Repositioning In Response To Deflection Under Load Patents (Class 177/212)
  • Patent number: 4625819
    Abstract: The microbalance includes a mounting having two vertically aligned elongated flexible metal tension members, the upper and lower ends of the tension members being attached to a fixed support. The attachment of one end of each of the tension members to the fixed support is carried out by a resilient tension means. A pivot crossbeam is fixedly attached to the balance beam, and the ends of the pivot beam are fixedly attached respectively to the tension members at points intermediate to the ends. Deflection of the microbalance beam is accommodated by flexure of the metal tension members.
    Type: Grant
    Filed: September 25, 1985
    Date of Patent: December 2, 1986
    Assignee: The Perkin-Elmer Corporation
    Inventor: Michael O'Neill
  • Patent number: 4625818
    Abstract: The invention suggests an intermittent mode of operation to reduce the stray power in the coil in a balance based on the principle of the electromagnetic compensation of force. To this end, switching means (21) are provided which can interrupt the current flow through the coil (11) so that when the current flow is interrupted, the movable parts (2-9) of the balance move against one of the stops (24) or (25). These switching means (21) are controlled by the digital signal processing unit (18). In addition storage means (20) are provided within the framework of the digital signal processing unit which store the last-determined weight value for the duration of the interruption of the current flow through the coil.
    Type: Grant
    Filed: March 18, 1985
    Date of Patent: December 2, 1986
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Franz-Josef Melcher, Christoph Berg
  • Patent number: 4597459
    Abstract: A weight detecting type sensor comprising a roller capable of partly jutting out upwardly from the surface of a body conveying belt, a strut rotatably supporting the roller and having a through-aperture at a portion thereof, a sensor having an optical axis associated with the through-aperture formed in the strut, and a pair of magnets disposed below the bottom of the strut.
    Type: Grant
    Filed: November 28, 1984
    Date of Patent: July 1, 1986
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshiki Iwata, Nobuo Kawase, Yoshinori Tanaka, Takashi Miyake, Hiroshi Kawaura
  • Patent number: 4597458
    Abstract: A balance having a setting means with which the relative precision of the weighing result is to be determined can be set by the user. The balance then adapts automatically to the set relative precision. This adaptation can occur, e.g., in the number of positions displayed, in the step width in the last particular position, in the selection of the integration time, in the filtering of the measured values in the digital signal processing unit, in the frequency of the taking over of the measured value into the display and/or at the time of the emission of the standstill signal or of the measured value release signal.
    Type: Grant
    Filed: October 22, 1984
    Date of Patent: July 1, 1986
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Franz-Josef Melcher, Christian Oldendorf
  • Patent number: 4553618
    Abstract: A weighing cell, in which the weight forces of the load are compensated by deformation or electromechanical forces, includes a load carrier which receives the load, a mechanical-electrical load-measuring cell, and an acceleration meter which experiences the same vertical accelerations as the weighing cell. The load cell and the acceleration meter are connected electrically with one another such that the measuring signal which is adulterated by the acceleration action is corrected correspondingly. The load cell has an output signal (A+a) comprising a weighing signal (A) superposed by a spurious signal (a) due to such acceleration. A subtractor receives the output signal (A+a). The output signal of the acceleration meter is balanced to a value (a').
    Type: Grant
    Filed: August 11, 1983
    Date of Patent: November 19, 1985
    Assignee: Mettler-Waagen GmbH
    Inventors: Karl-Heinz Kusmenskji, Harald Beck
  • Patent number: 4549623
    Abstract: An automatic monitoring system for the constant current source in a balance having electromagnetic load compensation includes circuitry which generates a first current varying in dependence on the constant current and furnishes a digital signal indicative of the value of that current. A microcomputer is provided to compare the digital value to a reference value. If the comparison indicates that the constant current is outside of a given range of values, the microcomputer energizes the display to indicate the presence of an error.
    Type: Grant
    Filed: August 13, 1984
    Date of Patent: October 29, 1985
    Assignee: Mettler Instrumente AG
    Inventor: Arthur Baumann
  • Patent number: 4548288
    Abstract: An electronic balance made free from an error due to ambient temperature variations is disclosed. The balance is characterized in that an electromagnetic force transducer used therein is encased in a constant-temperature casing provided with through hole at the bottom through which a force transmitting means penetrates connecting between a weighing tray and an electromagetic force-coil of said electromagnetic force-transducer. The constant-temperature casing is temperature-controlled at a constant temperature higher than room temperatures to keep said electromagnetic force-transducer free from the effect of ambient room temperature variations.
