| 摘要 |
The present invention provides an adjustable headband for protective headgear with a ratchet mechanism having different resistances. The adjustable headband utilizes a ring gear assembly having a plurality of radially projecting teeth thereon. Each of the projecting teeth of the ring gear assembly has a first tooth side and a second tooth side which is different from the first tooth side. For example, each tooth of the ring gear assembly preferably has a first tooth angle on the first tooth side and a second, different tooth angle on a second tooth side. A spring assembly having at least one spring tooth projecting radially therefrom is connected to the adjustment knob. The spring assembly is positioned such that the at least one spring tooth meshes with the teeth of the ring gear assembly to provide resistance to the rotation of the adjustment knob. Because the first tooth angle of the ring gear assembly is different from and preferably less than the second tooth angle of the ring gear assembly, it is substantially easier to rotate the adjustment knob in the direction of tightening the headband than in the direction of loosening the headband. |
