Conveniently adjustable seat backrest structure

Abstract

An adjustable seat backrest structure, including a support, an adjusting component, and backrest plates; an adjusting groove extending along an up-down direction is formed at a middle part of the support; a front side of the adjusting component is connected to the backrest plates; an adjusting part is arranged on a rear side of the adjusting component; a left end and a right end of the adjusting part engage with a left side edge and a right side edge of the adjusting groove respectively so that the adjusting part is slidable up and down in the adjusting groove and being capable to be fixed at any position with respect to the adjusting groove, but not capable of moving front and back with respect to the adjusting groove.

What is claimed is: 
     
         1 . An adjustable seat backrest structure, comprising:
 a support, an adjusting component, and backrest plates;   an adjusting groove extending along an up-down direction is formed at a middle part of the support;   a front side of the adjusting component is connected to the backrest plates;   an adjusting part is arranged on a rear side of the adjusting component;   a left end and a right end of the adjusting part engage with a left side edge and a right side edge of the adjusting groove respectively so that the adjusting part is slidable up and down in the adjusting groove and being capable to be fixed at any position with respect to the adjusting groove, but not capable of moving front and back with respect to the adjusting groove.   
     
     
         2 . The adjustable seat backrest structure of  claim 1 , wherein a rotary knob is arranged on a back surface of the adjusting part; two press blocks are arranged on a left side and a right side of the rotary knob respectively; rotation of the rotary knob is capable of driving the two press blocks to slide at the left end and the right end of the adjusting part so as to removably press against the left side edge and the right side edge of the adjusting groove respectively. 
     
     
         3 . The adjustable seat backrest structure of  claim 2 , wherein two clamping grooves penetrating up and down through the adjusting part are arranged at the left end and the right end of the adjusting part respectively; the left side edge and the right side edge of the adjusting groove are fitted into the clamping grooves respectively to limit the adjusting part to move front and back with respect to the adjusting groove and to allow the adjusting part to slide up and down in the adjusting groove by allowing sliding of the left side edge and the right side edge of the adjusting groove in the clamping grooves as the adjusting part slides up and down in the adjusting groove. 
     
     
         4 . The adjustable seat backrest structure of  claim 3 , wherein the adjusting part comprises an adjusting main body and an adjusting back shell; the adjusting back shell covers on a rear side of the adjusting main body; the two clamping grooves are formed between a left side of the adjusting back shell and the rear side of the adjusting main body and between a right side of the adjusting back shell and the rear side of the adjusting main body respectively. 
     
     
         5 . The adjustable seat backrest structure of  claim 2 , wherein the two press blocks are slidably assembled on the left end and the right end of the adjusting part respectively; two press parts are formed at outer ends of the two press blocks respectively; the press parts removably abut against the left side edge and the right side edge of the adjusting groove respectively; two arc-shaped convex surfaces are formed at inner ends of the two press blocks respectively;
 the rotary knob is rotatably mounted at the adjusting part, and a rotary knob main body of the rotary knob is located between the inner ends of the two press blocks; two driver parts are arranged on an outer circumference of the rotary knob main body spaced apart from each other by 180 degrees; each of the driver parts comprises a convex part and a concave part distributed adjacently along a circumferential direction of the rotary knob main body;   two press blocks are connected to each other by a tension spring; the tension spring provides an elastic force to enable the inner ends of the two press blocks to abut against the driver parts respectively;   when the rotary knob rotates to enable the convex parts of the two driver parts to simultaneously abut against the arc-shaped convex surfaces of the two press blocks, the press parts of the press blocks press against the left side edge and the right side edge of the adjusting groove; when the rotary knob rotates to enable the concave parts of the two driver parts to simultaneously abut against the arc-shaped convex surfaces of the two press blocks, the press parts of the two press blocks do not press against the left side edge and the right side edge of the adjusting groove.   
     
     
         6 . The adjustable seat backrest structure of  claim 5 , wherein the adjusting part comprises an adjusting main body and an adjusting back shell; the adjusting back shell covers on a rear side of the adjusting main body; a mounting chamber is arranged between the adjusting back shell and the adjusting main body;
 the rotary knob main body of the rotary knob is rotatably mounted at a middle part of the mounting chamber, and a rotating handle exposed from a rear side of the adjusting back shell is arranged on a rear side of the rotary knob main body; the two press blocks are mounted in two sliding grooves on a left side and a right side of the mounting chamber respectively; the tension spring is located in front of the rotary knob, and two ends of the tension spring are connected to two hook parts protruding towards front sides of the two press blocks respectively.   
     
