Abstract:
An automatic lint filter cleaning and lint collection system for a laundry dryer. The apparatus comprises a lint filter pivot chamber, a lint collection chamber, a lint filter housing pivotably mounted between the pivot chamber and collection chamber, a flange between the pivot chamber and collection chamber wherein the filter housing is biased into abutment with the flange, a lint collection container, an auger rotatably mounted within the collection chamber, and a drive assembly operably connected to the lint filter housing and auger. The drive assembly is operable to pivot the filter housing away from the flange and then to release the filter housing such that the filter housing forcibly returns into abutment with the flange and thereby causes the lint filter to release lint into the collection chamber. The drive assembly is operable to rotate the auger and thereby move lint from the collection chamber into the collection container.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/899,918 filed Nov. 5, 2013, the disclosure of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to lint collection systems for laundry dryers and, more particularly, to an automatic lint filter cleaning and lint collection system for laundry dryers. 
       BACKGROUND OF THE INVENTION 
       [0003]    Laundry dryers typically have a rotatable drum that tumbles laundry as it is dried. A blower motor pulls heated air through the tumbling laundry to remove moisture from the laundry. As the air is drawn through the laundry, it picks up lint. The air/lint mixture is then pulled through a lint filter to remove the lint and then the filtered air can either be recycled back into the dryer air flow system or exhausted to the outside of the dryer. The lint filter must be cleaned frequently to prevent lint buildup and interference with proper air flow and dryer function. Lint filters are typically removed by hand and cleaned by a user, preferably after each drying cycle. 
         [0004]    What is needed is an automatic lint filter cleaning and lint collection system to insure proper lint filter cleaning as well as to avoid the inconvenience to users of frequently cleaning lint filters. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention comprises an automatic lint filter cleaning and lint collection apparatus and method for laundry dryers. The preferred lint filter cleaning and lint collection apparatus comprises an apparatus housing, a lint filter pivot chamber formed in an upper portion of the apparatus housing, a lint collection chamber formed in a lower portion of the apparatus housing below the pivot chamber, a lint filter housing pivotably mounted within the apparatus housing between the pivot chamber and the collection chamber, a lint filter secured within the filter housing, and a flange formed along an internal surface of the apparatus housing between the pivot chamber and the collection chamber, wherein the filter housing is biased into abutment with the flange. The preferred apparatus further comprises a lint collection container, a pipe connecting the lint collection chamber and the lint collection container, an auger rotatably mounted within the collection chamber, and a drive assembly operably connected to the lint filter housing and the auger. The drive assembly is operable to pivot the filter housing within the pivot chamber and away from the flange. The drive assembly is further operable to release the filter housing after the filter housing has been pivoted away from the flange such that the filter housing forcibly returns into abutment with the flange, causing the lint filter to release lint adhered thereto into the collection chamber. The drive assembly is further operable to rotate the auger and the auger is operable to move lint from the collection chamber, through the pipe, and into the collection container as the auger rotates. The lint in the collection container can be discarded when the collection container is full. 
         [0006]    These and other features of the invention will become apparent from the following detailed description of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a schematic view showing a typical prior art dryer system. 
           [0008]      FIG. 2  is a schematic view showing the dryer system of the present invention. 
           [0009]      FIG. 3  is a partially exploded front perspective view showing the lint filter cleaning and collection system of the present invention. 
           [0010]      FIG. 4  is a rear perspective view showing the lint filter cleaning and collection system of the present invention. 
           [0011]      FIG. 5  is a top plan view, partially in section, showing the lint filter cleaning and collection system of the present invention. 
           [0012]      FIG. 6  is a side elevation view, partially in section, showing the lint filter cleaning and collection system of the present invention. 
           [0013]      FIG. 7  is an exploded rear perspective view of the drive mechanism of the present invention. 
           [0014]      FIG. 8  is an exploded front perspective view of the drive mechanism of the present invention. 
           [0015]      FIG. 9  is side sectional view of the drive mechanism of the present invention. 
           [0016]      FIG. 10  shows the lint filter housing in the home position. 
           [0017]      FIG. 11  shows the lint filter housing in a partially raised position. 
           [0018]      FIG. 12  shows the lint filter housing in a fully raised position. 
           [0019]      FIG. 13  shows the lint filter housing returning to the home position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    In  FIG. 1 , a typical prior art dryer system is schematically shown, wherein the dryer  10  includes a rotatable drum  11 , an air conduit  12  having a hand removable lint filter (not shown) secured therein, a blower motor  13 , and an air exhaust conduit  14 . The blower motor  13  pulls heated air through the rotatable drum  11 , through the air conduit  12  and lint filter, and then forces the air through the air exhaust conduit  14  to the outside of the dryer. The direction of air flow is indicated by the arrows. 
