IMPROVEMENTS IN CUSHIONS FOR STEAM CYLINDERS
Year: 1865

page_text: LETTERS PATENT to Frederick Collier Bakewell, of No. 6, Haverstock
Terrace, Hampstead, in the County of Middlesex, for the Invention of
* IMPROVEMENTS IN CUSHIONS FOR STEAM CYLINDERS."-A communication
from abroad by Henry Johnson, of Pittsburgh, United States, North
America.
Sealed the 13th October 1865, and dated the 18th April 1865.
PROVISIONAL SPECIFICATION left by the said Frederick Collier Bakewell
at the Office of the Commissioners of Patents, with his Petition, on
the 18th April 1865.
I, FREDERICK COLLIER BABEWELL, of No. 6, Haverstock Terrace, Hampstead,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN CUSHIONS FOR STEAM CYLINDERS,
follows:-
"
This Invention consists in seating in the cylinder of a steam engine or
steam hammer, and at a short distance from its head, a moveable steain-
tight disc or false head, the steam from the boiler being admitted into the
space between the disc and the fixed bead of the cylinder so as to press the
disc into its seat, and cause it to react against the working piston. An
elastic cushion is thus formed by the pressure of the steam on the moveable

page_text: false head, should the piston be forced against it. This Invention is appli-
cable to the steam cylinder of any steam engine in which the piston works to
and from the cylinder head, but it is especially useful as applied to steam
hammers.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick Collier Bakewell in the Great Seal Patent Office
on the 18th October 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
COLLIER BAKEWELL, of No. 6, Haverstock Terrace, Hampstead, in the County
of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of April, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Frederick Collier Bakewell, Her special licence that I, the said Frederick
Collier Bakewell, my executors, administrators, and assigns, or such others
ns I, the said Frederick Collier Bakewell, 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 Inven-
tion for "IMPROVEMENTS IN CUSHIONS FOR STEAM CYLINDERS," a communication
to me from abroad by Henry Johnson, of Pittsburgh, United States, North
America, upon the condition (amongst others) that 1, the said Frederick Collier
Bakewell, my executors or administrators, by an instrument in writing under
my, or their, or one of their bands and seals, should particularly describe and
ascertain the nature of the said Invention, 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 Frederick Collier Bakewell, 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:—
This Invention consists in seating within the cylinder of a steam engine
or steam hammer, and at a short distance from the end or ends of the cylinder,
a moveable steam-tight disc or false head, the cylinder being lengthend suffi

page_text: ciently to give room for the stroke of the working piston below the disc, tho
steam from the boiler being admitted into the space between the moveable
disc and the fixed head of the cylinder, so as to 'press the disc or false head
into its scat. An elastic cushion is thus formed by the pressure of the steam
on the farther sido of the moveable disc or false head, so that in case the
piston working in the cylinder should strike against the moveable disc
which forms the false head, the steam in the space between it and the fixed
head of the cylinder yields to the blow, and the elastic pressure of the steam
prevents the moveable disc from being forced against the fixed head of the
cylinder. This Invention is applicable to the steam cylinder of any steam
engine in which the piston works towards and from the cylinder head, but it
is especially useful as applied to steam hammers. I shall therefore describo
and illustrate the Invention as applied to that machine.
b
The accompanying Drawing shows a longitudinal section through the steam
cylinder, steam chest, and exhaust pipe of a steam bammer. In the Drawing a is
the steam cylinder, having a piston 6 working steam-tight therein. The piston
rod c passes through a stuffing box in the lower end of the steam cylinder in
the usual manner. On one side of the steam cylinder, and parallel thereto
is situated the steam chamber d, through which steam is admitted into the
cylinder a from the steam chest e by the balance valves f, f', which work as
pistons in the steam chamber; 9 is the pipe which conducts live steam from
the boiler into the steam chest e. The steam chamber d communicates at
the top and bottom with the upper and lower exhaust passages h, h', both of
which open into the exhaust pipe k. The lower exhaust passage h' passes
round or to one side of the neck 1 of the cylinder, through which the piston
rod c works; i, i, are openings from the steam chest c into the steam
chamber d, one i above, and the other below the central piston m on the
balance valve rod p, by which the hammer piston b is worked in its cylinder.
n, n', are the upper and lower steam ports opening from the steam chamber d
into the cylinder a. So far as described there is nothing novel in the con-
struction of the engine. The live steam entering the steam chest e from the
pipe g passes into the steam chamber d through the passage between the
piston m and valve f', and enters the steam cylinder a through the lower
port n', raising the piston and piston rod c, to the lower end of which is
attached the hammer block, in the mode usually practised in the construction
of steam hammers. The exhaust steam escapes at the upper port n above
the valve finto the upper end of the steam chamber d, and passes off through
the passage h into the exhaust pipe k.
hammer is completed it is either forced
When the up-stroke or "lift" of the
down by reversing the position of the

