IMPROVEMENTS IN APPARATUS TO BE EMPLOYED IN CON- NECTION WITH STEAM AND OTHER ENGINES OR MACHINERY FOR ALTERING THE STROKE, TRAVEL, OR LIFT OF SLIDE VALVES, PISTONS, EQUILIBRIUM VALVES. AND OTHER LIKE MECHANISM
Year: 1879

page_text: LETTERS PATENT to Sam Starkey, of the City and County of Lincoln, for the
Invention of "IMPROVEMENTS IN APPARATUS TO BE EMPLOYED IN CON-
NECTION WITH STEAM AND OTHER ENGINES OR MACHINERY FOR ALTERING
THE STROKE, TRAVEL, OR LIFT OF SLIDE VALVES, PISTONS, EQUILIBRIUM
VALVES. AND OTHER LIKE MECHANISM."
Sealed the 18th July 1879, and dated the 26th May 1879.
COMPLETE SPECIFICATION filed by the said Sam Starkey at the Office
of the Commissioners of Patents on the 26th May 1879.
" IMPROVEMENTS IN
SAM STARKEY, of the City and County of Lincoln.
APPARATUS TO BE EMPLOYED IN CONNECTION WITH STEAM AND OTHER ENGINES
OR MACHINERY FOR ALTERING THE STROKE, TRAVEL, OR LIFT OF SLIDE VALVES,
PISTONS, EQUILIBRIUM VALVES, AND OTHER LIKE MECHANISM."
My said Invention consists in the combination and arrangement of mechanism to
be employed in connection with eccentrics, cams, crank pins, and other like con-
trivances of steam and other engines and machinery, for the purpose of altering the
stroke, travel, or lift of the steam valve or valves, or of the piston, or other
equivalent part of the engine or machine in order to obtain a variable expansion by
thus acting on the slide valve or valves, expansion valves, lift valves, combination
of slide and lift valves, or on any other analogous valves, also for obtaining the
alteration of the stroke of the piston when any gas or non-elastic or non-expansive
fluid is employed. The apparatus can be employed for reversing the engine, and
also for shortening the stroke of the piston of a hydraulic pump as the pressure
increases, thus obviating in the latter case the necessity of employing a second
pump of smaller diameter.
The apparatus forming the subject of my said Invention may be actuated, and
the desired results obtained whilst the machinery is in motion or at rest by a hand
lever, or in the former case automatically by being placed in connection with the
governor or other suitable part of the machinery by means of any convenient and
known apparatus for effecting the desired result.
The apparatus is constructed and arranged as follows:-On the main or crank
shaft, or on a counter shaft driven thereby, is mounted a toothed wheel gearing into a
similar wheel carried by a stud fixed in a bar, lever, or link, to which is connected
directly or indirectly the rod, lever, or other contrivance for actuating the mechanism.
The last mentioned wheel gears into another wheel carried by a pin or stud fixed

page_text: in the above mentioned bar or link, and supported by links from a pin carried in a
fixed bracket or other contrivance. This wheel is of sufficient width to admit of
its gearing into a wheel which is carried by the stud or pin in the said fixed
bracket, and which gears into a wheel mounted loosely on the main or crank shaft
or on the counter shaft, as the case may be. The eccentric, cam, crank pin, or other
mechanism to be acted upon is connected to the last mentioned wheel in such a
manner that its relative position with regard to the shaft may be changed by the
partial revolution of the said wheel. When the described arrangement of mechanism
is to be employed for actuating a cam in order to obtain a variable acting surface
the cam is constructed in two or more parts, placed in juxta-position to cach other,
and capable of being opened or closed like a lady's fan. One part is fixed to the
shaft, and to one or more parts is connected the wheel forming the last of the series
in such a manner that when the latter is partially turned the part or parts of the
cam attached thereto is or are moved from its or their normal position, thus
increasing or diminishing the extent of the acting surface of the cam.
+
I will now proceed to refer to the annexed Drawings, in which the apparatus
forming the subject of my said 'Invention is shown in the first four Figures
in connection with an eccentric suitable for actuating the back valve or cut off
valve of a double expansion 'valve, the main valve being worked in the ordinary
manner by its own eccentric. The necessary modifications for adapting it to other
purposes to which it is applicable will be well understood by persons conversant
with such mechanism.
Figure 1 is a plan of the apparatus; Fig. 2, a side view shewing in dotted
lines the position of the arrangement of wheels and eccentric as changed by the
actuation of the lever; and Fig. 3 is a perspective view; Fig. 4 is a side view
of the compound eccentric. The same letters of reference indicate similar parts in
all the said Figures.
A. is the main or crank shaft or a countershaft driven therefrom; B, the toothed
wheel mounted thereon and gearing into the wheel C, carried by a stud D, fixed in
the bar E, having connected therewith the rod or lever F; or the said rod or lever;
if desired, may be attached to any suitable part of the apparatus. The wheel C
gears into the wheel G, carried by the pin H; the wheel G gears into a wheel I
on the stud K, and the wheel I gears into the loose wheel L, attached to the
eccentric M.
The eccentric M, as will be well understood on reference to Fig. 4, partially
revolves within or in connection with the eccentric O, which is caused to revolve
simultaneously with the crank shaft by means of a pin N (on which it rocks) fixed
in a plate P keyed on the shaft or by any other suitable contrivance. The
eccentric O is connected with the expansion valve by means of the ordinary rod.
The action of the eccentric M varies the eccentricity or throw of the eccentric O by
moving its centre anywhere between the limits 1, 2, and thus varies the travel. of
the expansion valve in a corresponding degree. The full lines show the limit of
greatest and the dotted lines the limit of least eccentricity.
The action of the apparatus is as follows:-On the crank shaft being caused to
revolve motion is transmitted from wheel B through the wheels C, G, and I to the
wheel L, which, together with the eccentric M, is thereby caused to revolve in the
When it is necessary
same direction and with the same speed as the crank shaft.
to alter the travel of the valve the bar E is actuated automatically by the governors
or by hand, and a motion independent of that of the crank shaft is thereby trans-
mitted through the train of wheels to the eccentric M, altering its relative position
to the eccentric O, the eccentricity or throw of which latter, and consequently the
travel of the expansion valve being thereby varied. This variation may be effected
when the machinery is at rest by a hand movement of the bar E. It will be
obvious that instead of making the wheel G wide as before described, two wheels,
one gearing into the wheel C, and the other into the wheel I, may be mounted at
any convenient distance from one another on a spindle instead of on the stud H.
The arrangement of mechanism above described may be made to act in a similar

