A New or Improved Lifting Dock, or Means for Bodily Raising and Lowering Ships or other Heavy Bodies, and Apparatus or Appliances in connection therewith.
Year: 1893

page_text: Date of Application, 3rd Oct., 1893-Accepted, 20th Jan., 1894
COMPLETE SPECIFICATION.
A New or Improved Lifting Dock, or Means for Bodily Raising
and Lowering Ships or other Heavy Bodies, and Apparatus
or Appliances in connection therewith.
I, Jabez Pratt BROOKS of 82 Tollington Park, London, N., Gentleman, do
hereby declare the nature of this invention (a communication to me from abroad
from Luis Wirtz of Vigo, Spain) 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 a new or improved lifting dock or means for bodily
lifting or raising (and lowering) ships such as steamships, sailing ships or other
heavy bodies and to various appliances and apparatus in connection therewith the
object of this invention being to provide a "lifting dock" or means to "dry
dock a vessel without the necessity of a graving dock as heretofore and for
other lifting or lowering purposes and this novel "dock' can moreover be
constructed and used in many places (such as where sandy bottoms exist) where
it would be impossible or difficult to build ordinary dry docks or graving docks.
The main and novel features of this invention are:-—
1. The system of construction and foundation upon any suitable support such as
masonry but advantageously upon piles bearing upon ordinary earth screws or
screw piles or the like or upon screws of the character known as " Mitchell's
screws (for the sake of brevity I shall hereinafter refer to all such screws as
"Mitchell's screws") such as are applied to or in connection with various structures
in or under water.
2. To the special construction of these Mitchell screws in a double form for the
purpose of this invention.
3. The injection of hydraulic cement (through these piles and screws) into the
sand in order to increase the bearing power and stability of the same in sandy soil
or the like the said piles and screws being also at the same time thus filled with
cement.
4. The supports (which bear the weight of the lifting bed and load thereon)
and which can be driven (ie. rotated) from the fixed landing above and are
arranged and mounted at any desired height above the water level and for the sake
of brevity I shall hereinafter refer to these supports as the "female" screw each
of which is marked G in the accompanying drawings.
5. The shape and arrangement of the thread of the depending pillars or hangers
by means of which the lifting bed is suspended from said supports and raised or
lowered and for the sake of brevity I shall hereinafter refer to each of these
depending pillars or hangers as the "male" screw each of which is marked R in
the accompanying drawings.
"
6. The arrangement by which the balls will continually adjust themselves as they
female
wear away so as to ensure the necessary contact between the "male" and "
screw and the means to withdraw and re-insert said balls and keep same clean.
7. Means to clear the thread of the screws of deposits and scrape same pre-
paratory to cleaning it.
8. The cleaning arrangements by means of which the thread of the male screws
are cleaned-advantageously with the assistance of an acid-preparatory to coating
as follows.
9. The zinc or other coating arrangement hereinafter described by means of
which the thread of the male screw is coated with zinc or any other suitable coating
material (non oxydising in water).

page_text: 10. Means for guiding the lifting bed as it travels up and down,
11. Means for neutralising or counteracting the effect of the waves (if any)
upon the lifting bed and its load.
12. Means to prevent the aforesaid male screws from revolving.
13. To various other details and contrivances all of which will be more fully
described and referred to hereinafter and finally pointed out in the claims.
The following are some of the advantages obtained by this invention.
1. It can be located in various positions and depths of water, and in great depths
of water it is more economical to construct than stone dry docks or so-called
graving docks and is adapted to be located to suit in different cases the best
conditions available for access of vessels thereto.
2. It is adapted to all kinds of sandy soils, sea beaches, river shores etc. (as well
as to solid foundations of stone or rock) or for any other suitable positions.
3. It dispenses with the costly foundations of stone dry docks and does not
require the long time usually required for the construction of same-as this lifting
dock can be constructed in a very short time.
