A ratchet mechanism for a hard hat and method of assembling the same are provided. The ratchet mechanism includes a knob with knob protrusions. The ratchet mechanism also includes a ratchet gear. The ratchet gear includes teeth engagement mechanisms. Each teeth engagement mechanism includes a hooking mechanism and a tooth protrusion. Each hooking mechanism is configured to engage with the knob protrusions. The ratchet mechanism also includes a band housing configured to allow a band to ratchetably move within the housing. The band housing also includes a knob engagement protrusion and a ratchet gear aperture configured with one or more teeth defining a ramped surface. The ratchet gear is disposed on the knob engagement protrusion and includes one or more ratchet gear teeth configured to engage with a set of band teeth on the band, such that the rotation of the ratchet gear tightens or loosens the band during operation.