Patent GB-770760-A (GB)
Title: Improvements relating to suction cleaners
IPC: A47L9/14
Filed: 1954-12-30
Abstract: 770,760. Suction cleaners. HOOVER, Ltd. Dec. 30, 1954 [Jan. 7, 1954; Jan. 7, 1954; Sept. 22, 1954], No. 37723/54. Classes 8(1) and 8(2) A suction cleaner including a motor fan unit and a filter and having co-operating sealing surfaces afforded by parts of the filter and the cleaner respectively for producing a seal between the filter and the inlet is characterized by means operated by the pressure difference produced by the fan for pressing the said surfaces into sealing contact. In one embodiment, Fig. 4, applied to a canister type cleaner, a filter bag 44 is held along two edges (not shown.), against a sealing block 34 by means secured to an end cap 26. The end of the filter 44 lies closely adjacent an inner plate 29 of the end cap 26 and is provided with a suction inlet 51. A sealing member 64 is interposed between the end of the filter 44 and the plate 29 and the end of the filter is pressed into contact with the sealing member 64 by the difference in pressure existing within the filter 44 and that ap- ,plied through openings 63 in the plate 29 communicating through ports 62 with the exterior of the filter where a lower pressure exists. In order to close the openings 62, 63 when no filter 44 is within the cleaner, a spring plate 65 is provided on the plate 29 and carries a feeler 68 which engages the filter 44 when inserted to hold the member 65 clear of the openings. In a further embodiment, Fig. 11, the corners of the filter are held by means of spring loaded plungers 146 on an end cap 124 having an inner plate 127 and an annular web 128 surrounding an inlet 130, forming a chamber which is connected to the atmosphere through a port 137. A sealing member 132 surrounding inlet 130 and engageable with the end of the filter is connected by a diaphragm 133 to the plate 127 whereby atmospheric pressure presses the sealing member 132 into engagement with the filter. Tn a further embodiment Fig. 18, the filter 220<SP>1</SP> is held between a pilot member 225<SP>1</SP> and one side of a distensible wall 252.subjected to atmospheric pressure through an opening 253; the interior of the pilot member 225' is subjected to the pressure within the filter through a port 255 and this pressure is transmitted to the filter adjacent the wall 252 through openings 254 whereby the atmospheric pressure will cause the wall 252 to force the filter into engagement with the pilot member 225<SP>1</SP>. In a modification of this embodiment the chamber is subjected to pressure existing on the outlet side of the fan. In a further modification atmospheric pressure acting through the holes 254 cause a sealing band secured to the pilot member to engage-the filter and force it into contact with a rigid member on the cleaner. In a further embodiment the invention is applied to a handle propelled type cleaner. In one form, Fig. 21, a filter bag 346 having an inner sleeve 354 is passed over a member secured to the outlet 340 of the cleaner and which member includes a distensible member 355 which is expanded by the outlet pressure into sealing engagement with the inner sleeve 354. In a modification of this embodiment a distensible chamber is supplied with pressure from the outlet connection and is thereby forced into engagement with the filter. In a further modification a flexible sleeve is connected to the outlet of the cleaner at one end while the other end is surrounded by the inner sleeve of the filter. The flexible sleeve is distensible by the pressure of the outlet into sealing engagement with the filter. Specifications 770,758 and 770,759 are referred to.