Improvements in Rock Drills.
Year: 1890

page_text: e of Application, 18th Feb., 1890-Accepted, 22nd Mar., 1890
COMPLETE SPECIFICATION.
Improvements in Rock Drills.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention which has
been communicated to me from abroad by Addison Crittenden Rand, of the City,
County and State of New York, United States of America, Mechanical Engineer,
and Joseph Clements Githens, of Ashbury Park, County of Monmouth, State of
New Jersey, United States of America, Mechanical Engineer, and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
This invention relates to improvements upon several parts of a rock-drill-
Figure 1 is a plan of a rock-drill, the lower-head being shown partly in section ;
Figure 2 is a cross-section of the lower-head;
Figure 3 is a side view of the lower-head ;
Figure 4 is a view in perspective of the clamping-shoe;
Figure 5 is a vertical, longitudinal section of the central portion of the cylinder
and steam-chest of a rock-drill;
Figure 6 is a vertical, lateral section of the same parts;
Figure 7 is a horizontal section of the same parts;
Figure 8 is a perspective view in detail of the rocker-valve pivot-block;
Figure 9 is a vertical cross-section of a chuck for rock-drills; and
Figure 10 is an elevation in perspective of a form of bushing for the chuck.
In Figures 1, 2 and 3 the lower-head of the drill-cylinder is made in longitudinal
sections A A', such form of said head being prevalent in rock-drills in which the
tool-holding chuck is made integral with the piston-rod. A is the cylinder, and A³
the piston rod. Upon the outer edges of the meeting-faces of the sections A A¹ of
the lower-head are formed the laterally projecting flanges a, a¹, respectively, said
flanges being adapted to correspond to and coincide with each other at the section
edges when the sections are united. The contiguous under faces of the respective
pairs of flanges a, a' meet each other flatwise as substantial continuations of the
meeting-faces of the sections. The opposite or upper faces of said flanges are
inclined as shown at a' so that each flange has a taper from the upper end of the
head toward the lower end, and so that, when the flanged sections are united the
coinciding flanges thereof will constitute a wedge-like projection at the section-
edges, with the narrow end of the wedge toward the lower end of the head. The
upper faces a of the flanges are preferably given a downward inclination from the
flange-edge toward the body of each section, so as to form a dove-tail, or its equivalent,
of the united coinciding flanges.
B are clamp-shoes each of which is formed with a tapered and preferably
dove-tail channel b extending from end to end through the shoe, and adapted to
fit upon the united wedge-like flanges a, a'. The shoes thus clamp the sections of
the lower-head together. The long-bolt B¹, extending from the yoke B² at the
upper end of the drill, and reaching longitudinally of the cylinder to the lower ends
of the shoes B, engage said shoes and serve to draw the shoes upward on the
wedge-like flanges of the sections and thus bind said sections together. The bolts B¹
may have the broad laterally extended heads 6' adapted to reach across the under
ends of the shoes, and the external side of each shoe may be channelled at 6' to afford
a seat or way for the bolts B'. If desired, the shoes may be bored longitudinally,
with the bolts B¹ passing through them.
At c, Figure 1, is shown a ring which is of an external diameter adapting it

page_text: to be seated, as by a screw-thread, at the bottom of the recess a' in the lower end of
the lower-head of the cylinder. The internal diameter of this ring is greater than
the diameter of the piston-rod, so that an annular space will exist between the rod's
surface and the internal face of the ring. At c' is a follower adapted to screw into
the mouth of the recess a³. The object of the ring c is to enable the use alternatively,
at pleasure, of a leather packing-ring.c³, or of the ordinary cotton-waste, or
equivalent packing, around the piston-rod. The packing-ring has its flange
seated between the ring c and follower c', its body lying between the surface of the
piston-rod and the internal face of the ring c. By withdrawing the ring c and
packing-ring &, the recess may be left free and open for the use of ordinary packing
in connection with the follower.
In Figures 5, 6 and 7, A' is the cylinder; A* the piston; A³ the valve-chest with
its bonnet A in which the slide-valve A' works. D is the rocking-lever which actuates
the valve A', an arm & thereof engaging said valve, and the arms d¹ thereof having
respectively the inclined under faces d' and d' adapted to engage the inclined faces a
on the piston, which is recessed, as shown, for the purpose. The cylinder and
valve-chest have the usual inlet and outlet ports and passages.
At E are shown metal blocks, preferably of steel and rectangular, and seated in
corresponding recesses in the cylinder-wall immediately under the plate A° of the
valve-chest and one on each side of the opening a' in the cylinder-wall in which
the rocking-lever 1 plays. The blocks are correspondingly bored laterally at e to
receive the pivot-pin d of the rocking-lever. The blocks are given a yielding or
spring-like seat in their respective recesses in the cylinder-wall, in the direction
between the bottom of said recesses and the valve-chest plate A³. For this purpose
the blocks E are fitted somewhat loosely in said recesses, and they are preferably
provided with spiral springs F seated in suitable recesses e' in the blocks, and which
springs thus have a bearing against the under face of the valve-chest A'. At e² is a
projection on the upper face of each block E adapted to fit into a corresponding
groove a in the under face of plate A and serving to prevent lateral movement of
the blocks E in their seats.
Upon each side of the cylinder-wall beyond the block-recesses are preferably formed
the bonnets G, so that the seated blocks E are wholly enclosed within the cylinder-
body, and at the same time access is afforded to the block-seats to enable them to be
properly finished with suitable tools.
The principal advantage obtained by this described construction, is that the blocks E
may be formed so as to be readily removed from their seats when the pivot-hearing e
becomes worn, and others inserted in their place, the blocks being interchangeable in
the several sizes of rock-drills.
In Figures 9 and 10 is shown an improved tool-holding chuck for rock-drills.
His the shell or body of the chuck carried on the end of the piston-rod, for the
detachable attaching thereto of the drill-bar or bit. The shell is recessed at h and
slotted on one side at h¹. In this slot a key H¹ has play, and said key is adapted to
project into the recess h, as shown, and on its inner end has a bearing-face h2, pre-
ferably a plane. H2 is a bushing, adapted externaily to fit into the recess in the
shell H. Upon the internal faco.or bore of the bushing, is a bearing face, or faces;
namely, a plane face 3 diametrically opposite to the face of the key, or two plane
faces,, at right angles to each other and located opposedly to the face of the
key, with their planes at an angle, on either side, to said face h'. The bushing is
slotted longitudinally at to register with the slot in the chuck-shell, thereby
permitting the play of the key H' in the hushing.
The bushing may be formed as shown in Figure 10, namely, with inclined longi-
tudinal edges h so as to give the bushing a longitudinal taper, and a semi-cylinder H
having oppositely inclined edges h³, which may be driven into the recess h after the
bushing H2 is seated, thus serving to hold the bushing H' firmly in place. In this
case the part H' is given a slot 4 registering with the slot in the shell..

