IMPROVEMENTS IN STEAM AND OTHER PISTONS
Year: 1883

page_text: LETTERS PATENT to Alexander Mac Laine of Belfast in the County of
Antrim in Ireland, for an Invention of IMPROVEMENTS IN STEAM AND
OTHER PISTONS
PROVISIONAL SPECIFICATION left by the said Alexander Mac Laine at
the Office of the Commissioners of Patents on the 25th January 1883.
ALEXANDER MAC LAINE of Belfast in the County of Antrim in Ireland
IMPROVEMENTS IN STEAM AND OTHER PISTONS
The object of my Invention is to provide Steam and other Pistons with durable
and efficient elastic metallic packings having a double expansion movement.
For this purpose I fit the Piston with two or more metal rings cut through in
one or more places and with a wave spring or springs inserted between the rings
so as to maintain an efficient pressure and hold the rings tightly in the piston in
the longitudinal direction of the cylinder in combination with which arrangement
I affix a coil or other spring or springs at or near the ends of the rings where cut
so as to press the ends apart and expand the rings circumferentially against the
inner surface of the cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Mac Laine in the Great Seal Patent Office on the
19th July 1883.
ALEXANDER MAC LAINE of Belfast in the County of Antrim in Ireland
"IMPROVEMENTS IN STEAM AND OTHER PISTONS"
The object of my invention is to provide Steam and other Pistons with durable
and efficient elastic metallic packings having a double expansion movement
I for this purpose fit the Piston with two or more metal packing rings which are
cach cut through transversely in one or more places and are provided with a circular
wave spring or other springs inserted between them so as to maintain an efficient
pressure and hold them tightly in the piston in the direction of the longitudinal
axis of the Cylinder in combination with which arrangement I affix a coil or other
spring or springs at or near and across the ends of each metal ring where cut
through so as to press such ends apart and expand the ring circumferentially
against the inner surface of the Cylinder
In some arrangements I construct the packing rings or some or one of them with
flanges at each side so as to form a recess or recesses round the rings for the
reception and enclosure of the wave spring or a series of springs of various
lengths
The packing rings may if desired be prevented from moving round in the piston
by means of pins inserted into the junk ring and body of the piston respectively
and projecting through or into slots or holes in the packing rings the expansion of
which may be provided for by making the slots or boles oblong or oval
I employ the ordinary metallic tongue-pieces for tightening the cuts in the
packing rings and the same may be fitted either on the outside or on the inside of
the rings in a variety of obvious ways.
The junk ring is by preference screwed down so as to compress the circular
wave or other spring or springs placed between the packing rings and to develop
the power of such spring or springs in holding the packing rings tightly against
the junk ring and the body of the piston
The circular wave or corrugated spring is a flat spring and made either a
complete ring or cut through in one place; its diameter may be made less than
that of the cylinder; and the outer flange or flanges constructed on one or more
of the packing rings may be made to fill up the space intervening between the
spring and the cylinder
The coil springs may be either straight or curved and the ends thereof are made
by preference to bear against steel washers which are made of different thicknesses
in order to determine the force of the springs in expanding the packing rings
circumferentially against the inner surface of the cylinder after the packing rings
and coil springs have been compressed therein-and each coil Spring may be main-
tained in position by means of a loose bar or tube passing through it or by studs
projecting into each of its ends and held by lugs or projections formed or fixed
on the packing rings for that purpose
But I do not confine myself to the use of the circular and coil springs herein-
before described inasmuch as the same be varied in character and form in a
number of obvious ways-nor need I employ a bar or tube or studs in connection
with the coil spring or such other spring as I may employ in its stead.
And in order that my said invention may be more fully understood I shall now
proceed to refer to the drawings upon the sheet hereunto annexed, the same letters
of reference indicating the same or corresponding parts of my compound apparatus
throughout all the figures
Fig I is a sectional elevation of a steam piston showing the body of the piston, the

