindle to
the puppet-head is communicated to the link pawl which moreover acquires a lateral
and an angular motion in the performance of its functions, the former by the detent
of the link sliding over the inclined planes of the ratchet wheel of the feed nut, and
the latter by its being compelled to move in the circular path of the ratchet teeth; the
pivotal connection between the link and the puppet-head, together with the spring
acting upon such pivot (or upon the sliding part working through the body of the
link) permits these movements. The teeth of the ratchet wheel are semicircular, and
the length between them is so proportioned as not to allow the pawl to engage the
next tooth before the piston has made its full forward stroke; when this takes place
the pawl is forced into engagement with one of such notches or teeth by the spring
acting upon its pivot, (or upon the sliding part), and owing to the forward movement
of the pawl which follows, a pariial rotation of the ratchet wheel is effected on the
return or back stroke of the piston, such movement being transmitted to the feed nut
which turns on the feed screw and thus forces the machine forward on the saddle. In
consequence of this advance the next stroke of the piston will not be a full stroke, and
will not be a full stroke again until the length of the forward movement has been
bored by the drill, and until this takes place the pawl cannot enter a fresh notch or
tooth of the ratchet wheel. Immediately that the piston regains its full stroke the
pawl will engage a fresh notch or tooth and a further advance will be given to the
machine.
The inclined lifter cannot rotate with the drill spindle, as it is always in contact
with the rubbing surface of the puppet-head, the pressure by which the surfaces are
kept together by the springs surrounding the arms of the puppet-head being more than
sufficient to counterbalance the friction of the swivel attachment between the lifter
and the drill spindle; moreover such rotation is entirely prevented by the lifter moving
against the guide arms of the puppet-head. The lifter is further preferably provided
with guide surfaces or webs engaging suitable grooves, which serve to guide it in its
o and fro movement with the piston rod.
If desired the lifter may be in the form of a conical bar, its action being precisely
similar to that of the inclined lifter described, but in this case no swivel attachment
or ball joint is required between it and the drill spindle, as the conical form will
permit of the bar rotating with the drill spindle.
The feed gear can be adapted to either end of the drill.

page_text: Fig. 13 a transverse section of saddle on line 1, J.
Fig. 14 a transverse section of a modified form of feed gear
Fig. 15 a modified form of the lifter for actuating the automatic feed gear.
Fig. 16 a horizontal section of the puppet-head of the feed gear shown in Fig. 14,
and
Fig. 17 a horizontal section of a modified form of the link and pawl of such
puppet-head.
In carrying out the first improvement referred to we construct the passages M, M2,
in the piston rod R, R1, R2, of such length that when the piston P is near the end of
its backward stroke, one end of the passage M2 comes outside the stuffing box
through which such rod works, into the upper part of the cylinder, which is open to
the atmosphere, while the other end of such passage M2 is opposite the passage M³
formed in the stuffing box, and which (as described in our Patent above referred to)
leads to the end of the valve cylinder C₁ so that such end of the valve cylinder
will be directly open to exhaust to the atmosphere, at the time that compressed
air or steam is admitted to the other end C2 of such valve cylinder in order to
reverse the valve V. Similarly when the piston P is near the end of its forward
stroke, one end of passage M is outside the stuffing box, or open to the auno-
sphere, while its other end is opposite the passage M in the stuffing box and
leading to the end of valve cylinder, so that such end will be directly
open to exhaust to the atmosphere at the time that compressed air or steam is
being admitted to the other end of valve cylinder in order to reverse the
valve V. The action described occurs at each end of the piston stroke thus
rendering the reversal of the valve V certain, by enabling any accumulation of
the motive fluid which may take place at one end of the valve cylinder, to be
exhausted into the atmosphere during the action of reversing the valve V.

page_text: Any suitable number of openings 01 may be made from the ends of the
passages M, M², to the outer surface of the piston rod.
When the valve pistons P1, P2, which are connected together by the stem D', and
between which the valve V is arranged, are caused to move in their cylinders (", C²,
they will carry valve V with them and so control the movement of piston P in
cylinder C by governing the supply and exhaust passages I, I, E, thereof.
Our second and third improvements which are applicable to percussive rock drills
generally consist in a novel construction of parts for effecting the automatic feed
or advance of the machine along the saddle as the hole is bored by the drill, and
which enables the same machine to be mounted on different sized saddles according
to the length of feed required.