    Type: Grant
    Filed: February 7, 1984
    Date of Patent: October 22, 1985
    Assignee: Shimadzu Corporation
    Inventor: Akira Komoto
  • Patent number: 4545448
    Abstract: Weighing apparatus of the electromagnetic load compensation return-to-zero type including a vertically displaceable load support member to which is connected a load compensation coil arranged for movement in a stationary magnetic field, characterized in that the magnetic field is produced by at least one permanent magnet mounted in a hollow yoke structure defined by a pair of U-shaped yoke members each formed of a ferromagnetic material. The yoke members are arranged in opposed coaxial relation with their leg portions being parallel and extending toward each other. The yoke members are relatively angularly displaced about their common axis through an angle of 90.degree., the leg portions of one yoke member extending between the leg portions of the other member.
    Type: Grant
    Filed: August 24, 1984
    Date of Patent: October 8, 1985
    Assignee: Mettler Instrumente AG
    Inventor: Peter Kunz
  • Patent number: 4503923
    Abstract: In an electromagnetic balance based on the principle of the eletromagnetic compensation of force a weight-proportional counterforce is generated by a current-carrying coil in a permanent magnet system. An arrangement with annular coil with vertical axis and with a permanent magnetic system constructed symmetrically to the central plane of the coil has proven to be advantageous. However, this arrangement results in a relatively great construction height of the balance. In order to decrease this height, the invention suggests that the soft iron pole plate which is usually present between the like poles of the plates of active magnetic material be reduced in its diameter or entirely eliminated and that the coil be allowed to extend into this area between the plates of active magnetic material. This in conjunction with the use of materials having high coercivity makes a very low constructional height possible.
    Type: Grant
    Filed: March 11, 1983
    Date of Patent: March 12, 1985
    Assignee: Sartorius GmbH
    Inventor: Gunther Maaz
  • Patent number: 4494620
    Abstract: An electric inclination meter is built into a high-resolution electric balance with a measured value receiver, a microprocessor for digital signal processing and with a digital display. This inclination meter compensates the inclination-dependent errors of the balance. The inclination meter can have a movable suspended mass or it can have a container which is partially filled with liquid, thus forming a gas bubble. The positional deviation of the movable elements can be picked up optically or inductively.
    Type: Grant
    Filed: September 8, 1983
    Date of Patent: January 22, 1985
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Franz-Josef Melcher, Eberhard Stadler, Rainer Exner
  • Patent number: 4489800
    Abstract: Electromagnetic load compensation weighing apparatus including a temperature correction circuit having a temperature-responsive element mounted in heat sensing relation relative to the permanent magnet, characterized by the further mounting of a component of the compensating current supply circuit in heat-responsive relation relative to the permanent magnet. A Zener diode serving as a reference voltage device in the compensating current supply circuit is preferably the component that is mounted, together with the temperature-responsive element, in heat conducting relation in a common bore contained within the permanent magnet.
    Type: Grant
    Filed: July 27, 1983
    Date of Patent: December 25, 1984
    Assignee: Mettler Instrumente AG
    Inventors: Bruno Nufer, Paul Luchinger
  • Patent number: 4487280
    Abstract: A correction of temperature errors of the measured value receiver is generally necessary in high-resolution electronic balances. This can be accomplished in a known manner by directly influencing the measured value receiver with the aid of an analogous temperature sensor or by digitizing the output signal of the temperature sensor in a digitizer on the output side and performing the correction in the digital signal processing part. The invention has the task of indicating a circuit which permits the high-resolution digitizer which is present in the balance in any case to be used for digitizing the temperature signal without diminishing its preciseness. A switch (25 in FIG. 1) is provided to this end which feeds the output signal of a temperature sensor (27) to the input of the digitizer (15) in addition to the signal of the measured value receiver (1 . . . 13) at certain times controlled by the digital signal processing unit (22).
    Type: Grant
    Filed: March 31, 1983
    Date of Patent: December 11, 1984
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Franz-Josef Melcher, Christian Oldendorf, J/u/ rgen Ober
  • Patent number: 4487279
    Abstract: An electronic balance whose force equilibrating unit consists of a coarse balancing system and a fine balancing system to obtain a precise value of weight measurement in a short time.
    Type: Grant
    Filed: August 19, 1982
    Date of Patent: December 11, 1984
    Assignee: Shimadzu Corporation
    Inventor: Akira Komoto
  • Patent number: 4470472
    Abstract: A weighing device is disclosed which comprises a frame, a pan element for supporting a load to be weighed, channel members connected to the pan for retaining a plurality of weight elements in a vertically movable manner, a motor supported within the frame, a shaft member operatively connected to and extending from the motor and a plurality of support members each adapted to receive and lift one of the weight elements. Included are circular concentric cam tracks rotating with the shaft member, each of the tracks being positioned under a plurality of the support members. A switch is provided for energizing the motor when the pan is depressed by a load. The motor turns the shaft member and guides the concentric cam tracks alternately into contact with successive support members in a step-by-step manner and thereby lift a corresponding number of the weights substantially equal to the weight of the load.
