IMPROVEMENTS IN WORKING HAMMERS BY COMPRESSED AIR
Year: 1860

page_text: LETTERS PATENT to Thomas Geast Dawes, of Wolverhampton, in the
County of Stafford, Iron Merchant, for the lavention of IMPROVEMENTS
IN WORKING HAMMERS BY COMPRESSED AIR."
1000
PROVISIONAL SPECIFICATION left by the said Thomos Geast Dawes at
the Office of the Commissioners of Patents, with his Petition, on
the 20th April 1860.
I, THOMAS GEAST DAWES, of Wolverhampton, in the County of
Stafford, Iron Merchant, do hereby declare the nature of the said Inven-
tion for "IMPROVEMERTS IN WORKING HAMMERS BY COMPRESSED AIR," to be
as follows:-
In working hammers by compressed air according to my Invention,
I take two cylinders, which I connect together at the bottom by a
passage, but not at the top. The cylinders may be of the same size or
one as much larger than the other as required. The one cylinder I call
the hammer cylinder, and the other the motor cylinder for distinction;
they are both fitted with pistons and piston rods. The piston rod of
the hammer cylinder passes through a stuffing box at the bottom of the
cylinder, which is tightly closed, and to the piston rod is attached the
hammer. The top of the hammer cylinder may be either open or closed,
with stop-cocks or valves on the top to admit or expel air, as required.
The motor cylinder is open at the top, and has stop-cocks at the bottom.
Now, supposing the two cylinders to be perpendicular (they may be

page_text: placed in any position or at any angle, as required), and the piston of
the motor cylinder at the top, and the piston of the hammer cylinder
at the bottom, then the descent of the motor piston causes the hammer
piston to rise, and vice versa, and with it the hammer, and either com-
press the air in its cylinder or not, as required, and so on alternately.
1 also, il required, cause the hammer cylinder, to which I fix the
hammer, to work by means of a hollow piston rod connected with the
bottom of the motor cylinder, and which piston rod has an opening
between the top of the hammer cylinder and the fixed piston. In this
airangement the hammer cylinder is closed at top and partly open at
bottom; or if closed at bottom 1 introduce a second tube down the
hollow piston rod connected with the underside of the fixed piston; and
to the top of the said tube or connected with it, I attach stop-cocks or
valves to regulate the admission or expulsion of air to the lower side of
the fixed piston, as required.
By another modification of the same, where a quick speed is required,
I convert the motor cylinder into a blowing tub, and by suitable valves
at the top and bottom passages force condensed air into a receiver,
until by means of a safety valve I find I have sufficient pressure. This
receiver is connected to the hammer cylinder by a passage at the bottom,
which has a suitable valve and also an escape valve, one valve only
being open at a time. These valves I open and close by a suitable
contrivance as quick as the stroke is required, the receiver being supplied
at the same time with the compressed air. 1 also adapt this arrange-
ment to the working of the cylinder, as before explained.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Geast Dawes in the Great Seal Patent Office
on the 19th October 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, 1, THOMAS
GEAST DAWES, of Wolverhampton, in the County of Stafford, Iron
Merchant, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of April, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Geast Dawes, Her special licence that I, the said

page_text: Thomas Geast Dawes, my executors, administrators, and assigns, or
such others as I, the said Thomas Geast Dawes, my executors, admini-
strators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENES IN WORKING
HAMMERS BY COMPRESSED AIR," upon he cudition (amongst others) that 1, the
said Thomas Geast Dawes, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Oflice within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that 1, the said Thomas Gast Dawes, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
In working hammers by compressed air according to my Invention, 1
proceed as follows; I construct two cylinders, which I connect together
at the bottom by a passage. The cylinder to which or to the piston
rod of which the hammer is affixed I call the hammer cylinder, and the
other I call the motor cylinder. I prefer the motor cylinder being of
greater diameter than the hammer cylinder, but I prefer the hammer
cylinder being longer than the motor cylinder. If, for example, the
hammer cylinder be double the length of the motor one, then I prefer
the motor cylinder being five times the area of the hammer cylinder (if
closed at top), but 1 do not confine myself to any particular proportions.
Both cylinders are fitted with pistons and piston rods. The piston rod
of the hammer cylinder passes through a stuffing box at the bottom of
the cylinder, and to the said piston rod is attached the hammer. The
piston rod of the motor cylinder may pass either through the top or
bottom of its cylinder, and the said piston rod is actuated by a crank
or other mechanical contrivance, to which motion is given by steam or
other power.
The motor cylinder is generally open at top, but if
required it may be closed at top and open at bottom, in that case a
passage at the top of the motor cylinder is connected with the passage
at the bottom of the hammer cylinder, or the motor cylinder may be
closed both at top and bottom, by which means two hammers may be

