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Патент USA US2410139

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‘Out. 29, 1946'.
-L. s. WILLIAMS
. 2,410,139
7 WEIGHING SCALE
Filed Feb. 24, 1944
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2,410,139
WEIGHING SCALE
Filed Feb. 24, i944
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Oct. 29, 1946.
L. S. WILLIAMS
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2,410,139
WEIGHING SCALE
Filed Feb.‘ 24, 1944
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INVENTOR.
Lawrence 5_ #V/?/ams
ATTORNEYS
Oct. 29, 1946. '
2,410,139
L.‘ S. WILLIAMS
WEIGHING SCALE
' Filed Feb. 24, 1944
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WE IGHING S GALE
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BY
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ATTORNEYS
2,410,139
Patented Oct. 29, 1946
UNITED STATES PATENT OFFICE
2,410,139
WEIGHING SCALE
Lawrence S. Williams, Toledo, Ohio, assignor to.
Toledo Scale Company, Toledo, Ohio, a corpo
‘ ration of New Jersey
Application February 24, 1944, Serial No. 523,670
8 Claims. (Cl. 265-47)
1
2
There have been many attempts to build weigh~
ing scales incorporating a hydraulic force trans~
mitting system between the load receiver and the
internally and an externally stressed bellows con
nected to a load supporting capsule which will
allow their relative effects to be varied without
disturbing their combined effect.
A still further object is to provide a mounting
arrangement for the pressure receiver of a hy
draulic scale which will permit each pressure re
ceiver and its associated capsule to be removed
or installed asa unit without disconnecting the
counterbalancing mechanism. These hydraulic
systems are advantageous in that they permit
a shallower pit construction and eliminate the
heavy lever system ordinarily used to support the
load receiver.
The hydraulic force transmission systems com
prise pressure transmitting capsules adapted to
hydraulic‘ connection between» them.
More speci?c objects and advantages are ap
parent from the description, in which reference
is had to the accompanying drawings illustrating
forms of hydraulic force transmitting systems
sures into mechanical forces which may be coun 15 embodying the invention.
In the drawings:
terbalanced and indicated by a conventional
Figure I is an elevation, partly in section, of a
weigh beam or similar weighing equipment. By
weighing scale incorporating hydraulic force
making the effective area of the capsules large in
transmitting elements.
comparison with the effective area of the bellows
Figure II is a plan View of the weighing scale,
a relatively large force multiplication is obtained, 20
with parts broken away to show its construction.
i. e. a comparatively small force applied to the
Figure III is an enlarged plan of the hydraulic
bellows can counterbalance a relatively heavy
pressure receiving system and gathering lever
load.
taken substantially along the. line III-III of
In order that a hydraulic force transmitting Figure I.
system shall operate satisfactorily in a weighing
Figure IV is an enlarged elevation of the pres
scale it is necessary that the effective areas of
sure receiving system taken along the line IV--IV
the capsules and bellows remain constant inde
of Figure III.
pendently of the force being transmitted. This is
support the load receiver and to transform the
mechanical forces applied to them into equiv
alent hydraulic pressures, and pressure receiving
bellows adapted totransform the hydraulic pres
Figure V is a fragmentary end elevation of an
true because the effective areas determine the
ratio of
hydraulic pressure to the force at 30 other of the pressure receiving elements taken
substantially along the line V—~V of Figure III.
each end of the system and as the hydraulic pres
Figure VI is a fragmentary end elevation of the
sure is equal throughout the system the ratio of
pressure receiving systems viewed from the line
effective areas is the force transmission ratio.
VI-—~VI of Figure IV.
It has been found possible to construct a pres
Figure VII is a plan view, with parts broken
sure transmitting capsule whose area remains 35
constant within the required. tolerance. How- . away, of an alternative form of pressure receiv
ing and force combining system.
Figure VIII is an elevation, partly in section,
of the pressure receiving system. shown in Figure
ever, commercially obtainable bellows do not
maintain an exactly constant effective area and
their change in area with load produces appreci
able error in the scale indication.
V
The object of this invention is to provide a
40
VII.
-
Figure IX is a plan, partly in section, with some
parts omitted, showing another arrangement of
pressure receiving elements.
Figure X is an elevation, partly in section, taken
mizecl or completely eliminated.
,,
Another object of this invention is to reduce 45 along the line X--X of Figure IX.
These speci?c drawings and the accompany
the error in indication of a hydraulic scale by
ing description is intended to merely illustrate
connecting some of the load supporting capsules
and disclose the invention and not to impose limi
to internally stressed bellows and the remainder
tations on the claims.
of the capsules to externally stressed bellows.
