Improvements relating to Rock-drilling Machines.
Year: 1891

page_text: Date of Application, 30th June, 1891
Complete Specification Left, 9th Mar.; 1892-Accepted, 9th Apr., 1892
[Communicated from abroad by JAMES MCCULLOCH, of Minas de Rio Tinto,
Huelva, in the Kingdom of Spain, Engineer.]
Improvements relating to Rock-drilling Machines.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
My invention relates to rock-drilling machines and is designed to provide
improved means for partially rotating the drill about its axis in its backward or
return stroke or movement.
According to my said invention, I provide, as hereinafter mentioned, for
permitting the twist-bar to freely rotate about its axis during the forward or
operative stroke or movement of the drill, and for firmly holding the said twist-
bar and restraining it from rotation during the return or non-operative stroke or
movement of the drill, or vice versa if desired.
The devices hitherto employed for this purpose, are liable to injury (such as
the breakage of ratchet-teeth or of the twist-bar) when subjected to certain stresses
which are apt to be brought upon them in the working of the machine.
By my improvements, however, although I employ two toothed or ratchet discs,
1 obviate the liability to breakage of the teeth thereof or of the twist-bar under
any stresses to which the rotating-gear may be subjected in the ordinary working
of the machine.
One of the said ratchet-discs of my rotating-gear is fixed upon the twist-bar so
that it will rotate therewith. The other ratchet-disc is preferably arranged within
a cover or casing firmly secured to the cover of the cylinder. This ratchet-disc is
restrained from rotation, but is free to be moved longitudinally or axially relatively
to the ratchet-disc on the twist-bar; for instance it is made with a square, hexagonal
or other suitably shaped boss or hub fitting into a correspondingly shaped hole in
a block or piece of india-rubber or other suitable elastic or spring material, which
block or piece is fitted to slide but is restrained from rotation in the said cover or
casing. The elastic material or spring around the boss or hub of the non-rotating
ratchet-disc, by yielding when any undue stress comes upon the said disc, obviates
the liability to breakage of the teeth of the said discs.
To provide for keeping the ratchet-discs in gear with each other, I combine,
with the non-rotating ratchet-disc, a valve or piston working in a cylindrical
chamber in the aforesaid cover or casing and acted upon by a spring, or by
compressed air, steam or other fluid admitted through a suitable aperture or port,
or both by a spring and by the fluid under pressure. By these means, the twist-
bar will, during the return or non-operative stroke of the drill, be restrained from
rotation by the non-rotating ratchet-disc; in the forward or operative stroke of the
drill, however, the ratchet-disc on the twist-bar will push the non-rotating ratchet-
disc backward and the said bar will turn about its axis, the non-rotating disc working
in and out of gear with the other disc.
I may, if desired, provide for the automatic movement of the non-rotating
ratchet-disc relatively to the ratchet-disc on the twist-bar for the purpose of putting
it into and out of gear therewith as required.
For instance provide for connecting the cylindrical chamber in which works
the aforesaid valve or piston, alternately with the supply pipe for the compressed
air or other fluid under pressure, and with the exhaust.
I fix in the aforesaid cover or casing, a rod or spindle which extends through

page_text: the aforesaid valve or piston and through the non-rotating ratchet-disc, and which
bears against the rear end of the twist-bar, thus keeping the said bar in its place,
and preventing the subjection of the said valve or piston and its spring to undue
stresses. The said rod or spindle is, if desired, made adjustable, and it may, if
found more convenient, extend partly into the ratchet-disc on the twist-bar.
Dated this 30th day of June 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements relating to Rock-drilling Machines.
1, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co. Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 rock-drilling machines and is designed to provide
improved means for holding or preventing the rotation of the twist bar during the
backward or return stroke or movement of the drill, and for releasing the said bar
during the forward or operative stroke of the drill, or vice versa if desired, the
object being as is well known to cause the drill to partially rotate about its axis
during either its forward or backward stroke. I prefer that the drill be thus
partially rotated during its backward stroke and not during its forward stroke as
then it is more likely to give a much more effective blow.
The devices hitherto employed for this purpose, are liable to injury, (such as
the breakage of ratchet teeth or of the twist bar) when subjected to certain stresses
which are apt to be brought upon them in the working of the machine.
By my improvements, however, although I employ two toothed or ratchet discs,
I obviate the liability to breakage of the teeth thereof or of the twist-bar under
"any stresses to which the rotating-gear may be subjected in the ordinary working
of the machine.
In the accompanying drawings
Figure 1 is a longitudinal central section of so much of a rock-drilling machine,
having one form of my improvement applied thereto, as is necessary to illustrate
my invention.
Figures 23 and 4 are transverse sections of Figure 1 taken respectively on the
lines x, x, x and x², a² of the said figure.
Figure 5 is a longitudinal central section of a portion of a rock drill showing a.
modification of my invention hereinafter described.
Figures 6 and 7 are transverse sections of Figure 5 taken respectively on the
lines yyyy of the said figure the internal parts being removed.
Figure 8 is a side elevation of one of the retaining discs and a part of the twist
bar shown in Figure 5.
Figure 9 is an end elevation of the same looking from the right of Figure 8.
Figure 10 is an end elevation looking from the left of Figure 8.
Figure 11 is a side clevation of another of the retaining discs shown in Figure 5.
Figures 12 and 13 are end elevations of the same looking from the right and
left respectively of Figure 11.
Figure 14 is an elevation of the cylinder of the rock drill on a reduced scale,
showing a passage for air leading from the front end of the cylinder to the rear of
the twist-bar retaining device.
Figure 15 is a longitudinal central section of a portion of a rock drill shewing
another modification of my invention.
Like letters of reference indicate corresponding parts throughout the drawings.
A is the cylinder cover in which is mounted so as to be free to rotate about its

