Joint mechanism for folding ladders, furniture and the like

A joint mechanism comprising:

• a first joint member including
• a disk-shaped portion comprising a pair of opposing, spaced apart disk members,
• a tubular portion extending from said disk-shaped portion and including a pair of opposing, spaced apart sides in each of which is formed a slot,
• a pawl slidably supported in said slots,
• spring means for biasing said pawl in a first direction,
• a pivotable operating lever including a manually actuable handle portion and a pawl-actuating portion engageable with said pawl when said handle portion is actuated, for pushing said pawl opposite said first direction against the bias of said spring,
• a second joint member mounted to said first joint member for relative rotation about an axis of rotation, said second joint member comprising
• a hollow locking disk element including a plurality of circumferentially spaced notches on its outer periphery, said disk element disposed between said disk members and being connected thereto by a pivot pin defining said axis of rotation, said pivot pin extending centrally through said disk element and said disk members such that relative rotation between said disk element and said disk members sequentially orients said pawl in alignment with said notches, said disk element including a plurality of slits situated adjacent respective ones of said notches and extending through said disk element,
• a control member mounted on said disk element and including a plurality of fingers projecting through respective ones of said slits so as to emerge beyond a side of said disk element, each of said fingers including a stop surface and a cammable surface, said stop surface being engageable with said lever when said pawl approaches the associated notch from a first direction, to block movement of said pawl into such notch, said cammable surface being engageable with said lever when said pawl approaches the associated notch from a second direction such that said finger is cammed into its slit to permit the pawl to enter the respective notch, and
• a tubular portion extending from said disk element.