The saddle consists of a bed D of segmental section and having at its centre the
saddle arm D2 by which it is connected to a carriage or column, while at each
end is a vertical plate D³. These two plates D³ are connected together by two
longitudinal bars Q₁, one at each side, with which four arms Q3, projecting down
from the drill casing B, engage, so that the bars serve to guide the machine in
its movement in relation to the saddle. The feed screw Qis arranged between the
guide bars Q1, and is provided with a crank handle for effecting the return move-
ment of the machine, in the usual manner, after it has been automatically fed forward
to the full extent on the saddle. A spring catch or pin T2 is arranged to fit in a
suitable hole or recess in the screw so as to prevent it rotating when the machine is
being fed forward automatically.
The feed nut N is mounted on the feed screw Q and is carried in bearings forming
part of or secured to the drill casing B in which such nut can rotate.
By this arrangement as the guide bars Q', and feed screw Q are carried by the
saddle, while the arms Q2 to engage the guide bars, and the feed nut N, are carried
by the machine, the latter may be mounted on any saddle the bars and feed screw of
which may be of any desired length but of a diameter and relative disposition
suitable to engage the guide arms Q and feed nut N on the machine.
On the end of the feed nut. Na ratchet wheel Z is attached or formed and is pro-
vided with ratchet teeth.
A puppet-head or slide P³ has two arms J, J', working through guide holes B² in,
or bearings outside, the body of the drill casing B, one of such arms having an
opening S¹ to receive a spring G1, which is fitted to react against an arm H fitting
therein, and either projecting from the drill casing, or the cap used to cover the
bearing. The spring G tends to force the puppet-head or slide against an inclined
lifter T. The puppet-head or slide P³ has a part K, which lies in the direct path of
travel of the drill piston rod R1, R2, as it reciprocates, and on such piston rod R', R²,
the inclined lifter L is formed or arranged, the inclined surface acting upon the
part K of the puppet-head and forcing sune outwards, during the backward stroke
of the drill. In order to permit the drill to be rotated after each stroke, the con-
nection between its piston rod R2 and the inclined lifter L, may be in the form of the
swivel joint D, C, or of a ball or other suitable joint.
In the construction shown in Figs. 14 and 17 the part of the puppet-head below
the lifter L has pivolted thereto a link W, the end of which is in the form of a
pawl and shaped to engage the ratchet teeth which in this case are formed on the
end face of the wheel Z2 forming part of the feed nut N. The pivot W of the link W
extends through the puppet-head, and is surrounded by a spring G² tending to force
the pawl H towards or against the ratchet teeth. Instead of the spring G2 being
applied to the pivot W of the link, (as shown in Fig. 17) the part thereof which
forms the pawl H₁ may be capable of sliding through the body of the link W, and
the spring G2 arranged to force such sliding part H' into contact with the ratchet
teeth of the feed nut, as shown in Fig. 16.
When in action the lifter L moves with the drill spindle and piston and accordingly
raises and lowers the puppet-head P³, the action of the spring in the interior of
arm J thereof reaching against projecting arm H ensuring the return movement of
the puppet-head during the forward stroke of the drill. The reciprocating motion

page_text: thus imparted by the drill spindle to the puppet-head P³ is communicated to the link
pawl W, which moreover acquires a lateral and an angular motion in the performance
of its functions, the former by the detent of the link sliding over the inclined planes
of the teeth of the ratchet wheel Z2 of the feed nut N, and the latter by its being
compelled to move in the circular path of the ratchet teeth; the pivotted connection
between the link W and the puppet-head P³, together with the spring acting upon
such pivot (or upon the sliding part working through the body of the link) permits
these movements. The teeth of the ratchet wheel are semicircular, and the length
between them is so proportioned as not to allow the pawl H¹ to engage the next tooth
before the piston has made its full forward stroke; when this takes place the pawl H'
is forced into engagement with one of such notches or teeth by the spring G2 acting
upon its pivot (or upon the sliding part), and owing to the forward movement of the
pawl which follows, a partial rotation of the ratchet wheel Z2 is effected on the return
or back stroke of the piston P, such movement being transmitted to the feed nut N
which turns on the feed screw Qand thus forces the machine forward on the saddle.
In consequence of this advance the next stroke of the piston P will not be a full
stroke, and will not be a full stroke again until the length of the forward movement
has been bored by the drill, and until this takes place the pawl cannot enter a fresh
notch or tooth of the ratchet wheel. Immediately that the piston regains its full
stroke the pawl will engage a fresh notch or tooth and a further advance will be given
to the machine.
