Improvements in and relating to the Valves and Valve-gear of Steam Engines.
Year: 1889

page_text: Date of Application, 29th Oct., 1889-Accepted, 30th Nov., 1889
COMPLETE SPECIFICATION.
Improvements in and relating to the Valves and Valve-gear of
Steam Engines.
IJEROME WHEELOCK, of 25 Elizabeth Street Worcester, Massachusetts, 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:-
My invention relates to automatic cut-off engines, and more especially to engines
such as that described in the Specification of former Letters Patent granted to me
and dated 22nd September A.D. 1885, No. 11,295 and now commonly known as the
Wheelock engine."
An important feature of my said invention is the provision of simple and efficient
means for operating the valves in the cylinder-casting.
My said invention, moreover comprises an improved method of operating the trip
cams or controlling the operation thereof, and other improvements hereinafter set
forth.
In the accompanying drawings I have shown how my said invention may be con-
veniently and advantageously carried into practice.
Figure 1 is a side elevation, partly in vertical section, of the steam cylinder of an
automatic cut-off or "Wheelock" engine, illustrating the relative position of the
valve-seats within the cylinder casting as arranged according to the first part of my
improvements.
Figure 2 is a transverse section, drawn to an enlarged scale, of the valves and
valve-seats contained in one end of the cylinder.
Figure 3 is a rear elevation showing the levers and link whereby the said valves
are operated.
Figure 4 is a plan of the plug or shell and valve removed from the cylinder.
Figure 5 is a plan, drawn to an enlarged scale of the cut-off valve, the lugs and
link whereby said valve is operated being shown in section.
Figure 6 is a transverse section on line a, a Figure 5 drawn to a still further
enlarged scale.
Figure 7 is a vertical longitudinal section showing my improved link block herein-
after described.
"
Figure 8 is a transverse section on the line y, y Figure 7.
Figure 9 is a side elevation showing the said automatic cut-off or " Wheelock
engine with my improved means for operating the cut-off valves applied thereto.
Figures 10, 11 and 12 are diagrams showing the positions which the trip-cams
assume under different relative positions of the eccentric and governor.
Like letters indicate corresponding parts throughout the drawings.
A is the steam cylinder, B is the stop valve, C is a chamber in the cylinder-casting,
into which the steam is admitted through the valve B and which is provided at both
ends with cut-off valves D and valve-seats plugs or shells D', whereby steam may be
admitted through passages E E' into either end of the cylinder A. F is the exhaust-
valve and F the seat thereof, through which the steam, after it has performed its
duty in the cylinder, is permitted to pass into the exhaust pipe F2, substantially as
described in my said former specification.
The construction of the cut-off valves D and their seatings D₁ is shown more
clearly in Figures 2, 4, 5 and 6; the valve-seat or shell D₁ is provided at its
extremities with heads a, a; the head a is provided with a nose or bearing & through
which extends one end of the shaft or spindle c for operating the valve; the other
end of the said shaft is supported in another bearing in the head a'. To the said
shaft or spindle c and close to the heads a, a¹ arc attached, by means of set-
screws d, cranks e by means of which the valve D is reciprocated through the

page_text: medium of links f which are coupled to the said valve by means of pins passed
through the said links and through lugs formed on the valve. It will be
readily understood that an oscillating motion of the shaft or spindle c will cause a
reciprocating motion of the valve D upon its seat D¹.
Heretofore dash-pots have been employed for cushioning or checking the closing
inovement of the cut-off valves, and it has heretofore been deemed impracticable to
use such valves without dash pots. I find that the movement of my improved
valve can be effectually checked or cushioned without the aid of a dash-pot. I
therefore dispense with the dash-pot and provide the following means for checking
and controlling the movement of the valve, that is to say - is a spring secured
at one end to the smaller head a of the taper plug or shell D¹ and bearing at
its other end against the inside of the valve-bore or hole for the said plug in the
cylinder-casting, when the plug is fitted into its proper place in the said casting.
If the valve D is opened and subsequently released, the said spring / will cause
a quick sliding motion of the said valve and thus close the same, the motion of
the valve being checked by the lugs striking against projections or cams i
provided on the under-side of the cranks e, so that the valve will always close
rapidly and fully and come to the same position. a result which cannot be attained
by the action of the dash-pot hitherto employed on account of the air-cushion in
the
спр of the latter.
The exhaust-valves are constructed and arranged to operate in a substantially similar
manner to the cut-off valves above described.
In Figure 1, I have shown springs which may be substituted for, or used in com-
bination with the springs h. Each of the shafts or spindles e has fixed thereon an
arm to the extremity whereof is attached a rod which extends through a lug
secured to the cylinder A, and is provided with an adjustable collar m; against this
collar bears one extremity of a spiral spring n, the other extremity of which bears
against the said lug. The compression of the spring n can be regulated by simply
adjusting the said collar m upon the rod in the required direction.
I
As it is of great importance to preserve an accurate fit of all the parts connected
with the valve-operating mechanism and more especially concerning the links, I
provide each pair of lugs 7 with a taper hole (as more clearly shown in Figure 5)
adapted to receive a taper pin o which is driven tightly into its place and thus
prevented from rotation. The pin o is flattened or cut away at o' to correspond with
the inside of a steel bushing p also formed with a taper hole and having a projection
or feather p which corresponds to the flat or cut away portion of the said pin › so as
to prevent rotation of the said bushing thereon. I provide, moreover, in the link fa
steel taper bushing which is driven into a corresponding hole in the said link and
thus forms a solid connection with the same. As the outside of the bushing p and
the inside of the bushing are turned parallel and of the same diameter, an accurate
fit is obtained, and, in case of wear, either or both of the bushings may be removed
and new ones substituted therefor without the necessity for discarding either the valve
or the link for that reason.
The links are curved or bent as shown more clearly in Figure 2 to permit them to
pass over the shafts or spindles c without coming in contact with the said shafts or
spindles when the valves are closed.
In Figure 3 is illustrated the manner of actuating the valves, and it will be seen
that, in the arrangement of the several parts shown in this Figure, no deviation from
that described in my said former specification has been made with the exception of a
difference in the construction of the latch-block as more clearly shown in Figures 7
and 8.
is the latch-block which is held by means of the bolts in sliding contact with the
under surface of a projection upon the link as more clearly shown in Figure 3,
is a bolt which passes transversely through the said latch-block and to one extremity
of which is attached the arm of the cut-off valve, while its other extremity supports
one end of the spring rod k, so that the strain on the bolt is practically equalized and
the objection arising from a one-sided pull, is obviated.