4. It is economical in construction and maintenance.
5. It is especially adapted for use in connection with ship building yards,
arsenals etc. that have at their disposal a certain amount of motive power as
this dock can be driven when required by the ordinary engine of the works or by
any other suitable means.
6. It is especially adapted to be built in sections and may be enlarged if it
should be so required.
7. It can be transported easily by land or sea as none of its parts are
necessarily of unwieldy size or weight.
-
8. Many of the parts are interchangeable so that such parts or pieces can be
kept in store for ready replacement and can be utilized for different sizes of
docks and this duplication of parts has the further advantage of cheapening the
cost of production of many of such parts.
9. It can if desired be shifted from one position to another at comparatively
moderate cost.
10. It can be adapted for the smaller sizes of vessels such as tugs, barges, or for
other vessels as desired.
11. The main frame work or lifting bed can be utilized as a raising and lowering
landing stage or pier if its position be suitable.
12. Also it can be used to raise or lower other heavy bodies or weights from one
position to another.
Having described in the preceding paragraphs the general arrangement and
advantages of this lifting dock I will now enter into the details of the different
working parts and the arrangement and construction of same and appliances in
connection therewith and fully describe same with reference to the drawings
hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a plan of one side of the lifting dock showing the mechanism for
raising and lowering the "lifting bed " B from above according to this invention.
Fig. 2 is a side elevation looking in the direction of the arrow 1 Fig. 1.
Fig. 3 is an edge view (partly in section) of one end of the lifting dock-and
part end view of the "lifting bed " and vessel thereon.
.
Fig. 4 is a local view in elevation showing a modification of the supporting
structure hereinafter explained.
Fig. 4 is a plan of Fig. 4.
Fig. 5 is a further modification of the supporting structure and
Fig. 5 a plan thereof also hereinafter explained.
Fig. 6 shows the application of vertical guide rails fixed to the dock wall, with
grooved wheels on the lifting bed B running upon said guide rails.
Fig. 6ª is a plan of Fig. 6.

page_text: Fig. 7 shows similar guide rails on a frame work or special support and grooved
wheels on the lifting bed B and
Fig. 7 is a plan of Fig. 7.
Fig. 8 is a local vertical sectional view on a much enlarged scale of the upper
part of Fig. 9.
Fig. 9 is a local view in sectional elevation of the device termed the female
screw and pulley thereon by which same is revolved upon the screw lifting
pillar R (ie. the male screw) and showing other details in connection herewith.
Fig. 10 is a "local" plan view on an enlarged scale on the line 2-2 Fig. 8
showing the means for withdrawing the ball bearings from between the male and
fomale screws.
Fig. 12 is a "local" vertical sectional view of the fixed bed plate or bearing H
upon which the female screw is borne and revolves and upon which bed plate H
the load borne by G is received-and showing the conical roller bearings between
the latter (G) and the former (H).
Fig. 13 shows special construction of self-entering piles or Mitchell serews
hereinafter fully explained.
Fig. 14 is a diagrammatic view showing arrangement to assist in preventing
rotation of the male screw R.
Fig. 15 is a diagrammatic view (in plan) showing a means of transmitting the
motive power from the main driving shaft to the several driving pulleys O.
Figs. 16 to 22 are "local" sectional views in elevation (except Fig. 17 in plan)
showing the contrivance for scraping and cleaning the male screw R and coating
same with molten zinc etc. and. contrivance for pressing such zinc coating
firmly on to the said male screw all of which figures are hereinafter separately
referred to.
Similar letters of reference indicate corresponding parts throughout.
THE SUPPORTING STRUCTURE.
The construction of the piles P or supports of the bed plate H can be in itself
adapted to the circumstances of each case. Should the bottom on which the dock
is erected be sandy an economical and convenient structure would be formed by
hollow or solid cylindrical piles fitted with ordinary Mitchell's screws driven into
the ground in the usual way. In this case each one of the male screws R might
be supported by a group of three piles P placed at each apex of an equilateral
triangle as shown in the Fig. 1.
