Improvements in Percussive Tools for Caulking Boiler and other Plates and Metal Joints, and for Chipping, Carving, and Boring Metals, Stones, and other Materials.
Year: 1894

page_text: Date of Application, 9th Mar., 1894
Complete Specification Left, 9th Jan., 1895-Accepted, 23rd Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in Percussive Tools for Caulking Boiler and other
Plates and Metal Joints, and for Chipping, Carving, and Boring
Metals, Stones, and other Materials.
1 THOMAS PERCY NELSON of 343 Eccles New Road, Weaste, near Manchester,
in the County of Lancaster, Engineer, do hereby declare the nature of this
invention to be as follows:-
My said invention relates to percussive tools actuated by fluid pressure and
intended to be used for caulking purposes or for chipping metal, dressing castings,
removing scale or incrustation, cutting and carving wood, stone and other materials,
boring rock and for other cognate purposes. My improved tool possesses certain
features of simplicity of construction and improved arrangement which enable it to
he produced more cheaply and to work better and last longer than similar tools of
the ordinary make.
In carrying my invention into effect I cast or otherwise form the cylinder or
body of the tool in one piece with the extension which receives the shank of the
caulking chisel, drift, drill or other appliance, the other end of the cylinder being
closed by a screwed plug which carries the handle which is grasped by the operator.
Within the cylinder, which is of malleable iron or steel, there is a lining of gun
metal, which is bored, and a piston truly turned to fit this bored lining is inserted
therein from the top. A reduced prolongation from the piston plays in the
extension of the cylinder and acts upon the head of the inserted shank of the
caulking chisel or drift. The piston and the lining are so constructed and furnished
with ports and passages that no valves are required to effect the reciprocation of
the piston. For example the piston has a passage cut right through its middle
part and in line with the pressure admission port. This space in the piston com-
inunicates (according to the position of the piston) with ports in the lining on either
side of the piston, which ports lead to the front or the rear of the piston.
The pressure current being thus split, the piston is in equilibrium and is not
pressed unequally against one side of the lining, so that unequal or one sided wear
of the bore and piston is avoided. As the pressure drives the piston to the end of
the cylinder, the fluid pressure is cut off by the covering of the passage in the
piston, and when the piston has reached about the end of its stroke, opposite ports
formed in the end of the piston communicate with holes leading into an annular
port in the back of the lining, which annular port opens into the common exhaust
orifice. The pressure at the back of the piston is exhausted through these ports
and passages, and at the same time the port in the middle part of the piston admits
sufficient pressure to the opposite end or front to constitute a cushion between the
advancing end of the piston and the end of the cylinder. The described cycle of
operations is now repeated to carry the piston back, exactly similar ports and
passages being provided at each end of the cylinder. The prolongation from the
piston plays within the extension from the cylinder and strikes the head of the
inserted chisel, drift, drill or other tool being used. I govern the admission of
the fluid pressure to the cylinder by means of a valve placed in the pressure
admission passage and having its stem connected to a trigger mounted on the
handle or top of the cylinder. This trigger is so arranged that it can be
conveniently controlled by the finger of the hand which grasps the handle on the

