Year: 1888

page_text: Date of Application, 4th Feb., 1888
Specification Accepted, 4th May, 1888
I, WALTER F. BROWN of the City and County of Providence, State of Rhode
Island, U.S.A. Mechanical 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 :-
My invention relates more particularly to Mechanism for automatically recording
the pressure or force exerted against the moving piston of a steam-engine cylinder,
and it consists, essentially, of a metallic spring diaphragm removably secured to the
enlarged head of a tube adapted to directly connect with the engine-cylinder, in
combination with a lover connected with and actuated by the diaphragm, an adjustable
fulcrum for the lever, a paper-carrying cylinder or barrel, and mechanisın constructed,
arranged, and connected with said lever so as to vibrato a pencil point, or tracer, in a
true vertical line.
Heretofore, so far as I am aware, this class of recording-indicators has been
provided with moving pistons and trunks or rods which require packing to prevent
the escape of steam, such construction necessarily producing an excessive amount of
friction as compared with the work required to operate the tracer, the "cards" or
"diagrams" thus produced being proportionately distorted or inaccurate.
The object of my invention is to simplify the construction of steam engine
indicators, thereby at the same time reducing the weight of the reciprocating parts,
and making the machine more compact and symmetrical. Another object attained by
the use of the present invention is that "quick-speed" engines of the present day
may be readily and accurately indicated; the "card" produced thereby being smooth
and free from the wavy or zig-zag line usually produced in making the " expansion
curve." Still another advantage possessed by my improved indicator is that the same
spring-diaphragm, in connection with the adjustable fulcrum of the connected lever, O
is used both for high and low pressures, as well as for intermediate pressures, all as
will be more fully hereinafter set forth and claimed.
In order to illustrate my improved indicator, I have prepared the accompanying
two sheets of drawings, in which-
Figure 1 (sheet 1) represents a vertical sectional view taken through the center of
the indicator, showing the several parts in the normal position. Fig. 2 is a top view

page_text: of the same. Fig. 3 is a perspective view of the movablo fulcrum, detached. Fig. 4
is a similar view of the device for connecting the spring-diaphragm with the main
operating lever. Fig. 5 is a detached view of the fower portion of the_link_which
connects with the free end of the operating-lever. Fig. 6 is a horizontal sectional
view taken through the driving spindle &c., on line of Fig. 1. The last four
Figures being enlarged.
Fig. 7 (sheet 2) is a side elevation of the indicator. Fig. 8 is a detached side
view, in partial section, showing the guide-pulloy for the cord, &c. Fig. 9 is an
enlarged plan view of the pencil-carrying lever, the same being made preferably of
aluminum, and having its bearings lined with steel bushings. Fig. 10 is a side view
thereof, and Fig. 11 is a transverse-sectional view taken on linear of Fig. 10, and
showing the steel bushing.
The following is a more detailed description of the invention and also including the
manner of its construction and general operation.
A, referring to the drawings, designates the improved indicator complote.
H, indicates the pressure-head as a whole, adapted by means of a screw-threaded
tubular end portion e¹ and coupling e², with handles h, to be secured to a cylinder-
cock as usual. The upper portion of said head H, is enlarged to form the diaphragm
chamber, the exterior rim being screw-threaded, and to which is secured the indicator
frame C, the latter having an inwardly projecting rim or flange c', adapted to bear
against packing rings or collars, between which is packed and secured a metallic
spring-diaphragm D. To the center of the diaphragm is secured a fixed fulcrum m
provided with a bar K' secured thereto by screws ... See Fig. 4.
