Angle adjusting/positioning device for a backrest of a chair

Abstract

An angle adjusting/positioning device includes first and second sleeves fixed to a backrest and a seat of a chair. The first sleeve has a first axle hole and a first toothed portion. A second sleeve includes a second axle hole, a second toothed portion, and a positioning portion. A third sleeve has a third axle hole and an actuating portion. An axle extends through the first, second, and third axle holes. A handle fixed to the third sleeve is operable to move the actuating portion relative to the positioning portion, causing the second toothed portion to engage with or disengage from the first toothed portion. An angular position of the backrest relative to the seat is adjustable when the second toothed portion disengages from the first toothed portion. The angular position of the backrest is fixed when the second toothed portion engages with the first toothed portion.

1 . An angle adjusting/positioning device for a backrest of a chair, with the angle adjusting/positioning device comprising:
 a first mounting seat adapted to be fixed to one of a backrest and a seat of a chair, with the first mounting seat including a first sleeve having a first axle hole, with the first sleeve including an end face having a first toothed portion;   a second mounting base adapted to be fixed to another of the backrest and the seat of the chair, with the second mounting base including a second sleeve having a first side and a second side opposite to the first side, with a second axle hole extending from the first side through the second side of the second sleeve, with a second toothed portion provided on the first side of the second sleeve and surrounding the second axle hole, with the second sleeve further including a positioning portion;   an elastic element mounted between the first and second sleeves, with the elastic element biasing the first and second toothed portions of the first and second sleeves to disengage from each other or engage with each other;   a handle mechanism including a handle seat having a third sleeve, with a handle fixed to the third sleeve, with the third sleeve including a third axle hole and an actuating portion; and   an axle extending through the third axle hole, the second axle hole, and the first axle hole of the handle seat, the second sleeve, and the first sleeve, with the handle operable to move the actuating portion relative to the positioning portion, causing the second toothed portion to engage with or disengage from the first toothed portion, with an angular position of the backrest relative to the seat being adjustable when the second toothed portion disengages from the first toothed portion, with the angular position of the backrest being fixed when the second toothed portion engages with the first toothed portion.   
     
     
         2 . The angle adjusting/positioning device as claimed in  claim 1 , with the positioning portion formed on the second side of the second sleeve, with the positioning portion including first and second positioning grooves each having a bottom wall, with a spacing between the bottom wall of the first positioning groove to the second side of the second sleeve being different from a spacing between the bottom wall of the second positioning groove to the second side of the second sleeve. 
     
     
         3 . The angle adjusting/positioning device as claimed in  claim 2 , with the spacing between the bottom wall of the first positioning groove to the second side of the second sleeve being larger than the spacing between the bottom wall of the second positioning groove to the second side of the second sleeve, with an inclined surface extending between the first positioning groove and the second positioning groove. 
     
     
         4 . The angle adjusting/positioning device as claimed in  claim 3 , with the actuating portion of the handle seat including a receiving groove receiving the positioning portion, with the receiving groove including a wall having a positioning member, with the positioning member selectively engaged in one of the first and second positioning grooves to engage the second toothed portion with the first toothed portion or to disengage the second toothed portion from the first toothed portion. 
     
     
         5 . The angle adjusting/positioning device as claimed in  claim 1 , with the first axle hole including a first compartment in the end face of the first sleeve, with the second axle hole including a second compartment in the first side, with the elastic element received in the first and second compartments. 
     
     
         6 . The angle adjusting/positioning device as claimed in  claim 5 , with the first sleeve of the first mounting base including a first tab on an outer periphery thereof, with the first tab adapted to be engaged with a lower end of the backrest, with the second sleeve of the second mounting base including a second tab on an outer periphery thereof, with the second tab adapted to be engaged with a rear end of the armrest, with the third sleeve of the handle seat including a third tab on an outer periphery thereof, with the handle fixed to the third tab. 
     
     
         7 . The angle adjusting/positioning device as claimed in  claim 6 , with the chair including a guiding rod having a lower end connected to the base and an upper end connected to a front end of the armrest, with the seat including a side having a receiving portion, with the guiding rod received in the receiving portion, with the lower end of the backrest including a first receptacle receiving the first tab, with the rear end of the backrest including a second receptacle receiving the second tab.