Improvements in Mechanism for Operating Valves of Motive Power Engines Worked by Pressure of Fluid, such as Steam or Com- pressed Air.
Year: 1891

page_text: Date of Application, 17th Jan., 1891
Complete Specification Left, 15th Oct., 1891-Accepted, 21st Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Mechanism for Operating Valves of Motive Power
Engines Worked by Pressure of Fluid, such as Steam or Com-
pressed Air.
I, HERBERT LINDLEY of Sandon Engine Works, St. Simon Street, Salford, in
the County of Lancaster, Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to valve operating mechanism of the class known as release
or trip gear such as usually adopted to operate steam valves of the Corliss or
double beat type, and has for object the construction of mechanism that shall be
comparatively simple and durable and capable of imparting to the valves a more
correct motion than has heretofore been usually obtained except by the use of
complicated mechanism.
For this purpose according to my invention a rod worked by an eccentric and
hereinafter called the eccentric rod is pivotted at the cylinder end to a swinging
arm or link at or about the centre of the length of the cylinder, or the said end of
the eccentric rod may be pivotted to a suitably guided slide block so that the
pivotted part of the eccentric rod will be caused to move in the direction of the
length of the cylinder, either in a slightly curved path or in a straight path
according as it is pivotted to a swinging arm or link or to a slide. As will be
evident a point in this eccentric rod between the pivot at the cylinder end and the
eccentric at the crank shaft end will have an ellipsoidal path, the ratio between the
major and minor axes of which will increase the nearer the point is taken to
the guided or pivotted end. In order to obtain a suitable movement for operating
a valve say of the Corliss or double beat type I connect to the eccentric rod at a
suitable point thereof between the pivot and the eccentric (at a convenient distance
from the pivot) one end of a link; the other end of this link is attached to a
lever forming part of the particular mechanism designed to move or open the
valve and if desired to release the same when required under control of the governor.
The lower end of this link has in the case of a horizontal engine a constant travel
in an approximately horizontal direction during the whole of the period of opening
and closing of the valve. This travel I utilize to operate a disengaging gear
and allow the valve to close at any desired point of the stroke of piston under
control of the governor. This I am able to do even though as in a late cut off,
the valve itself may be, by the action of the mechanism, returning to its closed
position.
To this end I attach to the said link by a pin or pivot a lever with a cam or
wiper or its equivalent the arrangement being such that as the link vibrates the
cam or wiper is also moved. A light connecting link is attached to a pin on the
cam lever and to a moving piece worked from the governor. The cam or wiper is
arranged so as to act on a lever or wiper forming part of a pawl or detent (carried
on a stud or pin on the before mentioned valve lever) in such a manner as to move
the pawl or detent out of gear with its engaging piece, which is fixed on the valve
spindle, the precise moment at which this release takes place depending on the
position of the moving piece worked by the governor, the connecting link from
which to the cam lever will cause the cam or wiper to act sooner or later on the
lever in connection with the detent.
It may in some cases be convenient to use a second motion shaft driven by gearing
from the crank shaft, and fitted with a crank or eccentric, instead of employing an
eccentric on the crank shaft itself; by this means a shorter and stiffer eccentric

