Improvements in and Connected with Valves for Hydraulic Motors.
Year: 1888

page_text: Date of Application, 12th Nov., 1888
Complete Specification Left, 12th Aug., 1889-Accepted, 14th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in and Connected with Valves for Hydraulic Motors.
I WILLIAM SNELLING of 13 Willow Vale, Shepherds Bush, in the county of
Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention consists in the construction and operation of valves for hydraulic
motors whereby practically instantaneous opening and closing of the admission and
exhaust ports may be ensured with the object of reducing waste of the motive power
to a minimum. To this end 1 employ a combined admission and exhaust valve
consisting of a hollow cylinder or truncated cone, closed at its outer end but open at
its inner end to the cylinder ports, and having admission and exhaust ports formed in
and suitably disposed on its surface.
For double acting motors I employ one such combined valve for each end of the
cylinder.
The valves receive an intermittent rocking or oscillating motion in seatings in their
casing having ports connected with the supply and exhaust, and each valvo is so set
that when the admission port is open the exhaust port is closed and vice versa.
Pressure is admitted through the hollow valve to the cylinder and the exhaust passes
back at the return stroke through the same valve to the exhaust pipe.
By this arrangement a very short travel is required for the valves and they are
arranged adjustable so as to provide for any desired speed of cut off. The required
motion is imparted to them either by levers and rods operated either by cams suitably
disposed on the fly wheel, or by tappets on a countershaft, or by an eccentric and trip
action or in other suitable manner by which an instantaneous action may be ensured:
The usual adjusting and antifriction arrangements are provided.
Dated this 12th day of November 1888.
J. C. CHAPMAN,
Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in and Connected with Valves for Hydraulic Motors.
I WILLIAM SNELLING of 13 Willow Vale, Shepherds Bush in the county of
Middlesex, 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 :—
This invention relates to certain improvements in the construction and operation of
valves for motors whereby practically instantaneous opening and closing of the
admission and exhaust ports may be ensured with the object of reducing waste of the
motive power to a minimum.
The improved construction of valves is applicable to motors worked by liquid,
vapour or other fluid pressure.
I will now fully describe my invention in reference to the accompanying drawings
in which Figure 1 is an elevation of a double acting motor having my improvements
applied thereto, Figure 2 is a part and elevation thereof: Figure 3 is a plan of
cylinder, valve casing, and operating gear. Figure 4 is a sectional elevation of one
valve, Figures 5 and 6 are sections on line o o Figure 3, showing reversed positions
of valves during the travel of the piston.
In all the figures similar letters indicate similar parts.
I employ a combined admission and exhaust valve V, shown best in Figure 4,
consisting of a hollow tapered plug or truncated cone closed at its outer or larger end
TDC7

page_text: but open at its inner end, and having admission and exhaust ports a and e respectively
cut through and suitably disposed on its surface.
For double acting motors I employ one such valve for each end of the cylinder C
which serves both for admission and exhaust, and I mount the valves in seats of
corresponding internal taper fixed in a solid block B through which suitably shaped
passages are formed leading from the pressure supply A to the admission ports a. a of
the valves, and from the exhaust ports e e thereof to the exhaust pipe E.
The inner open ends of the valves are open to the interior of the cylinder and to
the outer ends oscillating motion is imparted as hereinafter set forth.
By this construction I am enabled to make the admission and exhaust ports very
long and narrow hence the travel of the valve is very short, the narrower the ports
the less oscillation being required and the cut off is thus almost instantaneous while
the loss in clearances is practically nil, and waste of motive power is reduced to a
minimum.
The method of imparting the required oscillating motion to the valves is illustrated
in the figures; To each valve is connected by a flango as illustrated, or by a squared
head, key or otherwise a lever the other end of which is adjustably connected to a
horizontal rod or lever L and thus the valves are rigidly connected and move
synchronously. By the adjustment of these connections the stroke or travel of the
valvos can be regulated to any required speed or degree of cut off. In suitable
position on the lever I are centered two rollers R R which may be of vulcanite or
other suitable material and covered if desired with any yielding material such as
leather rubber or the like.
Between said rollers R R' runs one side of the rim fof the fly or other wheel of
the engine: On opposite sides thereof diametrically opposite to one another are
mounted two striking cams S S₁ of proper configuration and having any device for
adjusting their position such as is illustrated at s. s: the one cam S projects internally
so as to strike the roller R at each revolution and the other S¹ externally so as to
operate in like manner the roller R₁. Thus at each revolution one reciprocation is
given to lever L and thereby through levers ll synchronous motion is imparted to the
two valves V. V. The same motion of the valves may in some cases be obtained by.
tappets, excentrics, or in other suitable manner the usual adjusting and antifriction
arrangements being provided.
The valves are set by the adjustment of the levers 77 in such position that when the
admission port a of either valve is fully open the exhaust e of the same valve is shut
but that of the other is fully open, as illustrated in Figures 5 and 6.
The cams S S¹ are adjusted in such a manner that during the passage of the dead
centres the ports are not quite shut, and the cushion of water or fluid thus intervening
between the piston and the cylinder covers at the ends of the stroke. obviates any
tendency to knock at the end of the stroke even without the use of the usual air
vessel (though I prefer to employ such). Immediately after passing the dead_centres
the admission and exhaust ports are fully opened as illustrated in Figures 5 and 6,
and the full pressure is applied to the piston at the most favourable points of leverage
of the crank.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The construction of valves substantially as described and illustrated.
2. The method of operating valves constructed as set forth and claimed substantially
in the manner described and illustrated.