Year: 1887

page_text: Date of Application, 16th Aug., 1887
Complete Specification Left, 16th May, 1888
Complete Specification Accepted, 3rd Aug., 1888
I, JAMES MCCULLOCH, of 20 Marlborough Road, Manchester, in the County of
Lancaster, Engineer do hereby declare the nature of this invention to be as follows:-
My invention relates to valves and valve-gear, chiefly designed for rock-drills.
The distributing valves of rock-drills have, in some instances, been arranged to be
operated by means of a tappet actuated by the piston or piston-rod in its to-and-fro
movement. In such cases, it is necessary to use a spring for retaining the valve in
position at either extremity of its stroke or movement while the projection on the
piston or piston-rod is out of contact with the tappet; and considerable inconvenience
is sometimes occasioned by the failure of the said spring to properly fulfil its function
by reason of diminution of its strength, or by the friction caused by excessive-
tightening of the said spring. In other instances, the valves of rock-drills have been
arranged to be operated by air-pressure. This arrangement is unreliable as the
valve is liable to be rendered inoperative by the entrance of sand, grit or the like
between the working surfaces, the air-pressure being insufficient to overcome the
increased resistance to movement of the valve.
By my invention, I obviate these defects and provide for operating a distributing
valve in an efficient and reliable manner by the combined action of a tappet or
similar device and of fluid-pressure.
In carrying my said invention into practice, I employ a piston-valve arranged to
be operated by a tappet actuated by the piston or piston-rod in its to-and-fro move-
ment, and I so arrange the admission ports or passages that, when the valve is moved
to one end of its stroke by the tappet, it will close one of the said ports and the
other port, and the pressure of the compressed air or other fluid, acting upon the said
open
.

page_text: valve, will retain the same in position, and thus prevent movement thereof while the
projection on the piston or piston-rod is out of contact with the tappet.
When my invention is applied to a rock-drill, I prefer that the exhaust should take
place through holes in the walls of the cylinder. Other provision may, however, be
made for the exhaust.
Suitable buffers or cushions are provided for preventing or diminishing concussion
at the termination of each stroke or movement of the valve.
It is evident that my invention is applicable to other machines than rock-drills;
and that the apparatus may be modified, according to the requirements of the machine
to which it is to be applied, without departing from the nature of my said invention.
Dated this 16th day of August 1887.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements relating to Valves and Valve-gear, Chiefly Designed
for Rock-drills.
I, JAMES MCCULLOCH, of 20 Marlborough Road, Manchester, in the County of
Lancaster, Engineer do bereby 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 valves and valve-gear, chiefly designed for rock-drills.
The distributing valves of rock-drills have, in some instances, been operated by
means of a tappet actuated by the piston or piston-rod in its to-and-fro movement. In
such cases, however, it has been necessary to use a spring for retaining the valve in
position at either extremity of its stroke or movement, while not acted upon by the
piston or piston-rod, and considerable inconvenience has been occasioned by the failure
of the suid spring to properly fulfil its function by reason of diminution of its strength
or by the friction caused by excessive tightening of the said spring. In other instances,
the valves of rock-drills have been arranged to be operated by air-pressure. This
arrangement is unreliable as the valve is apt to flutter or stick or be rendered
inoperative by the entrance of sand, grit or the like between the working surfaces, the
air-pressure then being insufficient to overcome the increased resistance to movement
of the valve. The springs, moreover, offer great resistance to the movement of the
piston and cause considerable wear of the working parts, and, when these parts are
slightly worn, the apparatus will not work properly (the valve not being kept in its
proper place), until the springs are renewed or readjusted. A great amount of trouble
and inconvenience is thus caused, especially when working underground.
In the valveless machine, moreover, the motive fluid is in constant communication
with the piston, thereby causing great resistance to the movement of the piston and
waste of the fluid.
By my invention I obviate the above-mentioned defects and provide for operating
a distributing valve in an efficient and reliable manner by the combined action of a
tappet or similar device and of fluid pressure.
