US3547213A - Balance comprising capacity weights - Google Patents

Balance comprising capacity weights Download PDF

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Publication number
US3547213A
US3547213A US819228A US3547213DA US3547213A US 3547213 A US3547213 A US 3547213A US 819228 A US819228 A US 819228A US 3547213D A US3547213D A US 3547213DA US 3547213 A US3547213 A US 3547213A
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United States
Prior art keywords
shifting
camshaft
balance
motor
positions
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US819228A
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English (en)
Inventor
Erich Knothe
Eckhard Billin
Franz-Josef Meclcher
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sertorius Werke und Vorma GmbH
Sertorius Werke und Vormals Gottinger Piazisionswaagenfabrik Gmbh GmbH
Original Assignee
Sertorius Werke und Vorma GmbH
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Publication date
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Publication of US3547213A publication Critical patent/US3547213A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G1/00—Weighing apparatus involving the use of a counterweight or other counterbalancing mass
    • G01G1/18—Balances involving the use of a pivoted beam, i.e. beam balances
    • G01G1/26—Balances involving the use of a pivoted beam, i.e. beam balances with associated counterweight or set of counterweights
    • G01G1/28—Balances involving the use of a pivoted beam, i.e. beam balances with associated counterweight or set of counterweights involving means for automatically lifting counterweights corresponding to the load

