IMPROVEMENTS IN APPARATUS FOR RAISING AND LOWERING SHIPS' BOATS
Year: 1876

page_text: LETTERS PATENT to Thomas Matthew Gisborne, of Blackheath, in the County
of Kent, for the Invention of "IMPROVEMENTS IN APPARATUS FOR RAISING
AND LOWERING SHIPS' BOATS."
Sealed the 1st September 1876, and dated the 8th April 1876.
PROVISIONAL SPECIFICATION left by the said Thomas Matthew Gisborne
at the Office of the Commissioners of Patents on the 8th April 1876.
THOMAS MATTHEW GISBORNE, of Blackheath, in the County of Kent.
MENTS IN APPARATUS FOR RAISING AND LOWERING SHIPS' BOATS."
"1
IMPROVE-
According to my Invention I mount on the ships' davits, at the points where the
blocks and falls are ordinarily suspended, an axle, so connected thereto by swivelling
bearings or equivalent devices that the davits shall be free to slew or swing round
in the ordinary manner. Upon this axle I fix a wheel or drum, round which is
coiled or passed a rope, by pulling which the wheel and axle are made to revolve.
To the axle are attached the ends of ropes or chains, from which the boat is sus-
pended, so that by the rotation of the axle as aforesaid the ropes or chains are
wound upon or unwound from the same, and thus the raising or lowering of the
boat is effected. The rotation of the wheel or drum may be effected either by
hauling at the end of a rope that is coiled upon the wheel, or by imparting motion
to an endless rope or chain that passes round a grooved or pitch wheel.
To obtain greater power for raising the boat the ropes or chains from which it
is suspended inay be attached at one end to the axle as described, and at the other
end to a point on the davits, or in any other manner, whereby they are prevented
from being wound up by the rotation of the axle, and the boat is suspended from
a block or sheave hung upon the rope. Or I employ for this purpose the arrange-
ment known as the "differential wheel and axle," wherein while the one end of
the rope is being wound upon the wheel or enlarged part of the axle, the other end
is at the same time unwound from a part of the axle of smaller diameter.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Matthew Gisborne in the Great Seal Patent Office on the
7th October 1876.
THOMAS MATTHEW GISBORNE, of Blackheath, in the County of Kent. IMPROVE
MENTS IN APPARATUS FOR RAISING AND LOWERING SHIPS' BOATS."
According to my Invention I mount on the ships' davits, at the points where
the blocks and falls are ordinarily suspended, an axle, so connected thereto by
swivelling bearings or equivalent devices that the davits shall be free to slew or
swing round in the ordinary manner. Upon this axle I fix a wheel or drumm round
which is coiled or passed a rope, by pulling which the wheel and axle are made to
revolve. To the axle are attached the ends of ropes or chains from which the boat
is suspended, so that by the rotation of the axle as aforesaid the ropes or chains
are wound upon or unwound from the same, and thus the raising or lowering of
the boat is effected. The rotation of the wheel or drum may be effected either by
hauling at the end of a rope that is coiled upon the wheel, or by imparting motion
to an endless rope or chain that passes round a grooved or pitch wheel.
To obtain greater power for raising the boat the ropes or chains from which it is
suspended may be attached at one end to the axle as described, and at the other
end to a point on the davits, or in any other manner, whereby they are prevented
from being wound up by the rotation of the axle, and the boat is suspended from
a block or sheave hung upon the rope. Or I employ for this purpose the arrange-
ment known as the "differential wheel and axle," wherein while the one end of the
rope is being wound upon the wheel or enlarged part of the axle the other end is
at the same time unwound from a part of the axle of smaller diameter.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 shews a front elevation of my before-described boat raising and lowering
apparatus; Fig. 2 is an end view; Fig. 3 is a plan with the boat and davits swung
into the outward position; and Fig. 4 is a plan shewing the parts in the act of
being slewed or swung round into the inward or outward position.
