Adjustment/engagement device in a vehicle seat

An adjustment/engagement device for use in a vehicle seat of the type including a fixed-position frame portion and a movable frame portion which is adjustable between raised and lowered height positions relative to said fixed-position frame portion, said device comprising:

• a stopper bracket fixed to one of said fixed-position or movable frame portions and including a spaced-apart pair of position-determining members which together define plural pairs of engagement grooves which establish said raised and lowered positions of said movable frame portion in addition to establishing at least one intermediate position thereof, and said stopper bracket also including upper and lower engagement pieces formed on upper and lower edge portions, respectively, of said stopper bracket;
• an inverted U-shaped bracket fixed to the other of said fixed-position or movable frame portions in a position so as to oppose said stopper bracket, wherein said U-shaped bracket includes a spaced-apart pair of mounting arms which define a corresponding pair of engagement surfaces;
• lock bracket means jornalled to and extending between said pair of mounting arms and having an engagement portion for selectively engaging with said pairs of engagement grooves to thereby maintain said movable frame portion in one of said raised, intermediate and lowered positions, said lock bracket means being pivotable between an engaged position wherein said engagement portion is engaged with one of said pairs of engagement grooves and a disengaged position wherein said engagement portion is disengaged from said pairs of engagement grooves;
• and
• lock-off bracket means also journalled to and extending between said pair of mounting legs and including means defining a lock-off surface, wherein
• said lock and lock-off bracket means together cooperate to retain said lock bracket means in said disengaged position in response to said lock bracket means contacting said upper engagement piece when said movable frame portion is raised beyond said raised position by virtue of interengagement between said lock bracket means and said lock-off surface thereby permitting free movement of said movable frame from said raised position to said lowered position, and to release said lock bracket means from said interengagement with said lock-off surface in response to said lock-off bracket means contacting said lower engagement piece when said movable frame portion reaches said lowered position, said lock bracket means responsively pivoting into said engaged position upon release of said interengagement with said lock-off surface to thereby cause said engagement portion to engage that one pair of engagement grooves which establishes said lowered position, and wherein
• said pair of engagement surfaces provide means for limiting pivotal movement of said lock means in one direction thereby establishing said engaged position of said lock bracket means by virtue of said lock bracket means coming into bearing contact with said pair of engagement surfaces upon reaching said engaged position and to thus also provide means to establish rigid interconnection between said U-shaped bracket and said support bracket when said engagement portion is engaged with one of said pairs of engagement grooves while yet permitting said lock bracket means to pivot in a second direction, opposite to said one direction, towards said disengaged position when said engagement portion is moved from said one to another of said pairs of engagement grooves upon said movable member being raised towards said raised position.