Abstract: Means to control imbalance of an eccentric mass connected to a rotating shaft in a shaker housing wherein the eccentric mass is adjacent to but is not fixedly connected to the shaft, wherein a first end of the mass is connected to a mass moving means which can move one end of the mass to a plurality of different distances from the rotating shaft, and is able to hold that end of the mass at each of these distances during rotation; wherein a second end of the mass is restrained from centrifugal movement during rotation of the shaft.

Abstract: An apparatus for measuring and recording accelerations or other physical quantities experienced by easily damaged items of commerce such as fruit and electronic computers. A triaxial accelerometer or other suitable sensor produces signals which are sampled by a microprocessor operating according to a program stored in a read-only memory. When the sampled accelerations or other physical quantities exceed a predetermined threshold, samples are stored in a random access memory, along with their times of occurrence. The apparatus provides a serial port for reading out the recorded acceleration data. The data may then be subjected to further processing externally.