Improvements in Valve Gear for Steam and other Fluid Pressure Engines, Steam Pumping Engines, and the like.
Year: 1895

page_text: Date of Application, 5th Jan., 1895
Complete Specification Left, 5th Oct., .1895-Accepted, 16th Nov. 1895
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear for Steam and other Fluid Pressure
Engines, Steam Pumping Engines, and the like.
JAMES CADOUX HUDSON 75 Upper Ground Street Blackfriars Road London
Engineer do hereby declare the nature of this invention to be as follows:-
In a steam engine of ordinary construction when the motion of the piston of
steam cylinder is transmitted by a connecting rod and crank to the crankshaft,
and the slide valve of the steam cylinder is worked by an eccentric on crankshaft,
it is found that with an equal lead at each end of the slide valve the steam
admission is not of equal duration to each end of the steam cylinder, consequently
the power developed by the in stroke of the piston varies from that of the out
stroke; this inequality being due to the angular position of the connecting rod in
the course of a revolution; since for instance when the piston is in mid stroke, the
crank will not have made a half revolution. This irregularity is greater in an
engine with a short connecting rod than in one with a long connecting rod. My
improved valve gear is so arranged that the inward and outward stroke of the
piston shall have an equal admission of steam, equal lead, pre-exhaust, and
compression; or by a variation in the disposition of parts I can give an increase
of admission at either the in or the out stroke.
I use an ordinary eccentric on the crankshaft for actuating the valve motion and
having eccentric straps of ordinary construction, the eccentric rod is comparatively
short, or the pin of eccentric.rod may be in a joint formed on eccentric straps.
I couple this pin to one end of a vibrating link-the other end of link is attached
to a fixed pin or fulcrum-I couple the eccentric rod by links to the valve rod→
the links may fit on the same pin by which the vibrating links are coupled.
The fixed pin or fulcrum of vibrating link is placed in such a position that the
are made by the free end of the link and the eccentric pin, cuts the line through
the centre of slide valve spindle and crankshaft, or a line radiating from centre of
crankshaft at an angle and at about the centre of stroke of eccentric pin; by
arranging the fixed centre from which the link vibrates so that the angle at which
the free end of the link and the eccentric pin cuts, the centre line of valve
spindle may be more or less acute, I can either obtain an equal cut off to each
end of steam cylinder or make the admission at either end more than the other.
Thus introducing an irregularity of motion into the valve gear which will
counteract the irregularity of movement of the inward and outward motion of
the piston caused by the connecting rod. This gear with the necessary alteration
is applicable to an engine with a return connecting rod, or if found desirable the
slide valve can be worked by a rocking shaft in which case the vibrating link will
be represented by one arm of a lever on the rocking shaft the free end of the
lever connected to the eccentric and having a motion at an angle to a radial line
from centre of crankshaft. Another lever on rocking shaft will be connected to
the slide valve rod and actuate it. Various modifications may be used to suit
different forms of engines.
Dated this 5th day of January 1895.

page_text: Improvements in Valve Gear for Steam and other Fluid Pressure
Engines, Steam Pumping Engines, and the like.
JAMES CADOUX HUDSON 75 Upper Ground Street Blackfriars Road London
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 :-
In a steam engine of ordinary construction when the motion of the piston of
steam cylinder is transmitted by a connecting rod and crank to the crankshaft-
and the slide valve of the steam cylinder is worked by an eccentric on crank-
shaft it is found that with an equal lead at each end of the slide valve the
steam admission is not of equal duration to each end of the steam cylinder-
consequently the power developed by the in stroke of the piston varies from that
of the out stroke-this inequality being due to the angular position of the
connecting rod in the course of a revolution since for instance when the piston
is in mid stroke, the crank will not have made a revolution.
This irregularity is greater in an engine with a short connecting rod than in one
with a long connecting rod.
My improved valve gear is so arranged that the inward and outward stroke of
the piston shall have an equal admission of steam-equal lead pre-exhaust-and
compression; or by a variation in the disposition of parts I can give an increase
of admission at either the in or the out stroke.
I use an ordinary eccentric on the crankshaft for actuating the valve motion
and having eccentric straps of ordinary construction the eccentric rod is. com-
paratively short, or the pin of eccentric rod may be in a joint formed on eccentric
straps. I couple this pin to one end of a vibrating link the other end of link is
attached to a fixed pin or fulcrum. 1 couple the eccentric rod by links to the
valve rod the links may fit on the same pin by which the vibrating links are
coupled. The fixed pin or fulcrum of vibrating link is placed in such a position
that the arc made by the free end of the link and the eccentric pin, cuts the line
through the centre of slide valve spindle and crankshaft, or a line radiating from
centre of crankshaft at an angle and at about the centre of stroke of eccentric
pin by arranging the fixed centre from which the link vibrates so that the angle
at which the free end of the link and the eccentric pin cuts the centre line of
valve spindle may be more or less acute. I can either obtain an equal cut off to
each end of steam cylinder or make the admission at either end more than the
other. Thus introducing an irregularity of motion into the valve gear which
will counteract the irregularity of movement of the inward and outward motion
of the piston caused by the connecting rod. This gear with the necessary
alteration is applicable to an engine with a return connecting rod, or if found
desirable the slide valve can be worked by a rocking shaft, in which case the
vibrating link will be represented by one arm of a lever on the rocking shaft the
free end of the lever connected to the eccentric and having a motion at an angle
to a radial line from centre of crankshaft.
Another lever on rocking shaft will be connected to the slide valve rod and
actuate it. Various modifications may be used to suit different forms of engines.
In order that my said invention may be most fully understood and readily
carried into effect, I will proceed to describe the drawings hereunto annexed.

