| 摘要 |
<p>A personnel entry means comprising two arcuate shields, a first shield 22c defining an arc of about 180 DEG and a second shield 22b defining an arc in the range of 90 DEG to 180 DEG mounted for rotation concentrically about a common axis to provide sequentially for movement between first, second and third primary positions relative to each other and about an object passing through the perimeter defined by the path of rotation of said shields. <IMAGE></p> |