page_text: top of the cylinder. The fluid pressure may be of any convenient description, such
for example as compressed air or steam.
My improved apparatus has no internal springs, valves or other fittings to get
out of order, and can be produced at moderate cost.
Dated this 5th day of March 1894
E. K. DUTTON & Co.,
5, John Dalton Street, Manchester, Agents.
COMPLETE SPECIFICATION.
1
Improvements in Percussive Tools for Caulking Boiler and other
Plates and Metal Joints, and for Chipping, Carving, and Boring
Metals, Stones; and other Materials.
I THOMAS PERCY NELSON of 343 Eccles New Road, Weaste, near Manchester,
in the County of Lancaster, Engineer, 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 and accompanying
drawings:-
--
My said invention relates to percussive tools actuated by fluid pressure and
intended to be used for caulking purposes or for chipping metal, dressing castings,
removing scale or incrustation, cutting and carving wood, stone and other materials,
boring rock and for other cognate purposes.
My improved tool possesses certain features of simplicity of construction and
improved arrangement which enable it to be produced more cheaply and to work
better and last longer than similar tools of the ordinary make.
To render my invention more clearly understood I will now proceed to describe
the same more particularly, reference being had to the annexed sheet of drawings,
and to the letters and figures marked thereon.
Figs. 1 and 2 are longitudinal sections upon planes at right angles respectively,
to each other.
Fig. 3 is a cross section at the line A. B Fig. 1 ;
Fig. 4 a cross section at the line CD; and Fig. 5 a section at the line E F.
Fig. 6 is a separate view of the piston.
In carrying my invention into effect, I cast or otherwise form the cylinder or
body of the tool a in one piece with the extension a' which receives the shaft f' of.
the caulking chisel, drift, drill or other appliance f, the other end of the cylinder
being closed by a screwed plug b. A plate may be interposed to cover in the
top of the cylinder but this is not essential. Snugs a² cast on the cylinder carry
the handle c which is grasped by the operator. Within the cylinder a which is ol
malleable iron or steel, there is a lining d of gun metal, which is bored, and a
piston e truly turned to fit this bored lining is insertel therein from the top... A
reduced prolongation e' from the piston plays in the extension of the cylinder and
acts in the manner of a hammer upon the head of the inserted shank f¹ of the
caulking chisel or drift f. The piston and the lining are so constructed and.
furnished with ports and passages that no valves are required to effect the
reciprocation of the piston. For example the piston e has passages e cut right
through its middle part and in line with the pressure admission port g.
Those spaces in the piston communicate (according to the position of the piston).
with ports d' d', d d in the lining on either side of the piston, the ports d' leading
to the front of the piston while the ports d' lead to the rear of the piston.
The pressure current coming through the port g being thus split, the piston is in
equilibrium and is not pressed unequally against one side of the lining so that
unequal or one sided wear of the "bore and piston is avoided. As the pressure:
drives the piston to the end of the cylinder, the fluid pressure is cut off by the

page_text: covering of the passages e in the piston, and when the piston has reached about
the end of its stroke, opposite ports formed in the end of the piston communicate
with holes leading into an annular port d in the back of the lining, which annular
port opens into the common exhaust orifice a³. The pressure at the back of the
piston is exhausted through these ports and passages, and at the same time the
ports in the middle part of the piston admit sufficient pressure to the opposite
end or front of the piston to constitute a cushion between the advancing end of the
piston and the end of the cylinder. This is clearly shown in Fig. 1. The described
cycle of operations is now repeated to carry the piston back, exactly similar ports
and passages being provided at both ends of the cylinder. The prolongation e¹
from the piston plays within the extension a' from the cylinder and strikes the
head of the inserted chisel, drift, drill or other toolf being used. I govern the
admission of the fluid pressure to the cylinder by means of an equilibrium valve h
placed in the pressure admission passage g and having its stem 'connected to a
spring trigger i mounted on the handle car top of the cylinder a. The valve stem
passes through the centre of the stud bolted to the snug a². This trigger i is so
arranged that it can be conveniently controlled by the finger of the hand which
grasps the handle c on the top of the cylinder. The fluid pressure may be of any
convenient description such for example as compressed air or steam.
My improved apparatus has no internal springs, valves or other fittings to get
out of order and can be produced at a moderate cost.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
.
1. The general arrangement, construction and combination of parts composing
the improved percussive tool, substantially as described and as illustrated.
2. A percussive apparatus of the indicated nature consisting of a cylinder having
cast in one therewith a continuation to receive the shank of the tool and containing
a cylindrical hammer piston perforated so as to allow access of fluid pressure to
both sides of the piston and working in a lining in the cylinder so formed with
ports and passages as to allow the piston similarly formed with ports and passages
to reciprocate, without valves or springs, substantially as described and as indicated
in the drawings.
Dated this 8th day of January 1895
E. K. DUTTON & Co.,
5, John Dalton Street, Manchester, Agents.