IMPROVEMENTS IN EXPANSION GEAR FOR WORKING AND REGULATING THE EXPANSION OR CUT-ORE VALVES OF STEAM ENGINES
Year: 1873

page_text: LETTERS PATENT to Robert Asquith, of Meanwood Road Foundry,
Leeds, in the County of York, Engineer, for the Invention of
"IMPROVEMENTS IN EXPANSION GEAR FOR WORKING AND REGULATING THE
EXPANSION OR CUT-ORE VALVES OF STEAM ENGINES
"
.
PROVISIONAL SPECIFICATION left by the said Robert Asquith at the
Office of the Commissioners of Patents, with his Petition, on the
19th April 1873.
I, ROBERT ASQUITH, of Meanwood Road Foundry, Leeds, in the
County of York, Engineer, do hereby declare the nature of my said
Invention for "IMPROVEMENTS IN EXPANSION GEAR FOR WORKING AND REGU-
LATING THE EXPANSION OR CUT-OFF VALVES OF STEAM ENGINES," to be as
follows:-
:-
In working steam at high pressures expansively it is desirable to have
perfect control over the admission of the steam, however variable the
pressure or irregular the amount of power required to be driven. In
these improvements the ordinary slide valve of a steam engine is actuated
by an eccentric on the fly wheel shaft in the usual well known manner.

page_text: The expansion valve also receives its motion from the fly wheel shaft,
but by means of a toothed wheel fixed upon the said shaft.
Upon another shaft parallel to the said fly wheel shaft a wheel of
equal diameter and equal number of teeth is also mounted, but is free to
revolve along with this second shaft or spindle. A crank pin, or stud,
or cam, is secured in a radial slot in this second toothed wheel, and the
expansion valve and rod are coupled or jointed to the same. Motion is
communicated to this second toothed wheel by the introduction or use
of a geared wheel or pinion gearing into the two wheels. This pinion
revolves on a stud fixed to a sliding block or carriage working in a
groove or guide fixed equidistant between the centres of the two toothed
wheels. The valves being set or adjusted in proper working order the
centres of these wheels will be in line.
The governors are connected in any convenient manner to the sliding
block or carriage which carries the pinion or intermediate toothed wheel,
and which is thus raised above or lowered below the two fixed centres
upon the slightest variation of speed arising from increase of pressure
or variation of load, and regulates the admission of steam by moving the
cut-off valve backward or forward, as the line of centres is varied by
the raising or lowering of the intermediate pinion or toothed wheel.
The raising or lowering of the toothed wheel which carries the crank
pin, stud, or cam, will have the same regulating power if connected
directly to the governors, and without any intermediate toothed wheel or
pinion. Or to accomplish the same purpose two bevel wheels may be
used, the driving wheel being keyed fast upon the fly wheel shaft, and
a similar one having an eccentric fixed to it, but free to revolve upon
the said shaft, these wheels being a suitable distance apart, and facing
cach other admit of the use of a pinion working into the same, and by
suitable appliances it can radiate sufficiently to vary or regulate the
degree of expansion, and have the same effect as the arrangement
previously described.
Economy of steam and uniformity of speed are thus accomplished at
the same time by means of the herein-before described automatic vari-
ahle expansion motion.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Asquith in the Great Seal Patent Office
on the 18th October 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
ASQUITH, of Meanwood Road Foundry, Leeds, in the County of York,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of April, in the year
of our Lord One thousand cight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for. Herself, Her heirs and successors,
give and grant unto me, the said Robert Asquith, Her special license
that I, the said Robert Asquith, my executors, administrators, and
assigns, or such others as I, the said Robert Asquith, my executors,
administrators, or assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
EXPANSION GEAR FOR WORKING AND REGULATING THE EXPANSION OR CUT-OFF VALVES
of Steam Engines," upon the condition (amongst others) that I, the said
Robert Asquith, my executors or administrators, by an instrument in
writing under my hand, and seal, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert Asquith, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say :-
My said Invention relates to improvements in expansion gear for
working and regulating the expansion or cut-off valves of steam
engines.
In working steam at high pressures expansively it is desirable to have

page_text: perfect control over the admission of the steam, however variable the
pressure or irregular the amount of power required to be driven.
In these improvements, which are illustrated in side elevation and
corresponding plan at Figures 1 and 2 of the annexed Sheet of Drawings,
the ordinary slide valve of the steam engine is actuated by an eccentric
(not shown in my Drawings) on the fly wheel shaft A in the usual well
known manner. The expansion or cut-off valve (the rod or spindle of
which is shewn at B) also receives its motion from the fly wheel shaft A,
but by means of a toothed wheel C fixed upon the said shaft.
Upon another shaft or stud D parallel to the said fly wheel shaft A
a wheel E of equal diameter and equal number of teeth is also mounted
so as to revolve along with this second shaft or spindle. A crank pin or
stud F or a cam is secured in a radial slot in this second toothed wheel
E, and the rod B of the expansion or cut-off valve is coupled or jointed
to the said crank pin or stud F. Motion is communicated to this second
toothed wheel E by the introduction or use of an intermediate geared
wheel or pinion G gearing into the two wheels C and E simultaneously.
This pinion G revolves on a stud H. fixed to a sliding block or carriage
I, working in a groove or guide K fixed equidistant between the centres
of the two toothed wheels. The valves being set or adjusted in proper
working order the centres of these three wheels will be in line.
The governor is connected by the spindle L or in any convenient
manner to the sliding block or carriage I which carries the pinion or
intermediate toothed wheel G, and which pinion is thus raised above, or
lowered below, the two fixed centres A and D upon the slightest variation
of speed, arising from increase of pressure or variation of load, and
regulates the admission-of-steam by moving the cut-off valve backward
or forward, as indicated by the radius line a, a, shown in red in
Figure 1, according as the line of centres is varied by the raising or
lowering of the intermediate pinion or toothed wheel G.
The raising or lowering of the tooth wheel E which carries the crank
pin, stud, or cam, will have the same regulating power if connected
directly to the governor, and without any intermediate toothed wheel or
pinion. Or the same purpose may be accomplished by employing two
bevel wheels, the driving wheel being keyed fast upon the fly wheel
shaft, and a similar one having an eccentric fixed to it, but free to
revólve upon the said shaft. These wheels being at a suitable distance

page_text: apart, and facing each other admit of the use of a pinion working into
the same, and by suitable appliances the said pinion can radiate
sufficiently to vary or regulate the degree of expansion, and have the
same effect as the arrangement previously described.
Economy of steam and uniformity of speed are thus accomplished at
the same time by means of the herein-before described automatic vari-
able expansion motion.
Having now described and particularly ascertained the nature of my
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider
to be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,―
First. The peculiar combinations and arrangements of gearing for
working the expansion or cut-off valves of steam engines, substantially
as herein-before described and illustrated by my Drawings.
Second. The varying the position of the centre of a toothed wheel
(which either directly or indirectly transmits motion to a cut-off or
expansion valve) by the aid of a governor during the rotation of such
wheel in such a manner as that the said valve shall be set forward or
backward, so as to cut off the steam at any part of the stroke most
desirable for the time being, substantially as herein-before described.
In witness whereof, I, the said Robert Asquith, have to this my
Specification set my hand and seal, this Fifteenth day of
October One thousand eight hundred and seventy-three.
ROBERT ASQUITH. (L.S.)