A FLOATING TURNTABLE FOR USE IN BRIDGES, PIERS, JETTIES, AND OTHER STRUCTURES
Year: 1871

page_text: LETTERS PATENT to Walter Long Granville, of Ivy House, Hampton
Court, in the County of Middlesex, Civil Engineer, for the Invention
of "A FLOATING TURNTABLE FOR USE IN BRIDGES, PIERS, JETTIES, AND
OTHER STRUCTURES,”
Sealed the 1st December 1871, and dated the 7th June 1871.
PROVISIONAL SPECIFICATION left by the said Walter Long Granville
at the Office of the Commissioners of Patents, with his Petition,
on the 7th June 1871.
I, WALTER LONG GRANVILLE, of Ivy House, Hampton Court, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "A FLOATING TURNTABLE FOR USE IN BRIDGES, PIER'S,
JETTIES, AND OTHER STRUCTURES," to be as follows:-
The Invention relates to certain means whereby objects of great
weight may be caused to revolve with facility, and consists in placing
them on the top table of a circular hollow structure or caisson which is
floating in water, instead of turning the objects by the ordinary means

page_text: of a table which revolves on wheels, as in use on railways. By this
means I am able to turn enormously heavy weights with a very small
amount of friction and labour.
The machine is composed of two caissons made of metal, wood, or
other suitable material, one of them being placed within the other, with
sufficient space between them to allow the inner one to revolve freely,
whilst the outer one acts as the guide to the revolving caisson. The
inner caisson must of necessity be floating, but the outer caisson need
not necessarily be floating; it may be fixed on land if desired, or in a
building, as it is a guide to the inner one. Externally it may be made
of any convenient shape.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Walter Long Granville in the Great Seal Patent
Office on the 6th December 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
LONG GRANVILLE, of Ivy House, Hampton Court, in the County of
Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of June, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty- 1
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Walter Long. Granville, Her special
licence that I, the said Walter Long Granville, my executors, adminis-
trators, and assigns, or such others as I, the said Walter Long Granville,
my executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein 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 "A FLOATING
TURNTABLE FOR USE IN BRIDGES, PIERS, JETTIES, AND OTHER STRUCTURES," upon :
the condition (amongst others) that I, the said Walter Long Granville,
my executors or, administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great

page_text: 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 Walter Long Granville, 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
Drawing, that is to say :-
The Invention relates to certain means whereby objects of great
weight may be caused to revolve with facility, and consists in placing
them on the top table of a circular hollow structure or caisson which is
floating in water, instead of turning the objects by the ordinary means
of a table which revolves on wheels, as in use on railways. By this
means I am enabled to turn enormously heavy weights with a very
small amount of friction and labour.
The Drawing represents a turntable constructed in accordance with
the Invention, and adapted to carry a swing bridge.
Figure 1 represents a section, Figure 2 an elevation, and Figure 3 a
half plan and half section of the arrangement.
A is an inner floating caisson constructed of metal, wood, or other
suitable material, on which the object to be turned is placed, which in
the present instance is represented by the two girders B, B, of a swing
bridge; O is an outer caisson of similar construction, which acts as a
guide for the revolution of the inner caisson A, a space being left
between the two to allow the inner one to revolve freely, and admit of
the application of guide rollers D, D, for the purpose of securing
smoothness of action. The outer caisson C is securely moored in position
by anchors or other convenient means. The inner caisson must of
necessity be floating, but the outer caisson need not necessarily be
floating; it may in some cases be fixed and constructed in the form
of a coffer dam, open or not to the flow of the external water, according
to whether it be desired to maintain the turntable at a constant height,
or to allow it to rise and fall with the tide or other difference of water
level; or if applied on land it may be made in the form of a tank con-
taining water in which the inner caisson floats. In some cases it may
be desirable to obtain greater steadiness of the inner caisson than can
readily be obtained from its own floating power, and I then employ
friction rollers or wheels E, E, between the upper platform F of the
turntable and the top of the outer caisson, the buoyancy of the inner

page_text: caisson being so regulated in relation to the weight to be carried that
any desired pressure may be exerted on the outer caisson in order to
obtain the required steadiness and secure the horizontal position of the
turntable.
Having now described the nature of the said Invention, and the
manner in which the samo may be performed, I would have it under-
stood that what I claim as my Invention is, the use of floating turn-
tables constructed and applied substantially as herein-before shewn and
described.
In witness whereof, I, the said Walter Long Granville, have here-
unto set my hand and seal, this Fifth day of December, in the
year of our Lord One thousand eight hundred and seventy-one.