US 2889570 A
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Description (OCR text may contain errors)
`lune 9, 1959 J. E. DUFF AIR sUPPoRTED sucTIoN CLEANERS 2 Sheets-Sheet 1 Filed Oct. 15, 1956 June 9, 1959 J. E. DU FF 2,889,570
AIR sUPPoRTEn sUcTIoN CLEANERS Filed oct. 15, 195e 2 sheets-sheen United States Patent O AIR sUProRTED sUcTIoN CLEANERS J ack E. Du, Canton, Ohio, assgnor to The Hoover Company, North Canton, Ohio, a corporation of Ohio Application October 15, 1956, Serial No. 616,053 6 Claims. (Cl. 15-327) The present invention relates to suction cleaners and more particularly to a cleaner of the type which is supported on a cushion of air so that it may be moved about freely with little effort over bare oors as well as over thick carpets.
The present invention is an improvement over the copending application of Curtis C. Coons and John C. Montgomery, Serial No. 418,512, filed March 25, 1954, now U.S. Patent No. 2,780,826 dated Feb. l2, 1957.
In the above-mentioned application a plenum chamber is formed in the base of the cleaner which is open to the supporting surface upon which the cleaner rests and its perimeter encloses a substantial area of the supportlng surface within its confines. The exhaust from the suction fan is led into the plenum chamber to build up an air pressure therein which reacts between the base of the cleaner and the supporting surface to form a supporting cushion of air within the plenum chamber. The area of the supporting surface enclosed within the perimeter of the plenum chamber is so related to the weight of the cleaner and to the quantity of air supplied to the plenum chamber that the cleaner is supported on the cushion of air formed within the plenum chamber with the excess air owing from beneath the edge of the base which forms the plenum chamber.
The cleaner of the above mentioned application operates satisfactorily if the above mentioned relationship between the area of the supporting surface enclosed by the base, the weight of the cleaner and the air supplied to the plenum chamber is adhered to. However, the quantity of air handled by a suction cleaner varies under different conditions of use so the cleaner is floated on air only during normal usage and must be so designed to fulfill the above-mentioned conditions under conditions of normal usage. For example, if the cleaner nozzle is completely blocked so that no air ows through the fan system or is restricted so that little air will flow through the cleaner the cleaner will not be air supported. Additionally, the air support feature places an additional load on the fan system so that it has to be designed to handle that extra load.
According to the present invention a fan independent of the suction creating fan of the cleaner, exhausts into the plenum chamber so that the air support is independent of the operating conditions of the cleaner and the additional load is removed from the suction creating fan of the cleaner.
According to one modification of the present invention the motor cooling fan discharges into the plenum chamber to perform the air supporting function.
According to another modification of the present invention a motor fan unit entirely independent of the suction creating motor fan unit discharges into the plenum chamber to perform the air supporting function.
It is not absolutely essential that an actual plenum chamber be formed in the base of the cleaner but the base could be fiat or only slightly convex and the exhaust air led beneath the base of the cleaner. In that case, a
2 cushionV of air would be formed between the base and the supporting surface and the excess air would flow outwardly from the exhaust port and escape from beneath the periphery of the base.
The present invention is admirably suited to such an arrangement since the fan of the correct capacity could be used with a cleaner of a particular weight and having a particular base area.
Y Other objects and advantages of the present invention will become apparent as the description proceeds when taken in connection with the accompanying drawings in which:
Figure 1 is a vertical sectional view of a suction cleaner showing one modication of the present invention applied thereto.
Figure 2 is a miniature view of the cleaner of Figure 1 showing how it is air supported when in use.
Figure 3 is a view similar to Figure l showing a second modification of the invention applied thereto, and
Figure 4 is a circuit diagram for the cleaner of Figure 3.
Referring to the drawings the reference numeral 10 generally indicates the body or casing of the cleaner of the present invention. The casing 10 is closed by an end cap 11 hinged to the casing 10 at 12 and held closed by a latch 13 of any suitable construction. A spring ring 14 is ysecuredto the underside of cap 11 and engages a supportingring 15 for filter bag `16 and holds it in air tight engagement with a flange 17 extending inwardly from the upper end of casing 10. K
The interior of the casing 10 is divided into a filter chamber 1S and a motor fan chamber 19 by means of a bulkhead 20 which may be secured to the interior wall of the casing 10 in any suitable manner such as by weldmg.
A motor fan unit 21 is mounted within the chamber 19 by means of an annular member 22 which is secured to the interior wall of the casing 10 in any suitable manner such as by welding. The support for the motor fan unit 21 includes vibration damping material 23 as shown.
The motor fan unit 21 includes a multi-stage fan 24 having an inlet opening 25 and exhaust openings 26 which discharge into the chamber 19. The air exhausted into the chamber 19 is exhausted from the casing 10 through ports 27. An annular npstanding perforate member 28 prevents the filter bag 16 from clogging the inlet opening 25.
