Patent Publication Number: US-9901232-B2

Title: Vacuum cleaner

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of U.S. patent application Ser. No. 14/150,325, filed Jan. 8, 2014, now U.S. Pat. No. 9,049,972, issued Jun. 9, 2015, which claims the benefit of U.S. Provisional Patent Application No. 61/750,611, filed Jan. 9, 2013, both of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Upright vacuum cleaners employ a variety of dirt separators to remove dirt and debris from a working air stream. Some dirt separators use one or more frusto-conical-shaped separator(s) and others use high-speed rotational motion of the air/dirt to separate the dirt by centrifugal force. Typically, working air enters and exits at an upper portion of the dirt separator as the bottom portion of the dirt separator is used to collect debris. Before exiting the dirt separator, the working air may flow through an exhaust grill. The exhaust grill can have perforations, holes, vanes, or louvers defining openings through which air may pass. 
     BRIEF SUMMARY 
     According to one embodiment of the invention, a vacuum cleaner includes a housing comprising a suction nozzle, a suction source fluidly connected to the suction nozzle for creating a working airstream through the housing, a cyclone separator for separating contaminants from the working airstream, the cyclone separator having an air inlet in fluid communication with the suction nozzle, at least one separation chamber, and an air outlet, and an exhaust grill mounted within the at least one separation chamber and fluidly upstream from the air outlet such that the working air stream passes through the exhaust grill before reaching the air outlet. The exhaust grill has a central axis and includes a body having a side wall, a plurality of inlet openings in the side wall to provide fluid communication between the at least one separation chamber and the air outlet, and a plurality of airflow deflectors formed by closed portions of the side wall that are outwardly spaced in a radial direction, relative to the central axis, from the inlet openings. 
     According to another embodiment of the invention, a vacuum cleaner includes a housing comprising a suction nozzle, a suction source fluidly connected to the suction nozzle for creating a working airstream through the housing, a cyclone separator for separating contaminants from the working airstream, the cyclone separator having an air inlet in fluid communication with the suction nozzle, at least one separation chamber, and an air outlet, and an exhaust grill mounted within the at least one separation chamber and fluidly upstream from the air outlet such that the working air stream passes through the exhaust grill before reaching the air outlet. The exhaust grill has a central axis and includes a body having a plurality of convex projections which project outwardly in a radial direction relative to the central axis, and at least one inlet opening in the body between the convex projections. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of a vacuum cleaner according to a first embodiment of the invention; 
         FIG. 2  is a cross-sectional view through a separation/collection module of the vacuum cleaner, taken through line II-II of  FIG. 1 ; 
         FIG. 3  is a perspective view of an exhaust grill of the separation/collection module shown in  FIG. 2 ; 
         FIG. 4  is a side view of the exhaust grill shown in  FIG. 3 ; 
         FIG. 5  is a top view of the exhaust grill shown in  FIG. 3 ; 
         FIG. 6  is a perspective view of an exhaust grill according to a second embodiment of the invention; 
         FIG. 7  is a side view of the exhaust grill shown in  FIG. 6 ; and 
         FIG. 8  is a bottom view of the exhaust grill shown in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     The invention relates to vacuum cleaners and in particular to vacuum cleaners having dirt separation and collection assemblies. In one of its aspects, the invention relates to a dirt separation and collection assembly having an exhaust grill positioned between the dirt separator and the air outlet from the assembly. For purposes of description related to the figures, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in  FIG. 1  from the perspective of a user behind the vacuum cleaner, which defines the rear of the vacuum cleaner. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. 
     Referring to the drawings, and in particular to  FIG. 1 , an upright vacuum cleaner  10  according to a first embodiment of the invention comprises an upright handle assembly  12  pivotally mounted to a foot assembly  14 . The handle assembly  12  further comprises a primary support section  16  with a grip  18  on one end to facilitate movement by a user. A motor cavity  20  is formed at an opposite end of the handle assembly  12  to contain a conventional suction source  240  ( FIG. 2 ) such as a vacuum fan/motor assembly oriented transversely therein for creating a working airstream through the vacuum cleaner  10 . The handle assembly  12  pivots relative to the foot assembly  14  through a pivot axis that is coaxial with a motor shaft (not shown) associated with the vacuum fan/motor assembly. A post-motor filter housing  22  is formed above the motor cavity  20  and is in fluid communication with the vacuum fan/motor assembly, and receives a filter media (not shown) for filtering air exhausted from the vacuum fan/motor assembly before the air exits the vacuum cleaner  10 . A mounting section  24  on the primary support section  16  of the handle assembly  12  receives a separation/collection module  26  for separating dirt and other contaminants from a dirt-containing working airstream. 
