IMPROVEMENTS IN THE CONSTRUCTION OF PISTONS
Year: 1883

page_text: LETTERS PATENT to William Rowan of 96 York Street Belfast in the
County of Antrim Ireland Engineer for an Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF PISTONS
"
PROVISIONAL SPECIFICATION left by the said William Rowan at the
Office of the Commissioners of Patents on the 6th February 1883.
WILLIAM ROWAN of 96 York Street Belfast in the County of Antrim Ireland.
Engineer "IMPROVEMENTS IN THE CONSTRUCTION OF PISTONS
"
My present invention refers to an invention for which Letters Patent were
granted to me the 23rd May 1877 N° 2013 and particularly to the springs employed
for pressing out the packing rings against the sides of the cylinder. The object of
my present invention is to improve the construction of pistons of this class and to
render them more suitable for large diameters
According to this invention I employ a curved helical spring for pressing the
packing ring apart and outward against the sides of cylinder while at the saine
time its curved middle portion presses against the joint piece or gullet holding it
steam tight against the inside of packing rings. This helical spring may advan-
tageously be made from a cast steel tube cut in the lathe to any pitch required to
suit the form of spring required.
The gullet piece before referred to is preferably made of brass and of ☐ section in
the middle.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Rowan in the Great Seal Patent Office on the 4th August
1883.
WILLIAM ROWAN of 96 York Street, Belfast in the County of Antrim, Ireland,
Engineer "IMPROVEMENTS IN THE CONSTRUCTION OF PISTONS
"
My present invention refers primarily to part of an invention for which Letters
Patent were granted to me the 23rd May 1877 N° 2013.
In the specification of my said patent I described a piston having two packing
rings which were pressed apart from each other and against the junk ring and the
flange of the body of the piston by an intermediate wave shaped ring while the
said packing rings were pressed against the sides of the cylinder by other springs
placed on the inside of the said packing rings. While employing in my present
invention a wave spring for pressing the packing rings apart from each other my
present invention particularly refers to the aforesaid springs employed for pressing
out the packing rings against the side of the cylinder, I thus improve the
construction of pistons of this class and render then more suitable for large
diameters, although they are found to answer equally well for small diameters.
According to this invention I employ a curved helical spring for pressing the
packing ring apart and outward against the sides of the cylinder while at the same
time its curved middle portion presses against the joint piece or gullet holding it
steam tight against the inside of the packing ring. This helical spring is first bent
to the required radius and then at each end connected to or inserted in abutment
pieces or lugs which are rivetted on or otherwise fixed or formed on a thin ring or
hoop, made of steel or iron and either wave shaped as the corresponding ring
described in my aforesaid previous patent specification or plainly circular. This
hoop or ring lies against the inside of the packing ring and is nearly of the same
depth. The helical spring may be made from a cast steel tube cut in the lathe to
any pitch required to suit the strength of spring required, or it may be made by
winding a flat round or other rod of steel or other suitable elastic material round a
mandril in the ordinary manner. A mandril or core is placed inside the belical
spring to keep it in form and position when in the piston. The gullet piece
before referred to is preferably made of L section in the middle.
This description of the improved springs and their action on the packing rings
will be more clearly understood by referring to the accompanying sheet of drawings
in which the same reference letters are used in the several Figures to denote the
same parts. Figure 1 is a plan of a piston one half of which is in section so as to
shew one of the packing rings A with the helical spring B in position, also the hoop
or ring C on which the abutments D D are fixed to carry the helical spring B and
receive the pressure therefrom which pressure is imparted by the hoop to the
packing ring A equally all round its circumference. The joint piece or gullet E
against which the helical spring B presses is also shewn in position in Figures 1. 2.
and 3. Figure 2 is a side elevation of the same piston the right half being in
section shewing both packing rings A. A in section with the flat belical springs B B
against the joint pieces E E. In this section as well as in sections Figures 3 and 5
the joint pieces of both packing rings are shewn together for convenience of
illustration but in practice they break joint with each other in the usual manner.
In Figure 3 the helical springs B B are shewn of round section and partly housed
in the gullets E E though this housing may be confined to the abutment pieces as
sbewn on Figure 1. The wave spring F for pressing the packing rings end wise
against the junk ring and piston flange faces is shewn in Figure 2 in elevation on

page_text: the left hand half of the Figure and in section on the right. This spring is also in
section on Figures 3 and 5 in its position between the two packing rings. In
Figures 2 and 5 the wave spring is shewn as housed or lying in a recess in the
packing rings while in Figure 3 this spring is shewn between the two packing
rings without any housing. The packing ring may be made in either way without
affecting the efficiency of the piston.
In cases where a very small space is allowed for the packing rings the helical
springs may be made to lie close to the packing rings with only the ring C between.
This modification is shewn in Figures 4 and 5 which are respectively a part plan
and sectional elevation. The joint piece E in this modification does not project
beyond the inner diameter of the packing ring and the band which carries the
abutments D D is continued round over the cut in the packing ring until the two
ends nearly meet. The several Figures in the sheet of drawings are illustrations of
a piston having a junk ring but my improvements are also applicable to pistons
without junk rings such as are in use for locomotives and other engines. In such
pistons the packing rings are sprung over the outer diameter of the piston and put
into their respective places by suitable tools, the springs having been previously
placed in position. The wave spring is placed before the second packing ring is
put in and in this form of piston the wave spring is not as in Figure 2 housed
between the packing rings but lies on the space between them as shown in
Figure 3.
For gas motor engines where the pressure acts on one side of the piston only I
may use only one packing ring A and no wave spring F.
Having now particularly described and ascertained the nature of my said
Invention and the manner in which it is carried into effect in practico I have to
state that I do not limit myself to the exact details as shewn in the accompanying
drawings which merely represent the general form in which my invention is
carried out.
What I particularly claim as my Invention is.
:-
First The use in pistons with packing rings of inner rings serving to press the
packing rings against the sides of the cylinder said inner rings being provided with
helical springs for effecting such pressure substantially as described and as illustrated
in the accompanying drawings.
Second-The use in pistons with packing rings of inner rings serving to press
the packing rings against the sides of the cylinder said inner rings being provided
with helical springs for effecting such pressure in combination with a wave shaped
spring placed between the packing rings and serving to press them apart from each
other and against the piston flange and the junk ring or other part of the piston
substantially as described and as illustrated in the accompanying drawings.
In witness whereof I the said William Rowan have hereunto set my hand and
seal this Twentyeighth day of July in the year of our Lord One thousand eight
hundred and eighty three.
TTTTTM DOWA AT