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Publication of BE457637ApublicationCriticalpatent/BE457637A/xx
G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
G03B21/00—Projectors or projection-type viewers; Accessories therefor
G03B21/54—Accessories
G03B21/56—Projection screens
G03B21/58—Projection screens collapsible, e.g. foldable; of variable area
A—HUMAN NECESSITIES
A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
A47L13/00—Implements for cleaning floors, carpets, furniture, walls, or wall coverings
A47L13/02—Scraping
A47L13/04—Scraping with steel wool
A—HUMAN NECESSITIES
A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
A47L13/00—Implements for cleaning floors, carpets, furniture, walls, or wall coverings
A47L13/02—Scraping
A47L13/06—Scraping with wire brushes or wire meshes