A load receiving platform I0 is supported on
Anotherobject of the invention is to reduce 50
hydraulic force transmission system in which the
error due to changes in bellows area is'mini
girders II which at their ends are carried on
depending brackets I2. The brackets I2 are part
of single link suspensions l3 which also include
stands l4 and'connecting links Hi. The stands
load supporting capsule.
Another object is to provide a mounting for an 55 M are supported on hydraulic capsules l6, each
the error due to effective change in bellows area
by connecting an internally stressed bellows and’
_an externally stressed bellows, in parallel, to each
2,410,139
3
of which has a base member I‘! containing a shal
low ?uid containing recess in which a load sup
porting member I8 is‘ ?tted and hydraulically
supported. The fluid is retained by a ?exible
membrane l9 which seals the space between the
base member I‘! and the load supporting mem
ber l8. Stabilizing rings 20 secured to the stands
4
through a strut 53 whose pointed upper end rests
in a cone-shaped depression in the underside of
the cap 52. The lower end of the strut 53 is
?tted with a bearing 54 which rests on a knife
edge 55 of a knife edge block 56 carried in the
lever 26 similarly to the force transmitting block
43.
The bearing 54 is maintained in position on
l4 or to the load supporting members 18 are inter
the knife edge 55 by an annular ?exure plate 51
connected by an “H" shaped pipe framework 2i
which surrounds the knife edge 55 and is welded
to prevent any tipping of the load supporting 10 or otherwise secured to the ends of the bearing
members I8 in the capsules I6. The space be
surface of the bearing 54 and to points on the
tween the members I1 and I8 of the capsules l6
knife edge block 56 remote from the knife edge
containing the hydraulic fluid communicates
55. The knife edge block 56 is adjusted and
through tubes 22 with bellows 23 of a pressure
locked in position by adjusting screws 58 threaded
receiving system 24. The force created by the
through ?anges in the lever 26. Two of these
hydraulic pressure in the bellows 23 acts be
externally stressed bellows are used in the hy
tween a base 25 and a gathering lever 26 which
draulic scale illustrated in Figure I.
is pivotally supported on fulcrum stands 21
The results of numerous experiments, which
erected from a ?at lower portion of the base 25.
were conducted to determine the errors in hy
The force from the lever 26 is transmitted 20 draulic scales, indicate that a substantial error is
through a stirrup 28, a steelyard rod 29, to a load
attributable to the receiving bellows.
pivot 30 of a weigh beam 3|. The weigh beam 3i
This error, caused by deformation of the bel
is pivotally supported on a fulcrum stand 32
lows under load, appears as a non-linear change
erected on a weigh beam shelf 33 which in turn
in force transmission ratio during the loading
is supported on columns 34 and 35. A poise 35 25 from zero to full capacity. In the case of an in
slidably mounted on the weigh beam 3i is
ternally stressed bellows the effect is a greater
adapted to counterbalance the loads applied to
increase in transmission ratio during the ?rst
the load receiving platform Ill.
half of the load range than during the second
The bellows 23 may be internally stressed by
half, Thus, if the overall ratio is adjusted so the
applying the hydraulic pressure created in the
indication is correct at zero load and full load
capsules l6 to its interior as is indicated in Figure
it will be found “fast” at half load, i. e. indicat
IV. The upper mounting for the bellows 5*‘.3 com
ing more load than is actually on the scale. The
prises a connector 31 which is adapted to
effect with an externally stressed bellows is ap—
mechanically support the bellows and hydrauli
proximately equal and reversed, i. e. the indica
cally connect it to one of the tubes 22 which
tion is “slow” at half capacity when the scale is
leads to one of the capsules l6. The connector
adjusted to be correct at zero and full capacity.
31 is adjusted and locked between arms of a
It is thus possible by using both types of bellows
bracket 38 which in turn is vertically adjustable
in ways 39 of the base 25.