In the accompanying drawings I have shown how my said invention can be con-
veniently and advantageously carried into practice.
Figure 1 is a side elevation showing the application of my said invention to a
rock-drill.
Figure 2 is a plan.
Figure 3 is a longitudinal vertical central section.
Figure 4 is a vertical section on the line,
Figure 3.
Figure 5 is a vertical section on the line ', ¹ Figure 3.
Figure 6 is a vertical section on the line y, y Figure 3.
Figure 7 is a vertical section on the line y¹, y¹, Figure 3.
Figure 8 is a plan and
Figure 9 a section on the line z, z Figure 8 showing a modification hereinafter
described.
Figure 10 is a plan and
Figure 11 is a section on the line 2, Figure 10 showing a further modification.
Like letters indicate corresponding parts throughout the drawings.
A is the cylinder, B, B¹ are the cylinder covers C, C' are the pistons, D is the piston
rod, E is the stop cock and F the supply pipe, G is the socket for holding the drill H.

page_text: I is the bracket carrying the cylinder. Jis a handle for feeding the drill to or from
its work by means of a screw hereinafter referred to.
a is a valve adapted to be moved by a tappet which is pivoted at to the
cylinder A and is actuated by a swelling or enlargement upon the piston-rod D. The
air or other fluid delivered through the supply pipe F and stop cock E is caused by
the tappet-valve a to pass alternately through the two channels or passages a¹ to the
extremities of the cylinder A, and expands in the said cylinder. Holes d, d, are formed
in the cylinder A, through which the exhaust will take place.
After the air or other fluid has been exhausted through the apertures d, atmospheric
air enters the cylinder and is compressed at either end of the stroke. The air thus
compressed provides a safe cushion at each end of the said stroke, and prevents damage
to the covers B, B' by the pistons C, C. The air compressed as above described
expands in the return stroke of the pistons C, C and thereby augments the power or
initial pressure tending to move the said pistons. When the pistons C, C³, are
performing their forward stroke or movement, that is to say, the stroke in which they
deliver the cutting blow of the drill H, resistance due to the above described cushioning
does not offer any appreciable opposition to the force of the cutting blow of the drill
except when the pistons travel too far, as for instance when the said drill comes in
contact with soft places in the rock, or when the apparatus is not kept up to its proper
working position. The atmospheric air is prevented from entering the channels or
passages a through which the motive fluid is delivered to the cylinder A, by valves e
provided with seatings f. The valves e are normally retained closed by springs g.
When the atmospheric air is being compressed as hereinbefore described in either end
of the cylinder, the pressure of the said air tends to press the valve e in that end of the
cylinder A, tighter upon its seating whilst the valve e in the other end of the said
cylinder is opened by the air or other fluid delivered by the tappet valve a through
the passage a¹, the pressure of the said air or other fluid being sufficient to overcomo
the strength of the spring g. This action takes place alternately at either end of
the cylinder.
An important feature of my said invention is the construction and arrangement of
the distributing valve and its adjuncts in such a manner that, when the said valve is
moved to one end of its stroke to close one of the said ports and open the other port,
the pressure of the compressed air or other fluid, acting upon the said valve, will retain
the same in position, and thus prevent movement thereof while the projection or
enlargement c of the piston rod D is out of contact with the tappet b. For this
purpose I make the said valve as shown and fit it to slide in a cylinder or casing a³
provided with an oil hole a³. The said valve is provided with recesses or cavities a
in which works the extremity 63 of the tappet b. I moreover provide steel discs a³
having India-rubber discs a in the centre; against these steel discs the surface of one
or the other end of the valve a will be pressed by the tappet at either extremity of
its movement. When desired the valve a can be reversed and the extremity 6 of the
tappet 6 inserted in the other recess or cavity a*. When at either extremity of its
movement the valve a closes the port through which the compressed air has access
to it so that the said end of the valve is no longer subjected to the pressure and the
compressed air acting upon the remaining surfaces of the valve will tend to keep it
pressed against the said disc.
