Im- PROVEMENTS IN APPARATUS FOR DRAWING SHIPS OUT OF WATER
Year: 1853

page_text: LETTERS PATENT to William Melville, of Burntisland, in the
County of Fife, North Britain, Tailor, for the Invention of "Im-
PROVEMENTS IN APPARATUS FOR DRAWING SHIPS OUT OF WATER."-
A communication.
Scaled the 7th April 1854, and dated the 20th October 1858.
PROVISIONAL SPECIFICATION left by the said William Melville..
at the Office of the Commissioners of Patents, with his Petition,
on the 20th October 1858.
I, WILLIAM MELVILLE, of Burntisland, in the County of Fife, North
Britain, Tailor, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN APPARATUS FOR DRAWING SHIPS OUT OF WATER," com-
municated to me from abroad, to be as follows:-
This Invention relates to the arrangement and construction of a screw
purchase or mechanical power for facilitating the withdrawal of ships
from the water on an inclined plane. The power for obtaining the
movement is conveniently attainable from a steam engine laid down by
the side of the slip or purchase way, a shaft from such prime mover
being fitted up with disconnecting gear and reverse motions, with gear-

page_text: ing for varying the rate of traverse of the vessel. The last shaft of the
series included in the gearing carries a spur pinion in gear with a spur
wheel fast on the extreme landward end of a horizontal screw spindle,
supported in suitable bearings in a direction parallel with the line of
the ship's traverse or the lengthway of the slip. This screw is of large
diameter, and is cut with a right and left hand thread, each thread
being separate and distinct, and cut from the end of the spindle to the
longitudinal centre thereof, where the two threads join, that is to say,
one half of the spindle is cut with a right-hand thread and the other
with a left-hand thread. Each screw thread is fitted with a deep nut
cross head capable of horizontal traverse in horizontal guides, and
carrying a pair of parallel tensional rods running down one on each
side of the screw, the pair of rods from one nut cross head being
arranged to work inside or between the pair on the other cross head.
The outside pair of rods are connected at their opposite or seaward end
by a plain cross tail, to which an engaging and disengaging catch is
attached for connection at pleasure with the line of hauling chain.
Similarly the two inner rods pass down parallel to the line of the
screw, and carry at their end a similar catch, also, for connection with
the hauling chain. The chain is formed of long flat bar links jointed
together by cross pins in any convenient manner like the chains of a
suspension bridge, and the two catches on the seaward ends of the
connecting rods passing from the screw spindle nuts are arranged so as
to be capable of catching upon pius or shoulders at each link or joint
in the line of chain. The hauling chain is connected to a carriage
in the usual way, and when a ship is to be hauled up, the screw
spindle is set in motion by its gearing at the required rate, so as to
cause 'one nut to traverse up and the other down the section of the
screw on which it is placed. In this way one nut acts so as to draw
up the ship's carriage, whilst the other nut traverses downwards in the
reverse direction for a fresh hold. At the termination of the traverse
of the two nuts one nut will be at the end of the screw spindle, and
the other will be at its centre. In this condition the screw's rotation
is reversed, and the two nuts are thus caused to traverse in precisely
opposite directions. The catch which has just acted in hauling up

page_text: the carriage is now 'disengaged, whilst the reverse catch engages a link
on the hauling chain, both movements being self-acting, a hook fitted
with an incline being used for the purpose. In this way, by merely
reversing the gearing's rotation at the proper intervals, the carriage
is hauled up with a continuous movement, as there is always one
hauling uut in action: As the chain is thus hauled inwards towards
the land each link is passed upon a polygonal drum or carrying barrel,
the side of the polygon being made to correspond in length with the
length of the individual links of the hauling, chain.. The chain as
carried up is thus wound upon. the carrying barrel; and in order that
it may be evenly and uniformly wound the barrel is set upon a hori-
zontal screw spindle, so that as it revolves by the winding-on pressure
of the chain the barrel has a lateral- traverse along its spindle. The
pitch of this screw being made to correspond with the pitch of the
wound up chain, the latter is thus evenly wound upon the barrel in a
single and regular layer. The actuating gearing also drives a short
shaft carrying a winding barrel, from which a-line may. be passed to
the carriage to haul-it by direct.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Melville in the Great Seal Patent Office
on the 20th April 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I;
WILLIAM MELVILLE, of Burntisland, in the County of Fife, North
Britain, Tailor, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of October, in the year
of our Lord One thousand eight hundred and fifty-three, in the seven-
teenth
year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Melville, Her special license
that I,. the said William Melville, my executors, administrators, and
assigns, or such others as I, the said William Melville, my executors,
administrators, or assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein

