| 摘要 |
1. A protective helmet structure comprising a swingable visor having lateral tabs, lateral pivot means pivotally mounting said table on opposed sides of the helmet so that the visor is swingable about said pivot means, characterised in that the upper edge of the helmet opening which is able to be closed by the visor, has a projection (5) forming an abutment, in at least a median part thereof, distance (b) between apex of said abutment (5) and axis joining said pivot means (8) about which axis the visor (E) is swingable being a little greater than radius (a) of a circular path travelled through by the median point of the visor on an inner surface of an upper edge portion of the visor. |
