IMPROVEMENTS IN MACHINERY FOR DRILLING OR BORING ROCKS AND OTHER HARD SUBSTANCES, PARTS OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER PURPOSES
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by William Wallace Dunn at the
Office of the Commissioners of Patents, with his Petition, on the
7th February 1874.
I, WILLIAM WALLACE DUNN, of San Francisco, California, United
States of America, now of No. 8, Southampton Buildings, London,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN MACHINERY FOR DRILLING OR BORING ROCKS AND OTHER HARD
SUBSTANCES, PARTS OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER PURPOSES,"
to be as follows:-
My Invention relates to improvements in machines of that class in
which the drill or perforating implement is carried and operated by a
piston driven to and fro by the pressure of steam or other elastic fluid.
The said Invention consists,―
First. In novel means for effecting the rotation of the piston and drill
or perforating implement during the working of the machine.
Secondly. To mechanism for operating the valve which controls the
admission of the steam or other fluid to the cylinder of the drilling
machine.

page_text: Thirdly. In automatic mechanism for producing the feed or advance of
the drill into the rock or other substance being perforated.
Fourthly. To a peculiarly constructed friction device to be applied to
the feed motion of these machines and for other purposes as herein-after
explained.
Fifthly. To a novel contrivance for indicating the proper regulation of
the feed or advance of the drill when the same is effected by hand.
Sixthly. In the employment in combination with the above-described
improvements of means for cushioning the piston and ensuring its quick
recoil at the end of each stroke.
Seventhly. To the peculiar construction of the framing and of the
joints for supporting the machine on the same.
Eightly. To the combination of these various improvements or any of
them with the other parts of the machine, as herein-after described.
The rotation of the piston and drill is effected as follows:-In the
centre of the piston I arrange a friction cam which is fitted to turn
therein. The said cam has two spiral portions between which and the
periphery of the piston I place small rollers. To the end of the cylinder
I secure a spiral or twisted rod which extends inward and enters a hole
in the said cam and passes through the same and the piston, the piston
rod being made hollow for some part of its length. As the piston moves
forward in the cylinder the spiral or twist of the said rod turns the cam
in the direction in which it exerts no pressure upon the piston, therefore
the piston and drill do not turn; but in the backward stroke of the said
piston the spiral rod turns the cam in the opposite direction, thereby
causing it to bind tightly against the said rollers, so that the piston
turns with the said cam and the drill receives the required rotation on
its axis. Springs are arranged in combination with the said rollers to
assist their action.
I modify this part of my Invention by substituting for the aforesaid
rollers pawls fitted to turn in holes or sockets made in the inner side of
the piston's periphery, and projecting not radially but obliquely inward,
their inner extremities lying in contact with the central hub or boss of
the cam. In the backward stroke of the piston the said cam is turned
by the action of the spiral rod in the direction in which these pawls are
made to approach a radial position, and thereby gripe the piston and

page_text: rotate the same and the drill, but in the forward stroke of the said piston
the cam turns in the opposite direction, the pawls are pressed back by
springs, and the piston and drill do not turn.
The part of my Invention relating to the operation of the valve is
carried into practice as follows:-On the piston rod I fix a double cone
or incline, the two ends of which are preferably made capable of endwise
adjustment to or from each other by a screw or otherwise on the said
rod. In combination with this double cone I arrange a three-armed
lever which oscillates on a pivot or fulcrum secured to the cylinder
frame. Two of the arms of this lever occupy such a position as to be
moved by the two ends of the said cone; as the piston rod moves to and
fro the third arm is connected to the valve rod or stem, so that the
oscillating movement given to the said lever by the alternate action of
the cone on its two arms will communicate to the said valve rod the
required to-and-fro movements.
Instead of connecting an arm of the said lever to the valve rod, as
above described, I may form the latter with a toothed rack and provide
the said lever with a sector, whereby it is geared with the said rack.
This part of my Invention may also be carried into effect by means of a
toothed sector pivoted to oscillate on the cylinder frame and geared with
a circular rack formed on the piston rod, in combination with a lever
formed with a slot to receive a pin or stud projecting laterally from tho
vibrating sector. This lever has two arms, one of which is connected to
the valve stem and the other is formed with the aforesaid slot. The
latter is so formed that when the said sector is vibrated by the rack on
the piston rod, as the latter moves to and fro, the said pin or stud acting on
the sides of the said slot causes the lever to oscillate on its fulcrum and
thereby impart the required movement to the valve rod or stem. The
inclination of the sides of the said slot and also the configuration of the
aforesaid cone are such that the motion of the valve will be slow at the
beginning of each stroke so as to open the admission port gradually, and
quick at the end of the stroke to close the said port and open the exhaust
port quickly.
11

