Improvements in Valve Gear for Rotary Engines.
Year: 1891

page_text: Date of Application. 22nd Jan., 1891
Complete Specification Left, 22nd Oct., 1891-Accepted, 28th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear for Rotary Engines.
I, ALEXANDER FRANCIS GARDEN BROWN of Swindridge Muir Dalry in the
County of Ayr, Gentleman, do hereby declare the nature of this invention to be as
follows
―:
This invention relates to improvements in valve gear for rotary engines and
especially for the type of such engines for which Letters Patent numbered 1555
and 16913 and dated 2nd February 1888 and 26th October 1889 respectively have
been granted to me. Under the invention, the main shaft has a spur wheel situated
on that end of it from which the valves are actuated the said wheel being geared
with a wheel preferably of larger diameter on each of the valve spindles these
valve spindles being further connected together by a chain or band passed round
sprocket wheels or their equivalents also keyed one on each of the spindles. The
wheel on the main shaft is keyed thereto by a spiral feather and groove and it is so
connected to a centrifugal or other governor that when the speed of the engine
varies the said wheel is caused to rotate faster or slower than the main shaft and so
alter the lead of the distributing valves which may be constructed as described in
the Specifications of the said previous Patents or they may be composed of two
flanges or collars mounted upon the valve spindle and the distance between which
represents the length of the valve. Between these collars loose curvilinear strips
of brass or other metal extend, the said strips being held against the valve casing
by the pressure of the steam and having spaces between them for the admission and
exhaust at the proper times.
Dated this Twenty-first day of January 1891.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in Valve Gear for Rotary Engines.
I, ALEXANDER FRANCIS GARDEN BROWN of Swindridge Muir Dalry in the
County of Ayr, Gentleman, 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:-
This invention relates to improvements in valve gear for rotary engines and
especially for the type of such engines for which Letters Patent numbered 1555
and 16913 and dated 2nd February 1888 and 26th October 1889 respectively have
been granted to me.
Under the invention which is illustrated in side elevation
(with the flange X removed) at Figure 1 on the accompanying drawings and in
horizontal section on the line a bat Figure 2 the main shaft A has a spur wheel B
situated on that end of it from which the valves are actuated the said wheel being
geared with wheels C of larger diameter on each of the valve spindles D. The
wheel B is keyed to the main shaft by a spiral feather E entered into a rifle or
spiral groove F made in the shaft A. and the wheel is so connected to a centrifugal
or other governor that when the speed of the engine varies the said wheel B is
caused to rotate faster or slower than the main shaft and so alter the lead of the
distributing valves G which may be constructed as described in the Specifications
of the said previous Patents or as more particularly seen in longitudinal section at
Figure 3 and in cross section at Figure 4 they may be composed of two flanges or
collars mounted upon the valve spindles D and the distance between which

page_text: collars represents the length of the valve. Between these collars loose curvilinear
strips y of brass or other metal extend the said strips being held against the valve
casing by the pressure of the steam and having spaces between them for the
admission and exhaust at the proper times.
The steam and exhaust ways or passages are shown. in. dotted lines at Figure 1
and by the section Figure 5 on the line mn Figure 1. The space O is in constant
communication with the steam pipe P and the space Q is in constant communication
with the exhaust pipe R, whilst on the line m n there are two spaces one of
which is in constant communication with the steam pipe P and the other Q¹ in
constant communication with the exhaust.
.
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 valve gear for rotary engines the arrangement consisting of a spur wheel
keyed to the main shaft by a rifle or screwed feather and groove said wheel being
geared with spur wheels on the spindles of the distributing valves in such wise that
when the speed of the engine varies from the normal limit the lead of the valve is
altered substantially as described with reference to the annexed drawings.
2. In a rotary engine a valve consisting of a spindle having two collars upon it
and two loose curvilinear strips bearing on said collars having spaces between them
and held against the valve casing by steam pressure each valve being actuated
by and being capable of having its lead altered from the main shaft through
gearing substantially as described.
Dated this Twenty-first day of October 1891.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.