Inclination Adjusting Device for Chair Seat

Abstract

An inclination adjusting device includes an upper seat mounted below a chair seat of a chair. A coupling member is mounted to a rear end of the upper seat and includes a plurality of vertically spaced engaging portions. A lower seat is pivotably mounted to and below the upper seat. An inclination adjusting rod is pivotably mounted to a rod mounting board in the lower seat. An actuating board is connected to the inclination adjusting rod and includes at least one engaging protrusion for releasably and selectively engaging with the vertically spaced engaging portions of the coupling member. The inclination adjusting rod is pivotable between a first position in which the at least one engaging protrusion is engaged with one of the engaging portions of the coupling member and a second position in which the at least one engaging protrusion is disengaged from the engaging portions of the coupling member.

1 . An inclination adjusting device for a chair seat comprising:
 an upper seat adapted to be mounted below a seat of a chair, with a coupling member being mounted to a rear end of the upper seat and including a plurality of vertically spaced engaging portions;   a lower seat pivotably mounted to and below the upper seat, with the lower seat having a bottom adapted to engage with a pneumatic rod for adjusting a height of the lower seat, with the lower seat including a compartment, with a rod mounting board being mounted in an intermediate portion of the compartment, with a height adjusting rod being pivotably mounted to a side of the rod mounting board, with the height adjusting rod being pressable against the pneumatic rod, with an inclination adjusting rod being pivotably mounted to another side of the rod mounting board, with an actuating board being connected to the inclination adjusting rod and including at least one engaging protrusion for releasably and selectively engaging with the plurality of vertically spaced engaging portions of the coupling member of the upper seat; and   a linking member including a front end pivotably connected to a rear portion of the lower base, with the linking member further including an intermediate portion pivotably connected to the coupling member, with the linking member being adapted to engage with a backrest support member;   with the inclination adjusting rod being pivotable between a first position in which said at least one engaging protrusion of the actuating board is engaged with one of the plurality of vertically spaced engaging portions of the coupling member of the upper seat and a second position in which said at least one engaging protrusion of the actuating board is disengaged from the plurality of vertically spaced engaging portions of the coupling member of the upper seat.   
   
   
       2 . The inclination adjusting device for a chair seat as claimed in  claim 1 , with the rod mounting board further including a positioning block fixed thereto, with the positioning block being made of a slightly resilient material and including two inclined abutting faces on a bottom side thereof, with the inclined abutting faces meeting at a top, with the inclination adjusting rod bearing against and being retained by one of the inclined abutting faces corresponding to one of the first and second positions. 
   
   
       3 . The inclination adjusting device for a chair seat as claimed in  claim 1 , further including, in combination: a tension spring having two ends respectively attached to the inclination adjusting rod and the actuating board, with the tension spring biasing the inclination adjusting rod toward the first position when the tension spring is in tension. 
   
   
       4 . The inclination adjusting device for a chair seat as claimed in  claim 1 , further including, in combination: a support mounted in a rear portion of the compartment and having an upper face, two blocks mounted on two sides of the upper face of the support, a cover plate mounted on top of the blocks, defining a space between the cover plate and the blocks for slideably receiving a rear section of the actuating board; and a compression spring mounted around a front section of the actuating board, with the compression spring having two ends respectively attached to the actuating board and the inclination adjusting rod, and with the compression spring being compressed when the actuating board is pivoted rearward, thereby biasing said at least one engaging protrusion of the actuating board to engage with one of the plurality of vertically spaced engaging portions of the coupling member of the upper seat. 
   
   
       5 . The inclination adjusting device for a chair seat as claimed in  claim 1 , with said at least one engaging protrusion including two engaging protrusions respectively on two sides of a rear end of the actuating board, with the engaging protrusions being adapted for sharing shear force acting on the actuating board when a user is lying against a backrest of the chair.