IMPROVEMENTS IN HYDROSTATIC WEIGHBRIDGES AND PLATFORM WEIGHING MACHINES
Year: 1873

page_text: LETTERS PATENT to Heber Duckham, of Millwall, in the County of
Middlesex, for the Invention of " IMPROVEMENTS IN HYDROSTATIC
WEIGHBRIDGES AND PLATFORM WEIGHING MACHINES."
Sealed the 29th July 1873, and dated the 30th May 1873.
PROVISIONAL SPECIFICATION left by the said Heber Duckham at
the Office of the Commissioners of Patents, with his Petition, on
the 30th May 1873.
I, HEBER DUCKHAM, of Millwall, in the County of Middlesex, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
HYDROSTATIC WEIGHBRIDGES AND PLATFORM WEIGHING MACHINES," to be as
follows:-
Heretofore in hydrostatic weighbridges the platform or table has been
fixed directly upon the top of the ram of the hydraulic cylinder or
cylinders, upon which the weight was consequently liable to press un-
equally if placed nearer one side of the platform than the other, thereby

page_text: developing undue friction between the piston and the sides of the
cylinder.
According to my Invention I construct hydrostatic weighbridges and
platform weighing machines in the following manner:-The platform is
supported upon a single hydraulic cylinder placed centrally beneath it.
This cylinder is inverted, that is to say, it is open at bottom and closed
at top, and is fitted upon a ram or piston rising from a suitable base
plate. The platform or table is supported upon the cylinder by struts
bolted to the platform near the edges and to the lower end of the
cylinder below the level of the ram head, the cylinder bearing also at 1
its lower end against the ram which is firmly fixed to the base plate, so
that all liability of the cylinder being caused to cant is avoided. The
cylinder and platform are sustained by the oil or water contained
between the ram head and the top of the cylinder, the pressure thereon
caused by the weight of the goods on the platform being indicated -
upon a suitable gauge communicating with the liquid space in the
cylinder.
By making the platform circular in shape it may be used on railways
both as a weighbridge and turntable simultaneously, and without
requiring any special adjustment, and will work in the latter capacity:
with very little friction, the weight being entirely supported on the
liquid.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Heber Duckham in the Great Seal Patent Office
on the 29th November 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HEBER
DUCKHAM, of Millwall, in the County of Middlesex, send greeting.
2
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of May, in the year
of our Lord One thousand eight hundred and seventy-three, in the 3
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Heber Duckham, Her special licence
that I, the said Heber Duckham, my executors, administrators, and
assigns, or such others as I, the said Heber Duckham, my executors,

page_text: 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 "IMPROVEMENTS IN HYDROSTATIC
WEIGHBRIDGES AND PLATFORM WEIGHING MACHINES," upon the condition
(amongst others) that I, the said Heber Duckham, 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 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 Heber Duckham, do heroby
declare the nature of my 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 Sheet of Drawings
hereunto annexed and to the letters and figures marked thereon (that is
to say) :-
Hydrostatic weighbridges have been constructed with one or more
bydraulic cylinders placed beneath the platform, but in which arrange-
ments the platform or table was fixed upon the top of the ram or rams
of the said hydraulic cylinder or cylinders. In consequence of this
arrangement the weight was liable to cant the ram if placed nearer one
side of the platform than the other, thereby developing undue friction
between the ram or rams and the sides of the cylinder or cylinders.
My improvements are illustrated in the accompanying Drawing, which
represents a longitudinal vertical section of a hydrostatic weighbridge
constructed according to my Invention :-
A is the weighing table or platform supported upon a single hydro-
static cylinder B placed centrally beneath it, and preferably rising
through an aperture in the platform until the top of the cylinder is on a
level with the platform. This however is not indispensable, as the top
of the cylinder may be just below the platform if preferred, or on the
other hand it may in some cases be even higher than the platform when
the latter is used as a railway turntable for instance. The peculiarity of
the arrangement is that this cylinder being inverted the point of support

page_text: (which is the surface of the liquid on which the top B¹ of the cylinder
rests) is brought up to the level of the platform A, and consequently
nearer to its centre of gravity, instead of the platform being supported
at a point situated at a distance of some feet beneath it as in all existing
hydrostatic weighbridges. The cylinder B is closed at top, as shown, t
and is fitted upon a fixed ram or piston O rising from a suitable base
plate D. E, E, are brackets upon which the platform A is supported
above the cylinder, similar brackets radiating in all directions, so that
the platform will be equally supported on all sides. These brackets are
bolted to the platform near its edges, and rest upon a flange around the
lower edge of the cylinder B, to which they are also bolted, or the
brackets may be cast in one with the platform. The cylinder B is made
to bear at the lower end against a block on the ram C, and thus (the
point of support being at the top of the cylinder as before mentioned
and the latter bearing at two points against the ram) all liability of the
cylinder being made to cant or to press with undue friction upon the
ram is avoided. G is the bearing block, preferably of hard wood, or it
may be of brass or other suitable metal, fixed upon the body of the ram
as shown. The ram head is made tight with cup leather or other
packing, the cylinder and platform being sustained by the oil or water
contained in the space H between the ram head and the top B¹ of the
cylinder. I is a passage through the ram C, communicating with the
liquid space H, and by a strong metal pipe K with a pressure indicator
disposed in any convenient position, in an adjoining office for instance.
The indicator employed is preferably that known as the Bourdon gauge,
or any other upon a similar principle will answer the purpose, the
advantage of this class of gauge being that as its action depends merely
upon the straightening of a bent tube, and as there is no escape for the
fluid (which is almost absolutely incompressible), there will be no friction
between the ram C and the sides of the cylinder. The amount of
pressure upon the liquid caused by the weight of the goods on the
platform will thus be indicated by the gauge with accuracy. L is an
opening closed by a screw plug for filling the cylinder.
By making the platform circular in shape it may be used on railways
both as weighbridge and turntable simultaneously and without requiring
any special adjustment, and will work in the latter capacity with the
least possible friction, the weight being entirely supported by the

page_text: Having described the nature of my Invention and the manner in
which the same is to be performed, I declare that what I claim as my
Invention to be protected by the herein-before in part recited Letters
Patent is, supporting the platform of a hydrostatic weighbridge or plat-
form weighing machine on an inverted cylinder fitted on a fixed ram,
substantially as herein described and shown in the Drawings for the
purpose specified.
In witness whereof, I, the said Heber Duckham, have hereunto
set my hand and seal, this Twenty-fifth day of November, in the
year of our Lord One thousand eight hundred and seventy-
three.