US3729275A

US3729275A - Vacuum cleaner

Info

Publication number: US3729275A
Application number: US00123568A
Authority: US
Inventors: D Furnell
Original assignee: Electrolux AB
Current assignee: Electrolux AB
Priority date: 1970-03-26
Filing date: 1971-03-12
Publication date: 1973-04-24
Anticipated expiration: 1990-04-24
Also published as: CA938757A; GB1311523A

Abstract

A vacuum cleaner has a casing which is disposed about and envelops at least one end of an electric motor and a fan driven by the motor. The fan includes a disk having a first set of blades at one side, such blades projecting axially in a first direction from the motor toward an air inlet. The motor housing and casing define a space for flowing dust-laden air in a path of flow from the inlet at the one side of the disk to an outlet axially removed therefrom and at the other side of the disk. A gap is formed between the fan disk and the end of the motor housing adjacent to which the fan is located. The blades of the first set at the air inlet effect flow of dust-laden air radially outward at the one side of the disk, and, after reaching its periphery, such air continues to flow axially toward the outlet. A second set of blades is provided at the other side of the disk, such blades projecting axially in a second opposite direction toward the motor. The blades of the second set function to maintain the gap between the disk and motor housing substantially free of dust accompanying air flowing through the space to the outlet from the periphery of the disk.

Description

ilnited States Patent [191 Furnell [451 Apr. 24, 1973 VACUUM CLEANER [75] Inventor: Dennis Leslie Furnell, Hemel Hempstead, England [73] Assignee: Aktiebolaget Electrolux, Stockholm,

Sweden [22] Filed: Mar. 12, 1971 [21] App]. No.: 123,568

Primary Examiner-William L. Freeh Attorney-Edmund A. Fenander [57] ABSTRACT A vacuum cleaner has a casing which is disposed about and envelops at least one end of an electric motor and a fan driven by the motor. The fan includes a disk having a first set of blades at one side, such blades projecting axially in a first direction from the motor toward an air inlet. The motor housing and casing define a space for flowing dust-laden air in a path of flow from the inlet at the one side of the disk to an outlet axially removed therefrom and at the other side of the disk. A gap is formed between the fan disk and the end of the motor housing adjacent to which the fan is located.

The blades of the first set at the air inlet effect flow of dust-laden air radially outward at the one side of the disk, and, after reaching'its periphery, such air continues to flow axially toward the outlet. A second set of blades is provided at the other side of the disk, such blades projecting axially in a second opposite direction toward the motor. The blades of the second set function to maintain the gap between the disk and motor housing substantially free ofdust accompanying air flowing through the space to the outlet from the periphery of the disk.

10 Claims, 3 Drawing Figures 2 Sheets-Sheet 1 FIG 2 Patented April 24, 1973 2 Sheets-Sheet 2 BACKGROUND OF THE INVENTION 1. Field of the Invention My invention relates to a vacuum cleaner of the kind having a casing movable over a surface to be cleaned and an elongated and upstanding handle pivotally connected to the casing. In a vacuum cleaner of this kind the casing is disposed about and envelops a motor-fan unit which draws in air and dust through a suction inlet at the bottom of the casing and discharges the air and dust from the casing to a dust collector.

2. Description of the Prior Art In known vacuum cleaners of this kind heretofore provided the casing is disposed about and envelops at least one end of the motor and a fan driven by the motor. The fan includes a disk which is fixed to and rotatable with the motor shaft adjacent to one end of the motor housing. The side of the disk facing the end of the motor housing is substantially smooth and free from projections. The opposite side of the disk is provided with a set of blades or vanes projecting axially in a direction from the motor housing toward an air inlet.

The motor housing and easing define a space for flowing dust-laden air in a path of flow from the inlet at the bladed side of the disk to an outlet in communication with a dust collector, the outlet being axially removed from the inlet and at the smooth side of the disk. A gap is formed between the end of the motor housing and the smooth side of the disk. The fan blades effect flow of dust-laden air radially outward at the bladed side of the disk to its periphery at which region the air is deflected by the casing and then flows axially toward the outlet.

