IMPROVEMENTS IN PISTONS AND PLUNGERS
Year: 1884

page_text: I HENRY LANCASTER of the firm of Lancaster and Tonge of Withington Street
Pendleton near Manchester in the County of Lancaster Engineers do hereby declare
the nature of my said invention for IMPROVEMENTS IN PISTONS AND PLUNGERS to
be as follows:-
My Invention relates to the metallic pistons principally used in steam machinery
and to the plungers used in pumping machinery. In my improved piston the rings
are pressed outward by means of coiled spiral springs which are preferably of such
a length in each case as that when bent into a circular form and placed in position
within the piston the two ends will come together so as to form a circular spring.
When in position the spring presses the piston rings outward. In some cases
I bevel or hollow out the insides of the meeting edges of the rings so that by the
pressure of the spring upon the beveled edges the rings are pressed in opposite
directions against the junk ring and the flange of the piston body. In another
construction the spring presses against flanges on the rings as well as outwardly on
the rings the parts being so proportioned as that when the piston is in place the
coils of the spring are radially compressed.
To facilitate the putting together of the parts and to assist in keeping the spring
in position I prefer to form a groove or hollow extending around the piston block
and serving as a bed or abutment for the spring.
The spring is by preference hardened and tempered so as to be permanently
resilient. More than one spring may be applied to each piston. My invention is
applicable to the pistons of air pumps and to other metallic pistons and to plungers
or rams acting as pistons.
nind this anauth dose of Mah 1001.

page_text: I HENRY LANCASTER of the firm of Lancaster and Tonge of Withington Street
Pendleton near Manchester in the County of Lancaster, Engineers, do hereby
declare the nature of my said Invention for "IMPROVEMENTS IN PISTONS AND
PLUNGERS and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement and accompanying
drawings" :-
"
My Invention relates to the metallic pistons, plungers or rams principally used
in steam machinery but also used in air and water pumps and in other similar
machinery. In my improved piston the rings are pressed outward by means of
coiled spiral springs which are preferably of such a length in each case as that
when bent into a circular form and placed in position within the piston the two
ends will come together so as to form a circular spring.
In order that the nature of my Invention may be well understood I will describe
the same with reference to the accompanying drawings wherein Fig: 1 is a Plan
view of the piston with the top ring or cover removed and Fig: 2. represents a
section taken across the diameter of the Piston on the line A. B. in Fig: 1. In the
said Figures or in Fig: 2 only the piston block or body is formed in. two pieces a
and b. the latter constituting the removable junk ring or covering plate which is
secured to the block a. by means of screws or bolts as is usual or by suitable means.
The parts are so shaped and turned as that an annular space for the packing rings
is left as usual. In this space are mounted the two packing rings c. and d. and the
spring e. The said spring for ordinary purposes may be made of steel wire or rod
steel coiled and hardened and tempered but for sonie purposes the hardening and
tempering may not be necessary and for some purposes the spring may be made of
brass or of phosfor bronze or other suitable metal or alloy. The spring is made
of such a length as that the two ends shall meet together. In the example the two
ends of the spring meet at f. in Fig: 1. A hollow g. is turned upon the piston
block and serves as a bed or abutment for the spring but this is not essential. The
two packing rings are also hollowed to fit the spring In the example the rings are
formed with flanges c¹ d¹ which are made to fit in a suitably steam-tight manner
against the prepared surfaces of the parts a. and b. as is usual. When the parts
are put together the coils of the spring are a little compressed so that the elastic
resistance of the spring tends to press the rings outward in all directions from the
centre of the piston and at the same time to press the two packing rings against
the prepared surfaces on the parts a. and b. The packing rings may be. formed
without the flanges and may be otherwise varied in form. More than one spring
bent into a circular form nay be used in a single piston and if preferred the circular
spring may consist of two or more coiled springs instead of a single spring meeting
end to end as in the example In the cases of " "Locomotive or "solid block
pistons" the piston block that is to say the parts a. and b. might be in one piece
as is usual.
"
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. The combination of parts forming the complete Piston substantially as
and for the purposes set forth and indicated hereinbefore and in and by the
accompanying drawings,

page_text: 2. In a piston the coiled spiral spring s. in one piece or in two or more lengths
for the purpose set forth.
3. In a piston the coiled spiral spring e. compressed diametrically between the
blocks a. b. and the packing rings c and d substantially as set forth.
Dated this 6th day of December 1884.
EDWARD K. DUTTON,
Agent,
41, John Dalton Street, Manchester.