Airflow system for bagless vacuum cleaner

[0001] This application claims the benefit of U.S. Provisional Application No. 60/237,832, filed Oct. 3, 2000.

[0002] The present invention relates generally to the vacuum cleaner art, and, more particularly, to a bagless vacuum cleaner incorporating a novel air flow system.

[0003] A recent consumer products trend has resulted in a rapid increase in the popularity of bagless upright vacuum cleaners. Such vacuum cleaners generally incorporate a washable and rigid dust container or cup for collecting intermediate and larger particles of dirt and debris and a second, upstream corrugated paper, porous foam or like filter or filter cartridge for collecting smaller dirt and dust particles. The intermediate and larger particles of dirt and debris are collected in the dust container or cup usually by establishing a vortex airstream therein which allows the heavier particles to be separated from the airstream and collected in the bottom of the container or cup. Generally, the container or cup is made from transparent or translucent material so that the operator may observe the “cyclonic” cleaning action. This seems to add significantly to the customer satisfaction with the product. Of course, the transparent or translucent container or cup also allows the operator to confirm when the cup or container is nearing capacity. At that time the vacuum cleaner may be switched off and the cup or container removed for emptying into a garbage can or other appropriate dirt receptacle.

[0004] While many available designs exist for bagless vacuum cleaners it should be appreciated that further improvements in design including improvements in air flow so as to provide more cleaning power and more efficient operation are still desired. The present invention meets this goal.

[0005] In accordance with the purposes of the present invention as described herein, an improved bagless vacuum cleaner is provided. The bagless vacuum cleaner includes a nozzle assembly having a suction nozzle for picking up dirt and debris from a surface to be cleaned and a canister assembly including a cavity. The bagless vacuum cleaner also includes a dust collection assembly. That dust collection assembly includes a filtering subassembly and a dust container. The dust container has an open top, a bottom wall and a first cylindrical sidewall. The container also includes an inlet that in at least one embodiment is directed tangentially with respect to the first cylindrical sidewall in order to establish a vortex airstream to allow efficient cleaning action. Still further, the dust container includes a downwardly directed outlet which extends through the bottom wall of the container. The bagless dust collection assembly is received and held in the cavity in the canister assembly.

[0006] The bagless vacuum cleaner further includes an airstream conduit for conveying a vacuum airstream between the suction nozzle and the inlet. Additionally, a suction fan and suction fan drive motor is carried on either the nozzle assembly or the canister assembly. The suction fan and cooperating suction fan drive motor function to generate the vacuum airstream for drawing dirt and debris through the suction nozzle, the airstream conduit and the dust container.

[0007] More specifically describing the invention, the dust container includes a second cylindrical sidewall concentrically received within the first cylindrical sidewall so that at least a portion of the dust container is annular. This second cylindrical sidewall defines an exhaust pathway which is provided in fluid communication with the outlet.

[0008] The filtering subassembly includes a main body and a cooperating cover defining a primary filter cavity. A primary filter is positioned in the primary filter cavity. The primary filter divides the primary filter cavity into an intake chamber and a discharge chamber. The primary filter may take the form of an annular corrugated filter made from paper or other natural and/or synthetic fiber material appropriate for the intended purpose.

[0009] The main body of the filter subassembly includes a downwardly depending exhaust conduit which provides fluid communication between the discharge chamber and the exhaust pathway leading to the outlet. Additionally, the main body includes a first conical wall around the intake chamber.

[0010] A prefilter is carried on the main body. The prefilter extends concentrically around the exhaust conduit but is spaced therefrom so as to form an intake channel between the prefilter and the exhaust conduit. The intake channel is provided in fluid communication with the intake chamber. The prefilter may take the form of a cylindrical open-ended screen.

[0011] An air current guide may be carried on the main body adjacent the prefilter. The air current guide extends between the prefilter and the second cylindrical sidewall. The air current guide includes a disc-like separator and at least one downwardly depending air current guide vane.