Adjusting screws 46
in one scale to cause the error of one type of
bellows to compensate for the error of the other
threaded through horizontal ?anges 4| at the 40 type.
ends of the ways 39 engage sloped faces 42 of
In the scale shown in Figure I, two internally
the bracket 38 to provide for its vertical adjust
stressed and two externally stressed bellows are
ment and locking.
used, the two internally stressed bellows being
The lower end of the bellows 23 is attached to
connected to capsules at diagonally opposite
a force transmitting block 43 resting in hori-, 45 corners of the load receiver, and the two external
zontal ways 44 of the lever 26. The force trans~
ly stressed bellows being connected to the other
mitting block 43 is adjusted in the lever 26 to
two capsules. Therefore, the force created by.
correct the force transmission ratio and is held
in position by locking screws 45 threaded through
a load on the load receiver which is symmetrically
disposed with respect to the center lines of the
vertical ?anges in the lever 26 at the ends of the 50 platform will be transmitted partly by an in
ways 44. The hydraulic scale of Figure I incorpo
ternally and partly by an externally stressed
rates two such internally stressed bellows 23
‘bellows, and the over-all error of the scale will
connected to capsules located under diagonally
be the difference between the error of the in
opposite corners of the load receiving platform
ternally stressed bellows and the error of the
l0.
55 externally stressed bellows. If the two errors
Bellows may also be externally stressed by
are equal, there is, of course, no net error in the
applying the hydraulic pressure to the outside
indication.
of a bellows enclosed in a surrounding cup
However, if the loads on the platform are
shaped housing. In this arrangement a bellows
ordinarily not symmetrically placed with respect
46 (Figure V) is located in a cup-shaped housing 60 to the center lines, it is desirable that the com
41 supported by a bracket 48 which is mounted
pensation of error effected by a combination of
in ways 49 lying parallel to the ways 39 in the base
internally and externally stressed bellows be
25. The bracket 48 is positioned and locked by
complete for each corner of the platform. This
adjusting screws 56 threaded through the ?anges
4 I. An annularly shaped base 5| is ?rmly sealed
is accomplished by connecting two bellows to
each of the load supporting capsules and by ar—
to the lower end of the bellows 46 and is threaded
ranging them to act in parallel (where each
into the bottom, i. e. the normally open end, of
bellows acts independently on the gathering le
the cup-shaped housing 41. The upper end of
ver). In this arrangement the bellows of each
the bellows 46 is sealed by a cap 52. The space
pair are subjected to the same hydraulic pressure
between the bellows 46 and the cup-shaped hous 70 and by varying the point at which each of the
ing 41 is ?lled with hydraulic ?uid and is con
bellows of each pair acts on the gathering lever
nected by means of one of the tubes 22 to one
their relative efforts may be varied to secure ex
of the capsules l6. The hydraulic pressure from
act compensation of error. A receiving unit em
the capsules thus applied externally tends to col
ploying this modi?cation is shown in plan in
lapse the bellows 46 and thereby exerts force 75 Figure VII and in side elevation in Figure VIII.
2,410,139
5
Hydraulic 1 pressure from I the capsules supporting
the load receiver is transmitted throughtubes 59
and branch pipes 60 .and8l. The branch pipes
‘69 communicate with internally stressed bellows
82' whose upper ends are sealed to connector
blocks 63-whichin turn .arelclamped inlbrackets
‘6'4. The-brackets 64 areadjustably mounted in
.a base structure vE55. The lower ends of the
‘bellows Glare mounted on bellowsbases 56 which
are 'adjustably mounted in a gathering lever 67.
This much of the structure is similar ‘tothe in
ternally stressed bellows ‘23 previously described.
Hydraulic pressure is alsotransmitted through
the other branch pipes?lto cup-shaped housings
'68 which are constructed and mounted in the
same manner as the cup-shaped housing? pre
viously described. An externally stressed bellows
is mounted in each of thecup-shaped housings
.88and by means of struts applies force to knife
stressed ‘bellows 80 ,whichzismounted in a cup
shaped. housing 8 l. The cup-shaped housing 8!
is attached near the edge of the underside of a
circular disk82. .An upper base 83 provided for
the internally stressed bellows ‘I1 is attached to
the underside of the circular disk 82‘ at a point
diametrically opposed to the attachment point
of the cup-shaped housing 8i. In this manner
the internally stressed bellows TI and the exter
nally stressed bellows 80 are mounted parallelly
between the bellows base 69 and the circular
disk 82.