    Type: Grant
    Filed: July 6, 1982
    Date of Patent: September 11, 1984
    Assignee: Pitney Bowes Inc.
    Inventor: Walter E. Miller
  • Patent number: 4470473
    Abstract: A weighing device is disclosed which comprises a frame, a pan element for supporting a load to be weighed, a channel member connected to the pan for retaining a plurality of weight elements in a vertically movable manner, a motor supported within the frame, a shaft member operatively connected to and extending from the motor and a plurality of vertically movable support members having top end portions adapted to receive and lift one of the weight elements. Two arms are secured to the shaft member and each extends in a direction toward the support members. In one embodiment of the present invention, each support member includes a cam track therein and each of the arms include a cam follower adapted to ride in the cam track. In another embodiment, each support member includes a cam follower extending therefrom and each of the arms include a cam track adapted to receive the cam follower such that the follower can ride in the cam track.
    Type: Grant
    Filed: July 6, 1982
    Date of Patent: September 11, 1984
    Assignee: Pitney Bowes Inc.
    Inventor: Walter E. Miller
  • Patent number: 4470474
    Abstract: A weighing device is disclosed which comprises a frame, a pan element for supporting a load to be weighed, a channel member connected to the pan for retaining a plurality of weight elements in a vertically movable manner, a motor supported within the frame, a shaft member operatively connected to and extending from the motor and a plurality of support members having top end portions adapted to receive and lift one of the weight elements. Two arms are secured to the shaft member and each extends in a direction toward the support members. A switch is provided for energizing the motor when the pan is depressed by a load. The motor turns the shaft member and guides each of the arms alternately into contact with successive support members in a step-by-step manner and thereby lift a corresponding number of the weights substantially equal to the weight of the load.
    Type: Grant
    Filed: July 6, 1982
    Date of Patent: September 11, 1984
    Assignee: Pitney Bowes Inc.
    Inventor: Walter E. Miller
  • Patent number: 4457386
    Abstract: A weighing system of the electromagnetic load compensation type is disclosed including a counter for counting the weight-responsive pulses which are produced during the periods that the compensating current is supplied to the movable coil to return the movable scale member toward its initial no-load position, characterized by the provision of a temperature-responsive device for supplying to the counter a train of temperature-correction pulses that are used to modify the count of the weight-responsive pulses, whereby a more accurate indication of the applied load is obtained. Thus, an analog signal from the temperature sensor is compared with a sawtooth signal to produce a digitalized temperature-responsive signal which modifies the digital weight signal supplied to the microprocessor circuit.
    Type: Grant
    Filed: September 23, 1982
    Date of Patent: July 3, 1984
    Assignee: Mettler Instruments AG
    Inventors: Oskar Schett, Richard Leemann
  • Patent number: 4450924
    Abstract: It is known in high-resolution electronic weighing scales based on the principle of electromagnetic force compensation that the load-dependent development of heat in a coil and a precision resistor can be compensated by sending an additional alternating current through the coil and the precision resistor which is complementarily regulated in its amplitude. In order to regulate the amplitude of this alternating current, the invention proposes a simplified circuit which comprises a highly temperature-dependent resistor, the resistance value of which is set at a fixed theoretical value.
    Type: Grant
    Filed: December 17, 1982
    Date of Patent: May 29, 1984
    Assignee: Sartorius GmbH
    Inventors: Lothar Behrend, Eric Knothe, Franz-Josef Melcher, Jurgen Ober
  • Patent number: 4450923
    Abstract: It is known in high-resolution electronic weighing scales based on the principle of electromagnetic force compensation that the load-dependent development of heat in the coil and the precision resistor can be compensated by sending an additional alternating current through the coil and the precision resistor which is complementarily regulated in its amplitude. In order to make possible a precise regulation of the amplitude of the additional alternating current even in the case of a small carrying force of the electromagnetic force compensation and of a correspondingly small direct compensating current, the invention proposes connecting in a voltage divider in parallel to the coil and the precision resistor which has a highly temperature-dependent resistor. In this parallel branch direct and alternating current are higher by a constant proportionality factor than in the main branch formed by coil and precision resistor.
