Improvements in Horizontal Pistons.
Year: 1890

page_text: Date of Application, 4th Mar., 1890-Accepted, 5th Apr., 1890
COMPLETE SPECIFICATION.
Improvements in Horizontal Pistons.
I, HORACE SEE, a citizen of the United States, residing in the City and County of
New York, and State of New York, United States of America, 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:—
It is well understood that the piston of a cylinder which is disposed in a horizontal
position wears more quickly upon its under portion, or that are of its circumference
which in the mounting of the piston lies below its horizontal diameter, than upon its
upper portion, the weight of the piston as an entirety coming upon its lower semi-
circumference, and in fact coming only upon an are of the same but little in excess of
forty five to sixty degrees upon each side of its vertical diameter.
My invention relates especially to, and is an improvement upon, a horizontal piston
invented by me and constituting the subject matter of United States Letters Patent
No. 365102, dated June 21st 1887, to which reference is to be made for a better
understanding of the features of improvement; but it relates in general and is
applicable to all pistons and kindred discs which play horizontally, or in a plane
slightly inclined from the horizontal, within a cylinder; and its object is the provision
of means for increasing the durability and augmenting the wearing qualities of the
under or wearing surface of the piston, without to any material extent increasing the
weight, and also the provision of means for facilitating adjustment to wear and for
accurately packing the piston.
In my former invention above referred to, a principal feature is the application to a
piston provided with a circumferential follower, of a shoe adapted to the under cir-
cumferential portion of both piston and follower and removable therefrom in the
direction of the length of the cylinder; a further improvement being the provision,
in connection with the shoe and follower, of a circumferential spring-controlled packing
of a special construction.
My present invention relates particularly to the shoe, and to the mode of applying
it to the follower, in order to render possible its very accurate adjustment to compensate
for wear, and to insure the effectual interception of the passage of the steam or other
fluid past the piston in any position of its adjustment.
The foregoing objects I attain by devices represented in the accompanying drawings
and described in this specification the particular subject matter claimed as novel being
hereinafter definitely specified.
In the drawings,
Figure 1 is a central, vertical, side, sectional, elevation through a piston embodying
my improvements, section being supposed in the plane of the dotted line x-x upon
figure 2, and sight being taken in the direction of the arrows upon said line.
Figure 2 is a rear elevational view of a piston embodying my improvements.
Figure 3 is a similar view of the lower portion of the piston, exhibiting the follower
in place but the shoe removed.
Figure 4 is a rear elevational view of the shoe removed from the follower.
Figure 5 is a fragmentary right-hand edge elevational view of that portion of the
periphery of the piston shown in figure 3 which is, on the sheet, abreast the parts
represented in figure 5.
Figure 6 is a top plan view of the right hand upper portion of the shoe of figure 4.
Figure 7 is a right hand end elevational view of the shoe as shown in figure 4.
Similar letters of reference indicate corresponding parts.
In order the better to understand my present improvements it is necessary to describe
the general construction of the patented piston referred to, to which they are applied,
and which is of the following construction :-
A is the piston proper. represented as of conical form and conveniently provided

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with a hub A*. The rear face of the piston is turned off or otherwise conformed to
present three circumferential rearwardly-facing surfaces which are respectively herein
termed the outer shoulder a, the middle shoulder a¹, and the inner shoulder a³. The
planes or faces of these shoulders are preferably parallel.
B is what I term a follower; it being an angular ring of metal, conveniently made
of the form represented in the drawings, that is to say, having a horizontal member b
and a vertical member 6x,-and being adapted for application against the inner and
middle shoulders of the piston. This follower is conveniently secured to the piston by
follower bolts B* which pass through bolt seats 62 in it the said follower, and thread
into the piston as shown. An arc of the under portion of the periphery of the
follower, being an are of that portion of its circumference which is comprised below
its horizontal diameter, is provided with a recess b³, figure 3, to receive an arc-shaped
shoe C, which latter is a right-angularly flanged metal plate composed of an under
member, which is the wearing surface c, and of a lateral member, right angular to said
under member, which is the hack flange, cx, through the medium of which flange the
shoe as an entirety is, by shoe bolts C, which pass through bolt seats c² and thread
into the follower, secured to said follower.
The horizontal wearing surface c of the shoe preferably extends at least as far
forward as the horizontal member b of the follower, so that said follower is as to its
entire recessed portion 3 shod by the shoe, which latter is of circumferential length
equal to the length of the shoe recess in the follower, and preferably of a breadth in
excess of the average breadth of the piston and follower, in order to afford a very
broad bearing surface for the piston.
It will be apparent from a consideration of the foregoing construction that the
shoe can be both removed and applied without unshipping the piston from its
cylinder. This capability for application and removal without unseating the piston
constitutes one of the material advantages of my former invention.
In the fact that it employs all of the foregoing elements of my former invention, my
present invention is identical therewith. In order however to provide for the very
accurate downward radial projection or setting-out of the shoe, to compensate for
wear and for the centreing of the piston when the adjustment has been effected,-I
form both inner extremities of the shoe recess 63 with straight faces, which I term
recess faces, figure 3, each of which is parallel to a plane embracing the vertical
diameter and the longitudinal axis of the piston, and each of which is preferably
flat-faced steel bearing plate ;-and form the inwardly-facing inner extremital portions
of the shoe with corresponding parallel straight faces, which I term the shoe faces c³,
which, as shown in figure 6, are, preferably, plates of steel applied to said under
member of said shoe, and which respectively bear flat against and make tight and
accurate contact with the respective recess faces 6*.
a
From a consideration of the foregoing construction, it will be apparent that a-
considerable radial in or out movement of the shoe can be made without disjunction
of the contact between the respective recess and shoe faces.
Of course, in order to permit of the foregoing outward movement of the shoe, the
seats for the shoe bolts C* are elongated in directions parallel with the vertical
diameter of the piston.
In order to effectually intercept the passage of steam when the shoe has been set
out, I apply and secure to the follower what I term intercepting plates 65, figures 3
and 5, which respectively occupy planes right angular to the axis of the piston or
parallel with its front faces, and which, by overlapping the radial gaps left between
the ends of the recess and the inner ends of the shoe when the shoe is set out,-
effectually intercept the passage of fluid.
In order to provide for a renewal of the wearing surface of the shoe, I find it
convenient to cast or form its peripheral face with a series of raised webs c³, the
surfaces of all of which coincide with and practically form planes of the acting
peripheral face of the shoe, between which webs are cast wearing surfaces c of white
metal or other preferred material.
In connection with the foregoing improvements, I employ, preferably but not

