| 摘要 |
A pair of elongate holding devices ( 7 a , 7 c) extending along opposite sides of an imaginary rectangle have respective longitudinal recesses ( 12, 21 ) which hold respective edge portions ( 6 a , 6 c) of a poster ( 6 ). One holding device ( 7 c) has a fixed bearing member ( 16 ) and a movable member ( 18 ) which contains the recess ( 21 ) and which is pivotable about a pivot axis ( 19 ) from an active position, in which the recess ( 21 ) is open in a direction away from the opposite holding device so that the poster ( 6 ) tums back on itself near the edge portion ( 6 c), the poster being under tension between the pair of holding devices, to a passive position, in which tension in the poster is released sufficiently to allow the edge portion ( 6 c) to be removed from the recess ( 21 ). The holding device ( 7 a) is preferably an upper holding device with an undercut slot ( 12 ) slidably receiving a bead ( 14 ) at the upper edge portion ( 6 a) of the poster. The movable member ( 18 ) has wings cooperating with cylindrical bearing surfaces on the fixed bearing member ( 16 ) to ensure that no excessive local stress is applied to the holding device ( 7 c).
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