The motor 30 of the motor fan unit 21 is cooled by a fan 31 which may be of larger capacity than that necessary to provide for the proper cooling of the motor so that the excess capacity maybe used for air supporting the cleaner as will later appear. The fan draws cooling air in through the ports 32 in the motor casing and discharges it throughout outlet port 33 after it has passed through the motor casing to cool the working parts of the motor. l Y
The casing 10 is provided with a supporting base 35 which includes `a plenum chamber 36 separated from the chamber 19 by means of a partition 37. The base 35 and partition 37 are Isecured to the bottom of casing 10 by suitable screws as shown.
An exhaust fitting 38 is secured centrally to the partition 37 and is connected to the exhaust 33 of fan 31 by means of a duct 40 formed by a partition 39 which coacts with the wall of the partition 37 to form the passage 40 leadingV from the exhaust port 33 to the inlet of fitting 38, the outlet of which discharges into the plenum chamber 36. f' -fl`he perimeter of the plenum chamber 36 is formed by an annular downward extending rib 41 which is adapted to rest on the supporting surfaceupon which the cleaner rests andwhich encloses a substantial area of that surface. The air circuits are shown by the arrows in Figure 1.
An inlet fitting 42 is connected centrally to the end cap 11. The fitting 42 is adapted to swivelly and detachably receive an L-shaped fitting 43 which is attached to one end of a flexible and extensible hose 44, to the opposite end of which is attached any suitable cleaning tool 45.
The motor fan unit 21 is the heaviest part of the cleaner and is positioned 'low within the casing 10 so that the cleaner may be towed about by pulling on the hose 44.
The area of the supporting surface enclosed Within the perimeter of the annular rib 41 is so chosen relative to the entire weight of the cleaner and to the capacity of the fan 31 to discharge air into the plenum chamber 36 that a cushion of air is formed Within the plenum chamber which reacts between the supporting surface and the partition 37 to support the cleaner in an upright stable position on a cushion of air as shown in Figure 2.
The fitting 38 is so formed that the cleaner may be laid on its side and the fitting 43 inserted into the fitting 38 for blowing operation.
Operation of Figures 1 and 2 When the motor tan unit 21 is energized and the nozzle 45 `is applied to a surface to be cleaned, dust and dirt loosened at the nozzle 45 will be carried through the hose 44 and fittings 43 and 42 into the interior of the filter 16. The dust and dirt will be deposited upon the interior of the lter 16 and the cleaned air will pass through the lter walls, through ythe openings in the member 28 and into the suction opening 25 of the multi-stage fan 24. Fan 24 will place the air under pressure and discharge it through ports 26 into the chamber 19 from whence the greater portion of it will ow through ports 27 in the wall of the casing to the outside atmosphere.
At the same time, fan 31 will draw a portion of the air discharged into chamber 19 through the ports 32 into the motor casing to cool the working parts of the motor 30 and discharge that air under pressure through the exhaust port 33.
The air under pressure discharged from port 33 will pass through passage 40 and fitting 38 into the plenum chamber 36. The air under pressure discharged into plenum chamber 36 will react between the supporting surface and the wall 37 to support the cleaner in a stable upright position on a cushion of air as shown in Figure 2, the excess air flowing outwardly beneath the rib 41 as shown by the arrows in Figure 2. In this position, the cleaner may be towed about by a slight pull on the hose 44, the resistance to movement of the cleaner across the supporting surface being substantially hictionless because of the cushion of air which supports the cleaner.
The modification in Figure 3 is similar to that of Figures 1 and 2 and where the parts are the Vsame they have been given the same reference characters.
In this modification the casing 50 is divided into a filter chamber 51 and an exhaust chamber 52 by means of a bulkhead 53 welded to the interior wall of the casing 50. The bulkhead S3 resiliently supports the motor fan unit S4 by means of rubber pads 55 as shown. The motor fan unit 54 includes the fan 56 having an air inlet opening 57 and exhausting through the motor casing to cool the working parts of the latter and discharging into the exhaust chamber S2 from which chamber theair exhausts to atmosphere through ports 58.
The base -60 coacts with a partition 61 to form a third chamber 62 in which is positioned an independent motor fan unit 63 mounted on the bottom 64 of base 60 by means of a suitable bracket 65. The motor fan unit 63 includes a fan 66 having a suction inlet 67 and an exhaust port 68 which discharges into a fitting 69 mounted on an upwardly inclined wall 70 extending 'upwardly from the wall 64 and discharging into a plenum chamber 71 formed by wall 64 .and a rib 72 extending downwardly from the base 60. Air inlet openings 73 are provided in the casing 60 for 4theentrance of outside air into the chamber 62.
As in the modification of Figure 1, the center of gravity ofthe cleaner is 'low and the diameter of the base is such that the cleaner may be towed about by pulling on the hose 44.
The area of the supporting surface enclosed within the rib 72 is so related to the total weight of the cleaner and to the quantity of air discharged into the plenum chamber 7i that a cushion of air is built up within the plenum chamber 71 under sufficient pressure to support the cleaner in an upright and stable position on an air cushion with the excess air flowing outwardly beneath the edge of the rib 72 whereby the cleaner may be easily towed about by pulling on the hose 44.
