Patent ID: 7448470

Claim:
A maintenance stand comprising: a horizontally elongated wheeled base frame having a front end, a rear end and laterally opposite sides, a horizontally elongated upper worker platform assembly including an upper platform support frame in parallel relation to said base frame, first and second laterally spaced double scissors linkages interconnected between said base frame and said upper platform support frame, each of said double scissors linkages being adjustable between a low collapsed position and a vertically extended position and each including a laterally outer lower arm, a laterally inner lower arm pivotally connected at its midpoint to a midpoint of said laterally outer lower arm on a first laterally extending horizontal axis, a laterally outer upper arm, a laterally inner upper arm pivotally connected at its midpoint to a midpoint of said laterally outer upper arm on a second laterally extending horizontal axis, first corresponding ends of said laterally inner lower arms being pivotally connected to said base frame on a third laterally extending horizontal axis, and transverse braces between said laterally inner lower arms and said laterally inner upper arms, first corresponding ends of said laterally inner upper arms being pivotally connected to said upper platform support frame on a fourth laterally extending horizontal axis, second corresponding ends of said laterally inner lower arms being pivotally connected, respectively, to second corresponding ends of said laterally inner upper arms on a fifth laterally extending horizontal axis, first corresponding ends of said laterally outer lower arms being pivotally connected, respectively, to first corresponding ends of said laterally outer upper arms on a sixth laterally extending horizontal axis, a first pair of track and follower connections between said base frame and second corresponding ends of said laterally outer lower arms, a second pair of track and follower connections between said upper platform support frame and second corresponding ends of said laterally outer upper arms, an intermediate platform pivotally connected to said second corresponding ends of said laterally inner lower arms and to said second corresponding ends of said laterally inner upper arms on said fifth laterally extending horizontal axis, a first self leveling step stairway interconnected between said upper platform support frame and said intermediate platform, a second self leveling step stairway interconnected between said base frame and said intermediate platform, and power means operable to move said double scissors linkages between said low collapsed position and said vertically extended position.