IMPROVEMENTS IN ROTARY ENGINES
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents, with his Petition, on the
3rd May 1872.--A communication from abroad by Gideon Black..
burn Massey, of the City, County, and State of New York, United
States of America.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for " IMPROVEMENTS IN ROTARY ENGINES," to be as follows:-
This Invention relates to the class of steam engines which impart
motion without the use of a crank, and consists mainly in the con-
struction of the cylinder and piston wheel, and in the construction
and arrangement of the pistons, whereby the pistons are kept stationary
in the revolving wheel while under steam pressure, or while doing their
work, and also in the oval cam groove and flexible cam blocks on the
pistous, the construction and arrangement of parts being as herein-after
more fully described.
In the accompanying Drawing Figure 1 represents a vertical section
-
Q. Figura 9 in a trantical

page_text: section of Figure 1 taken on the line y, y, Figure 1. Similar letters of
reference indicate corresponding parts.
A is the cylinder, which is stationary on the bed B; C is the piston
wheel; D is the shaft to which the wheel C is attached; E, F, and G
represent the pistons, which are made to slide radially with the centre of
the shaft through the rim of the revolving wheel C by means of an
eccentric or cam groove II on each of the heads I, 1, of the cylinder.
The arrangement of the pistons is scen in Figure 2, the inside of one of
the heads being represented when looking to the right from the line y, y,
of Figure 1. J represents flexible cam blocks or heads, cach attached
by a single pivot to the pistons, so that they adjust themselves to the
varying form of the cam groove as they are revolved around its oval
centre K; L is the induction port, and M is the eduction or exhaust
port. The pistons move in the direction indicated by the arrow in
this example of the Invention, but the construction may be reversed
by converting the induction port into an exhaust port, and vice versa.
There are various well known valve arrangements for that purpose.
As scen in Figure 2 the piston E is taking steam. When the piston F
in moving forward leaves the circle N of the cylinder, the steam between
the two pistons E, F, will be exhausted. The circle N and all the
circular lines between it and the shaft D are described from the centre
of the shaft, so that while a piston is under steam pressure and doing
its "work in passing over the circle N it is simply carried along or
guided by the wheel; it is not affected in any manner by the cam,
and has no sliding motion. O is a small plate of flexible or metallic
packing attached to the ends of the pistons, so connected that the
pressure of the steam will force it to the circle N, and form a steam
joint while the piston is passing over that circle; P represents sınall
recesses in the periphery of the piston wheel which receive these pack-
ing plates as the pistons occupy the position of the piston G. This
allows the wheel C to pass with the pistons beneath the stationary
packing piece Q. This packing piece Q is attached to the cylinder so
that it turns as upon a hinge as it is pressed down upon the wheel
by the steam so as to make a steam -tight joint at the top of the
cylinder. As seen in the Drawing this piece is arranged for a rever-
sible engine; R is a fly wheel; S is the driving pulley; T, T, are boxes
in the heads of the cylinder, set up to the shaft by means of the
screw U; V, V, are stuffing boxes in the heads of the cylinder; Z is
a driving pulley for the governor.
"

page_text: I propose to use a cut-off with this engine where the nature of the
case requires it, the cut-off valve being actuated by a cam W on one
end of the shaft, and a bell and crank connected with the valve rod, as
seen in Figure 2.
Referring again to the operating parts of the engine it will be seen
that the wheel C is revolved eccentrically with the interior of the
cylinder. The cam blocks J are connected with the pistons, as seen in
Figure 1, and so that they enter the stationary cam groove H, which
groove alternately pushes out and draws in the pistons through the
wheel, but keeps them stationary with the wheel while they pass over
the circle N, as before stated.
By the above-described arrangement I overcome an obstacle which
has hitherto been met with in the use of rotary steam engines, and that
is the sliding of the piston while it is under steam pressure and doing its
work.
I do not confine myself to any particular mode of packing for making
the joints steam-tight, nor to the precise form or arrangement of any
of the parts described, as they may be varied in many ways without
departing from the Invention.