|
method of manufacture was as follows: "The blanks from which these rings are made are solid ring castings. The first operations were to turn and bore them cylindrically; after this they were sawn almost completely round, leaving only a short piece, which is known as the "bridge," and this is shown in the illustration. The joints are then milled out to form the overlapping parts ; after this the rings are put into a template and faced up so as to make the depth equal all round, and exactly the width of the groove in the piston.  This
operation corrects the unequal depth of ring which would be due to the
metal removed by the saw. The two parts of the ring, where it is split,
tended to come apart the thickness of the saw cut, and this caused the
ring to fit tightly in the groove in the piston. Taking off the superfluous
metal in this way also made the rim tapering ; that is to say, it was somewhat
thicker at the part where it springs from the bridge than it is at the
end. These rings can be fitted into a cylinder very easily, and will yet
keep tight, and the half-lap joints are also practically steam-tight. The
split rings are turned up in a jig similar to that described for the solid
rings ; they are thus made to the form they will assume in the cylinder,
and will be a fit all round without undue pressure at any one part. The
split piston ring has been made for cylinders up to 6 feet in diameter,
and over 200 lbs. to the square inch pressure. It is possible to spring
them over solid pistons from q. inches in diameter up to 6 feet, and they
may be made for use with any existing piston. These rings are made both
for steam engines and internal combustion engines ; for pumping work and
other special operations they are made of brass. They are found to wear
the engine cylinder very evenly all round, so that it remains cylindrical."
"Modern Engines etc"
Rankin
Kennedy, 1903
|