AN IMPROVEMENT. IN MULTIPLE CYLINDER ENGINES
Year: 1884

page_text: I, PETER BROTHERHOOD of Belvedere Road, Lambeth, in the county of Surrey,
Engineer, do hereby declare the nature of my invention for "AN IMPROVEMENT.
IN MULTIPLE CYLINDER ENGINES" to be as follows:-
My invention relates to engines having three or more cylinders, arranged radially
around a single crank on which all the pistons act successively, as in the well
known kind of engines termed "Brotherhood's three-cylinder engine."
The object
of my invention is to arrange engines of this kind to work as compound engines.
For this purpose, at the outer end of each of the main cylinders of the engine, I fix
in the same axial line a smaller cylinder having its piston rod connected to or
butting against the main piston and having steam pressure constantly tending to
press the piston inwards. I provide also a cylindrical slide worked from an
eccentric on the crank shaft, this slide in each case governing ports whereby steam
is first admitted under the smaller piston, then passed to the larger cylinder above
its piston and finally discharged into the cavity of the casing. Thus the smaller
piston; during its instroke is subjected to pressure inwards, the pressure on both
sides of it being balanced during its outstroke, during which the steam is being
discharged from the larger cylinder.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
. London, W.C.

page_text: I, PETER BROTHERHOOD, of Belvedere Road, Lambeth in the County of Surrey,
Engineer, do hereby declare the nature of my invention for "AN IMPROVEMENT
IN MULTIPLE CYLINDER 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 engines having three or more cylinders arranged radially
around a single crank on which all the pistons act successively, as in the well
known kind of engine termed Brotherhood's three cylinder engine. The object of
my present invention is to arrange engines of this kind to work as compound
engines. For this purpose, at. the outer end of each of the main cylinders of the
engine I fix in the same axial line a smaller cylinder, having its piston rod
connected to or butting against the main piston and having steam pressure
constantly tending to press its piston inwards. I provide also a cylindrical slide
worked from an eccentric on the crank shaft, this slide in each case governing
ports whereby steam is first admitted under the smaller pišton, then passed to the
Jarger cylinder above its piston and finally discharged into the cavity of the casing.
Thus the smaller piston during its instroke is subjected to pressure inwards, the
pressure on both sides of it being balanced during its outstroke, during which the
steam is being discharged from the larger cylinder.
The accompanying drawing is a section through the slide, the small or high
pressure cylinder, and part of the larger or expansion cylinder arranged according
to my invention. The connecting rod A may be spherically jointed as shewn to
the low pressure piston B, or it might be jointed with a pin passing through an eyo
in the usual way, and in like manner the rod D which works the slide F from an
. eccentric may be jointed to the slide.
The piston C of the small cylinder has a rod E, which may simply. butt against-
the larger piston B, but is preferably attached to it by a collar as shewn at e with
certain freedom of jointing to allow for slight errors of eccentricity of the two
cylinders.
The slide F is cylindrical with passages through its end as indicated by the dotted
lines at The front of the slide is larger in area than the hinder end so that there
is always a pressure urging the slide forwards and so imposing a thrust strain upon
the slide.rod. The steam or working fluid is supplied from the passage G to an
annular cavity g surrounding the slide, from which cavity it has free communication
by a passage H to the hinder end of the small cylinder, so that there is always full
pressure on the piston C tending to force it forwards.
The slide F governs the port K leading to the front end of the small cylinder
and the port L leading to the hinder end of the large cylinder. When the slide
moves backward it first closes L then it puts K in communication with g and
finally it uncovers L putting it in communication with the space 'M. In this
condition the pressure on both sides of the piston C is equal, and the pressure
behind the piston B being relieved by the escape of the exhaust through L to M,
the pistons are moved back by the action of the crank to which they are connected,
fluid entering the small cylinder in front of the piston C. When the slide moves

page_text: forward again it closes the communication from L to M and from 9 to K, and
puts K and L in communication as shewn in the drawing. The full pressure now
acts on the back of the piston C whilst the fluid in front of it loses pressure as it
expands into the larger cylinder and acts on the back of the piston D. Both
pistons are thus propelled imparting power to 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
•
The combination of a small or high pressure cylinder with a larger or expansion
cylinder single acting and in line with the small cylinder, and a slide and ports so
arranged that whilst the full pressure acts constantly on the back of the smaller
piston, it acts on its front during the backstroke, the larger cylinder then
discharging exhaust, and, during the forward stroke, the fluid that had acted in
front of the smaller piston expands into the larger cylinder acting on the larger
piston, substantially as herein described.