In vacuum cleaners of the kind just described dustladen air passes into the gap between the end of the motor housing and the smooth side of the disk with the result that dust collects in the gap. When a sufficient quantity of dust accumulates in the gap, especially at the vicinities of the motor and fan bearings, the motor and fan become sluggish in operation. The quantity of dust collecting and accumulating in the gap eventually can clog the motor and fan bearings and overload the motor sufficiently to stop it which in turn can overheat the motor if it is not promptly disconnected from the source of electrical supply under such adverse operating conditions.

SUMMARY OF THE INVENTION It is an object of my invention to provide an improvement in a vacuum cleaner for maintaining a gap between a fan disk and motor housing substantially free of dust accompanying air flowing past the gap in its path of flow from an inlet to an outlet of a space defined in part by the motor housing.

In accord with the invention I accomplish this by providing a first set of blades or vanes at one side of a fan disk which projects axially in a first direction from the motor toward the air inlet. These blades or vanes effect flow of dust-laden air radially outward at the one side of the disk, and, after reaching its periphery, such air is deflected and flows axially toward theoutlet.

A second set of blades or vanes is provided at the other side of the disk, such blades projecting axially in a second opposite direction toward the motor housing across the gap between the disk and housing. The

blades of the second set function to maintain the gap substantially free of dust accompanying air flowing axially through the space to the outlet after being deflected at the periphery of the disk.

BRIEF DESCRIPTION OF THE DRAWING cleaner illustrated in FIG. 1, taken at line 2-2 of FIG.

3, to illustrate details more clearly; and

FIG. 3 is a fragmentary vertical sectional view taken at line 33 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, the vacuum cleaner 10 embodying my invention includes a base 11 movable over a surface to be cleaned with the aid ofa pair of wheels (not shown) at the rear thereof and a smooth bottom portion 12 which glides over the surface. The base 1 l is manipulated over the surface by an upstanding handle 14 pivotally connected at its lower end to the base at the rear thereof in any suitable manner (not shown). Within the base lll are disposed a motor-fan unit 15 and a rotatable roller 16 having bristles l7 distributed along its length.

The motor-fan unit 15 comprises a motor 18 and a fan 19. The shaft 20 of the motor 18 is journaled in bearings at the ends of the motor housing 21, the lower one of which is shown at 22 in FIG. 3. To the shaft'20 is fixed the hub 19a of the fan 19. An endless belt 23 is disposed about an annular groove 19b in the hub 19a and a portion of the roller 16.

A casing 24, which forms a part of the base 11, is disposed about the motor 18 and envelops at least the lower end thereof, as seen in FIG. 3. The cross-sectional area of the casing 24 is greater than that of the motor housing 21 and includes an axially extending side wall 24a, a bottom transverse wall 24b having a central opening 25 through which the fan hub 19a extends, and a top transverse wall 240 which extends radially inward from the side wall 24a and is united at its inner end, at 26, to the side wall of the motor housing 21.

Air and dust are drawn into the bottom of the base 11 through a suction inlet 27' at the bottom 12. The central opening 25 in the transverse wall 24b serves as an air inlet through which dust-laden air passes from the bottom of the base 11 into the interior of the casing 24. The casing 24 and motor housing 21 define a passageway or space 27 into which dust-laden air passes through the air inlet 25 and from which such air is discharged through an outlet 28 provided in the side wall 24a. The portion of the motor housing 21 coacting with the casing 24 to define the passageway 27 is imperforate.

A dust collector 29 is detachably connected at 30 to the casing 24 at the outlet 28. The dust collector 29 may be a cloth bag which is permeable to air and through which air, from which dust and dirt have been removed within the bag, can pass. As seen in FIG. 1, the bag 29 extends upward alongside the handle 14 and its upper end is supported on the handle by an elongated helical spring 30.

