Container-lifting spreader with drive for the telescopic movement of spreader's beams protected against damage by collision

A container-lifting spreader comprising locking pins (3,4) that are insertable into seats formed at the corners of a shipping container and upon rotation about their longitudinal axes can be brought in locked engagement with the container, wherein the locking pins are in pairs associated with a common drive (7) effecting simultaneous rotation of the locking pins between locking and unlocking positions, the drive comprising a reversible electric motor (10) and a power transmission that comprises two push rods (6), each of which is in one end hinged to a locking pin (3,4) and in the other end hinged to an operating lever (15) included in the power transmission, and in such way that a driven movement of the operating lever is transferred via the push rods to rotational movements of the locking pins, and further wherein the power transmission comprises an input shaft (18) driven by the motor and having an external thread (19), as well as an output shaft (14) supporting the operating lever and likewise having an external gear ring (20), the said shafts in threaded engagement forming an angle gear, the angle gear providing a self-locking mesh of threads such that rotation of the input shaft (18) causes rotation of the output shaft (14) and the operating lever (15), whereas the opposite is prevented by the self-locking mesh of gears, characterized in that fixed stops (16;

• 17) are arranged to mechanically limit the movement of the operating lever (15) within an angular space (α), the fixed stops this way providing in cooperation with the self-locking angle gear absolute positioning of the locking pins in locking and unlocking rotational positions.