ANORDNING FOR ATT ALSTRA EN STELLSIGNAL FOR FORFLYTTNING AV EN DYNAMISK MARKFORTETARE

摘要

A first strain gauge fixed to a vibration generator supporting plate, second strain gauges mounted on cross members of a vibrator plate and two accelerometers with vertical recording orientation in a dynamic soil compacting machine provide signals, components of which are added to represent the impact force between the vibrator plate and the soil. Peak values of said added signals are stored in a register. By differentiating the increase in register content a set of pulses from a differentiating element is formed. Either a preset register content or a preset number of pulses is used to trigger the advance motion of the machine and to cancel the register. In a special embodiment the seismic mass of an accelerometer is arranged to form the yoke of an electromagnet the flux of which is adjustable within two limiting values, the first preventing insignificant acceleration from being stored and the second representing the threshold value for triggering.