[0012] Once fully assembled a first gap having a width W₁ is formed between the prefilter and the first cylindrical sidewall of the dust container. Further, the inlet includes a diameter D₁. The diameter D₁ is ≦ the width W₁. In a typical embodiment, diameter D₁ is between about 30 mm–35 mm and the width W₁ is between about 34 mm–36 mm. Additionally, a second gap having a width W₂ between about 12 mm–16 mm is provided between an outer edge of the separator and the first cylindrical sidewall.

[0013] The vacuum cleaner also includes a filter clicker carried on the cover of the filtering subassembly. The filter clicker includes a cleaning element having at least one projecting lug and an actuator for rotating the cleaning element relative to the primary filter. The primary filter preferably includes a frame for supporting the corrugated filter material. A series of projecting tabs extend from the frame. The projecting lug on the cleaning element engages the series of projecting tabs on the frame vibrating the frame and filter material held by the frame and thereby cleaning dirt from the primary filter when the actuator is manually manipulated.

[0014] In accordance with yet another aspect of the present invention a method is provided for directing airflow through a bagless vacuum cleaner wherein that vacuum cleaner includes a primary filter and a dust container having an inlet and an outlet. The method includes the steps of directing the airflow from the inlet around the dust container, drawing the airflow upwardly through the primary filter and discharging the airflow downwardly through the outlet by passing the airflow through a discharge conduit extending through a bottom wall of the dust container.

[0015] In addition, the present invention may be broadly described as relating to a novel bagless upright vacuum cleaner also providing beltless operation. The bagless upright vacuum cleaner includes a nozzle assembly having a suction nozzle for picking up dirt and debris from a surface to be cleaned and a canister assembly pivotally mounted to the nozzle assembly and including a control handle. The upright vacuum cleaner also includes a washable dust container providing a bagless means for collecting dirt and debris cleaned from the surface. Additionally, an agitator is held in the nozzle assembly. A beltless agitator drive motor carried on the nozzle assembly or the canister assembly is provided for driving the agitator and lifting dirt and debris from the surface. A suction fan and beltless suction fan drive motor carried on the nozzle assembly or the canister assembly generates a vacuum airstream for drawing dirt and debris through the suction nozzle into the dust container.

[0016] Still other objects of the present invention will become readily apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of this invention simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.

[0024] Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawing.

[0025] Reference is now made to FIG. 1 showing the vacuum cleaner 10 of the present invention. It should be appreciated that while an upright vacuum cleaner 10 is illustrated, embodiments of the present invention also include canister vacuum cleaners incorporating a dust collection assembly 12 of the nature that will be described in detail below.

[0026] The upright vacuum cleaner 10 illustrated includes a nozzle assembly 16 and a canister assembly 18. The canister assembly 18 further includes a control handle 20 and a hand grip 22. The hand grip 22 carries a control switch 24 for turning the vacuum cleaner on and off. Of course, electrical power is supplied to the vacuum cleaner 10 from a standard electrical wall outlet through a cord (not shown).

[0027] At the lower portion of the canister assembly 18, rear wheels 26 are provided to support the weight of the vacuum cleaner 10. A second set of wheels 27 allow the operator to raise and lower the nozzle assembly 16 through selective manipulation of the height adjustment switch 28. Such a height adjustment mechanism is well known in the art and is exemplified, for example, by the arrangement incorporated into the Kenmore Progressive Vacuum Cleaner presently in the marketplace. To allow for convenient storage of the vacuum cleaner 10, a foot latch (not shown) functions to lock the canister assembly 18 in an upright position as shown in FIG. 1. When the foot latch is released, the canister assembly 18 may be pivoted relative to the nozzle assembly l6 as the vacuum cleaner 10 is manipulated to-and-fro to clean the floor.

