IMPROVEMENTS IN WEIGHING AND DYNAMIC MACHINES
Year: 1859

page_text: LETTERS PATENT to Richard Jennings Stevenson Pearce, of Fleet Street,
in the City of London, Machinist, for the Invention of "IMPROVEMENTS
IN WEIGHING AND DYNAMIC MACHINES."
PROVISIONAL SPECIFICATION left by the said Richard Jennings
Stevenson Pearce at the Office of the Commissioners of Patents with his
Petition, on the 16th February 1859.
I, RICHARD JENNINGS STEVENSON PEARCE, of Fleet Street, in the City of
London, Machinist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN WEIGHING & DYNAMIC MACHINES," to be as follows:-
My improvements consist in the application of a constant weight on a lever
as the counterbalance to determine the weight of any body in combination
with a circular dial and index hand to show the result of the weighing
operation. For instance, instead of the lever and shifting weight used in
Fairbank's machine, I employ a somewhat similar arrangement of parts, but
instead of keeping the lever as nearly horizontal as possible and sliding the
weight throughout its length, I allow the lever to assume a vertical position,
& fix the weight at the end, in this position the smallest weights are deter-
mined while as the weights increase the lever approaches the horizontal position,
at which point it determines the greatest weight. I connect this lever with an
arbor carrying an index hand, which may traverse a complete revolution over
the circular dial, and indicate by graduations thereon the weight of the body
weighed. This connection between the lever and the arbor of the index hand
may be by a pinion on such arbor taking into a segment of teeth fixed to the
lever, or it may be by a chain or cord wound round a barrel and attached to
[Price 8d.]

page_text: the lever, the reverse motion of the barrel and arbor being produced by a
weighted cord wound in the opposite direction, or other suitable connection
may be adopted. This same arrangement of lever and index dial is applicable
to various other arrangements of weighing machines.
As a dynamometer I place the weighted lever in a box and combine it as
before with the index hand & dial, the force is applied and transmitted through
a series of levers whereby the machine is kept in its proper position, it is also
applicable in this form to weigh goods while being hoisted or lifted, being
placed between the chain and the goods, in which position the box and appa-
ratus is suspended centrally, and the power or weight also applied centrally,
by which the machine is kept in proper position.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Jennings Stevenson Pearce in the Great Seal Patent
Office on the 16th August 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
JENNINGS STEVENSON PEARCE, of Fleet Street, in the City of London,
Machinist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of February. in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Richard Jennings Stevenson Pearce, Her special licence that I, the
said Richard Jennings Stevenson Pearce, my executors, administrators, and
assigns, or such others as I, the said Richard Jennings Stevenson Pearce, 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 "IMPROVEMENTS IN WEIGHING AND
DYNAMIC MACHINES," upon the condition (amongst others) that I, the said
Richard Jennings Stevenson Pearce, 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.

page_text: NOW KNOW YE, that I, the said Richard Jennings Stevenson Pearce, 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 the application of a weight on a pendant lever as
the counterbalance to determine the weight of any body in combination with
a lever or series of levers and a circular dial and index hand, showing the
result of the weighing operation. For instance, instead of the steelyard and
shifting weight. used thereon in platform machines, I employ a somewhat
similar arrangement of parts for such machines, but instead of keeping the
lever as nearly horizontal as possible and sliding the weight throughout its
length, I allow the lever to assume a vertical position and fix the weight at the
end, in and near this position the smallest weights are determined, while as
the weight increases the lever approaches the horizontal position, in which
position it determines the greatest weight. I connect this lever with an arbor
carrying an index hand which may traverse a complete revolution over the
circular dial, and indicate by graduations thereon the weight of the body being
weighed. This connection between the lever and the arbor of the index hand
may be by a pinion on such arbor taking into a segment of teeth fixed to the
lever, or it may be by a chain or cord wound round a barrel and attached to
the lever, the reverse motion of the barrel and arbor may be produced by a
weighted cord wound in the opposite direction, or by the return of the weighted
lever. This same arrangement of lever and index is applicable to various
other arrangements of weighing machines.
As a dynamometer or large weighing machine I place the weighted lever
in a box as in the small machine, and combine it as before with the index
hand and dial, the force is applied and transmitted through an increased series
of levers whereby the machine is kept in such position that the weighted
lever, when unaffected by force is in a vertical position and at zero; it is also
applicable in this form to weigh goods while being hoisted or lifted, being
placed between the hoisting chain and the goods, in which position the box
apparatus is suspended centrally, and the power or weight also applied centrally
which holds the machine as required for the purpose.
DESCRIPTION OF DRAWINGS, AND ACTION OF THE APPARATUS.
Fig. 1 represents a combination of levers arranged to indicate weight by
means of a dial plate and pointer according to my Invention, the dial plate
being in great part removed in order to show the working parts; and Fig. 2,

