1. Field of the Invention
The present invention relates to a protective mask, especially to a protective mask in which a hoop is adjusted to become tighter or looser for fitting user's head circumference. Moreover, a mask body of the protective mask can be rotated and lifted to a certain angle for meeting requirements of various users.
2. Description of Related Art
Generally, an industrial safety mask includes a lens for faces protection of users. For example, a welding safety mask is used to protect users from bright light and sparks generated during the welding process. The design of the safety mask includes a lens and a mask body, both being arranged with through holes one two sides thereof. By screws inserted into the through holes, the lens and the mask body are pivoted and connected to each other. When users intend to lift the lens, the screws on two sides are loosened and the lens is adjusted to the position required. Then the screws on two sides are threaded and tightened. The repeated steps of rotating to loosen, adjustment and threading to tighten cause inconvenience in use. Moreover, users may lift or pull the mask down without proper operation and the screws are not correctly placed. Thus the lens already lifted may fall down sometimes.
Moreover, most of safety masks are with fixed size. Thus for users whose head size is larger or smaller, the only way to have a tight fit is by means of a fastener underneath the chin. Thus the safety mask will not fall off from user's head. This leads to discomfort of wearing. After wearing for a long period of time, users may feel uncomfortable on cheek and chin area. Therefore, there is room for improvement.