Should the bottom afford a good foundation (such as rock) each of the bed
plates H may be supported by one pile formed in the way usually adopted viz.: a
cylindrical tube of sufficient diameter sunk by means of compressed air excavators
or any other suitable process or means, such tubes having a vertical slot in order
to allow of the attachment I on the lifting beds B to slide up and down within
said tube and a central hollow space to permit the movable male screw R to move
up and down as shown in Figs. 5 and 5.
Should the dock be located by the side of a stone pier or a stone wall or strongly
cemented or similar structure the bed plates may be supported upon this structure
and leaving a vertical recess or hollow spaces as before as shown in Figs. 4
and 4*.
According to the circumstances of each case the three arrangements just
previously described may be used in combination if desired or any other similar
or suitable arrangement of foundation may be used as required.
CONSTRUCTION OF PILES.
The various systems of constructing a foundation on piles are too well known to
necessitate a description and no novelty can be claimed in reference to the same ;
but in the special case of using piles with Mitchell's screws (which is the character
of foundation which generally speaking will adapt itself to the requirements of this

page_text: case) the following construction of piles and process of sinking them into the
ground and consolidating them afterwards is considered as novel and best suited
generally to the principal and most important application of this invention-viz. to
docking operations.
The shape of the screw attached to the bottom end of the pile P is of the
ordinary Mitchell's type of a large thread or bearing surface this screw is attached
to a solid pile that is sunk into the ground in the usual way by applying a rotation
motion to the top end of the pile. After the first solid pile P has been driven into
the ground in the ordinary way a second pile t (see Fig. 13) formed of a hollow
cylindrical tube surrounding the previous pile and having another specially shaped
screw fixed at its bottom end is driven into the ground this second screw easily
entering the ground owing to the disturbance thereof already caused therein by
the just previously sunk screw on the pile P.
The inside diameter of the second pile t should be such that a space is left
between it and the solid pile P proportionate to the strength desired.
The space between the two piles should be kept uniform all round and also the
second pile may advantageously be guided in its descent by the one P already
sunk by means of the following arrangement--at the bottom and upper part of the
second pile it carries a rough style of loose fitting ball bearing formed by cast
iron balls of uniform diameter which loosely fill up the space between the two
piles. The balls should be fitted between two projecting ribs inside the second
pilet so that the balls are carried down with the pile in its descent-or other
bearings may be formed within t.
The tubular pile should adapt itself to the outside diameter of the solid pile
without coming in contact therewith except at point of the bearings as shown in
Fig. 13 and these bearings should be so arranged as to freely permit cement or the
like passing same in a plastic state.
The bearing surface of this second screw should be as large as possible and this
surface can be very considerable because this special construction of the double
pile P and admits of the application of the injection of water under pressure in
order to facilitate the sinking of the pile t. The processes of such an injection are
well known and do not necessitate description in the present case the water can be
injected between the two piles P and t and pressed out underneath the screw on t
will diminish the friction while entering the ground and consequently ease the
descent of the screw.
After the screw on t has been driven down to within a certain distance of the
screw on P the annular space between the two piles P and t should be filled in
with liquid or plastic hydraulic or other suitable cement slow to harden and in this
liquid or plastic state forced or pressed downwards by means of hydraulic or other
suitable pressure applied at the top end of the said annular space between the piles
if the pressure be sufficient the cement will be compressed underneath the screw of
the second pilet and will form a solid basis of support and also consolidate the
ground between the two screws. The fluid cement or cement in the plastic state
should also completely fill up the annular space between the two piles P and t-or
if desired the upper part thereof can be completed with hydraulic concrete.
The arrangement for tying (or securing) together the piles in groups is not a
novelty being of the character used in ordinary structures composed of piles or
same may be secured in any other suitable way.
Figs. 1 and 3 show the general plan of ties joining one group of three piles of
the Mitchell type a similar arrangement might be applied to tubes of a larger
diameter supporting each one its own bed-plate H and corresponding male screw R
and female screw G; in the case of using a stone structure for one or both of the
sides of the dock the ties would of course not be necessary.