page_text: a transverse vertical section of the same. a is the box or case on which the
several parts of the machine are mounted, and of which the dial bencloses the
front; this case may either be fixed on any suitable support, or on the ordinary
pillar of table weighing machines, as in Fig. 3, the strain of the body whose
weight is to be determined being brought to hear on the pendant rod c. This
rod depends from a lever d, hung on knife-edge centres or supports, as well
understood in lever weighing apparatus. The lever d is supported at the end
on the left by a sling or link e from a bracket f: the sling e, supporting the
lever on knife-edges, which form the fulcrum of the lever d. The opposite
end of this lever being the long end is connected by a link with the short
end of a lever h, whose fulcrum is at i, being supported from a bracket 1 fixed
to the case a. The fulcrum and points of support connecting levers d and h
and the link are knife edges, as seen. On the long end of lever han arc k
is formed, which may be a toothed segment taking into a pinion on the arbor
of the index hand or on an arbor m, through which the motion is communi-
cated to the index hand or pointer, but I prefer and have represented the
motion as being communicated to the arbor m by a cord, wire, chain, or
analogous connection. For this purpose I fix a barrel n on arbor m, on
which the cord p has about three turns, and is fixed thereto at the middle of
the length so enrolled on the barrel. The other end of the cord I affix
to an arc q, mounted on the weighted pendant lever r; this lever is repro-
sented as hanging on a knife-edge centre, but it may be suspended on a small
steel pin, to which the eye of the lever is fitted, or it may be on pivot centres.
The end of cord p' is fixed at the left-hand end of arc q. This weighted lever
is the counterbalance of the bodies to be weighed, and by which their
weight is determined. Instead of this lever r being a separate and inde-
pendant part, it may depend from lever h, as represented in red lines. In
this case, however, it would be necessary to hang a weight on the cord p¹ to
bring the barrel n, arbor m, and index hand x back to its original position
after weighing, unless indeed the arc k be a rack, and geared to a pinion on
m, for the purpose of communicating the motion.
It will be readily understood that the pendant weighted lever 7 when
occupying a vertical position requires at first very little power to deflect it
from such vertical position, and it, therefore, when nearest that position,
determines the smallest weights; while the further it departs from that
position, the greater is the power required to raise it, and the more the power
required increases as it rises to the position shown dotted, and beyond it, till it
reaches a horizontal position. This effect is the same, whether the pendant
weighted lever 7 be on an independent fulcrum or supported from h, as shown

page_text: red. The index hand or pointer may be on the arbor m, but I have repre-
sented it in the Drawings as being on a second spindle or arbor s, motion to
which is communicated by the pullies t, t, and small band u, or it may be by
slight pinions gearing with each other. With this arrangement two hands
may be employed; by making the gearing wheels or pinions in the proportion,
say, of two to one, the one hand will pass twice round its dial while the other
moves only once, thus bringing a double graduated circular dial into operation
where the subdivisions are required to be minute, or when used for heavy
weights where a great extent of scale is necessary.
The arbors m and s are mounted in brackets, and in the dial plate in
bearings, which, in order to render the action delicate and sensitive, should be
of steel, of small diameter and accurately made and fitted.
The action of this machine is. this: The case being fixed in position with
the lever 7 vertical and the hand z at zero, the weight is applied at c to hang
on lever d, from which it is transmitted by rod g to lever h, but by reason
of the decreasing leverage of d, in lesser force, it thus acts on h so as to raise
the end and arc k, the force exerted being again diminished by the leverage
of h. The rise of the arc k takes up the cord p, which it partially unwinds
from barrel n; thus causing the arbor m to rotate simultaneously with the
unwinding of cord p; cord p² is wound up on barrel n to an equal extent, and
as a consequence exerting a certain amount of pull on the arc q, thereby
deflecting the weighted lever r to a certain extent, according to the proportion
the weight of the body weighed bears to the weighted lever r, and the
effect of the leverage through which its force is transmitted. The dial or
scale is graduated according to the combinations, so that the hand or pointer *
indicates on the dial the weight of the body required to be ascertained.
It will be readily understood that the greater the weight of the body applied
at c the greater will be the deflection of r from its vertical and normal
position. It will be observed that the pull of the cords p and p' is tangen-
tially to their respective arcs, and directly opposed to each other, the object of
the former being to render the strain uniform, and of the latter to create as
little friction as possible on the bearings of the arbor m. These cords may
of course be separate, and not a continuation of one another; w is a stop to
hold the lever with the hand z in the zero position; y is an adjusting weight
to adjust the balance of the levers accurately, as will be well understood in
ordinary lever machines.
Fig. 4 represents the application of my Invention to a machine for weighing
larger weights than the preceding; it consists simply of the addition of two
levers 1, 2, to the combination through which to transmit and multiply the

page_text: force of the pendant weight lever in its action of counterbalancing and
weighing, as before described. The lever d, instead of being supported from
the bracket f, is connected by rod j with the long end of lever 1; this lever
is suspended from a fulcrum z, supported at the top of case a; the lever dis
also furnished with a bearing d¹, fixed to case a, on which bearing it presses
upwards when in action. The short end of lever 1 is connected with lever 2
by a link 3. The lever 2 is an equal lever, the weight being suspended from
rod c at the centre, while its fulcrum is at 4. The effect produced by the
application of weight at c in this manner is precisely the same as in the last
described machine, the weight of the body applied at c being indicated by the
hand or pointer on the dial. Instead of the numbers and combinations of
levers described herein, other numbers and arrangements of levers may be
adopted, according to the power of the weighing machine, or other circum-
stances. The application of this machine to platform weighing machines will
he readily understood by Fig. 3, the rod c passing down the pillar of that
machine, and additional leverage being used in the platform or not, as
required; this may also be the case in its application to weigh-bridges, and all
of which will be readily understood without further description.
Having described the nature of my Invention, and the manner of per-
forming the same, I declare that what I claim as my Invention, to be pro-
tected by the herein-before in part recited Letters Patent, is,-
First, the application of a pendant lever, to determine weights in com-
bination with levers and index dial and hand, in the manner herein-before
described.
Secondly, the combination of parts herein-before described and shown in
the Drawings hereunto annexed, constituting the lever and dial weighing
machine herein set forth.
In witness whereof, I, the said Richard Jennings Stevenson Pearce, have
hereunto, set my hand and seal, this Sixteenth day of August, in the
year of our Lord One. thousand eight hundred and fifty-nine.
RICH. J. S. PEARCE. (L.S.)
Witness,
W. CLARK, Patent Agent,
53, Chancery. Lane, London.