The fan 19 is of the centrifugal type and includes the hub 19a and a disk 19c fixed thereto which is of dishlike form. Thedisk 19c, which has its convex side 19d facing the bottom transverse wall 24b, has a diameter approaching and slightly less than the diameter of the casing 24, as seen in FIG. 3, to provide a gap 31 between the side wall 24a of the casing 24 and the peripheral edge of the disk 19c. A plurality of fan blades 192 are fixed to the convex side 19d of the disk 19c and extend radially outward to the periphery thereof from its axis of rotation. The fan blades l9e, which may be referred to as a first set of blades, are distributed on the disk 19c and project axially of the motor shaft 20 from. the convex side 19:! thereof toward the inlet 25. The blades l9e, upon rotation of the fan 19, induce flow of'dust-laden air through the space 27 from the inlet to the outlet 28. i

In accordance with my invention, in order to main tain the gap 32 between the motor housing 21 and the concave side 19f of the disk 19:: substantially free of dust accompanying air flowing through the space 27 from the inlet 25 to the outlet 28, a plurality of blades 19g are fixed to the concave side of the disk. The blades 19g extend radially outward from first regions 33 to second regions 34 of the disk 190, the second regions 34 of the blades 19g being nearer to the periphery of the disk 190 than the first regions 33 thereof. Further, the blades 19g, which may be referred to as a second set of blades, are distributed on the disk 19c and are parallel to the shaft '20 and project axially thereof from the concave side l9fthereof toward the lower end of the motor housing I Although I do not wish to be limited thereto, l have found that four blades 19g at the concave side 19f of the disk l9e give satisfactory results. The blades 19g preferably are perpendicular or normal to the concave side 19f with the outer extremities thereof closely adjacent to the motor housing 21. With this construction the contours of the edges of the blades 19g more or less conform to the shape of the lower end of the motor housing 21, as seen in FIG. 3. Hence, the blades 19g essentially extend across and bridge the gap 32 between the concave side 19f of the disk 19c with sufficient clearance between the blades 19g and the motor housing 21 to insure unobstructed rotation of the blades on the motor shaft 20. Further, the parts of the blades 19g extending radially outward beyond the side wall of the motor housing 21 become wider or higher and extend axially of the housing toward the outlet 28 and overlap and coextend with the latter in a direction lengthwise the motor housing 21. With this arrangement the outer peripheral parts of the blades 19g essentially wrap themselves about the rounded lower end of the motor housing 21 and form a shroud-like set of blades disposed about the motor housing, thereby insuring optimum performance to maintain the gap 32 substantially free of dust accompanying air flowing through the space 27 toward the outlet 28 from the inlet 25, asindicated by the arrows A in FIG. 3.

As shown in FIG. 2, the blades 19g extend outward on the disk 190 from the vicinity of its axis of rotation to its outer peripheral edge. With this construction the blades 193, during rotation of the fanl9, develop a turbulent air zone above the peripheral edge of the disk 190. This prevents dust-laden air from being radially reflected radially inward into the gap 32 after being moved radially outward by centrifugal force by the blades l9e of the first set at the underside of the disk 19c.

Also, the blades 19g desirably can be provided on the disk at a slight or small angle to the radius. By way of example and without limitation, each of the blades 193 can be arranged at an angle a to a radial line represented by the dotted line aa. The angle a may be in the neighborhood of 2 and formed by each blade 19g intersecting a radial line a-a at a region 35 approximately midway between the axis of rotation of the fan wheel and its periphery, for example. In this way, in addition to developing a turbulent zone at and above the peripheral region of the disk 190, the blades 193 during rotation'will function to effect outward radial movement of dust and other foreign matter in their path of movement by centrifugal force of relatively small magnitude.

In have discovered that a vacuum cleaner of'the kind shown and just described performs with improved suction effect and operates at a lower noise level than heretofore possible.

I claim:

1. In a vacuum cleaner,

a. an electric motor having a housing and a rotatable shaft extending from at least one end thereof,

b. a fan fixed to said shaft at said one end of said motor,

c. a casing which is disposed about said motor and envelops at least said one end thereof and said fan,

the cross-sectional area of said casing being greater than that of said motor housing,

d. said casing and said motor housing defining a passageway having an inlet adjacent to said fan at the vicinity of its axis of rotation and an outlet removed from the inlet, said outlet being in a wall of said casing,

c. said fan comprising a disk which is rotatable with said shaft and spaced from said motor housing at said one end of said motor to provide a gap therebetween,

f. a first set of blades projecting axially of said shaft from one side of said disk facing the inlet, said blades of said first set being distributed on said disk and extending radially outward from its axis of rotation,

g. a second set of blades projecting axially of said shaft from the other side of said disk facing said motor housing at said one end of said motor,

h. the portion of said motor housing coacting with said casing to define said passageway being imperforate,