    Type: Grant
    Filed: December 17, 1982
    Date of Patent: May 29, 1984
    Assignee: Sartorius GmbH
    Inventors: Lothar Behrend, Erich Knothe, Franz-Josef Melcher, Jurgen Ober
  • Patent number: 4429757
    Abstract: A weighing apparatus of the electromagnetic load compensation type is disclosed, including a housing, a load receiver connected for vertical movement relative to the housing, a permanent magnet system connected with the housing for establishing a permanent magnetic field, and an electromagnetic compensating system including a compensation coil connected with the load receiver for movement within the magnetic field. The invention is characterized in that--in order to simplify manufacture and assembly while also achieving low structural height-the permanent magnet system includes a hollow sectional open-ended soft iron yoke member having a generally rectangular cross-sectional configuration, which yoke member is formed from a pair of longitudinally extending generally identical sections. At least one flat permanent magnet is mounted on the inner surface of the yoke member for establishing a flux path therein to generate the magnetic field.
    Type: Grant
    Filed: March 23, 1982
    Date of Patent: February 7, 1984
    Assignee: Mettler Instrumente AG
    Inventor: Peter Kunz
  • Patent number: 4425975
    Abstract: A weighing apparatus is disclosed of the type including a horizontal scale pan carrier connected at one end with a vertical load receiving member that is guided for vertical movement relative to the housing, characterized by the provision of a calibration weight removably mounted on the other end of the pan carrier beneath the scale pan, and a device for raising the calibration weight to an inoperable position relative to the pan carrier arm. In the preferred embodiment, the calibration weight comprises a horizontally arranged U-shaped member the center of gravity of which is arranged below the scale pan. In this manner, a compact and simple arrangement of the calibration weight is provided that furthermore facilitates ease of handling and operation.
    Type: Grant
    Filed: February 12, 1982
    Date of Patent: January 17, 1984
    Assignee: Mettler Instrumente AG
    Inventor: Paul Luchinger
  • Patent number: 4420055
    Abstract: Apparatus for measuring weight and force has a load reception part arranged for deflection on a fixed part of a weighing and force-measuring system and includes a compensation coil arrangement situated in a constant magnetic field. At least one position sensor ascertains load-dependent deflections of the load reception part from a predetermined position and feeds a sensor signal to an electric regulator circuit. The regulator circuit regulates the current through the compensation coil arrangement so that the load reception part is returned to its predetermined position. The regulator circuit includes means which impart, alternately, positive and negative values, determined by the loading, to the current flowing through the compensation coil arrangement.
    Type: Grant
    Filed: August 28, 1981
    Date of Patent: December 13, 1983
    Inventors: Hartmut Grutzediek, Joachim Scheerer, Erich Knothe, Franz-Josef Melcher
  • Patent number: 4417632
    Abstract: For the automatic weighing of a beam balance with electromagnetic force compensation, substitution control weights and digital recording are used. An indicator signals the position of balance beam to a microcomputer. The load compensation is carried out with a limited number of variable electromagnetic compensation forces of constant amplitude, which are produced by means of a corresponding number of discrete constant currents. The currents are graded according to decreasing powers of a numerical system of a suitable basis; as a rule, just like decimally organized figures according to units and powers of ten of these units. Starting out from upper to lower decades, a count is made in each decade as to how many compensation units are needed in order to overcompensate the load. For this purpose, a decision is made merely in the case of every compensation step--without determining precisely the rest position of the balance beam--as to whether the load applied is larger or smaller than the compensation force.
    Type: Grant
    Filed: July 13, 1981
    Date of Patent: November 29, 1983
    Assignee: Battelle Institut e.V.
    Inventor: Peter Lohberg
  • Patent number: 4411328
    Abstract: A weighing device is disclosed which comprises a frame, a pan element for supporting a load to be weighed, a channel member connected to the pan for retaining a plurality of weight elements in a vertically movable manner, a motor supported within the frame and a shaft member operatively connected to and extending from the motor, the shaft member including a spring for supporting the pan element. A plurality of collapsible support members are secured at one end thereof to the frame and each have at their opposite ends a device that is adapted to receive and lift one of the weight elements when the support member is in an extended and non-collapsed position. A camming arm is secured to the shaft member and extends in a direction toward the support members. A switch is provided for energizing the motor when the pan is depressed by a load.
    Type: Grant
    Filed: March 24, 1982
    Date of Patent: October 25, 1983
    Assignee: Pitney Bowes Inc.
    Inventor: David W. Hubbard
  • Patent number: 4382480
    Abstract: A weighing machine employing electromagnetic forces having a weighing pan which is mounted at the top portion thereof. An electromagnetic coil is employed in an air gap of a stationary permanent magnet system for generating a compensating force. The coil has a rectangular shape while the permanent magnet system consists of rectangular plates of magnetically active material with the vertical direction of magnetism being above or below the longer sides of the coil. A horizontal compensating force results.
