Abstract: The invention pertains to a method of quality grading in uniformity tests of rotors, in particular automobile tires, where a force and/or geometric variation function obtained in a measuring run from the rotating rotor is analyzed by comparison with limit values, with the root-mean-square value or the arithmetic mean of the variation function being used for such comparison with limit values.

Abstract: A method and an apparatus for determination of run-out of a rotating body, especially an automobile tire, without the need for mechanically contacting the rotating body. The apparatus includes a device for rotating the body, a scanning system with a transmitter for transmitting parallel rays directed toward the rotating body, a receiver to receive the residual rays not blocked by the rotating body, and an analyzer circuit for determination of variations in blockage on the basis of which run-out of the rotating body is determined.

Abstract: A method and apparatus for controlling the quality of tires, in particular automobile tires, in which a rotating tire rolls on a rolling surface of a test drum and where one force-measuring system measures the dynamic force portions and another force-measuring system measures the static force portions of the forces exerted by the rotating tire in the same flux of forces through the rolling surface of the test drum which is supported on the same bearing element of a bearing unit.

Abstract: Apparatus and method for testing the nonuniformity of rotating bodies, and especially motor vehicle tires, in which the rotating body is pressed against a test drum and the radial and lateral reaction forces are measured at several locations on the drum. At each location a value proportional to the radial force is added to the lateral force to correct for the inductive disturbance of the lateral force measurement caused by the radial force. The corrected lateral force can then be used to determine the cone and angle effect.

Abstract: A method and apparatus for testing the uniformity of a rotary body whereby an electrical analysis signal is produced by travel measuring or force measuring transducers having an amplitude which varies as a function of the non-uniformities, multiplied by a direct current signal which varies as a function of the speed of rotation of the body to produce a further signal which is then integrated to provide the Fourier coefficients of the Fourier development series of the analysis signal.

Abstract: An electrical circuit for digitally displaying an input electrical signal to minimize fluctuations in the output and maximize the speed of response to changes in the input signal whereby the input signal is applied to a first low pass filter and a second low pass filter having both a lower threshold frequency and a slower response time to changes in the input signal than the first filter. The outputs of the two filters are applied to a differential amplifier to produce a differential signal which is applied via a pair of serially and oppositely connected Zener diodes to the output of the second filter, which is also connected to the digital display, to cause rapid response to signal changes. The frequency of a unijunction oscillator is also controlled by the differential signal to increase the measuring rate of the digital display whenever the input signal charges by more than a predetermined value.