Improvements in the Construction of Scales for Weighing.
Year: 1890

page_text: Date of Application, 23rd June, 1890
Complete Specification Left, 16th Apr., 1891-Accepted, 6th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Scales for Weighing.
1, THOMAS WILLIAMS the Younger, of 45 Myddelton Square, in the County
of Middlesex, Engineer do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in that class of scales which comprises
what are commonly known in the trade as "counter weighing machines" or "counter
scales," wherein a single lever or scale beam is employed, the scale pans or plat-
forms being supported thereby, and steadied and prevented from tipping or canting
to any great extent, by means of "hooks or guides, (generally known as
"topwork" or "bottom work," according to their position above or below the scale
pans) which are connected with their legs" or "pillars" as the case may be.
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The object of my invention is to ensure perfect accuracy and delicacy of action
in scales of this class whatever the position of the weight or load upon the pans or
platforms at the present time the pans or platforms are liable to slightly tip or
cant when a weight is placed near their edges, and this tipping or canting, slight
though it may be, puts à torsional strain upon the "hooks or guides, and creates
an amount of extra friction fatal to all accuracy and delicacy of action.
66
For the purpose set forth, my invention consists essentially in dispensing with
the before mentioned steadying "hooks" or guides, and substituting therefor a
second or auxiliary lever or scale beam, provided at each end with knife edged
bearings for the "legs or pillars" of the scale pans or platforms, and having
its axis of motion upon knife edged centres in vertical alignment with the axis of
motion of the first or main lever or scale beam. The two levers or scale beams
are disposed parallel to one another, and so arranged as to each bear a portion of
the load. I prefer that the points of suspension or support of the two scale beams,
as well as their axes of motion, should be in vertical alignment.
Duh..
CT 1900
E. P. ALEXANDER & SON, Fels. Inst. P.A.,
19, Southampton Buildings, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in the Construction of Scales for Weighing.
I, THOMAS WILLIAMS the Younger, of 45 Myddelton Square, in the County
of Middlesex, Engineer, do hereby declare the nature of this invention, and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement :-
This invention relates to improvements in the construction of that class of scales
wherein the scale pans or platforms are situate above the lever or beam, resting
upon bearings or knife edges carried thereby. In machines of this class, known as
counter weighing machines, and inverted weighing machines, respectively, the scale
pans or platforms are steadied and prevented from tipping or canting to any great
extent by means of "hooks or guides(generally known as "bottom work" or
"top work") which are connected with their legs or pillars.
"
The object of my invention is to ensure increased accuracy and delicacy of action
in scales of the class referred to whatever the position of the weight or load upon
the pans or platforms. In scales of the class referred to as at present constructed
the pans or platforms are liable to slightly tip or cant when a weight is placed near
D77

page_text: their edges, and this tipping or canting slight though it may be puts a strain upon
the "hooks" or "guides" which causes them to bind slightly and creates an amount
of extra iriction fatal to accuracy and delicacy of action.
"
According to my invention I dispense with the before mentioned steadying
"hooks or "guides," and I substitute there for a duplicate or auxiliary lever or
beam working upon knife edges and connected with the legs or pillars of the scale
pans or platforms by knife edged bearings, all its knife edges or bearing points being
in vertical alignment with the corresponding knife edges or bearing points of the
main beam.
In the accompanying drawings in which similar letters refer to corresponding
parts in all the figures,
Fig. 1 shows the principle of my invention diagramatically in its application
either to counter or inverted or other machines. It will be seen that there are two
beams, which are duplicates as regards the distance and position of the bearing
edges, either of which may be considered as the main beam and the other as the
auxiliary beam. The beams, legs or pillars, and bearing blocks, are provided with
suitable knife edges or knife edge bearings. If the pans are placed as shewn in
dotted lines at A the machine is of the counter type. If the pans are placed as
shown in dotted lines at B the machine is of the inverted type. The distances
between the knife edges s and y, a and b, and sand, respectively, should be
equal, so that the weight may be distributed upon both sets of beams. In
practice these distances never are in fact absolutely equal, but this corrects itself
by a slight movement of the knife edges on the concave bearing surfaces. In
some cases it may be advantageous to secure equality by making either the lower
set of blocks d or the upper set o adjustable by means of screws, but in most
cases, with fairly accurate workmanship, no difficulty arises from a very slight
inequality, as the apparatus is not absolutely rigid, and the weight is practically
borne by both beams. When the weight is placed on the extreme outer edge
of a pan, the other end of the leg or pillar carrying the pan tends to move
inward, and this tendency has to be counteracted by the lateral resistance of the
knife edge. This tendency diminishes as the lengths of the legs or pillars i
are increased, and is greatest when they are short. Hence my principle of con-
struction is better adapted to machines such as inverted machines, where more
length in the pillars is permissible, than to counter machines or others in which
increased height is objectionable. In the latter class of machines lateral knife
edges may in some cases be used on the lower beam to take the lateral thrust.
In all cases however the principle as shewn diagramatically in Fig. 1 would be
the same.
In order to describe completely one mode in which my invention may be carried
into practice, I proceed to describe in detail a machine of the inverted type
constructed in accordance with my invention.
Fig. 2 is a side elevation of such a machine.
Fig. 3 is a plan thereof the ornamental top portion being removed.
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a is the main beam the knife edges of which work in the bearings c carried by
the main framing or base d. e is the weight pan and f the goods pan or platform
supported respectively upon the knife edges g and of the main beam. are the
pillars of the scale pans. is the main pillar of the machine secured to the bar
extending across the base d. m is the auxiliary beam the knife edges n of which
rest upon bearings o carried by the box p. At either end of the beam m are
bearings, which receive the knife edges s s extending across the boxes & t¹
carried by the swan necks u u¹ of the pillars i .
The corresponding knife edges or bearing points b, n; g, s; and h, s¹ must be in
vertical alignment.
It is necessary not only that the corresponding knife edges or bearing points of
the two beams should be in vertical alignment but also that the relative positions of
the knife edges or bearings of each beam should correspond. In what is known as
an "accelerating "machine for example the knife edge upon which the beam rocks

page_text: would be slightly below the knife edges or bearing points for the scale pans or
platforms, whilst in what is known as a "vibrating" machine all the knife edges or
bearing points would be in a line, and, in either case, when my invention is applied,
the knife edges or bearing points of the auxiliary beam must be similarly arranged
and the beams must in this respect be duplicates one of the other.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. A weighing machine constructed with duplicate beams, both supported by
knife edges and connected together by means of legs or pillars and knife edges and
knife edge bearings, and having the scales or pans supported by the legs or pillars,
the knife edges or bearings of the two beams corresponding both as to their relative
position and in vertical alignment substantially as described.
2. The use in substitution for the "hooks " or guides ordinarily employed in
machines of the class to which this invention relates, of an auxiliary beam so
disposed and arranged as to bear part of the load, and having its knife edges
or bearing points corresponding as to their relative position, and in vertical
alignment with those of the main beam, substantially as and for the purpose
specified.
3. An improved weighing machine constructed as hereinbefore described with
reference to Figs. 1, 2 and 3.
Dated this 16th day of April 1801
E. P. ALEXANDER & SON, Fels. Inst. P.A.,
19, Southampton Buildings, London, W.C., Agents.