    Type: Grant
    Filed: July 13, 1981
    Date of Patent: May 10, 1983
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Christoph Berg, Franz-Josef Melcher
  • Patent number: 4375838
    Abstract: An electronic balance includes a weighing means for producing digital output signals as a measured value in response to a force induced upon a tray, a first memory for storing the mass of a reference weight, a discriminator for signalizing the existence and non-existence of an object on the tray, a second memory for storing a corrected value obtained by differentiating between a measured value of the reference weight and the mass stored in the first memory when the discriminator signalizes that no object is placed on the tray, an arithmetic unit for correcting a measured value signalized by the weighing means in accordance with the corrected value stored in the second memory when the discriminator signalizes that an object exists on the tray, and an output unit for permitting of visual inspection of the arithmetic results obtained by the arithmetic unit.
    Type: Grant
    Filed: July 15, 1981
    Date of Patent: March 8, 1983
    Assignee: Shimadzu Corporation
    Inventors: Shozo Yano, Yasuhiro Hujinaga, Toshio Kawara, Akira Komoto
  • Patent number: 4373596
    Abstract: A weighing apparatus with electromagnetic force compensation is disclosed, including a load portion having a first compensation or load coil, and a reference portion having a second compensation or reference coil. An associated permanent magnet system is provided in the form of a partially closed housing having an intermediate wall on which flat permanent magnets are mounted, preferably in pairs. The load coil and the reference coil are arranged on opposite sides of the intermediate wall, thereby providing a compact arrangement which is easy to assemble and which has particular properties in regard to mutual decoupling of the two compensation coils.
    Type: Grant
    Filed: August 14, 1981
    Date of Patent: February 15, 1983
    Inventor: Peter Kunz
  • Patent number: 4372406
    Abstract: An electronic balance includes a system in which a current supplied to a force coil in response to a load applied to the balance is caused to alternate in direction at such a time interval as to permit of no oscillations and in which the measured value is obtained by subtracting the product of the current in the negative direction and a time fraction t.sub.2 for which the same flows from the product of the current in the positive direction and a time fraction t.sub.1 for which the same flows, the sum of said time fractions t.sub.1 and t.sub.2 being equal to each of said time intervals.
    Type: Grant
    Filed: April 28, 1981
    Date of Patent: February 8, 1983
    Assignee: Shimadzu Corporation
    Inventors: Akira Komoto, Tomohiro Tsuji
  • Patent number: 4365680
    Abstract: A force measuring device of the electromagnetic compensation type is disclosed. The force measuring device includes a coil moving in a magnetic field, a display unit and a control circuit which returns the coil to its original position and supplies the display with the value of the forces being measured at substantially the same time. The device is also disclosed including a variable integration constant in the control circuit to provide a quicker response to small disturbances thus making the balance insensitive to vibrations.
    Type: Grant
    Filed: June 19, 1980
    Date of Patent: December 28, 1982
    Inventors: Dietrich Gottstein, Christian Nitschke
  • Patent number: 4354563
    Abstract: This invention relates to weighing apparatus of the electromagnetic load compensation type including a load or compensation coil connected with the load receiving member, and a reference coil connected with the frame for movement independent of the load receiving member, characterized in that the load and reference coils are arranged within separate air gaps of the magnetic field produced by a permanent magnet system mounted on the weighing apparatus frame. In one embodiment, the permanent magnet system includes a permanent magnet having a rotationally symmetrical field, and a magnetic yoke arrangement including an annular outer pole shoe arranged in concentrically spaced relation about an inner pole shoe. An annular ferromagnetic member is arranged in concentrically spaced relation between the inner and outer pole shoes for defining the air gaps in which the reference and load coils are arranged, respectively.
    Type: Grant
    Filed: April 13, 1981
    Date of Patent: October 19, 1982
    Assignee: Mettler Instrumente AG
    Inventors: Paul Luchinger, Andreas Stutz
  • Patent number: 4343373
    Abstract: An electronic weighing apparatus having a load pan, a load receiver forming part of a parallel construction and supporting the pan, weight compensating means, and at least one force-transmitting lever having a short arm and a longer arm, connected at its short arm to take up the force transmitted by the load pan, and connected at its longer arm with the weight compensating means, wherein a built-in calibrating device includes a calibrating lever having an arm connected via a coupling element in force transmitting relation with the load receiver such that the force-transmitting connection can be selectively established or broken.
