Improvements in Pistons.
Year: 1894

page_text: Date of Application, 6th Sept., 1894
Complete Specification Left, 6th June, 1895-Accepted, 27th July, 1895
Improvements in Pistons.
We THOMAS DAVIES and SAMUEL DAVIES of Rhostyllen Foundry Wrexham
in the County of Denbigh, Engineers, do hereby declare the nature of this invention
to be as follows:-
The invention relates to pistons in which the packing rings are kept in contact
with the cylinder by means of fluid pressure in the said cylinder. The main
objects are to so improve the construction of such pistons as to render them more
durable and efficient.
Pistons under our invention have the following novel features. The junk ring
and body of the piston are strengthened or made deeper to receive the apertures
for the passage of fluid from the cylinder to the interior of the pistons. The said
junk ring is increased in thickness at one side, and is recessed at the other to
receive set screws or like securing devices. The packing rings or junk ring and
body of the piston are recessed so as to provide a bearing surface for the fluid to
press the said rings against the usual central midfeather or division ring. Packing
rings are made to fit one within the other so as to form a compound packing ring
with divided joint. Two such compound rings may be, and preferably are,
arranged so as to break joint in four places. The midfeather or central dividing
ring is free to rotate or may be fixed if desired. Pins or equivalent devices are
used to prevent the packing rings from rotating.
When pistons are used in horizontal or nearly horizontal cylinders, part of the
lower surface of the body of the piston or junk ring is removed so as to allow
the working fluid to carry the weight of the said piston.
When the lower part of the body of the piston or junk ring is cut away
apertures are made from the side into the fluid space behind the packing rings
to allow any dirt or undesirable matter to pass therefrom into the cylinder.
Dated the 5th day of September 1894.
J. JOHNSON,
Agent.
We THOMAS DAVIES and SAMUEL DAVIES of Rhostyllen Foundry Wrexham,
in the County of Denbigh Engineers, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :--
The invention relates to pistons in which the packing rings are kept in contact
with the cylinder by means of fluid pressure in the said cylinder. The main
objects are to so improve the construction of such pistons as to render them more
durable and efficient.
Pistons under our invention have the following novel features. The junk ring
and body of the piston are strengthened or made deeper to receive the apertures
for the passage of fluid from the cylinder to the interior of the pistons. The said
junk ring is increased in thickness at one side and is recessed at the other to
03

page_text: receive set screws or like securing devices. The packing rings or junk ring and
body of the piston are recessed so as to provide a bearing surface for the fluid
to press the said rings against the usual central mid feather or division ring.
Packing rings are made to fit one within the other so as to form a compound
packing ring with divided joint. Two such compound rings may be and
preferably are arranged so as to break joint in four places. The mid-feather
or central dividing ring is free to rotate or may be fixed if desired. Pins
or equivalent devices are used to prevent the packing rings from rotating
relatively.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is an end view, and Fig. 2 an elevation of a piston part being in section
constructed in accordance with our invention.
a is the main body of the piston. is the junk ring. These parts are
strengthened or made deeper at c to receive the apertures & for the passage of
fluid from the cylinder to the interior of the piston and the said junk ring b is
increased in thickness at one side e, and recessed at the other to receive set
screws to secure it to the body of the piston. 9 central mid-feather or division
ring which may be free to rotate about the body of the piston or be secured
thereto. The packing rings are made in two portions i, i, fitting one within the
other, each being divided diagonally by preference as shown at j, the two divisions
being so placed as to break joint. The two compound packing rings one at
each side of the mid-feather g are arranged to break joint in four places as shown
in the plan. The two portions of each packing ring are kept in proper relative
position by the pins k, and the compound packing rings are also kept in proper
relative position as regards the divisions by the pins l. The outer rings are
recessed as shown at m or the piston body or junk ring is recessed as shown at n to
allow fluid to press the said rings against the mid feather.
When pistons are used in horizontal cylinders part of the lower surface of the
body of the piston or junk ring or both is removed as at o so as to allow the
working fluid to carry the weight of the piston.
When the lower part of the body of the piston or junk ring is cut away
apertures p are made from the side into the fluid space behind the packing rings
to allow any dirt or undesirable matter to pass therefrom into the cylinder.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
First. Pistons having the packing rings acted on by fluid pressure constructed
and operating substantially as herein set forth.
Second. Pistons having the packing rings acted on by fluid pressure with
strengthened or thickened parts to receive apertures substantially as and for the
purpose set forth.
Third. In pistons having the packing rings acted on by fluid pressure, junk
rings recessed and thickened substantially as and for the purpose set forth.
Fourth. In pistons having the packing rings acted on by fluid pressure, compound
packing rings substantially as set forth.
Fifth. Pistons for horizontal cylinders having part of the said pistons removed
substantially as and for the purpose set forth.
Sixth. In pistons for horizontal cylinders having parts of the said pistons
removed downward apertures, substantially as and for the purpose set forth.
Dated the 5th day of June 1895.
J. JOHNSON,
4 Clayton Square, Liverpool, Agent.