[0028] The canister assembly 18 includes a cavity 32 adapted to receive and hold the dust collection assembly 12. Additionally, the canister assembly 18 carries a suction fan 34 and suction fan drive motor 35. Together, the suction fan 34 and its cooperating drive motor 35 function to generate a vacuum airstream for drawing dirt and debris from the surface to be cleaned. While the suction fan 34 and suction fan drive motor 35 are illustrated as being carried on the canister assembly 18, it should be appreciated that they could likewise be carried on the nozzle assembly 16 if desired.

[0029] The nozzle assembly 16 includes a nozzle and agitator cavity 36 that houses a rotating agitator brush 38. The agitator brush 38 shown is rotatably driven by a motor 40 and cooperating gear drive 42 housed within the agitator and described in greater detail below (see FIGS. 2 and 2a). In the illustrated vacuum cleaner 10, the scrubbing action of the rotary agitator brush 38 and the negative air pressure created by the suction fan 34 and drive motor 35 cooperate to brush and beat dirt and dust from the nap of the carpet being cleaned and then draw the dirt and dust laden air from the agitator cavity 36 to the dust collection assembly 12. Specifically, the dirt and dust laden air passes serially through a suction inlet and hose and/or an integrally molded conduit in the nozzle assembly 16 and/or canister assembly 18 as is known in the art. Next, it is delivered into the cyclonic dust collection assembly 12 (described in greater detail below) which serves to trap the suspended dirt, dust and other particles inside while allowing the now clean air to pass freely through to the suction fan 34, a final filtration cartridge 48 and ultimately to the environment through the exhaust port 50.

[0030] Reference is now made to FIGS. 2 and 2a which show the mounting of the agitator motor 40 and associated gear drive 42 in the agitator 38 in detail. As shown, the agitator 38 is mounted for rotation relative to the nozzle assembly 16. Specifically, a first end of the agitator 38 includes an end cap 52 which is supported on bearings 54 on a stub shaft 55 held in mounting block 56 keyed into slot 58 in the side of the nozzle assembly 16. An end cap 60 at the opposite end of the agitator 38 is supported on bearings 62 mounted on the housing 64 of the motor 40. As should be appreciated, the motor 40 is fixed to the nozzle assembly 16 by means of the mounting block 66 fixed to the motor housing 64 and keyed in the slot 68 in the side of the nozzle assembly.

[0031] The motor 40 drives a shaft 70 including gear teeth 72. The drive shaft 70 extends through a bearing 74 held in the hub 76 of the planetary gear set carrier 78. In the most preferred embodiment a fan 80 is keyed or otherwise secured to the distal end of the drive shaft 70.

[0032] The planetary gear set carrier 78 includes three stub shafts 82 that each carry a planetary gear 84. Each of the planetary gears 84 include teeth that mesh with the gear teeth 72 of the drive shaft 70. Additionally, the planetary gears 82 mesh with the teeth of an annular gear 86 that is fixed to the agitator motor housing 64 by pin or other means. Thus, it should be appreciated that as the drive shaft 70 is driven by the motor 40, the planetary gears 84 are driven around the annular gear 86, thereby causing the planetary gear set carrier 78 to rotate.

[0033] Planetary gear set carrier 78 also includes a drive ring 88 and associated rubber drive boot 87 which includes a series of spaced channels 89 that receive and engage axial ribs 91 projecting inwardly radially from the inner wall of the agitator 38. Thus, the rotation of the planetary gear set carrier 78 is transmitted by the drive ring 88 and drive boot 87 directly to and causes like rotation of the agitator 38. The rubber drive boot 87 provides the necessary damping to insure the smooth transmission of power to the agitator 38. Simultaneously with the rotation of the planetary gear set carrier 78 and agitator 38, the drive shaft 70 also drives the fan 80 at a ratio of between 4-1 to 10-1 and most preferably 6-1 with respect to the agitator 38. The resulting rapid rotation of the fan 80 helps to move air through the agitator 38 and ensure proper cooling of the agitator motor 40 during its operation.