    Type: Grant
    Filed: March 24, 1981
    Date of Patent: August 10, 1982
    Assignee: Sartorius GmbH
    Inventors: Eberhard Stadler, Dieter Blawert
  • Patent number: 4341275
    Abstract: An electromagnetically compensating measuring apparatus, as in force measuring or weighing devices, wherein a compensation coil is wound upon a coil form movable in the air gap of a stationary permanent magnet system having a pole plate, a capacitive position sensor is connected to detect the position of the compensation coil, and an automatic volume control amplifier is series-connected to the position sensor so as to follow it, with the output of the amplifier connected to feed the compensation coil to tend to hold it in a predetermined zero position, and wherein the coil form and the pole plate each form an electrode of the position sensor.
    Type: Grant
    Filed: March 31, 1981
    Date of Patent: July 27, 1982
    Assignee: Sartorius GmbH
    Inventors: Eberhard Stadler, Franz-Josef Melcher
  • Patent number: 4337838
    Abstract: An improved weighing apparatus of the electromagnetic load compensation type is disclosed, characterized by the provision of a stationary permanent magnet system including two oppositely arranged pairs of spaced parallel flat magnet members that cooperate to define a common air gap. The compensation current coil, which is connected for movement with the movable load-receiving member, is of a flat annular configuration and is contained in the plane of the air gap extending between the magnet members of each pair. The magnet members of one pair are magnetized oppositely from those of the other pair, whereby the magnetic field established across the portion of the air gap between the permanent magnet members of one pair is of a direction opposite that established between the permanent magnet members of the other pair. Consequently, not only can the compensation current for a desired compensation force effect be reduced, but also, the manufacture of the permanent magnet system is greatly simplified.
    Type: Grant
    Filed: April 20, 1981
    Date of Patent: July 6, 1982
    Assignee: Mettler Instrumente AG
    Inventor: Peter Kunz
  • Patent number: 4336854
    Abstract: A weighing device using an electromagnet to attract a load bearing member where the balancing force is sensed using a Hall effect device to sense the force of the magnetic field. Means are provided to produce a signal which is linearly proportional to the weight of the object being weighed.
    Type: Grant
    Filed: October 29, 1980
    Date of Patent: June 29, 1982
    Inventor: William F. Jensen
  • Patent number: 4311202
    Abstract: An improved balance of the electromagnetic load-compensation type is disclosed wherein, in order to improve the temperature-dependent performance of the balance and to reduce the size and amount of operating space required, the load compensation coil (54) is transversely mounted on the balance beam (36) with the plane of the coil extending normal to the longitudinal axis of the balance beam. The load-compensation system also includes a permanent magnet (74) mounted on the balance housing adjacent, spaced from and parallel with the compensation coil, the permanent magnet being magnetized in a direction causing the magnetic field lines to extend parallel with the longitudinal axis of the balance beam, whereby current flowing through the load compensation coil reacts with the magnetic field of the permanent magnet to produce a force on the balance beam that compensates for the load applied to the balance.
    Type: Grant
    Filed: April 17, 1980
    Date of Patent: January 19, 1982
    Assignee: Mettler Instrumente AG
    Inventor: Peter Kunz
  • Patent number: 4300647
    Abstract: A scale of the electromagnetic force compensation principle, having a stationary permanent magnet system with an air gap and at least one coil positioned in the air gap, the coil being acted upon via a position sensor and a variable-gain amplifier by a compensation direct current dependent on the load of the scale, wherein the compensation direct current flows through a measuring resistor from both ends of which a signal dependent on the load of the scale is tapped off and fed to an analog/digital converter, and further electric circuits are connected therewith which permit an alternating current to flow, in addition to the compensation direct current, through the coil and the measuring resistor and including a regulating or adjusting device which modifies the amplitude of the additional alternating current in such a manner that the joulean heat generated in the coil and in the measuring resistor by the compensation direct current and by the additional alternating current is at least approximately load-indepe
    Type: Grant
    Filed: July 23, 1980
    Date of Patent: November 17, 1981
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Franz-Josef Melcher, Jurgen Ober, Lothar Behrend
  • Patent number: 4300646
    Abstract: An electromagnetically compensated precision scale has a load support guided for parallel movement by a guide assembly comprising upper and lower guides defining a triangular shape in plan connected to a housing and to the load support by flexible couplings, and wherein the guides are one-piece and define a vertical joint at the triangle apex, thereby reducing inaccurate readings caused by thermal effects.
