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‘Out. 29, 1946'. -L. s. WILLIAMS . 2,410,139 7 WEIGHING SCALE Filed Feb. 24, 1944 I‘ vi571 ?_ ’ , - , I v Q 5 Sheets-Sheet 1 - Liz/Pence Jul/mirage.‘ lM/y/mms @516/‘M4Z4: AT TORNEYS Oct. 29, 1946. 1.. s. WILLIIAMS 2,410,139 WEIGHING SCALE Filed Feb. 24, i944 5 Sheets-Sheet 2 1|| In I | 2 Q J, _ “0155"”? Oct. 29, 1946. L. S. WILLIAMS ' 2,410,139 WEIGHING SCALE Filed Feb.‘ 24, 1944 5 Sheets-Sheet 5 IIIII II Ill ' INVENTOR. Lawrence 5_ #V/?/ams ATTORNEYS Oct. 29, 1946. ' 2,410,139 L.‘ S. WILLIAMS WEIGHING SCALE ' Filed Feb. 24, 1944 5 Sheets-Shag’; 4 “Elev/A jvgIn“. ?k?m2Qf1“.1w". a a‘ v0”.4 ‘@ _.. “w Iwmm. .»w Il! 67 _ _ INVENTOR. Lawrence 5. ?V/?/a/ns WM ' ATTORNEYS ‘ 0d. 29, 1946. L. s, W|LLIAMS 2,410,139 WE IGHING S GALE Filed Feb. 24, 1944 - 5 Sheets-Sheet 5 73 69 ' INVENTOR. MdW/EWO? 5. MOW/007s . I BY _ , 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.