Definitions

  • Shifting camshaft means are operable to selectively apply any of a plurality of capacity weights to and to remove it fromawei hin mechanism.Aself-lockin ste in [54] BALNCE COMPRIQING CAPACITY WEIGHTS mechanism comprisgs 8% output member operatfiely on 5 Clams 5 Drawmg nected to said shifting camshaft means and an input member [52] US.
  • PATENTEDDECI 519m 7 v 3547213 sum 2 or 3 ERICHVKNOTHE ECHARD BILLIN' FRANZ-JOSEF MELCHER l/zve/zfors K MW Afro/nay PATENTED um 51910 I I 1 sum 3 a; 3
  • This invention relates to a weight-shifting device in a balance having one or more motor-driven shifting camshaft(s).
  • the capacity weights are applied and lifted by shifting arms, which are operated by cams of shifting camshafts.
  • the latter are driven by an electric motor, which is energized by electric contacts at both ends of the balance beam whenever the beam has been deflected to the end of its range of inclination.
  • the or each shifting camshaft of known balances carries a detent cam, which is intended to prevent a standstill of the shifting camshaft in positions other than predetermined locked positions.
  • the brake involves a considerable increase inexpenditure
  • a reliable stopping of the shifting camshaft(s) exactly in its or their shifting positions willbe enforced in that a self-locking stepping mechanism, which is adapted to idle between the stepping movements, is interposed between the drive motor and the shifting camshaft(s).
  • the stepping mechanism may consist of a Maltese cross movement. After each stepping movement, the cam wheel of the Maltese crossmovement can perform more than one-half of a revolution without initiating a new step. During this continued rotation of the cam wheel, the shifting camshaft is locked in its shifting position by the cylinder ratchet ofthe Maltese cross movement.
  • the Maltese cross movement has the additional advantage that each shifting movement of the shifting'camshaft begins slowly, increases in velocity to a maximum, and is retarded thereafter. As a result, the capacity weights, which constitute considerable masses, are gently lifted and applied so that particularly the knife edges and knife edge bearings of the balance are protected.
  • the number of the guide slots formed in the Maltese cross may be as large as the number of shifting positions of the shifting camshaft per revolution thereof. If the shifting camshaft has ten shifting positions, the Maltese cross must then have ten slots.
  • these Maltese crosses may be succeeded by a reduction gearing which is designed so that the product of the number of slots and the reduction ratio equals the number of shifting positions of the shifting camshaft per revolution thereof. For instance, a Maltese cross having four slots will be combined with a reduction gearing having a reduction ratio of 2.5:1 if the shifting camshaft has ten shifting positions.
  • the stepping mechanism may consist of a modified worm'gearing rather than a Maltese cross movement, which modified worm gearing comprises a worm having a helical tooth, which has a lead only around part of its periphery and has no lead in the remaining part of its periphery.
  • modified worm gearing comprises a worm having a helical tooth, which has a lead only around part of its periphery and has no lead in the remaining part of its periphery.
  • a worm gearing has crossing input and output shafts so that the drive motor can be conveniently accommodated in a balance within a small space.
  • FIG. 1 is a perspective view showing an inclination balance having a pan above the beam, a capacity weight mechanism, and a drive therefor.
  • FIGS. 2 and 3 show a four-slot Maltese cross movement in different positions.
  • FIG. 4 shows in a view similar to FIG. 1 a portion of a balance provided with a modified worm gearing.
  • FIG. 5 shows only the worm gearing and its drive motor.
  • FIG. 1 shows a known inclination balance having a pan above the beam. This balance need not be described in detail.
  • a weight bracket 3 isrigidly secured to the pan carrier 1 of the balance and comprises a forked support 8 for each capacity weight 5, 6. For the sake of clarity, only two capacity weights and their supports are shown whereas four capacity weights and supports are normally required for each capacity decade.
  • Weight-shifting levers 10 serve to lift the capacity weights 5, 6 and comprise each a fork 12 for engaging and lifting the capacity weight.
  • the weight-shifting levers 10 are rotatable about a fixed axle l4 and are operable by cams 16, which are secured to the shifting camshaft 18 for rotation therewith.
  • the shifting camshaft carries also a digit wheel 20, which carries ten digits for the applicable weights of a decade.
  • the shifting camshaft is driven by an electric motor 22, which drives the cam wheel 24 of a Maltese cross movement.
  • the Maltese cross 26 has four. guide slots 28.
  • the Maltese cross 26 is secured to a gear 30 for rotation therewith.
  • the gear 30 is in mesh with a gear 32, which is secured to the shifting camshaft 18 for rotation therewith.
  • the gears 30 and 32 form together a reduction gearing.
  • the pitchcircle diameter of gear 32 is 2.5 times the pitch-circle diameter ofgear 30 so that the reduction ratio is 2.5: 1.
  • FIG. 2 the movement is indicated in solid lines in a locked position, in which the cylindrical portion of the cam 24 and one of the concave recesses of the Maltese cross 26 form a cylinder ratchet.
  • the position at the beginning of a stepping movement is indicated in dotted lines in FIG. 2, where the striker pin is shown as it moves into the outer end of a guide slot 28, which extends tangentially to the path of movement of p the striker pin 34 so that the movement of the Maltese cross begins gradually.
  • TheM'altese cross 26 assumes its maximum velocity in the position according to" FIG. 3 and is then gradually retarded until the striker pin 34 tangentially leaves the guide slot 28.
  • the acceleration and retardation of the shifting camshaft are thus gradual rather than sudden.
  • the motor 22 can be operated in both directions of rotation.
  • the motor is energized by a switch, particularly by a light-operated switch, to move in one direction or the other.
  • One revolution of the motor shaft causes the Maltese cross 26 to perform one-quarter of a revolution and the shifting camshaft to perform one-tenth of a revolution. As a result, one or more capacity weights are applied. or lifted.
  • the motor 22 has performed one or more revolutions, as required,
  • the Maltese cross 26 has ten guide slots 28, the reduction gear 30, 32 can be eliminated.
  • the Maltes'e'cross 26 is then directly carried by the shifting camshaft l8.
  • the shiftingcamshaft 18 is also driven by the 38 of the balance.
  • the motor drives the shifting camshaft 18 by means of the modified worm gearing 40, 42.
  • the modified worm 42 has a single tooth 44, which has a-lead only in a small part of its periphery and in the remaining part of its periphery has no lead. This no-lead part is shownat the top and bottom in FIG. and extends throughout the rear side of the worm, which rear side is not shown in FIG. 5.
  • the number of teeth and the number of tooth spaces of the worm wheel are each equal to the desired number of shifting positions of the shifting camshaft 18, which in the present case has ten shifting positions.
  • a balance which comprises a weighing mechanism, a plurality of capacity weights, shifting camshaft means operable to selectively apply any of said capacity weights to and to remove it from said weighing mechanism, a drive motor, and a self-locking Maltese cross movement stepping mechanism drivingly connecting said motor and shifting camshaft means and comprising an output member operatively connected to said shifting camshaft means and an input member operatively connected to said motor and operable thereby to impart predetermined successive stepping movements to said output member and arranged to idle in response toan operation of said motor between successive stepping movements.
  • said shifting camshaft means comprises a rotatable shifting camshaft,which is adapted to assume during each revolution thereof a predetermined number of shifting positions and to shift at least one of said capacity weights relative to .said weighing mechanism as said camshaft reaches each of said shifting positions;
  • said worm gearing comprises a worrnfwheel, which constitutes said output member and has a circular series of teeth in mesh with said screw thread, and tooth spaces between adjacent ones of said teeth;
  • said shifting camshaft means comprises a rotatable shifting camshaft, which is adapted to assume during each revolution thereof a predetermined number of shifting positions and to shift at least one of said capacity weights relative to said weighing mechanism as said camshaft reaches each of said shifting positions
  • said output member comprises a Maltese cross having a plurality of slots
  • said input member comprises a striker pin, which is engageable with each of said slots in succession to impart said stepping movements to said Maltese cross
  • said Maltese cross is operatively connected to said camshaft by a reduction gearing having a predetermined reduction ratio, and the product of the number of said slots and said reduction ratio equals said predetermined number.
  • a balance which comprises a weighing mechanism, a plurality of capacity weights, shifting camshaft means operable to selectively apply any of said capacity weights to and to remove it from said weighing mechanism,a drive motor, and a selflocking stepping mechanism which comprises an output member operatively connected to said shifting camshaft means and an input member operatively connected to said motor and-operable thereby to impart predetermined successive stepping movements to said output member and arranged to idle in response to an operation of said motor between successive stepping movements, said stepping mechanism comprising a worm gearing having a worm, which constitutes said input member and is formed with a helical tooth, and said helical tooth having a lead in one part of the periphery of said worm and nolead in the remaining part of the periphery of said worm.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Transmission Devices (AREA)
US819228A 1968-04-25 1969-04-25 Balance comprising capacity weights Expired - Lifetime US3547213A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES0064748 1968-04-25

