Commercial lifting device—self aligning jack stand

A commercial jack stand for use with a commercial mobile power unit having a pair of parallel lift arms, said jack stand comprising:

• a flat horizontal base plate,
• a first tubular frame attached to said base plate and extending vertically therefrom;
• a second tubular frame positioned in telescoping relationship relative to said first tubular frame and having a vertical series of ratchet teeth on opposite sides thereon;
• a third tubular frame positioned in telescoping relationship relative to said second tubular frame and having a vertical series of ratchet teeth on opposite sides thereon;
• means for vertically aligning the ratchet teeth of said second frame and said third frame relative to said first frame;
• locking means operable for locking said second frame in fixed relation to said first frame while said third frame is being raised, and for locking said third frame in fully extended position to said second frame while said second frame is being raised;
• a pair of ratchet arms, each being pivotally mounted near its mid-portion on opposite sides of said first tubular frame and having a pawl on its upper end extending above said first tubular frame and adjacent to said ratchet teeth and having a ratchet release arm at the lower end thereof, wherein each pawl of said ratchet arms being oriented inward to engage successive ratchet teeth of whichever frame is then being raised for locking that frame in step-wise fashion, and each said pawl being releasable for lowering said second tubular frame and said third tubular frame of the jack stand;
• and
• a rectangular lifting plate attached to the upper end of said third tubular frame and having parallel sides with flanges thereon extending downwardly therefrom, with the lower ends of the flanges having inner surfaces extending outwardly and downwardly at an acute angle for engaging the lift arms of the power unit.