Improvements in Pneumatic-pressure Power Hammers.
Year: 1895

page_text: Date of Application, 9th Feb., 1895
Complete Specification Left 11th Nov. 1895 Accented 21st Dec.
1895
Date of Application, 9th Feb., 1895
Complete Specification Left 11th Nov. 1895 Accented 21st Dec.
1895
Improvements in Pneumatic-pressure Power Hammers.
I, DUGALD CLERK, of Driffold Villa, Manor Hill, Sutton Coldfield, in the
County of Warwick, Engineer, do hereby declare the nature of this invention to be
as follows:-
My invention relates to that class of power driven hammers in which compressed
air is the working fluid, and its object is the simple combination of a gas-engine for
supplying the compressed air and suitable valves for controlling the power stroke
with the power hammer.
My invention comprises an ordinary vertical cylinder power hammer with the
usual upright frame, tup, and anvil. On the side of the hammer cylinder is placed
a gas-engine, single acting, and preferably of the "Otto" type. The outer end of
the gas-engine cylinder is closed in and forms a compressing pump for actuating
the hammer. The valve gear for regulating the blow of the hammer consist
preferably of an equilibrium piston valve, expansion chambers, and by pass reducing
valve, all as hereinafter described.
The gas-engine cylinder is bolted against the hammer cylinder, and is preferably
arranged so that the top end is the explosion end, while the bottom end being
closed in, is used as a compressing pump. A fly-wheel is fixed on to the lower
portion of the hammer frame-work, this fly-wheel being coupled up to the gas-
engine piston in the usual manner, and driven by it. A suitable governor is fixed
on the gas-engine, and this governor is connected by a link to a regulating hand
lever. The aforesaid hand lever is placed in such a position that the person
operating the hammer may get easily at it, and by shifting the position of the
lever, alter the tension of a spring on the governor, and thus alter the speed of
the gas-engine.
The hammer cylinder is closed at both ends, and has working in it a piston
block; the piston block being attached to the piston rod carrying the tup, in the
usual manner. The top side of the hammer cylinder communicates with the com-
pressing pump portion of the gas-engine cylinder by means of a short pipe. On
the top side of the hammer cylinder is placed an equilibrium piston valve chest
and expansion chambers.
The space between the pistons of the equilibrium valve is always in communi-
cation with the top.side of the hammer cylinder and the short connecting pipe
leading to the pump portion of the gas-engine cylinder.
The bottom portion of the hammer cylinder is in communication with a small
reservoir, and this reservoir in turn communicates with a reducing valve fixed on
the side of the short connecting pipe between the two cylinders hereinbefore
referred to.
The equilibrium piston valve chest and expansion chambers are constructed as
follows. The valve portion consists of a short cylinder communicating about its
centre by two parts, one with the upper portion of the hammer cylinder and the
other with the short connecting pipe herein before described. In this cylinder
works a double piston equilibrium valve, the space between the two pistons being
always open to the two ports hereinbefore described. Bolted against the side of
the equilibrium valve cylinder is a box consisting of three or more separate
chambers leading by three or more ports to the aforesaid cylinder. The e ports

