Abstract: A weight switching mechanism for a substitution type analytical balance is provided which permits the automatic selection and lifting of the required substitution weights from the gimbal assembly of a balance beam to allow accurate weighing of an unknown mass. A capacitive/electromagnetic feedback device is provided for sensing changes in the relative balance of the beam with respect to the applied unknown mass. The resultant current is applied to a force coil which maintains the beam in null position. A current related signal is converted to a digital input signal which is applied to a memory and control circuit and electronically displayed. A series of electromagnets, mounted below a printed circuit board and positioned to correspond with each substitution weight, is provided. The printed circuit board is arranged to lift upon release of the balance beam.

Abstract: A weighing system is disclosed of the electromagnetic compensation return-to-neutral type including first and second series-connected compensation coils connected with the weighing pan support, a supply of compensating current connected with the compensation coils, a periodically operable position-responsive switch connected in parallel across the first compensation coil for dividing the compensating current into a continuous first current portion which generally corresponds with the preloading effect of the load support, and a second portion that is periodically supplied to the first coil for periods of time that are a function of the magnitude of the load applied to the load support, and an indicating device responsive only to the second compensating current portion for indicating the magnitude of the load as a function of the compensating current required to return the load support to its neutral position, characterized by the provision of an impedance component electrically connected in parallel with, and

Abstract: A parallel construction, particularly for a top-loading balance with elecmagnetic force compensation, has two essentially identical, preferably trapezoidal, movable guides in parallel horizontal planes. The guides are mounted permanently at one end and connected together by a movable rigid connecting element at the other end. The two guides are displaced relative to one another in their planes at right angles to their axis of rotation.

Abstract: An electromagnetically compensating force-measuring or weighing device includes a working coil disposed in the air gap of a fixed magnetic circuit which includes a permanent magnet. The working coil is subject to the influence of the load to be measured. An indicator responsive to the position of the working coil, has its output fed to a control amplifier, the working coil being fed the output signal from the control amplifier whereby it is brought to the zero position. An additional coil is connected electrically in series with the working coil, the magnetic field produced by the additional coil being determined by a measurement sensor. The output signal of the measurement sensor is a measure of the load to be measured.

Abstract: The magnet system of a top-loading precision balance with electromagnetic load compensation is fixedly fastened in an aluminum alloy frame constituting the fixed link in the parallelogram suspension for the weighing pan. Distortion of the frame under thermal stresses due to the different coefficients of expansion of the ferrous metal of the magnet system and the light metal of the frame is prevented by openings in the frame walls spacedly surrounding the portions of the frame wall fixedly fastened to the magnet system.

Abstract: An improved weighing apparatus of the electromagnetic load compensation type is disclosed, characterized by the provision of a horizontal one- or two-arm lever connected at one end with a compensation coil carrier device, a first bearing device connecting said lever for pivotal movement in a vertical plane relative to a pot-type permanent magnet, and a second bearing device connecting the pan carrier member with the lever. Preferably the first and second bearing devices comprise vertical flexible hanger straps that are bendable about parallel horizontal axes. In the one-arm embodiment, the lever is connected at its other end with the permanent magnet by the first bearing device, the pan carrier member being connected by the second bearing device to an intermediate portion of the lever. In the two-arm embodiment, an intermediate portion of the lever is connected with the permanent magnet by the first bearing device, and the other end of the lever is connected with the pan carrier by the second bearing device.

Abstract: This force measuring apparatus includes a balance beam, means for applying a force representative of a load to be weighed to the balance beam, and means for applying counterweights in preselected steps to the balance beam. A signal is picked up from the position of the beam and is used to actuate a display indicating the weight of the load. The balance beam moves within a limited range of positions. Whenever it approaches one end of its limited range, a maximum or minimum signal is produced and controls a motor to drive the counterweight means to apply counterweights to the beam or to remove counterweights, as required to restore the balance beam to its limited range of positions. The display is concurrently reset to compensate for the change in the counterweight, so that the display accurately indicates the weight of the load.

Abstract: Weighing apparatus of the electromagnetic compensation type is disclosed, wherein the compensation coil means is continuously supplied with a first component of compensation current which at least partially compensates for the no-load preloading effect of the movable pan carrier system, said coil means being periodically supplied with a second component of compensation current which is a direct function of the magnitude of the load being weighed. Indicating means are provided which are responsive to the magnitude of the second current component to present a visual indication of the magnitude of the load being weighed. In one embodiment, separate sources of compensation current and counter pulses are provided, while in a second embodiment the compensation current is obtained from a pulse generator supplied with a high frequency voltage from the source which provides the counting pulses.

Abstract: An electromagnetic, compensating force-measuring or weighing device having at least one working coil movable in an air gap of a magnet system. At least two members for temperature compensation are positioned at different, spaced apart points. The compensating effect of these members on the active part of the system jointly produce a temperature compensating value which is optionally approximately equal to the exact value of the actual temperature curve. The members may be in the form of a plurality of minute particles of nonretentive material having a high negative coefficient of saturation magnetization distributed in the active part. The members may be formed of the afore-mentioned material and be positioned on the active part or be PTC or NTC resistors so positioned.

Abstract: Weighing apparatus of the electromagnetic load compensation type is disclosed including protective shield means for protecting an asymmetrically arranged compensation coil against stray magnetic-flux and particles of contaminants, thereby to improve the accuracy of load measurement.