The davits A, A, which are of usual construction, that is, arranged to swing
round in their sockets, carry at their ends eyes B, B, fitting with vertical pins
loosely in holes in the davits, so that the eyes can turn or swivel therein. The
eyes B, B, serve as bearings to a shaft or axle C, upon which is fixed a pitch
wheel D, having an endless chain E passed round it so that by hauling the chain
the wheel and axle can be rotated. One end of each rope or chain "fall" G, G,
by which the boat is raised or lowered, is fastened to the axle by a collar and set
screw F, or by any other means which will cause the "fall" to coil round the axle
when the axle is made to rotate, and the other end of each fall is either fastened
to the boat or to some point of the davits or elsewhere so as not to be coiled round
the axle when it revolves. In this latter case its connection with the boat I is
made by means of a pulley block or ring, through which the loop of the fall passes,
and it is obvious this arrangement much increases the elevating power of any
given arrangement of the wheel and axle fixed as above described; and it is also
obvious that the number of blocks or sheaves fixed, as shewn at H and at H¹, may
be multiplied with a corresponding increase of power. From this arrangement
it will be seen that, assuming the boat to be in the lowered position, then by
rotating the wheel and axle by means of the chain E the "falls" G, G, will be coiled
up on the axle, thereby raising the boat to the dotted position shewn in Fig. 1,
whereupon the boat can be brought inboard by slewing the davits in the usual
way, as shewn at Fig. 4, the eyes turning in the sockets on the davits to allow of
this. In order to insure that the two falls G, G, are equally wound or unwound
by the revolution of the axle, the latter may have reversed screw threads formed
upon it, as shewn; and K, K, are collars which run along the screw, and act as
guides to the falls.
The wheel D is, by preference, arranged to revolve in an

page_text: apparatus, one form of which is shewn at D', made with suitable framing and
guides for preventing the rope or chain E from running off the wheel D, and
which apparatus D₁ hangs free on the axle C, so that it can accommodate itself to
the position of E. Instead of the pitch wheel and endless chain might be used a
double drum, on one part of which one end of the rope or chain E is wound in one
direction, while the other end is wound in the contrary direction on the other part,
so that when the drum and axle revolve as much of the chain or rope E as is
unwound off one part of the drum is wound upon the other part; or a single drum
may be used, to which only one end of E is fixed, a sufficient quantity being wound
round the drum to clevate the boat when the free end is hauled upon, and the boat
is allowed to descend by its own weight. Also, as before mentioned, the boat may
be raised without the intervention of any blocks by simply attaching the one end
of the "fall" G to the axle, and the other end to the releasing tackle of the boat;
or the axle may be formed with the one part thereof of a larger diameter than
the other part, one end of each fall being fastened to the axle where the diameter
is greater, and the other end where it is less, and the boat is suspended from a
sheave or block running on the loop of each fall, such contrivance being well
known as the "differential wheel and axle." The eyes B which carry the axle
may be arranged to be shifted from the position above the davits, as shewn, to the
reverse position below them, as may be most convenient, and to afford greater
range of adjustment of the height of the axle the eye may be formed at the end of
the stem, projecting some height above or below the davit, and on this stem may
be formed one or more additional eyes, into which the axle may be fitted.
instead of arranging the eyes B to swivel in holes in the davits they may be
suspended therefrom by links of a length of chain having a sufficient amount of
flexibility to allow of the davits being slewed or swung round as described.
'
Also
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I wish it to be understood that I do not claim generally
the use of a wheel and axle carried by the ships' davits for raising and lowering
ships' boats, but I claim in respect of such apparatus-
First. Supporting the revolving axle by which the boat is raised or lowered by
means of bearings swivelling in or otherwise connected to the davits in such manner
that the davits can be slewed or swung round in the ordinary mauner, substantially
as herein described.
Second. Suspending the boat by one or more blocks or pullies from a loop of each
fall, one end of which is attached to and wound upon the axle, while the other end
is connected to a point on the davit, or in any other manner, whereby it is prevented
from being wound up, substantially as herein described.
In witness whereof, I, the said Thomas Matthew Gisborne, have hereunto set
iny hand and seal, this Fifth day of October, in the year of our Lord
One thousand eight hundred and seventy-six.
THOMAS M. GISBORNE. (L.S.)