page_text: rod can be adopted, besides obviating the use of an eccentric of large throw
such as might otherwise be necessary in order to obtain a suitable form of
ellipsoid.
To work a valve at the back end of the cylinder, the eccentric rod can be
prolonged beyond its pivotted end and thus from a pin at an equal distance from
the pivot to that used for operating the front valve a similar ellipsoid can be
obtained.
To operate the exhaust valves a motion can be obtained either from an eccentric
or crank pin on the second motion shaft where such is used, or from an eccentric
on the crank shaft of the engine.
Dated this 17th day of Jonu 1801
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
+
COMPLETE SPECIFICATION.
Improvements in Mechanism for Operating Valves of Motive Power
Engines Worked by Pressure of Fluid, such as Steam or Com-
pressed Air.
I, HERBERT LINDLEY of Sandon Engine Works, St. Simon Street, Salford,
in the County of Lancaster, 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 valve operating mechanism of the class known as release
or trip gear such as usually adopted to operate steam valves of the Corliss or
double beat type, and has for object the construction of mechanism that shall be
comparatively simple and durable and capable of imparting to the valves a more
correct motion than has heretofore been usually obtained except by the use of
complicated mechanism.
For this purpose according to my invention a rod worked by an eccentric and
hereinafter called the eccentric rod is pivoted at the cylinder end to a swinging
arm or link at or about the centre of the length of the cylinder, or the said end of
the eccentric rod may be pivoted to a suitably guided slide block so that the
pivoted part of the eccentric rod will be caused to move in the direction of the
length of the cylinder, either in a slightly curved path or in a straight path
according as it is pivoted to a swinging arm or link or to a slide. As will be
evident a point in this eccentric rod between the pivot at the cylinder end and the
eccentric at the crank shaft end will have an ellipsoidal path, the ratio between
the major and minor axes of which will increase the nearer the point is taken to the
guided or pivoted end. In order to obtain a suitable movement for operating a
valve say of the Corliss or double beat type, I connect to the eccentric rod at a
suitable point thereof between the pivot and the eccentric (at a convenient distance
from the pivot) one end of a link; the other end of this link is attached to a lever
forming part of the particular mechanism designed to move or open the valve and
if desired to release the same when required under control of the governor. The
position of the point ou the eccentric rod to which the above named link is best
attached, depends chiefly on two considerations viz. first to obtain a sufficiently
flattened ellipsoid figure or path for the purpose required; and secondly the position
of ellipsoid in relation to the position of the lever of the valve mechanism. The
best condition as to the figure and position of the ellipsoid is determined in some
. measure by the design of the cylinder and valve mechanism. The object of the
invention is however well attained with an ordinary Corliss cylinder, when the ratio
of the major and minor axes of the ellipsoid is from 2 to 5:1 and the position such
that a link from the point on the eccentric rod describing the ellipsoid path, to a
lever on the valve spindle gives motion thereto, in the required manner.
example, the mechanism may be arranged so as to nearly fully open the valve with
j
For

page_text: a small angular movement of the crank shaft and eccentric, the increase of opening
for a given angular motion of the shaft rapidly diminishing until the valve may be
full open at or before the period of quickest piston travel, a further angular motion
of the shaft and eccentric then tending to close the valve slowly and accommodate the
diminishing speed of piston travel. The lower end of this link has in the case of a
horizontal engine a constant travel in an approximately horizontal direction during
the whole of the period of opening and closing of the valve. This travel in the
horizontal direction which is much greater than that of the end of the link in a
vertical direction, I utilize to operate a disengaging gear and allow the valve to
close at any desired point of the stroke of piston under control of the governor.
This I am able to do even though as in a late cut off, the valve itself may be, by
the action of the mechanism returning to its closed position.
To this end I attach to the said link by a pin or pivot a lever with a cam or
wiper or its equivalent, the arrangement being such that as the link vibrates the
cam or wiper is also moved. A light connecting link is attached to a pin on the
cam lever and to a moving piece worked from the governor. The cam or wiper is
arranged so as to act on a lever or wiper forming part of a pawl or detent (carried
on a stud or pin on the before mentioned valve lever) in such a manner as to move
the pawl or detent out of gear with its engaging piece, which is fixed on the valve
spindle, the precise moment at which this release takes place depending on the
position of the moving piece worked by the governor, the connecting link from
which to the cam lever will cause the cam or wiper to act sooner or later on the
lever in connection with the detent.
It may in some cases be convenient to use a second motion shaft driven by
gearing from the crank shaft, and fitted with a crank or eccentric, instead of
employing an eccentric on the crank shaft itself; by this means a shorter and
stiffer eccentric rod can be adopted, besides obviating the use of an eccentric of
large throw such as might otherwise be necessary in order to obtain a suitable form
of ellipsoid.
To work a valve at the back end of the cylinder, the eccentric rod can be pro-
longed beyond its pivoted end and thus from a pin at an equal distance from the
pivot to that used for operating the front valve a similar ellipsoid can be obtained.
To operate the exhaust valves I use an eccentric and rod connected to the levers
on the exhaust valve spindles. The eccentric may either be placed on the second
motion shaft or on the crank shaft.
Referring to the annexed drawings
Fig. 1 is a side elevation of a Corliss valve operating and releasing gear con-
structed according to this invention. A is the cylinder, B B' are the steam valves,
and C C¹ the valve spindles, and D D' are valve levers, each riding free on a bush
on the bracket supporting the corresponding spindle C or C¹ or on one of the
spindles themselves. E is a second motion shaft on which is mounted a wheel. F,
driven from the crank shaft by the screw gearing shewn, or in any other convenient
way, and at the same speed as the crank shaft. A crank pin G. on this wheel
serves to give motion to a rod or lever H, (herein called the eccentric rod) which
is supported at the cylinder end on a rocking arm I, pivoted on a stud J fixed to
the cylinder. The rod H is prolonged beyond its support on the arm I to a
point K. K' is a similar point on this lever between the support I and the shaft E.
The path traced by each of these points K, K¹ is a flattened ellipsoid. tapering
towards I, and shewn in the figure by a dotted line. The upper half of the
ellipsoid has a greater curvature than the lower half due to the motion of the
rocking support I. One of these ellipsoids viz., that produced by the point K, will
be slightly more curved than the other, but when the fulcrum of the rod H is
carried by a slide instead of a rocking arm I, the two ellipsoids will be alike.. The
slight difference in curvature of the two ellipsoids produced in the first case is
however not disadvantageous in practice. In order to operate the steam valve B,
I provide a pin D" on the valve lever D and another pin on the rod H at the
point K, these pins being connected by a link L. A similar arrangement is provided