The circular disk 82 has an integrally formed
tenon 83 extending upwardly fromthe center of
15 its upper surface. An upper retaining member
35, through which the tenon 86 passes, is slid
ably mounted between horizontal arms 86 of a
bracket 87 which is adjustably mounted in a
base 88. The upper retaining member 85 is ad
edges adjustably mountedin the‘ gathering lever 20 justable along the arms 88 to correspond with
the adjustment of the lower retaining member
61'. While a small amountof adjustment was
ll along the ways 72 of the lever l3 and is locked
allowed in the mounting .of the internally and
in position by a nut 89 threaded on to its upper
externally stressed bellows 23 and '46, a much
end. The disk 82 is locked to the retaining
larger range of. adjustment is provided when they
areused in parallel with each pair connected to 25 member 85 by a nut 90 screwed onto the tenon
84. The tenon 84, the disk 82, the cup-shaped
one capsule. In this arrangement the force act
housing 8% and the upper base 83 of the bellows
ingon the gathering lever .for a given pressure
are drilled‘ to provide interconnecting ducts
.exerted ‘by the capsule is proportional to the
5H, 92 and 93, by which hydraulic pressure may
sum of the e?ective areasofgthe internally and
be transmitted through the tenon 84 to the bel
externally stressed bellows. If the two bellows
lows ll and 80. The capsule associated with
of each pair have exactly equal and opposite
the receiver is connected by means of a pipe 94
errors and are mountedito act on the lever 61
terminating a union 95 which is screwed into the
at the same effective pivot distance, the error
upper end of the tenon 84.
in one will exactly balance the error in the other.
In this arrangement, the force transmitted to
If-theerrors are not exactly equal, that bellows
the lever 73 by a given hydraulic pressure from
havingthe greater error may be moved closer to
the capsule may be varied by adjusting the re
the fulcrum tosdecrease the effect of that bellows
tainer ‘H in the lever ‘l3 and the upper retainer
on the lever, while the other bellows is moved
85 between the arms 85 of the bracket 81. The
away from the fulcrum to maintain the same
average force transmission ratio. It is thus pos 40 relative effect ‘of the internally and externally
sible .by moving :one or the other or both of the
stressed'bellows may be adjusted without affect
ing the force transmission ratio by rotating the
bellows :to obtain the desired force transmission
ratio v.andat :the same time compensate for the
bellows base '69 and the disk 82. For this to be
true it is'of course necessary-that the internally
‘change .in effective area of‘ the bellows as the
hydraulic pressure is applied.
stressed bellows l‘! and the externally stressed
The independent mounting of each ‘of the
bellows Bil be disposed at exactly equal distances
bellows of each pair. suilfers from the‘ disadvantage
either side the axis of "rotation of the bellows
that whenever an adjustmentis made to secure
base .69 and dislrélz.
a more exact compensation, anotheradjustment
It should be noted that ‘in each illustration,
mustibe madetto restore the average force trans .50 both ends of each bellows mounting may be
mission ratio. Thisdisadvantage may be over
removed from the adjacent structure without dis
come by mounting each pair of bellows :in a
connecting any of the piping. This is a desirable
subassembly which is adjustable as a whole .to
feature in that it allows each capsule with its
secure ratio adjustment and is rotatable to vary
associated bellows and interconnecting tubes to
the effective fulcrum distance of eachbellows to 65 be evacuated and'?lled with the'proper amount of
secure
error
compensation.
Such
a
‘bellows
hydraulic ?uid atnthe factory prior to shipping
mounting is shown in Figures IX and X. The
and installation. It also'allows the substitution
of a new assembly of bellows and capsule for any
subassembly comprises a circular bellows base 69
such assembly which may be damaged or other
provided on its underside with a tenon ‘ID by
means of which it is mounted in a retainer ‘ill. 60 wise rendered un?t for service without encoun
The retainer ‘H is adjustable in ways 12 located
tering the di?iculties inherent in the ?lling of a
in a recessed portion of a gathering lever ‘F3.
‘sensitive hydraulic system in the ?eld.
The retainer ‘H is locked in position by means of
These features of the combination of internally
a pair of cone-pointed locking screws ‘M threaded
and externally stressed bellows units with the pos
through walls 15 of the recess in the gathering 65 sibilities of factory ?lling when combined with
the load supporting capsules which are avail
lever 73. Adjustment of the retainer ‘H in the
able, allows the construction of hydraulic scales
ways 12 varies the distance from the bellows base
having the same accuracy as competing lever
59 to the fulcrum of the lever 13. On the upper
scales without the cost and space requirements of
surface near one edge, the bellows base 69 is ma
chined to form a seat 15 for an internally stressed 70 the heavy levers.
bellows 11. An upwardly extending strut ‘I8 is
Having described the invention, I claim:
1. In a weighing scale incorporating hydrau
studded into the bellows base 69 at a point di
ametrically opposite the seat 18. The strut 18
lic force transmission elements, in combination,
a plurality of capsules supporting a load receiver,
extends upwardly into and engages a cap 19
which seals the upper end of an externally 75 the capsules being adapted to transform mechan
2,410,139
ical force into hydraulic pressure, a plurality of
bellows, one for each capsule, adapted to trans
form hydraulic pressure into mechanical force,
means for hydraulically connecting each capsule
to its corresponding bellows, means for combin
ing, counterbalancing, and indicating the me
chanical force exerted by the bellows, some of
8
lows, said system being adaptable to be assembled
and ?lled with ?uid prior to installation.