    Type: Grant
    Filed: September 27, 1979
    Date of Patent: November 17, 1981
    Assignee: Sartorius GmbH
    Inventors: Franz-Josef Melcher, Christoph Berg, Erich Knothe
  • Patent number: 4293049
    Abstract: Field of the invention: filling machine industry.Device consisting of a lever made up of two arms arranged on each side of a fixed pivoting axis. The end of the first arm supports the end of a rod, movable axially and vertically to rotate the arm and ending at the other end in a load-carrying platform moving downwards as the load increases. The end of the second arm, consisting of two parts pivoting about a movable axis, carries a counter-weight and by sliding along the pivoting part on a fixed axis may itself slide along a straight inclinable rail. By suitable selection of both the weight of the counter-weight and the slope of the straight rail, the lever is balanced at the same time in two positions, one corresponding to zero load on the platform and the other to a predetermined load placed on the platform, there being substantial equilibrium in intermediate positions.Use: Metering of bulk products discharged into containers by filling machines.
    Type: Grant
    Filed: March 17, 1980
    Date of Patent: October 6, 1981
    Assignee: Societe d'Assistance Technique pour Produits Nestle S.A.
    Inventor: Noel Launay
  • Patent number: 4281731
    Abstract: An electromagnetic force-compensating weigher with a load supporting device resiliently supported by resilient joints and movable between stops, wherein electric circuitry is connected to produce a slowly decaying mechanical oscillation upon the load supporting device, to thereby reduce the spring hysteresis of the resilient joints.
    Type: Grant
    Filed: May 8, 1980
    Date of Patent: August 4, 1981
    Assignee: Sartorius GmbH
    Inventors: Walter Sodler, Dieter Blawert, Jurgen Ober
  • Patent number: 4280577
    Abstract: Weighing apparatus of the electromagnetic load compensation type is disclosed including a pivoted transmission lever that connects the compensation coil for movement relative to the stationary permanent magnet field in accordance with the displacement of the load receiving assembly from its initial no-load position, characterized in that the transmission lever is connected with the load receiving assembly via a flexible bearing contained within a hollow coupling part of the load receiving assembly, thereby protecting the bearing against the deleterious influence produced by the different heating rates of the various structural components. By protecting the flexible bearing against component-generated heat as well as extreme variations in ambient temperature, the zero or no-load operating point of the weighing apparatus is protected against temperature-produced errors.
    Type: Grant
    Filed: May 21, 1980
    Date of Patent: July 28, 1981
    Assignee: Mettler Instrumente AG
    Inventor: Peter Kunz
  • Patent number: 4276949
    Abstract: An electromagnetic force-compensating weighing appliance has at least two levers engaged at one of their ends in supporting relationship to a load scale, and each connected at their other ends to a respective compensating coil, the compensating coils being symmetrically disposed in the air gap of a single magnet unit, and the levers being pivotally supported between their ends on fixed supports.
    Type: Grant
    Filed: December 4, 1979
    Date of Patent: July 7, 1981
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Christoph Berg, Franz J. Melcher
  • Patent number: 4261430
    Abstract: A flat weighbridge has a load platform supported by either two one-armed or two two-armed levers arranged at least partly beneath the load platform, wherein one lever is bifurcated to define two spread apart sides and each of the sides bears a supporting device for the load platform, while the other lever bears only one supporting device for the load platform.
    Type: Grant
    Filed: December 4, 1979
    Date of Patent: April 14, 1981
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Christoph Berg, Franz J. Melcher, Dieter Blawert
  • Patent number: 4245711
    Abstract: Weighing apparatus of the electromagnetic load compensation type is disclosed, including a load support connected for movement relative to a frame, a mechanical-transmission ratio-establishing lever connecting the load support with a compensation coil arranged for displacement relative to a permanent magnet arrangement connected with the frame, a position-responsive circuit for supplying compensation current to the coil for creating an electromagnetic force that reacts with the permanent magnet field to maintain the load support in its initial no-load condition, and indicating means for displaying the magnitude of the applied load as a function of the compensation current. To permit the use of the lever in different lever-ratio-establishing environments without the use of attendant balancing weights, the compensation coil is tapped to define a pair of coil portions (28a, 28b) that are alternately energized by a switching device (42) to apply different forces upon the load support.
    Type: Grant
    Filed: August 10, 1979
    Date of Patent: January 20, 1981
    Assignee: Mettler Instrument AG
    Inventor: Peter Kunz
  • Patent number: 4236590
    Abstract: A balance having an electromagnetically compensated loading system and an electromagnetically compensated reference system includes respective signal pathways provided for feeding signals which arise in or are derived from the two systems. These signals are to be compared for measurement. The signals from the two pathways are processed coincidentally with one another for digitization, beginning simultaneously and ending simultaneously.