To impart rotary or angular motion to the drill H upon or about its axis at the
same time that it delivers its cutting blow, a spindle his fitted in the cylinder cover B¹.
The spindle h is provided with spiral grooves ', in which are adapted to fit corre-
sponding feathers or projections upon a bush i fitted in the piston Of which is recessed
or hollowed out for that purpose, a hole or cavity jis also provided in the piston rod D
to receive the spindle h during the inward stroke of the pistons. The spindle his,
moreover, provided with a ratchet-wheel k with which engages pawls k¹ actuated by
springs during the outward stroke of the pistons. When the drill H is making its
cutting blow that is to say, when the pistons C, are making their outward stroke,
the said pistons, the piston rod D and the drill H are caused to rotate by the action of
the grooved spindle h upon the piston C. Upon the return stroke the pawls k' do

page_text: not engage with the ratchet-wheel k, and the latter with the spindle is free to
revolve.
The cylinder A is provided with V shaped projections and is arranged to slide in
corresponding grooves in the bracket 1. To feed the said cylinder and consequently
the drill H to or from its work, I provide a screw threaded spindle m carried in a
suitable bearing m¹ in the bracket I and in a bearing m² in an extension m³ of the said
bracket. The screw threaded spindle m is arranged to engage with corresponding
threads in nuts n attached to the cylinder A. This spindle m is worked by means of
the crank handle J as above stated. To take up any wear that may take place in the
screw threads upon the spindle m or in the nuts n, the latter are provided with right
and left handed screw threads n¹ upon the outside of the same. The nuts n are fitted
with a nut o having right and left handed screw threads adapted to engage with the
external screw threads upon the said nuts n, thus by turning the nut o any wear can
be taken up and the jar to which machines of this kind are liable after a little wear is
obviated. Nuts p are provided for taking up the wear in the journal m³.
Suitable packing q is provided round the piston rod D and grooved spindle h.
Screw-threaded plugs r are provided, by removing which, the tappet valve a can be
taken out for inspection or repairs. A screw threaded plugs is also provided to permit
access for oiling or inspecting the ratchet-wheel and the pawls k¹.
Figures 8 and 9 illustrate a modification wherein the cylinder A is arranged to
slide in a bracket I having at one side a V-shaped groove in which is adapted to slide
the corresponding V-shaped projection 11 upon the said cylinder: The V-shaped
projection upon the other side of the cylinder is adapted to slide in a recess t provided
with a setting up strip t¹. The strip t¹ can be set up by means of set screws u when
necessary so as to take up any wear that may occur.
Figures 10 and 11 illustrate a modification wherein the bracket 1 is provided with
a removable part or portion attached to the bracket I by means of the bolts or
screws w. This arrangement permits the cylinder A to be easily and expeditiously
removed from the said bracket when desired.
Although I have herein before described my apparatus as applicable more especially
to rock drills it is obvious that it is also applicable to other kinds of machines.
It is obvious, moreover, that I can somewhat modify the construction of my
apparatus without departing from the nature of my said invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I wish it understood
that I claim :-
:-
First. For distributing fluid under pressure in a rock-drill or other machine, a
valve operated by a tappet and so constructed and arranged that, when moved to
either end of its stroke, it will be held in position by the pressure of the fluid, for the
purpose above specified.
Second. The combination of parts comprising the cylinder provided with the
exhaust holes or apertures, the valve and tappet, the projection or enlargement on the
piston-rod and the check-valves, substantially as, and for the purposes, set forth.
Third. The arrangement of the exhaust holes or apertures in such a manner that
cushioning of the pistons will be caused at either end of their stroke, substantially as
described.
Fourth. The improved valve and valve-gear consisting of the parts constructed and
combined substantially as described with reference to the accompanying drawings.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.