page_text: H is a U-bolt the limbs h of which extend through apertures in the shell H,
and the arch 10 of which engages the outer end of the key H¹, the limbs having
fastening nuts as shown. This U-bolt may be advantageously used to hold and
adjust the key in the chuck and bushing, although it is not intended to limit this
feature of the invention to the use of such bolt, as other devices for this purpose may
be employed.
The advantage obtained by this described chuck and bushing is, that a drill-bar or
bit formed of octagonal steel, which is the usual form in which commercial bar steel
is manufactured and sold, may be seated in the chuck and held firmly between the
key and the bushing having the described bearing-faces.
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 I
claim is :-
1. In a rock-lrill, the combination with the separable, longitudinal sections of the
lower cylinder-head, of the tapered flanges a a' extending longitudinally of the
respective sections at their edges, together with clamp-shoes B having tapered
channels b, and the bolts B' engaging said shoes, substantially as set forth.
2. In a rock-drill, the combination with the lower cylinder-head having the recess
or enlarged internal diameter a³ at its lower end and the follower c' adapted to fit
and be detachably seated in said recess, of the removable ring c having an internal
diameter greater than that of said follower, and adapted to be seated in the bottom of
said recess, and with the said follower to furnish a clamping seat for a packing-ring c²,
substantially as set forth.
3. In a rock-drill, the combination with the cylinder, piston and valve-chest, of
spring-seated blocks in the recessed cylinder wall, and the valve rocking-lever pivoted
in said blocks, substantially as set forth.
4. In a rock-drill, the combination with the cylinder, piston and valve-chest, of
spring-seated blocks in the recessed cylinder-wall, and having on their upper faces
projections adapted to fit into corresponding recesses in the valve-chest wall, together
with the valve rocking-lever pivoted in said blocks, substantially as set forth.
5. In a rock-drill, the combination with the cylinder, piston and valve-chest, of
the blocks E seated loosely in corresponding recesses in the cylinder-wall and provided
with springs F seated in.recesses in said blocks, and the valve-rocking-lever pivoted
in said blocks, substantially as set forth.
6. The metal block E having the cylindrical lateral aperture e, the recesses e¹
opening on its upper face, and the projection e² on said upper face, together with
springs F seated in and extending from said recesses, whereby said block is adapted
to be intorchangeably seated in the recessed cylinders of rock-drills immediately
beneath the valve-chest thereof, and to serve as bearing for a pivot-pin of the valve-
rocking-lever therein, as described.
7. In a rock-drill, the combination with the cylinder, its piston and valve-chest, of
spring-seated blocks E in the recessed cylinder-wall, constituting bearings for the
pivot-pin of the valve-rocking-lever, and the bonnets (i on the cylinder-sides enclosing
said seated blocks, substantially as set forth.
8. In a chuck for rock-drills, the combination with a solid chuck-body, recessed and
slotted as described, of a busking fitted in said recess and provided with plane bearing-
faces, one or more, longitudinal of its bore, and having a slot registering with the slot
in the chuck-body, together with a key fitted to play in said slots and carrying a bearing-
face opposed to the bearing-face, or faces, of the bushing, and adapted to be projected
into and withdrawn from the bushing-bore, substantially as set forth.
9. In a chuck for rock-drills, the combination with the solid chuck-body, recessed
and slotted as described, of a bushing composed of the semi-cylindrical sections H*
and H seated in said recess in the body, and having inclined adjacent edges, as
described, the section H* having longitudinal bearing-faces, one or more, and the

page_text: section H³ being slotted to register with the slot in the chuck-body, together with a
key fitted to play in said slots and adapted to be projected into and withdrawn from
the bushing-bore, substantially as set forth.
Dated this 18th day of Wahrneny, 1900
ALLISON BROS.,
Agents for the Applicant.