APPARATUS FOR RAISING AND LOWERING BOATS
Year: 1884

page_text: I, JOHN DONALDSON, of Church Wharf, Chiswick in the County of Middlesex,
(a member of the firm of John I. Thornycroft and Co) Steam Yacht and Launch
Builder do hereby declare the nature of said invention for "APPARATUS FOR
RAISING AND LOWERING BOATS" to be as follows:-
According to this invention for the purpose of raising and lowering boats
I provide two or more beams or davits having racks or teeth arranged in the
form of circular arc's these beams or davits being connected together by suitable
bars rods or ties.
The beams or davits are carried by arms able to turn on a pivot or centre or
pivots or centres coincident with the centre of the circular are represented by the
racks or series of teeth. Each beam or davit is formed or provided with a circular
rach or teeth as described and these are in gear with a spur wheel or pinion one
to each rack. These Spur wheels or pinions are connected so as to co-act in such
a way as to move the beams or davits simultaneously about their centre or pivot
or centres or pivots. A casing or casings is or are provided to receive the beams
or davits when their inner ends are lowered.
The lowering ropes or chains are worked from a barrel or drum which may or
not be on the same axis as the spur wheels or pinions and pass under pulleys
having their axes coincident with those on which turn the arms carrying the
beams or davits, thence the ropes or chains follow a direction parallel with the
said arms and are passed over guide pulleys or rollers pivotted in or on the beans
or davits, or the arrangement may be modified by causing the ropes or chains to
pass over guide pulleys in some other way to the barrel or drum. There may be
a barrel or drum to each lowering rope or chain,

page_text: I, JOHN DONALDSON, of Church Wharf, Chiswick, in the County of Middlesex
(a member of the firm of John I. Thornycroft and Co) Steam Yacht and Launch
Builders, do hereby declare the nature of my invention for "APPARATUS FOR
RAISING AND LOWERING BOATS," and in what manner the same is to be
performed, to be particularly described, and ascertained in and by the following
statement:—
According to this invention for the purpose of raising and lowering boats
I provide two or more beanis or davits having racks or teeth arranged in the
form of circular arcs these beams or davits being connected by suitable bars rods
.or ties.
The beams or davits are carried by arms able to turn on a pivot or centre or
pivots or centres coincident with the centre of the circular are represented by
the racks or series of teeth with which each beam or davit is fitted or provided
as described, and which racks are in gear with spur wheels or pinions one to each
rack. These spur wheels or pinions are connected so as to co-act in such a way as
to nove the beams or davits simultaneously about their centre or pivot or centres
or pivots. A casing or chamber or casings or chambers is or are provided to
receive the beams or davits when their inner ends are lowered.
The lowering ropes or chains are worked from a barrel or drum which may or
not be on the same axis as the spur wheels or pinions and pass under pulleys
having their axes either coincident or not with those on which turn the arms
carrying the beams or davits, thence the ropes or chains follow a direction parallel
with the said arins and are pas-ed over guide pulleys or rollers pivotted in or on
the beams or davits, or the arrangement may be inodified by causing the ropes
or chains to pass over guide pulleys in some other way to the barrel or drum.
There may be a barrel or drum to each lowering rope or chain.
Referring to the accompanying drawings Fig. 1 illustrates in plan the applica-
tion of my invention to a vessel of which only part is shown. Fig. 2 is a partial
transverse section of the vessel shewing apparatus according to my invention
arranged at its respective sides. Fig. 3 shews in side elevation part of the upper
portion of the vessel with my apparatus applied thereto. Fig.
shews partially
in section certain parts of the apparatus to an enlarged scale.
illustrating a modified arrangement of the apparatus.
Fig. 5 is a plan
Referring to Figs. 1 to 4, a, a åre beams or davits each carried by an arm b
centred at c. The beams or davits are arranged in pairs at each side of the vessel
and are connected by rods, bars or ties d. e, e are circular racks or series of teeth
of which there is one formed with or attached to each beam or davit a. Into each
rack or series of teeth e gears a spur wheel or pinion f formed or provided with a
sleeve g, with portions g that serve as rollers to keep the wheel in gear with the
rack. The sleeves of the two wheels turn in bearings in standards and are
traversed by a common driving shaft h but are able to turn independently thereof
except as hereinafter mentioned. The rollers 7' are arranged to roll on the plain