page_text: are placed in such a position that they come immediately underneath the bottom of
the bottom piston of the equilibrium valve, and when the piston valve is moved
downward it successively opens these ports to the equilibrium space between the
piston and the two ports communicating with the upper portion of the hammer
cylinder and the short connecting pipe.
Fixed in the side of the hammer frame is a power regulating hand lever, this
lever is coupled by a link to the equilibrium piston valve.
On the pump side of the gas-engine a small nou-return air suction valve is fixed.
The operation of the mechanismn herein before described is as follows.―
The gas-engine is started and the pump side draws in a charge of air. The
power regulating hand lever is placed in such a position that none of the expansion
chambers are open to the space between the pistons of the equilibrium valve. The
total clearance space between the top of the hammer piston and the under side of
gas-engine piston, including all ports and passages, is proportioned so that when
the pump has compressed the air in front of it, preferably to an initial pressure
of 100 lbs. per square inch, it acts on the top of the hammer piston and gives it its
downward stroke. The bottom side of the hammer piston communicates with a
small reservoir, and the capacity of the clearance space and reservoir is proportioned
so that when the hammer has completed its stroke a terminal pressure of say
preferably 20 lbs. per square inch exists in the reservoir; this pressure at once raises
the hammer to its former position as soon as the gas-engine pump side begins to go
back to the beginning of its stroke. A small bye pass reducing valve is fixed on
the side of the short connecting air pipe, and this reducing valve is so loaded that
a small quantity of air snifts past it from the high pressure in the air pipe to the
low pressure in the reservoir. The hammer thus makes a number of blows equal to
the revolutions of the gas-engine. To regulate the force of these blows if the
power regulating hand lever is moved a sufficient distance to place the first
expansion chamber in communication with the top of the hammer, the clearance
space is increased and the initial pressure thus reduced, and as each successive
chamber is put into communication the force of the blow is still further decreased.
The expansion chambers are so proportioned that when all of them are in com-
munication the initial pressure is no greater than that which exists on the other
side of the hammer and thus no blow takes place. The number of blows are
regulated by altering the tension of the governor spring by the hand lever
hereinbefore described.
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MARKS & CLERK,
18 Southampton Buildings, London, E.C., and
13 Temple Street, Birmingham, Agents for the Applicant.
Improvements in Pneumatic-pressure Power Hammers.
I, DUGALD CLERK, of Driffold Villa, Manor Hill, Sutton Coldfield, in the
County of Warwick, 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 :-
My invention relates to that class of power driven hammers in which compressed
air is the working fluid, and its object is the simple combination of a gas-engine for
supplying the compressed air and suitable valves for controlling the power stroke
with the power hammer.
My invention comprises an ordinary vertical cylinder power hammer with the
usual upright frame, tup, and anvil. On the side of the hammer cylinder is placed.

page_text: a gas-engine, single acting, and preferably of the "Otto" type. The outer end of
the gas-engine cylinder is closed in and forms a compressing pump for actuating
the hammer. The valve gear for regulating the blow of the hammer consists
preferably of an equilibrium piston valve, expansion chambers, and by-pass
reducing valve, all as hereinafter described.
One method of constructing a power hammer in accordance with my invention
is illustrated in the accompanying drawings in which
Figure 1 is a sectional elevation through the gas-engine and hammer.
Figure 2 is an elevation from the opposite side of Figure 1 with part of the
valve gear in section.
Figure 3 is a section through the gas-engine valves on an increased scale.
Figure 4 is a section through part of the air valve gear also on an increased
scale.
Similar letters indicate the same parts in all the figures.
The gas-engine cylinder A is bolted against the hammer cylinder B, and is
preferably arranged so that the top end C is the explosion end, while the bottom
end D being closed in, is used as a compressing pump. A fly-wheel E is fixed on
to the lower portion of the hammer frame-work this fly wheel being coupled up to
the gas engine piston F in the usual manner, and driven by it. A suitable
governor G is fixed on the gas-engine, and this governor G is connected by a
link H to a regulating hand lever I. The aforesaid hand lever I is placed in
such a position that the person operating the hammer may get easily at it, and
by shifting the position of the lever, alter the tension of a spring J on the governor,
and thus alter the speed of the gas-engine. This governor G is clearly shown in
Figure 1.
The hammer cylinder B is closed at both ends, and has working in it a piston
block K; the piston block being attached to the piston rod L, carrying the tup M
in the usual manner. The top side the hammer cylinder communicates with the
compressing pump portion D of the gas engine cylinder by means of a short
pipe N. On the top side of the hammer cylinder is placed an equilibrium piston
valve chest O, and expansion chambers P, Q, R.
The space between the pistons o o¹, of the equilibrium valve is always in com-
munication with the top side of the hammer cylinder, and the short connecting
pipe N leading to the pump portion D of the gas engine cylinder.
The bottom portion of a hammer cylinder S is in communication with a small
reservoir, not shown in the drawings, and this reservoir in turn communicates with
a reducing valve Z fixed on the side of the short connecting pipe N between the
two cylinders A and B herein before referred to.
The equilibrium piston valve chest O and expansion chambers P, Q, R, are
constructed as follows:-The valve portion consists of a short cylinder O, com-
municating about its centre by two ports U and V, U with the upper portion of
the hammer cylinder B, and V with the short connecting pipe N hereinbefore
described. In this cylinder O works a double piston equilibrium valve o o¹, the
space between the two pistons o o', being always open to the two ports U and V
herein before described. Bolted against the side of the equilibrium valve cylinder
is a box consisting of three or more separate chambers P, Q, R, leading by three
or more ports to the aforesaid cylinder O. These ports are placed in such position
that they come immediately underneath the bottom of the bottom piston of of the
equilibrium valve, and when the piston valve o' o is moved downward it successively
opens these ports to the equilibrium space between the piston and the two ports Ú
and V communicating with the upper portion of the hammer cylinder and the
short connecting pipe N.
Fixed in the side of the hammer frame is a power regulating hand lever W;
this lever is coupled by a link X to the equilibrium piston valve o o'.
On the pump side D of the gas engine, and situated on the connecting pipe N,
a small non-return air suction valve Y is fixed; this valve is clearly shown in detail
on Figure 4.

