'Retromatic' automatic device for keeping the values of the working angle and height of the bucket constant regardless of the position of the oscillating arm of a hydraulic digger

摘要

Automatic device for keeping the values of the working angle (alpha) and height H of the bucket constant regardless of the position of the oscillating arm (1) of a hydraulic digger. The invention consists of a sensor (C1) converting the variation in length of the oscillating arm thrust cylinder rod (V1) into a voltage UC1. This voltage, through the use of function generators (GF2) and (GF3) in conjunction with servo-amplifier cards (CSA2) and (CSA3) is converted into two voltages U2 and U3 which, by virtue of the servodistributors (SD2) and (SD3), modify the length of the bucket thrust cylinder rod (V3) and of the jib thrust cylinder rod (V2). The device according to the invention is particularly intended for digging earth from trenches and ditches with the aid of a hydraulic digger. IMAGE