DISCONNECTING AND RAISING SCREW PROPELLERS
Year: 1856

page_text: LETTERS PATENT to George Alfred Lewis, of Bristol, Somerset, for the
Invention of "DISCONNECTING AND RAISING SCREW PROPELLERS."
Sealed the 1st November 1856, and dated the 4th September 1856.
PROVISIONAL SPECIFICATION left by the said George Alfred Lewis, at
the Office of the Commissioners of Patents, with his Petition, on the
4th September 1856.
I, GEORGE ALFRED LEWIS, of Bristol, Somerset, do hereby declare the
nature of the said Invention for "DISCONNECTING AND RAISING SCREW PRO-
PELLERS," to be as follows:-
The object of this Invention is to enable a screw propeller when not required
for use to be readily disconnected from the main driving or screw shaft and
raised out of the water, and, when necessary, to be again lowered by a frame
or lift, which after having deposited it in its working position may be with-
drawn out of the water, where it would otherwise form an impediment to the
vessel's way or progress. For this purpose I employ a frame or lift which slides
vertically between the stern and rudder posts. The upper extremity of this
frame terminates in a shank which passes upward through the after deck. To
this shank is jointed a strong screw passing through a nut fixed above the
deck, which nut being made to revolve by toothed gearing or other suitable
means, will raise or lower the screw, and with it the lift before mentioned.

page_text: When the lifting screw is not in use, the joint above named enables it to be
turned down so as to lie upon the deck, or it may be removed as desired.
The lower extremities of the lift are provided with pins, having their lower ends
formed with T or other suitable heads, which take into corresponding holes
formed respectively in a clutch block attached to the inner end of a short shaft
upon which the screw propeller is fixed, and a block or bearing in which the
outer end of the same shaft works. In these blocks, situated as described, at
the respective ends of the short outer shaft, are formed grooves, which fit upon
and are guided in their vertical movement by the stern and rudder posts. The
outer end of the inner or main driving shaft is fitted with a clutch block, the
feather of which corresponds in thickness with the stern post, (or that portion
of the stern post upon which the first-named block slides), with which, when in
a vertical position, it coincides. In its working position this feather takes into
the groove in the block which is attached to the inner end of the short outer
shaft upon which the propeller is fixed, and carries it round. The two blocks
are farther secured together by bolts. On its being required to raise the
propeller out of the water, these bolts are removed, and the frame or lift before
mentioned is lowered until the ends of the pins situated at its lower extremities
have entered the holes provided for them in the blocks at the ends of the short
outer propeller shaft; they (the pins) are then, by means of a rod or other
suitable connection, turned round during one-fourth of a revolution, whereby
the T heads are made to lie across the holes and prevent the withdrawal of the
pins. Hence it will be obvious that on the lift or frame being raised by means
of its screw, it will carry the short shaft and propeller with it to any required
height, where both may be secured. When necessary the propeller is again
lowered by means of the lifting screw until the before-mentioned blocks come
in contact with stops attached to the stern and rudder posts, and so placed as
to check the descent of the propeller when the centres of the inner and outer
shafts are in such a position as to coincide. The T-headed pins are then
turned so as to pass freely out of the holes in the blocks, and the frame or
lift is drawn up by the lifting screw, which is afterwards turned down on the
deck, as before described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Alfred Lewis in the Great Seal Patent Office on
the 4th March 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
ALFRED LEWIS, of Bristol, Somerset, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of September, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
George Alfred Lewis, Her special licence that I, the said George Alfred
Lewis, my executors, administrators, and assigns, or such others as I, the
said George Alfred Lewis, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all
times thereafter 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
"DISCONNECTING AND RAISING SCREW PROPELLERS," upon the condition (amongst
others) that I, the said George Alfred Lewis, 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 Inven-
tion, and in what manner the same was to be performed, 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 I, the said George Alfred Lewis, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement:-
The object of this Invention is to enable a screw propeller when not
required for use to be readily disconnected from the main driving or screw
shaft and raised out of the water, and, when necessary, to be again lowered by
a frame or lift, which after having deposited it in its working position may be
withdrawn out of the water, where it would otherwise form an impediment to
the vessel's way or progress.
For this purpose I employ a frame or lift which
slides vertically between the stern and rudder posts. The upper extremity of
this frame terminates in a shank, which passes upward through the after deck.
To this shank is jointed a strong screw passing through a nut fixed above the
deck, which nut being made to revolve by toothed gearing or other suitable
means, will raise or lower the screw, and with it the lift before mentioned.

page_text: When the lifting screw is not in use, the joint above named enables it to be
turned down so as to lie upon the deck, or it may be removed as desired. The
lower extremities of the lift are provided with pins, having their lower ends
formed with T or other suitable heads, which take into corresponding holes
formed respectively in a clutch block attached to the inner end of a short shaft
upon which the screw propeller is fixed, and a block or bearing in which the
outer end of the same shaft works. In these blocks, situated as described, at
the respective ends of the short outer shaft, are formed grooves, which fit upon
and are guided in their vertical movement by the stern and rudder posts. The
outer end of the inner or main driving shaft is fitted with a clutch block, the
feather of which corresponds in thickness with the stern post, (or that portion
of the stern post upon which the first-named block slides,) with which, when
in a vertical position, it coincides. In its working position this feather takes
into the groove in the block which is attached to the inner end of the short
outer shaft upon which the propeller is fixed, and carries it round. The two
blocks are farther secured together by bolts. On its being required to raise
the propeller out of the water, these bolts are removed, and the frame or lift
before mentioned is lowered, until the ends of the pins situated at its lower
extremities have entered the holes provided for them in the blocks at the ends
of the short outer propeller shaft; they (the pins) are then, by means of a rod
or other suitable connection, turned round during one-fourth of a revolution,
whereby the T heads are made to lie across the holes and prevent the
withdrawal of the pins. Hence it will be obvious that on the lift or frame
being raised by means of its screw, it will carry the short shaft and propeller
with it to any required height, where both may be secured. When necessary
the propeller is again lowered by means of the lifting screw until the before-
mentioned blocks come in contact with stops attached to the stern and rudder
posts, and so placed as to check the descent of the propeller, when the centres
of the inner and outer shafts are in such a position as to coincide. The
T-headed pins are then turned so as to pass freely out of the holes in the
blocks, and the frame or lift is drawn up by the lifting screw, which is
afterwards turned down on the deck, as before described.
DESCRIPTION OF THE DRAWINGS.
The accompanying Drawings, made to geometrical scales, represent a mode
in which my Invention may be carried into effect; Fig. 1 of Sheet 1 being a
side elevation, partly in section, of so much as is necessary of the after part of
a vessel, with my Invention applied thereto; the frame or lift being out of