page_text: junk ring and the packing rings with a circular wave or corrugated spring between
them and pins projecting into oblong or oval slots or holes to prevent the packing
rings moving round and also straight coil springs and loose bars or tubes passing
through them into lugs or projections at each end thereof on the packing rings.
Fig II is a plan of a steam piston with the junk ring removed showing one of
the packing rings with a transverse cut therein, a straight coil spring and loose
bar or tube passing through it and steel washers against which the ends of the
spring bear; also a tongue piece on the outside of the cut in the packing ring
Fig III is a sectional elevation of a steam piston showing the same parts as appear
on Fig. 1. adapted to the employment of curved coil springs and studs held by the
lugs or projections on the packing rings
Fig IV is a plan of the parts shown on Fig II but with a curved coil spring and
studs substituted for the straight spring and bar or tube and with the tongue piece
on the inside of the cut in the packing ring and
Fig V is a sectional elevation of one side of a Steam piston showing the packing
rings constructed with flanges both outside and inside so as to form a recess for
the reception and security of the flat spring or a series of springs.
a, a, are the packing rings and a', a', are the ends formed by a transverse cut in
each ring-b, b, are the coil springs affixed at or near and across the transverse
cuts-c, c, c, are the bars or tubes and studs passing through or into the coil
springs b, b-d, is the circular wave or corrugated spring placed between the
packing rings a, a-e, is the junk ring-f is the body of the piston-g, g, g, are
the waves or corrugations of the circular spring d-h, h, are the lugs or projections
upon the packing rings a, a, by which the bars or tubes and studs are held-
k, k, are the steel washers of different thicknesses against which the ends of the
coil springs bear-1, 1, are the pins projecting into the oblong or oval slots or holes
in the packing rings, a, a, to prevent them moving round in the piston-m, m, are
flanges on the packing rings, a, a, and n, is the recess to receive and secure the
spring or springs.
Having now described the nature of my said invention and in what manner the
same is to be performed I would have it to be understood that I do not claim the
exclusive use of transversely cut and flanged or recessed packing rings, circular
wave or corrugated springs and coil springs with bars or tubes and studs, junk
rings, lugs or projections, steel washers and pins except when the same are con-
structed and arranged specially and employed in the manner herein before described
nor do I claim the use of pistons or cylinders nor of any of the separate mechanical
parts which form the compound automatic apparatus employed by me but
I claim,
First The use, in Steam and other pistons, of compound packing rings arranged
with springs to effect a double expansion movement and constructed and
employed substantially in the manner and for the purposes hereinbefore
described and shewn in Figs I, II, III and IV of the drawings hereunto
annexed.
Secondly The use in steam and other pistons of circular wave or other springs
placed between the packing rings and of coil or other springs combined,
constructed and employed substantially in the manner and for the
purposes hereinbefore described and shewn in Figs I, II, III and IV of
the drawings hereunto annexed.
Thirdly The use in steam and other pistons of packing rings constructed with
flanges both outside and inside and employed substantially in the manner
and for the purposes herein before described and shewn in Fig V of the
drawings hereunto annexed.
Fourthly The use in steam and other pistons of flanged or recessed packing
rings arranged with springs to effect a double expansion movement
and constructed and employed substantially in the manner and for the
purposes hereinbefore described and shewn in Fig V of the drawings
hereunto annexed, and,

page_text: Fifthly The combination and arrangement of parts constituting the compound
automatic elastic packings above mentioned constructed and applied
substantially in the manner and for the purposes hereinbefore described
and illustrated by the several drawings on the sheet hereunto annexed
In Witness whereof I the said Alexander Mac Laine have hereunto set my
hand and seal this Eighteenth day of July in the year of our Lord one thousand
eight hundred and eighty three
Signed and Sealed in presence of
HUGH HYNDMAN
Solicitor & Patent Agent Belfast
ALEXANDER MAC LAINE (L.S.)