Year: 1896

page_text: We, JOHN MCLAREN, and HENRY MCLAREN of the Midland Engine Works Leeds,
Yorkshire Engineers do hereby declare the nature of this invention to be as
follows:-
Our invention is for improvements in governors for steam engines and other
purposes.
These improvements apply to centrifugal governors fixed upon a revolving
shaft, which are sometimes known or referred to as "shaft governors." They
consist of
1st. In arranging a dashpot of any approved form in such a way that as the
governor weight approaches the centre of the shaft upon which it revolves, the
piston rod shall be in a state of compression, and its piston travelling towards
the bottom of its cylinder, namely the end opposite to the stuffing box. Preferably we
fix the dashpot cylinder to the governor casing on the side of the shaft opposite to
the weight to which it is coupled. When the governor is standing the weight is at
rest in a position nearest to the shaft, and the dashpot piston is at or near the bottom
of its cylinder. But when the governor is caused to revolve and the weights fly out
by centrifugal force, the dashpot piston moves towards the opposite end of its cylinder
and as the effective area of the said piston is greater below than above owing to the
displacement of the piston rod, the oil or other fluid with which the dashpot is
charged flows readily from the top to the bottom side of the dashpot piston
without undue strain, and the action of the governor is thereby rendered more certain
and sensitive.
2nd. In shaft governors, in order that the lead of the slide valves of the engine
may be varied or adjusted, without making any alteration in the construction of the
governor, we fix the "pendulum arm" to which the eccentric is attached upon an
eccentric stud or pin, by means of which the centre upon which the said pendulum
arm swings may be brought nearer to or further from the centre of the shaft round
which the said eccentric revolves.
Dated this Eighth day of September, One thousand eight hundred and

page_text: JOHN MCLAREN, and HENRY MCLAREN Midland Engine Works, Leeds, Yorkshire,
Engineers do hereby declare the nature of this invention and in what inanner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:-
This invention has for its object to provide a more efficient and sensitive method
of steadying the weights of steam engine governors under varying conditions of speed
and strength of springs; and to provide a simple method whereby the lead of the
slide valve of the steain engine may be varied or adjusted.
The invention applies to centrifugal governors revolving upon a horizontal shaft,
so arranged that by a combination of weights and springs the travel of the slide valve
is regulated so as to admit the proper amount of steam to the cylinder of the steam
engine which is necessary to develope the power required.
Under varying conditions of load, the tendency of the engine is to run too fast
when the power required is suddenly reduced, and to run too slow when the power
or work to be done by the engine is suddenly increased.
As the speed of the engine increases the weights of the governors have a tendency
to fly outwards by centrifugal force, and as the speed decreases the centrifugal force
acting upon the weights is reduced, and they are then drawn back in the direction
of the centre of the shaft by means of springs. By an arrangement of levers and
dies, the travel of the slide valve of the engine is increased or diminished
relatively to the position of the governor weights, and the admission of steam to the
cylinder and consequent power developed by the engine is proportionally increased
or diminished.
In the absence of some steadying or regulating mechanism, the tendency of the
weights and springs would be to act too suddenly, and, either by means of the
centrifugal force acting in one direction or the pull of the springs acting in the other
direction too quickly the irregular running of the engine would be accentuated.
According to this invention a cataract cylinder or dashpot of any approved
construction is employed, fixed in any convenient position npon the governor casing,
but so arranged with regard to the weights it has to control or steady that as the
engine slows down and the weights approach the centre of the shaft, the piston rod
of the cataract cylinder shall be in compression, and the piston thereof shall in
consequence be pressing upon the fluid in the cataract or dashpot cylinder in the
direction away from the centre of rotation. By this means we not only get advantage
of the ordinary flow of the fluid from one side of the dashpot piston to the other, but
in the case of minute variations of speed we obtain the momentary advantage of a
certain "suck" or vacuum upon one side of the dashpot piston, which it is one object
of this invention to utilise. We also secure the further advantage that when at work
under normal conditions the balance of pressure upon the dashpot piston is in the
direction of compressing the fluid in its cylinder, instead of in the opposite case
tending to waste it by forcing it out through the stuffing box gland. Another
advantage of this arrangement is that owing to the displacement of the piston rod,
the effective area of the dashpot piston is greater at one side than at the other, so
that the oil or other fluid with which the cylinder is charged flows readily from one
side of the piston to the other, without undue strain, and the action of the governor
is thus rendered more certain and sensitive.
In order to vary when necessary the lead of the slide valve, the "pendulum arm"
upon which the eccentric is mounted is fixed at its outer end upon an eccentric pin
or stud, so that as this is moved round, the point of suspension is moved nearer to or

page_text: further away from the centre of rotation of the shaft upon which the governor is
mounted, and the lead of the slide valve is thereby increased or diminished.
Figure 1 of the accompanying drawing shews a governor constructed according to
this invention. It consists of a metal casing A. A. A. keyed upon an axis B. The
pendulum arm C. C. C. carrying the eccentric for working the slide valve is suspended
from a pin G. The weights D. D. are pivoted upon their pins GG". The dotted
lines shew the weights at D' D' in their position when the engine is at rest.
The cataract, or dashpot cylinder is shewn at E and the piston when the weights
are out is shewn at F, but when the weights are in the piston moves in the direction
of the arrow into the position F. Figures 2 and 3 shew the construction of the
suspension pin G. The portion of this pin G¹ upon which the pendulum arm hangs
is turned eccentric to its two ends G. G so that when the pin is turned round in its
bearings at each end the pendulum arm is caused to advance or recede towards or
away from the axis B.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what we
claim is
1st. In governors for steam engines the provision of a cataract cylinder or dashpot
so arranged that as the governor weights approach the centre of the engine shaft
upon which it revolves, the dashpot piston rod shall be in a state of compression and
its piston travelling towards the end of its cylinder furthest from the centre of the
crank shaft substantially as hereinbefore described.
2nd. In governors for steam engines suspending the pendulum arm upon an
eccentric stud substantially as herein before described.
Dated this Fourth day of June 1897.
JOHN MCLAREN.
HENRY MCLAREN.