Porte blindée

1,211,528. Shielded cells. COMMISSARIAT A L'ENERGIE ATOMIQUE. 6 May, 1969 [22 May, 1968], No. 23098/69. Heading B4Q. A sliding door 1 for closing a circular passage 3 leading to a cell is shown in its lower closed position in the left-hand half of Fig. 1 and in its raised open position in the right-hand half of the Fig. The door 1 is formed by a thick lead plate 4 having a metal envelope 5 and a flange 7 secured by screws 6. The flange 7 carries guide rollers 9 co-operating with grooves 11 formed in a lead frame 2 having a metal envelope 12. When the door 1 is in the closed position inclined surfaces 15, 16 at the lower end of the door abut surfaces 13, 14 on the frame 2. Sectorshaped lead plates 17, 18 pivoted at 19, 20 to the frame 2 have a flat surface 21 formed by a metal envelope, these plates together with the door and frame forming a shielded extension of the passage 3 when the door is in the open position, the surfaces 15, 16 then abutting the surfaces 21. In a modification (Fig. 3, not shown) the abutting surfaces of the door 1 and plates 17, 18 are of arcuate configuration of the same radius as the passage 3. In other embodiments (Figs. 4-6, not shown) the plates 17, 18 are slidable on the frame 2 to engage and disengage the door 1. In other modifications (Figs. 7, 8, not shown) the pivoted plates 17, 18 are counterbalanced.