Year: 1887

page_text: Date of Application, 16th Mar., 1887.
Specification Accepted, 19th Apr., 1887.
1, PETER BROTHERHOOD of Belvedere Road, Lambeth in the County of Surrey,
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 :-
My invention relates to engines of that kind in which three single acting cylinders
are arranged, with their axes radial, around a central cavity, and their pistons act on
a single crank revolving within the cavity, each piston being propelled in turn by
steam or other fluid under pressure admitted into the cylinder beyond it, and being
in turn caused by the crank to make its back stroke expelling the exhaust.
I will describe my present improvements referring to the accompanying drawings.
Fig. 1 is a vertical section through the axis of the engine shaft and of the upper
cylinder.
Fig. 2 is a part section shewing one cylinder arranged in a modified manner as to
exhaust.
Fig. 3 is a section on X X of Fig. 1.
Fig. 4 is a part section on Y Y of Fig. 1.
The engine shaft. S has a crank pin which has a squared end projecting into a
cam disc D. This disc revolves on a fixed trunnion T projecting inwardly from the
casing. The piston P of each of the three cylinders A¹ A A³ has jointed to it a
hollow connecting rod R preferably of rectangular section having a widened segmental
base which bears on the crank pin C, the three bases being held on by rings on each
side. By making the connecting rods R hollow, as shewn, great stiffness combined
with lightness is obtained, the hollow also forming a passage for part of the exhaust,
when the rod R is in such an attitude that a slot E at the top of the rod coincides or
partly coincides with a slot through the piston.
The steam or working fluid is supplied to an annular cavity B which is in com-
munication with the three cylindrical slide cases G¹, G, G³. In each of these cases
there is fitted a piston slide valve H having a tubular stem containing a helical spring
which presses the extremity of the stem against the periphery of the cam disc D.
As this disc revolves with the crank the slides H are successively pressed down by

page_text: these springs so as to admit the steam or working fluid to the cylinders in rotation,
and pressed up by the cam D so as to close the admission ports.
Each cylinder may have as shewn in Fig. 1 another slide K for exhaust worked by
a cam L on the shaft S the exhaust passing by an annular cavity B' to an exhaust
pipe. Or, as shewn in Fig. 2, the exhaust slide and cavity B¹ may be dispensed with
by providing the cylinder with lateral apertures M communicating with the central
cavity of the engine so that when the piston P as it approaches the end of its instroke
uncovers these apertures a large portion of the exhaust fluid escapes into the central
cavity, the residue afterwards, as the piston returns, escaping by the slot E through
the hollow of the connecting rod R and out at lateral holes provided at the sides of
the connecting rod.
For the purpose of lubricating the bearing of the cam disc D and those of the
connecting rods, I supply oil at O to a hollow in the trunnion T, whence it flows by
a passage to lubricate the bearing surface of D and also to supply the hollow interior
of the crank C from which oil holes c lead the lubricant to the hearing surfaces of the
connecting rods.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed, I declare that what I claim is :-
1. In a three cylinder engine, the construction and use of tubular connecting rods
each at its one end jointed to the piston and provided with an escape slot, and at its
other end expanding to form a segmental base which bears against the crank,
substantially as and for the purposes herein set forth.
2. In a three cylinder engine, the construction and use of piston slide valves having
tubular stems enclosing helical springs in combination with cam discs against which
the valve stems are pressed.
3. In a three cylinder engine the combination of a hollow trunnion T the cam
disc D and the hollow crank C with their respective oil passages O, and c for
lubrication, substantially as described.
Datad this 16th day of March 1007
ABEL & IMRAY,
Agents for the Applicant.