DESCENDING SPEED CONTROL SYSTEM OF SLING AND PILING CRANE

摘要

Disclosed are a descending speed control system of sling and a piling crane provided with the descending speed control system of sling. The descending speed control system of sling comprises a distance detecting device (1) and a controller (2). A displacement signal output end of the distance detecting device (1) is connected to a distance signal receiving end of the controller (2), and a control signal output end of the controller (2) is connected to a control end of a gantry descending proportional valve (3). The distance detecting device (1) detects the vertical distance S between the lower end of the sling (12) and the upper surface of a container (11), and sends a distance signal. The controller (2) receives the distance signal, and calculates the maximum allowable opening a2 of the gantry descending proportional valve (3) based on a formula of a2=g(s), and controls the actual opening of the gantry descending electric proportional valve not to be greater than the maximum allowable opening a2.