[0034] The dust collection assembly 12 will now be described in detail. The dust collection assembly 12 includes a filtering subassembly generally designated by reference numeral 100 and a dust container 102. Dust container 102 includes an open top 104, a bottom wall 106 and a first cylindrical sidewall 108. An inlet 110 is shown directed tangentially with respect to the cylindrical sidewall 108. In this orientation, the inlet 110 promotes the formation of a vortex airstream as described in greater detail below. It should be appreciated, however, that substantially any other inlet orientation could be utilized and the formation of a vortex airstream is not critical to the present invention.

[0035] A downwardly directed outlet 112 extends through the bottom wall 106. A second or inner cylindrical sidewall 114 is concentrically received within the first cylindrical sidewall 108 so that at least a portion of the dust container 102 is annular. As best shown in FIG. 4, the second cylindrical sidewall 114 defines an exhaust passageway 116 provided in fluid communication with the outlet 112.

[0036] The filtering subassembly 100 includes a main body 118 and a cooperating cover 120. Together the main body 118 and cooperating cover 120 define a primary filter cavity 122. A primary filter 124 is positioned in the primary filter cavity 122 and divides that cavity into an intake chamber 126 and a discharge chamber 128. In one embodiment, the primary filter 124 is an annular corrugated filter made from paper or other natural and/or synthetic fiber material with each of the corrugations held by a plastic frame 130. That frame 130 includes a series of upwardly projecting tabs 132 radially arranged about the primary filter 124.

[0037] The main body 118 includes a downwardly depending exhaust conduit 134 providing fluid communication between the discharge chamber 128 and the exhaust pathway 116 leading to the outlet 112. As also shown the main body 118 includes a frustoconical wall 136 defining the peripheral margin of the intake chamber 126.

[0038] A prefilter 138 is carried on the main body 118 below the frustoconical wall 136. The prefilter 138 is shown as comprising a cylindrical open-ended screen which extends concentrically around the exhaust conduit 134 so as to form an intake channel 140 between the prefilter 138 and the exhaust conduit 134. Of course, other materials such as a porous plastic could be used for the prefilter. The intake channel 140 is provided in fluid communication with the intake chamber 126 through spaced openings 142 in the base 144 of the main body 118.

[0039] As further shown in FIGS. 3 and 4, an air current guide, generally designated by reference numeral 146 is carried by the main body 118 adjacent the prefilter 138. The air current guide 146 extends between the prefilter 138 and the second cylindrical sidewall 114 of the dust container 102. As shown the air current guide 146 includes a disc shaped separator 148 and one or more downwardly depending air current guide vanes 150. Each air current guide vane is canted inwardly between 0°–30° from the vertical toward the second cylindrical sidewall 114. The function of the separator 148 and guide vane 150 will be described in greater detail below.

[0040] In operation, dirt and debris lifted by the agitator brush 38 and drawn through the suction inlet and hose passes through the inlet 110. Inlet 110 directs the air to tangentially flow in a cyclonic path (note action arrows A in FIG. 4) around the dust container 102. Specifically, the air first flows around a prefilter 138 with the heavier debris falling under the force of gravity toward the bottom of the dust container 102. The air current guide vane 150 helps maintain smooth, uninterrupted and unturbulent cyclonic flow in order to maximize cleaning action. Further, the inward cant of the guide vane causes dirt and debris entrained int eh airstream A to move toward the center of the dust container 102. This effectively compacts the dirt and debris allowing the dust container to fill to a higher capacity. The largest and heaviest of the dirt and debris entrained int eh vacuum airstream delivered into the dust container 102 through the inlet 110 settles to the bottom wall 106 of the dust container.

[0041] The vacuum airstream now devoid of the relatively larger and heavier dust, debris and particles is drawn through the prefilter screen 138 into the intake channel 140. The screen includes pores having a diameter of between substantially 40 μm and 300 μm. Relatively intermediate size dust, dirt and debris too light to settle to the bottom of the dust container 102 but too large to pass through the prefilter screen 138 is removed from the vacuum airstream by the prefilter screen. There this material collects and gradually accumulates into a heavier mass which will eventually fall under the force of gravity onto the separator 148 where it will be displaced by the moving airstream and drop down into the bottom of the dust container 102.

