IMPROVEMENTS IN HYDROSTATIC WEIGHING MACHINES, APPLICABLE ALSO FOR TESTING CHAINS AND OTHER SIMILAR PURPOSES
Year: 1869

page_text: LETTERS PATENT to Frederic Eliot Duckham, of Millwall, in the
County of Middlesex, Engineer, for the Invention of "IMPROVEMENTS
IN HYDROSTATIC WEIGHING MACHINES, APPLICABLE ALSO FOR TESTING CHAINS
AND OTHER SIMILAR PURPOSES."
Sealed the 1st March 1870, and dated the 16th December 1869.
PROVISIONAL SPECIFICATION left by the said Frederic Eliot Duck-
ham at the Office of the Commissioners of Patents, with his Petition,
on the 16th December 1869.
I, FREDERIC ELIOT DUCKHAM, of Millwall, in the County of Middlesex,
Engineer, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN HYDROSTATIC WEIGHING MACHINES, APPLICABLE ALSO FOR TESTING
CHAINS AND OTHER SIMILAR PURPOSES," to be as follows:-
My Invention relates to improvements in weighing apparatus, in which
a cylinder containing water is employed, the weight of the goods being

page_text: ascertained by the pressure of a piston on the water indicated on a
pressure guage suitably attached.
The object of my Invention is to provide a portable apparatus for
ascertaining the weight of heavy goods during shipment or otherwise,
it being also applicable for use in testing chains, and for other similar
.purposes.
My improvements consist in providing a means of attachment for the
goods to be weighed, whereby they may be suspended from the piston
instead of placing them as hitherto directly on the same. In this
manner I avoid all liability to press unequally upon the piston, and
consequent development of friction between the piston and the sides of
the cylinder, which is frequently the case when the goods are placed on
a platform formed by the top surface of the piston. For this purpose I
suspend the apparatus or cylinder by means of a suitable stirrup piece
connected to a link from a crane, or in other convenient position.. The
goods to be weighed I suspend from the centre of the piston by means
of a piston rod, which passes through a suitable water-tight gland or
packing in the bottom of the cylinder, and to the lower end of which
ród the goods to be weighed are attached. A pressure guage com-
municates as usual with the liquid in the cylinder for the purpose of
indicating the degree of pressure on the same.
Instead of employing a central piston rod passing through the bottom
of the cylinder I may suspend the goods by means of an inverted
stirrup piece similar to that by which the apparatus is sustained, and
which is passed over the top of the piston and down through guides
placed at equal distances apart around the outside of the cylinder, below
which they are united in a link to which the goods may be attached.
In this case the piston must be made of sufficient thickness to project
above the top of the cylinder.
When employed to denote strains for testing purposes the cylinder is
attached at any suitable point, and tension being applied to the piston
rod or stirrup piece the strain will be denoted by the pressure guage,
whether the apparatus be placed in a vertical or other position.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederic Eliot Duckham. in. the Great Seal Patent
Office on the 16th June 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERIC
ELIOT DUCKHAM, of Millwall, in the County of Middlesex, Engineer,
send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of December, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did; for Herself, Her heirs and successors, give
and grant unto me, the said Frederic Eliot Duckham, Her special
licence that I, the said Frederic Eliot Duckham, my exccutors, admi-
nistrators, and assigns, or such others as I, the said Frederic Eliot
Duckham, 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 "IMPROVE.
MENTS IN HYDROSTATIC WEIGHING MACHINES, APPLICABLE ALSO FOR TESTING CHAINS.
AND OTHER SIMILAR PURPOSES," upon the condition (amongst others) that I,
the said Frederic Eliot 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 Frederic Eliot Duckham, do
hereby 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):-
My Invention relates to improvements in weighing apparatus, in
which a cylinder containing water or other liquid is employed, the

page_text: weight of the goods being ascertained by the pressure of the piston on
the liquid indicated on a pressure guage suitably attached.
The object of my Invention is to provide a portable apparatus for
ascertaining the weight of materials in general, and more particularly
heavy goods, during shipment or otherwise; it being also applicable for
denoting strains on chains, and for other similar purposes.
My improvements consist in providing a means of attachment for the
goods to be weighed, whereby they may be suspended from the piston
instead of placing them directly on the same; in this manner I avoid all
liability to press unequally on the piston as well as the consequent
development of undue friction between the piston and the sides of the
cylinder, which frequently occurs when goods are placed on a platform
formed by the top surface of the piston. For this purpose I suspend or
attach the apparatus or cylinder by means of a suitable stirrup piece or
sling connected to a link from a crane or in other convenient position.
The goods to be weighed I suspend from the centre of the piston by
means of a piston rod which passes through a suitable water-tight gland
or packing in the bottom of the cylinder, and to the lower end of which
rod the goods to be weighed are attached. A pressure guage com-
municates as usual with the liquid in the cylinder for the purpose of
indicating the degree of pressure on such liquid, or in other words the
weight of the goods suspended.
Instead of employing a central piston rod passing through the bottom
of the cylinder I may suspend the goods by means of an inverted
stirrup piece, similar to that by which the apparatus is sustained, and
which is passed over the top of the piston and down through guides
placed on the outside of the cylinder, below which it is united in a link,
to which the goods may be attached. In this case the top of the piston
should be made of sufficient diameter to project slightly over the top of
the cylinder.
Instead of suspending the apparatus by means of a sling or stirrup
piece, as herein-before described, it may be mounted in gimbals or
trunnions supported by a bracket or shelf, or the apparatus may be
bolted securely thereto, the goods being attached as previously described.
When employed to denote strains and for other testing purposes the
cylinder is firmly secured in a vertical or other position, and tension