page_text: means of a set of three girders tying together each group of three piles P as shown
in Figs. 1, 2 and 3 or else cast iron top piece or plate resting on the one separate
iron tube as shown in the Fig. 5 or this plate may rest on a stone pier or wall as
in Fig. 4.
HH Fig. 2 are under supports struts or strengthening pieces to assist the bed
plate H in bearing the stress and strain placed thereon.
The bed-plate H is firmly secured to the said pieces H. The stress or strains to
which the bed-plate H is subject are the vertical strain or stress equivalent to the
load that is to be lifted and the horizontal pull of the driving cable U1 Fig. 2.
The general design of the bed-plate H is shewn in the Figs. 9 and 12. It is of
the shape of a hollow cylinder open at one end and closed at the other and may be
formed of cast steel or other suitable material-the inside surface of the cylinder
should be truly turned-the bottom end of the cylinder should have a hole through
which the male screw R moves and this same bottom end is a plane circular surface
turned from the same centre as the sides of the cylinder itself this horizontal surface
should have a convenient shape so that the rollers Z should fit into the same loosely
and at same time serve to retain the lubricating material for instance shape shown
in Figs. 9 and 12 is very suitable.
ว
The sides or bore of the cylinder H need only be turned smoothly and truly the
ball bearings p that take the horizontal strain against the sides of the cylinder H
(ie. the bed-plate) are held firmly in a grooved lining or piece capable of vertical
adjustment so that the circular ring and the balls p¹ can be adjusted up and down
so as to press more or less on the conical exterior surface of the female screw G
Fig. 12.
The diameter of the cylinder H will vary according to the maximum lateral
strain as well as the vertical strain likely to be placed thereon and same can easily
be fixed when these particulars are known.
Fig. 12 gives a general idea of the design of H.
The bolts that fix the piece v onto the sides of the cylinder H move in a slot
so that may be adjusted (i.e. lowered or raised) and fixed in any position desired
and as the balls get worn this adjustment will permit the lowering of the piece v so
as thereby to keep said bearings adjusted.
THE "MALE" SCREW.
The male screw R may be composed of a solid iron or steel straight bar of a
suitable diameter to bear the maximum strain of the load to be lifted.
In the case
of heavy loads it will be found advantageous to make the screws out of thick solid
drawn steel tubes as those manufactured by the Mannesmann process as tubes of this
kind can be obtained up to large diameters and great lengths. The chief advantage
obtained by a large diameter is that for a given pitch of the thread of the screw
the development of the same is greater and the incline or gradient of the thread
can be smaller the effect of which will be to reduce the actual pull on the driving
cable.
The thickness of the wall of the tube will be determined in proportion to the load
lifted.
The male screw R is screw threaded its whole length and the thread of this
screw is shown in the Fig. 8. The general design of the said male and female
screw threads fitting into and bearing upon each other by intermediate balls under
the action of heavy loads is a very essential point in carrying out this invention and
also the special form of the threads of the screws on the male screw R and in the
female screw G. as shown in Fig. 8-or if desired any other suitable form of thread
ou G and R may be adopted but no claim is herein made to any screw thread other
than that shown in Fig. 8 on both G and H exactly as there shown.
The essential or main features of this kind of thread are:-
(a) That the balls in their natural position when bearing the vertical stress due

page_text: in such a manner as not to be able to turn or rotate upon its own axis.
THE LIFTING BED.
The girders B' of the lifting bed B may be straight ordinary girders composed
of two top and bottom members kept apart at a certain distance by ordinary girder
work such as in the manner generally adopted in bridge work.
The depth of the girder will be limited by the depth of water available.
Each
end of the girder may be fitted on to a steel piece carrying the aforesaid joint and
attachment L. The Fig. 3 gives a general idea of a suitable structure for such
girder.