The inclined lifter L cannot rotate with the drill spindle R1, R2, as it is always in
contact with the rubbing surface of the puppet-head P³, the pressure by which the
surfaces are kept together by the spring G₁ in the interior of arm J of puppet-head P³
being more than sufficient to counterbalance the friction of the swivel attach-
ment D, C³, between the lifter L and the drill spindle R', R2; moreover such
rotation is entirely prevented by causing the lifter to work through the puppet-
head P3 as shown. The lifter L is further preferably provided with guide surfaces
or webs engaging suitable grooves, which serve to guide it in its to and fro move-
ment with the piston rod.
If desired the lifter L may be in the form of a conical bar (as shown in Fig. 15)
its action being precisely similar to that of the inclined lifter described, but in this
case no swivel attachment or ball joint is required between it and the drill spindle,
as the conical form will permit of the bar rotating with the drill spindle.
In the modified construction of feed gear shown in Figs. 1 and 5 the arm J' of the
puppet-head P3 carries the pawl H in the guide socket S² wherein the spring G² is
fitted to react upon the pawl H', so as to force it in contact with the inclined planes
of, and (when the drill piston has made its full stroke), to engage the teeth of the
ratchet wheel Z secured to feed nut N mounted on the feed screw Q, the teeth of such
ratchet wheel Z being in this case formed on the periphery thereof, instead of on its
end face as in the arrangement previously described. The other arm J of the puppet-
head or slide P³ has an opening S¹ in its outer end to receive the spring G', and the
arm H mounted on the casing B of the drill, or forming part of the cap of
bearing B², enters the opening S¹ so as to cause the reaction of spring G' on the
puppet-head P³, as in the arrangement already described. When lifter L moves
with the drill piston P during its back stroke its inclined surface forces the puppet-
head P³ against the action of the spring G¹, and the pawl H¹ gearing with ratchet
wheel Z rotates same so as to effect the feed. During the forward stroke of the drill,
spring G forces the puppet-head P³ in the opposite direction causing the pawl H¹ to
slip over the teeth of ratchet wheel Z and to engage a fresh tooth thereof, when the
piston again attains its full stroke in the same manner as before described.
The feed gear can be adapted to either end of the drill. In applying the gear to
the forward end of the drill a collar will be secured to the drill piston rod so that
such collar will follow this latter in its to and fro movements, while permitting
the piston rod to turn within it, and to this collar the lifter L will be secured,
and by its to and fro movements will actuate the feed gear in the manner above
escribed

page_text: A circular
The 4th improvement consists in the method of providing a bearing for the end
of the rifled bush Y of the rotating gear in the block or bearing F", (see Fig. 1),
and causing such block to serve as a guide for the piston rod and the inclined
lifter L. The bearing or block F in its longitudinal section has the form of a cone
except at each end, where it is provided with a circular plate B¹.
opening passes through the contre of block F' to allow of the travel of piston rod R
and lifter L for which it acts as a guide. The plates B₁ at each end are accurately
turned on their circular edge to fit compactly against the interior of drill casing, and
the whole is fixed in the position shown in Fig. 1, by the screw bolts E¹ shown in
Fig. 5, one half section of each of which is in the block and the other half in casing
of drill.
The forward end of the rifled bush Y for rotating the drill at each backward stroke
of the piston, has its bearings in the rear end of the block or bearing F¹.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. In a rock drill the piston rod of which is provided with two separate passages
for controlling the supply and exhaust of compressed air or steam to and from the
opposite ends of a cylinder in which the valve for reversing the motion of the main
piston of the drill can reciprocate, constructing such passages of such a length as to
ensure one end of the valve cylinder being open to exhaust to the atmosphere while
the compressed air or steam is being admitted to the opposite end of such valve
cylinder, for the purpose of reversing the valve, all substantially as specified.
2. The combination in a rock drill of a saddle carrying the guide bars and feed
screw, with a nut mounted to revolve in the casing of the drill and engaging the feed
screw while arms projecting from such casing engage the guide bars, all substantially
as and for the purpose specified.
3. The employment of a lifter L secured to the drill piston rod so that it recipro-
cates therewith, such lifter having an inclined surface for actuating the feed gear, all
substantially as specified.
4. The combination with the drill piston rod of a lifter L having an inclined
surface which acts upon a puppet-head or slide P³ mounted in the drill casing and
acted upon by a spring or springs, such puppet-head or slide carrying a pawl engaging
the teeth of the feed nut N which is mounted so as to be capable of revolving in the
drill casing, substantially as specified.
5. The bearing or block F serving to receive one end of the rifled bush Y of the
rotating gear and also as a guide for the piston rod and the lifter L for actuating the
feed gear, substantially as specified.
6. The general construction, arrangement and combination of parts constituting
the improved rock drill, all operating substantially as and for the purposes specified.
Dated this 23rd day of August 1889.
ALLISON BROS.,
Agents for the Applicants.