     
         7 . The adjustable seat backrest structure of  claim 6 , wherein rotating grooves are formed in the mounting chamber on the rear side of the adjusting main body; rotating parts are formed at a middle part of a front side of the rotary knob main body, and the rotating parts are rotatably inserted into the rotating grooves respectively;
 two limiting plates spaced apart from each other by 180 degrees are arranged on outer circumferential side walls of the rotating grooves respectively; two limiting grooves spaced apart from each other by 180 degrees are formed on a circumferential area surrounding outer peripheries of the rotating parts of the rotary knob main body; the two limiting plates are located within the two limiting grooves respectively;   when each of the limiting plates abuts against a first end of a corresponding limiting groove, the convex parts of the driver parts abut against the two press blocks; when each of the limiting plates abuts against a second end of the corresponding limiting groove, the concave parts of the driver parts abut against the two press blocks.   
     
     
         8 . The adjustable seat backrest structure of  claim 2 , wherein a vertically extending teethed portion is arranged on each of the left side edge and the right side edge of the adjusting groove, and the teethed portion is engagable with an outer end of a corresponding press block. 
     
     
         9 . The adjustable seat backrest structure of  claim 1 , wherein the support is a frame, and a middle part of the frame is provided with the adjusting groove; the support is configured to be integrally connected with a seat or detachably attached to the seat. 
     
     
         10 . The adjustable seat backrest structure of  claim 1 , wherein two connecting parts are arranged on the front side of the adjusting component;
 the backrest plates are detachably connected with the two connecting parts respectively through elastic cantilevers;   a connecting chamber is provided inside each of the two connecting parts; an inserting groove communicating with an external environment is formed on one side of the connecting chamber;   a front end of a corresponding elastic cantilever is connected with a corresponding backrest plate; an inserting piece is arranged at a rear end of the corresponding elastic cantilever; the inserting piece is removably inserted into and detachably fixed in the inserting groove.   
     
     
         11 . The adjustable seat backrest structure of  claim 10 , wherein a rotatable pressing plate is mounted inside the connecting chamber; one end of the pressing plate is a locking hook part; the locking hook part is located within the connecting chamber; another end of the pressing plate is a pressing part; the pressing part protrudes out of the connecting chamber; the pressing part is connected to a spring; the spring provides an elastic force to push the pressing part to bias the locking hook part to pivot at a position where the locking hook part fixes the inserting piece. 
     
     
         12 . The adjustable seat backrest structure of  claim 11 , wherein the inserting piece is provided with an inserting hole; a locking block protrudes from the locking hook part; the locking block is removably inserted into the inserting hole of the inserting piece inserted into the inserting groove. 
     
     
         13 . The adjustable seat backrest structure of  claim 11 , wherein a quantity of the backrest plates is two, and the two backrest plates are arranged side by side in a left-right direction; the two connecting parts are also arranged side by side in the left-right direction corresponding to the two backrest plates;
 the two connecting parts are arranged to a left side and to a right side of the adjusting part respectively and positioned in front of the adjusting part;   each of the two connecting parts comprises a connecting main body and a connecting front cover; the connecting front cover is closed on a front side of the connecting main body; the connecting chamber is defined between the connecting front cover and the connecting main body.   
     
     
         14 . The adjustable seat backrest structure of  claim 13 , wherein the connecting front cover of any one of the two connecting parts is closed at an outer side of the connecting main body of said any one of the two connecting parts which is a side far away from the connecting main body of another one of the two connecting parts; a spring groove is formed inside the connecting main body; the pressing part of the pressing plate is located on a front side yet spaced apart from said front side of the spring groove; the spring is mounted to the spring groove, and two ends of the spring abut against a bottom of the spring groove and a rear side of the pressing part respectively. 
     
     
         15 . The adjustable seat backrest structure of  claim 12 , wherein a rotating shaft is arranged between the locking hook part and the pressing part of the pressing plate, and the rotating shaft is rotatably mounted within the connecting chamber; an inclined surface is formed on a side of the locking block facing an opening of the inserting groove. 
     
     
         16 . The adjustable seat backrest structure of  claim 10 , wherein each of the elastic cantilevers  5  is an elastic sheet. 
     
     
         17 . The adjustable seat backrest structure of  claim 1 , wherein each of the backrest plates comprises a frame plate and a flexible back cushion; a rear side of the frame plate is connected to the front side of the adjusting component; the flexible back cushion is detachably fixed on a front side of the frame plate. 
     
     
         18 . The adjustable seat backrest structure of  claim 17 , wherein connecting holes are formed around the frame plate; upper and lower parts of the flexible back cushion are embedded with connecting pieces; connecting columns extending out of a rear side of the flexible back cushion are arranged on a left side and a right side of each of the connecting pieces, and each of the connecting columns is detachably inserted into a corresponding connecting hole. 
     
     
         19 . The adjustable seat backrest structure of  claim 17 , wherein each of the backrest plates is provided with a vibrating motor; the frame plate has a concaved middle part, and a plurality of through holes are formed on the frame plate; the vibrating motor is fixed to a rear side of the flexible back cushion and is located within one of the through holes of the frame plate.