An Improved Piston for Steam Engines in which the Spring Rings are Expanded and Revolved by the Steam.
Year: 1892

page_text: Date of Application, 3rd Oct., 1892
Complete Specification Left, 29th June, 1893-Accepted, 9th Sept., 1893
PROVISIONAL SPECIFICATION.
An Improved Piston for Steam Engines in which the Spring Rings
are Expanded and Revolved by the Steam.
PETER THOMSON, Lindsay's Cooperage, Beaverhall, Beaverbank, Edinburgh,
Engineer, do hereby declare the nature of this invention to be as follows
This piston consists of two piston rings, one junk ring, and two spring rings.
No. 1 piston ring is shown in Fig. 1, and in section in Fig. 2: No. 2 piston ring in
Fig. 3, and in section in Fig. 4: the junk ring in Fig. 5, and in section in Fig. 6.
Fig. 9 shows in outline these.three rings in their order of position without being
closed up. Fig. 7 is a side view and Fig. 8 a section of one of the two spring
rings which are shown in position at A. A. Fig. 10, one being between No. 1 piston
ring B and No. 2 piston ring C, and one between No. 2 piston ring and the
junk ring D.
No. 1 piston ring and the junk ring have large holes shown at E. Figs. 1, 2, 5, 6
& 10 to allow the steam to get into the spaces F. F between No. 1 and No. 2 piston
rings, and between No. 2 piston ring and the junk ring. From these spaces the
steam gains access through small round holes G. G. into the annular spaces H. H.
between the spring rings and the raised part of the piston rings, and in this way
presses upon and expands the spring rings making them fit the cylinder tightly.
When one ring is expanded the other is shrunk, thereby reducing the friction to
one-half of that caused by two rings rubbing at the same time.
Near the edge of and through No. 1 piston ring and the junk ring, four small
holes shown at J, Figs. 1 & 5 are bored in a diagonal direction terminating in
semi-circular vanes or grooves K. K. Figs. 1, 2, 5, & 6; and on the sides of the
spring rings next these grooves are similar grooves deepened towards the ends and
terminating in square ends. When the steam enters the cylinder at the beginning
of the stroke it will pass through the diagonal holes J. J. in No. 1 piston ring or
the junk ring, and be conducted by the semi-circular grooves K. K. into the
grooves L. L. in the spring rings and strike against the square ends of them
causing the spring ring to revolve a short distance before the steam passing through
the holes E. E. and G. G. has time to expand them.
The spring rings have another semi-circular groove on their other side shown
at M. Fig. 8 for the purpose of reducing the amount of surface requiring to be
scraped on the sides.
The piston is fixed or bolted on to the piston rod by any of the approved methods
at present in use.
And the improvements and advantages claimed for this my invention are these :-
That by the spring rings being made to revolve a short distance with each stroke of
the piston, they will wear equally all round their circumferences, and both they
and the bore of the cylinder will be kept perfectly circular and steamtight, thereby
saving steam and therefore fuel; and at the same time greatly lessens the repairs
required for the cylinder or spring rings.
Dated this 29th day of September 1892.
חהזח
THOMSON
COMPLETE SPECIFICATION.
An Improved Piston for Steam Engines in which the Spring Rings
are Expanded and Revolved by the Steam.
PETER THOMSON, Lindsay's Cooperage, Beaverhall, Beaverbank, Edinburgh,
Engineer, do hereby declare the nature of this invention and in what manner
Price 8d.

page_text: the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
(The drawings herein referred to are those filed with the Provisional
Specification.)
This piston consists of two piston rings, one junk ring, and two spring rings.
No. 1 piston ring is shown in Fig. 1, and in section in Fig. 2, No. 2 piston ring
in Fig. 3, and in section in Fig. 4, the junk ring in Fig. 5, and in section in Fig. 6.
Fig. 9 shows in outline these three rings in their order of position without being
closed up. Fig. 7 is a side view and Fig. 8 a section of one of the two spring rings
which are shown in position at A. A. Fig. 10, one being between No. 1 piston
ring B and No. 2 piston ring C, and one between No. 2 piston ring and the junk
ring D.
No. 1 piston ring and the junk ring have large holes shewn at E, Figs. 1, 2, 5, 6
and 10, to allow the steam to get into the spaces F. F. between No. 1 and No. 2
piston rings, and between No. 2 piston ring and the junk ring. From these spaces
the steam gains access through small round holes G. G. into the annular spaces H. H.
between the spring rings and the raised part of the piston rings, and in this way
presses upon and expands the spring rings making them fit the cylinder tightly.
When one ring is expanded the other is shrunk thereby reducing the friction to
one-half of that caused by two rings rubbing at the same time.
Near the edge of and through No. 1 piston ring and the junk ring, four small
holes shown at J, Figs. 1 & 5, are bored in a diagonal direction terminating in
semi-circular vanes or grooves K. K. Figs. 1, 2, 5 & 6; and on the sides of the
spring rings next these grooves are similar grooves deepened towards the ends and
terminating in square ends. When the steam enters the cylinder at the beginning
of the stroke it will pass through the diagonal holes J. J. in No. 1 piston ring or
the junk ring, and be conducted by the semi-circular grooves K. K. into the
grooves L. L. in the spring rings and strike against the square ends of them
causing the spring ring to revolve a short distance before the steam passing through
the holes E. E. and G. G has time to expand them.
The spring rings have another semi-circular groove on their other side shown
at M. Fig. 8, for the purpose of reducing the amount of surface requiring to be
scraped on the sides.
The piston is fixed or bolted on to the piston rod by any of the approved
methods at present in use.
And the improvements and advantages claimed for this my invention are these:-
That by the spring rings being made to revolve a short distance with each stroke
of the piston, they will wear equally all round their circumferences, and both they
and the bore of the cylinder will be kept perfectly circular and steamtight, thereby
saving steam and consequently fuel; and at the same time greatly lessens the
repairs required for the cylinder or spring rings.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :
A piston having expanding and revolving spring rings, and that the whole is
constructed substantially in the manner above described, and for the purposes
stated in this my Complete Specification.
Dated this 28th day of June 1893.