page_text: Figure 1 is an outside elevation of one arrangement of the improved
portable hydrostatic weighing apparatus of my Invention; Figure 2 a plan,
and Figure 3 a sectional elevation of the same taken on line 1-2-3,
Figure 2. A is the cylinder containing water or other suitable liquid,
on the surface of which rests a piston or plunger B, as usual. To this
cylinder A I bolt or otherwise attach a stirrup piece C, by which I
suspend the apparatus from a crane or in other convenient position.
Instead of a stirrup piece the apparatus may be slung by a chain or
chains attached to eye bolts C', C', connected to the cylinder, as shown
in red lines. D is the piston rod passing down through a water-tight
gland or packing E in the bottom of the cylinder A. At the lower end
of this rod D is formed an eye F, to which the goods to be weighed are
attached. The latter are thus suspended from the centre of piston B, on
which the pressure will be uniformly distributed. G is a pressure guage
of any suitable construction, and communicating with the liquid in the
cylinder, as usual, for the purpose of indicating the weight of the goods
suspended from piston rod D, the connection being either through the
back of the guage, as shown in Figure 3, or through the rim of the same,
as shown in Figure 4, or it may be at any other convenient point. The
piston B and gland E I make water-tight either by means of cup
leathers of the usual form, as shown at a, a, in Figure 3, or any other
convenient arrangement may be employed, such, for instance, as that
illustrated in Figure 4, in which a diaphragm a' of leather or other
suitable flexible material is securely clamped in the piston, as shown,
and attached around its edges to the cylinder A by a metal ring A', the
said diaphragm being slightly bulged around the piston, as shown, to
permit of the free movement of the latter.
Figures 5 and 6 illustrate another arrangement in which the goods
are suspended from an inverted stirrup piece instead of from a piston
rod D, as before described. A is the cylinder suspended by rods or
chains C, as before. The plunger B is made preferably of the same
depth as the interior of the cylinder A, so that should the liquid con-
tained by any chance escape, the weight of the goods suspended would

page_text: be equally borne by the whole apparatus. H is the inverted stirrup
piece passing over the top of plunger B, and down through guides I
formed on the outside of cylinder A, beneath which the limbs are united
in a link (or it may be a swivel eye or hook) or connected by a chain,
from which the goods to be weighed are suspended as before. In this
case the gland E is of course dispensed with, the bottom of the cylinder
being formed solid, and the top of the plunger B is rounded and
enlarged, as shown, in order to enable the sling to clear the edge
of the cylinder A, the pressure on the liquid or the weight of the goods
being indicated on a suitable pressure guage, as before. In order to
render the guage capable of indicating heavy weights with precision I
may employ two or more indicators (on the same or separate dials)
geared together so as to show the one the greater and the other the
lesser denominations of weights, the dial or dials being divided accord-
ingly, or I may obtain the same result by the use of a vernier scale in
connection with the indicator.
For the purpose of weighing goods nett I may employ a guage having
a revolving dial plate operated by a rack and pinion or by other means,
so that when the slinging chains or packages representing the tare are
suspended, and the weight of these shown by the indicator, the dial may
be adjusted so that when the goods are suspended the indicator will
again start from zero, and thus indicate the nett weight of the goods.
In some cases, for instance, where it is desired to ascertain the weight
of heavy goods without requiring their removal, or where there is no
other convenient power for lifting them, the cylinder of my apparatus
may be put in connection with a force pump (applied as in the case of
an ordinary hydraulic jack), by which an additional quantity of liquid
may be forced into the cylinder A, so as to lift the piston B sufficiently
to raise the goods from the ground, their weight being indicated on the
pressure guage as before.
I may make the apparatus of any convenient shape externally.
Figure 7 illustrates a modification in this respect, in which a weighing
apparatus and overhauling ball are shown combined, applicable for
cranes where counterweights are now used. In this case the guage is
recessed in the thickness of the ball or cylinder A. In the other
arrangements shown the guage may also be similarly disposed to protect
it from injury.

page_text: This improved weighing apparatus may be used in connection with
existing weighing machines to denote the weight of the goods placed
thereon in lieu of the counterweights now employed.
In an ordinary platform weighing machine, for example, the piston or
plunger of the hydrostatic apparatus may be connected to the main lever
of the weighing platform, the cylinder being attached to the lever handle
of the relieving gear, so as to denote the strain or weight when the
latter is depressed by hand to put the machine in action without any
manipulation of counterweights, the dial of the pressure guage being
graduated to suit.
Having described the nature of my Invention, and the manner of
performing the same, I declare that what I claim as my Invention to be
protected by the herein-before part in recited Letters Patent is,―
1st. Constructing hydrostatic weighing apparatus so that the goods to
be weighed may be suspended therefrom (the apparatus being itself
suspended or attached in any suitable position), as herein-before described
and illustrated in the Drawings annexed.
2ndly. I claim applying this improved construction of hydrostatic
weighing apparatus for denoting strains in testing chains and other
similar purposes, and for use with platform weighing machines and
weighbridges in lieu of the counterweights now employed therewith,
all as herein-before described.
In witness whercof, I, the said Frederic Eliot Duckham, have
hereunto set my hand and seal, this Eighth day of June, in the
year of our Lord One thousand eight hundred and seventy.
FRED. E. DUCKHAM. (L.S.)