page_text: for working the valve B from the point K¹. It will be seen that as the
rod H moves through its travel and the point K describes its ellipsoid path, the
valve lever D will be moved by the link L the amount of such motion depending
partly on the position of ellipsoid, partly on the curvature of the upper convex
form of the same, and partly on the vibration of the link L itself. When the
point Karrives at that portion of the ellipsoid where a circle struck from the
centre of the pin D' is a tangent to the convex surface of the ellipsoid, the valve
will be at its greatest opening and beyond this point will commence to close again.
In order to effect the opening of the valve B from the motion of the lever D
I provide on this lever a pin M on which is pivoted a pawl or detent N, and on
the valve spindle I secure a catch piece O. These are shewn to a larger scale in
Fig. 2 where the same lettering applies. Supposing the pawl N to be in engage-
ment with the catch piece O it will be evident that as the lever D is moved
upwards the valve spindle will be rotated with it, and partake of the same angular
motion.
In order to release the valve spindle and catch piece O from the lever D and
pawl N, I provide on the link La pin P, on which is centred or pivoted a cam
or wiper Q. This cam or wiper in the example shewn, consists of a pin carried by
a lever Q which, by means of a pin Q, can be connected to a moving piece Q³
under the control of the governor. The cam Q is arranged so as to engage with
the curved extension R of the pawl or detent N. Supposing the pawl N to be in
engagement with the catch piece O on the valve spindle, and the valve to be open,
the piston having made a portion of its stroke, and supposing the position of the
lever Qmoved by the governor is such that the cam Q is just in contact with the
curved extension R of the pawl, the pin Q2 of the lever Q1 being held stationary
by reason of its being attached to the aforesaid piece Q³ moved by the governor,
then it is evident that a further movement of the link L in the direction of the
arrow, will also move the pin P in the same direction, and the cam Q will press
on R and release the catch piece O from the detent N. The valve spindle being
then left free will be closed by a spring in the usual way. A dash pot S is
provided to bring the valve gently to rest and prevent shock."
In order to work the exhaust valves I provide an eccentric on the boss of wheel F,
which I connect by means of links and levers to the exhaust valve spindles in a
manner now well understood and clearly shewn in the drawings.
In cases where it is not thought desirable to employ gearing to operate the second
motion shaft E, I swing the eccentric rod H at one end on a pivot on the cylinder
in the same manner as previously described and at the other end on a similar pivot
on the bed as shewn in Fig. 3. The rod H thus moves parallel to itself but in a
curved path, due to the rocking of the levers on which it is supported. In this
case the rod H is connected to a second rod H' carried by pivoted arms I I¹ which
are arranged in relation to each other as shewn so that the upper end of one is
turning in a downward direction whilst the other is turning in an upward direction.
By this means I provide a path for the pivots K, K' at the lower ends of the
links L, similar in form to those shewn in Fig. 1 as far as concerns their acting
portions. The return path for the pivots K, Kis however the same as the forward
one which is used to operate the valves, but this does not affect the operation of
the gear in any important degree. In this arrangement I use an eccentric on the
crank shaft T to give the longitudinal travel to the rod H, a second eccentric on
the crank shaft being provided to operate the exhaust valves.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is :-
:-
1. In a Corliss or similar valve gear, the combination with a swinging eccentric
rod H, of a link L and lever D adapted to operate a valve substantially in the
manner described with reference to Figs. 1 and 2 of the drawings.
2. In combination with a link L and lever D such as referred to in the preceding

page_text: claim, a detent N, catch piece O, and cam or wiper Q, the whole arranged and
operating substantially as described with reference to Figs. 1 and 2 of the
drawings.
3. In a Corliss or similar valve gear, a swinging eccentric rod, such as H,
mounted on a lever I and operated by crank pin G substantially as described with
reference to the arrangement illustrated in Fig. 1 of the drawings, for operating
the valve mechanism as set forth.
Doted this 15th doer of October 1901
W. LLOYD WISE,
Per James G. Stokes,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.