Self-propelled scaffold

Claim 1

A SELF-PROPELLED SCAFFOLD COMPRISING, IN COMBINATION: (A) FRAME MEANS ADAPTED TO STAND IN A NORMALLY UPRIGHT POSITION; (B) A NORMALLY HORIZONTAL PLATFORM SUPPORTED ON SAID FRAME MEANS; (C) TWO REAR WHEELS ROTATABLE ON SAID FRAME MEANS IN NORMALLY UPRIGHT PLANES SPACED FROM EACH OTHER; (D) TWO FRONT LEGS ON SAID FRAME MEANS; (E) A STEERING COLUMN MOUNTED ON SAID FRAME MEANS FOR ANGULAR MOVEMENT ABOUT A NORMALLY UPRIGHT AXIS; (F) HANDLE MEANS ACCESSIBLE FROM SAID PLATFORM FOR MANUALLY ACTUATING SAID ANGULAR MOVEMENT; (G) TWO WHEELS MOUNTED ON SAID STEERING COLUMN FOR ROTATION IN RESPECTIVE, SPACED, NORMALLY UPRIGHT PLANES; (H) AUTOMATIC BRAKE MEANS ASSOCIATED WITH EACH OF SAID FRONT WHEELS FOR SELECTIVELY ARRESTING ROTATION OF THE ASSOCIATED FRONT WHEEL IN A PREDETERMINED DIRECTION; AND (I) SHIFTING MEANS FOR SHIFTING SAID FRONT WHEELS RELATIVE TO SAID FRONT LEGS BETWEEN A FIRST NORMAL POSITION IN WHICH SAID FRONT AND REAR WHEELS ARE ADAPTED TO ENGAGE A SUPPORTING SURFACE WHILE SAID FRONT LEGS ARE UPWARDLY SPACED FROM SAID SURFACE, AND A SECOND NORMAL POSITION IN WHICH SAID FRONT LEGS AND REAR WHEELS ARE ADAPTED TO ENGAGE SAID SURFACE, (1) SAID SHIFTING MEANS INCLUDING A SHIFTING LINKAGE MOVABLY MOUNTED ON SAID FRAME AND ACCESSIBLE FROM SAID PLATFORM, SAID LINKAGE OPERATIVELY CONNECTING SAID FRONT LEGS AND SAID FRONT WHEELS FOR MOVEMENT RELATIVE TO EACH OTHER.