Improvements in Machines for Drilling or Periorating Rocks US other Hard Substances
Year: 1888

page_text: Date of Application, 4th June, 1888
Complete Specification Left, 4th Mar, 1889
Complete Specification Accepted, 6th Apr, 1889
Improvements in Machines for Drilling or Periorating Rocks US
other Hard Substances
We, JOHN HFNBY HOLMAN and JAMES MINERS HOLMAN, both of the Camborne
Foundry and Engine Works, Camborne, in the County of Cornwall, Engineers, do
hereby declare the nature of this invention to be as follows
-
Our invention relates to machines for drilling or perforating rocks or other hard
substances and especially to machines of the kind described in the Specification of
Letters Patent dated October 19, A D 1881, No 4567, and it comprises several
improvements designed to render such machines more simple in construction, more
efficient in operation, and less liable to derangement than heretofore
According to our said invention the cylinder has cast integral therewith on
diametrically opposite sides angular or V-shaped ribs which are adapted to slide in
Corresponding V-shaped guides carried by the cradle
Through the said ribs, and parallel with the cylinder, are formed holes through
which are inserted bolts for securing the cylinder covers and other parts
The slide valve for controlling the supply of steam or other motive fluid to the
cylinder is operated through the medium of a tappet from a central projecting portion
of the piston rod
The tappet is so constructed that it is impossible for it to fall over and catch
between either of the outside pistons and the centre one as in the machine described
in the Specification before referred to The buffers or pads described in the said
Specification are according to this invention dispensed with
The twist gear by means of which a partial rotation is imparted to the tool at each
stroke of the piston comprises a threaded rod extending through the cylinder cover
and into the piston, and having on its outer enda ritchet wheel located in a recess
in the cylinder cover and engaging with a pawl or pawls These parts are kept in
place by a back cover without the aid of screws or studs so that they can be readily
moved

page_text: The traverse of the cylinder in the cradle is effected by means of a single screw
passing through a nut secured in the cradle and having bearings in the back and front
cylinder covers
In order to provide for the wear of the cradle a groove is formed on each of
tho guides of the latter and extended the whole length of the same In these
grooves are fitted filling pieces properly secured at the end so as to prevent any
longitudinal movement
This
These filling picces are advanced to compensate for wear by set screws
adjustment can be effected without thing the machine to pieces or even removing it
from the supporting column, car or tripod which is an advantage not possessed by
other machines
Dated the 4th day of June 1888
G F REDFERN & Co
4, South Street, Finsbury, London,
Agents for the Applicants

page_text: The tappeto and central projecting piston p are constructed as shown in Figure 1
so that it is impossible for the tappet to fill over and catch between the centre and
either of the outside pistons as in the machine described in the Specification before
referred to
The twist gear by means of which a partial rotation is imparted to the tool at each
stroke of the piston comprises a threaded rod r extending through the cylinder cover m
and into the piston rod 9 and having on its outer end a ratchet wheels located in a
recess in the cylinder cover m and engiging with pawls u, u as shown in Figure 3
These parts are kept in place by a back cover without the aid of screws or studs,
so that by removing the said cover they can be readily inspected without dismounting
the apparatus
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) In a rock boring or drilling machine, the arrangement of the cylinder to
work in guides of the kind hereinbefore described, the said guides being
provided with filling pieces which can be adjusted to compensate for wear, substan-
tially as set forth
(2) The construction of the tappet and central projecting piston for operating the
valve, substantially in the manner herein before described and as shown in the drawing,
for the purpose specified
(3) In a rock boring or drilling machine the arrangement of the twist gear in such
a manner that the ratchet wheel and pawls are located in a recess in the rear of the
cylinder cover and retuned in place by a cover without the ud of screws and studs,
subst intilly as, ind for the purpose, described
5
(4) The manufacture and use of the improved uppiritus herembefore described and
illustrated in the accompanying drawing
The 4th
March 1000