Abstract: An apparatus for abrasive cleaning comprising a truck adapted to run on the surface to be cleaned and at least one abrasive cleaner supported by a supporting mechanism on the truck and limitedly movable toward or away from the surface, the abrasive cleaner having an abrasive cleaning tool at its lower end, said or each abrasive cleaner being supported by the supporting mechanism so as to be limitedly tiltable in every direction with respect to an axis approximately perpendicular to the surface, the supporting mechanism being provided with a compression spring for biasing the abrasive cleaner away from the surface. Even when the surface to be cleaned has an undulation, the abrasive cleaner tilts with respect to the axis to hold the cleaning tool in uniform contact with the surface and assure a stable and uniform cleaning operation.

Abstract: An abrasive cleaning apparatus comprising a truck adapted to run on the first surface to be cleaned, a first abrasive cleaner adapted to be pressed against the first surface and mounted on the truck by a first support assembly so as to be limitedly movable in the direction of a first axis substantially perpendicular to the first surface and and limitedly tiltable in every direction with respect to the first axis, and a second abrasive cleaner adapted to be pressed against the second surface to be cleaned and substantially perpendicular to the first surface and mounted on the truck by a second support assembly so as to be limitedly movable in the direction of a second axis substantially parallel to the first surface and to be limitedly tiltable in every direction with respect to the second axis.

Abstract: An air motor includes an arrangement such that a part of an exhaust air from a cylinder of the air motor passes through a gear chamber containing a gear mechanism which links a gear fixed to a shaft directly connected to a rotor with a power output shaft and is discharged through a silencer.