     The foot assembly  14  comprises a housing  28  with a suction nozzle  30  formed at a lower surface thereof and that is in fluid communication with the vacuum fan/motor assembly. While not shown, an agitator can be positioned within the housing  28  adjacent the suction nozzle  30  and operably connected to a dedicated agitator motor, or to the vacuum fan/motor assembly within the motor cavity  20  via a stretch belt. Rear wheels  32  are secured to a rearward portion of the foot assembly  14  and front wheels (not shown) are secured to a forward portion of the foot assembly  14  for moving the foot assembly  14  over a surface to be cleaned. When the separation/collection module  26  is received in the mounting section  24 , as shown in  FIG. 1 , the separation/collection module  26  is in fluid communication with, and fluidly positioned between, the suction nozzle  30  and the vacuum fan/motor assembly within the motor cavity  20 . At least a portion of the working air pathway between the suction nozzle  30  and the separation/collection module  26  can be formed by a vacuum hose  34  that can be selectively disconnected from fluid communication with the suction nozzle  30  for above-the-floor cleaning. 
     Referring to  FIG. 2 , the separation/collection module  26  of the first embodiment comprises a housing  35  at least partially defining a single-stage separation or cyclone chamber  36  for separating contaminants from a dirt-containing working airstream and an integrally-formed dirt collection chamber  38  which receives contaminants separated by the cyclone chamber  36 . 
     The module housing  35  is common to the cyclone chamber  36  and the collection chamber  38 , and includes a side wall  40 , a bottom wall  42 , and a cover  44 . The side wall  40  is illustrated herein as being generally cylindrical in shape, with a diameter that increases in a direction toward the bottom wall  42 . The bottom wall  42  comprises a dirt door that can be selectively opened, such as to empty the contents of the collection chamber  38 . 
     An inlet to the separation/collection module  26  can be at least partially defined by an inlet conduit  46 . An outlet from the separation/collection module  26  can be at least partially defined by an outlet conduit  48  extending from the cover  44 . The inlet conduit  46  is in fluid communication with the suction nozzle  30  ( FIG. 1 ) and the outlet conduit  48  is in fluid communication with a suction source  240 , such as a vacuum fan/motor assembly, within the motor cavity  20  ( FIG. 1 ). 
     While the cyclone chamber  36  and collection chamber  38  are shown herein as being integrally formed, it is also contemplated that the separation/collection module  26  can be provided with a separate dirt cup having a closed or fixed bottom wall and that is removable from the cyclone chamber  36  to empty dirt collected therein. Furthermore, while a single-stage cyclone is illustrated herein, it is also contemplated that the separation/collection module  26  can be configured with multiple separation stages. As illustrated herein, the separation and collection module is shown as a cyclone separator  26 . However, it is understood that other types of separation modules can be used, such as centrifugal separators or bulk separators. 
     The dirt door  42  is pivotally mounted to the side wall  40  by a hinge  50 . A door latch  52  is provided on the side wall  40 , opposite the hinge  50 , and can be actuated by a user to selectively release the dirt door  42  from engagement with the bottom edge of the side wall  40 . The door latch  52  is illustrated herein as comprising a latch that is pivotally mounted to the side wall  40  and spring-biased toward the closed position shown in  FIG. 2 . By pressing the upper end of the door latch  52  toward the side wall  40 , the lower end of the door latch  52  pivots away from the side wall  40  and releases the dirt door  42 , under the force of gravity, allowing accumulated dirt to be emptied from the collection chamber  38  through the open bottom of the module housing  35 . A gasket  54  can be provided between the dirt door  42  and the bottom edge of the side wall  40  to seal the interface therebetween when the dirt door  42  is closed. 
     The separation/collection module  26  further includes an exhaust grill  58  for guiding working air from the cyclone chamber  36  out of the separation/collection module  26 . The exhaust grill  58  is positioned in the center of the cyclone chamber  36  and can depend from a top wall  56  of the chamber  36 . A separator plate  60  can be provided below the exhaust grill  58  to separate the cyclone chamber  36  from the collection chamber  38 , and can include a disk-like surface  62  extending radially outwardly from the grill  58  and a downwardly depending peripheral lip  64 . A debris outlet  66  from the cyclone chamber  36  can be defined between the separator plate  60  and the side wall  40 . 
