Method and device for producing a universal joint for supporting claws of the steel roadway support system in mining and tunnelling

摘要

The invention relates to a method and a device for producing a universal joint for supporting claws of the steel roadway support system in mining and tunnelling from a sheet-metal blank with parallel longitudinal edges, preferably convexly curved transverse edges and recesses arranged next to the transverse edges for accommodating a joint pin and also if need be a central recess for separating an eye, accommodating another joint pin, into two bushes, in which method the sheet-metal blank is preheated and is shaped in the preheated state into a hairpin-shaped body in which the joint recesses arranged next to the transverse edges of the blank are arranged in legs bearing against one another and starting from the eye for the other joint pin. According to the invention, provision is made here for the flat blank to be bent in its centre in a shaping movement and for the legs to be subsequently pressed as a result, in the course of which, during the final section of the shaping movement, the leg extensions and the rounded eye portions adjoining them are adapted to the hairpin shape and the eye back is bent free.