AN IMPROVED ATMOSPHERIC HAMMER, THE RESERVOIR OF WHICH IS USED AS A BLOWER WHEN THE HAMMER 18 AT REST
Year: 1864

page_text: LETTERS PATENT to William Dakin Grimshaw, of Mitcham, in the County
of Surrey, Engineer, for the Invention of "AN IMPROVED ATMOSPHERIC
HAMMER, THE RESERVOIR OF WHICH IS USED AS A BLOWER WHEN THE HAMMER
18 AT REST."
Sealed the 19th July 1864, and dated the 25th January 1864.
PROVISIONAL SPECIFICATION left by the said William Dakin Grimshaw
at the Office of the Commissioners of Patents, with his Petition, on the
25th January 1864.
I, WILLIAM DAKIN GRIMSHAW, of Mitcham, in the County of Surrey,
Engineer, do hereby declare the nature of the said Invention for "AN IM-
PROVED ATMOSPHERIC HAMMER, THE RESERVOIR OF WHICH IS USED AS A BLOWER
WHEN THE HAMMER IS AT REST," to be as follows:-
I construct the framework of the machine hollow and air-tight, so that it
may be employed as a reservoir of the compressed air, and at the back part of
the bed plate I bolt or fix a double air pump driven by a belt or by
gearing. The piston of the said air pump may be worked by a crank or
other suitable contrivance. By the action of the air pump I surcharge
the hollow chambers in the framework of the machine with compressed
air (which may be rarefied or not at pleasure). The hammer head is fitted
on to a piston rod working into an inverted cylinder, with similar arrange-
ments to an ordinary steam cylinder, excepting in the construction of the
cut-off, the valve of which has two additional port holes, which gives the work-
man complete control over the hammer, and enables him to regulate the blow

page_text: at pleasure. The hammer is constructed upon a compound bed plate, there-
fore may be moved backward and forward, and is capable of striking any
required blow upon any particular part of the anvil, or on a series of anvils, or
of plating or bending heavy work, and performing such work as it has
not been hitherto practicable for previously constructed mechanical hammers
to execute. When the hammer is at rest the pump and air chambers
may be employed as a blast or blower for the furnace with considerable
advantage and economy. The blast may be used hot or cold, as may be
required. The hammer is entirely under the control of the workman, both
as to speed and the power of the blow. The speed may be varied from 1 to
500 blows per minute, and its striking force from one to two thousand lbs., or
in accordance with the constructed power of the machine it will do its work
with considerably less consumption of power than is usually employed by steam
hammers.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Dakin Grimshaw in the Great Seal Patent Office
on the 25th July 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
DAKIN GRIMSHAW, of Mitcham, in the County of Surrey, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of January, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Dakin Grimshaw, Her special licence that I, the said
William Dakin Grimshaw, my executors, administrators, and assigns, or such
others as I, the said William Dakin Grimshaw, my executors, administrators,
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 "AN IMPROVED ATMOSPHERIC HAMMER, THE RESERVOIR OF WHICH IS USED AS
▲ BLOWER WHEN THE HAMMER IS AT REST," upon the condition (amongst others)
that I, the said William Dakin Grimshaw, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said Invention,

page_text: and in what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Dakin Grimshaw, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, that is to say:-
I construct the framework of the machine hollow and air-tight, so that it
may be employed as a reservoir of compressed air, and at the back part of
the bed plate I bolt or fix a double-action air pump driven by a belt or
by gearing. The piston of the said air pump may be worked by a crank
or other suitable contrivance. By the action of the air pump I surcharge
the hollow chambers in the framework of the machine with compressed
air (which may be rarefied or not at pleasure). The hammer head is fitted
on to a piston rod connected to a piston working in an inverted cylinder, with
similar arrangements to an ordinary steam cylinder, excepting in the con-
struction of the cut-off. The slide valve has two port holes, and on the
upper part of the valve there are two flaps or sliding blocks, which give
the workman complete control over the hammer and enable him to regu-
late the blow at pleasure. The hammer is either stationary or constructed
upon a compound bed plate, so that it may be moved backward and forward,
and be capable of striking any required blow upon any particular part of the
anvil, or on a series of anvils, or of plating or bending heavy work, and
performing such work as it has not been hitherto practicable for previously
constructed mechanical hammers to execute. When the hammer is at rest
the pump and air chambers may be employed as a blast or blower for the
furnace with considerable advantage and economy. The blast may be used
hot or cold, as may be required. The hammer is entirely under the control of
the workman, both as to speed and the power of the blow. The speed may be
varied from one to five hundred blows per minute, and its striking force from
one to two thousand pounds, or in accordance with the constructed power of
the machine it will do its work with considerably less consumption of
than is usually employed by steam hammers.
power
The manner in which my Invention is to be performed will be clearly under-
stood by referring to the figures and letters on the accompanying Sheet of
Drawings, in which Figure 1 is a vertical section of one of my improved
atmospheric hammers with a stationary bed, and Figure 2 a plan of the slide
valve and cutting-off flaps.
The main framework of the machine consists of the hollow bed a and