     The exhaust grill  58  separates the cyclone chamber  36  from a passageway  68  leading to an optional pre-motor filter assembly  70  within the cover  44  that is upstream of the outlet conduit  48 , such that air exiting the cyclone chamber  36  must pass through the filter assembly  70  prior to passing out of the module  26 . In alternate embodiments where the separation/collection module  26  is configured with multiple separation stages, the exhaust grill  58  can separate a first, downstream cyclone chamber from a second, upstream cyclone chamber. 
     The top wall  56  includes a central opening  72  allowing air to pass out of the exhaust grill  58 . A handle grip  74  attached to the cover  44  can be gripped by a user to facilitate lifting and carrying the entire vacuum cleaner  10  or just the separation/collection module  26  when removed from the vacuum cleaner  10 . The handle grip  74  can be provided with a latch  76  for selectively detaching the separator/collection module  26  from the upright assembly  12  ( FIG. 1 ). 
     Referring to  FIGS. 3-5 , the exhaust grill  58  includes a generally cylindrical body having an open bottom wall  80  defining a lower edge of the body and a side wall  82  which extends upwardly from the bottom wall  80  to an open upper edge  84 . The side wall is provided with multiple airflow deflectors which act to direct debris away from the exhaust grill  58  and also to slow down the airflow passing through the exhaust grill  58 . As illustrated, the side wall  82  has a sawtooth-shaped cross-section when viewed from above, and includes airflow deflectors in the form of a plurality of sawtooth projections  86  extending longitudinally between the bottom wall  80  and the upper edge  84 . The overall shape of the grill  58  may be tapered, such that the width of the grill  58  is wider at the upper edge  84  than at the bottom wall  80 . As illustrated, the diameter of the grill  58  at the upper edge  84  is greater than the diameter of the grill  58  at the bottom wall  80 . 
     As illustrated, the sawtooth projections  86  are substantially vertically-oriented and include a circumferentially-extending surface  88  connected to a radially-extending surface  90  at an outer edge  92 , with the radially-extending surface  90  of one sawtooth projection  86  connected to the circumferentially-extending surface  88  of an adjacent sawtooth projection  86  at an inner edge  94 . The radially-extending surfaces  90  can extend at an angle to a central axis X of the grill  58  so that the lower edge defined by the bottom wall  80  appears twisted relative to the upper edge  84 . The outer and inner edges  92 ,  94  can further be substantially parallel to each other, such that the outer face of the radially-extending surface  90  is substantially flat. 
     At least some of the radially-extending surfaces  90  are partially open in order to provide fluid communication between the cyclone chamber  36  and the passageway  68  ( FIG. 2 ). As shown herein, a majority of the radially-extending surfaces  90  can include adjacent inlet slots  96  that extend substantially the entire length of the inlet surface  90 . In one embodiment, two inlet slots  96  are employed. The inlet slots  96  can be separated by a dividing wall  98  which extends from an inner surface of the radially-extending surface  90 . 
     At least one of the radially-extending surfaces  90  can be closed, i.e. solid, and is not provided with any inlet slots. The closed radially-extending surfaces  90  can be oriented in opposing relationship to the inlet conduit  46  ( FIG. 2 ) in order to prevent any incoming debris from immediately entering the grill  58  without first passing around an inner portion of the side wall  40  of the separator module  35 . 
     The circumferentially-extending surfaces  88  are closed, i.e. solid, and interact with the working air flow to rebound debris away from the inlet slots  96 . The surfaces  88  are outwardly spaced in a radial direction from the inlet slots  96 , which allows debris to deflect off the surfaces  88  before reaching the inlet slots  96 . 
     A void  100  is defined between the outer edges  92  of adjacent sawtooth projections  86 . The outer edges  92  project to define an effective circumference of the generally cylindrical body of the exhaust grill  58 , as indicated by the dashed line in  FIG. 5 , such that a plurality of voids  100  are defined between adjacent sawtooth projections  86  and the effective circumference. The effective circumference may define a maximum effective circumference of the exhaust grill  58 , with the inner edges  94  defining a minimum effective circumference. As illustrated, each void  100  is bounded by one of the inner edges  94  the outer edges  92  of the adjacent projections  86 , and the maximum effective circumference. 
