Protective helmet having a chin-strap tightening device

In the case of a protective helmet which is provided with a chin-strap tightening device, to avoid impairment of the protective effect of the protective helmet the tightening device is connected to a band in a manner such that it can be adjusted over the length thereof, the band being anchored at both ends on the helmet shell, being continuous and forming the chin strap. The tightening device essentially comprises a housing, a take-up reel which is accommodated in the latter, is passed through by the chin strap and is spring-loaded in the circumferential direction, as well as a means for the spring-loaded automatic engagement of a locking device between the take-up reel and the tightening device comprising the housing, and, moreover, the tightening device can have a pressure-distribution plate adapted to the throat bulge of the helmet user.