5. A hydraulic force transmitting system for
use in a weighing scale comprising a load sup
porting hydraulic pressure transmitter, a pair of
bellows connected to act in parallel, and a benda
ble pipe connecting the hydraulic pressure trans
mitter to the bellows, one of the bellows being
adapted to receive hydraulic ?uid internally, the
being enclosed in chambers and adapted to re 10 other being enclosed in a cup with the hydraulic
ceive hydraulic pressure externally, the capsules
fluid in the space between the cup and the bellows,
connected to the bellows receiving hydraulic pres
said system being adaptable to be assembled and
sure internally being arranged symmetrically
?lled with ?uid prior to installation.
with respect to the capsules connected to the
6. In a weighing scale incorporating hydraulic
other bellows, whereby loads supported by the 15 force transmitting elements, in combination, a
capsules in combination will be correctly indi
plurality of hydraulic capsules supporting a load
cated.
receiver, a plurality of bellows hydraulically con
2. In a weighing scale incorporating hydraulic
nected to the capsules and adapted to actuate load
force transmission elements, in combination, a
counterbalancing means, there being two bellows
plurality of capsules supporting a load receiver 20 connected to each capsule and acting inde
and adapted to transform mechanical force into
pendently on the load counterbalancing means,
said bellows being adapted to receive hydraulic
pressure internally, the remainder of said bellows
hydraulic pressure, a plurality of bellows one for
each capsule adapted to transform hydraulic
pressure into mechanical force, means for hy
wherein one of the two bellows connected to each
capsule is adapted to receive hydraulic ?uid in
ternally, the other being enclosed in a cup-shaped
draulically connecting corresponding capsules 25 housing and adapted to receive hydraulic fluid
and bellows, means for combining, counter-bah
between the housing and bellows, said bellows be
ancing and indicating the forces exerted by the
ing individually adjustable on the counterbalanc
bellows, some of said bellows being adapted to
ing means whereby their relative and combined
receive the hydraulic pressure internally, others
effect on the counterbalancing means may be
01‘ said bellows being con?ned in chambers and '
varied.
adapted to receive hydraulic pressure externally,
‘7. A hydraulic pressure receiving unit adapted
said capsules connected to bellows receiving hy
to transform hydraulic pressure into mechanical
draulic pressure internally being paired. with cap
force comprising a pair of bellows connected in
sules connected to bellows receiving hydraulic
parallel to a hydraulic pressure source, rotatably
pressure externally so that the load supported by 35 and transversely adjustable support members be
each pair of capsules in combination is correctly
tween whose opposed faces said pair of bellows is
indicated. with the error of one bellows compen
mounted, said pair of bellows including one bel
sating i or the error of the other bellows.
lows which receives hydraulic pressure internally
3. In a weighing scale incorporating hydraulic
and one bellows which is enclosed in a chamber
force transmission elements, in‘ combination, a
and receives hydraulic pressure externally.
hydraulic force transmitting system comprising
8. A hydraulic pressure receiving unit adapted
load supporting hydraulic capsules and counter
to transform hydraulic pressure into mechanical
balance actuating bellows in which some of the
force comprising a pair of bellows connected in
bellows are arranged to receive hydraulic pres
parallel to a source of hydraulic pressure, a pair
sure internally and the remaining bellows are
of support members mounted for rotative and
arranged to receive hydraulic pressure externally
transverse adjustment in a base and lever, said
in order that the errors inherent in one type of
bellows being mounted between opposed faces of
bellows may be compensated by the errors inher
said members at equal distances from the axis of
ent in the other type of bellows.
rotative adjustment, one of said bellows being
4. A hydraulic force transmitting system for 50 adapted to receive hydraulic pressure internally,
use in a weighing scale comprising a load sup
and the other adapted to receive hydraulic pres
porting capsule, a pair of bellows connected to act
sure between itself and a surrounding cup, said
in parallel, and a bendable pipe connecting the
rotative adjustment allowing the relative effects
capsule to the bellows, one of the bellows being
of said bellows to be varied and the transverse
adapted to receive hydraulic fluid internally, the
adjustment allowing their combined effect on the
other being enclosed in a cup with the hydraulic
lever to be varied.
?uid in the space between the cup and the bel
LAWRENCE S. WILLIAMS.
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