Improvements in Valve Gear for Marine and other Engines.
Year: 1890

page_text: Date of Application, 26th Sept., 1890
Complete Specification Left, 25th June, 1891-Accepted, 25th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear for Marine and other Engines.
I, JAMES HOWDEN, of 8 Scotland Street, Glasgow, in the County of Lanark,
North Britain, Engineer, do hereby declare the nature of this invention to be as
follows, that is to say :-
My said invention has for its object to improve and simplify the construction or
arrangement or combination of the parts of valve gear for marine and other
engines.
In carrying out my invention according to one modification in the case of engines
with two or more cylinders, I employ a counter shaft suitably placed for acting in
the most direct way conveniently possible on the several valve spindles and driven
in any convenient manner from the crank shaft. A single eccentric is provided for
acting on each valve spindle, and is fitted so as to be capable of sliding across upon
parallel surfaces on opposite sides of the shaft, for varying the cut-off and for
reversing. Each eccentric is made in halves and has fixed to it two steel bars
which when the eccentric is closed on the shaft enter through diametrically
opposite slots into the interior of the shaft, which is hollow. In the interior of the
shaft there is an inclined steel bar which fits and works between the suitably shaped
inner ends of the bars of the eccentric. The inclined bar rotates with the shaft
but can be moved longitudinally in it, and when so moved shifts the eccentric
across in one direction or the other accordingly. The counter shaft is by preference
made with sections for each valve, suitably coupled together and capable of easy
separation for examination or repair. The inclined bars are all connected together
by intermediate rods or shafts and couplings, also admitting of casy separation; and
the longitudinal movement for adjusting the eccentrics, is imparted at one end by
means of a sliding bar connected by a swivel coupling. The sliding bar may be
moved by hand gear or by means of steam or hydraulic motor apparatus controlled
by hand levers.
In other modifications instead of every eccentric of a set being arranged to act
directly on its valve spindle, all or some of them may be arranged to act through
rocking shafts, in which case the several eccentrics may be placed near or close
together or there may be a single eccentric with separate rings or straps on it for
the several valve spindles, the movements being transmitted from the eccentric in
suitable different directions. The set of nearly placed eccentrics or the single
eccentric may be on a comparatively short counter shaft, or on one end of the crank
shaft.
Instead of the eccentrics being moved across by means of longitudinally moving
inclined bars acting on bars fixed to the eccentrics as hereinbefore described, they
may be moved by means of transverse screw spindles working in internally screwed
bosses of pinions, either spur or bevil, arranged in the hollow shaft and acted on by
a longitudinally or helically moving rack, or by an arrangement of bevil pinions or
of bevil and spur pinions.
In many cases it will be convenient to drive the counter shaft by means of a
device which I believe to be novel, and which comprises a single crank or eccentric
on the crank shaft, a single crank or eccentric on the counter shaft, and a single
crank or eccentric on a stud or short shaft. The stud or shaft of the third crank
or eccentric is placed in any convenient position such that it and the other two are
at the angles of a triangle. A triangular frame connects the three cranks or

page_text: eccentrics with bearings on each, or separate connecting rods may, connect each one
with the other two.
Dated this Tments fifth day of Santambon 1800
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Valve Gear for Marine and other Engines.
I, JAMES HOWDEN, of 8, Scotland Street, Glasgow, in the County of Lanark,
North Britain, 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 has for its object to improve and simplify the construction or
arrangement or combination of the parts of valve gear for marine and other
engines.
I hereunto append three sheets of explanatory drawings to be hereinafter referred
to in describing my improvements.
One modification is shown on Sheets, 1, and 2, of the drawings Figures, 1,
and 2, being side and end elevations, and Figures, 3, to 7, enlarged sectional views of
details.
Figures, 8, and 9, Sheets 3, are side and end elevations of another modification
Figure, 10, being an enlarged sectional view of a detail.
In these drawings the same reference letters and numerals are used to mark the
same or like parts wherever they are repeated.
In carrying out my invention according to one modification in the case of engines
with two or more cylinders, and as shown by way of example, on Sheets, 1, and 2,
of the drawings, on which triple-expansion engines are delineated, I employ a
counter shaft, A, suitably placed for acting in the most direct way conveniently
possible on the several valve spindles, B1, B2, B3, and driven in any convenient
manner from the crank shaft, C. A single eccentric, E 1, E2, E 3, is provided for
acting on each valve spindle, and is fitted so as to be capable of sliding across (as
will be best understood from the enlarged views, Figures, 5 and 6,) upon parallel
surfaces, 21, on opposite sides of the shaft, A, for varying the cut-off, and for
reversing. Each eccentric, E, is made in halves and has fixed to it two steel
bars, F, which when the eccentric is closed on the shaft, A, enter through
diametrically opposite slots, into the interior of the shaft, which is hollow. In the
interior of the shaft, A, there is, for each eccentric, an inclined steel bar, G, which
fits and. works between the suitably shaped inner ends of the bars, F, of the
eccentric. The inclined bar, G, rotates with the shaft, A, but can be moved longi-
tudinally in.it, and when so moved shifts the eccentric across in one direction or the
other accordingly. The counter shaft, A, is by preference made with sections for
each valve, as shown in Figures, 3, and 4, which, together, correspond to the
complete shaft shown in Figure, 1.
[It may here.be explained that as is common in engineering drawings the various
parts of the valve gearing are shown in their middle positions, and not in their
proper positions,.relatively to each other which are however well understood.]
The several sections of the counter shaft, A, and those of the internal parts, are.
suitably coupled together in a manner admitting of easy separation of any one
section for. examination or repair. The inclined bars, G, are all connected by
intermediate rods or shafts, 22, and couplings; and the longitudinal movement for
adjusting the eccentrics, is imparted at one end by a slide, H, connected to it by a
swivel.coupling, and working in a fixed guide, 23. The slide, H, has fixed. to it a
rod,, H. 1,. connected to a starting and reversing engine, H2, and having. at
one part a. toothed rack in gear with a pinion on a shaft, having on it a hand-
wheel, H 3.