page_text: portions or flanges a¹ of the beam or davit a at each side of the rack or teeth c
and thus serve in conjunction with rollers j, carried by the standards i, and which
are in contact with the opposite sides of the flanges a¹ to cause the beams or davits
to move steadily when being actuated by their wheels or pinions f. k, k are
barrels or drums secured to the driving shaft h; from them the lowering ropes or
chains, are worked. These ropes or chains 1, pass under pulleys m, m whose
axes are in the example shown nearly coincident with those about which the arms b
turn, thence over pulleya m² m² to the pulley blocks n. o, o are clutches on the
shaft by means of which the sleeves g may be thrown in and out of gear with
the said shaft by operating clutch levers p, p. These levers are pivotted to the
standards i and are actuated by a hand lever q, shaft q', and connecting rods q².
is a worm wheel fast on the shaft h and driven by a worm on the shaft 8 which
is so arranged that it may be thrown in or out of gear with the driving shaft of
an engine t by means of a clutch t¹. As shown the engine t is centrally arranged
and serves to actuate two pairs of beams or davits, one pair arranged at each side
of the vessel u (Fig. 1). represents by way of example a .boat or vessel to be
raised or lowered, as for instance, a torpedo boat. y, y are casings or chambers
to receive the beams or davits when lowered inboard as shown at the left hand
side of Fig. 2. w, w are locking pins or bars for securing the beams or davits
either in their outward position, as shown at the right hand side of Fig. 2, or in
For this
their inward position as shown at the left hand side of the same figure.
purpose the locking pins or bars are arranged to slide in bearings in the standards i
and to take into suitably shaped openings w* formed in the beams or davits at the
required parts. To prevent the sleeves g being disconnected from the shaft h
before the beams or davits are otherwise held in place the locking pins or bars are
each formed with a slotted opening through which one of the levers ? passes.
With this arrangement as will be seen it is impossible to disconnect the sleeves g
from the shaft h by the hand lever q, shaft q', connecting rods q², and levers p
until the locking pins or bars w have entered the openings w* in the beams or
davits. Ropes or chains, one only of which can be seen in Fig. 2, may be employed
to prevent a boat when swinging from damaging the apparatus. One end of each
rope or chain is secured to the outer end portion of one of the beams or davits
whilst its other end is secured to the corresponding arm b.
The operation of the apparatus is as follows:-
Supposing a boat that is to be lowered, to be in the position shown at the left
hand side of Fig. 2, the engine t is started, and the shaft 8 being connected with
the engine shaft by operating the clutch t¹, the barrels or drums are sot in motion
and caused to slightly raise the boat from its support. The engine is then reversed
and the sleeves g are connected to the shaft by operating the levers p; the
locking pins or bars w are then withdrawn from the beams or davits thus allowing
the wheels or pinions f to rotate and move the beams or davits into the position
shown at the right hand side of Fig. 3. The sleeves g are then disconnected from
the shaft h the locking pins or bolts being simultaneously inserted into the beams
or davits which are thus secured in position whilst the lowering of the boat is
continued by the rotation of the barrels or drums k until it is waterborne. The
operation of raising will be readily understood from the foregoing description.
In the modified arrangement illustrated by Fig. 5 which is a diagrammatic view
the whoels or pinions f and the barrels or drums are mounted on separate
shafts h h respectively. These shafts h, h' carry worm wheels r, r' which are in
gear with worms on the shafts 8, 8¹. These shafts 8, 8¹ carry toothed wheels 8³, 8*
to which motion is imparted in turn from the engine t by a toothed wheel **
capable of sliding along but rotating with the engine shaft t. With this arrange-
ment of apparatus (whose operation will be readily understood without further
explanation) the operations of rotating the beams or davits from their inner to
their outer positions or vice versa and of winding up or unwinding the lowering
ropes or chains for raising and lowering a boat can be performed independently
and at separate times.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In apparatus for raising and lowering boats the use of beams or davits pro-
vided with racks or series of teeth having the form of circular arcs such beams or
davits being carried by arms (b) able to turn about the centres (c) of such ares
when suitably operated substantially in the manner and for the purposes herein-
above described and set forth.
2. Apparatus for raising and lowering boats constructed arranged and operating
substantially as hereinbefore described with reference to and illustrated in Figs. 1
to 4 inclusive of the drawings annexed or modified as described with reference to
and illustrated in Fig. 5.