    Type: Grant
    Filed: January 23, 1979
    Date of Patent: December 2, 1980
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Franz-Josef Melcher
  • Patent number: 4235296
    Abstract: An automatic circuit is provided for a switching motor of electromechanical, self-stabilizing balance having electromechanical compensation. An analog transducer produces an analog measured value which triggers operation of a switching motor whenever an upper or lower limiting value is exceeded, the analog measured value being applicable to a display device. A computer, which actuates a control circuit for the switching motor and the display is connected to the analog transducer via an analog-digital converter, the converter being operatively arranged to derive fine information which is fed to the computer and high-speed coarse or preliminary information which is likewise supplied to the computer ahead of the fine information, which triggers said switching motor in event one or more limiting values is exceeded.
    Type: Grant
    Filed: January 29, 1979
    Date of Patent: November 25, 1980
    Assignee: Sartorius GmbH
    Inventors: Erich Knothe, Franz-Josef Melcher, Franz Rossmann
  • Patent number: 4211295
    Abstract: Method and scale are designed for the manual or automatic weighing of objects of the same nominal weight by means of a scale locked over its measuring system, having a computing device for establishing the weight of the goods to be weighed from the digital output signals of mechanical-electrical converters, e.g. from pre-tensioned measuring strings loaded by the weight of said goods, in which if the load on the measuring system is lower or higher than predetermined limits of the load corresponding to said nominal weight, an electromagnetically generated force acts upon the load support of the scale and prevents the overshooting of said pre-determined load limits.
    Type: Grant
    Filed: July 10, 1978
    Date of Patent: July 8, 1980
    Assignee: Wirth, Gallo & Co.
    Inventor: Mario Gallo
  • Patent number: 4189017
    Abstract: An improved weighing apparatus of the electromagnetic load compensation type is disclosed, including a correction loop connected between the output terminal of the synchronizer and the input terminal of the pulse length modulator for varying the regulated load signal from the PID regulator to produce a corrected regulated load signal which compensates for digitalization errors produced by the synchronizer. In one embodiment, the correction loop includes an integrator circuit for superposing on the regulated load signal an inverted integrated error voltage the magnitude of which is a function of the operation of the synchronizer relative to the mark signals. In a second embodiment, the correction loop includes an integrator circuit that periodically applies to the regulated load signal a constant reference voltage of opposite polarity. Preferably, the reference voltage is applied simultaneously with the periods of supply of the compensation current.
    Type: Grant
    Filed: August 29, 1978
    Date of Patent: February 19, 1980
    Assignee: Mettler Instrumente AG
    Inventors: Felix Strobel, Rudolf Stocker, Werner Zumbrunn
  • Patent number: 4184556
    Abstract: An electromagnetically compensated balance whose magnetic circuit comprises a permanent magnet and a pole shoe associated with each of the two poles of the magnet, one of the pole shoes bounding an air gap in the circuit, includes an induction coil mounted for movement in the air gap, a load carrier movable relative to the circuit under the weight of a carried load, and a force transmitting train connecting the coil to the load carrier for balancing the force exerted by the carried load on the load carrier by a force generated by current flowing in the coil. The force transmitting train includes a force transmitting member fastened to the coil. At least a major portion of the force transmitting member is confined in a space defined between the air gap and the other pole shoe.
    Type: Grant
    Filed: October 19, 1978
    Date of Patent: January 22, 1980
    Assignee: Mettler Instrumente AG
    Inventor: Peter Kunz
  • Patent number: 4179005
    Abstract: Weighing apparatus of the electromagnetic load compensation type is disclosed, including a permanent magnet system connected with the stationary frame, a compensation coil connected with the movable scale member, a system for supplying compensating current to the coil to produce a force for returning the movable scale member to its initial no-load position, and an indicating device for displaying the magnitude of the load applied to the movable scale member as a function of the compensating current, characterized by the mounting of a slotted generally U-shaped conductive metal plate in spaced insulated relation concentrically about the core portion of the permanent magnet system. After the weighing apparatus has been completely assembled, the leg portions of the plate are transformer connected with an alternating-current source for calibrating and/or conditioning the permanent magnet system.
    Type: Grant
    Filed: October 13, 1978
    Date of Patent: December 18, 1979
    Assignee: Mettler Instrumente AG
    Inventor: Peter Kunz
  • Patent number: 4170269
    Abstract: An improved weighing apparatus of the electromagnetic compensation type is disclosed including at least one ferromagnetic member connected with the load-receiving system for reacting with the permanent magnetic field of the apparatus to compensate for the dead-load forces which act on the load-receiving system. Preferably the ferromagnetic members are connected with the coil carrier member in circumferentially spaced relation about the axis of the load receiver member. The permanent magnet which produces the magnetic field and the ferromagnetic members preferably have generally mutually-compensating temperature coefficients of magnetic performance.
    Type: Grant
    Filed: April 21, 1978
    Date of Patent: October 9, 1979
    Assignee: Mettler Instrumente AG
    Inventor: Peter Kunz