IMPROVEMENTS IN THE EXPANSION GEAR OF STEAM ENGINES
Year: 1880

page_text: LETTERS PATENT to Adam Dobson, of Belfast, in the County of Antrim, in
Ireland, Engineer, for an Invention of "IMPROVEMENTS IN THE EXPANSION
GEAR OF STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said Adam Dobson at the Office
of the Commissioners of Patents on the 18th Juno 1880.
ADAM DOBSON, of Belfast, in the County of Antrim, in Ireland, Engineer.
"IMPROVEMENTS IN THE EXPANSION GEAR OF STEAM ENGINES."
My Invention consists in an improved arrangement of the parts of a steam
engine for actuating the cut off, and other valves connected with the same.
For this purpose I employ a loose sleeve, which slides on a bar, spindle, or rod,
and carries with it a loose piece that, by its own gravity or assisted by a spring,
and as the sleeve slides along, drops into a slit or groove cut into the bar, spindle,
or rod, and thereby opens the cut off or other valve. The loose picco is thrown out
of the slit or groove by means of adjustable levers attached to the sleeve' and
connected with the governor, but the same operation may be effected by the use of
a wedge or inclined plane actuated by the governor.
The position of the levers, wedges, or inclined planes is varied according to the
load on the engine by the governor in the usual manner.
This arrangement may be applied with facility to existing engines.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Adam Dobson in the Great Seal Patent Office on the 15th December
1880.
ADAM DOBSON, of Belfast, in the County of Antrim, in Ireland, Engineer.
"IMPROVEMENTS IN THE EXPANSION GEAR OF STEAM ENGINES."
My Invention has reference to the cut off and other valves connected with a
steain engine, and consists in an improved arrangement of the parts, whereby the
same are to be actuated.
For this purpose I employ a loose sleeve, which slides along a bar, spindle, or
rod, and is actuated by a lever and link attached to the eccentric rod.
The bar, spindle, or rod is attached to the valve spindle, and is provided with a
slot or groove, into which, as the loose sleeve slides along a loose piece or key
carried by the loose sleeve, drops by its own gravity or assisted by a spring, and
the bar, spindle, or rod and valve spindle are thereby actuated and moved along
with the loose sleeve, and the steam valve is opened and steam admitted to the
cylinder.
In order to close the valve and shut off the steam I employ a lever or levers
attached at one end to the loose sleeve, and at the other end to the governor rod,
and acting upon a snug or pin on the loose piece or key, by which the loose piece
or key is thrown out of the slot or groove.
As the governor rod falls or rises the steam valve is closed by the aid of a spring
at short or long intervals, according to the load on the engine.
The loose piece or key may also be thrown out by the use of a wedge or inclined
plane actuated by the governor.
The position of the levers, wedges, or inclined planes is varied according to the
load on the engine by the governor in the usual manner.
For the purpose of applying my Invention to Stamper, Cornish, or double beat
valves, instead of the lever and link attached to the eccentric rod, I attach the
loose sleeve to the arm on the valve rod or lifting bar, and I employ a spring to
drive the loose piece or key into the slot or groove on the bar, spindle, or rod,
which is cottered in this arrangement to the valve spindle.
I may vary the application of my Invention as described in the preceding
paragraph by attaching the loose sleeve to the valve rod or lifting bar instead of
to the valve spindle. In this arrangement the valve rod or lifting bar is made in
two parts, the lower part carrying the loose sleeve, which is cottered to it, and
receives freely the upper part, which is furnished with the slot or groove, and
corresponds to the bar, spindle, or rod in the arrangement previously described.
And in order that the said Invention may be more fully understood, I shall now
proceed to refer to the Drawings upon the Sheet hereunto annexed, the same
letters of reference being used throughout all the Figures to indicate the same or
corresponding parts of my apparatus.
Fig. 1 is an elevation of the apparatus as applied to the Corliss steam valve.
Fig. 2 is a front elevation of the apparatus as applied to the Stamper, Cornish,
or double beat valves.
Fig. 3 is a vertical section of the arrangement shewn on Fig. 2.
Fig. 4 is a plan in section of the arrangement shewn on Figs. 2 and 3.
Fig. 5 is an elevation in section of the apparatus as applied to the valve rod or
lifting bar.
Fig. 6 is a front elevation in section of the apparatus as applied to flat or slide
valves.
Fig. 7 is a plan of the arrangement shewn on Fig. 6.

page_text: Fig. 8 is an elevation in part section of the apparatus to which the wedge or
inclined plane is applied.
Fig. 9 is a plan of the arrangement shewn on Fig. 8.
Fig. 10 is a transverse section of the arrangement shewn on Fig. 8.
Fig. 11 is a transverse section of the loose sleeve with loose piece or key; and
Figs. 12 and 13 are an elevation and plan respectively of the loose pieco or
key.
a is the loose sleeve; b is the loose piece or key; c is the lever, wedge, or
inclined plane; d is the bar, spindle, or rod having the slots or grooves e, e, to
receive the loose piece or key b; d' is the valve spindle; fis the governor rod;
g is a spring to drive in the loose piece or key; h is the lower part of the valve
rod or lifting bar, to which the loose sleeve a is cottered; & is the remaining or
upper portion of the valve rod or lifting bar furnished with the slot or groove, and
corresponding to the bar, spindle, or rod d; laud m are the lever and link
respectively attached to the eccentric rod, and actuating the loose sleeve a off the
eccentric rod; and n is the arm on the valve rod or lifting bar actuating the loose
sleeve a, according to the arrangement hereinbefore secondly described.
Having now described the nature of the said Invention, and in what manner
the same is to be performed, I would have it to be understood that I do not claim
the exclusive use of a loose sleeve, loose piece, or key, and slotted or grooved bar,
spindle, or rod, except when the same are constructed specially and employed. for
the regulation of the admission and cut off of steam, as herein before described, nor
do I claim the use of valves, valve lifter, or spindle, bars, spindles, or rods, arms,
and connecting rods, levers, wedges, inclined planes, or links, nor of any of the
separate mechanical parts which form the compound automatic apparatus employed
by me, but I claim,―
1st. The use in steam engines of a slotted or grooved bar, spindle, or rod arranged
with a loose sleeve carrying a loose piece or key, substantially as hereinbefore
described and shewn in the Drawings hereunto annexed.
2ndly. The use in steam engines of a loose sleeve carrying a loose piece or key,
and constructed, actuated, and employed substantially in the manner and for the
purposes herein before described and shewn in the Drawings hereunto annexed.
3rdly. The actuation of cut off and other valves connected with a steam engine
by the aid of a loose sleeve and loose piece or key constructed and employed
substantially as herein before described and shewn in the Drawings hereunto
annexed, and
4thly. The combination and arrangement of parts constituting the compound
automatic apparatus hereinbefore mentioned constructed and applied substantially
in the manner and for the purposes hereinbefore described.
In witness whereof, I, the said Adam Dobson, have hereunto set my hand
and seal, this Thirteenth day of December, in the year of our Lord One
thousand eight bundred and eighty.
ADAM DOBSON. (L.S.)