IMPROVEMENTS IN MULTIPLE CYLINDER ENGINES
Year: 1883

page_text: > 16
PROVISIONAL SPECIFICATION left by the said Peter Brotherhood at the
Office of the Commissioners of Patents on the 18th May 1883.
PETER BROTHERHOOD of Belvedere Road Lambeth in the County of Surrey
"IMPROVEMENTS IN MULTIPLE CYLINDER ENGINES"
My invention relates to multiple cylinder engines of the kind in which two or
more cylinders radiate from a central cavity in which a single crank revolves,
connecting rods from the pistons of the cylinders being linked directly to the
crank. I provide at the side of each cylinder a cylindrical slide jacket fitted with
a double piston slide worked from an eccentric within the central cavity by.a
connecting rod directly linked to the slide, and I prefer to make the area of the
inner piston part of the slide somewhat larger than that of the outer piston port,
so that the pressure of the steam or working fluid between the two piston parts
may keep the eccentric link always pressed against the eccentric sheave. In
linking the connecting rod to the piston of each cylinder I adopt the following
arrangement. I fit a boss formed at the end of the connecting rod in a bearing
provided on the face of the piston, and I make this boss tubular and cut through
one side of it a slot. I also cut through the piston a slot of corresponding size,
and I make the slot in the connecting rod boss in such a position in the boss that
as the piston is making its return stroke the two slots come into coincidence, so
that there is free passage for exhaust from the cylinder through the slots in the
piston and the connecting rod boss into the central cavity of the engine. This
passage for exhaust is provided in addition to the passage given by the movement
of the slide, and it has the effect of maintaining free exhaust even when the
exhaust by the slide is throttled or altogether stopped, thus avoiding back pressure
in the cylinder. The eccentric for working the slides may be fixed directly on the
shaft; I prefer however to fit it so as to revolve freely on the exterior of a boss
projecting inwardly from one side of the central cavity, within which boss is
formed a bearing for the main shaft or for a secondary shaft having on it a disc
driven by the crank pin of the main shaft, a crank pin on this disc driving the
eccentric sheave,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Peter Brotherhood in the Great Seal Patent Office on the
6th November 1883.
PETER BROTHERHOOD of Belvidere Road Lambeth in the County of Surrey
"IMPROVEMENTS IN MULTIPLE CYLINDER ENGINES"
My invention relates to multiple cylinder engines of the kind having two or
more single acting cylinders radiating from a central cavity in which revolves a
single crank linked directly by connecting rods to the several pistons. Usually,
engines of the kind referred to are made with three cylinders. I will therefore
describe a three cylinder engine embodying my present improvements, referring to
the accompanying drawings. Fig. 1 is a central vertical longitudinal section.
Fig. 2 is a vertical transverse section on the line XX of fig. 1. Fig. 3 is a similar
section on the line Y Y of fig. 1. Fig. is a side elevation Fig. 5 is a part
section on the line Z Z of fig. 4, and fig. 6 is a plan of one of the cylinders and its
slide casé.
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A is the central cavity into which the cylinders successively discharge the
exhaust, which passes away by the exhaust pipe a on one side. B is the engine
shaft working in a long bearing, preferably lined with soft metal, and having the
balanced crank-pin C: On this crank pin bear the segmental ends of the three
connecting rods D, which are held to it by two rings d. Each connecting rod D
is linked to the deep piston E working in the cylinder F. So far, the construction
and arrangement are of the usual kind. I now proceed to describe the modifica-
tions which I adopt in carrying out my improvements. Each cylinder F has by
its side a cylindrical slide case G, communicating with the cylinder by a short
port g, and opening into the central cavity A. The middle part of the slide case
receives supply of steam or other working fluid by a branch h from a cavity H
to which the working fluid is admitted through a regulating valve h¹, controlled
by the governor. The slide case G is bored somewhat larger in its inner than in
its outer part, and it is fitted with a cylindrical tubular slide K. which is worked by
a connecting rod k having a segmental end bearing against an eccentric L. This
eccentric is free to rotate on a stationary boss l projecting inwardly from the side of
the engine casing, and having its interior lined with soft metal, so as to form a
bearing for a secondary shaft b in line with the main shaft B. On the shaft b
is a disc receiving in a slot a bush fitted on' the end of the crank pin C, and a
pin e', projecting from the back of the disc, enters a hole in the eccentric L. Thus
the eccentric is caused to revolve in unison with the crank C, while there is freedom
to allow for error of allignment of the shafts B and b. The eccentric L is balanced
by a block 2, and it has a groove 13 receiving the edges of the segmental ends of
the slide rods k. The eccentric L, being properly set relatively to the crank C, the
slides K alternate the admission and emission of the working fluid for the cylinders
in succession, the exhaust in each case passing through the slide into the central
cavity A. As the inner part of each slide is of greater area than its outer part,
the segmental ends of the slide rodsk are always kept pressed against the eccentric,
so that there is no blow resulting from alternation of their movement, even when
the speed is very great. As engines of this kind are especially adapted for being
worked expansively with steam, compressed air or other fluid at very high pressure,

