Abstract: Method and apparatus for providing an indication of compaction in vibration compacting machines. A signal proportional to acceleration occuring when the working part of a vibrating compaction machine strikes soil is developed by means of an acceleration pick-up and is compared with a stepped sequence of potentials representative of preselected acceleration values. During consecutive observation intervals it is observed which of these potentials are exceeded and which are not exceeded by the maximum acceleration occuring in an observation interval. In one embodiment, a control signal is developed which provides an indication of the compaction. The control signal is used to change the preselected acceleration values dependent upon the degree of compaction. Another embodiment of the invention develops a signal which is used to change the distance between the preselected acceleration values independent of the control signal.

Abstract: A vibration roller comprises a power limiting device (20) engaging the travelling lever (3), the vibration roller having a prime mover (1), a hydrostatic pump for the travelling drive, which hydrostatic pump is driven by the prime mover and arranged to be controlled by a travelling lever (3), and a vibration drive driven by the prime mover. The power limiting device comprises a stepped piston (27) slidingly movable in a stepped bore (24). The fluid pressure in the travelling drive and in the vibration drive engage the steps thereof. The stepped piston (27) is movable into the setting range of the travelling lever (3), by the sum of the fluid pressures, such that the maximum deflection of the travelling lever is limited to values, at which the total power consumption of the vibration roller does not exceed the limiting power of the prime mover.