Control system for horizontal vehicle-scrubbing brush

Claim 1

In a vehicle-cleaning station, in combination: a portal frame straddling the path of a vehicle to be scrubbed, said frame and said vehicle being relatively movable along said path; a pair of vertical tracks at opposite sides of said frame; a generally cylindrical scrubbing brush having a horizontal shaft with ends respectively guided by said tracks for vertical reciprocation; counterweighted suspension means on said frame engaging said brush and partly balancing the weight thereof; pneumatic hoist means linked with said brush and operable to raise same along said tracks, said hoist means including a piston in a single-acting cylinder and actuating means for the selective admission of air under pressure into said cylinder through an inlet thereof for elevating said brush, said piston having a piston head provided with brake means enabling a controlled descent of said brush under its own weight upon deactivation of said hoist means by a closure of said inlet; and drive means coupled with said shaft for rotating said brush about its axis in a sense causing same to creep up a sloping vehicular surface in contact therewith, in the deactivated state of said hoist means, against a retarding action by said brake means.