Abstract: Electromagnetically compensating weighing or dynamometer apparatus in which coil moves out of an equilibrium position relative to a magnet under the influence of a force, including a compensating circuit providing a compensation current proportional to the amplitude of the deflection, an a taring arrangement comprising a store and a digital/analog converter connected to the coil in parallel to the compensation circuit.

Abstract: A balance mechanism for automatically lifting known weights in a single-arm balance comprised of two plates, a first plate supporting the known weights and a pan for an unknown mass to be weighed and a second counterbalancing plate coupled to the first through a box lever having diagonal corners connected to a support member through flexible elements that will permit the box lever to pivot about a diagonal axis in response to a vertical force at one free corner connected to a corner of one balance plate or in response to a vertical force at the other free corner connected to a corner of the other balance plate. One balance plate is secured in space by two taut rectangular loop lines, one line being connected taut to diagonally opposite corners of the plate and to elements affixed to the support member in a position over the free corners of the plate, and the other line being connected taut to the free corners of the plate and to elements affixed to the support member in a position over the other two corners.

Abstract: Improved weighing apparatus of the electromagnetic type is disclosed including linearizing means for controlling the operation of either the compensating means or the indicating means of the system to effect linearization of the load indication over the weighing range, whereby the effect of the compensating coil magnetic field on the main magnetic field of the instrument is eliminated. In the preferred embodiment, smoothing capacitor means are connected with the reference voltage input terminal of the voltage-to-current converter of the constant current source, switch means being operable to control the charging and discharging of the smoothing capacitor means in accordance with the time periods during which compensating current is periodically supplied to the compensating coil means.

Abstract: Weighing apparatus of the electromagnetic load compensation type is disclosed including zero-position detector means for generating a position signal that is a function of the extent to which a loaded weighing pan or the like is displaced from its no-load position, and regulating means responsive to said position signal for generating a compensating current for displacing the weighing pan toward its no-load position, characterized by the provision of filter means connected between the zero-position detector and the regulating means for suppressing the undesired extraneous interference acceleration signals produced, for example, by external shock or vibration forces imparted to the weighing apparatus. In one embodiment, the filter electrical components are constant, and in a second embodiment, means are provided for varying the electrical characteristics of at least some of the filter components as a function of the load applied to the weighing pan.

Abstract: An electromagnetic compensating balance for the measurement of forces having a permanent magnet circuit assembly with an annular enclosed housing and with a central core defining a narrow annular air gap between a portion of the housing and core, and having a movable bobbin concentrically arranged around the core with a coil located in the air gap, the bobbin having end portions projecting above and below the housing which are connected to leaf support members for independent support of the bobbin from the magnet assembly, the upper end portions being connected to a weighing pan for weighing samples.

Abstract: A weighing table is physically connected to the core of a solenoid. The time required for the current flow to build up to a value sufficient to move the core and raise the weight on the table is measured and serves as a measure of such weight. The solenoid is periodically energized through a constant voltage source and correspondingly an associated counter circuit is energized to initiate a time count and when the solenoid is de-energized the counter circuit is reset to zero. The time indicated by the counter circuit is a measure of the weight.

Abstract: A device for converting a constant rotational input into a rotational output which is proportional to a separate input signal characterized by first and second members each having a surface of revolution about an axis with the surface of at least one of the members having an axially changing diameter and the first and second members being mounted for rotation with their surfaces adjacent one another, means for rotating the first member, a transfer device including a pair of rollers mounted for rotation in a plane of rotation for engaging the surfaces of the first and second members and for transmitting rotation of the first member to the second member, the transfer means is connected to a supporting device by a pivot connection having a pivot axis lying in the plane of rotation, and a device for shifting the transfer device along the axis of one of the first and second members to vary the rate of rotation of the second member.

Abstract: A thermobalance wherein fulcra are provided respectively at the tips of both arms in a main balance, auxiliary balances are suspended respectively on said fulcra, one arm of the above mentioned auxiliary balance is extended near to a vertical line passing through the fulcrum of the main balance and a sample and standard sample are suspended on the tips of the respective arms and are arranged in the same furnace.

Abstract: An electromagnetic weighing balance includes a load support system for supporting the mass to be weighed and including an electromagnetic balance coil disposed in a magnetic field and fed with a balance current producing on the support system a force balancing the weight. The magnitude of the current is taken as a measure of the weight. In order to reduce the effect of vibration the balance coil is fed from a high-impedance source and the balance circuit controlling the balance current in response to displacement of the support system from a datum position includes threshold means increasing the high-frequency gain in response to displacements in excess of threshold levels.

Abstract: A self-restoring precision balance which is essentially non-deflecting. Initially, the balance is unbalanced by an amount approximately equal to one half its weighing range, and the electrically energized restoring system is so arranged that a restoring force, is exerted in one direction to maintain the beam at a null condition at loads less than about one half scale, and is exerted in the opposite direction to maintain the beam at a null condition at loads greater than about one half scale. Heating in the restoring transducer is therefore reduced by a factor of 4. A unique arrangement of cross-flexures and a stabilizing band which remains always in tension, is used without affecting the accuracy of the balance, because of the small range of movement of the self-restoring system. A unique two coil electro-magnetic restoring arrangement provides for linearity at low cost.