| 摘要 |
PURPOSE:To manually move a bed in no relation to rotation of a screw shaft, by constituting a nut to be capable of optionally spreadably opening and releasing engagement screwing of this nut screwed to said screw shaft. CONSTITUTION:When manual quick movement of a ceiling plate 1 is desired in no relation to the rotation of a screw shaft 2, an intermediate part 15a of a link 15 is pulled in the direction of an arrow head (a), and a lever 11 is driven in the direction of an arrow head (b). In this way, pins 12, 13 are moved downward, in consequence nut supporting metal fittings 6, 7, that is, left and right nut parts 5a, 5b of a nut 5 are spreadably opened as shown by arrow heads (c), (d) in the drawing. Accordingly, screwing of the nut 5 is released from the shaft 5, and the nut 5 is placed in a condition perfectly free from the shaft 2, then the plate 1 can be quickly moved through push-pull operation by hand in no relation to the rotation of the shaft 2. |
