IMPROVEMENTS IN CUSHIONING THE PISTON AND SLIDE VALVE OF DIRECT ACTING STEAK ENGINES
Year: 1875

page_text: LETTERS PATENT to Jonathan Pickering, of Stockton-on-Tees, in the
County of Durham, Engineer, for the Invention of “IMPROVEMENTS
IN CUSHIONING THE PISTON AND SLIDE VALVE OF DIRECT ACTING STEAK
ENGINES."
Sealed the 21st August 1875, and dated the 18th June 1875.
PROVISIONAL SPECIFICATION left by the said Jonathan Pickering at
the Office of the Commissioners of Patents, with his Petition, on
the 18th June 1875.
I, JONATHAN PICKERING, of Stockton-on-Tees, in the County of
Durham, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN CUSHIONING THE PISTON AND SLIDE VALVE OF DIRECT
ACTING STEAM ENGINES," to be as follows:-
My improvement relates to working direct acting steam engines for
preventing piston and slide valve striking the ends or covers of cylinder
and steam chest, and is supplemental to my Patent dated March 14th,
1874, No. 932, which 'improvement can be used for other purposes where
a reciprocating motion is required. It consists in an arrangement of

page_text: inlet and outlet passages and steam ports for cushioning with steam
pressure the piston and slide valve.
For carrying into effect the cushioning of the slido valve, which is by
preference a cylindrical slide valve, a portion of the ends in the steam
chest is made to receive a piston. This piston is made steam-tight. A
steam passage is brought to the outer ends of each piston, conveying
steam between the cover and piston. The slide valves strikes against
these steam cushioned pistons when moved to and fro by steam pressure.
A similar arrangement in the cylinder prevents the main piston from
striking the cylinder ends, the object of which is to prevent the covers
or ends of cylinders being broken, and to cause direct acting engines to
work without noise.
'
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Jonathan Pickering in the Great Seal Patent
Office on the 17th December 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JONATHAN
PICKERING, of Stockton-on-Tees, in the County of Durham, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of June, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did for Herself, Her heirs and successors,.
give and grant unto me, the said Jonathan Pickering, Her special
licence that I, the said Jonathan Pickering, my executors, adminis-
trators, and assigns, or such others as I, the said Jonathan Pickering,
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
** IMPROVEMENTS IN CUSHIONING THE PISTON AND SLIDE VALVE OF DIRECT ACTING
STEAM ENGINES,” upon the condition (amongst others) that I, the said
Jonathan Pickering, my exccutors or administrators, by an instrument
in writing under my, or their, or one of their hands and scals, should

page_text: 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 Jonathan Pickering, 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:-
My improvements relate to working direct acting steam engines for
preventing the piston and slide valve striking the ends or covers of
cylinder and steam chest. These improvements are supplemental to my
Patent dated March 14, 1874, No. 932, which improvements can be
used for other purposes in cylinders where a reciprocating motion is
required without the use of cranks or levers. It consists in an arrange-
ment of passages and piston for cushioning with steam pressure the
piston and slide valve.
For carrying into effect the cushioning of the slide valvo, which is by
proference cylindrical, a portion of the ends in the steam chest is mado
to receive a piston. This cushion piston is made larger than the
slide valve. A steam passage is brought to the outer end of this cushion
piston, conveying steam between the cover and piston. The slide valve
strikes against these steam cushioned pistons when moved to and fro.
A similar arrangement in the cylinder prevents the main piston from
striking the cylinder ends.
Having explained the nature of my Invention, I will proceed to
describe with reference to the accompanying Drawings the manner in
which the same is to be performed.
. Figures 1, 2, and 3 are sections showing the applications to a direct
acting steam pump.
The same letters and figures of reference indicate the same parts.
At each end of the cylinder A, A, and valve cylinder 1 are enlarged
recesses 2, bored-out to receive the cushion piston 3. This space 2 is in
direct communication with the steam chest 4, with either a pipe or
passage 5, and supplied with full pressure steam. By these spaces being

page_text: larger in area than the piston or the valve striking them, and the
pressure per square inch of area being alike in each case, the cushion
piston 3 will resist the force and momentum of the piston B or the slide
valve, and thus prevent striking the outer covers. The cushion piston 3
also acts the part of a valve in preventing the waste of steam into the 5
spaces A or 1.
Figures 4, 5, and 6 represent sections shewing the application of my
Invention to the cylinder of a steam hammer.
Having now described the nature of my Invention and the manner in
which the same is to be performed, I wish it to be understood that I do 1
not limit myself to the precise details hercin described and illustrated,
as the same may be varied without departing from the nature of my
Invention, but I claim as my Invention, improvements in cushioning
the piston or slide valve of engines worked by steam or compressed air,
substantially as herein-before described and illustrated on the Drawings,
or any mere modification thereof.
In witness whereof, I, the said Jonathan Pickering, have hereunto
set my hand and seal, this Fifteenth day of December, in the
vear of our Lord One thousand eight hundred and seventy-five.
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