page_text: Whilst the counter shaft, A, may be driven in any convenient way from the
crank shaft, C, it will in many cases be convenient to drive it by means of a
device shown in Figures, 1, and 2, and which I believe to be novel. This device
comprises a single crank, J 1 (or it might be an eccentric) on the main shaft, C,
a second single crank, J2 (or eccentric) on the counter shaft, A, and a third
single crank, J3 (or eccentric) on a stud or short shaft, K. The stud or short
shaft, K, of the third crank, J3, is placed in any convenient position such that
it and the other two are at the angles of a triangle of suitable form. By way
of example two positions are shown in Figure, 2, one in full lines and the other
in dotted lines. A triangular frame, L, connects the three cranks, J 1, J 2, J 3,
or separate connecting rods may connect each one with the other two.
In other modifications of my improved valve gear, instead of every eccentric
of a set being arranged to act directly on its valve spindle, all or some of them
may be arranged to act through rocking shafts, in which case the several
eccentrics may be placed near or close together; or there may be a single
eccentric with separate rings or straps on it for the several valve spindles, the
movements being transmitted from the eccentric in suitable different directions.
The set of nearly placed eccentrics or the single eccentric may be on a com-
paratively short counter shaft or on one end of the main or crank shaft, C.
The last mentioned arrangement is adopted in the example shown on Sheet, 3, of
the drawings, the single eccentric, E, fitted with three straps or rings with their
rods, M1, M2, M3, being fitted upon the forward end of the main shaft, C,
prolonged and made tubular for the purpose. In this example, the high-pressure
valve casing, N 1, is placed at the forward end of the engines, and the eccentric
rod M 1, for it passes up directly from the eccentric, E, to the valve rod. The
second eccentric rod, M2, is connected to a lever on a rocking shaft, P, and
another lever on this shaft is connected by a rod, P 1, to the valve rod of the inter-
mediate valve casing, N 2. The third eccentric rod, M 3, is connected to a lever
on a rocking shaft, Q, another lever on which is connected by a rod, Q1, to a lever
on a rocking shaft, Q2, having on it a lever connected by a rod, Q 3, to the valve
rod of the low-pressure valve casing, N 3. If it is desired to have the high-
pressure valve casing, N 1, at the side instead of at the end, the eccentric rod, M 1,
may still be in the position in which it is shown in Figure, 9, its action
being transmitted to the valve rod by a lever such as is indicated by dotted
lines, Q4.
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 the modification of my improved valve gear,
substantially as shown on Sheets, 1, and 2, of the accompanying drawings and
hereinbefore described.
2-The combination of parts forming the modification of my improved valve gear,
substantially as shown on Sheet, 3, of the accompanying drawings and hereinbefore
described.
3-The eccentric shifting device consisting of a longitudinally movable inclined
bar fitted within the shaft carrying the eccentric, and acting on bars fixed to the
eccentric and extending through slots into the shaft substantially as hereinbefore
described.
4-The device for driving the counter shaft. for working the valves and consisting
of a triangular frame or equivalent set of connecting rods having its angles jointed
on cranks or eccentrics, severally, on the main shaft, on the counter shaft, and on a
third shaft or stud, substantially as hereinbefore described.
Dated this Twenty-third day of June 1891.
EDMUND HUNT,
Applicant's Agent.