Year: 1887

page_text: Date of Application, 2nd July, 1887
Complete Left, 24th Mar., 1888
Complete Accepted, 4th May, 1888
I, SAMUEL SMITH YOUNGHUSBAND of North Road Darlington in the County of
Durham, Engineer, do hereby declare the nature of this invention to be as
follows:-
My Invention relates to valve gear for steam engines, particularly locomotive
engines; and it has for its object to enable a variable travel of the valve and conse-
quently a variable degree of expansion to be obtained without altering the lead, as is
the case with the ordinary reversing link motion which whon notched up to give
expansion, increases the lead; and it has further for its object to enable the engine to
be reversed with a single fast eccentric for each valve motion.
The eccentric rod is connected to the valve spindle connecting rod directly through
a levor and indirectly through an oscillating slot link and connecting rods, the
fulcrum of the said lever being movable and carried by the connecting rod which
works in the oscillating link, so that the motion of the valve due to the to and fro
motion of the eccentric rod in the direction of its length is modified by the oscillating
motion of the slot link due to the varying obliquity of the eccentric rod.
The pivotal centre connecting the end of the eccentric rod to the aforesaid lever, is
carried by a die or slide-block working in a fixed curved guide slot, and the slot link
is mounted to oscillate on a fixed axis situated at the middle of the link and is
provided with an arm normal to the link which is connected with the eccentric rod by
a rod jointed to said lever arm and to the eccentric rod at an intermediate point of its
length which point will, in consequence of the varying obliquity of the eccentric rod,
describe an approximately elliptical path and will by its motion in the direction of the
minor axis of the ellipse, impart an oscillating motion to the slot link. The slot link
is connected with the aforesaid lever by a rod which is pivoted at one end to the said
lever, the pivot forming the fulcrum of the lever, as above mentioned, and at the other
end to a die adjustable in the slot link by means of the ordinary reversing lever.
By means of this arrangement, the link is brought into such position that the engine
may be notched back to shorten the travel of the valve and so vary the expansion,
without altering the lead, when the engine is on the dead centro.
S. S. YOUNGHUSBAND.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: I, SAMUEL SMITH YOUNGHUSBAND of North Road, Darlington, in the County of
Durham, 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 gear for steam engines; and it has for its object to
enable a variable travel of the valve, and consequently a variable degree of expansion
to be obtained without altering the lead as is the case with the ordinary reversing
link motion which, when notched up" to give expansion, increases the lead; and it
has further for its object to enable the engine to be reversed with a single fast eccentric
for each valve motion.
The eccentric rod is connected to the valve spindle through a lever and also through
an oscillating slot link deriving its motion from the angular or sidewise movement of
the eccentric rod, the fulcrum of the said lever being moved to and fro by the
oscillating link in such manner that the motion of the valve due to the motion of the
eccentric rod in the direction of its length is modified by the oscillating motion of
the slot link due to the angular or sidewise movement of the eccentric rod, the extent to
which the one motion is modified by the other depending on the extent to which the
gear is "notched up."
By means of this arrangement, the engine may be notched back at any part of tho
stroke, to shorten the travel of the valve and so vary the expansion without altering
the lead. A further advantage is that the valve opens more quickly the admission
port being full open when the piston has travelled about one eighth or one tenth of
its stroke which is a great advantage in starting a locomotive.
Reference is to be had to the accompanying drawings forming part of this
specification wherein figures 1, 2, and 3 represent different modifications of the
improved valve gear, differing only in detail. The same letters of reference indicate
the same parts in all three figures to which the following description applies
indifferently except otherwise specified. Figures 4 and 5 shew diagrammatic tables,
respectively illustrating the working of the engine in full gear and when notched up
for expansion.
A is the crank shaft and B the single eccentric fast thereon and unlike other
eccentrics placed with its throw in line with, or diametrically opposite to, the crank
instead of being at an angle of about 130° thereto, as usual. C is the eccentric
rod, D. the valve, and E the slot link. F is the lever through which the eccentric
rod, which is connected to its lower end f¹, is connected to the valve spindle
connecting rod d which is connected to the upper end of the lever. G is the
connecting rod whose one end is jointed to a slide block or die working in the slot
link and whose other end is jointed to the lever F at the point which constitutes the
fulcrum of said lever. I is the connecting rod jointed to the eccentric rod at c by

page_text: which the link E is oscillated on its centre by the angular or sidewise motion of the
eccentric rod. The lever F is supported by a radius link I working on a centre,
which in Figures 2 and 3 is for convenience also the axis of the bell crank lover K of
the reversing gear. In Figure 1 the point of connection of the radius link I is at the
lower end of the lever F. In Figures 2 and 3 the point of connection is at f.
In any case this point of support may be carried by a die slido block working in a
fixed guide slot. The link E is mounted to oscillate on a fixed axis e situated opposito
the middle of the slot of the link and is provided with an arm E normal to the link
which is connected with the eccentric rod C by the connecting rod H. In figures 1
and 2 the connecting rod H is jointed to the eccentric rod C at an intermediate point
of its length which point will in consequence of the angular motion of the eccentric
rod C about its end f' as a centro, describe an approximately elliptical path and will
by its motion in the direction of the minor axis of the ellipse, impart an oscillating
motion to the slot link E. In figure 3, which shows one of a pair of engines, the
eccentric rod proper terminates at c but is continued on to the lever F in the form of
a connecting rod C both C and C₁ taking on to the joint pin c which in this case is a
crank pin, being carried by a crank arm L on a rotary shaft the object of this
arrangement being to obtain more vertical motion of the arm E' with the same
horizontal extent of motion of point c. The shaft has a similar crank at its other
end and acted on by the eccentric of the other engine of the pair, the angle of the two
cranks on shaft corresponding to that of the two eccentrics. The lead is determined
by the radial distance of the centres of the lover F, the greater this distance is
made relatively to the distance of the centres ff, the greater will be the lead.
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. A valve gear for steam engines in which the motion of the valve is produced by
the conversion of the rotary motion of a fast eccentric into motion in two directions
approximately at right angles to each other, the said motions acting conjointly (the
one directly and the other through an oscillating link and connecting rod) upon a
lever, whereby the valve is operated in such manner that the gear may be adjusted for
expansive working without altering the lead of the valve and whereby the engine may
be reversed, substantially as specified.
2. The herein described valve gear for steam engines in which the motion of the
valve is produced by the conjoint action of the longitudinal and angular or sidewise
motions of the rod of a single fast eccentric, the first motion being transmitted through
a lever having a movable fulcrum and the second through an oscillating link and
connecting rod acting on the fulcrum of the said lover, the whole combined for
operation, substantially as described.
1
1000