Patent Publication Number: US-7900316-B2

Title: Filter for a vacuum cleaner

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to vacuum cleaner filtration. In one of its aspects, the invention relates to a filtration assembly for a vacuum cleaner. In another of its aspects, the invention relates to a fine particle filter for filtering particles downstream from a primary particle separator. In yet another of its aspects, the invention relates to a filtration assembly for a vacuum cleaner. 
     2. Description of the Related Art 
     Upright vacuum cleaners have a main filtration or separation assembly for separating dirt and debris from air drawn into the vacuum cleaner by suction force. The main filtration assembly typically comprises a conventional filter bag or a centrifugal separator. Vacuum cleaners with a centrifugal separator may employ a cyclone separator as a main filtration or separation assembly, such as a frusto-conical shaped separator, while others use high-speed rotational motion of the air/dirt in a cylindrical separator to separate the dirt by centrifugal force. Typically, working air enters and exits at an upper portion of the cyclone separator and the bottom portion of the cyclone separator is used to collect debris. It is further known to employ multiple serial cyclone separators to improve the collection of fine debris particles that may not be collected by a single separator. 
     Vacuum cleaners further have at least one motor/fan assembly for generating suction to draw air and debris into the vacuum cleaner. In some models, a second motor/fan assembly is used to drive an agitator, such as a brushroll. Air to cool to the motor/fan assemblies is drawn into the vacuum cleaner and subsequently exhausted from the housing through separate ports in vacuum cleaner housing. As the air passes through the motor, carbon dust discharged from the motor brushes can become entrained in the air and thus also exhausted from the vacuum cleaner, leading to contamination of the home environment. Some effort has been made to filter the motor cooling air after it has passed through the vacuum cleaner. A second or auxiliary filtration assembly comprising a “mechanical” filter can be employed for this purpose. A filter can be placed at the inlet or exhaust port to remove carbon dust from the motor cooling air, however, this filter adds expense and bulk to the vacuum cleaner. A high efficiency particle arrestor (HEPA) filter is commonly used for the second filtration assembly. 
     Even those vacuum cleaners having means to collect fine debris and to filter the motor cooling air after it passes through the motor do not protect the home environment from certain bacteria and molds that may be drawn from a carpet or other surface and rendered airborne by the exhaust form the vacuum cleaner, spreading unpleasant odors and unhealthy bacteria. The vacuum cleaner can suction up bacteria and mold, but then these undesirable items are exhausted back into the home environment because their small size prohibits collection by a cyclone separator. 
     SUMMARY OF THE INVENTION 
     According to the invention, a filter assembly for a vacuum cleaner comprises a filter carrier having a rectilinear shape includes a pair of opposed side walls, each having a arced rear edge, a pair of opposed end walls that are shorter in width than the side walls, each end wall having a rear edge and a protrusion extending away from at least one end wall, the rear edges of the side and end walls defining a concave air inlet opening; and a front surface having an air outlet. A filter element is adapted to be mounted within the filter carrier. 
     In one embodiment, a resilient gasket is adapted to be mounted on the rear edges of the side and end walls to form a seal between the filter carrier and a filter receiver. 
     In another embodiment, the protrusions can have a planar surface oriented generally perpendicular to the end wall and generally parallel to and spaced from the rear edge. One of the protrusions forms a ramp that extends from a top surface of the planar surface towards the rear edge, increasing in height in a direction away from the air inlet. In one embodiment, the other protrusion forms an arc from the top of the second planar surface towards the rear edge. The protrusion that forms the ramp is adapted to seat behind a resilient tab. The protrusion that forms the arc is adapted to seat in a slot. 
     The resilient gasket is typically affixed to the rear edges of the side and end walls to form a seal between the filter carrier and the filter receiver. Further, both the side walls and end walls are impermeable. 
     The filter element can take number of forms. However, a pleated filter, preferably a pleated HEPA filter is preferred. Further, the filter element has a reinforcing rib along the length thereof and between the sides thereof. In a preferred embodiment of the invention, the filter element is sealed within the filter carrier. Further, the radius of curvature of the arced rear edges of the side walls is in the range of about 700 mm to about 870 mm, and is preferably about 786 mm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of a vacuum cleaner comprising a filter assembly according to the present invention. 
         FIG. 2  is an exploded view of the filter assembly comprising a filter receiver, a filter carrier, and a filter cover. 
         FIG. 3  is a right perspective view of the filter receiver from  FIG. 2 . 
         FIG. 4  is a left perspective view of the filter receiver from  FIG. 2 . 
         FIG. 5  is a partial bottom perspective view of the filter receiver from  FIG. 3   
         FIG. 6A  is a partial top perspective view of the filter receiver from  FIG. 3 , illustrating a resilient tab on the filter receiver. 