page_text: restrictively, such a packing ring as is set forth in my former pitent, and which is of
the following construction:
Interposed between the outer shoulder a of the piston and both the front face of
the horizontal member b of the follower B and the front face of the wearing surface c
of the shoe C, the said two faces together forming a complete circumferential face
opposing the aforesaid outer shoulder of the piston,-is a packing ring which com-
pletely circumscribes the piston and is composed of a double series of segments D,
each of which series of segments as to the segments which compose it completely
circumscribes the piston as stated, and the segments composing the respective series
of the which said two series are interdisposed so as to break joints, in a manner
which will be understood by a reference to the full and dotted radial lines designating
the intersection of segments, in figure 3. The segments of the outer series are
conveniently loosely attached by pins d to the outer shoulder a of the piston, the said
shoulder and the said segments being correspondingly bored to let in the pins. The
segments of the inner series are similarly loosely secured by pins dx to the segments
of the outer series, the said pins being let into holes correspondingly oppositely bored
into the opposing faces of the seguents of the respective series.
The various packing segments D, considered together as forming a composite
packing ring to the piston, are adapted, as above, to be maintained laterally between
the follower and its shoe and the outer shoulder of the piston. They are maintained
radially outward against the inner walls of the cylinder by the interposition within a
circumferential recess a*,-formed about the piston to the rear of its outer shoulder
by the application of said follower and shoe, of a series of elliptic or other
springs E, or equivalent spring contrivances, which act between the base of said
recess and the inner sides of said segments. The springs are conveniently maintained
in proper circumferential disposition, and prevented from dropping down together,
The
by radial pins e, or kindred stops, erected from the base of the spring recess.
function of the packing rings is to maintain the piston steam, air, or fluid tight
within the cylinder.
It is, of course, preferable that the packing, as such, should completely encircle
or, technically, "circumscribe," the piston. It is apparent, however, that to the
extent of the length of the shoe the packing proper may be dispensed with, and
the shoe proper constitute in effect, and subserve the functions of, a portion of the
packing, and I use the term "circumscribing packing" in the claims subject to this
obvious limitation.
In order more effectually to provide for the interception of steam or other fluid
which might otherwise escape past the joints between the segments of the packing
rings, I provide the corresponding extremities of the segments with overlapping
tongues d², as shown in figures 1, 3, and 5, so that each segment has at one of its
extremities a tongue which overlaps the abutting extremity of the adjoining segment
and is adapted to a recess formed therein.
It is obvious that when the shoe is worn it can be cheaply replaced, and that
it can be readily re-shod or packed upon its wearing surfaces, or be set out by the
interposition of a suitable filling piece between the horizontal member of the follower
and its own wearing surface.
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 :-
:-
1. The combination of a piston, a circumferential follower having a shoe recess
provided at its extremities with recess faces, and a segmental shoe adapted to the
recess of the follower and provided at its extremities with shoe faces conforming to
the recess faces, substantially as and for the purpose set forth.
2. The combination of a piston, a circumscribing packing, a circumferential
follower having a shoe recess provided at its extremities with recess faces, and a
segmental shoe adapted to the recess of the follower and provided at its extremities

page_text: with shoe faces conforming to the recess faces, substantially as and for the purposes
set forth.
3. The combination of a piston, a circumferential follower having a shoe recess
provided at its extremities with recess faces, a segmental shoe adapted to the recess of
the folower and provided at its extremities with shoe faces conforming to the
recess faces, and intercepting plates at the extremities of the shoe and its recess,
substantially as and for the purposes set forth.
4. The combination of a piston, a circumscribing packing, a circumferential
follower having a shoe recess provided at its extremities with recess faces, a
segmental shoe adapted to the recess of the follower and provided at its extremities
with shoe faces conforming to the recess faces, and intercepting plates at the
extremities of the shoe and its recess, substantially as and for the purposes set
forth.
D
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