A STRAIN GOVERNOR FOR MARINE AND STATIONARY STEAM ENGINES AND OTHER MOTORS
Year: 1883

page_text: LETTERS PATENT to John Munro West Croydon in the County of Surrey,
for an Invention of A STRAIN GOVERNOR FOR MARINE AND STATIONARY
STEAM ENGINES AND OTHER MOTORS communicated to him from abroad by
George Keith of Cienfuegos in the Island of Cuba.
COMPLETE SPECIFICATION filed by the said John Munro at the Office
of the Commissioners of Patents on the 16th January 1883.
JOHN MUNRO, of West Croydon in the County of Surrey, A STRAIN GOVERNOR
FOR MARINE AND STATIONARY STEAM ENGINES AND OTHER MOTORS commu-
nicated to me from abroad by George Keith of Cienfuegos in the Island of
Cuba.
The object of this invention is to adapt the work applied by steam or other
Motors to that required by regulating the admission of steam in altering the stroko
of the engine valves or the position of special cut off valves or otherwise regulating
the action of the particular motor employed, by means of the torsional strain on its
main shaft. To explain the nature of the device I will take the case of a marino
engine: but it is to be understood that my invention is applicable to other motors
whether actuated by steam or some other source of power. I also apply it to
regulating the yield of magneto-electric machines, by moving the electromagnets to
and from the induced coils or bobbins so as to vary the intensity of the magnetic
field, or by interposing more or less resistance in the circuit of the magnets.-
Figures 1 and 2 are sectional views of the Governor as adapted for regulating
marine engines.-A. is the engine shaft with its flange a. upon the outer circum-
ference of which are attached, as shown the inner ends of two sets of spiral
springs B'. B. The two sets are wound in opposite directions and their outer
ends attached by means of bolts B'. B", to the hollow disc c. which surrounds the
flange a. and which is shrunk or keyed upon the propeller shaft D.-Upon this
shaft is fixed the eccentrics El. E. so as to act by means of suitable mechanism
upon the main or special cut off valves of the engine regulating their movements

page_text: to admit steam according to the tension on the springs by the relative movement
of the propeller and crank shafts caused by the winding and unwinding of the
springs. Figures 3. 4. and 5 are front and side views of the hollow disc with its
cover F. showing bolt holes g. g. whereby the engine and propeller shafts can at
any time when required be bolted rigidly together cutting out the action of the
Governor. Figure 6. is an enlarged view of one of the springs.-The lengths of
the springs are to be such as to allow the propeller shaft an angular movement
between the positions where the forward and backward sets are fully wound up
equal to the angular distance between the forward and backward main eccentrics
when the steam is merely to be cut off by the action of the Governor, and greater
by the amount of cushion when the steam is to be not only cut off but the pistons
cushioned. The strength of each set to be such as to equal the torsional strength
of the shaft. Application.-Figures 7. 8. and 9 represent a compound marine
engine. a. is the Governor b. is the propeller shaft upon which are fixed two spur
pinions c. cc'. is geared by means of the gearing d. to drive the loose eccentric e'.
the rod of which together with that of the forward main eccentric f¹ of the high
pressure valve is connected as shown to the forward end of the link while that of
the back main eccentric g¹. is attached in the usual manner to the backward end.
In the same manner the gearing c". d. and the loose eccentric el. are connected up
with the forward main eccentric f" of the low pressure cylinder. Figures H.P.
and L.P. show the position of the loose eccentrics e'. e". when the engine is at rest,
or when the forward and backward springs are in equilibrium, giving half travel
to the valves. At the moment of admitting steam e. e. would commence to fall
towards... until the forward set of springs were fully wound up when e'. e".
'would coincide with f'. f", and the valves would assume their full travel producing
a balance of strain between the engine and propeller shafts.-If then the strain on
the latter were removed by the propeller coming out of the water, the forward set
of springs would immediately be released and the backward would take up the
resilience of the shaft immediately bringing el. el. towards g. 9" and cutting off
the steam from both cylinders thus preventing the engine from racing and avoiding
the consequent danger and damage to the machinery and ship. In the case of
stationary engines I prefer to use one set of springs-Claim. I claim the mode of
governing steam engines or other motors and electric generators by means of the
torsional strain on their main shafts through the medium of springs eccentrics or
other connecting mechanism substantially as described. .
In Witness Whereof I the said John Munro have hereunto set my hand and
seal this sixteenth day of January in the year of our Lord One thousand eight
hundred and eighty three
JOHN MINRO