page_text: valves f, f, so as to allow the steam to enter the cylinder a above the piston b,
through the upper port n, and the exhaust steam to escape through the lower
port n', under the valve f, into the exhaust passage h, or the hammer is
suffered to fall by its own weight.
. In the use of steam hammers, as in all straight cylinder steam engines.
there is danger of the piston striking the cylinder head on its up stroke with
such force as to knock it off, and to prevent such an occurence, as well as to
increase the efficiency of the steam hammer is the object of this improvement,
which will now proceed to explain. Instead of terminating the steam
cylinder just above the level of the upper steam port n, at the line X-
9
in the Drawing it is extended above that point, the cylinder head q being
fastened a few inches (more or less according to the size of the cylinder)
above the line where the up stroke of the piston is intended to terminate.
In the steam cylinder a, just above the upper steam port n, a circular disc ris
seated, which is furnished with packing like a piston, so as to make it steam-
tight. The diameter of the steam cylinder above the line X--X is
somewhat greater than it is in that part (below the disc r) in which the
piston works, so that the diser cannot descend into the cylinder below the
upper edge of the steam port n. The upper part of the disc r is cylindrical,
or of uniform diameter, while the lower part may be tapering, so as to fit
tightly in its seat. The under side is a plane surface, but the upper side may
be hollowed out so as to form a bowl s, though this is not essential. Between.
the top of the disc and the cylinder head is a cylindrical space t, into one
side of which opens the steam pipe u, which communicates directly with the
boiler, and at the opposite side of the space the steam pipe g is inserted,
which conducts the steam to the steam chest e, so that the live steam from
the boiler passes to the steam chest of the engine through the space t and
above the disc r, upon which it presses with all the force of the steam in the
boiler. The operation of this construction and arrangement is as follows:-
Should the steam be admitted into the steam cylinder a, through the lower
steam port n', with so much force as to cause the piston to strike against and
raise the disc, the steam within the space t immediately resists, and as the
disc fits steam-tight in its seat, the steam from the boiler cannot get below it
into the working cylinder a, and as the force of steam in the space t is greater
than that in the cylinder, and the area of the upper surface of the disc r is
greater than that of the under side of the piston b, the balance of force is in
favour of the disc, which therefore presses the piston back to its place. If the
upward stroke of the piston should be sufficiently strong to raise the disc r so
high in the space t as to close the openings from the steam pipes u and g, the

page_text: steam in the bowls of the disc prevents it from striking the cylinder head in
any event.
Another advantage attending this Invention is, that when the piston is
raised sufficiently to strike the disc and raise it from its seat, the reaction of
the steam in the space t on the upper surface of the disc forces the piston
downwards, and renders it unnecessary to admit steam through the upper port n
on the down stroke of the piston, whereby a great saving of steam is effected.
It will be evident from the description of the Invention that it is applicable
to steam cylinders of various kinds, for whenever the engine is so constructed
that the piston might f forced against the cylinder head, the moveable
disc with the space between it and the cylinder head may be employed,
and will effectually protect the cylinder head from danger. The advan-
tages of this Invention over an air cushion or any contrivance by which
air or other fluid is closely confined in a space at the end of the cylinder are
obvious.
Having thus described this improvement in cushions for steam cylinders,
I claim and desire to secure by Letters Patent, the use of a moveable disc or
independent piston seated in the steam cylinder, above the working piston,
with a steam space between it and the cylinder head, through and into which
the live steam from the boiler is caused to pass on its way into the steam chest
of the engine, for the purpose of forming a steam cushion, and to increase the
efficiency of the steam engine or steam hammer, substantially as berein-before
described.
In witness whereof, I, the said Fred. Collier Bakewell, have hereunto
set my hand and seal, this Eighteenth day of October, in the year
of our Lord One thousand eight hundred and sixty-five.
FRED. COLLIER BAKEWELL. (L.S.)