page_text: An important difference between my present invention and that described in my said
former specification is the drilling of the holes for the bolts and through the latch-
block so that they intersect each other (as shown more clearly in Figures 7 and 8),
and the cutting away of a portion of the bolt to permit the passage of the link-
bolts, whereby lateral and rotary movements of the bolt are prevented and a locked
combination of latch-block, valve-arm, and spring is obtained.
The arrangement of the crank and link heretofore adopted requires an amount of
space which is, in some instances, difficult to obtain, and, in order to cause a full
travel of the valve, the crank must necessarily be long, so that the length of the link
between centres has heretofore been but slightly greater than that of the crank itself,
and the action of drawing the valve open frequently results in too close proximity
between shaft and lugs, so that, on the return movement of the valve, the latter is
forced down upon its seating and breakages sometimes occur in consequence. By
arranging the cranks e to travel through an are at the side of the shaft c opposite to
that on which the lugs g are situated, I obviate this difficulty and am enabled to
employ a link of a length double, or nearly double that of the crank so that an easy
motion of the valve D is obtained and all parts may be placed within the shell or
plug D without overcrowding.
may be placed centrally (or approximately so) upon the
valve in relation to its width so that lifting of the rear part of the said valve due to
the overhanging of the lugs is obviated.
Furthermore the lugs
Another important feature of my present invention is the provision of novel
means for disengaging the link from the latch-block attached to the arm of the
cut-off valve.
The parts have heretofore been so arranged that. the link could not be disengaged
from the latch-block except at certain points of its stroke or travel, by reason of the
trip-cam being stationary during the full stroke of the piston, when the engine is
running at comparatively uniform speed.
For instance, assuming that the engine is running so slow that the governor does
not cause the trip cams to liberate the cut-off valve even at the farthest point of
travel of the valves, and that steam is admitted into the cylinder for almost the full
stroke of the piston, if any "load" on the engine should be suddenly removed, the
cut-off valve cannot be tripped during the return movement of the exhaust-valve
crank, and the acceleration in speed would necessarily be such as to disturb the even
movement of the fly-wheel, which, in some cases, is very detrimental to machines
driven by the engine, for example, to dynamo-electric machines for electric lighting
which require uniform and unvarying speed.
I overcome this objection, according to my present invention, by an improved
system of operating the trip-cams.
Referring to Figures 9 to 12, G is the engine-frame, in the forward end of which is
supported the crank-shaft H carrying the excentric I, which, through the strap J,
excentric rod J' and links J2, imparts oscillating motion to arms K on the shafts or
spindles e of the exhaust-valve F. To the arms K are pivoted the links which are
arranged to be raised out of engagement with the latch-blocks by means of trip-
The cam L is
cams L, L (Figures 10, 11 and 12), pivoted on the valve-spindles c.
provided with teeth which are geared with corresponding teeth on the hub of a
lever M pivoted on a stud fixed in the shell or plug D. The cam L¹ is formed
directly on the hub of the lever M'. The levers M, M are connected by means of a
rod or link M. The excentric strap J is coupled by a link O with a lever P pivoted
at P to the frame G and coupled by means of a link Q to a bell-crank lever R.
S is the engine-governor, the balls of which, by their centrifugal or centripetal
force, cause the rise or fall of the rod T which supporis, with a capability of adjust-
ment, a cross-head U arranged to slide in guides Û¹ secured to, or formed integrally
with the bottom plate U of the oil-reservoir of the said governor S. The bell-crank-
lever R is pivoted to the cross-head U and its lower extremity is in direct connection
through the links M2 with the levers M, M¹.