         FIG. 6B  is a bottom perspective view of the resilient tab from  FIG. 5   a.    
         FIG. 7  is a front view of the filter carrier from  FIG. 2 . 
         FIG. 8  is a side view of the filter carrier from  FIG. 2 . 
         FIG. 9  is a rear view of the filter carrier from  FIG. 2 . 
         FIG. 10  is a partial top perspective view of the filter carrier from  FIG. 7 , illustrating a first protrusion on the filter carrier. 
         FIG. 11  is a partial bottom perspective view of the filter carrier from  FIG. 7 , illustrating a second protrusion on the filter carrier. 
         FIG. 12  is a schematic illustration showing various dimensions of the filter carrier. 
         FIG. 13  is a front view of the filter cover from  FIG. 2 . 
         FIG. 14  is a partial top perspective view of the filter cover from  FIG. 13 , illustrating a resilient tab on the filter cover. 
         FIG. 15  is a partial bottom perspective view of the filter cover from  FIG. 13 , illustrating a catch on the filter cover. 
         FIG. 16  is a perspective view of the filter assembly, illustrating the mounting of the filter carrier to the filter receiver. 
         FIG. 17  is a perspective view of the filter assembly, illustrating the mounting of the filter cover to the vacuum cleaner. 
         FIG. 18  is a partial cross-sectional view taken through line  18 - 18  of  FIG. 1 , illustrating the upper portion of the filter assembly. 
         FIG. 19  is a partial cross-sectional view taken through line  18 - 18  of  FIG. 1 , illustrating the lower portion of the filter assembly. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, and in particular to  FIG. 1 , an upright vacuum cleaner  10  comprises a filter assembly  12  according to the present invention. The vacuum cleaner further comprises an upright assembly  14  pivotally mounted to a base assembly  16 . The filter assembly  12  is generally located on the upright assembly  14 . Other components that are common to a vacuum cleaner, such as a suction nozzle, agitator or brushroll, dust collector, motor/fan assembly, etc., are not germane to the invention and are not described in detail herein. A more detailed description of these and other common components can be found in International Patent Application PCT PCT/US2006/026695 published Jan. 12, 2007 and entitled “Vacuum Cleaner Upright Assembly” which is incorporated herein by reference in its entirety. 
     Referring to  FIG. 2 , the filter assembly  12  comprises a filter receiver  18 , a removable and replaceable filter carrier  20  and a removable filter cover  22 . The filter receiver  18  is preferably affixed to the vacuum cleaner  10  or integral therewith, or can alternately be removable from the vacuum cleaner  10 . In the illustrated embodiment, the filter receiver  18  is affixed within a recess  24  formed on one side of the upright assembly  14  of the vacuum cleaner  10 . The filter receiver  18  receives and supports the filter carrier  20 , while the filter carrier  20  receives and supports the filter cover  22 ; however, the filter receiver  18  could alternately receive and support both the filter carrier  20  and the filter cover  22 . 
     Referring to  FIGS. 3-4 , the filter receiver  18  comprises first and second housing portions  26 ,  28 , respectively that are integrally formed with one another, the first housing portion  26  defining an elongated airflow chamber  30  and the second housing portion  28  serving as a support for the filter carrier  20 . The first housing portion  26  is formed by a top wall  32 , bottom wall  34 , rear wall  36 , right side wall  38 , and left side wall  40 . The top, bottom, rear, and right side walls  32 - 38  are generally planar. The left side wall  40  comprises a first curved surface  42  and a second planar surface  44 . The first curved surface  42  extends from the rear wall  36  to the second planar surface  44  and from the top wall  32  to the bottom wall  34  and is oriented so that the width of the airflow chamber  30 , defined as the distance between the right side wall  38  and the left side wall  40 , increases in a direction away from the rear wall  36 . The second planar surface  44  extends from the first curved surface  42  to the second housing portion  28  and from the top wall  32  to the bottom wall  34 . Generally horizontal ribs  45  can be formed on the right and left side walls  38 ,  40 . 
     The airflow chamber  30  extends through the bottom wall  34  and opens into a conduit  46  for fluid communication with a motor/fan assembly (not shown) that generates suction to draw air and debris into the vacuum cleaner  10 . The conduit  46  extends away from the bottom wall  34 , and at least a portion of the conduit  46  can be integrally formed with the filter receiver  18 . 
     The second housing portion  28  comprises spaced top and bottom walls  48 ,  50  joined by spaced right and left side walls  52 ,  54 . A stepped wall  56  joins the second housing portion  28  to the first housing portion  26  so that the width and height of the second housing portion  28  is slightly larger than that of the first housing portion  26 . 
