Abstract: An electronic weighing apparatus is provided, including a self-contained calibration weight module that is operated by a motor to alternately connect and disconnect, respectively, a calibration weight relative to the vertically-displaceable parallelogram-guided load receiving member of the scale. The calibration weight is normally suspended in an inoperable condition by means of a pair of internally threaded sleeves rotatably supported in the cover portion of the housing of the calibration weight module. A motor is operable to rotate the sleeves and thereby lower lifting screws threadably connected therewith, whereby the calibration weight is lowered toward a supported position between and in engagement with a pair of parallel carrier arms that extend horizontally from the load receiver.

Abstract: A vessel holding device is composed of a sheet metal strip which is bent to form a polygon. The resulting side wall members are provided with bores or recesses for holding the vessels, such as, test tubes or syringe cylinders in a predetermined manner. The vessel holding device can be used standing on one of the side wall members or on the upper or lower edges of the device.

Abstract: A weighing apparatus comprising a first self-contained weighing device (1) including a first farme (2), a first load-receiving member (5) connected by a parallel guide arrangement for movement from a normal no-load position relative to the first frame, a load-responsive device (10) for indicating the magnitude of an applied load as a function of the movement of the first load receiving member, and a first motion-transmitting lever (7) connected between the first load receiving member and the position-responsive device, characterized by the provision of a second load receiving member (16,28) to which the load to be measured is applied, and a second pivotally mounted motion-transmitting lever (17,30) connecting the second load receiving member, thereby to provide a resultant load range that is higher than that of the first weighing device. Thus, various increased load ranges may be achieved starting from a standard self-contained weighing apparatus.

Abstract: A draft protection device for a precision balance including an exposed weighing dish. The device includes at least two hollow bodies of similar shape which can be telescopically slid one into the other. The hollow bodies are maintained in the desired position by a self-locking intermediate ring placed on the inner second hollow body.

Abstract: A coupling for transmitting a rotary motion in both directions of rotation. The coupling includes a drive shaft and a driven shaft and has a freewheeling capability in both directions of rotation for rotary motions introduced into the driven shaft. One or more balls are guided in a circular groove having an asymmetrical cross-section. The balls rest against a clamping disk having a non-circular cross-section. When the drive shaft is rotated, the balls are pressed against and clamped by a guide surface of the driven shaft.

Abstract: Weighing apparatus of the load compensation type includes a source of constant current pulses the duration of which is determined by a regulating signal in response to the position of the load receiver relative to the frame, thereby to maintain the load receiver in an initial or zero position during the application thereto of a load to be measured. The regulating circuit includes a PID regulating amplifier that produces a differential signal (D) and a proportional and integral signal (PI). The PI signal controls the operation of a switch that determines the duration of the constant current pulses, and the D signal modulates the amplitude of the constant current from which the pulses are formed. In this manner of using the differential regulating signal component (D), the influence of various deleterious effects on the weighing apparatus, such as vibration, is avoided.

Abstract: The apparatus which preferably is designed as a scale or balance comprises a circuit which can execute certain function sequences in succession independent of one another by means of function selecting keys. The circuit comprises a matrix which stores a sequence of functions determined by previously run operations and automatically suggests the sequence to the operator by activating or displaying at least one function key corresponding to this determined sequence. A control key is provided, furthermore, in order to interrupt the automatically suggested sequence at any time and to allow the selection of an arbitrary function from the complete scope of functions.

Abstract: A weighing system including a weighing cell (1) which supplies a measurement signal (I) to an A/D converter (3) via a signal line (2). An interference signal (i), superposed on the measurement signal, is decoupled out of signal line (2) at the signal output of the weighing cell (1), rotated by means of an inverter (4) in terms of phase by 180.degree., and again coupled into the signal line (2) at the signal input of the A/D converter. An ohmic resistance (RO) is connected in series in the signal line (2) between the uncoupling node (AK) and the in-coupling node (EK). The interference signal (i) is decoupled preferably capacitively via a series circuit that forms the frequency-determining member of the active low-pass filter including a condenser (C) and an ohmic resistance (R1). On the other hand, a galvanic coupling (R3) is provided for the recoupling of the interference signal (-i).

Abstract: An electronic balance includes a measuring cell for electromagnetic load compensation. The measuring cell and a load receiving member of the balance are arranged in an inner housing which is closed to all sides with the exception of an opening for a receiving cone of the load receiving member. The inner housing is mounted in the balance housing so as to be spaced apart from the walls, the base and the cover of the balance housing. A circumferentially extending partition wall is tightly sealingly attached to the bottom and the cover of the balance housing. The partition wall is mounted between the inner housing and the walls of the balance housing.

