| 摘要 |
The invention relates to a welding helmet meant to protect the welder's face during the electric arc or oxyacetylene welding operation. According to the invention, the protection helmet consists of a shield (1) which can be lifted or lowered and which is attached to the welder's head by means of an adjustable elastic clamp (18) having a support (15) mounted thereon. The welder can lift or lower the shield (1) by chin-pressing a button (9) mounted on a lever (6) which, if rotated, moves a whole mobile assembly inside the helmet, said assembly consisting of an elastic frame (2) having the face piece (1) mounted therein and which is blocked at both ends of the stroke by means of a bistable tilting mechanism provided with a cam (10). By pressing the button (9), the mobile assembly is lowered to the bottom end (b) of the frame (2) which is beak-shaped and has the role of ratchet following the trajectory (A) tangent to cam (10) and is blocked by means of a stopper (11). In order to lift the shield (1), the button is further pressed until the beak (b) passes into a zone (c) of the cam (10) and then moves towards right until it meets a shoulder (d) of the stopper. If the button (9) is released, the beak (b) slides on the right side of cam (11), being pulled by a helical spring (13) until the lever (6) is blocked in the stopper (11).
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