The general structure of the lifting bed B on which the load or ship is laid is
shewn in Figs. 1 and 2 and the platform or parts thereof can be covered with a
timber flooring or staging A (Fig. 1) to work from etc. and suitable arrangements
should be made in order to prop or support the ship lying on the said lifting
bed B.
The bed may be divided in two or more sections independent of each other so
that in the case of smaller sized vessels it need not be necessary to raise or lower
the whole of the bed B. The dimensions of these sections will have to be fixed
in every special case from a practical point of view and the driving or rotating
of only the necessary female screws to raise or lower such sections is arranged
accordingly.
E
The bed B may be subject to movement imparted to the same by the waves not
only at the time that the bed is raised out of the water (during docking operations)
and the tide is high and the sea rough but also at the time the bed dips in and out
of the water; although it may not be absolutely necessary in every case yet in
some cases it will be very advantageous to resist the action of the waves indepen-
dently from the supports of the lifting bed itself which it is not wise to put to the
test of too much horizontal strain and Figs. 6 & 7 show two arrangements that can
be adopted each one of the sections of the bed B is fitted at its end with guide
wheels of a convenient diameter that turn in bearings firmly and securely fixed
on the bed B itself. The periphery of these wheels are made of a hollow shape
suitable for rolling along a large sized rail that is held in a vertical position and
firmly secured against a stone wall of solid masonry work as shewn in Fig. 6 or
against a large sized strongly cemented tube as in Fig. 7 or any other structure
existent or purposely erected in order to suit every special case; in order to ease
the movement of continual contact of the wheels e against the said vertical rail it
will be convenient to fit a strong hard india rubber band round the wheel so that
the contact may take place between the india rubber and the rail; two or other
number of wheels may be coupled together so as to bear against a corresponding
number of rails placed side by side on the same support.
The system of wheels e can be distributed in whatever positions may suit each
special case.

page_text: bearing counter weights 6 that would assist in clevating the load and Figs. 2 and 3
give an idea of such arrangement. To the top part of the piles is fixed a pulley g
(or system of pulleys g) a cable (or system of cables) firmly attached to the bed B
passes around the groove of the pulley g and hangs towards the outside of the dock.
To the other end of the cable is attached the counter weight that more or less
counter-balances the weight of the bed B. When the bed is lowered in order to
receive the load then the counter weight is raised to its highest position so that
at the start when the load begins to rise the action of the counter weight will help
to raise the load.
The diameter of the pulleys 1 and the number of cables acting on the rim or
grooves of these pulleys will depend on the proportion of the weight of the load
raised by each individual male screw R.
The diameter of the pulleys T will be principally in proportion to the diameter
of the cable and the nature of the material it is made of. For cables of steel wire
or of wire rope the diameter could scarcely come under ten or twelve feet. Should
such diameter of pulleys P prove to be inconvenient then a suitable material would
be a cable formed of a strong leather strap twisted and prepared in a suitable
These cables are very flexible and stand high straius and with these it
will be found sufficient to make the pulleys about five feet in diameter.
manner.
It is advisable that the two pulleys of one group should turn or rotate in opposite
directions.
In applying the motive power that makes the female screws G rotate-the
natural tendency will be to carry the male screws R with them in the revolving
motion and in order to ensure that the male screws R displace themselves vertically
it is indispensable to prevent them from turning and this may be effected as
follows:-
PREVENTING ROTATION OF THE MALE SCREWS R.
Every alternate pulley T of a group of pulleys T rotate in opposite directions
this of course will necessitate that the thread of the male and female screws should
be alternately right and left handed in this way the alternate male screws R of
every group will tend to turn in opposite directions by fixing to the top or bottom
ends of the male screw R the arm of a lever a one on each male screw in a parallel
direction to each other see Fig. 14 fixed to the male screws R so that when these
levers are kept firmly immovable the screws R are kept from moving-now by
simply joining the two ends of the two levers (corresponding to every two
pulleys T) by a strong cable or chain the force that would tend to make the
screws R turn is neutralised on the chain or cable z¹ that moves up and down with
the bed B.
