Folding bleacher and operator therefor

Claim 1

IN A POWER OPERATOR FOR FOLDING BLEACHERS, A FRAME, A PAIR OF LATERALLY SPACED PROPELLING WHEELS INDEPENDENTLY ROTATABLE ON THE FRAME ABOUT A COMMON AXIS, A HANDLE ON THE FRAME FOR MANIPULATING THE OPERATOR, A RELATIVELY LARGE SPROKET SECURED ON EACH WHEEL, A DOUBLE CHAIN ON EACH SPROCKET INCLUDING A FIRST STRAND COMPLETLY ENCIRCLING THE SPROCKET TIGHTLY FOR ROTATION THEREWITH AND A SECOND PARALLEL FREE STRAND SECURED TO THE FIRST ADJACENT THERETO ON THE SIDE THEREOF TOWARD THE OTHER DOUBLE CHAIN, A MOTOR SUPPORT PIVOTED ON THE FRAME BETWEEN THE WHEELS FOR MOVEMENT ABOUT AN AXIS PARALLEL TO THE WHEEL AXIS, A DRIVE MOTOR ON THE MOTOR SUPPORT HAVING A DOUBLE ENDED DRIVE SHAFT, A RELATIVELY SMALL DRIVE SPROCKET ON EACH END OF THE DRIVE SHAFT POSITIONED RESPECTIVELY WITHIN THE PERIPHERIES OF SAID SECOND STRANDS AND ENGAGEABLE THEREWITH, MEANS FOR PIVOTING THE MOTOR SUPPORT TO MESH THE DRIVE SPROCKETS WITH THE SECOND STRANDS TO DRIVE THE WHEELS SYNCHRONOUSLY OR TO DISENGAGE THE DRIVE SPROCKETS FROM THE SECOND STRANDS TO PERMIT INDEPENDENT DIFFERENTIAL MOVEMENT OF THE WHEELS, AND MEANS FOR COUPLING THE FRAME TO A FOLDING BLEACHER.