[0042] As best shown by action arrow B, the vacuum airstream moving through the prefilter screen 138 into the intake channel 140 is then drawn through one of the apertures 142 in the main body 118 into the intake chamber 126. From the intake chamber 126 the vacuum airstream is drawn upwardly through the primary filter 124 which removes substantially all of the remaining fine dust from the airstream. Next the vacuum airstream is drawn into the discharge chamber 128. From there the vacuum airstream is redirected downwardly through the exhaust conduit 134 and then the exhaust passageway 116 to the outlet 112. From there the airstream passes through a foam or sponge rubber filter pad 152 carried at the bottom wall of the cavity 32 in the canister assembly 18. That filter pad 152 covers the inlet to a passageway (not shown) leading to the suction fan 34. From there the vacuum airstream is exhausted over the suction fan drive motor 35 to provide cooling and is delivered through a sound muffling passageway to the final filtration cartridge 48 and then it is exhausted through the exhaust port 50.

[0043] The flow of the vacuum airstream is carefully shaped and controlled throughout its passage through the vacuum cleaner 10 in order to ensure the highest possible cleaning efficiency. Toward this end a first gap 154 having a width W₁ of between about 34 mm and 36 mm is provided between the prefilter screen 138 and the first cylindrical sidewall 108. The inlet 110 is provided with a diameter D₁ of between about 30 mm and 35 mm. In the most preferred embodiment diameter D₁≦ the width W₁.

[0044] Additionally, a second gap 156 having a width W₂ between about 12 mm and 16 mm is provided between an outer edge of the separator 148 and the first cylindrical sidewall 108. The width W₂ of the gap 156 must be carefully controlled as it allows the separator 148 to concentrate the vacuum airflow from the inlet 110 in the area of the prefilter screen 138 away from the dirt and debris collecting in the bottom of the dust container 102. This is done while simultaneously maintaining a sufficiently large gap 156 to allow the free passage of the larger, heavier dirt and dust particles entrained in the airstream into the lower portion of the dust container 102 where they can be collected.

[0045] During vacuuming, the dust container 102 will gradually fill with dirt and debris which will also collect on the prefilter screen 138. Further, fine dust particles will be collected on the primary filter 124. By forming the dust container 102 and the cover 120 of the filtering subassembly 100 from transparent or translucent plastic material it is possible to visually monitor and inspect the condition of the dust container and primary filter 124 during vacuuming. Following vacuuming or as otherwise necessary it is easy to dispose of this dirt and debris. Specifically, the vacuum cleaner is turned off and the dust collection assembly 12 is removed from the cavity 32 in the canister assembly 18. This may be done by lifting and releasing the latch handle 158 (the operation of which is described in greater detail below) or by simply pulling the dust collection assembly 12 from its nested position if no latch is provided. The latch handle 158 is pivotally connected to the cover 120 and serves as a simple and convenient means of handling the dust collection assembly 12.

[0046] A filter clicker, generally designated by reference numeral 160, allows easy cleaning of the primary filter 124. More specifically, the filter clicker 160 includes a revolving cleaning element 162 shown with a pair of projecting lugs 164. An exposed actuator 166 is carried on the top of the cover 120. The actuator 166 includes a hub 168 which projects through an opening in the cover 120 and engages in a cooperating socket provided in the cleaning element 162. By manually rotating the actuator 166, the cleaning element 162 is likewise rotated and the projecting lugs 164 engage with each of the series of projecting tabs 132 on the frame 130 of the primary filter 124. As the projecting lugs 164 resiliently snap past the projecting tabs 132, the corrugated filter material is vibrated shaking the fine dust and dirt particles from the primary filter 124. Since the projecting tabs 132 are provided around the outer margin of the frame, greater vibration is produced for better cleaning action. These dust and dirt particles then drop under the force of gravity and slide down the frustoconical sidewall 136 of the main body, pass through the apertures 142 and drop down into the bottom 170 of the intake channel 140 where they are captured.

