Portable sandblaster

In portable apparatus to sandblast a worksurface of a particular configuration, the combination of:

• a structure comprising an outer casing from which a sandblasting hood is rigidly supported inside the casing,
• the casing having an outer end opening and the sandblasting hood having an outer end extending through the outer end opening of the casing to provide a projecting open end for application to the worksurface;
• a rotatable sandblasting nozzle in the hood directed towards the end opening thereof;
• means to deliver to the nozzle a stream of grit-laden compressed air;
• a seal carried by the projecting open end of the sandblasting hood, said seal extending beyond said projecting open end and being adapted to make intimate contact with said worksurface and cooperate therewith to isolate the interior of the sandblasting hood chamber from the atmosphere and from the interior of the casing;
• means to withdraw an air stream from the sandblasting hood to entrain particles resulting from the sandblasting operation and to continuously draw atmospheric air into the hood past the seal at high velocity to prevent escape of the grit particles past the seal;
• said withdrawing means operating at a rate to maintain a relatively high vacuum in the sandblasting hood and thus compress said seal against the worksurface with a fluid pressure differential force which, if unopposed, would tend to immobilize the structure relative to the worksurface;
• and
• thrust means carried by said outer casing and extending therefrom for moving contact with the worksurface to divert a sufficient portion of said force from the seal to make the structure readily manually movable along the worksurface.