Abstract: The invention relates to a mechanism in a bin-dumping device for gripping portable bins, to empty them into a truck for collecting waste, particularly household garbage, the gripping mechanism comprising a chassis connected to the dumping device and having at its upper part one or several shaped sections, particularly in the shape of a comb, adapted to be engaged under a collar provided at the upper end of the frontal wall of the body of the bin. It comprises, at the lower part of the chassis (1), at least one support devices (7) adapted to come into contact with the frontal face (5) of the bin (4), preferably at its lower half, said one or more devices being controllable for being applied forcefully to the bin during at least part of its path of displacement, during the operation of the dumping device.