page_text: L
worked by one motor cylinder by connecting its top and bottom passages
respectively with the bottom passages of two hammer cylinders.
aflix inlet and outlet valves to either top or bottom of the motor cylinder,
as required, or to both when both are closed. The top of the hammer
cylinder may either be open or closed, as required; if closed, I affix inlet
and outlet valves to restore the equilibrium of the air, if through
leakage or otherwise this should be required. Or an air receiver may
be fitted to the top, in which case the valves are connected with the
receiver. I also connect an outlet valve with the bottom of the hammer
cylinder, which will regulate the blow of the hammer, or stop it
altogether. But as there is alternately compressed air both above and
below the hammer piston, there is no tendency to disturb the equili-
brium of air, for if in one stroke it escape from one side of the piston
to the other it will in the next stroke escape back again. Supposing
the two cylinders to be perpendicular (one or both may be placed in
any position or at any angle required), and the piston of the motor
cylinder at the top and the piston of the hammer cylinder at the bottom
of their respective cylinders, then the descent of the motor piston
causes the hammer piston to rise, and with it the hammer, and vicc
versa, and either compress the air in the upper part of the hammer
cylinder or not, as required. It is sometimes desirable to make the
hammer strike with blows gradually increasing or decreasing in force.
This may be effected in the following manner-A hollow ball is fixed
on the end of the lever of the outlet valve, at the bottom of the hammer
cylinder, and Hoated on water; the water is allowed slowly to escape
from the vessel, and as the water sinks, the valve will be either opened
or closed gradually, and so cause the hammer to strike a different blow
each time. The inlet valves may be made self-acting or not, as required.
The outlet valves may be opened by hand or by mechanism. I also, if
required, cause the hammer cylinder (to the bottom of which I fix the
hammer) to work by means of a hollow fixed piston rod connected with
the bottom of the motor cylinder. The same modifications as to the
closed top or bottom of cylinder are as applicable to this form of hammer
as to the one herein-before described. The said hollow fixed piston rod
has an opening between the top of the hammer cylinder and the fixed
piston. In this arrangement the hammer cylinder is closed at top, and
either partly open at bottom or closed; if closed, I introduce a tube
down the hollow piston rod connected with the under side of the fixed
piston, and to the top of the said tube, or connected with it, I attach

page_text: inlet and outlet valves to regulate the admission or expulsion of air to
the lower side of the fixed piston, as required.
By another modification of my Invention I substitute for the motor
cylinder a small blowing tub, and by suitable inlet and outlet valves at
the top and bottom of the cylinder, force condensed air into a receiver,
until by means of a safety valve, I find I have sufficient pressure. The
said receiver is connected with the blowing tub by passages at top and
bottom, and to the hammer cylinder by a passage at the bottom; this
passage has a suitable valve. There is also another outlet passage
with an escape valve at the bottom of the cylinder, one valve only being
open at a time. These valves I open and close by any convenient
mechanical contrivance as quick as the stroke is required, the receiver
being supplied at the same time with the compressed air. The escape
valve is connected with a tube which passes into a chimney or other
artificial draught to draw out the air.
I also adapt this arrangement to the working of the cylinder instead
of the piston, as herein-before explained.
My Invention is applicable to all kinds of hammers that are or may
be worked by compressed air, whether the said hammers be used as
forge hammers or for plating, tilting, stamping, rivetting, or for other
purposes.
Having now described the nature of my Invention and the manner of
carrying the same into effect, I wish it to be understood that I do not
limit myself to the precise details herein-before described, as the same
may be varied without departing from the nature of my Invention; but
I claim as my Invention the several arrangements or combinations of
parts herein-before described for working hammers by compressed air.
In witness whereof. I, 'the said Thomas Geast Dawes, have here-
unto set my hand and seal, this Sixteenth day of October, in the
year of our Lord One thousand eight hundred and sixty.
Witness,
THOMAS GEAST DAWES. (L.S.)
RICHARD SKERRETT,
Clerk to George Shaw.