IMPROVEMENTS IN MACHINERY FOR PROPELLING VESSELS WHEN TWIN SCREW PROPELLERS ARE EMPLOYED
Year: 1864

page_text: LETTERS PATENT to Edward Humphrys, of Deptford Pier, in the County of
Kent, for the Invention of "IMPROVEMENTS IN MACHINERY FOR PROPELLING
VESSELS WHEN TWIN SCREW PROPELLERS ARE EMPLOYED."
Sealed the 30th August 1864, and dated the 1st March 1864.
PROVISIONAL SPECIFICATION left by the said Edward Humphrys at the
Office of the Commissioners of Patents, with his Petition, on the 1st
March 1864.
I, EDWARD HUMPHRYS, of Deptford Pier, in the County of Kent, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN MACHINERY FOR
PROPELLING VESSELS WHEN TWIN SCREW PROPELLORS ARE EMPLOYED," to be as
follows:-
This Invention has for its object improvements in machinery for propelling
vessels when twin screw propellors are employed. For this purpose I mount on
the shaft of each of the two screws a pair of bevilled wheels in such a manner
that they can revolve freely independently of the screw shaft. Each pair of
wheels is held in a bearing which serves as the thrust bearing of the propellor
shaft, and the wheels of each pair are driven in opposite directions by being
geared with opposite sides of a bevilled wheel on the crank shaft of the

page_text: engine. The wheels on the screw shafts can either of them be clutched with
the shaft, so as to drive the shaft forward or backward; this is done by
moving the shaft a short distance longitudinally (which is easily effected by a
lever or otherwise), and so bringing a friction disc fixed on the shaft against
another similar disc on one of the wheels. There are two friction discs on
each shaft, and by moving the shaft endwise one or other of them can be
brought against the corresponding disc on one of the wheels; or the friction
dises on the shaft can be kept out of contact with both the discs on the wheels,
and the shaft will then remain stationary. The discs are made by preference
with angular grooves and ridges, so as to ensure that they shall not slip when
driving. When it is desired that the screw shall rotate in a direction to
propel the vessel forward its shaft is moved inboard a short distance, and the
shaft is thus clutched with the wheel, which will drive it in the required
direction; the thrust of the screw then serves to press the friction surfaces
into contact with sufficient force. Similarly when the motion of the screw is
to be reversed its shaft is moved outboard a distance, this brings it into gear
with the other driving wheel; and,-as-before, the thrust of the screw keeps the
friction clutch surfaces in contact with sufficient force. This arrangement
allows of the vessel being manoeuvred and stopped whilst the crank shaft of
the engine is revolving constantly in one direction, and I am thus enabled to
employ a single steam cylinder for driving the crank shaft, which cannot
conveniently be done when the engine has to be stopped and started whilst
the vessel is under weigh.
-
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Humphrys in the Great Seal Patent Office on the
1st September 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HUMPHRYS, of Deptford Pier, in the County of Kent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of March, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Edward Humphrys, Her special licence that I, the said Edward
Humphrys, my executors, administrators, and assigns, or such others as. I, the
said Edward Humphrys, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-

page_text: "
after during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
MACHINERY FOR PROPELLING VESSELS WHEN TWIN SCREW PROPELLERS ARE EMPLOYED,"
upon the condition (amongst others) that I, the said Edward Humphrys, my
executors or administrators, by an instrument in writing under my, or their,
or one of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be per-
formed, and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that T, the said Edward Humphrys, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
This Invention has for its object improvements in machinery for propelling
vessels when twin screw propellers are employed. For this purpose I mount
on the shaft of each of the two screws a pair of bevilled wheels in such
a manner that they can revolve freely independently of the screw shaft.
Each pair of wheels is held in a bearing which serves as the thrust bearing of
the propeller shaft, and the wheels of each pair are driven in opposite
directions by being geared with opposite sides of a bevilled wheel on the
crank shaft of the engine. The wheels on the screw shafts can either of them
be clutched with the shaft so as to drive the shaft forward or backward; this
is done by moving the shaft a short distance longitudinally (which is easily
effected by a lever or otherwise), and so bringing a friction disc fixed on the
shaft against another similar disc on one of the wheels. There are two
friction discs on each shaft, and by moving the shaft endwise one or other of
them can be brought against the corresponding disc on one of the wheels; or
the friction discs on the shaft can be kept out of contact with both the discs
on the wheels, and the shaft will then remain stationary. The discs are made
by preference with angular grooves and ridges, so as to ensure that they shall
not slip when driving. When it is desired that the screw shall rotate in a
direction to propel the vessel forward its shaft is moved inboard a short
distance, and the shaft is thus clutched with the wheel, which will drive it in
the required direction; the thrust of the screw then serves to press the friction
surfaces into contact with sufficient force. Similarly when the motion of the
screw is to be reversed its shaft is moved outboard a distance, this brings it
into gear with the other driving wheel, and, as before, the thrust of the screw

page_text: keeps the friction clutch surfaces in contact with sufficient force. This
arrangement allows of the vessel being manoeuvred and stopped whilst the
crank shaft of the engine is revolving constantly in one direction, and I am
thus enabled to employ a single steam cylinder for driving the crank shaft,
which cannot conveniently be done when the engine has to be stopped and
started whilst the vessel is under weigh.
Having thus stated the nature of my said Invention, I will proceed more
fully to describe the manner of performing the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a plan partly in section, and Figure 2 a side elevation, of
machinery arranged according to my Invention, wherein the bevil wheels used
are toothed; Figure 3 shows a plan, partly in section, and Figure 4 a side
elevation of machinery arranged according to my Invention, wherein the bevil
wheels are not toothed, but act by friction. In each of these arrangements
only one steam engine is used to give motion to the driving shaft, and in each
of these arrangements the thrust of the propellers produces the frictional
contact by which the propeller shafts receive motion from the driving shaft.
In Figures 1 and 2, a and b are the two propeller shafts; c is the single steam
cylinder; d is the driving shaft, on which are fixed two bevil wheels e, e, the
teeth of which gear as desired with the teeth of the bevil wheels f, f, or g, g,
on the propeller shafts. The bevil wheels f and g when not in gear with the.
friction dises and i turn freely on the propeller shafts. The friction discs h
and i are fixed on the propeller shafts at such a distance apart that when one
of the discs h or i is in gear the other is away from its wheel; hence, according
as each of the propeller shafts is moved a short distance inboard or outboard,
and the propeller is being driven, so will be the direction of the thrust and the
friction necessary for driving each propeller shaft.
In Figures 3 and 4, a and b are the two propeller shafts; c is the steam
cylinder; d is the driving shaft, which receives motion from the steam engine.
On the driving shaft are fixed two bevil wheels e, e, which drive either of the
bevil wheels for g keyed on each of the propeller shafts. According as the
one or other of the wheels for g is brought in contact with the wheel e, and
is held in contact by the thrust of the propeller, so will be the direction in
which the propeller shaft will be driven. The bevil faces of these wheels e, c,
ff, and g, g, may be grooved or not
in like manner to what has heretofore
been practised when using friction gear. In this arrangement the thrust
bearings are applied at the ends of the driving shaft, as the pressure of the
thrust acting on the bevil wheels f, g, will tend to force the driving shaft

page_text: endways; hence the propeller shafts are simply arranged to turn in long
bearings, as shown, so as to permit the full effect of the thrust to come on the
friction surfaces of the bevil wheels where they are in contact.
In witness whereof, I, the said Edward Humphrys, have hereunto set my
hand and seal, this Thirtieth day of August, in the year of our Lord
One thousand eight hundred and sixty-four.
EDW. HUMPHRYS. (L.S.)