An Improved Percussive Tool Operated by Fluid Pressure, applicable as a Rock Drill and for other purposes.
Year: 1893

page_text: Date of Application, 23th Mar., 1893-4ccepted, 13th May, 1893
JUL
DIMIFICATION.
An Improved Percussive Tool Operated by Fluid Pressure, applicable
as a Rock Drill and for other purposes.
We, WILLIAM WHITE, Electrical Engineer of 58 Bread Street, in the City of
London, and JOHN FRANCIS CLEVERTON SNELL, Civil and Electrical Engineer,
of Trematon, Peterborough Road, Fulham 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 :-
Our invention relates to a construction of percussive tool operated by fluid
pressure wherein such fluid pressure is supplied through a fixed central tubular stem
entering the cylinder at the rear end, such tubular stem having two sets of lateral
openings through which the fluid pressure can enter the cylinder respectively at
the front and rear ends. Upon such tubular stem slides a tubular part of a rod
passing through the front end of the cylinder and constituting the percussion tool
holder such tubular part carrying a piston working in the cylinder on each side of
which piston the tubular rod has a set of lateral openings corresponding to those
of the fixed tubular stem but so arranged relatively thereto that when the
openings in the rod are situated over those of the tubular stem on one side of
the piston so as to admit fluid pressure into the cylinder, the other two sets of
the openings of the stem and. rod do not cover each other so that the fluid pressure
cannot enter on that end of the cylinder. The fluid pressure entering the one
end of the cylinder will drive the piston towards the other end until the piston
uncovers-ports in the side of the cylinder, through which the fluid pressure will
escape. When the piston and its rod have arrived in this position the other
set of openings of the piston rod will have been brought over the other set
of openings of the stem, so that fluid pressure will now enter at that end of
the cylinder and will drive the piston and rod in the contrary direction, and so on.
On the accompanying drawing is shewn a percussive rock drill operating
according to our invention.
Fig. 1 is a longitudinal section.
Fig. 1. Fig. 4 a section on line
the backward ports when open to
same when closed to the fluid, and
open to the fluid pressure.
Fig. 2 a plan. Fig. 3 a section on line X X
Y Y Fig. 1. Fig. 5 is a diagram shewing
the fluid pressure, Fig. 6 a diagram of the
Fig. 7 a diagram of the forward ports when
A is the central tubular stem, fixed to the framing of the drill by the head-
stock B and the distance pieces c¹². This stem passes right through the
cylinder K and has a rear set of longitudinal slots or ports d' through which the
fluid pressure can enter the rear end of the cylinder and a forward set d² through
which the fluid pressure can enter the front end. Over the stem A slides the
tubular part of the rod F having the piston I fixed thereon and extending through
stuffing boxes L' L' at each end of the cylinder, the front solid end constituting
the tool holder being also made to work through the bush r of the front head
stock q fixed to the distance pieces c¹ c². The rod F is there provided with a
helical groove h into which takes a tooth on the inner surface of the bush r.
This bush is rotatable in one direction in the head stock, and has fixed to it a
ratchet discs with which gears spring pawls t on the head stock, which allow
the bush to rotate in one direction but not in the other. Thus it will be seen
that as the rod F travels forward through the bush the ratchet and pawls will
allow it to turn the bush partly round by the action of the groove h upon the
tooth, but on the backward motion, the bush being prevented from turning, the
tooth in acting upon the groove h will cause the rod and its tool to turn partly
round.

page_text: The cylinder K has at or about the middle of its length two opposite ports M
open to the atmosphere which are more or less uncovered by the piston towards
the end of each of its strokes. On the outside of the cylinder is formed or fixed a
nut N through which screws the advancing screw spindle O turned by hand, the
nut N being also made to serve as a slide working in a guide carriage P arranged
to swivel in any suitable support.
The action of the above described machine is as follows. Assuming the piston
and piston rod to be in the position shewn on the drawing with the ports g¹
uncovering the ports of the stem A, and fluid pressure to be supplied to the
latter from a suitable reservoir, this fluid pressure in entering the rear end of the
cylinder will force forward the piston piston rod and tool.
When near the end of the stroke the ports g', on F will have entirely passed off
the ports d', so that these will be closed, and the supply of fluid pressure cut off,
and after the piston has travelled a little farther causing the drill or other tool to
perform its percussive action the piston will uncover the ports M so that the fluid
pressure contained in the rear end of the cylinder will now escape into the
atmosphere.
At the same time the ports g² of rod F will have arrived over the ports 2 of
stem A, so that the fluid pressure will now enter the frout end of the cylinder and
force the piston I together with rod F and its tool backwards. As during such
motion the rod F is turned through part of a revolution, as before described the
ports g2 are formed with a corresponding curvature as shewn at Fig. 2, in order to
maintain the ports d² open during the greater part of the stroke. When the piston
arrives at the cylinder ports M as at Fig. 1 again the fluid pressure escapes, where-
upon the forward stroke is repeated as above described.
The pitch of the groove is so proportioned that at every back stroke the rod
will be turned such a distance as will bring the ports g¹ g² from one of the ports d' d²
to the next ports.
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. A permanent tool operated by fluid pressure wherein the fluid pressure is supplied
to the cylinder of the apparatus through a tubular stem such as A having two sets
of ports such as d¹ d² situated respectively in the front and rear ends of the cylinder
a tubular rod such as F fixed to the piston and carrying the operating tool, being
made to slide over the stem A. such rod having two sets of ports such as g' and g
which as the rod and piston are made to reciprocate by the fluid pressure alternately
uncover and cover the ports d¹ d² so as to control the admission of fluid pressure
substantially as described.
2. The construction of percussive tool combined and operating as herein described
with reference to the accompanying drawings.
Dated this 28th day of March 1893.
ABEL & IMRAY,
Agents for the Applicants.