Year: 1886

page_text: I, ROBERT RICKIE, of the Cawnpore and Achnera State Railway, Fatehgarh,
North Western Provinces, India, 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, that is to say :—
My said Invention relates to valve gear of the kind deriving its movements from
the piston-rod crosshead or slide block and the connecting rod; and my object is
to simplify the construction of the gear and to contrive it so as to give an equal
distribution of the steam or motive fluid to both ends of the cylinder of a steam
engine or similar motor. My improved valve gear is reversible in its complete
form, but modifications of it are also applicable to motors which do not require to
reverse.
One modification of my improved valve gear is shown in figures, 1, and 2, on
the accompanying sheet of explanatory drawings, figure, 1, being a sectional plan
and figure, 2, a sectional side elevation. Another modification is shown in figures, 3,
and 4, which are a side elevation and a transverse vertical section.
My improved valve gear as shown in figures, 1, and 2, is designed for the arrange-
ment of cylinder and valve in which the valve rod, 5, and piston rod, 6, are parallel
to each other in a plane at right angles to the plane passing through the piston
rod, 6, and crank shaft, 7; but by the introduction of one or more rocking shafts
or bellcrank levers the gear can be easily adapted for various relative positions of
the valve. The motion imparted to the valve, 8, by my improved gear consists of
a motion derived from the piston-rod slide block, 9, and which is equivalent to the
lap and lead, combined with a motion derived from the swinging or vibratory
motion of the connecting rod, 10.
The lap-and-lead motion is transmitted from the piston-rod slide block, 9, by a
link, 11, jointed to a lever, 12, connected by a joint, 13, at its upper end, which is
forked, to the forked end of the valve rod, 5. The lever, 12, is also connected by
a joint, 14, to one end of a rod or link, 15, which has its. other end forked and
jointed to a slide block, 16, fitted to a slotted link, 17, having its radius. of curvature
equal to the link, 15. The slotted link, 17, is fixed by its ends to a carrying

page_text: plate, 18, which is formed or fixed on a rocking shaft, 19, carried in bearings on
the framing (these last mentioned parts being supposed to be removed in figure, 2).
The link block, 16, is movable along the slotted link, 17, for reversing or altering
the cut-off by a link, 20, connecting it to a bellerank lever, 21, which is connected
by a rod, 22, to the reversing hand lever. The slotted link, 17, is made to rock on
the axis of the shaft, 19, by means of a short arm, 23, projecting from its middle
and jointed to an arm, 24, formed on a slotted link piece, 25, which has also
formed on it an arm, 26, which is jointed to a radius rod, 27, having its other end
jointed to a fixed point of the framing. The link piece, 25, is thus linked or
connected to two centres, that of the radius rod, 27, and that of the rocking
shaft, 19, and is capable of a nearly parallel movement in its plane. A slide
block, 28, is fitted to move in the slot of the link piece, 25, and is jointed on a
pin which is fixed in the connecting rod, 10, at a distance from the joint between
that rod and the slide block, 9, such as to give a proper amplitude of movement
with the swinging motion of the connecting rod. The longitudinal movement of
the connecting rod, 10, does not affect the link piece, 25, the slide block, 28, simply
moving along the slot; but the swinging motion of the connecting rod imparts
to the link piece, 25, an up-and-down motion such as would be given by a crank
or eccentric, and this motion makes the curved link, 17, rock on its carrying
shaft, 19.
When the link, 15, is in its middle position relatively to the curved link, 17, as
shown the centre of the link block, 16, is coincident with the axis of the shaft, 19,
and the rocking of the curved link, 17, does not impart any movement to the
rod, 15. The joint, 14, at the other end of the rod, 15, then acts as a fixed fulcrum
to the lever, 12, and this lever with the motion it gets from the piston-rod slide
block, 9, moves the valve rod, 5, to the extent of the lap and lead only. But when
the link block, 16, is by means of the reversing lever moved towards either end of
the curved link, 17, then the rocking motion of that link imparts a reciprocating
motion through the rod, 15, which motion combining with the lap-and-lead motion
gives to the valve spindle, 5, the proper motion for turning the engine in one
direction or the other according to the position given to the reversing lever.
Instead of applying the combined motions to one valve as hereinbefore described,
the motion derived from the piston-rod slide block (9) may be applied to a main
valve and the motion derived from the swinging motion of the connecting rod (10)
may be applied to a separate cut-off or expansion valve.
In the modification shown in figures, 3, and 4, the combined motion (for working
a single valve, 8,) is communicated through the rocking curved link, 17; and is
derived from the slide block, 28, upon the connecting rod, 10. This slide block, 28,
is fitted to work in a slot in a piece, 29, which is jointed by a pin, 30, at its middle
to a link, 31, corresponding to the two arms, 24, 26, of the link piece, 25, of the
modification shown in figures, 1, and 2, and connected in the same way as those
The slotted piece, 29, is formed with an arm, 32, which is connected by a
rod, 33, to an adjusting lever; and it has to be inclined in one direction or the
other to suit the direction of rotation of the engine, and to a greater or less extent
corresponding to the less or greater distance of the slide block, 16, from the middle
of the curved link, 17.
arms.
When arranging the gear shown in figures, 3, and 4, for an engine requiring to
turn in one direction only, the lever or link, 31, may be fixed adjustably or per-
manently to the slotted piece, 29, and a simple bellcrank lever may be substituted
for the curved link, 17.
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 of parts forming one modification of my improved valve
gear substantially as hereinbefore described with reference to figures, 1, and 2, of
the accompanying drawings

page_text: 2-The combination of parts forming a second modification of my improved
valve gear substantially as hereinbefore described with reference to figures, 3,
and 4, of the accompanying drawings.
3-The application of the slotted piece, 25, or 29, for obtaining a transverse
movement for working the valve from the combined longitudinal and swinging or
vibratory movement of the connecting rod, substantially as herein before described.
100
EDMUND HUNT,
Applicant's Agent.