Publications (1)

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US3547213A true US3547213A (en) 1970-12-15

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US (1) US3547213A (fr)
BE (1) BE594615A (fr)
GB (1) GB1234897A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3656567A (en) * 1970-10-28 1972-04-18 Sartorius Werke Gmbh Precision balance with automatic locking device
FR2551207A1 (fr) * 1983-08-27 1985-03-01 Sartorius Gmbh Balance d'analyse a plateau superieur
US4766965A (en) * 1986-12-16 1988-08-30 Mettler Instrumente Ag Apparatus for depositing and lifting off of a reference weight in an electronic scale

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113049582B (zh) * 2021-06-02 2021-08-03 天津海关动植物与食品检测中心 一种食品中重金属离子高效检测装置及其方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3656567A (en) * 1970-10-28 1972-04-18 Sartorius Werke Gmbh Precision balance with automatic locking device
FR2551207A1 (fr) * 1983-08-27 1985-03-01 Sartorius Gmbh Balance d'analyse a plateau superieur
US4566548A (en) * 1983-08-27 1986-01-28 Sartorius Gmbh Analytical balance
US4766965A (en) * 1986-12-16 1988-08-30 Mettler Instrumente Ag Apparatus for depositing and lifting off of a reference weight in an electronic scale

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Publication number Publication date
BE594615A (fr) 1960-12-16
GB1234897A (en) 1971-06-09

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