Improvements in Hydrostatic Weighing Machines and Dynamometers.
Year: 1887

page_text: Date of Application, 1st July, 1887
Complete Left, 29th Mar., 1888
Complete Accepted, 4th May, 1888
PROVISIONAL SPECIFICATION.
Improvements in Hydrostatic Weighing Machines and
Dynamometers.
HEBER DUCKHAM Civil & Mechanical Engineer 182 Lewisham Road,
Lewisham S.E. Kent do hereby declare the nature of this invention to be as
follows:-
My invention relates to an arrangement having for its aim the reduction in size,
weight and cost of these Machines whilst at same time it secures greater accuracy and
minimises the risk of Machine becoming deranged and of serious accidents.
I effect my object as follows:-I dispense with the piston nut and to the centre of
piston rod I fit a small diameter and suitably packed ram, which is connected with the
liquid in cylinder by a hole in the side of the piston rod.
Suitable spring or springs are connected with the ram by which they are pressed
against Cylinder Cover or elsewhere-the movement of the ram is communicated to
the Indicator by means of a rod, lever, or other suitable arrangement.
The hole in piston rod necessitating a thin under piston plate; I use an internal
gland to prevent the piston leather being damaged by touching the bottom
of Cylinder.
The piston rod being without the usual nut, the piston plates are screwed to the
piston rod, the joint being made between the plates by means of a gutta-percha ring.
When an attendant is about to read the Indicator lie slightly turns the piston in the
Cylinder to overcome any friction; and by fitting the ram with a Square or Stop to
prevent its turning, the friction of both the piston and ram will be overcome
simultaneously.
The Cylinder cover continues to an eye, although it may be suspended by any other
means, and the Machine may be of any external shape or design.
The Indicator may be of needle, dial, Wheel, Vernier or any other convenient
type and be fixed to the Machine in any position.

page_text: Dynamometers.
HEBER DUCKHAM Engineer 182 Lewisham Road Kent, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
My invention relates to the reduction in size, weight and cost of Hydrostatic Crane
Weighing Machines, securing greater accuracy and minimising the risk of Machines
becoming deranged and of accident.
I effect my object as follows:-
A screwed Cylinder Cover continuing to any oyo A Fig. 1 and fitted with a link or
Shackle is used for suspension, therefore the Machine will always hang true no matter
by what fittings it is attached to Crane. As an alternative, the cylinder & cover
may be in one piece and the bottom of cylinder screwed in.
To the centre of piston rod D I fit a suitably packed ram E which is connected
with liquid in Cylinder by a hole E in side of piston rod.
On the ram is a suitable Collar or plate & on this collar I fit suitable Spring or
Springs which are pressed against Cylinder Cover, or other Convenient Stop,
according to the Weight suspended to the Machine. The movement of ram being
communicated to the Indicator by rod, lever, bell crank, gearing or other suitable
arrangement.
Instead of central Spring as shown I may place several Springs side by side on the
Collar or plate or even put the Springs in the indicator Chamber and connect the ram
to them by lever or other arrangement. In Fig. 3 the ram might be connected
directly with the indicator whether Springs are under cylinder cover or in the
indicator case.
Economical features are the reduced bulk of Machine, the internal gland, the
economy of leather packing both leathers being made from that formerly required for
one, piston plaies screwed to rod & joints made between the piston plates.
The ram is fitted with a Square or Stop of any kind to prevent its turning when
the piston rod is turned and it is obvious that the friction of both piston and ram will
be overcome simultaneously.
The Machine may be of any external Shape or design Fig. 2 and 3.
The indicator may be of Scale, dial, needle, Vernier, lever, dead weight or any
other convenient type.
An important feature is the Casting or Screwing of a Strong indicator Case F to
the Machine and mounting or screwing indicator gearing to cylinder instead of in
Separate Case and distinct Shield as heretofore. The glass being Cemented, as shown,
may be easily removed for renewal etc.
The ordinary tube pressure gauge may be used as Indicator for this improved
Machine either alone or additional_to_the_ram arrangement, in such case the tube is

page_text: screwed directly to the Cylinder instead of in a Separate case and distinct shield as
heretofore the glass being cemented as before mentioned.
The rod or lever passing into indicator Chamber L Fig. 1 may be fitted with a
pliable diaphragm or other suitable arrangement to prevent escaped liquid entering
the indicator Chamber but such diaphragm would not be required in Fig. 3 for where
that design of strap suspension is used the indicator would be fixed on Cylinder Cover
and the ram extended to the indicator chamber-or the springs may be arranged in
the indicator Chamber as before mentioned.
By the use of Cylinder Cover the space occasioned by desconding piston becomes
a receptacle for escaped liquid--this may be drawn off by tap or plug and re-used.
To Shorten the Machine as well as to provide an accurate mode of suspension for
goods, I use a double eyed hook and connect it direct to piston rod by pin and Cotter,
instead of intermediate link used heretofore.
ascertained the nature of my
Having now particularly described and
invention and in what manner the same is to be performed I declare that what
1 claim is:-
1stly. The construction of Hydrostatic Weighing Machines and Dynamometers of
reduced Size, Weight and Cost, improved mode of Suspension the employment of a
ram and Spring or Springs in either manner described to obviate the use of
tube gauges.
2ndly. The casting of fitting combined indicator Case & Shield to Cylinder and
mounting or screwing the indicator gearing directly to cylinder instead of separate
Case and distinct Shield as heretofore & the cementing of glass to allow being
casily removed.
Brdly. Providing receptacle for liquid escaping piston and ram.
4thly. The use of Tube or other gauge on the improved Machine either alone or in
additional to the ram arrangement.
5thly. The double eyed hook connected with pin & Cotter direct to piston rod eye
instead of intermediate link as heretofore.
And I claim to use the whole or any portion of such improvement for the purposes
described.
Dated this 29th day of March 1888.