page_text: In Figure 9 the governor is represented in its lowest position; the piston may thus
obtain full steam from the cominencement of the stroke until the cut-off valve is
tripped, which heretofore could only be accomplished during the forward movement
of the arm attached to the exhaust valve. This would allow full steam for the piston
for fully three-fourths of the stroke, and, if the engine should not require that amount
of steam, a sudden start on the part of the piston would be the result, and the steam
could not be shut off by reason of the arm of the cut-off valve being connected to the
slow-moving arm of the exhaust-valve.
By my improvements I provide for positively disengaging the arm of the cut-off
valve at any point not exceeding three-fourths of the stroke, thus allowing the steam
to expand and carry the piston to the end of its stroke.
The operation of the above described mechanism is as follows, viz.:-The shaft H
when rotated, imparts rocking or oscillating motion to the lever P, which in turn
operates the bell-crank-lever R, thereby causing a rocking motion. of the trip-cam-
levers M, M', the amount of movement of which is always constant, but the location
of which, that is to say, the position they will occupy when at either end of their
stroke or movement, is regulated or determined by the governor S, as will be readily
seen by referring to Figures 11 and 12, in which the excentric is in the same position
in both instances, whilst the cross-head carrying the bell-crank-lever R is in its highest
position in Figure 11, and in its lowest position in Figure 12.
The amount of travel of the said bell-crank-lever R, as indicated by the dotted lines
in Figures 11 and 12, is the same, but the said movement is forward in Figure 12 so
that the trip-cams L, L', upon the slightest action of the governor, may release the
cut-off valve even during the return movement of the exhaust valve-crank.
In Figure 11, these conditions are reversed, inasmuch as the travel of the said
trip-cams L, L, is such as to prevent any engagement of the links and the arms of
the cut-off valves, so that the engine is at all times under full control of the governor
and the cut-off valve may be tripped at any point of the piston travel up to three-
fourths of the stroke.
It will thus be seen that, during each revolution of the crank-shaft H, the
trip-cams L, L travel once back and forth and will consequently disengage the link
from the arm of the cut-off valve during either the forward or the return movement
of the exhaust-valve-crank, and at any point where the said trip-cams will encounter
the said links, the latter condition depending solely upon the position of the balls of
the governor.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I wish it understood that I claim:-
First. The combination of a slide-valve and a spring acting directly against the
said valve, substantially as, and for the purpose, set forth.
Second. The combination, with a slide-valve, a rock-shaft provided with a crank,
and a link connecting the said crank and valve, of a cam on the said rock-shaft
whereby the motion of the. slide-valve is checked, substantially as described.
Third. The combination, with a slide-valve. and a spring acting directly against the
said valve, of a positive stop to check the movement of the said valve, substantially as
described.
Fourth. The combination, with a slide-valve, a rock-shaft provided with a crank,
and a link connecting the said crank and valve, of a taper pin firmly secured within
the lugs of the valve, substantially as, and for the purpose, set forth.
Fifth. The combination, with a slide-valve, a rock-shaft provided with a crank, a
link connecting the said crank and valve, and a pin firmly secured within the lugs of
the valve, of a removable bushing constructed substantially as described and held upon
the said pin, as, and for the purpose, set forth.
Sixth. In a slide-valve as above described, the combination of a link having a taper
bushing, with another bushing held stationary upon a pin as described, and.adapted to
be removed therefrom, as, and for the purposes, set forth.

page_text: Seventh. A latch-block with two holes through it at right angles to each other in
combination with a bolt firmly fastened to the operating arm of the cut-off valve, and
with the link-bolt, substantially as, and for the purposes, set forth.
Eighth. The combination, with a slide-valve, link and rock-shaft, of a crank fixed
upon the said shaft and connected by the said link with the valve and arranged to
move through an are on the side of the said shaft opposite to that on which the
connection with the valve is situated, substantially as, and for the purpose, set forth.
Ninth. In mechanism for controlling the cut-off valves of engines, one or more
trip-cams, which complete one forward and backward movement during each revolution
of the crank-shaft, and the position of which, when at either end of their stroke or
movement, is regulated or determined by the engine-governor, for the purpose above
specified.
Tenth. In mechanism for controlling the cut-off valves of engines, the combination,
with one or more trip-cams, of the means substantially as described for imparting to
the said trip-cams a complete backward and forward movement during each revolution
of the crank-shaft, as, and for the purpose, set forth.
Eleventh. The improved mechanism for controlling the cut-off valves of engines,
comprising one or more trip-cams, means for imparting to the same a complete
forward and backward movement during each revolution of the crank-shaft, and a
governor whereby the position of the said trip-cams, when at either extremity of their
movement, is regulated or determined, substantially as, and for the purpose, specified.
Dated this 29th day of October 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.