IMPROVE- MENTS IN THE METHOD OF WORKING STEAM ENGINES AND OTHER MOTORS EXPANSIVELY.
Year: 1879

page_text: LETTERS PATENT to John Cole Chapman, Engineer, of 123, Cottenham Road,
Hornsey Rise, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN THE METHOD OF WORKING STEAM ENGINES AND OTHER MOTORS
EXPANSIVELY.'
"
PROVISIONAL SPECIFICATION left by the said John Cole Chapman at the
Office of the Commissioners of Patents on the 5th April 1879.
JOHN COLE CHAPMAN, Engineer, of 123, Cottenham Road, Hornsey Rise, in the
County of Middlesex. IMPROVEMENTS IN THE METHOD OF WORKING STEAM
ENGINES AND OTHER MOTORS EXPANSIVELY."
The main feature of my Invention as applied to an ordinary steam engine consists
in the employment of a revolving or partially revolving drum contained within a
case, which may be fitted to and form part of the governor stand or bracket, the
drum being provided interiorly with two rollers fixed parallel to each other.
Passing through the centre of the drum is a shaft, one end of which is provided
with a feather to take into a corresponding groove in a sleeve carrying a bevil
wheel, which is actuated by another and similar wheel on the main shaft of the
engine, the other end of the first mentioned shaft being furnished with collars after
the manner of a thrust bearing to form a connection with and to actuate the rod
or lever controlling the expansion valve. Fitted on and revolving with the shaft
is a disc cam, which works between the two fixed rollers on the interior of the drum
hereinbefore mentioned, the said drum containing oil for the cam to work in so as
to ensure its constant lubrication. On the outer end or prolongation of the drum
a pinion is fitted, which imparts motion from a rack to the drum.

page_text: The rack is fitted to and forms part of a vertical rod, which, by a rocking lever,
is connected with the governor spindle and thence with the arms of the governor.
By means of this connection the amount and speed of revolution of the drum are
dependent on and in proportion to the rise and fall of the governor arms, and as
the relative position of the two fixed rollers within the revolving drum to the disc
cam on the shaft traversing the drum determines the amount and time of thrust
imparted to the rod controlling the expansion valve, it will be seen that the "cut
off" of the steam is automatically controlled by the rise and fall of the governor
arms. It is obvious that my Invention may, with very slight modification, be
adapted to other motors besides steam engines whenever it is desired to work them
expansively.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Cole Chapman in the Great Seal Patent Office on the 4th
October 1879.
JOHN COLE CHAPMAN, Engineer, of 123, Cottenham Road, Hornsey Rise, in the
County of Middlesex. "IMPROVEMENTS IN THE METHOD OF WORKING STEAM
ENGINES AND OTHER MOTORS EXPANSIVELY."
The main feature of my Invention as applied to an ordinary steam engine consists,
as will be clearly understood on reference to the annexed Drawings, in the employ-
ment of a revolving or partially revolving drum a contained within a case b, which
may be fitted to and form part of the governor stand or bracket c, the drum a
being provided interiorly with two rollers d, d, fixed parallel to each other.
Passing through the centre of the drum a is a shaft e, one end of which is pro-
vided with a feather f to take into a corresponding groove g in the sleeve h
carrying a bevil wheel i, which is actuated by another and similar wheel on the
main shaft of the engine, the other end of the first mentioned shaft e being furnished
with collars j, j, after the manner of a thrust bearing to form a connection with and
to actuate the rod or lever k controlling the expansion valve k¹.
To compensate for the difference of travel between the main valve and the cut-
off valve, a "dead plate" kell is inserted, as seen in Figure 2. Fitted on and
revolving with this shaft e is a disc cam l, which works between the two fixed
rollers d, d, on the interior of the drum a hereinbefore mentioned, the said drum a
containing oil for the cam to work in so as to ensure its constant lubrication.
On the outer end or prolongation of the drum a pinion m is fitted, which imparts
motion from a rack n to the drum.
The rack n is fitted to and forms part of a vertical rod o, which is connected with
the governor spindle q by the rocking lever p and the sliding piece p¹, and thence
with the arms of the governor.
By means of this connection the amount and speed of revolution of the drum a
are dependent on and in proportion to the rise and fall of the governor arms, and
as the relative position of the two fixed rollers d, d, within the revolving drum a
to the disc cam 7 on the shaft e traversing the drum a determines the amount and
time of thrust imparted to the rod k controlling the expansion valve, it will be seen
that the "cut off" of the steam is automatically controlled by the rise and fall of
the governor arms.
It is obvious that my Invention may with very slight modifications be adapted
to other motors besides steam engines whenever it is desired to work them
expansively.
Having now described the nature of my said Invention and in what manner the
same is to be performed, I declare that I claim,-
The arrangement and combination of parts herein before described, and substan-
tially as shown in the annexed Drawings, acting as and for the purpose set forth.
In witness whereof, I, the said John Cole Chapman, have hereunto set my
hand and seal, this Third day of October, One thousand eight hundred and
seventy nine.
JOHN COLE CHAPMAN. (L.S.)