In case of any slight motion of the cables 2¹ it will be sufficient to attach the
centres of these various cables or chains corresponding to each of the sections of
the bed B to one continuous cable y¹ running lengthways to the lifting bed and
firmly attached at both ends to a support anchor pile or mooring.
It would be easy to make arrangements so that the ends or attachments of this
general cable y should move up and down with the bed B if the bed itself is well
guided and protected against horizontal movements. It will be sufficient to attach
the ends of the cable to the bed B itself which is immovable and rigid in a
sufficient measure to accomplish the desired purpose. The Fig. 14 shows the
general arrangements of this gear.

page_text: horizontal pulleys in which arrangement the weight itself of the cable is not
utilised as a tensor of the cable; and on the other hand the pulleys T are so near
each other that the lengths of cable are not sufficient to act by themselves as
tensors. It is essential in order to ensure the pliability of the cables to the grooves
or rims of the pulleys to lead the cable that moves each group of pulleys T through
a suitable tensor or tightening pulley J.
ARRANGEMENT FOR DRIVING THE WHOLE SERIES OF PULLEYS.
The main driving shaft O' will in most cases be found to be most conveniently
situated in the cross piece A' that unites the two sides of the dock see Fig. 15 but
it will be obvious that there are numbers of ways of transmitting the motive power
to the pulleys O that will be found adaptable.
the majority of
The Figs. 1, 2, 3 and 15 show an arrangement adaptable to
cases; each one of the pulleys O is keyed to a horizontal shaft that turns in a
bearing n fixed on to the top landing or structure that unites the top end of the
piles P (composed mainly of the parts H¹ and extra pieces that tie them together).
This same structure supports another set of bearings in which a vertical shaft
turns (Fig. 1) the two shafts and rare at right angles and the motion of is
transmitted to by means of a pair of bevel wheels the diameters of which will be
in the necessary proportion in order to obtain the desired number of revolutions.
The shaft projects towards the outside of the dock and carries on its ends a
pulley that revolves in a parallel plane to the length of the dock these pulleys
can be driven by a hanging cable from a similar pulley O" keyed to the projecting
end of the main shaft O'. These pulleys O" may have as many grooves as may be
necessary in order to transmit the power by means of cables to the various
pulleys O distributed along the sides of the dock. In this way from one main
shaft O' the motion can be transmitted to all the motive pulleys 0 as is indicated
in Fig. 15.

page_text: receptacle din escaping into the air heats the receptacle d" in which the zinc is
first contained.
To the thread of the screw is applied a roller n" (Fig. 22) that fits exactly
into the recess formed by the thread of the screw R. This roller has a revolving
motion and as it revolves dips into the molten zinc in the receptacle and being
thus constantly coated with the zinc it applies the molten zinc to the thread of the
male screw R.
The form of the thread is such that the rollers n¹¹ are inclined and the end that
dips is directed downwards after the zinc has been applied.
The rotation of the roller n¹ is effected by means of two ordinary toothed
wheels w¹ and w₁ from the roller at the same time that it turns this roller ** is
carried in a movable bearing O" and by means of a spring suitably arranged is
pressed with some force on to the thread of the screw. This pressure can be
graduated in many different ways that it is not here necessary to describe.
The wheels w¹ and w¹ can be adjusted as described with reference to a similar
arrangement shown in Fig. 21.
The rollers that form the second part of the apparatus (see Fig. 17) are
simply small rollers that fit into the recess of the screw thread each of these
rollers have their bearings at the end of a lever that is also pressed by means
of a spring (as the Fig. 17 shows) with more or less force against the thread of the
screw. These rollers may be one or more in number and may in succession fit
tighter into the thread of the screw so that each of these rollers tend to press the
coating of zinc with greater force onto the thread.
