Lower-back supporting structure for a bed or a chair

Abstract

A lower-back supporting structure for a bed or a chair includes a sliding base, two scissor lifts, a driver and a supporting member. The sliding base has a pair of slide slots and a pair of rotating pins, a securing portion between the two rotating pins, and a plurality of the locking apertures. Two scissor lifts both have an X-shaped frame having a pivot. A driver has a positioning end, an extendable rod, a through hole and a sliding rod placed through the slide slot, the through hole and the first front cotter holes. A supporting member has a pair of slide tracks and a pair of rotating holes. The driver drives the sliding rod along the slide slot of the sliding base to shorten the extendable rod, the scissor lifts rotate around the pivots to lift such that the supporting member is pushed away from the sliding base.

1 . A lower-back supporting structure for a bed or a chair comprising:
 a sliding base forming a rectangular frame, front ends and rear ends of two length-wise sides respectively having a pair of slide slots and a pair of rotating pins, a securing portion disposed on a down-extended portion between the two rotating pins, and the sliding base including a plurality of the locking apertures;   two scissor lifts both forming an X-shaped frame having a pivot, two bottom ends of each having a first front cotter hole and a rear cotter hole, two top ends of each having a second front cotter hole and rear rotating pin, the first front cotter hole of each scissor lift aligned with the slide slot of the sliding base, the rear cotter hole of each scissor lift pivoted to the rotating pin, and a sliding pin is placed through the two second front cotter holes of the two scissor lifts;   a driver having a positioning end, the positioning end pivoted to the securing portion of the sliding base, another end of the driver having an extendable rod and a through hole disposed at an end of the extendable rod, the through hole aligned with the slide slot of the sliding base; and a sliding rod is placed through the slide slot, the through hole and the first front cotter holes; and   a supporting member having four corners corresponding to the four top ends of the two scissor lifts, a pair of slide tracks and a pair of rotating holes, each slide track corresponding to the sliding pin, and each rotating hole pivoted to the rear rotating pins;   wherein the driver drives the sliding rod along the slide slot of the sliding base to shorten the extendable rod, the scissor lifts rotate around the pivots to lift such that the supporting member is pushed away from the sliding base.   
     
     
         2 . The lower-back supporting structure for a bed or a chair as claimed in  claim 1 , wherein the slide slot is an elongate slot having an inner arcuate region and an outer arcuate region at two respective ends. 
     
     
         3 . The lower-back supporting structure for a bed or a chair as claimed in  claim 1 , wherein the securing portion of the sliding base and the positioning end of the driver are pivoted together. 
     
     
         4 . The lower-back supporting structure for a bed or a chair as claimed in  claim 1 , wherein the driver is an electric motor. 
     
     
         5 . The lower-back supporting structure for a bed or a chair as claimed in  claim 1 , wherein the driver is a hydraulic device. 
     
     
         6 . The lower-back supporting structure for a bed or a chair as claimed in  claim 1 , wherein a first spacer tube and a first pair of washers are jacketed on the sliding pin between the two slide tracks of the supporting member. 
     
     
         7 . The lower-back supporting structure for a bed or a chair as claimed in  claim 1 , wherein at least two second spacer tubes and a second pair of washers are jacketed on the sliding rod among the slide slot, the through hole and the first front cotter hole. 
     
     
         8 . The lower-back supporting structure for a bed or a chair as claimed in  claim 1 , wherein a soft padding is disposed on the supporting member.