     Referring to  FIG. 5 , the bottom wall  50  has a slot  58  formed therethrough that is generally rectangular in shape. A flange  60  extends normally from a bottom surface  62  of the bottom wall  50  in spaced relation to the conduit  46  and abuts the slot  58  on one side. 
     Referring to  FIGS. 6A-6B , the top wall  48  has a cut-out  64  defined by two side portions  66  and a rear portion  68  of the top wall  48 . A resilient tab  70  extends forwardly from the rear portion  68  and comprises a pair of arms  72  that are joined to a tab body  74 . The tab  70  can flex about the rear portion  68  in a vertical direction. Strengthening ribs  76  can be formed with the arms  72  and top walls  32 ,  48  of the first and second housing portions  26 ,  28  to allow for repeated flexing of the tab  70 . The tab body  74  further comprises a ridge  82  extending substantially across the forward edge of its top surface. The bottom surface of the tab body  74  has an indentation  84  formed adjacent the forward edge of the tab  70  and a catch  86  that extends normally from the bottom surface. 
     Referring to  FIGS. 7-9 , the filter carrier  20  is generally rectilinear in shape and supports a filter element  88  for removing airborne particulates, such as dirt, dust, mold, bacteria, or pollen. The filter element  88  can be pleated and made of a particulate filter material, such as a high efficiency particulate air (HEPA) filter. The pleats can be continuous across the width of the filter element  88 . Alternately, the filter element  88  can comprise at least one rib  89  to make the pleats shorter and less likely to break or tear. 
     The filter carrier  20  comprises spaced top and bottom walls  90 ,  92  joined by spaced right and left side walls  94 ,  96 , and a front wall  98 . The filter carrier  20  further comprises a flange  100  that is integrally formed with the rear edges of the top, bottom, right side, and left side walls  90 - 96 . The flange  100  borders an open rear face of the filter carrier  20  that forms an air inlet  102  to the filter element  88 . The top, bottom, right side and left side walls  90 - 96  are preferably impermeable to air, while the front wall  98  is substantially open to form an air outlet  104  from the filter element  88 . Vertical and horizontal ribs  101 ,  103 , respectively, cross the air outlet  104  to strengthen the filter carrier  20  and help support the filter element  88 . 
     A resilient gasket  106  is provided on the rear surface of the flange  100  to provide an airtight seal between the filter carrier  20  and the filter receiver  18 , when the filter carrier  20  is mounted thereon. While the resilient gasket  106  is preferably affixed to the filter carrier  20 , optionally, the resilient gasket  106  could be affixed to a portion of the filter receiver  18 , such as the stepped wall  56 . 
     Protrusions  108 ,  110  are formed on the top and bottom wall  90 ,  92 , respectively. The first and second protrusions  108 ,  110  cooperate, respectively, with the slot  58  and tab  70  to retain the filter carrier  20  on the filter receiver  18 . Referring to  FIG. 10 , the first protrusion  108  comprises a pair of spaced side walls  112  extending normally away from the top wall  90  that are joined by a top wall  114 , and a front planar surface  116  extending generally normally away from the top wall  90  and oriented generally perpendicular to the flange  100  extending along the top wall  90 . The top wall  114  includes a first and second surface  118 ,  120 , where the first surface  118  extends from the flange  100  to the second surface  120  and is acutely angled with the respect the top wall  90  of the filter carrier  20  and the second surface  120  extends from the first surface  118  to the front planar surface  116  and is generally parallel to the top wall  90 . The front planar surface  116  is spaced from the flange  100  and can be formed by the edges of the side and top walls  112 ,  114 . While the first protrusion  108  is illustrated as being substantially hollow, it may alternately be substantially solid. 
     Referring to  FIG. 11 , the second protrusion  110  comprises a pair of spaced side walls  122  extending normally away from the bottom wall  92  that are joined by an arcuate wall  124  extending from the flange  100  to a front engagement surface  126 . Multiple ribs  128  extend between the bottom wall  92  and the arcuate wall  124 , and define at least a portion of the front engagement surface  126 . Alternately, the ribs  128  can be eliminated for a substantially hollow second protrusion  110 , or the second protrusion can be substantially solid. 
     Referring to  FIG. 12 , the rear face of the filter carrier  20  is bowed to give it an arcuate or concave rear surface  130 . Preferably, the front wall  98  is also bowed to give the filter carrier  20  an overall curved profile. The top and bottom walls  90 ,  92  are non-parallel and diverge along different planes in a direction towards the rear surface  130 . The flange  100  is also bowed to follow the arc of the rear surface  130 . Generally, the bow or arc of the rear surface  130  is defined by a radius of curvature R. Preferably, the radius of curvature R of the rear surface  130  is between 700 and 870 mm. 