The lower portion of said fulcrum is made cylindrical, terminating in an enlarge-
ment. The same being centrally tapped to receive a screw 8, which passes through
a hole formed in the center of the diaphragm. By means of said scrow and an
interposed collar, d', the diaphragm is rigidly secured to the fulcrum m, and at the
same time producing a steam-tight joint. A comparatively large opening is mado
through the top of the frame C, at its center; the said opening boing tapped and
fitted with an annular nut o, adapted by means of lugs o' to be adjustably mounted
in the frame. This nut, o, serves to limit the movement of the diaphragm in case an
excessive pressure be present in the pressure chamber c. Extending upwardly from
and forming a part of the frame C are oppositely located uprights a³, which support
the base a on which are mounted the drum B and the pencil-carrying mechanism; at
one side the base is extended horizontally and terminatos at its outer end in a vertical
hollow hub a¹ which is bored out to receive a depending hollow spindle w, secured to
or forming a part of the pencil-carrying frame E. An annular-nut screwed to the
lower end of said hollow spindle serving to prevent the latter from vertical move-
ment, but at the same time permitting the frame E to turn freely in its axial
direction.
F, indicates the lever support, or adjustable fulcrum, mounted upon the main frame
or cap Cat right angles to the axis of the drum, &c. and at the opposite side of tho
indicator from the pencil-carrying frame E. A shallow groove is formed in the said
cap into which a tonguo q¹ of the support is fitted. A binding screw e tapped into
the frame C, and passing through an elongated openings, serves to adjustably secure
the support in position. The latter, at its inner end is extended laterally, as at f,
from which project short vertical arms which are slotted to receive a light metallic
clamping-tie K, (Fig. 3) the center portion of which, transversely, is made to
serve as an annular-clamp; the same being bored out to receive the short arm / of the
operating lever L, about to be described. The upper portion of the annular clamp
is provided with a taper-threaded stem b, which is divided throughout its length and
across the face of the clamp, as at 61, thereby, in connection with the nut n, producing
a spring-clamping device adapted to firmly, and also adjustably, retain the lever L
therein. A scale or series of graduated spaces g is formed on the side of the sliding
support F. An index or pointer i is adjustably secured to the frame C adjacent to
said scale, by means of a clamping-screw, which passes through a slotted opening i¹
and is tapped into said frame, see Figs. 1 and 7.

page_text: L, indicates the main operating lever, mounted at the enlargement * upon the
bar K of the fulcrum m; the latter being secured to the diaphragm as before
described. The outer, or free, end of the lever L, is connected to a forked link-end p*,
by means of the thumb-screw p. (Fig. 5, &c.) A link or rod z is mounted to swivel
in the said link-end p*; the rod passes up through the hollow spindle w and is jointed
to and forms a part of the parallel mechanism which imparts movement to the tracer
or pencil t. The arrangement of the levers, &c., to produce a parallel movement, are
well known. As drawn, mand m, designate fixed pivots secured to the pencil-carrying
frame E, see Fig. 1. A horizontal link a jointed to the pivot m³ is connected at its
opposite end with the vertical link m², which in turn is jointed to the link z. A vertical
link m³, is jointed to the other pivot m; the upper ends of these links m³, m³ connect
with the long arm or pencil-carrying lever m². The parts being so arranged that the
centers of the pivots m², the upper joint of the link 2, and the poncil t are always in
line. As drawn, also, the proportions of the links are such as to produce a ratio
of 71, that is to say, the free end of the lever L will produce a travel of the pencil
equal to seven times its own movement. At the samo time the positions of the
fulcrums of the levor L (Fig. 1) are such as to produce a relative movement of
about 3:1, so that if the center of the diaphragm rises one-sixteenth of an inch, the
pencil will be correspondingly raised twenty-one sixteenths. It is obvious, now, that
by loosening the scrow e and nut n, and moving the lever support or fulcrum F
toward the center, and then re-securing the parts in position, that the leverage is
directly increased, thereby adapting the indicntor to be used under different pressures
without changing the diaphragm. By means also of this device, I am enabled to
dispense with a series of springs, thereby saving their cost and the necessary time in
changing them, as is common to piston indicators.
D, indicates the metallic diaphragmn secured to the head H, by means of the annular
nut C, the latter having an inwardly-projecting circular flange c which bears against
a packing-ring interposed between it and the outer edge of the diaphragm, as fully
shown in Fig. 1. The said diaphragm is made of sheet metal, or other metal which
is susceptible of being rapidly vibrated under pressure, without impairing its efficiency.