page_text: and the eccentric is therefore set so as to cut off supply at a very early period of
the piston-stroke, it is necessary to provide for relief of the pressure that would
act against the backstroke of the piston when the slide closes the cylinder port
during exhaust. For this purpose, I cut through the piston a rectangular slot e,
and I cut a corresponding slot into the eye d of the connecting rod D, which eye
is made tubular. The latter slot is cut in such a position that, as the piston E is
making its backstroke at the time when the slide K is about closing the exhaust,
it comes into coincidence with the slot e of the piston, and thus there is afforded
free passage for exhaust from behind the piston through the slot e and the slot and
eye d into the cavity A, and the back pressure in the cylinder is thus completely
relieved; notwithstanding that the port g may be closed by the slide.
For governing the engine, I mount on a sleeve fitted on the secondary shaft B
weights M in the form of bent levers, the inner arms of which bear against a
spindle m which is free to slide in a hole bored centrally along the shaft b. This
spindle bears against a lever N which is controlled by an adjustable spring n, and
which engages the stem of the balanced regulating valve h¹.
Although I have described my improvements more particularly as applied to a
three cylinder engine, it is obvious that the arrangement of slide and eccentric and
the slots in the piston and eye of the connecting rod are equally applicable when
there are less or more than three cylinders, and whether the engine be worked by
stean, compressed air, or other elastic fluid.
The construction and arrangement of some parts of the engine may be modified,
as shewn in fig. 7, a longitudinal section, in figs. 8 and 9, which are transverse
sections on X X and Y Y respectively, fig. 10 being a side elevation of the engine
and fig. 11 a plan of one of the cylinders and its slide case. The parts in these
figures corresponding with those in figs 1 to 6 inclusive are marked with similar
letter, and I need not further describe them, except as to such modifications as I
will now state. The crank shaft B B' is made to extend on both sides of the
crank pin C, so as to work in bearings in both sides of the casing, and counter-
balances C¹ C¹ are secured by setting screws on parts of the shaft turned circular
on each side of the crank pin. The segment ends of the connecting rods D, instead
of bearing directly on the crank journal, bear upon a bush C³ embracing the
journal, and are held up to it by rings & divided in halves bolted together. The
outer ends of the slide cases G are made of smaller bore than the inner ends by
introducing removeable linings G¹ forming extensions of the covers, so that, by
removing the covers, room is left for passage of the larger inner ends of the slides,
should it be necessary to take them out. The eccentric L is made in two circularly
grooved sheaves bolted together, and embracing between them the segmental T ends
of the slide rods k. These sheaves are fitted to revolve on & trunnion formed on
the bearing of the crank shaft, and are driven by a pin which projects into a
hole in the crank. The regulating valve h', instead of being worked by a lever as
previously described, is worked directly by the governor M M, being situated in
line with it within the cavity H which receives a regulated supply of steam or
other working fluid from an exterior cavity H¹, communicating with the supply
pipe h. The governor weights M M are mounted on the cylindrical casing of the
valve h¹ which is caused to revolve by a coupling to the shaft B'.
.
Having thus described the nature of my invention, and in what manner the
same is to be performed, I claim as improvements in multiple cylinder engines of
the kind herein before referred to--
First The construction of the piston slide K with the area of its inner end
greater than the area of its outer end, so that its connecting rod k is always subject
to thrust, substantially as, and for the purposes herein set forth.
Second The construction and arrangement of the eccentric L and its driver,
so as to allow for error of allignment with the main shaft, substantially as herein
described, with reference to figs 1 and 3.

page_text: Third The construction of the joint of the connecting rod to the piston with a
tubular and slotted eye, to operate in combination with a slot through the piston,
substantially as and for the purposes herein set forth.
In Witness whereof I the said Peter Brotherhood have hereunto set my hand
and seal, this First day of November in the year of Our Lord one thousand, eight
hundred and eighty-three.
PETER BROTHERHOOD. (L.S.)