| 摘要 |
A chair backrest elevating device includes a slide base having a slide way provided with a recessed hole and a positioning rod. An adjusting unit is combined with the positioning rod, composed of a sustaining member, a movable block, a spring, a positioning block and an elastic retainer. A fixing plate unit received in the slide way of the slide base contains a fitting block and a fixing plate. A slide cover is coupled with the slide base for covering the adjusting unit and the fixing plate unit. The slide base and the slide cover are assembled on a chair backrest while the fixing plate unit is combined with a seat. When the backrest is pulled up or down, the slide base and the slide cover is also shifted to have the sustaining member engaged in different-level engage grooves of the fitting block, thus adjusting the backrest upward or downward.
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