| 摘要 |
<p>A protection shield, e.g. a welders mask, has an only slightly transparent screen (5) such as a welder's glass movable in front of and away from an opening (2) in the shield by a reversible electric motor (15), driving the screen directly. The screen is guided by rods (6a, 6b) in the shield, which it engages in only a few discrete points (7, 8). Motor, screen and guides are easily removable from and insertable into the shield. This gives a simple and reliable structure with low energy requirement. There are provisions for charging a battery (27) energizing the motor (15) either by solar cells (40) or by an external source. A hand operated switch (31) is provided with means (33) to be carried on a finger of the user, which switch operates the screen. A spatter glass (4) is taken up in the shield in guides (3) so as to be easily removable and replaceable and so that its thickness is not critical.</p> |
