A New or Improved Apparatus for Slewing Davits and the like.
Year: 1895

page_text: Date of Application, 8th Mar., 1895-Accepted, 18th May, 1895
COMPLETE SPECIFICATION.
A New or Improved Apparatus for Slewing Davits and the like.
We, GEORGE THOMAS DOVE of 12 Church Street, Shipwright, and FREDERICK
WILLIAM LEWIS, of 9 Howards Road, Balaam Street, Engineer, both in Plaistow,
in the County of Essex, 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:-
This invention relates to davits, anchor cranes and the like, such as are used on
ships for the purpose of moving boats or anchors or dismounting guns etc.; and
consists in new or improved apparatus for slewing or rotating such davits or anchor
cranes on their pivots, or shanks.
66
Our improvements may be applied to any kind of davits, but we describe them
as applied to a davit of the ordinary type, in which by reason of its shank resting
in a footstep, and being retained in position by an upper eye attached to the side
or rail of the ship it is free to swing, or slew "inboard or outboard." The
swinging or slewing operation is at the present time generally effected by means
of a number of men hauling on guys" attached to the davits, and is a cumbrous
and tedious operation even under the most favourable circumstances. When in
addition the difficulties are increased, by the rolling of a ship, causing the deck to
incline considerably, it becomes almost impossible to rapidly and efficiently handle
the boats. In fact it may safely be asserted that thousands of lives might easily have
been saved had a more efficient means been available (at the critical moment) for
quickly slewing the davits "outboard" and thereby enabling the boat to be
lowered on to the water.
Now in this invention we provide apparatus by means of which one man at each
davit can easily, conveniently, and quickly move a boat "outboard" preparatory
to dropping it into the water, and in order to effect this we rigidly attach to the
shank of each of the davits a spur, bevel, or worm wheel, into which gears either a
pinion, wheel, or worm in such manner that when the spindle of either of the
latter is rotated by manual or other power, the davits are slewed or swung so as to
move the boat either "inboard" or "
"
outboard as may be desired.
In the accompanying drawings a worm and worm wheel are shewn, but spur or
bevel wheels may be substituted, and in either case a long spindle may be used
so that the men operating them may stand in the most convenient positions, in
some cases at a distance from the davits.
Fig. 1 is an elevation of a davit of ordinary pattern, wheels, spindles, and a
worm.
Fig. 2 is a plan, and
Fig. 3 is an elevation of mechanism for slewing a davit according to our
invention.
Fig. 4 is a plan of a modification.
Fig. 5 is a diagram of the three positions of a boat, during slewing.
Fig. 6 is a view of a ratchet lever.
Fig. 7 is a view of a handle for fitting to same.
A designates the ships side or rail, and B a hammock berthing thereon. C is the
davit, the shank c of which passes through an upper eye D and its lower end c' fits