In the course of turning the frame containing the zinc coating apparatus contact
of the thread takes place with the roller that applies the zine (the plate or
surface of the thread having been previously heated by means of the furnace f")
which comes in near contact with the screw after the application of the zinc the
thread comes in contact next with the plate p₁ that forms the sides of the
furnace in that part which comes in close contact with the thread as shewn in
Fig. 19. After this the thread comes in contact with the succession of different
rollers that press the zinc on to the surface of the screw.
The frame of the apparatus is composed of two parts see Fig. 17 united by bolts
the two pieces may be in two halves and it is unnecessary to enter into any more
details.
Previously to the coating operation just described it is understood that the
thread of the screw will have to be properly cleaned as hereinafter described and
this is done with the aid of the apparatus shown in Fig. 20. The coating should
be applied after the thread has been suitably cleaned such as with an acid solution
so as to remove all traces of foreign matter.
LUBRICATING.
Any suitable means may be adopted for lubricating the various parts requiring
same the parts that more particularly require lubricating are the top part of the
screw G in its working contact with R the bottom part of G and its sides in their
working contact with H and the bottom part of Ġ in its working contact with R
and the ball bearings.
For instance a suitable way to lubricate these working parts R & G would be to
have one general pipe running all along the two sides of the dock from each of
these two main pipes three pipes would be taken off and a special cock be inserted
to give access to these three tubes so that each of these pipes separately can be put
into communication separately from the other or all can be opened together
at will.
The main pipe may be in communication with an apparatus of the same nature as
an accumulator where the lubricant (oil grease etc.) should be compressed in a con-
venient manner and at a fixed pressure sufficient to overcome all the friction in the

page_text: pipes and still force the lubricant in a continual flow onto the working parts
through the auxiliary pipes Q see Fig. 9.
It is sufficient to thus describe the necessary features of such an apparatus
without entering into any details which can be easily varied. The general working
of an accumulator being entirely within the province of every-day practice and 5
this lubricating device is in no way claimed as any part of this invention.
INSERTING AND WITHDRAWING THE BEARING BALLS.
It is evident that considering the number of balls that form part of each bearing
the work involved in the placing and replacing of the balls in their bearings also
the removal of obstructions occasionally when required are operations that unless
performed systematically and in some way akin to automatic would imply a great
deal of labour and render the application of the invention difficult.
In the preceding description in which reference has been made to the shape of
the thread of the screw on R & G it has already been stated that by raising the
male screw R an operation which can be easily performed (by a lever arrangement
by hand or by hydraulic pressure) the parts b c Fig. 8 of the thread come in
contact and the cavity or hollow in which the balls are contained forms one
continual spiral passage or pipe approximately air tight.
At the top of the female screw G there is placed in a direct tangent to the
thread (shown in Fig. 10) a mouth piece n so that by applying a current of air at
a certain pressure the air will be expelled at the bottom of G by a second and
similar mouthpiece n and vice versa if the air under pressure is introduced at the
bottom piece n it will be expelled at the top piece n.
Therefore if a current of compressed air of sufficient pressure-is applied to
the top piece the balls of the bearing will be forced down the thread and expelled
through the bottom piece n.
Supposing a flexible india rubber or strong canvas hose is attached on to the
bottom piece n then the balls will be forced into this hose and if the diameter of
this pipe is approximately that of the balls then if the pipe is long enough the
whole of the balls will place themselves in succession in the pipe where they can be
kept ready for use when required both ends of the hose being stopped.
If on the other hand the balls have to be put into their place after raising the
male screw R it will be enough to attach the india rubber hose to the top piece
and apply the current of air to the end of the pipe the balls will be forced in
succession into their places and by driving or screwing in the plugs / into their
places the balls are secured in their position and the male screw R can be
lowered.
For removing obstacles or simply cleaning the thread of the screws R & G it
will be enough to apply the current of forced air to the top piece n (for example)
remove the lower plug and fit to the bottom piece na grid or other kind of
stopper that will allow the air and any foreign matter to be expelled and yet retain
the balls.