As drawn the diaphragm is crimped, thereby forming a series of concentric undulations
or corrugations in its surface.
The paper-carrying drum B may be actuated by means of a cord, guide-pulley, &c.,
as usual. A stationary study is tappped into the center of the base-plate a, directly
over the center of the diaphragm. A drum end or head 4, is provided with an
annular hub which is adapted to turn freely on said stud; the outer lower rim of
said head is turned to receive and fit the lower portion of the drum B, (Fig. 1).
A circumferential groover is formed in the base of said head to receive a cord ³, (see
dotted lines Fig. 8) one end of which is secured to the head, and the other adapted
to be attached to reducing and reciprocating mechanism connected with the cross-
head or other suitable parts of an engine as usual. A guide pulley p³, is mounted in
a holder u having a hollow siem u through which said cord passes and leading to
the groove r.
The stem portion u is mounted in fixed split ears . A thumb-
screw tapped therein serving to adjustably secure and clamp the holder in
position.
An upper, or circular head u, is secured to the stationary stud v, said head having
a downwardly-extending flange to which one end of a spiral springs' is attached, as
usual; the other end of the spring being secured to the hub of the drum head
The upper face of the hub of the head u is provided with ratchets r¹, (Fig. 6) which
engage similar ratchets formed on the adjacent face of the top or cap piece n², the
latter being fitted to and surmounting the square upper portion n³ of the stud v. The
lower face of the cap is provided with ratchets adapted to engage those of the
head u.
A bolt passes through the cap n³ and is tapped into said square end
portion of the stud.
In order to adjust the tension of the main or retraction-springs, the bolt n' is first
slackened and the cap n next withdrawn from the ratchets ¹; the drum-head^.is
then turned to the right or left, as desired, thereby.expanding or contracting. the

page_text: spring. After making the desired adjustment or tension to the drum, the cap is
dropped into reengagement with the ratchets, and the bolt n screwed down to prevent
the cap from lifting.
Another feature of the present invention resides in the construction of the links
and joints, constituting the "parallel motion." The several reciprocating levers or
links thereof, as m², m², m³, a², and z, I propose making of aluminum; the hubs 68,
of the several joints to be lined with a thin sleeve or bushing 69, of hardened steel.
By means of this arrangement the weight of the reciprocating parts is greatly
reduced, yet at the same time possessing ample strength and stiffness for the work.
The advantage being that owing to the diminished weight the levers may be operated
at a much greater velocity without serious vibrations than the recording mechanism
of indicators as usually constructed. The steel bushings form very durable bearings
for the steel pins at the several joints.
The operation is as follows:-
The indicator is assumed to be properly connected to the steam engine cylinder,
the cord being attached to a reducing mechanism actuated by the cross-head or
other suitable reciprocating part of the engine; now, upon admitting steam from the
cylinder into the pressure chamber c, the force of the steam acting against the under
surface of the spring-diaphragm forces the center portion of the latter in a vertical
direction, thereby slightly elevating the lever Land causing the pencil-lever m² to
move an increased distance corresponding to the leverages of the parallel mechanism
and the position of the adjustably mounted fulcrum K. A piece of paper is attached
to the drum B as usual. Now, by vibrating the pencil-carrying frame E in its hollow
socket a¹, so as to engage the point of the pencil t with the surface of the paper, the
"card "
combined movements of the drum and diaphragm produces a
or diagram
which may be computed as usual, after the removal of the paper from the drum.
It will be noticed that the lever L in its upward movement is opposed by the torsion
of the steel supporting bar K, thereby dispensing with a loose joint. The short arm
of the lever at the same time being a fixed fulcrum, which is also provided with a
torsion-bar K in lieu of a joint.
"
"
I would state that the said bars K K' are made from steel, preferably, and are
substantially cruciform in cross-section, as indicated in Fig. 1, wherein the bar K¹ is
shown as a fulcrum on which the lever L is mounted. A detached view of the bar
and its supporting frame or holder is clearly represented in Fig. 4. The other fulcrum-
bar, K, is constructed substantially the same as the bar just described, the main
difference being, however, that it is provided with a transversely arranged central
socket adapted to receive and retain the short arm of the lever L. A split screw-
threaded taper stem b, and forming a part of the socket portion, in connection with
the nut n serve to adjustably clamp the bar and lever together. A perspective view
of this bar and its supporting frame (the lever L being omitted) is shown in Fig. 3.