page_text: into and rests upon a footstep bearing E; and D and E being both attached firmly
to the side of the ship support the davit and dependent boat.
In Fig. 1a wheel G' is fixed to the davit and gears with a pinion G' which is
fixed upon a spindle G³. The other end of this spindle has a worm wheel G fixed
upon it, which engages with a worm H. The men operating this can thus stand at
any convenient distance from the davits.
In Figs. 2, 3, 4, the worm wheel G is fixed to the shank of the davit at any
convenient height. and carries it round with it. Gearing into the worm wheel G
is a worm H, which is fixed to and rotates with a spindle h, and this spindle
working in bearings i in a frame I which is rigidly attached to the deck, hammock
berthing, or other part of the ship it is obvious that the rotation of the spindle h
and worm H will result in the slewing of the davit shank c and davit.
A square is formed at one or both ends of the spindle h, and upon this square
fits a handle or crank which may be turned by a man; or a wheel may be fitted
to it and be operated by any convenient' source of power.
Fig. 4 shews an apparatus according to our invention in which additional power
is gained by extending the frame I and forming additional bearings upon it, in
which revolves an additional spindle 2 (with square ³) upon which is fixed a spur
pinion K which gears with a larger wheel L fixed upon the spindle h. By this
means two men, one working the crank of each spindle can move even the heaviest
boats or anchors; and in cases where one pair of wheels such as K and L are
insufficient for this purpose, a third or even a fourth spindle and pair of wheels
may be used; k is a pin which fits in either of two grooves k¹ and k² in the
spindle to retain it in either of two positions.
"
"
Fig. 5 shews diagrammatically, the three positions which a boat assumes during
the slewing of the davits in such manner as to move it from an "inboard to an
"outboard" position preparatory to lowering it into the sea. The "inboard or
normal stowed position is shewn in full lines, the intermediate position in dotted
lines, and the outboard" position in chain dotted lines.
The operation is as follows:-The boat is first lifted clear of the deck and then
the bow davit is slewed from 1 to 2, which brings the bow of the boat outside the
bow davit, as shewn in the dotted position. While this is being done the stern
davit is slewed first from 1 to 2, and then back to 3. Then the stern davit is
slewed from 3 to 4, and at the same time the bow davit moves first from 2 to 3
and then back to 4. When both davits are in the position marked 4 the boat is
"outboard" as shewn in chain-dotted lines, and can be lowered directly on to the
water. When the boat is to be moved from the "outboard to the "inboard "
position, the converse of the preceding order of operation takes place. The gear
can be made either right or left handed so that in putting a boat out or
the men can face each other.
"
" vice versa
"
Fig. 6 shews a ratchet lever suitable for applying to one of the squares h¹ or h³
where there is insufficient room for applying an ordinary crank. By forming the
bandle of this with a pin o and socket of the socket can be removed and a handle
as shewn in Fig. 7 applied to the pin o¹.. In either case they are fixed by a split
key o² or other suitable means, and can be made to operate either in a "fore and
aft," athwartship, or any other direction.
We in general arrange the frame carrying the mechanism in such manner that
their worms or wheels may be easily and readily thrown out of gear, or removed
from contact with the worm wheel G, and by so removing it the davits may be
operated in the ordinary manner. Any convenient and suitable mechanism may be
used for this purpose, such as screws, cotters, or their equivalents.
This system of operating boats davits can be equally well applied to anchor
davits or cranes, and the gearing used prevents the davit swaying about in bad
weather, thus providing against injury to boats from their dashing against the davits.
In some cases we fit a locking pin or plate, so that the gear can be fixed in any
position.

page_text: 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 :-
1. The improved method of slewing ships davits, anchor cranes and the like, by
means of gearing, substantially as described and shewn.
2. The improved apparatus for slewing ships davits, anchor cranes and the like,
consisting essentially of a worm or other gear wheel fixed to the shank of the davit,
and a worm or wheel engaging therewith, and moving the davit as required.
3. In an apparatus for slewing ships davits, anchor cranes and the like, the
combination of a worm or other geared wheel fixed to the davit, a worm or wheel
engaging therewith, and rotating with a spindle, a frame with bearings for said
spindle fixed to some part of the ship, and a crank handle or ratchet lever for
operating the same, substantially as described and shewn.
4. In an apparatus for slewing ships davits, anchor cranes and the like, the
combination of the worm or gear wheel G, the worm H, the spindle h, the frame 1,
and a handle or crank, substantially as described and shewn.
5. In an apparatus for slewing ships davits, anchor cranes and the like, the
combination of the worm or gear wheel G, the worm H, the spindle, the frame I
the spindle, the wheels K and L, and a handle or crank, substantially as
described and shewn.
6. For operating the hereinbefore described apparatus, the ratchet lever and
handle substantially as described and shewn with reference to Figs. 6 and 7.
Dated this 8th day of March 1895.
WILLIAM J. MUNDEN,
106, Priory Park Road, Kilburn, Agent for the Applicants.