[0047] The cover 120 is then removed from the dust container 102 by twisting. When separated the filtering subassembly 100 including the main body 118, cover 120, prefilter screen 138 and air current guide 146 stay together as a unit. As the filtering subassembly 100 and the dust container 102 are separated, the bottom 170 of the intake channel 140 opens and the fine dirt and debris that is collected there from the cleaning of the primary filter 124 falls under the force of gravity into the bottom of the dust container 102. Similarly, any relatively light dirt and debris remaining on the prefilter screen 138 or the upper ledge of the separator 148 falls easily to the bottom of the container with minor shaking of the filtering subassembly 100 during its removal from the container. The dirt and debris is then dumped from the container 102 into a garbage receptacle. The filtering subassembly 100 is then rejoined with the dust container 102 by twisting the cover 120 onto the threaded upper end of the dust container 102. The entire dust collection assembly 12 is then repositioned in the cavity 32 in the canister assembly 18 with the inlet 110 in communication with a coupling 47 which is in communication with the hose or other conduit leading to the nozzle and the outlet 112 which is in communication with the port 113 leading to the suction fan 34.

[0048] As best shown in FIGS. 3, 5a and 5b, the latch handle 158 is pivotally connected to the cover 120 by opposed stub shafts 200 received in cooperating opposed apertures in the cover. Springs 201 bias the latch handle to the latched position resting flat against the cover 120. When disengaged or unlatched, the latch handle 158 may be utilized in the manner of a handle of a pail to conveniently hold and manipulate the dust collection assembly 12. As the dust collection assembly 12 is being secured in the cavity 32 the latch handle 158 is utilized to provide a positive connection.

[0049] More specifically, the latch handle 158 includes a pair of spaced cams 202 that engage a cooperating lip or shoulder 204 on the canister assembly 18. Thus, as the latch handle 158 is pressed downwardly toward the cover 120, the cams 202 engage the shoulder 204 thereby forcing the dust collection assembly 12 rearwardly and downwardly. This dual action firmly seats the inlet 110 in the coupling 47 and the outlet 112 in the port 113 leading to the suction fan 34. As a result, a good seal is provided at each connection, vacuum pressure losses are avoided and peak operating efficiency of the suction fan is insured.

[0050] Under certain circumstances, such as after extended heavy duty service, it may become necessary to access the primary filter 124. This is relatively easily accomplished. More particularly, the main body 118 and the cover 120 of the filtering subassembly 100 are connected together by means of the upstanding mounting flange 170 on the main body which provides either a threaded or a fiction fit in the cooperating groove 172 of the cover 120. Accordingly, the cover 120 may be pulled or unscrewed from the main body 118 to open the primary filter cavity 122. The primary filter 124 is then replaced with a new filter. The cover 120 is then repositioned on the main body 118 by inserting the mounting flange 170 in the cooperating groove 172 and completing the reconnection.

[0051] The foregoing description of the preferred embodiment of this invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. For example, a back light 180 could be provided behind the dust collection assembly 12 in the cavity 32 of the canister assembly 18 to visually enhance monitoring of the airflow and/or dirt level in the dust container 102. The vacuum cleaner 10 could also include a bypass valve (not shown) in the airstream conduit upstream from the inlet 110. The valve could be spring loaded to permit only high velocity air flow into the dust container 102. If desired, a performance indicator of the type presently found on the Kenmore Model 38912 upright vacuum cleaner could be provided in the airstream conduit to give a true indication of vacuum cleaner performance. Further, while the vacuum cleaner is described with an agitator drive motor held in the agitator, the drive motor could be positioned outside of the agitator in either the nozzle assembly or the canister assembly in any manner desired. Additionally, while the dust collection assembly 12 is illustrated as being carried in a cavity 32 in the canister assembly 18, it should be appreciated that it could also be mounted in a cavity or by means of some other structure on the nozzle assembly 16 as well.

[0052] The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.