| 摘要 |
The actuator being linked to a mechanism for pivotally actuating the headrest and footrest of the frame bedstead comprises an extender tube (5) whose front dead end linking to a pivoting lever and whose rear open end being inserted with a nut having threads, an actuator rod (7) whose front part being threaded and received in the tube (5) through threading with the nut and whose rear end having a turn handle (22), and an outer casing tube (6) receiving the tube (5) being keyed with a key (16) on the tube (6) in the slit (12) of the tube (5). When the handle (22) is turned, the tube (5) screwed out forward juided by the key to actuate the pivoting lever until reaching the maximum limit of keying where the key comes off the slit to allow the idle rotation of the tube with the rod (7) for no more advancement of the tube (5) from turning the handle. In reverse, the tube (5) contracts rearward to the limit to come off the key and idly rotate with the rod. The idle rotation produces no excessive application of force to the damage.
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