Improvements in the Construction and Arrangement of Special Balances, or Weighing Apparatus, to Adapt such Balances or Weighing Apparatus to the Purpose of Demonstrating the Principles of Weighing.
Year: 1890

page_text: Date of Application, 12th Mar., 1890
Complete Specification Left, 12th Dec., 1890-Accepted, 24th Jan.,, 1891
PROVISIONAL SPECIFICATION.
Improvements in the Construction and Arrangement of Special
Balances, or Weighing Apparatus, to Adapt such Balances or
Weighing Apparatus to the Purpose of Demonstrating the
Principles of Weighing.
I, WILLIAM BEILBY AVERY of the firm of W. & T. Avery 12 Digbeth Birmingham
in the County of Warwick, Manufacturer, do hereby declare the nature of this
invention to be as follows:-
My invention relates to the construction and arrangement of balances and weighing
machines intended to illustrato and demonstrate the principles upon which depend the
accuracy and efficiency of all weighing apparatus. My object is to so modify the
weighing apparatus that all necessary alterations in the relative positions of knife
edges and disposition of the weights in relation to such knife edges may be
readily and rapidly made. In carrying this object into effect I so construct
the weighing beams or steelyards, carrying the knife edges that the beams or
steelyards are jointed at some part or parts of their length. The joints are suitably
constructed to allow the knife edges to be set in any convenient position relatively to
each other and fixed in position by nuts or screws. Instead of joints I may use
sliding picces or combinations of sliding pieces and jointed arms, but in all machines
so constructed that the positions may be set as required for the purpose of illustration
and demonstration.
In applying my invention to any ordinary equal arm weighing beam, I construct
the arms separately and pass the central knife edge, upon which the beam vibrates,
through a suitably shouldered, coned or stepped bolt, having nuts at its extremities.
The inner ends of the two equal arms are shaped to fit on the central bolt and the
nuts serve to screw them home against the shouldered coned or stepped surfaces and
lock them in any desired position. The exterior ends carry the ordinary knife edges
from which the pans are suspended. These knife edges may also be supported in
suitable pieces moving in slots or guides to allow of movement towards or from the
central knife edge upon which the beam vibrates. The movable parts are suitably
indexed to measure the changes made and to allow of the beam being returned to
any position and set in known positions or to allow of the knife edges being set in
any desired and determined position with reference to the length of the beam. At
the centre of the beam I arrange indicating rods above and below or either above or
below, having adjustable gravity bobs which can be moved up or down to change the
position of the centre of gravity of the leam within determined limits. I also
provide a flag to adjust the balance of the two portions of the beam.
An adjustable heam constructed in this manner readily permits of the immediate
demonstration of the principles involved in the construction of weighing apparatus.
Thus I may adjust the two arms so that the plane of action of the central knife
edge coincides with the planes of action of the terminal knife edges, and lock them
by the nuts in that position. I can then prove by actual trial the peculiar properties of
this alignment of the three knife edges and show that if the centre of gravity of
the beams so arranged is adjusted by the gravity bobs to coincide with the centre
of suspension then the beam will remain in any position in which it is set and is
thereby useless for weighing purposes.
By altering the setting to bring the planes of the terminal edges below the centre
of suspension I demonstrate the gradually increasing rapidity of oscillation with
increasing distance of the plane of the terminal knife edges below the central knife
edge.
By altering the setting to raise the plane of the terminal knife edges above that