Abstract: In a new method for the titrimetric determination of the contents in a chemical solution, wherein a quantity of a reaction component, corresponding in each case to the change of a certain physical-chemical magnitude or a value derived from that, is added to a reaction component and this added quantity is so regulated that it will be a function of the prior and/or predetermined magnitude change or changes and the already added total quantity of one of the reaction components. In the method mentioned, the minimum quantity added is not allowed to fall below a predetermined percentage, e.g., 1.0 percent, or even 0.5 to 0.1 percent, of the already added quantity. The apparatus for performing the method therefore contains devices operable to regulate the quantity to be added as a function of the magnitude change and the already added total quantity of one of the reaction components. Potentiometric titration is the most important area of application of the new determination method.

Abstract: The calibration process is initialized as a function of the past measurement results. The time to the next calibration is dependent on the quality of the calibrations in the past. Before the calibrating of the balance, the program checks a number of parameters, which can affect the weighing result and compares the results with predetermined limits. If set conditions are exceeded, the program in each case returns to the beginning and starts anew.

Abstract: The invention relates to a circuit and a method adapted for measuring and digitizing the value of a resistance. The circuit includes and A/D converter operating in accordance with a charge balancing principle, and a resistance network connected to the A/D converter so that the resistance is both a component of the A/D converter and of the resistance network. The A/D converter and the resistance network are interconnected in such a manner so as to permit only a purely resistive measurement. A processor is connected to the A/D converter for obtaining a composite measured resistance value from a plurality of individual measured resistance values. The method according to the invention permits accurate (or precise) resistance measurements having a high degree of resolution of an order of magnitude of 10.sup.5 points. The method is applicable in particular for temperature measurements, for examples in calorimeters or in precision scales, but also in other resistance measurements.

Abstract: The method of measuring positions is based on tracking an interference pattern which is generated when line grids is different line densities are superimposed. According to the present method the line grid of an optical scale is projected onto a line grid formed by a plurality of adjacently arranged diodes, whereby digital switching elements are allocated to the photodiodes and are integrated with same on a common substrate and which compare pair-wise the intensities of adjacent diodes. An absolute measuring of positions proceeds by an additional coding of the line grid of the scale. The method has use in linear as well as curvilinear (angular) measuring of positions.

Abstract: The moving housing parts of an analytical balance are couplable with drive apparatus, which receives the appropriate control commands for opening or closing, for instance, from sensors operating in a contactless fashion. Proximity sensors or voice control sensors can be utilized as sensors. The mechanical process of the opening-or closing movement occurs by means of a drive housed in the housing.

Abstract: An apparatus for depositing of reference weights in an electronic scale consisting of two levers swivelable around vertical axes, one end of each lever is always in contact with a cam disc attached on a vertically disposed shaft and the other end of which is developed as a gliding shoe which may be pushed below the lifting tray. By rotating the cam shaft, the lifting trays cause the reference weights to be deposited by the cam discs at first each individually one after the other and then jointly onto the carriers.

Abstract: A temperature sensor includes an elongated support of a material having good thermal conductivity. The temperature sensor element is pressed against the support by a spring element, in order to measure the temperature of the support. A mean temperature value can be determined, as a result of the substantial length of the support and the particular horizontal disposition thereof with respect to the heating element.

Abstract: A weighing apparatus is provided with a wind shielding arrangement for protectively enclosing a load-receiving scale member. A plurality of symmetrical curvilinear concave transparent shell-like wind shield sections of unequal diameters of generation are concentrically mounted on the scale housing above the load-receiving pan for relative rotational movement about a common axis between a closed protective condition, and an open condition affording access to the scale pan. In one embodiment, a pair of shield sections have generally coplanar edge portions mounted in a pair of concentric circular grooves, respectively, contained in a support on the upper surface of the housing adjacent the load receiving member. The inner shield section is retained in its associated groove by a resilient annular retainer ring that extends radially outwardly above a radially inwardly extending lip portion on the lower edge of the inner shield section.

Abstract: Weighing apparatus of the electromagnetic load compensation type includes an improved variable (C.sub.x) and reference (C.sub.o) capacitance comparison arrangement for sensing the position of the movable load receiver member relative to the stationary base member. The comparison arrangement supplies an error signal that is proportional to the capacity ratio, which error is used to control a compensation current (i.sub.L) that is supplied to a compensation coil to maintain the movable load receiver member at its initial zero position. The variable capacitance is produced by a variable air capacitor including a first pair of stationary capacitor plate electrodes (10, 12), and a movable plate-like metal shield or screen which extends partially between the first pair of electrodes in accordance with movement of the load receiver member.The position sensor arrangement is simple to construct and install, and affords precise measurement during use.