Patent GB-1049292-A (GB)
Title: Improvements relating to vacuum cleaners
IPC: A47L9/14
Filed: 1964-02-21
Abstract: 1, 049, 292. Air filters. TOKYO DENKI KABUSHIKI KAISHA. Feb. 21, 1964 [Feb. 23, 1963 (6); Feb. 25, 1963; Sept. 9, 1963 (2); Dec. 28, 1963], No. 7350/64. Heading B1T. The dust filtering receptacle of a vacuum cleaner is formed from an air-permeable, synthetic resin foam material, i.g. polyurethane or polystyrene foam, adapted to control and collect fine dust particles within its pores during operation and capable of being reconditioned by simple washing to remove the fine dust particles. In the embodiment shown in Fig. 11, the dust filtering receptacle is formed as a cylindrical receptacle 18 mounted between an inner receptacle 17 of relatively coarse mesh and an outer receptacle 19 of relatively fine mesh. Coarseweave fabrics of natural or synthetic fibres, perforated or porous synthetic resins or metals, and coarse metal wire mesh are suitable materials for the receptacle 17 while the receptacle 19 may be of fabric such as velveteen. During the operation of the cleaner, air containing waste material and dust is forced through an intake port 4 in the front cover 5 by means of a motor-driven fan 3 and into the hollow interior of the receptacle 17 where coarse particles are arrested while the fine dust particles pass through into the receptacle 18. Any dust particles which may pass through the receptacle 18 are arrested by the receptacle 19. The dust-free air leaves through a discharge port 6 in the main housing 1. One means of mounting the dust-retaining receptacles 17, 18 and 19 in the housing 1 is shown in Fig. 18, the receptacle 17 being provided at its open end with a flange 49 and the receptacle 19 with a packing 11 overlapping the flange 49, the packing 11 and flange 49 being supported between the housing 1 and the front cover 5. The receptacles 17 and 18, or all three receptacles 17, 18 and 19, may be bonded together by gluing or welding. In another embodiment, a single dust receptacle is used, this being made solely of airpermeable, synthetic resin foam material, and it may be for example of the same form as the receptacle 18 of Fig. 11. The internal surface of the receptacle may be corrugated or ribbed, or may be provided with undulations in the form of protruding mounts. An auxiliary filter piece consisting of a strip of the same material as the receptacle wound into a spiral may be disposed within the receptacle against its closed end. The strip may have corrugations on one or both of its surfaces. In still another embodiment, the dust receptacle consists of cup-shaped inner and outer members, each of an air-permeable, synthetic resin foam material, and at least the outer member is provided with a corrugated surface so that a continuous air gap, or discontinuous air gaps, are formed between the facing surfaces of the members. In a modification of this embodiment, the dust receptacle consists of three layers, the intermediate layer being relatively thin and air gaps being formed on both sides of this layer. In a further embodiment, the filtering member consists of a side wall of an air-tight material and a thick base member of an air-permeable, synthetic resin foam material. A suitable material for the side wall is vinyl film. The principles of the invention can also be applied to vacuum cleaners of the socalled tank type (also known as the pot type) as illustrated in Fig. 12 (not shown) in which the filtering element is dish-shaped.