page_text: hollow column b, both of which are used as reservoirs of air, and at the top of
the column there are pedestals or bearings c for the driving shaft d to work in,
the shaft being turned by the driving pulley e from any driving power; f repre-
sents the hammer cylinder; g, the hammer piston; h, the hammer piston rod;
i, the hammer head; j, the anvil block; k, the slide valve, having two apertures
or port holes l, m, from back to face; n, the valve rod; o, the cylinder of the
air pump; p, the piston or plunger of the air pump; q, the trunk or hollow
pistod rod; r, the valve box for the pump, having four valves 8, there being a
side pipe s¹ for conveying the air to the chamber a; t represents a pipe and
cock communicating with the said chamber a, which pipe and cock are for the
purpose of tempering or regulating the pressure of the blow of the hammer
by opening or shutting the cock so as to allow the air to escape or to keep it
in, and when the hammer is not in use, the pipe and cock may be employed
for conveying the blast of air. The force of the blow of the hammer can also
be tempered or regulated by moving the weight a³ on the lever of the safety
valve 6. To the back of the driving pulley is fixed the crank pin u, which is
connected to the pump piston p by the connecting rod v, so that as the
driving pulley and crank pin revolve the piston shall work up and down
according to the throw of the crank. The slide rod n is connected by a rod w
to a crank pin a fixed to the friction disc y working on a stud. On the
driving shaft d there is a friction wheel 61, held to the shaft by a key or feather,
so that it can revolve with the shaft and at the same time be moved to and
fro when required by the clutch lever c¹, the said friction wheel being for the
purpose of giving the disc revolving motion when they are in contact with
each other, the number of revolutions of the disc and to and fro motions of
the slide valve k being in proportion to the greater or less distance the wheel
is placed from the centre of the disc, which arrangements enable the speed of
the slide valve, and consequently the speed of the hammer, to be varied with
great facility. At the top of the slide valve there are two flaps or sliding
blocks d¹ for cutting off the air at any particular given time, and thereby
regulating the force of the blow of the hammer, the said flaps being worked
by the screws and rods e¹, or by levers, and the air passage from the air
chambers to the valve is shewn by the small arrows. When the hammer is
placed upon a compound bed plate the anvil or anvils are detached from the
framework, and the lower plate at the bottom of the chamber or reservoir is
jointed by a bolt or swivel to a stationary foundation plate in order that the
hammer may be turned to any required position. The formation of a
reservoir for the compressed air in hollow and air-tight framework enables
the machine to be very compact; but in cases where my improvements have

page_text: to be adapted to old machines with solid framework, I employ one or more
separate or distinct reservoirs for the compressed air; and although I have
shewn only one double-action pump, it is evident that I may use a series
of pumps, and also vary the arrangements, dimensions, and strength
of the machine, in order to adapt it for any description of work to be
hammered.
Having now described the nature and particulars of my said Invention, and
the manner in which the same is to be performed, I desire it to be understood
that in atmospheric hammers I claim,―
First, the system of employing a reservoir between the pump or pumps
and the hammer cylinder for holding the compressed air and forming
the reservoir in the framework of the machine, or making it separate or
distinct from it, and placing the machine either on a single or compound bed
plate.
Secondly, the formation in the slide valve of two port holes passing from the
back to the face, and also the flaps or sliding blocks for cutting off the air from
the valve and regulating the blow of the hammer.
Thirdly, the employment of a friction disc and wheel and lever for varying
the number of the strokes of the slide valve.
Fourthly, the pipe and cock in connection with the reservoir of air
for regulating the blow of the hammer, and for being employed as a blast pipe
when the hammer is not in use, and also the mode of regulating the blow of
the hammer by shifting the weight of the safety valve.
And fifthly, the general arrangement of atmospheric hammers, as all such
improvements are herein described and illustrated in the accompanying Sheet
of Drawings.
In witness whereof, I, the said William Dakin Grimshaw, have here-
unto set my hand and seal, this Twenty-second day of July, in
the year of our Lord One thousand eight hundred and sixty-four.
WILLIAM DAKIN GRIMSHAW. (L.S.)
WILLIAM DAKIN GRIMSHAW. (L.S.)