page_text: -
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 APPARATUS FOR
DRAWING SHIPS OUT OF WATER," being a communication from abroad,
upon the condition (amongst others) that I, the said William Melville,
by an instrument in writing under my hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the sanie 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 William Melville, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is
to say:
.
This Invention relates to the arrangement and construction of a
screw purchase or mechanical power for facilitating the withdrawal of
ships from the water on an inclined plane. The power for obtaining
the movement is conveniently attainable from a steam engine laid
down by the side of the slip or purchase way, a shaft from such prime
mover being fitted up with disconnecting gear and reverse motions
with gearing for varying the rate of traverse of the vessel. The last
shaft of the series included in the gearing carries a spur pinion in gear
with a spur wheel fast on the extreme landward end of a horizontal
screw spindle supported in suitable bearings in a direction parallel with
the line of the ship's traverse or the lengthway of the slip. This
screw is of large diameter, and is cut with a right and left hand thread
each thread being separate and distinct, and cut from the end of the
spindle to the longitudinal centre thereof, where the two threads join
that is to say, one half of the spindle is cut with a right-hand thread
and the other with a left-hand thread. Each screw thread is fitte
with a deep nut cross head capable of horizontal traverse in horizonta
guides, and carrying a pair of parallel tensional rods running down on
on each side of the screw, the pair of rods from one nut cross hea

page_text: being arranged to work inside or between the pair on the other cros
head. The two outside rods are connected at their opposite or seaward
end by a plain cross tail, to which an engaging and disengaging catel
is attached for connection at pleasure with the line of hauling chain
Similarly the two inner rods pass down parallel to the line of the screw
and carry at their end a similar catch, also for connection with the
hauling chain. The chain is formed of long flat bar links jointed
together by cross pins in any convenient manner, like the chains of a
suspension bridge, and the two catches on the seaward ends of the con-
necting rods passing from the screw spindle nuts are arranged so as to
be capable of catching upon pins or shoulders at each link or joint in
the line of chain. The hauling chain is connected to a carriage in the
usual way, and when a ship is to be hauled up, the screw spindle is set
in motion by its gearing at the required rate, so as to cause one nut to
traverse up and the other down the section of the screw on which it is
placed. In this way one nut acts so as to draw up the ship's carriage,
whilst the other nut traverses downwards in the reverse direction for a
fresh hold. At the termination of the traverse of the two nuts one nut
will be at the end of the screw spindle, and the other will be at its
centre. In this condition the screw's rotation is a reversed, and the two
nuts are thus caused to traverse in precisely opposite directions. The
catch which has just acted in hauling up the carriage is now disengaged,
whilst the reverse catch engages a link on the hauling chain, both move-
ments being self-acting, a hook fitted with an incline being used for the
purpose. In this way, by merely reversing the gearing's rotation at
the proper intervals, the carriage is hauled up with a continuous move-
ment, as there is always one hauling nut in action. As the chain is
hus hauled inwards towards the land each link is passed upon a poly-
ronal drum or carrying barrel, the side of the polygon being made to
correspond in length with the length of the individual links of the
auling chain. The chain as carried up is thus wound upon the
arrying barrel, and in order that it may be evenly and uniformly
round the barrel is set upon a horizontal screw spindle, so that as it
evolves by the winding-on pressure of the chain the barrel has a lateral-
averse along its spindle. The pitch of this screw being made to cor-

