Chair with a seat-inclination adjusting device

A chair comprising:

• a leg unit;
• a lower frame having opposite front and rear ends, a base plate secured to said leg unit, spaced-apart side plates extending between said front and rear ends in a longitudinal direction, and a latch engaging member that extends upwardly from said base plate and that is formed with a plurality of spaced apart engaging grooves aligned in a first transverse direction relative said longitudinal direction and said base plate;
• a first pivot extending in a second transverse direction relative to said first transverse direction and said longitudinal direction;
• an upper frame including a seat-mounting plate disposed above said lower frame, and two side plates that extend downwardly and respectively from two opposite sides of said seat-mounting plate and that are respectively pivoted to said side plates of said lower frame through said first pivot as to permit pivotal action of said upper frame relative to said lower frame;
• an urging mechanism connected to said seat-mounting plate of said upper frame and said front end of said lower frame so as to resiliently hold said seat-mounting plate in position;
• and an inclination adjusting device including
• a latch mounted slidably on said seat-mounting plate of said upper frame, disposed rearwardly of said latch engaging member, and movable in said longitudinal direction between a first position, in which said latch extends into and engages a selected one of said engaging grooves in said latch engaging member, and a second position, in which said latch disengages said selected one of said engaging grooves in said latch engaging member, and an urging member for urging said latch so as to restore said latch from said first position to said second position;
• said inclination adjusting device includes a retaining box that is fixed to said seat-supporting plate, that is disposed rearwardly of said latch engaging member, and that is formed with a pair of guiding grooves extending in said longitudinal direction, a front receiving chamber that is disposed above and that is in spatial communication with said guiding grooves, and a rear receiving chamber that is disposed rearwardly of and that is in spatial communication with said front receiving chamber, and that extends in said second transverse direction, said latch including a latch plate engaging slidably said guiding grooves, and an abutment plate projecting upwardly from said latch plate in said first transverse direction into said front receiving chamber, said urging member being disposed within said front receiving chamber in such a manner as to urge constantly said abutment plate of said latch for restoring said latch to return from said first position to said second position.