     By way of example, a filter carrier  20  according to the present invention can have one or more of the following dimensions: a linear distance L F  between the outer surfaces of the flange along the top and bottom walls of 284.5 mm; a linear distance W F  between the outer surface of the flange along the side walls of 70 mm; a thickness T of the flange and or resilient seal of 5 mm; a linear distance D F  between the top and bottom walls along the front surface  100  of 274.4 mm; a linear distance D R  between the inner surfaces of the flange along the rear surface  98  of 273 mm; a maximum length L MAX  between the outermost surfaces of the protrusions of 300.7 mm; a maximum profile width W MAX  between the rear surface of the filter carrier  20  along the top or bottom wall and the farthest point on the front surface  100  of 58.7 mm; and a radius of curvature R of the rear surface  130  of about 786 mm. 
     Referring to  FIG. 13 , the filter cover  22  comprises spaced top and bottom walls  132 ,  134  joined by spaced right and left side walls  136 ,  138  and a front wall  140 . The top, bottom, right side, and left side walls  132 - 138  are preferably contoured to complement the shape of the recess  24 . The filter cover  22  further comprises at least one exhaust opening  142  therethrough to allow air which has passed through the filter element  88  to be exhausted from the vacuum cleaner  10 . Preferably, the filter cover  22  comprises multiple exhaust openings  142  forming a grill  144  on the front wall  140 . As illustrated, the grill  144  comprises a plurality of elongated slats  146  defining the exhaust openings  142  therebetween. 
     Referring to  FIG. 14 , a resilient tab  148  is integrally formed in the top wall  132  and comprises a latch portion  150  and a user-engagable portion comprising a release button  152 . The latch portion  150  has a recess  154  and an engagement surface  156  formed at a rear side of the recess  154 . The latch portion  150  is adapted to seat behind a portion of the recess  24  and retain the upper portion of the filter cover  22  on the vacuum cleaner  10 . The release button  152  is adapted to receive pressure from a user to release the latch portion  150  from the recess  24  by flexing the tab  148  downwardly, thereby freeing the filter cover  22  for removal from the vacuum cleaner  10 . 
     Referring to  FIG. 15 , a generally rigid catch  158  is integrally formed in the bottom wall  134  and comprises an engagement surface  160  adapted to fit within a portion of the recess  24  and retain the lower potion of the cover  22  on the vacuum cleaner  10 . The engagement surface  160  can comprise a first, generally vertical portion  162  and a second, generally curved portion  164 . 
     Both the filter element  88  and the filter carrier  20  are preferably disposable so that when the filter element  88  becomes clogged with particulates, the filter carrier  20  can be removed along with the filter element  88  and disposed of, and a new filter carrier  20  with filter element can be installed in its place. In the course of replacing the filter element  88 , both the filter cover  22  and filter carrier  20  are removed from the vacuum cleaner  10 . 
     Referring to  FIGS. 16-19 , the assembly of the filter assembly is illustrated. Typically, the filter receiver  18  is mounted in the recess  24  of the vacuum cleaner  10  at the point of manufacture and is not done by a home user; thus, this portion of the assembly is not illustrated herein. To mount the filter carrier  20  to the filter receiver  18 , the second protrusion  110  of the filter carrier  20  is inserted into the slot  58  of the filter receiver  18 . The arcuate wall  124  is important for the pivoting of the second protrusion  110  and the filter carrier  20  about an axis while the engagement surface  126  abuts a front edge of the slot  58 . The filter carrier  20  is rotated as indicated by the arrows in  FIG. 15  to bring the first protrusion  108  into engagement with the resilient tab  70 . Specifically, the catch  86  on the tab  70  seats behind the front planar surface  116  of the first protrusion. The filter carrier  20  is generally received within the second housing portion  28  of the filter receiver  18 , with the gasket  106  pressed against the stepped wall  56  to create a substantial airtight seal between the flange  100  and the filter receiver, forcing air from the airflow chamber  30  to pass through the filter element  88 . 
     To attach the filter cover  22 , the catch  158  is inserted into a correspondingly shaped lower retainer  166  formed at a bottom edge of the recess  24  ( FIG. 2 ). The curved portion  164  allows easy pivoting of the filter cover  22  to bring the tab  148  into engagement with an upper retainer  168  formed at an upper edge of the recess  24 . The upper retainer  168  is received within the recess  154 , with an inner surface  170  of the upper retainer  168  in abutting relationship with the engagement surface  156 . 
     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 vacuum cleaner shown herein is illustrated as comprising a cyclone separator, it is understood a vacuum cleaner employing a bag filter or another bagless-type of separation assembly can employ the filter assembly described herein. Moreover, the filter assembly can also be used in conjunction with a vacuum cleaner employing a separate pre-motor filter assembly. Conversely, the filter assembly can, with minimal modifications, function as a pre-motor filter assembly itself. 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.