page_text: :
DESCRIPTION OF DRAWINGS.
My invention is represented. by the accompanying drawings-the same letters
and references indicate the same parts in all the figures. Fig. 1. is a part elevation
of a steam fire engine or pumping engine to which my improved valve gear is
applied. Fig. 2 is a front elevation of the same, (A) is the steam cylinder end
and (B) the pump end of the engine, (C) is the frame, (D) the crankshaft with
cylinder piston rods (E) passing on either side of it and connected to the
crosshead and pump piston rod (F). (G) is the crank and (H) the connecting
rod. (I) is an eccentric having eccentric straps (J) of ordinary construction, and
to a point on the eccentric straps (J) I couple one end of the vibrating link (K)
by means of the pin (L). The other end of vibrating link (K) is attached to a
fixed point or fulcrum (N). The links (0) connect the eccentric straps (J; to the
slide valve rod (P) by a pin (Q); the links (0) may be coupled to the eccentric
straps (J.) by the pin (L.) or by a separate pin and joint (L) as shewn at Fig. 11.
The fixed pin or fulcrum (N) is placed in such a position that the arc made by
the free end of the link and eccentric pin cuts the centre line of slide valve spindle
and connecting rod or a line radiating from centre of crankshaft at an angle and
about the centre of stroke of eccentric pin. The eccentric pin (L.) and free eud
of lever (K) thus moves from one side to the other side of the centre line of valve
rod and crankshaft, the result being to retard the movement of the slide valve rod
at one part of its stroke and to accelerate the movement of the valve rod during
the remaining part of its stroke. Thus an irregular motion is given to the valve
rod which counteracts the irregularity otherwise caused by the angular motion of
the connecting rod. The irregular motion given to the valve rod by the valve
gear and consequently the distribution of the steam in the cylinder depends upon
the position of the fixed pin or fulcrum (N) and the angle at which the free end
of link (K) and eccentric pin (L) cuts the centre line of slide valve spindle or a
line radiating from centre of crankshaft. Fig. o shews the fixed pin (N) in such
a position and the free end and eccentric pin (L) cutting the centre line at such an
angle as to give an equal distribution of steam on the in and out stroke of piston
and consequently a more even power is exerted. Fig. 6 shews the fixed pin or
fulcrum (N) moved to a position (N¹) and the free end of link and eccentric
pin (L) cutting centre line at a greater angle than shewn at Fig. 5. The effect of
this being to give an increased steam admission on the down or out stroke of the
engine with a return connecting rod or an increased steam admission on the up or
in stroke of an engine having a connecting rod forward.
Fig. 7 shews the fixed pin or fulcrum (N) moved to a position (N2) the free end
of link and eccentric pin (L) cutting the centre line at a less angle than shewn at
Fig. 5 or Fig. 6. The effect being to give an increased steam admission on the
up or in stroke of the engine with a return connecting rod and an increased
steam admission on the down or out stroke of aL engine with connecting rod
forward.
Figs. 3 & 4 shew another arrangement of my improved valve gear in which a
rocking shaft (R) is substituted for the fixed pin or fulcrum (N) in Figs. 1 and 2.
The vibrating link (K) being represented by one arm of a lever (S) the free end
being coupled by a pin (L) to the eccentric straps (J) another lever (U.) is
attached to rocking shaft (R.) the free end being coupled by links (V) to pin (Q)
of slide valve rod (P).
Figs. 8. 9 & 10 shews the positions (R¹) and (R2) in which the rocking shaft (R.)
may be placed to give an equal distribution of steam or an increased admission
on the in or out stroke of the piston.
In Figs. 1. 2. 3 & 4 the valve gear is shewn as applied to a steam fire or
pumping engine, having crankshaft crank and return connecting rod, but I would
have it understood that my valve gear is equally suitable and may with certain
modifications be applied to any ordinary engine in which the motion of piston of
steam cylinder is transmitted by a connecting rod and crank to the crankshaft of
the engine.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is..
"
:
.
Firstly. In a steam engine having crank and connecting rod the combination of
vibrating link in connection with eccentric straps and gear to work slide valve of
steam cylinder arranged as described for the purposes of equalizing the distribution
of steam to each end of steam cylinder or varying same as may be desired in the
manner shewn by Figs. 1 & 2 Diagrams 5, 6 & 7 on drawings attached.
Secondly. The arrangement of vibrating lever and valve gear as shewn in
Figs. 3 & 4 and Diagrams 8, 9 & 10 of drawings attached and as used for the
purposes as in first claim.
Thirdly. The arrangement of vibrating link as in Fig. 11 of drawings attached,
to eccentric by a pin separate from the pin to which the links to valve rod are
attached for the purposes and in the manner described and illustrated.
Dated this 5th day of October 1895.
JAMES CADOUX HUDSON.