As in the modification of Figure 1, the cleaner may be laid on its side and the fitting 43 inserted into the fitting 69 for blowing operation, it being noted that in each case the blowing operation is performed by a fan other than the main suction fan thus making doubly sure that only clean air is used during blowing operations.
The two motors may be energized simultaneously or selectively. In the former case the cleaner will be air supported only when the cleaner is in operation as in the modication of Figure l. In the latter case, the cleaner may be air supported whether the cleaner is in operation or not and the suction cleaner may be used without being air supported.
The wiring diagram for such an arrangement is shown in Figure 4. The motors 54 and 6 3 may be connected across the line wires by independent circuits 74 and 7S each including a manually actuatable switch 76 and 77, respectively.
Such an arrangement is advantageous under certain conditions when cleaning is being done where it is not desired that the cleaner follow the operator. For example, if the cleaner is setting on top of a stairs and the stairs are being cleaned it would be undesirable to have the cleaner follow the operator down the stairs.
The modification of Figure 3 also has the advantage that the air which forms the air cushion is cool air, unheated by the heat of the motor of the main suction unit.
The motor of the unit 63 is comparatively small and may be cooled in a conventional manner so that only cool air is drawn into the inlet 67 of fan 66.
Operation of Figures 3 and 4 When the motor fan unit 54 is energized dirt laden air will be drawn through the hose 44 and fitting 43 into the filter 16 where the dirt will be separated from the air stream. The cleaned air will then pass through the walls of filter 16 and iiow through inlet opening S7 into the fan 56 where it will be placed under pressure and discharged into chamber 51 after passing through the casing of the motor to cool the working parts of the latter. From the chamber 51 the air is exhausted to atmosphere through ports 58.
If the motor fan unit 63 is also in operation the air from outside the casing 10 will enter chamber 62 through ports v73, flow into the fan 66 through inlet 67 where it will be placed under pressure and be exhausted into plenum chamber 71 through exhaust port 68 and fitting 69. Air under-pressure will be built up within plenum chamber 71 sutlicient to support the cleaner on a cushion of air as inthe modification of Figure 1. The air cushion is formed independently of the main suction fan so that it will not be aiected by variations in the cleaning operations and only cool air unheated by the suction cleaner motor is used in forming the air cushion.
While I have shown and described Ibut two modifications of my invention, it is to be understood that those modifications are to be taken as illustrative only and not in a limiting sense. I do not wish to be limited to the particular structure shown and described but wish to include all equivalent variations thereof except as limited by the scope of the claims.
1. In a suction cleaner including :a casing having an inlet port, suction creating means Within said casing, said casing having a supporting base adapted to encompass a substantial area of the supporting surface upon which the cleaner rests to support the cleaner in a stable position, at least the periphery of said base being normally in contact with the supporting surface when the cleaner is not in use and means for producing a stream of air under pressure independent of that produced by said suction creating means for supplying air under pressure beneath said base, the area of the supporting surface encompassed by said base being so related to the weight of the cleaner and to the quantity of air supplied :beneath said base that the air under pressure reacts between said base and the area of the supporting surface encompassed by said base to form a supporting cushion of air which serves to support the weight of the cleaner.
2. In a suction cleaner according to claim 1 including means for separately energizing said suction creating means and said independent means.
3. In a suction cleaner according to claim 1 in which said independent means is the cooling fan for the motor of said suction creating pressure producing means.
4. In a suction cleaner according to claim 1 including means for independently and selectively energizing said air flow producing means and said independent pressure producing means.
5. In a suction cleaner having a casing including an air inlet port, means in the casing for producing a flow of cleaning air into said casing and for discharging such air to atmosphere, the combination of means for supporting the cleaner in a stable position on a supporting surface and for entrapping air under pressure beneath said supporting means, and means for producing a stream of air under pressure independent of that produced by said air flow producing means for discharging air under pressure beneath said supporting means so as to form an air cushion between said casing and the supporting surface, the area of said air cushion in contact with the supporting surface being so related to the weight of the cleaner and to the quantity of air discharged beneath said supporting means that the pressure of the entrapped air serves to support the Weight of the cleaner.
6. In a suction cleaner according to claim 5 in which said independent pressure producing means is a separate motor fan unit which handles cool air from outside said casing.
References Cited in the file of this patent UNITED STATES PATENTS 1,912,386 Replogle June 6, 1933 2,064,587 Carlstedt Dec. 15, 1936 2,328,184 Becker Aug. 31, 1943 2,743,787 Seck May 1, 1956 2,751,038 Acheson June 19, 1956 2,780,826 Coons et al Feb. 12, 1957 FOREIGN PATENTS 524,095 Germany May 21, 1931 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No., 2,889,570 Julie 9, 1959 Jack Duff It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
Column 5, line 19, before Weense, second oeeurrerleey insert pressure producing up; line El? 'beore "mf-gane neert preseure producing n; line 22, before mea-11e" strike out e pressure producir.
Signed and. sealed this 6th day of Oetober 19590 (SEAL) Attest:
KARL H., XLNE ROBERT C. WATSN Attesting Officer Commissioner of Patents