CLEANING THE MALE SCREW THREAD.
The male screw thread cleaning apparatus preparatory to the zinc coating
operation is as follows:-
This apparatus simply consists of a frame that runs on rollers " Figs. 18 & 20
in a similar manner to the frame that carries the coating apparatus that has been

page_text: REPAIRING THE THREAD OF MALE SCREW.
The apparatus shown in Fig. 21 can be fitted at the bottom or top part of G the
general arrangement of this apparatus is shewn in the Fig. 21 and is for the purpose
of repairing the thread of the screw should same be injured.
As the part G rotates the frame of this apparatus rotates as well the roller z" is
pressed against the thread by means of springs as shown in Fig. 21 and con-
sequently this roller turns and by means of two toothed wheels and k
communicates its movement to a spindle carrying a steel milling tool t" that fits
exactly into the thread of R.
The driving wheel or roller z¹¹ is kept constantly pressed against R by means of
springs as aforesaid-which may be adjustable so as to ensure and enforce the
rotation of 2 and to compensate for this spring adjustment and ensure the proper
gearing of k¹ and 4" the bearing carrying the upper part of the spindle of k¹ z" can
be adjusted and secured in the desired position by means of the clamping screw or
adjustment o
Or other means may be employed to repair any abrasion or injury to the thread
of the screw R.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. In a lifting dock or means for bodily raising and lowering ships or other heavy
bodies the arrangement construction and combination of a lifting bed such as B
male screws such as R suspending said lifting bed screw threaded on the exterior
and flexibly connected at their lower ends or so jointed to B as to be unable to turn
on their own axes female screws such as G each revolving in a horizontal plane and
each embracing one said male screw R intermediate bearing balls such as p between
the screw thread on G and that on R a horizontal fixed bed plate or bearing for said
female screw G mounted and fixed in or on any suitable staging platform or
structure and means to revolve said female screw G all substantially in the manner
and for the purposes herein before described and illustrated by way of example in
the drawings hereunto annexed.
2. The arrangement and construction of a tubular pile such as t having a Mitchell
screw or the like on the lower end thereof in combination and acting in conjunction
with a second pile such as P also having a Mitchell screw or the like on the lower
end thereof the first named or outer pile being adapted to slide over the second or
inner pile P means to introduce hydraulic or other fluid cement and pressure into
the interior of the said tubular pilet and means to permit the passing out of said

page_text: cement through the said Mitchell screw on t or adjacent thereto so that the said
cement is injected into the ground either above or below the thread of said screw
or both substantially in the manner and for the purposes hereinbefore described
and as illustrated by way of example in Fig. 13 of the drawings hereunto annexed.
3. The combination of a lifting bed such as B suspending male screws. such as R
suspending said lifting bed and themselves suspended from female screws such as G
intermediate ball bearings between the thread on R and the thread on G and a
horizontal bed plate such as H on which said female screw G horizontally revolves
with a series of double piles such as Pt Fig. 13 forming the supporting structure
from which the load is suspended substantially in the manner and for the purposes
herein before described and illustrated by way of example in Figs. 1 and 2 of the
drawings hereunto annexed.
4. The arrangement and construction of the screw thread on R concave on the
horizontal underneath part of the thread and of a convex formation on the upper
horizontal surface thereof in combination and acting in conjunction with the screw
thread on G concave on the upper horizontal surface of the thread and of a convex
formation on the horizontal underneath surface of the thread thereof as shown in
Fig. 8 of the annexed drawings and having intermediate bearing balls introduced
between these respective opposite concavities on the threads substantially as and for
the purposes herein before set forth.
5. The arrangement construction and combination of parts constituting a lifting
dock or means for bodily raising and lowering ships and other heavy bodies and
apparatus or appliances in connection therewith substantially in the manner and for
the purposes hereinbefore described and as illustrated in the drawings hereunto
annexed.
ted this 3rd day of October 1893.
.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.