The fulcrum-bars are secured to the respective frames or holders by screws or pins 1³,
as clearly shown in Figs. 3 and 4. By means of this construction the unsupported
portions of the bars K K¹ are permitted to vibrate slightly in a torsional direction in
unison with the movement of the diaphragm. Upon the removal of pressure from
the diaphragm the elasticity of the fulcrum-bars assists in returning the soveral
connected parts to their normal position.
By means of the adjustable stop the diaphragm is prevented from excessive
upward movement, which otherwise might injuriously affect the recording mechanism.
By first approximately knowing the several extreme pressures to be recorded the
fulcrum-carrier F, may be successively adjusted so as to produce cards having sub-
stantially equal heights. The position of the parts as drawn corresponding to the
higher pressures. The extreme lower pressures being usually recorded after the
fulcrum is adjustably secured in the opposite position, thereby producing the greatest
leverage. It will be seen from the foregoing that the one spring-diaphragm used,
answers the purpose of the several tension springs necessitated by piston indicators
in recording like pressures.
My improved indicator will produce a truer record of the action of the steam

page_text: within the engine-cylinder than one having a piston with its necessary connections
and packings, as in the latter case the percentage of working friction in the
indicator itself is much greater than is required to operate the pencil-lever by
means of steam acting upon the diaphragm D.
The indicator A is readily adapted to be tested at any time by simply screwing a
test-gage into the threaded end w³ of the tube.
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. The combination in a steam engine indicator, with a paper-carrying barrel
adapted to be revolved, and recording mechanism arranged to vibrate the tracer in
a vertical line, of a head portion adapted to be secured to a steam-engine cylinder,
and a mounted spring-diaphragm connected with and adapted to actuate said recording
mechanisin, substantially as hereinbefore described.
2. A steam engine indicator having a mounted paper-carrying barrel, recording
mechanisin mounted and arranged to vibrate the tracer, an enlarged head portion
provided with a tubular stem adapted to connect with the engine cylinder, and a
spring-diaphragm secured to said head, and forming a chamber communicating with
the engine cylinder, and also adapted to actuate the recording mechanism, all
constructed, arranged and operating, substantially as hereinbefore described.
3. The combination, with a mounted metallic spring-diaphragm having a main
lover, as L, attached thereto, and an adjustable fulcrum for the lever, of recording
mechanism actuated by the said main lever, and a paper-carrying spring-retractile
drum adapted to revolve by means of a flexible connection attached to a reciprocating
part of the engine.
4. The combination, with a pressure chamber, a metallic spring-diaphragm mounted
therein and an adjustably mounted stop for limiting the motion of the diaphragm,
of an adjustably fulcrumed lever, as L, attached to and moving with the diaphragm,
a recording mechanism jointed to the free end of the lever, and a spring-retractile
drum adapted to carry a paper upon which the diagram is made by said recording
mechanism, substantially as hereinbefore described.
5. A steam engine indicator having a mounted metallic spring-diaphragm, a
paper-carrying drum mounted above the diaphragm, an adjustably fulcrumed lever
attached to said diaphragm and located intermediate thereof and the drum, a recording
device or multiplying mechanism, jointed to the diaphragm lever, and a mounted
hollow spindle vertically supporting said multiplying mechanism, all combined and
operating substantially as hereinbefore described and for the purpose specified.
6. In a steam engine indicator, the combination of a mounted metallic spring-
diaphragm, a multiplying mechanism connected therewith and an adjustable stop for
limiting the movement of the diaphragm, substantially as hereinbefore described.
7. A steam engine indicator having levers and links of its multiplying mechanism
made of aluminum and the bearings thereof lined with steel, substantially as shown
and herein before described.
1001
T