Improvements in and relating to Electro-magnetic Marine Governors.
Year: 1887

page_text: Improvements in and relating to Electro-magnetic Marine
Governors.
I, GEORGE ALEXANDER SMITH of 64 Alexandra Street, Goole, Yorkshire, Officer in
Her Majesty's Customs, 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 :--
In the specification of my invention for An electro-magnetic Marine Governor
No. 7456 of 1886 I have described an arrangement for automatically controlling the
speed of marine engines relatively to the degree of immersion of the screw propeller.
The invention described in the specification above referred to presents two distinct
devices, connected and arranged to work in unison by a suitable electrical circuit.
The two devices consist of a dynamo-electric generator and electro-motors, fully
described on page 2 of the specification above referred to, lines 12 to 39, and also a
float arrangement, also described upon page 2 lines 40 to 57 and page lines 1 to 4.
Now, my present invention consists essentially in providing an auxiliary air chamber
to the float arrangement above referred to, and also an improved method of effecting
the variation of the electrical contacts during the rise and fall of the stern of the ship,
by reason of a head sea, or strong tideway.
In the accompanying sheet of drawings A represents a cylinder containing a float B
attached to a rod passing through the stuffing box and gland K. A pipe D com-
municates with the water level, outside the ship, by means of which an equivalent
level is maintained within the cylinder A beneath the float B, the latter being raised
with any increase of external level due to the depression of the stern of the ship, and
of course descending when the external water level is raised, relatively to the
containing cylinder A, by reason of the lifting of the vessel's stern.
In accordance with my present invention, I provide an air chamber E, connected to
the top of the containing cylinder A by means of the pipe J through the controlling
valve F, in such a manner that the elasticity of the air which is compressed by the
rising float tends to accelerate its return to the bottom of the stroke when the stern of
the vessel is lifted by the external action of the waves.
A pet-cock I serves the double purpose of regulating the elasticity due to com-
pression, and also to allow any water that may accumulate in the air chamber E to be
drawn off. A cock G is connected to the pipe D for the purpose of affording egress

page_text: to any air that may be drawn in during the pitching of the ship, and consequently
remain under the float B.
Having described the action of the float B, relatively to the variation of the external
wave line, I now refer to the corresponding electrical contacts, whereby the aforesaid
action of the float is electrically transmitted to the electro-motors described in my
specification of prior date hereto, above referred to.
The float rod C according to my invention is flattened below the full length of its
stroke, and provided with pins f, taking into the forked ends h, ', of the lever
switches H H¹, which latter are connected to the positive (+) and negative (-)
electrical leads M M¹ respectively from the dynamo. A suitable quadrant L is fitted
with contact pieces a, b, c, d and e upon which the lever switches H H¹ make electrical
contact during the upward and downward movement of the float B by means of the
pins ff upon the float rod C above described.
to
4:
The device or contrivance according to the foregoing description is put into auto-
matic electrical and mechanical action as follows, that is to say :-When the stern of
the vessel is lifted by the action of the waves to such an extent as to cause the engines
race," the float B within the cylinder A falls by reason of the descending water
level within said cylinder, such action being aided by the elasticity of the air com-
pressed in the air chamber E due to each rise of the float B within the cylinder A.
The descent of said. float B and rod C moves the switch levers H H' so that the
dynamo leads M M' makes contact with the contact pieces a and c respectively. When
however, the stern of the vessel becomes depressed by the action of the external wave
line, the float B within the cylinder A rises, moving the switch levers H H so that
they make contact with the contact pieces cand e respectively, thus reversing the
current of the dynaino through the helices of the suspended electromotors which
operate the throttle valve, as described in the specification of my invention of prior
date hereinbefore referred to. The contact pieces b and d are electrically coupled
together so that the dynamo is momentarily short circuited during the passage of the
switch levers H H¹ over the contact pieces b and d. The contact pieces a and e are
directly coupled to one terminal of the two suspended motors, and c is similarly
coupled to the other motor terminal; so that c becomes alternately (+) positive or
(-) negative according as the switch levers H or H¹ make electrical contact with it.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, 1 declare that what I
claim is
Firstly In the construction of an electro magnetic governor for marine engines,
the employment of an air chamber E of suitable construction for the purposes herein-
before described in combination with a reversible electro-magnetic arrangement
whereby the electrical current generated by a dynamo is caused to be reversed in
unison with the movement of a float substantially as herein described and set forth.
Secondly In an electro-magnetic governor, the method of and means adopted
for increasing the anticipatory automatic action of said governor by reversing the
current acting upon the electro-magnets operating the throttle valve and accelerating
the downward movement of the float by means of the elasticity of compressed air in a
suitable chamber substantially as herein described and set forth.
:-
Dated this Twenty fourth day of December 1887.