Improvements in and relating to Speed Regulating and Cut-off Mechanism for Steam or other Motive Power Engines.
Year: 1891

page_text: Date of Application, 6th Apr., 1891
Complete Specification Left, 25th Nov., 1891-Accepted, 30th Jan., 1892
PROVISIONAL SPECIFICATION.
Improvements in and relating to Speed Regulating and Cut-off
Mechanism for Steam or other Motive Power Engines.
I, THOMAS STODDART, of 212 Magdala Terrace, Galashiels, Roxburghshire,
Engineman, do hereby declare the nature of my invention to be as follows:-
:-
This invention has reference to and comprises a new or improved construction or
arrangement and combination of the parts of mechanism for being placed between
the governor and the throttle or cut-off valves of steam or other motive power
engines for the purpose of automatically regulating the working speed and also
arrangements whereby these valves can be instantaneously closed and the steam
supply shut off, and the engine stopped from any part of the works, when this is
desired.
The improvements essentially consist in mounting a vertical oscillating or moving
lever or organ fulcrumed preferably near its centre or back end to the engine frame
or other stationary part. This lever which I shall term the governor lever would
be connected by a rod or other connection to the governor, and is formed at its one
or front end of a stepped curved or equivalent shape projecting downwards so that
it can have two actions as hereinafter described. I also mount or fulcrum in
horizontal line with the axis of this lever, another oscillating or moving lever or
organ which I shall term the cut-off lever of segmental or other shape, which is
connected at its back end, or at one or more parts by links or rods to the throttle or
cut-off expansion valve of the engine. This lever is also formed of a stepped
curved or equivalent shape at its front end in the inverse or converse direction to
that of the first named lever, so that the latter can move up against it to have two
actions. In the normal speed position of working, the point or other curved
projecting surface of the cut-off lever would work over and be oscillated by the
upper stepped curved surface of the governor lever, and which I term the first
position of the two levers. But when the governor rose too high by increase of
speed its rod connection would move the governor lever, so that its under curved
surface would come under the second stepped curved part of the cut-off lever, and
move this up with an increased leverage and travel sufficient to accelerate the speed
of or close the valve which this lever actuated, and by this means automatically
regulate the speed of the engine. The cut-off lever would be weighted to bring it
back to its normal position when moved by the governor lever, and this latter would
be fitted with a weight or spring to counterbalance same.
By a further improvement I can control the cut-off lever from any part of the
works, so as to instantaneously close the throttle or cut-off valve and shut off
the steam supply should anything go wrong with the machinery. This would be
effected under one arrangement by a disc or eccentric mounted on a stud behind or
below the path of the cut-off lever, and attached to a rod having a counterweight
or spring at its opposite end where it would be held up by a bar or support. This
bar or support would have a switch or other connection either mechanically or
electrically to an office or any part of the works, so as to be moved when desired,
and allow the weighted or spring rod to drop, and by this means oscillate or move
the cut-off lever sufficient to instantaneously close the valve and shut off the steam
supply, and thereby stop the engine.
1001
W. R. M. THOMSON & Co.,
Glasgow. Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Speed Regulating and Cut-off
Mechanism for Steam or other Motive Power Engines.
I, THOMAS STODDART 212 Magdala Terrace Galashiels Roxburghshire Scotland
Engineman, 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 has reference to and comprises a new or improved construction or
arrangement and combination of the parts of mechanism to be placed between the
governor and throttle or cut-off valves of steam or other motive power engines for
the purpose of automatically regulating the working speed-and also arrangement
whereby these valves can be instantaneously closed and the steam or other motive
power be shut off and the steam engine or other prime mover instantly stopped
from any part of the works when this is desired.
The special feature of my invention is in the alteration of the ratios of the levers
between the governor proper and the throttle or cut-off valves to steam engine or
other prime mover by means of and simultaneous with the action of the governor
itself thus giving an ever increasing or decreasing motion to the valve rod as
compared with that of the governor. I do not bind myself to any particular form
of mechanism as I can attain this result by various arrangements of levers, wheels
or cams as described below and shown on accompanying drawings but preferably |
adopt the first mentioned arrangement Fig. 1 as being simpler in combination with
the throwing off apparatus afterward described. My improvement essentially
consists in mounting two oscillating or moving levers A & B Fig. 1 having their
fulcrums fixed to the eugine bed or other stationary part.
