The invention relates to a blind rivet nut with pulling mandrel having a rivet tube with a flange, which is provided on its side remote from the flange with an internal thread extending from the end of the rivet tube via a portion of the rivet tube to a clinch zone of the rivet tube which is enlarged by means of a pulling mandrel fitting into the internal thread when the blind rivet nut is set, such that a workpiece receiving the blind rivet nut is clamped by the flange and the enlargement.
A blind rivet nut of this type is known from European Patent Application 158 304. For setting this blind rivet nut a particular pulling mandrel is used which pertains to the setting tool and is provided at its end extending into the internal thread of the blind rivet nut with an external thread fitting into the internal thread of the blind rivet nut and extending over the length thereof so that the pulling mandrel is capable of exerting a pulling force over the length of the internal thread on the rivet tube and of enlarging it in the region of its clinch zone. During the setting of the blind rivet nut, an opposing force is exerted on the flange of the rivet tube by a pressure piece penetrated by the pulling mandrel so that the force acting on the pulling mandrel can act fully on the clinch zone of the rivet tube, the pulling mandrel sliding, as during the setting of a conventional blind rivet, through the pressure piece formed by the setting tool during the setting of a conventional blind rivet. A workpiece, such for example as a sheet metal plate penetrated by the blind rivet nut, is clamped during this setting process so that the set blind rivet nut is therefore riveted. The workpiece is clamped between the flange of the rivet tube on the one hand and the enlargement of the rivet tube on the other hand. After the blind rivet nut has been set, the special pulling mandrel is screwed out of the blind rivet nut so that the blind rivet nut is available for screwing-in of a suitable bolt.
A voluminous prior art exists relating to blind rivet nuts. The embodiment described hereinbefore is to the fore and the same setting process is employed (see European Patent Applications 305868, 264870, U.S. Pat. Nos. 2409352, 3948142, 2565019, 3461771, GB-PS 1205744, DE-OS 3240539).
The object of the invention is to design a blind rivet nut with pulling mandrel so as substantially to simplify the processing thereof.