page_text: suitable material. The feed screw is fitted to turn in bearings fixed
inside this bed and passed through a nut on the cylinder. The said
screw is provided with a friction device, whereby it receives an inter-
mittent motion from a lever which is actuated by the piston rod. For
this purpose the said piston rod is provided with two shoulders,
abutments, or collars, and the lever has on one arm projections which
embrace the said rod and occupy such positions as will insure them
being struck by the said shoulders or abutments as the said rod moves to
and fro. The lever is thus caused to vibrate on its fulcrum. The other
arm of the said lever is connected by a link or rod to the lever of the
friction device, which is thereby caused to oscillate around the screw
and impart the required motion to the same through the aforesaid friction
device.
The construction of this device is peculiar, and it is applicable not
only to the purpose above described but also to other machines or
apparatus, wherein it is necessary or desirable to give an intermittent
motion to any part of the same, such for instance as drilling braces, the
feed motion of planing and shaping machines and the like.
The said friction device consists of a circular plate or disc with an
outer flange or rim, and which is securely fixed on the screw shaft or
other part to be operated, and a lever formed with jaws fitted to embraco
the said flange and to work upon the same. One of the jaws is bent, and
extends under the said flange, so that the latter is enclosed between this
bent portion of the said jaw and the back or solid portion of the lever.
One edge of the bent portion of the jaws is fitted in close contact with
the inner periphery of the said flange or rim, and that edge of the outer
portion of the lever which is farthest from this inner edge is fitted closely
to the outer periphery of the flange. When the lever is turned forward
these edges are forced upon the inner and outer surfaces of the flange and
gripe it so tightly that it cannot slip, and is therefore compelled to move
with the lever; but when the latter is turned backward the said lever
moves freely over the flange, and the plate or disc remains stationary
while the lever returns to grasp a fresh portion of the same.
I attach a
spring to the jaw under the rim or flange and arrange it to bear on the
latter to prevent any play or lost motion of the lever.
Instead of operating the feed screw automatically as above described
I may operate the same by hand. The nut through which the screw

page_text: passes may be fixed either on the cylinder or on the frame in which the
latter is supported and slides. The feed screw is provided with a handle
or hand wheel, which is turned by the attendant to advance the drill as
the work progresses.
I employ in combination with this feeding
apparatus a peculiar device for indicating the rate at which the feed
screw should be turned, so that the feed may be properly regulated.
This device, which I term a pulsator or feeler, consists of a light two-
armed lever fitted on a pivot and formed with fingers at its two extre-
mities, which lie in contact with the piston rod. The latter has
projections or shoulders, which if they touch the said fingers cause a
slight pulsation or vibration of the said lever arm. But these fingers
and projections are so arranged in relation to each other and the
stroke of the piston that this action of the pulsator only occurs when
the drill has not properly advanced to its work, so that it indicates to the
attendant the necessity of a quicker advance. I may connect with the
.device a bell or other sounder.
'
For cushioning the piston at the end of the forward stroke and
effecting the recoil or return of the same when steam is not admitted to
the forward side of the piston I form in one side of the cylinder a small
aperture for the admission of air. This aperture admits at each forward
stroke a small quantity of air, which is compressed as the piston
approaches the cylinder end and then expands and forces the piston back.
I also in some instances provide the machine with an air cylinder, placed
in front of the main cylinder and fitted with a piston on the same rod as
the piston of the said main cylinder. Air is admitted to this air cylinder
to cushion the piston thereof at the backward stroke of the drill, and to
assist the steam in driving it forward. When these two cylinders are
employed they are placed far enough apart to permit the aforesaid valve,
operating devices, and feed mechanism to be arranged between them.
The joints for connecting my improved drilling machine to its sup-
porting frame or stand are constructed as follows:-I form a strong bar
with trunnions, which are fitted to turn freely in suitable bearings in the
said stand, and are provided with pinching screws or other means for
locking them in any position. To the centre of this bar I attach a block,
in which I form a conical or taper socket. In this socket I fit a taper
plug, which is formed or attached to the frame or bed in which the
cylinder rests. Through this socket and plug I pass a strong bolt pro-
vided with a screw nut. This plug turns freely in the said socket to

page_text: permit the adjustment of the cylinder to any angle in a plane inter-
secting that in which it is adjusted by turning the aforesaid trunnion
bar, and the plug is made fast when adjusted by its screw bolt and
nut.
I modify the construction of this joint as follows, that is to say, I
attach to the trunnion bar a strong clip ring in the place of the said
conical socket. In this clip ring I fit a cylindrical piece projecting from
the cylinder frame. The clip ring is provided with pinching screws,
whereby it is slackened to allow the cylindrical piece to turn freely in it
and is then tightened to hold the same securely. By the above-described
joint I can adjust the drill in two intersecting planes, but by the
following construction I provide a joint which permits its adjustment in
three intersecting planes. I construct a round bar or pillar, on which
a strong clip ring, which is fitted to slide endwise or to turn upon
the said pillar, and is provided with pinching screws. One side of this
ring is formed to receive one flange of a rectangular bracket, which is
secured by a strong bolt to the face of the ring, and is adjusted therein
and secured by the said bolt as required. On the other flange of the
said bracket is secured either a cylindrical or conical socket, in which the
cylindrical piece of the cylinder frame is fitted to turn, and is provided
with screws for securing it as above described.
I also furnish the supporting stand of my machine with further means
for adjustment, which will be found of great utility when it is required
to bore oblique or slanting holes in rocks whose top or horizontal surfaces
only are accessible. For this purpose I provide the stand with an arm
whose lower end is jointed to the said stand by a socket and plug con-
structed as above described, and whose upper end is connected to the
cylinder bed or frame by a similar joint.