page_text: axis the twist bar B. C is a disc screwed or otherwise fixed on the end of the
twist bar. The said disc C is provided with teeth C¹ on its outer face for a purpose
hereinafter specified. On the cover A I mount another cover or casing A¹, and
within a recess A' in the said cover or casing I arrange a second toothed disc D
in such a manner that while the said disc D is free to move longitudinally or
axially for a short distance within the cover A¹ it cannot rotate therein.
The
axial movement of the disc D is for the purpose of allowing its teeth D₁ to engage
and disengage with the teeth C¹ of the disc C.
In the construction shown in Figure 1 the disc D is inade with a square boss o
hub D fitting into a correspondingly shaped hole in a block or piece of india-
rubber E or other suitable elastic material which block or piece E is fitted to slide
but is restrained from rotation in the said cover or casing A. This is conveniently
effected by making the interior of the casing A square in cross section and forming
the elastic block E to fit the same. I have shown the discs C, D in Figure as
having ratchet teeth so that in this construction the disc C will only be prevented
from rotating in one direction, and will be free to rotate in the other direction by
sliding over the ratchet teeth and forcing back the disc D within the cover or
casing A. The elastic material E around the boss or hub of the non-rotating
disc D will yield when any undue stress comes upon the discs C, D, and will thus
obviate the liability to breakage of the teeth of the said discs.
To provide for keeping the ratchet discs in gear with each other, I provide as
follows that is to say, behind the disc D I arrange a piston F which works in a
cylindrical chamber F¹ formed in the cover or casing A' and is acted upon by a
spring For by compressed air, steam or other fluid admitted through a suitable
aperture or port F3 or both by the spring and by the fluid under pressure. The
operation of this device is as follows. The disc D is forced into gear with the
disc C by the pressure of the spring For of the fluid entering by the aperture F³
or both acting upon the piston and through the said piston on the elastic
material E. By this means the twist-bar will during the return or non-operative
stroke of the drill, be restrained from rotation. In the forward or operative stroke
of the drill, however, the ratchet-disc C on the twist-bar B will push the non-
rotating ratchet disc Ĺ backward and the said bar will turn about its axis, the non-.
rotating disc D working in and out of gear with the other disc.
I prefer to arrange the ratchet teeth as shown so that the discs will be locked
together as above described and prevented from rotation during the return or non-
operative stroke of the drill; if desired however I may employ discs having teeth
pointed in the reverse direction so as to lock the twist bar when the drill is per-
forming its forward or operative stroke.
In order to maintain the twist bar in its proper place and to prevent the sub-
jection of the piston F and its spring F to undue stresses, I fix in the cover or
casing A a rod or spindle G which extends through the piston F and through the
non-rotating ratchet disc D and which bears against the rear end of the twist-bar.
I have shown the said rod or spindle G as being screwed into the cover A' and
further secured by a lock nut G This method of fixing permits of adjustment.
I have also shown the rod partly extended into the ratchet disc C on the twist-
bar to give additional lateral support to the said rod.
According to a modification of my invention I provide for the automatic move-
ment of the non-rotating toothed disc relatively to the toothed disc on the twist-
bar for the purpose of putting it into and out of gear therewith as required. I
have shown such a modification in Figure 5, the various details of the same being
illustrated in Figures 6 to 14. In this modification the discs C, D are not provided
with ratchet teeth as in Figure 1 but with ordinary V-shaped teeth. I have also
dispensed with the elastic material enclosing the outer disc, and with the central
rod or spindle for preventing longitudinal movement of the twist-bar. Instead of
the said central rod I utilize the cover A directly for supporting the twist-bar,
that is to say, I construct the cover so that it will bear against the end of the
disc C and prevent axial movement of the latter. In the drawing the disc C is