These levers may be placed vertically, horizontally or diagonally as desired and
may be of any required shape. The ends of these levers lying on or near the line
of axis between the two fulcrum points I form into a stepped, curved or equivalent
shape converse to one another and so formed that they rest one on the other and
have always a single point of contact. When moved in any direction the lever
ends work together and the point of contact is constantly shifted nearer to the one
fulcrum and further from the other thus quickly altering the ratios of the levers
one to the other. The lever A Fig. 1 which I shall term the governor lever has an
adjustable weight for balancing the 2 levers with all connecting rods or links
between lever B and valve.
It has also a connection (between fulcrum and shaped end or at other desired
point) to governor by which it is worked.
The other lever B Fig. 1 which I shall term the cut-off lever is connected
directly by rods or otherwise to the throttle or cut-off valves of engine' or other
prime mover and I fix an adjustable weight at some point between the valve and
lever which keeps the rods in tension and prevents loss of motion between the valve
or valves and lever.
The operation is as follows. When the engine or other prime inover is running
at its normal speed and the governor in mid position the point of contact between
the levers A & B is near the centre of their shaped curved or equivalent shaped
ends the levers being free to nove with the governor.
If the speed of engine or other prime mover alters and the governor rises or falls
the lever A is at once acted on and through it the lever B and the valve rods
correspondingly moved; the point of contact however due to the movement of the
levers being constantly shifted nearer the one and further from the other fulcrum
of the 2 levers the movement imparted to the valve rod is in a constantly increasing
or diminishing ratio to the movement of the governor.
By a further improvement I can control the cut-off lever from any part of the
works, so as to instantaneously close the throttle or cut-off valve and shut off the

page_text: steam supply should anything go wrong with the machinery. This would be
effected under one arrangement by a disc or eccentric mounted on a stud behind or
below the path of the cut-off' lever, and attached to a rod having a counterweight
or spring at its opposite end where it would be held up by a bar or support. This
bar or support would have a switch or other connection either mechanically or
electrically to an office or any part of the works, so as to be moved when desired
and allow the weighted or spring rod to drop, and by this means oscillate or move
the cut-off lever suflicient to instantaneously close the valve and shut off the steam
supply and thereby stop the engine.
Fig. 2 shows another arrangement whereby the same results cau be obtained.
The levers A & B correspond to the similarly marked levers in Fig. 1 A being
the governor and B the cut-off' lever.
slot.
The end of lever A instead of being formed as shewn in Fig. I has a longitudinal
Lever B has a corresponding slot and these are connected together by means
of the pin C which is fixed into the end of a 3rd lever D the other end of lever D
turns on a fixed pin at a point E.
As the governor rises or falls the pin C slides in the slots either towards B or A
and imparts direct movement to lever B and at the same time alters the ratios of
the levers one to the other.
Fig. 3 shows another arrangement of levers for accomplishing same purpose.
The levers A & A & B & B₁ correspond to the levers A & B in preceding figs.
One end of lever A. & A' is jointed to a sliding block Con end of governor rod
working between 2 fixed guides D. The other ends of levers A & A are jointed
to ends of levers B & B at F & F and form what is generally termed a toggle
joint. The dotted lines show position of levers when the governor is at rest: the
full lines when governor is at its highest point. As the governor rises the governor
rod E is depressed and causes the ends F of levers A & A' to spread outwards until
they approach a straight line passing through the centres of the three joints. The
movement imparted to ends of levers B rapidly increases as the governor rod
descends and the movement gradually diminishes as the governor rod ascends.
Fig. 4 shows arrangement of curved cams and
Fig. 5 arrangement of toothed segments for obtaining the same result.
Having thus described the nature of my said invention and the manner of
performing the same I have to state that I do not bind myself to the precise details
herein described or delineated but what I consider novel and original and therefore
claim as the invention secured to me by the hereinbefore part recited Letters
Patent is―
The general arrangement and combination of the parts of mechanism as levers,
wheels, toothed segments or cams between the governor and the throttle or cut-off
valve of steam engine or inlet valves to other prime movers so as to impart by
means of the governor itself and simultaneously with its action an ever increasing
or diminishing travel to the valve rod according as the governor rises or falls.
Dated this Sixteenth day of November 1891.
THOMAS STODDART.