AN IMPROVEMENT IN .. DIRECT ACTING STEAM PUMPS AND OTHER STEAM OR FLUID PRESSURE ENGINES
Year: 1884

page_text: CONFLIC
DEEULLICATIOA.
I, JOSEPH BERNAYS of N° 96 Newgate Street in the City of London, Engineer,
do hereby declare the nature of my said invention for "AN IMPROVEMENT IN
..
DIRECT ACTING STEAM PUMPS AND OTHER STEAM OR FLUID PRESSURE ENGINES
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 a construction and arrangement of the connecting rod
and crank of a direct acting steam pump or other steam or fluid pressure engine,
applicable particularly in cases where the principal part of the power is delivered
directly on the work that has to be performed, without passing through the crank
or flywheel shaft, as in a direct acting steam pump. I make the connecting rod of
the same length as the crank throw and provide means of ensuring its turning
quite round the crank pin during every revolution of the latter, and of determining
the movements of the connected paris. I am thus enabled to shorten the crank to
half the length that it would otherwise have to be for a given stroke of piston, and
I thus reduce the size, strength and weight of the shaft and flywheel, and of the
engine generally. The accompanying drawings illustrate the construction and
arrangement which I adopt for this purpose.
Figs 1 to 8 inclusive are diagrams shewing the positions of the end of the piston
rod P, the crank C, and the connecting rod R at different parts of a revolution.
From these it will be seen that the stroke of P is four times the radius of the
crank C,. or double the stroke that would be due to that crank radius if the
connecting rod R were, as usual, of greater length than the crank. It will also be
observed that, if the connecting rod R be extended beyond the crank pin to double
the length, the extremity of the extended part travels to and fro' in a straight
line crossing at right angles the line of stroke of the piston rod P.
Fig. 9 is a front view and fig. 10 a side view, partly in section, of a direct acting
steam pump to which the arrangement illustrated by the diagrams is applied.
S being the steam cylinder and W the pump, the rigid connection of their
piston-rods or plungers & wis bracketted out at B to give room for the central
connecting rod R, which is journalled on the pin P of the plunger rods and on the
pin of the crank C. The connecting rod is extended beyond the crank pin and
terminates with a circularly rounded end r, the centre of r being at the same
distance as the centre of P from the contro of the crank pin. As seen in the

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diagrams Figs. 3 and 7 the crank is, as it were, on a dead centro in these positions.
In order to ensure its movement in the proper direction, I cause the end
engage at each extreme of its transverse stroke in a rounded notch or recess N N
formed in the framing of the engine, this engagement determining the proper
movements of the parts, when they are at or about their middle position.
Obviously the extremity r might have a projecting pin fitted to work in a
transverse guido or groove extending from N to N so as to be guided during its.
whole stroke, but as the guiding of r throughout its whole stroke is unnecessary,
I prefer the arrangement shewn in fig. 9. It is not necessary that the extension
to be of exactly the length of the crank; it may be shorter, so that r travels in a
curve, for which the recesses N may be made suitable.
In cases where it may be desired to make the piston or plunger rods 8. w
continuous without any bracketted out part such as B, the construction shewn in
fig. 11 may be adopted, the crank C and connecting rod R being arranged at one
side of the rod and a suitable guide G being provided on the other side, to resist
any tendency of the rods 8 w to turn. A modified arrangement is shewn in section
at fig. 12 and in front view at fig. 13. In this case the connecting rod R is made
in the form of a disc, or it might be a ring or segment of a ring, sunk in a recess of
the crank disc C, this recess having an eccentricity equivalent to the crank throw.
Although I have shewn the arrangement of crank and connecting rod, according
to my invention, as applied to a direct acting steam pump, in which the chief part
of the power is transmitted directly from 8 to w, only such portion of it being
communicated through the crank to the flywheel as may be necessary for giving
regularity of movement and working the steam slide or valves, it is obvious that a
similar construction may be adopted in other steam or fluid pressure engines in
which there are similar conditions as to transmission of the power, or in which the
piston rod is adequately guided, evon where a considerable part of the power passes
through the crank.
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, In a direct acting steam pump or other steam or fluid pressure engine, the
use of a connecting rod of length equal to the crank radius, substantially as and for
the purposes herein set forth.
2, In an engine having its crank and connecting rod arranged in the manner
referred to in the preceding claim, extending the connecting rod beyond the crank
pin and providing notches or recesses in which the extended part engages at the
extremes of its transverse stroke, substantially as herein described.
VHIS
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.