Improvements in and connected with the Pistons and Piston Rings of Gas, Hydrocarbon, Steam, or other Fluid Engines.
Year: 1899

page_text: Date of Application, 25th July, 1899
Complete Specification Left, 25th Apr., 1900-Accepted 20th
Improvements in and connected with the Pistons and Piston Rings of
Gas, Hydrocarbon, Steam, or other Fluid Engines.
I, ALFRED GEORGE MELHUISH, of 20, Hinckley Road, East Dulwich, in the
County of London, Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention consists in cutting a spiral groove as a screw thread upon a
5 piston, or a piston valve and cut or form a piston ring in the form of a spiral
or screw thread shaped spring, which can be screwed or worked into the screw
thread groove cut in the piston. By this means the piston ring is continuous
and may make as many turns upon the piston as may be desired, depending
of course upon the length of the piston & pitch of the screw ring. As will
be seen there are no joints in a ring made and fitted in this manner, and the
elasticity of the ring is much more sensitive
walls against which it presses equably at all parts of its length. In practice
easily conformable to the cylinder
the ring is cut out of a tube, or formed from strip metal as a spring of a larger
dia. than the bore of the cylinder it is intended to fit but inasmuch as it will
close up to a much smaller diameter by twisting it in the required direction
it will readily & easily enter the cylinder and still make contact at every
part of its circumference with the cylinder walls and thus ensure a perfectly
tight and reliable packing without undue friction, and at the same time by
having no joints there are no spaces around the piston that is not actually
closed by the ring. My invention is especially applicable to pistons that have
to pass ports or passages such as in the engine shewn in my previous Patent
No. 9038 of /95, as the obliquity of the piston ring enables it to pass the ports
or passages without catching in same as is the case with ordinary parallely
rranged rings for this reason, therefore it is suitable for rings of piston valves,
ay of steam engines when so used I prefer that the ports be cut obliquely in
he reverse direction. Again, the ring always occupies the same position on
he piston, because the groove in which it is screwed terminates in a dead end
sit were, against which the end of the spring ring abuts.
ng may be readily assembled on the piston I allow the screw groove to run
In order that the
it at one end so that the end of the ring may enter same and be screwed
own the piston without distortion, and I then make a junk ring of such form
at it fits upon the last or top thread which is cut away so that there may be
thin portion to break away when in use, and I leave the junk ring corre-
ondingly widened at this part, in such a manner that it makes contact upon
e top side of an entire thread and at the same time forms a stop or abutment
this end of the ring. Pistons fitted in this manner are more easily assembled
their cylinders, which will not require bell mouthing. Briefly described my
ention consists of in involute spring ring fitted in a corresponding involute
ove cut in the piston, and maintaining ring position by a junk ring with
involute inner edge.
Dated this 9141.

page_text: Improvements in and connected with the Pistons and Piston Rings of
Gas, Hydrocarbon, Steam, or other Fluid Engines.
I, ALFRED GEORGE MELHUISH, of 20, Hinckley Road, East Dulwich, in the
County of London, Engineer, 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 object of my invention is improvements in and connected with pistons
and piston rings of gas, hydrocarbon, steam, or other fluid engines whereby
the piston ring is made to fit the cylinder walls in an equal manner at all parts
and to adjust itself to wear in a sensitive and conformable manner.
My invention will be understood from the following description aided by
the accompanying drawings in which Figure 1 is an elevation of a piston ring
constructed according to my invention. Figure 2 is an elevation of a piston
and junk head. Figure 3 is an elevation of a piston, piston ring, and junk
head combined.
My invention consists in cutting a spiral groove A as a screw thread upon a
piston B, or a piston valve and cut or form a piston ring C, Figure 1; in the
form of a spiral or screw thread shaped ring which can be screwed or worked
into the screw thread groove A cut in the piston B. By this means, the piston
ring C is continuous and may make as many turns upon the piston B as may
be desired, depending of course upon the length of the piston B and pitch of
the screw ring C. As will be seen there are no joints in a ring C made and
fitted in this manner, and the elasticity of the ring C is much more sensitive
and easily conformable to the cylinder walls against which it presses. equably
at all parts of its length. In practice, the ring C is cut out of a tube, formed
from strip metal as a spring of a larger diameter than the bore of the cylinder
it is intended to fit but inasmuch as will close up to a much smaller diameter
by twisting it in the required direction it will readily and easily enter the
cylinder and still make contact at every part of its circumference with the
cylinder walls and thus ensure a perfectly tight and reliable packing without
undue friction, and at the same time by having no joints there are no spaces
around the piston B that are not actually closed by the ring C.
My invention is especially applicable to pistons that have to pass ports or
passages, such as in the engine shown in my previous Patent No. 9038 of 1895,
as the obliquity of the piston ring Cenables it to pass the ports or passages
without catching in same as is the case with ordinary parallely arranged rings
for this reason therefore it is suitable for rings of piston valves, say, of steam
engines; when so used I prefer that the ports be cut obliquely in the reverse
direction. Again, the ring C always occupies the same position on the piston B
because the groove A in which it is screwed terminates in a dead end D as it
were, against which the end of the spring ring abuts.
In order that the ring C may be readily assembled on the piston B, I allow
the screw groove A to run out at one end, so that the end of the ring may
enter same and be screwed down the piston B without distortion, and I then
make a junk ring E of such form that it fits upon the last or top thread which
is cut away so that there may be no thin portion to break away when in use,
and I leave the junk ring E correspondingly widened at this part in such a
manner that it makes contact upon the top side of an entire thread and at the
same time forms a stop or abutment for this end of the ring C. Pistons fitted
in this manner are more easily assembled in their cylinders which will not
require bell mouthing.

page_text: Served, my invention consists of an involute spring ring C fitted
in a corresponding involute groove A cut in the piston B and maintained in
ring position by a junk ring E with an involute inner edge F.
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. Constructing a piston with a screw threaded groove, and fitting in said groove
a correspondingly shaped spring piston ring, as set forth.
2. Constructing a piston with a screw threaded groove, and fitting said groove
with a correspondingly shaped ring having a spring piston ring, holding said
spring ring in position by a junk ring having an involute inner edge to receive
one entire thread of the piston ring, as set forth.
3. The improvements in and connected with the pistons and piston rings of
gas, hydrocarbon, steam, or other fluid engines consisting in forming the piston
ring of an involute spring, fitting a correspondingly shaped groove in the piston
and capable by outward expansion of adjusting itself to the walls of a cylinder
to compensate for wear and ensure a tight and reliable packing, substantially
s set forth.
The 25th day of April 1900
R. CORE GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said Alfred George Melhuish
R. CORE GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said Alfred George Melnich