page_text: respond with the pitch of the wound up chain, the latter is thus evenly
wound upon the barrel in a single and regular layer. The actuating
gearing also drives a short shaft carrying a winding barrel, from which
a line may be passed to the carriage to haul it by direct.
•
.
And in order that the said Invention may be properly understood I
shall now proceed to describe the several Figures on the "Sheet of
Drawings hereunto attached. Figure 1, on the Sheet of Drawings is
a longitudinal section of a portion of a slip, showing the purchase in
side elevation complete. Figure 2, is a corresponding plan of the
purchase. A large compound or right and left threaded screw A, is
laid down at the head of the slip and carried in end bearings B, C;
set on a timber base forming the upper surface of a massive founda-
tion D. The outer or higher projecting end of this screw carries a
large spur wheel E, by which it is actuated through a train of
gearing in connection with the steam engine or other prime mover
of the establishment. Each thread of the screw, the junction of the
two ends being at the exact longitudinal centre of the spindle, carries
a massive nut F, G, both nuts being expanded laterally to such an
extent as to fit in between the longitudinal guide frame pieces H,
bolted down to the foundation, and to the end bearing pedestals of
the screw. The upper or right-hand nut G has attached to it a pair
of parallel traction rods I, running down on each side of the screw,
and at the same axial level. These rods work freely through eyes in
the left-hand nut F, as well as through similar holes in the bearing
B, and pass thence to the large duplex horse-shoe hook or link J, K,
to which they are jointed by link discs I. This arrangement forms one
of the hauling movenients for the ship carriage. The other is made
up of another pair of parallel traction rods M, which are connected to
the left-hand nut. F, passing thence through eyes in the pedestal B
outside the first pair and through pedestal guides N, bolted to the
timber base of the incline, and they terminate in a larger pedestal hook
O, P, to which they are jointed by disc links Q, as before. The hauling
chain R is formed of flat iron links in alternate sets of three and four
pieces, jointed by transverse pins, like the cliains of a suspension bridge
The lower end of this chain is connected in the usual way to the ship

page_text: square
carriage on the ship incline running down to the water at S, the upward
course of the chain being in the line of the main traction screw A, over
which it passes upon a line of supporting pulleys on a timber stage T
to the coiling drum U. The connection of the traversing nuts F, G, and
their duplex hooks J, O, with the hauling chain, is by means of
shoulders V, formed on the links at each joint eye, and contrived so
that the upper pieces J, O, of the traction hooks may fall over by their
own weight and catch upon the shoulders at each change, whilst the
corresponding lower pieces K, P, are borne up to a catch in a similar
way by blade springs underneath, each portion of the hooks being being
loosely jointed to the disc links L, Q. The whole of the movements are
driven by the first motion shaft W, in connection with the steam engine.
The spur wheel X on this shaft gears with a wheel Y, fast on a short
carrier shaft, having upon it a pinion Z, in gear with a large spur
wheel a. The wheel a, is fast on a longer shaft b, carrying as well three
wheels of regularly graduated diameters, gearing with three inverse
corresponding wheels on the shaft c. These wheels are capable of being
engaged in any given pairs, like the speed cones of a lathe, so that the
shaft c, can be driven at three different rates with a continuously regular
motion of the driving shaft. As represented in the Drawings, the
slowest motion is in gear, the least wheel of the driving series on the
shaft b, being in gear with the largest one on the opposite shaft c.
This latter shaft also carries a spur pinion d, driving the large wheel E
on the right and left screw spindle, and its prolonged end also carries
a bevil pinion e, in gear with the bevil wheel f, fast on the spindle of
the capstan or windlass barrel g, for a simple hauling motion. The
driving gearing, which of course may be variously arranged to suit actual
localities, is also furnished with reversing gear, such as an open and
cross belt movement, for the purpose of driving the screw in alternate
directions. The action of the purchase is this:-The ship being upon
the carriage, one of the drag hooks of the traversing nuts is passed upon
one of the angular shoulders of the traction chain, just as both hooks
are represented in our Drawings. The gearing is then put in motion to
drive the screw, and the obvious result of the screw's rotation is, that
one of the nuts F, G, is made to traverse along its guides H, towards