     The voids  100  define zones of reduced flow velocity at the inlet slots  96 , which increases debris separation. The working air flow and entrained debris that swirl around the cyclone chamber  36  ( FIG. 2 ) during operation has both a rotational velocity and a radial velocity. In one example, the rotational velocity can be characterized by the number of rotations debris makes around the cyclone chamber  36  per unit of time and the radial velocity can be characterized by the speed of debris moving along a radial axis originating from the center of the exhaust grill  58 . 
     The sawtooth projections  86  can reduce the distance between the outer perimeter of the exhaust grill  58 , defined by the outer edges  92 , and the side wall  40  of the separator module  35 , which increases the rotational velocity of the working air flow due to the Bernoulli Effect. Debris moving at a higher rotational velocity tends to pass over or past the void  100 , rather than being drawn into the void  100  and through the inlet slots  96 , because the debris has relatively high inertia and is thus more resistant to changing its trajectory compared to slower moving debris found around exhaust grills without the sawtooth projections  86 . 
     Similarly, the circumferentially-extending surfaces  88  and sawtooth projections  86  tend to deflect working air flow and entrained debris outwardly, which increases the outward radial velocity of the working air flow and entrained debris. The increased outward radial velocity increases inertia of the entrained debris, which can overcome the inward radial velocity of the working air passing through the inlet slots  96 . Thus, the debris is more resistant to being drawn inwardly into the void  100  and through the inlet slots  96 , which improves debris separation performance since more debris is retained in the separator module  35 . Accordingly, the void  100  defines a zone of reduced rotational and radial flow velocity at the inlet slots  96 , which reduces the possibility of debris being drawn through the inlet slots  96 , thereby improving debris separation performance. 
     Referring to  FIG. 2 , in which the flow path of working air is indicated by arrows, the operation of the separation/collection module  26  will be described. The suction source  240 , when energized, draws dirt and dirt-containing air from the suction nozzle  30  ( FIG. 1 ) to the inlet conduit  46  and into the separation/collection module  26  where the dirty air swirls around the cyclone chamber  36 . It is noted that while the working air within the cyclone chamber  36  flows along an airflow path having both horizontal and vertical components with respect to a central axis of the module  26 , the magnitude of the horizontal component is greater than the magnitude of the vertical component. Debris D falls into the collection chamber  38 . The working air, which may still contain some smaller or finer debris, then passes through the exhaust grill  58 , which can separate out some additional debris by provision of the airflow deflectors, which act to direct debris away from the exhaust grill  58  and also to slow down the airflow passing though the exhaust grill  58 . The working air, which may still contain some even smaller or finer debris, proceeds upwardly within the passageway  68  and enters the pre-motor filer assembly  70 , where additional debris may be captured. The working air then exits the separation/collection module  26  via the outlet conduit  48 , and passes through the suction source  240  before being exhausted from the vacuum cleaner  10 . One or more additional filter assemblies (not shown) may be positioned upstream or downstream of the suction source  240 . To dispose of collected dirt and dust, the separation/collection module  26  is detached from the vacuum cleaner  10  to provide a clear, unobstructed path for the debris captured in the collection chamber  38  to be removed. 
       FIG. 6-8  illustrate an exhaust grill  110  according to a second embodiment of the invention. The exhaust grill  110  can be used in place of the exhaust grill  58  on the vacuum cleaner  10  shown in  FIG. 1-2 . The exhaust grill  110  includes a generally cylindrical body having an open bottom wall  112  and a side wall  114  which extends upwardly from the bottom wall  112  to an open upper wall  116 . The overall shape of the grill  110  may be tapered, such that the width of the grill  110  is wider at the upper wall  116  than at the bottom wall  112 . As illustrated, the diameter of the grill  110  at the upper wall  116  is greater than the diameter of the grill  110  at the bottom wall  112 . 
     The side wall  114  has a plurality of inlet openings  118  to provide fluid communication between the cyclone chamber  36  and the passageway  68  ( FIG. 2 ). The inlet openings  118  can be provided as a series of holes extending through the side wall  114 . 