page_text: cam.
manner on an ordinary single valve, thereby obtaining a variable expansion so far
as is practicable with the use of a simple valve, or sufficient motion may be given
to the apparatus through the medium of the bar E or a lever connected therewith,
as to move the eccentric to the same relative position on the opposite side of tho
crank, thus producing a reversion of the engine. In these cases the apparatus may
be made to act direct on a simple main eccentric, but it is preferred to employ the
compound eccentric before referred to, in which case the eccentric O is guided in
its motion by a strip thereon sliding in a groove in the plate P, or vice versa, at
right angles to the crank, so that whilst the angular position of the eccentric is
changed the point of admission of steam remained unaltered. Figures 5 and 6 are
respectively side view and plan of the apparatus in connection with a compound
A is the main shaft or counter shaft driven thereby; O is that part of the
cam which is fixed thereon; and M is a part of the same cam which is loose on the
shaft, and is fast to the last wheel L of the series (shown at L, in Figure 1) in the
same manner as in the case of the inner eccentric herein before described. On
motion being communicated through the train of wheels by any suitable or con-
venient means acting through the rod E, the wheel L, and with it the portion M of
the cam receives a backward or forward motion relative to the shaft A and tho
part O of the cam. By these means the compound cam is caused to open or close in
a manner similar to the action of a lady's fan. Thus the acting surface thereof, and
consequently the duration of its action is increased or decreased accordingly. Two
or more loose portions of the cam can, when desired, be employed for the purpose
of still further increasing the acting surface of the compound cam.
The variable motion required may be transmitted to the valve or other mechanism
to be acted upon by a rod or lever F¹ at the ond or other convenient part whereof
is a friction roller Q carried on a pin H', fixed in the said rod or lever F¹. This
friction roller is sufficiently wide to cover the edge of the compound cam on which
it rests. It is thus, together with the rod or lever F¹, alternately raised and
depressed for periods varying with the increase or decrease of the acting surface of
the compound cam.
Figures 7 and 8 are respectively a side view and end view of the apparatus
arranged in connection with mechanism for the actuation of a crank pin. A is the
main shaft, on which is fastened the plate P, having therein the radial slot R, in
which the crank pin O is free to move; M is a plate free to revolve on the shaft A.
In this plate is a spiral slot S, which receives one end of the crank pin. The plate M
is fast to the fifth or last wheel L of the series (shown at B, C, G, I, and L, in
Figure 1), the wheel B is keyed to the shaft A, and motion is transmitted there-
from to the wheel L through the intermediate wheels C, G, and I in the manner
hereinbefore described and shown in Figures before referred to. When it is desired
to alter the position of the crank pin motion independent of that derived from the
revolution of the shaft is given to the wheel L, and with it the plate M, by hand
or automatically by the action of the governor or by any other desired and suitable
contrivance, the crank pin is thereby caused by means of the spiral slot S to move
in the radial slot R, further from or nearer to the centre of the shaft A, thus
varying the stroke of the crank, and with it the travel of the piston, plunger, or
other mechanism connected therewith. The altered position of the crank pin and
mechanism is indicated by double. dotted, lines in both Figures. By the employ-
ment of my said Invention the objects desired to be attained are effected in a much
nore simple and effectual manner than is the case when apparatus as ordinarily
constructed are used, whilst, at the same time, the amount of friction in working is
reduced to a minimum. The revolution of the eccentric, cam, or other mechanism
being in the same direction as that of the shaft on which they are carried.
Having thus described and ascertained the nature of iny said Invention, and the
manner in which it is to be performed, I would observe in conclusion that what I
consider novel and original, and therefore claim as constituting the said Invention
is,—
The combination and arrangement of the mechanism composed of the wheels
'

page_text: indicated respectively in the annexed Drawing by the letters B, C, G, I, and L,
substantially as and for the purposes hereinbefore described and set forth.
In witness whereof, I, the said Sam Starkey, have hereunto set my hand and
seal, this Twenty second day of May, in the year of our Lord One thousand
eight hundred and seventy nine.
Signed, sealed, and delivered by the
above named Sam Starkey in the
presence of
R. J. WARD,
Sol*,
Lincoln.
SAM STARKEY. (L.S.)