page_text: the central junction of the right and left threads, whilst the othe
traverses in the opposite direction, so as to approach one end of the
spindle. In the position here selected for illustrated the two nuts are
shewn at the extreme ends of the spindle, the nut G having traversed
to the landward extremity of the screw, whilst the nut F has similarly
reached the other or seaward end. The screw's movement is, therefore
to be reversed at this stage, causing the two nuts to approach each
other, the hook O becoming the hauler, whilst the other one J slides
freely back over the smooth edge of the chain. The traverse of ench
nut is made to correspond exactly with the length of the individual
chain links, so that as the screw is continuously driven in alternate
directions each hook alternately catches and slips in its operation upon
the chain, and the carriage with the ship upon it is thus steadily and
continuously drawn up the incline. The hauling chain is always
preserved in its complete unbroken condition, and as a convenient
means of stowing the hauled up length it is wound upon the hexagonal
drum U. Each of the sides of this drum corresponds exactly with
the length of the chain links, so that in winding up the bend can
always take place with facility from the joints hitting the angles as
they come round. The pair of inclined standards h, carry this drum by
means of the horizontal screw shaft i, the ends of which j, are squared
to fit immoveably in square recesses on the tops of the standards.
The boss of the drum is formed as a nut to fit the screwed shaft, the
pitch of the threads of which is made to agree with the space required
for the chain coils. In this way when the hauling commences the
drum is always stationed near one end of its spindle, and as the loose
end of the chain comes forward it passes upon the drum, causing the
latter to turn as each link is laid on. This revolution of the drum then
causes its lateral traverse along the screw, so that the chain coils are
thus wound up spirally without interfering with each other. As the
carriage is lowered to the water the reverse movement takes place, and
the chain winds off, cach link being supported in turn as it goes down
by the traction hooks alternately, just as in the upward traverse.
will be obvious to the practical man that the details of this Invention
may be variously modified. For example, the right and left threaded
It

page_text: 5
crews may be detached or separate, each thread being cut or formed
on a separate spindle, the two spindles being driven in any convenient
nanner by gearing suitably arranged for such a contrivance. Or, if
two separate screw spindles are employed, the threads of both may be
either right or left, that is, both may be the same, the necessary action
being obtained by driving the two spindles in reverse directions; such
separate screw spindles may either be laid down with their axes in the
same or one straight line or parallel to each other.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I may observe, in conclusion, that I do not confine
or restrict myself to the precise details or arrangements which I have
had occasion to describe or refer to, as many variations may be made
therefrom without deviating from the principles or main features of the
said Invention; but what I consider to be novel and original, and there-
fore claim as the Invention secured to me by the herein-before in part
recited Letters Patent, is,-
First, the general arrangement and construction of machinery, appa-
ratus, or means to be used for drawing ships out of water, as herein-
before described.
Second, the system or mode of drawing ships out of water by means
of a right and left threaded screw spindle or spindles, made to rotate in
alternate reverse directions, for the production of a continuous or nearly
continuous tractive action.
Third, the system or mode of drawing ships out of water by means
of separate similarly threaded screws made to rotate in alternate reversc
directions in concert with each other.
Fourth, the application and use in screw purchases of alternately
engaging and disengaging catches for the purpose of securing con-
0 tinuous or nearly continuous traction from the alternate reverse rotations
of the screw or screws.
35
Fifth, the system or mode of coiling up or receiving the tractive
chains or hauling links by means of drums or rotatory holders with
polygonal or angular peripheries.
Sixth, the application and use of drums or coiling holders fo

page_text: receiving the hauling chains, wherein the length of the right line
sides, is equal to that of the hauling links, or a determined number
of the same.
Seventh, the system or mode of coiling up or receiving the hauling
chains
or links by means of drums or rotatory holders capable of end or
lateral traverse to suit the pitch of the coils.
Eighth, the application and use of screw shafts or holders for giving
end or lateral traverse to the winding drunis.
In witness whereof, I, the said William Melville, have here-
unto set my hand and seal, this Eighteenth day of April, in 1
the year of our Lord One thousand eight hundred and fifty-
four.
WILLIAM MELVILLE. (L.S.)