     The side wall  114  is provided with multiple airflow deflectors which act to direct debris away from the exhaust grill  110  and also to slow down the airflow passing though the exhaust grill  110 . As illustrated, the airflow deflectors include a plurality of rounded or convex projections  120  extending longitudinally between the bottom wall  112  and the upper wall  116 . The convex projections  120  are substantially vertically-oriented and can extend substantially parallel to a central axis X of the grill  110 . The convex projections  120  can be longitudinally shaped to have an upper cylindrical portion  122  and a lower truncated cone portion  124 . When viewed from below, as in  FIG. 8 , both portions  122 ,  124  have a rounded cross-sectional shape that extends radially outwardly from the side wall  114 . The top wall  116  of the grill  110  can extend outwardly beyond the convex projections  120 . 
     The sections of the side wall  114  in between the convex projections  120  can be provided with inlet openings  118 , but the convex projections  120  themselves are closed, i.e. solid, and interact with the working air flow to rebound debris away from the inlet openings  118 . The projections  120  are outwardly spaced in a radial direction from the inlet openings  118 , which allows debris to deflect off the projections  120  before reaching the inlet openings  118 . 
     A void  126  is defined between the outermost portions of adjacent convex projections  120 . The convex projections  120  project to define an effective circumference of the generally cylindrical body of the exhaust grill  110 , as indicated by the dashed line in  FIG. 8 , such that a plurality of voids  126  are defined between adjacent projections  120  and the effective circumference. The effective circumference may define a maximum effective circumference of the exhaust grill  110 , with the side wall  114  between the projections  120  defining a minimum effective circumference. As illustrated, each void  126  is bounded by a section of the side wall  114 , the outermost portions of the adjacent convex projections  120 , and the maximum effective circumference. Similar to the description of the previous embodiment, the void  126  defines a zone of reduced rotational and radial flow velocity at the inlet openings  118 , which reduces the possibility of debris being drawn therethrough, thereby improving debris separation performance. 
     In particular, the convex projections  120  can reduce the distance between the outer perimeter of the exhaust grill  110  and the side wall  40  of the separator module  35  ( FIG. 2 ), which increases the rotational velocity of the working air flow due to the Bernoulli Effect. Debris moving at a higher rotational velocity tends to pass over or past the void  126 , rather than being drawn into the void  126  and through the inlet openings  118 , because the debris has relatively high inertia and is thus more resistant to changing its trajectory compared to slower moving debris found around exhaust grills without the convex projections  120 . 
     Also, the convex projections  120  tend to deflect working air flow and entrained debris outwardly, which increases the outward radial velocity of the working air flow and entrained debris. The increased outward radial velocity increases inertia of the entrained debris, which can overcome the inward radial velocity of the working air passing through the inlet openings  118 . Thus, the debris is more resistant to being drawn inwardly into the void  126  and through the inlet openings  118 , which improves debris separation performance since more debris is retained in the separator module  35 . 
     At least one section  128  of the side wall  114  is closed, i.e. solid, and is not provided with any inlet openings  118 . The closed section  128  can be oriented in opposing relationship to the inlet conduit  46  ( FIG. 2 ) in order to prevent any incoming debris from immediately entering the grill  110 . 
     The vacuum cleaner disclosed herein provides an improved dirt separation and collection assembly, particularly with regard to the exhaust grill  58 ,  110 . One advantage that may be realized in the practice of some embodiments of the described vacuum cleaner is that the exhaust grill  58 ,  110  is provided with airflow deflectors, which act to direct debris away from the exhaust grill  58 ,  110 . With some previous exhaust grills, debris can enter the inlets of the exhaust grill, rather than being collected, which can lead to the debris clogging a downstream filter, entering the downstream suction source, and/or being exhausted from the vacuum cleaner  10  back into the environment. The exhaust grill  58 ,  110  described herein has closed, projecting surfaces  88 ,  120  which deflect or rebound debris away from the inlets to the exhaust grill  58 ,  110 . 
     Another advantage that may be realized in the practice of some embodiments of the described vacuum cleaner is that the exhaust grill  58 ,  110  is provided with void spaces  110 ,  126  between projecting surfaces  88 ,  120 , which acts to lower the velocity of the airflow passing though the exhaust grill  58 ,  110  and increase debris separation. 
     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. For example, while the cyclone module assemblies illustrated herein are shown having two concentric stages of separation, it is understood that the louvered exhaust grill could be applied to a single stage separator, multiple parallel first and/or second stage, or additional downstream separators, or other types of cyclone separators. Reasonable variation and modification are possible with the scope of the foregoing disclosure and drawings without departing from the spirit of the invention which, is defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.