page_text: The operation of the mechanism hereinbefore described is as follows.—
The gas engine is started, and the pump side D draws in a charge of air through
the valve Y. The power regulating hand lever W is placed in such a position that
none of the expansion chambers P, Q, R, are open to the space between the
pistons oo of the equilibrium valve and therefore these chambers are not in
communication with either the hammer end B or the pump end D. The total
clearance space between the top of the hammer piston K and the under side of gas
engine piston F, including all ports and passages, is proportioned so that when the
pump has compressed the air in front of it, preferably to an initial pressure
of 100 lbs. per square inch it acts on the top of the hammer piston K, and gives it
its downward stroke. The bottom side of the hammer piston communicates with a
small reservoir, not shown in the drawings, and the capacity of the clearance space
and reservoir is proportioned so that when the hammer has completed its stroke a
terminal pressure of say preferably 20 lbs. per square inch exists in the reservoir,
this pressure at once raises the hammer to its former position as soon as the gas
engine piston F begins to go back to the beginning of its stroke. A small by-pass
reducing valve Z is fixed on the side of the short connecting air pipe N, clearly
shown in detail at Figure 4, and this reducing valve Z is so loaded that a small
quantity of air snifts past it from the high pressure in the air pipe N to the low
pressure in the reservoir.
This reducing valve Z is preferably of the construction shown in Figure 4, viz. a
small spring loaded piston a operating by a sliding wedge b in the reducing valve Z,
the increase in pressure over a predetermined amount causing the piston a to pull
the wedge b along and close the valve Z. Any other well known reducing valve
device may be employed.
The hammer thus makes a number of blows equal to the revolutions of the gas
engine. To regulate the force of these blows if the power regulating hand lever W
is moved a sufficient distance to place the first expansion chamber P in com-
munication with the top of the hammer, the clearance space is increased, and the
initial pressure thus reduced, and as each successive chamber Q and then R is put
into communication, the force of the blow is still further decreased. The expansion
chambers P, Q, R are so proportioned that when all of them are in communication,
the initial pressure is no greater than that which exists on the other side of the
hammer, and thus no blow takes place. The number of blows are regulated by
altering the tension of the governor spring J by the hand lever I hereinbefore
described.
The gas engine is preferably of the "Otto" type, and in Figure 3 a section
through the valves of such an engine is shown. c is a cam actuated exhaust valve,
d an automatic air valve, and e a gas valve operated by the governor G herein-
before referred to. The operation of this type of engine is too well known to
require description.
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. A pneumatic power hammer in which the air pressure is generated by an
engine piston and the power of the blow is varied by varying the clearance space
between the compressing side of the engine piston and the power side of the air
hammer, substantially as herein before described.
2. A pneumatic hammer as claimed in the preceding claim provided with an air
return for lifting the hammer, the air pressure for the air return being obtained in
the manner herein before described.
3. A pneumatic hammer operated by a gas engine arranged and combined
substantially as hereinbefore described.
4. In a pneumatic hammer regulating the force of the blow by interposing
varying clearances by means of a piston or like valve controlling ports leading to
chambers of different capacities substantially as hereinbefore described.

page_text: 5. The improved pneumatic pressure power hammer operated by gas engine
substantially as hereinbefore described with reference to the accompanying
drawings.
DL: th of Nambar 1905
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.