page_text: of the central knife edge, I demonstrate the properties of the beam in unstable
equilibrium. In like manner I vary the positions of the terminal knife edges along
the length of the beam to show the effect of short as compared with long armed
balances and to make readily visible the effects of unequal arms upon weighing. A
balance constructed according to my invention is very convenient for teaching the
numerous points in connection with weighing apparatus by rapidly changing the
adjustments and demonstrating the effects produced by the changes by actual trial of
the beam under the new conditions.
My invention is applicable to all types of weighing apparatus when beams or steel-
yards are used whether equal or unequal arms are used, and whether simple beams
or steelyards are used, or beams or steelyards combined with lever mechanism designed
to produce parallel motion or to communicate by compound levers a portion of the
weight placed on the weighing platforms or scale pans.
When my adjustable beam or steelyard is combined with parallel motion levers,
the parallel lever connections are arranged similarly to the beam or steelyard con-
nections so that for any change made in the beam or steelyard whether as regards the
position of the knife edge planes, or the positions of the knife edges with regard to
the distance from the central knife edge or balancing knife-edge, a similar change
can he made in the adjustment of the levers and their knife edges.
My invention is thus applicable to the demonstration of the principles of action
and the physical and mechanical properties of all varieties of balances beans. or
steelyards.
Among the more commonly known weighing arrangements which may be so
demonstrated with advantage I may mention the following types: The Beranger
Balance," "The Even Arm or counter weighing machine. "The Dead Weight" or
even balance platform machine of various modifications required in different trades.
"The Compound Leverweighing machine-with-or without loose weights_and_all_
the numerous modifications of such machines as commonly known.
I may apply my invention to all systems of levers and beams used as weighing
apparatus by providing adjustable knife edges either by hingeing the levers or pro-
viding horizontal slots guides or slides, or vertical slots, guides or slides or both, to
change the relative positions of the knife edges in the manner I have described.
Gravity bobs may also be utilized for the purposes I have indicated as applied to
levers as well as weigh beams without departing from the essential features of my
invention.
Dated this 11th day of March 1800.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for Applicant.
COMPLETE SPECIFICATION.
Improvements in the Construction and Arrangement of Special
Balances, or Weighing Apparatus, to Adapt such Balances or
Weighing Apparatus to the Purpose of Demonstrating the
Principles of Weighing.
I, WILLIAM BELLBY AVERY. of the firm of W. & T. Avery, of 12+ Digbeth,
Birmingham, in the County of Warwick, Manufacturer, 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 construction and arrangement of balances and weighing
machines intended to illustrate and demonstrate the principles upon which depend
the accuracy and efficiency of all weighing apparatus. My object is to so modify
the weighing apparatus that all necessary alterations in the relative positions of
knife edges and disposition of the weights in relation to such knife edges may be
readily and rapidly made. In carrying this object into effect I so construct the
weighing beams or steelyards carrying the knife edges that the beams or steelyards
are jointed at some part or parts of their length. The joints are suitably constructed

page_text: to allow the knife edges to be set in any convenient position relatively to each other
and fixed in position by nuts or screws. Instead of joints I may use sliding pieces
or combinations of sliding pieces and jointed arms, but in all machines so constructed
the positions may be set as required for the purpose of illustration and demonstration.
In applying my invention to any ordinary equal arm weighing beam, I construct
the arms separately and pass the central knife edge, upon which the beam vibrates,
through a suitably shouldered, coned or stepped bolt, having nuts at its extremities.
The inner ends of the two equal arms are shaped to fit on the central bolt and the
nuts serve to screw them home against the shouldered, coned or stepped surfaces and
lock them in any desired position. The exterior ends carry the ordinary knife edges
from which the pans are suspended. These knife edges may also be supported in
suitable pieces moving in slots or guides to allow of movement towards or from the
central knife edge upon which the beain vibrates. The movable parts are suitably
indexed to measure the changes made and to allow of the beam being returned to any
position and set in known positions or to allow of the knife edges being set in any
desired and determined position with reference to the length of the beam. At the
centre of the beam I arrange indicating rods above and below or either abovo or
below, having adjustable gravity bobs which can be moved up or down to change
the position of the centre of gravity of the beam within determined limits. I also
provide a flag to adjust the balance of the two portions of the beam.
An adjustable beam constructed in this manner readily permits of the immediate
demonstration of the principles involved in the construction of weighing apparatus.
Thus I may adjust the two arms so that the plane of action of the central knife
edge coincides with the planes of action of the terminal knife edges, and lock them
by nuts in that position. I can then prove by actual trial the peculiar properties of
this alignment of the three knife edges and show that if the centre of gravity of
the beam so arranged is adjusted by the gravity bobs to coincide with the contro
of suspension, then the beam will remain in any position in which it is sot and is
thereby useless for weighing purposes.
By altering the setting to bring the planes of the terminal edges below the
centre of suspension I demonstrate the gradual increasing rapidity of oscillation
with increasing distance of the plane of the terminal knife edges, below the central
knife edge.
By altering the setting to raise the planes of the terminal knife edges above that
of the central knife edge, I demonstrate the properties of the beam in unstable
equilibrium. En like manner I vary the positions of the terminal knife edges along
the length of the beam to show the effect of short as compared with long armed
balances and to make readily visible the effects of unequal arms upon weighing,
A balance constructed according to my invention is very convenient for teaching the
numerous points in connection with weighing apparatus by rapidly changing the
adjustments and demonstrating the effects produced by the changes by actual trial of
the beam under the new conditions.
My invention is applicable to all types of weighing apparatus when beams or
steelyards are used whether equal or unequal arms are used, and whether simple
beams or steelyards are used, or beams or steelyards combined with lever mechanism
designed to produce parallel motion or to communicate by compound levers a
When my
portion of the weight placed on the weighing platforms or scale pans.
adjustable beam or steelyard is combined with parallel motion levers, the parallel
lever connections are arranged similarly to the beam or steelyard connections so
that for any change made in the beam or steelyard whether as regards the position
of the knife edge planes, or the positions of the knife edges with regard to the
distance from the central knife edge or balancing knife edge a similar change can
be made in the adjustment of the levers and their knife edges.
My invention is thus applicable to the demonstration of the principles of action
and the physical and mechanical properties of all varieties of balances, beams or
steelyards.