page_text: position. Fig. 2 is a similar view representing the frame or lift in course of
being lowered to remove the propeller; Fig. 3 is another similar view shewing
the lift, with the propeller attached to it, again raised into the position shewn
at Fig. 1, the lifting screw being again turned down upon deck. The various
Figures on Sheet 2 are views of parts of the apparatus drawn to enlarged
scales; Fig. 1 being a side view of the frame or lift, with the propeller shaft,
&c. attached; Fig. 2, an edge view of the same; and Fig. 3, a plan of the
propeller shaft and blocks, shewing the manner of connecting the inner and
outer shafts, and the position of the lift pin or bolt heads when the lift is
attached to the blocks. Figs. 4 and 5 are respectively a side elevation, partly
in section, and a front elevation, of the gearing &c. for giving motion to the
lifting apparatus. The same letters are employed to designate similar parts
throughout.
The frame or lift a, sliding vertically between the stern post b, and rudder
post c, terminates in a shank d, to which is jointed, by means of the pins e, the
elevating or lifting screw f passing through the nut g, formed in the boss of
the wheel h, receiving motion from the pinion i on the shaft j, actuated by the
hand wheel k. The lower extremities of the lift a are provided with pins l,
having their lower ends formed with T heads, which take into corresponding
holes formed in the clutch block m, attached to the short shaft n, (upon which
the propeller o is fixed,) and in the block or bearing p, in which the outer end
of the same shaft works. In these blocks m and p are formed grooves which
fit upon and are guided in their vertical movement by the stern post b, and
rudder post c.
On the outer end of the inner or main driving shaft q, is
fitted a clutch block 1, the feather of which corresponds in thickness with the
stern post b, with which, when in a vertical position, it consequently coincides.
In its working position, this feather, taking into the groove in the block m,
forms the means whereby the shaft 9 is connected with the shaft n, and carries
it round; the connection being completed by screws as shewn. The spring s
attached to the rudder post, (except when forced into its recess by the descent
of the lift as herein-after described,) prevents the block p from rising, and with
the stops fixes the position of the propeller shaft n. The rods u are for the
purpose of turning the T-headed bolts 1, as herein-after explained. The action
of the apparatus, supposing the propeller to be in its working position, and that
it is required to raise it into the position shewn at Fig. 3, is as follows:-The
inner or main driving shaft q is turned so that the feather of the block r shall
stand in a vertical position, the holes in the blocks m and p intended to
receive the heads of the bolts being uppermost. The lifting screw f is now
raised into a vertical position, and carries with it the wheel h, which enters into

page_text: gear with the pinion i, and is secured in its bearing by a cap w and screws, as
shewn. The rods u are then attached to the bolts I, and by turning the hand
wheel k, a rotary motion is communicated to the nut g, thus allowing the screw
f, with the lift a attached, to descend until the heads of the pins I have entered
the holes provided for them in the blocks m and p, and the lower extremities
of the lift have come into contact with the blocks; that foot of the lift which
slides upon the rudder post having in its descent pushed back the spring s and
left the frame or lift a at liberty to be raised on the withdrawal of the screws
by which the blocks m and r are connected together. The pins or bolts / are
now, by means of the rods u, turned round during one-fourth of a revolution,
whereby the T heads are made to lie across the holes (as shewn at Figs. 2 and
3 of Sheet 2,) and prevent the withdrawal of the bolts or pins, thus securing
the feet of the lift a to the blocks m and p, and enabling the propeller to be
raised, by means of the hand wheel and gearing before described, into the
position shewn at Fig. 3 of Sheet 1, where it may be secured by a bar & placed
across or otherwise as convenient. The cap w is then to be removed and the
screw turned down upon deck or removed as desired. It is obvious that by
reversing the operation, the propeller may be again deposited in working
position, and the lift or frame a removed.
Having thus described the nature of my said Invention, and in what
manner the same may be performed, I would have it understood that I do
not confine myself to the precise details represented for carrying it into
effect; for example, chains or other suitable appliances may be employed
instead of the screw for raising and lowering the lift, &c., without departing
from the essential feature of my Invention, which enables the frame or lift
employed for raising and lowering a screw propeller to be readily detached
therefrom and removed from a position where it would form an obstacle to the
way or progress of the vessel to which it is attached.
In witness whereof, I, the said George Alfred Lewis, have hereunto set
my hand and seal, this Twenty-eighth day of February, in the year
of our Lord One thousand eight hundred and fifty-seven.
GEORGE ALFRED (L.s.) LEWIS.