Portable hand-held, manually-operated duster

Claim 1

A portable hand-held manually operated duster for propelling a controlled stream of pulverulent material comprising: a housing providing a material hopper and impeller and drive chambers, said impeller and drive chambers being positioned in substantially vertical planes in the normal position of use of the duster; said housing providing an interior wall for said drive chamber having a normal position of use in a substantially vertical plane; a side-mounted, vertically disposed closure plate for said drive chamber; a manually engageable crank having a shaft journalled for rotation on said plate; a gear train in said drive chamber connected to said crank and composed of a plurality of molded plastic enmeshed speed multiplication gears and terminating in a high speed driven gear disposed at the normally lower end of said gear train and including a pair of intermediate gears connected for joint rotation about a common axis, one of said intermediate gears being enmeshed with and driving said high speed driven gear; said interior wall and plate providing bearings on said axis; a metallic shaft supporting said intermediate gears and journalled in said bearings; an impeller mounted for rotation in said impeller chamber; a molded plastic shaft supporting and fixed for rotation with said high speed gear and extending through said interior wall and connected to said impeller; said plate providing a bearing supporting one end of said last-named shaft; a Teflon bearing mounted in said interior wall and journalling said last-named shaft; and said housing being formed with an air inlet opening adjacent the base of said drive chamber; and said plate being formed with a bearing journalling said crank shaft at the normally upper end of said gear train, said plate being formed with a plurality of discharge openings disposed in circumferentially spaced relation around said bearing adjacent the upper end of said drive chamber and providing air discharge passages extending from said drive chamber to the atmosphere for inducing a flow of air cooling said gear train and freeing said drive chamber from pulverulent material entering therein.