. said blades of said second set being distributed on said disk and extending from first to second regions thereon, the second regions of said blades of said second set being nearer to the periphery of said disk than the first regions thereof,

j. -said blades of said first set, upon rotation of said fan, functioning to induce flow of dust-laden air through said passageway from said inlet to said outlet thereof, and

k; said blades of said second set, upon rotation of said fan, functioning to maintain the gap between said disk and said imperforate motor housing portion at said one end of said motor substantially free of dust accompanying air flowing through said passageway from said inlet toward said outlet.

2. A vacuum cleaner as set forth in claim 1 in which said blades of said second set extend across and bridge the gap between said disk and said motor housing at said one end of said motor with sufficient clearance therebetween so that unobstructed movement of said fan will be effected when rotating movement is imparted thereto.

3. A vacuum cleaner as set forth in claim 1 in which the outer free edges of said blades of said second set have a contour conforming to the shape of said motor housing at said one end of said motor.

4. A vacuum cleaner as set forth in claim 3 in'which said blades of said second set project radially beyond the side wall of said motor housing.

5. A vacuum cleaner as set forth in claim 4 in which the parts of said blades of said second set projecting radially beyond the side wall of said motor housing extend axially of said motor shaft a greater distance than parts thereof nearer to the axis of rotation of said motor shaft.

6. A vacuum cleaner as set forth in claim 5 in which said blades of said second set essentially wrap themselves about said motor housing at said one end of said motor and form a shroud-like set of blades disposed about said motor housing.

7. A vacuum cleaner as set forth in claim 5 in which the parts of said blades of said second set projecting radially beyond the side wall of said motor housing overlap and coextend with the outlet in the wall of said casing in a direction lengthwise of said motor housing.

8. A vacuum cleaner as set forth in claim 1 which comprises means including at least one of said blades of said second set to throw radially outward by centrifugal force dust and other foreign matter in said gap.

9. A vacuum cleaner as set forth in claim 8 in which at least said one blade of said second set is at an acute angle to the radius of said disk.

10. A vacuum cleaner as set forth in claim 9 in which at least said one blade of said second set is at an acute angle to the radius which is in the neighborhood of about 2".

Claims

1. In a vacuum cleaner, a. an electric motor having a housing and a rotatable shaft extending from at least one end thereof, b. a fan fixed to said shaft at said one end of said motor, c. a casing which is disposed about said motor and envelops at least said one end thereof and said fan, the cross-sectional area of said casing being greater than that of said motor housing, d. said casing and said motor housing defining a passageway having an inlet adjacent to said fan at the vicinity of its axis of rotation and an outlet removed from the inlet, said outlet being in a wall of said casing, e. said fan comprising a disk which is rotatable with said shaft and spaced from said motor housing at said one end of said motor to provide a gap therebetween, f. a first set of blades projecting axially of said shaft from one side of said disk facing the inlet, said blades of said first set being distributed on said disk and extending radially outward from its axis of rotation, g. a second set of blades projecting axially of said shaft from the other side of said disk facing said motor housing at said one end of said motor, h. the portion of said motor housing coacting with said casing to define said passageway being imperforate, i. said blades of said second set being distributed on said disk and extending from first to second regions thereon, the second regions of said blades of said second set being nearer to the periphery of said disk than the first regions thereof, j. said blades of said first set, upon rotation of said fan, functioning to induce flow of dust-laden air through said passageway from said inlet to said outlet thereof, and k. said blades of said second set, upon rotation of said fan, functioning to maintain the gap between said disk and said imperforate motor housing portion at said one end of said motor substantially free of dust accompanying air flowing through said passageway from said inlet toward said outlet.

4. A vacuum cleaner as set forth in claim 3 in which said blades of said second set project radially beyond the side wall of said motor housing.

10. A vacuum cleaner as set forth in claim 9 in which at least said one blade of said second set is at an acute angle to the radius which is in the neighborhood of about 2*.