page_text: The said
shown provided with a circular recess C² in which is constructed to fit an annular
projection A3 formed on the cover A. The said projection abuts against the disc
and serves the same purpose as the rod G in Figure 1. The disc D accurately fits
the cylindrical chamber A2 of the casing A. It is prevented from rotating therein
by reason of it being formed with a hexagonal or other prismatic shaped head D³
of smaller diameter than the disc D which said head fits in a correspondingly
shaped chamber A in the cover A'. The chambers A2 and A' are of such length
as to allow the disc D to move axially until its teeth are out of engagement with
those of the disc C. I provide for moving the said disc D into and out of engage-
ment with the disc C automatically as follows, that is to say, I is a passage formed
in the covers A, A¹ and leading into the chamber A behind the disc D.
passage is continued through the metal of the cylinder as shown in Figure 14 and
eventually opens into the cylinder at a point near the lower or outer end thereof.
I is a groove in the twist bar forming a passage leading from the upper or inner
end of the cylinder to a cavity C³ formed in the disc C, whence another passage I¹
leads through the disc C to the space between the said disc C and the disc D.
The action of this modified device is as follows. During the forward stroke of the
drill the motive fluid under pressure that operates the drill enters through the
passages 1, and acts upon the face of the disc D driving the said disc backward
and disengaging its teeth from those of the disc C. The twist-bar is thus freed
from restraint and is consequently free to rotate so that no rotary movement is
imparted to the drill during its forward or operative stroke. When the compressed
air or other motive fluid enters the lower or outer end of the cylinder to cause the
drill to make its return stroke, the said fluid also enters the passage H and is con-
ducted thereby to the back of the toothed disc D forcing the said disc forward
into engagement with the toothed dise C. The latter disc is thus locked and
prevented from rotation during the return stroke of the drill, and the drill is con-
sequently partially rotated by the twist-bar. The arrangement herein shown and
described is very advantageous as the toothed discs are out of gear when the drill
is striking its blow, thereby avoiding excessive stress on the said discs and also
undue friction upon the twist-bar, thus obviating breakages. If in any case it.
should be desired to rotate the drill during the forward stroke instead of during
the return stroke, this can be done by reversing the arrangements of the
passages H 1.
In some cases I dispense with the passage H and substitute therefor a spring for
putting the discs in gear. Or I sometimes employ a spring for disengaging the
discs and use the fluid pressure for forcing them into engagement.
In another slight modification of my invention shewn in Figure 15 I use for
preventing the rotation of the twist bar a pair of toothed cones instead of the
toothed flat discs. I prevent rotation of the disc D by means of a transverse
bar D³ the ends of which fit into a corresponding recess A* in the cover A
The device may be actuated and the remaining portions of the machine constructed
substantially as hereinabove described with reference to the other figures of the
drawings.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent I declare that what I claim is :-
1. In a rock-drill, the combination with the twist-bar and toothed discs for con-
trolling the rotation of the said bar, of an elastic bearing for supporting one of the
said toothed discs, for the purpose specified.
2. In a rock-drill having toothed discs for controlling the rotation of the twist-
bar, mounting one of the discs in an india-rubber or like elastic bearing which is
capable of axial movement to permit of the disengagement of the disc teeth, and
which will yield when the twist bar is subjected to undue stresses, substantially as
and for the purpose specified.
3. In a rock-drill the combination with the twist-bar and toothed discs for

page_text: controlling the rotation of the said bar of a rod or spindle for taking the end thrust
of the twist-bar for the purpose specified.
4. In a rock-drill, the combination with the twist-bar and toothed discs for con-
trolling the rotation of the said bar, of a piston actuated by a spring or by fluid
pressure or by both spring and fluid pressure for maintaining the toothed discs in
contact.
5. In a rock-drill, automatically actuating the locking disc of the twist gear by
means of the fluid pressure in the cylinder, substantially as set forth.
6. In a rock-drill, automatically controlling the movements of the locking disc
of the twist-gear by a spring in combination with the fluid pressure in the cylinder,
one acting against the other substantially as described.
7. A rock-drill having toothed discs or toothed cones for controlling the rotation
of the twist-bar the said discs or cones being automatically disengaged when the
drill is giving its blow, for the purpose specified.
8. A rock-drill having twist gear constructed substantially as described with
reference to Figure 1 or to Figure 5 or to Figure 15.of the accompanying drawings,
and operating as specified.
Did this 0th day of March 1992
HASELTINE, LAKE & Co..
45, Southampton Buildings, London, W.C., Agents for the Applicant.