page_text: "
Among the more commonly known weighing arrangements which may be so
demonstrated with advantage I may mention the following types-The "Beranger
balance, "The Even Arm or counter weighing machine, "The Dead Weight" or
even balance platform of various modifications required in different trades-." The
Compound Lever" weighing machine with or without loose weights, and all the
numerous modifications of such machines as commonly known.
I may apply my invention to all systems of levers and beams used as weighing
apparatus by providing adjustable knife edges either by hingeing the levers or
providing horizontal slots, guides or slides, or vertical slots, guides or slides, or
both, to change the relative positions of the knife edges in the manner I have
described. Gravity bobs may also be utilized for the purposes I have indicated
as applied to levers as well as weigh beams without departing from the essential
features of my invention.
Referring to the three sheets of accompanying drawings—
Figure 1 is a side elevation of an equal arin weighing beam to which my invention
is applied, and Figure 2 is a plan part in section to show the method of jointing
the arms.
or
Figures 3 and 4 are respectively side clevation and plan of an "Even Arin
Counter Weighing Machine" to which my invention has been applied, and these
figures illustrate the mode of adapting the invention to any weighing machine with
parallel motion levers either simple or compound.
Figure 5 is a side elevation of a steelyard with adjustments suitable for the purposes
of demonstration.
-Referring to Figures 1 and 2, the beam is constructed in two parts A and B the
inner ends of which CD are expanded and bored out to fit a coned-or stepped bolt E.
Two nuts E¹, E, serve to lock the arms in any desired position on the bolt. The
holt E (Figure 2) is shown in section through the line ab (Figure 1) and in this case
the bolt and knife edges are made in one piece. The central knife edges however
may be made of a separate piece of steel and passed through a suitable hole drilled in
the bolt E. Each end C, D, carries a pointer such as (by which the exact position
of each arm inay he set by the use of the graduated index F carried on rod Fon
which the bob slides. A similar rod G carries the sliding boh G¹. The rods Fi
and G are attached to the central bolt E so that their position is not affected by
changes in the adjustment of the two arms.
By this arrangement of an equal arm beam it is evident that I can alter the relative
positions of the three knife edges so that the exterior knife edges are either in line
with the central knife edge or above or below it, and so the adjustment of the balance
may be changed to illustrate the points hereinbefore described by me. The external
knife edges are shown fixed to the ends of the team but they may be constructed to
slide towards and from the centre when desired. The gravity bobs it will be readily
understood can be altered to raise or lower the centre of gravity of the beam.
Figures 3 and 4 also illustrate an equal arm weighing beam, but parallel motion
levers are applied to unke it suitable for a counter weighing machine. The parts and
adjustments of the beam are precisely similar to those described with reference to
Figures 1 and 2 and the same letters indicate similar parts. The parallel motion
levers are shown at H, 1, with suitable connecting pieces K, L, and knife edges where
required in order to support the pans M, N, "above the level of the beam. The
levers E, I, may be lengthened or shortened by the slides with thumb nuts hi. The
connecting pieces K, L, may be similarly altered in length by slides and the thumb
nuts k,l while a sliding centre piece O with nuts o permits of adjustment to suit the
lengths of the external pieces. The external knife edges on the arms A, B, may be
made adjustable in a similar manner.
•
Figure 5 is an elevation of a steelyard made in two parts A, B, and jointed at the
centre by a bolt E and suitable nuts E¹ E. The other parts are lettered as in
Figures 1, 2, 3, 4. The bar P is graduated for the movable poise Q and may be
raised or lowered by the screws pp² and the level is indicated by the graduated

page_text: pieces R R'. This allows the plane of suspension of the poise Q to be altered to
show the effect of the alteration. The dotted lines y show the positions of the
two parts A B when the pointers C¹ are moved to their extreme positions on the
graduated surfaces F.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is―
1. The arrangement of adjustable weighing beam, steelyard, or weighing machine
for purposes of demonstration substantially as and for the purposes hereinbefore
described and illustrated in the accompanying drawings.
2. The use of a weighing beam or weighing machine where the arms as A, B, are
jointed at the centre by a shouldered, coned or other bolt as E with nuts,
substantially as and for the purposes hereinbefore described and illustrated in the
accompanying drawings.
3. The use of a weighing beam or weighing machine having parallel levers or com-
pound levers in which adjustments of the levers are applied as shown on the levers H, 1,
and connecting links or pieces K, L, (Figures 3 & 4) of the accompanying drawings
substantially as described.
substantiany as descriv
Dated this 11th day of December 1890.
MARKS & CLERK,
13, Temple Street. Birmingham, Agents for Applicant.