         [0021]    The preferred embodiment of the present invention is shown in  FIGS. 2-13 . In  FIG. 2 , the invention is schematically shown. In  FIGS. 3-13 , detailed views of the lint filter cleaning and lint collection apparatus  25  and its operation are shown. Referring to  FIG. 2 , the dryer  20  includes a rotatable drum  21 , an air conduit  22 , a blower motor  23 , an air exhaust conduit  24 , and an automatic lint filter cleaning and lint collection apparatus  25 , or “lint collection apparatus”. The blower motor  23  pulls heated air through the rotatable drum  21 , through the air conduit  22 , through the lint collection apparatus  25 , and then forces the air through the air exhaust conduit  24  to the outside of the dryer. The direction of air flow is indicated by the arrows. 
         [0022]    Referring to  FIGS. 3-13 , air from the drum  21  preferably flows through an air inlet  31  into a first air chamber  32 , downwards through a first opening  33  into a lint collection chamber  34 , upwards through a lint filter  40  into a lint filter pivot chamber  36 , through a second opening  37  into a second air chamber  38 , and out of the apparatus  25  through an air outlet  39 . The lint filter  40  is secured within a pivotable lint filter housing  41  operable to pivot within the lint filter pivot chamber  36 . A flange  42  forms a perimeter along an inner surface of the apparatus  25  between the pivot chamber  36  and the collection chamber  34 , wherein the lint filter housing  41  abuts the flange  42  when the filter housing  41  is in a substantially horizontal or “home” position. The filter housing  41  includes a pivot arm  43  operably connected to a drive mechanism  70  and a spring arm  44  operably connected to a spring  46 . The spring first end  47  is preferably attached to the spring arm  44  and the spring second end  48  is preferably attached to the pivot chamber  36  housing such that the filter housing  41  is biased against the flange  42 . The spring  46  can be any type of spring suitable to bias the filter housing  41  against the flange  42 , although a compression spring is preferred. 
         [0023]    The bottom of the lint collection chamber  34  forms a tapering hopper  35  to collect lint  50 . A rotatable auger  51  is mounted within the hopper  35  and extends through a short pipe  61  into a lint collection box  62  through a hole  63  therein. The lint collection box  62  is removably located within a collection box chamber  64 . A lint collection bag  66  is preferably removably securable within the collection box  62 . The collection bag  66  preferably comprises an air impermeable plastic. The collection bag  66  is secured within the collection box  62  such that the bag opening  67  aligns with the collection box hole  63 . The collection box  62  is insertable within the collection box chamber  64  such that the short pipe  61  extends through the collection box hole  63  and collection bag opening  67  into the collection bag  66 , thereby reversibly securing the collection bag  66  to the short pipe  61 . An airtight seal is formed between the collection bag  66  and the short pipe  61 . The inside surface of the short pipe  61  preferably includes a helical protrusion  68  (see  FIG. 6 ) that enhances transfer of lint  50  from the hopper  35  through the pipe  61  and into the collection box  62 , described in greater detail below. 
         [0024]    The auger  51  comprises a shaft  52  having a helical flange  53 . The shaft  52  has a proximal end  55  that extends into the collection box  62  and a distal end  56  that is secured to the drive mechanism  70 . The outside diameter of the helical flange  53  (flight outside diameter) decreases from the distal end  57  of the flight length towards the proximal end  58  of the flight length such that the helical flange  53  has a distal portion outside diameter  54   a  that is greater in the hopper  35  and a proximal portion outside diameter  54   b  that is reduced in the short pipe  61  (see  FIGS. 5 and 6 ). Further, the distance between the adjacent helical revolutions (pitch) decreases from the distal end  57  of the flight length towards the proximal end  58  of the flight length such that the pitch is greater in the hopper  35  and reduced in the short pipe  61  (see  FIGS. 5 and 6 ). This auger design enhances transfer of lint  50  from the hopper  35  into the collection box  62 . The helical protrusion  68  along the inside surface of the short pipe  61 , if present, cooperates with the above described auger design to further enhance transfer of lint  50  from the hopper  35  into the collection box  62 . The helix direction of the auger helical flange  53  is preferably opposite to the helix direction of the short pipe helical protrusion  68 . Thus, if the auger helical flange  53  is a right-handed helix (as shown), the short pipe helical protrusion  68  is preferably a left-handed helix (as shown). The hopper  35  has a bottom end that forms an elongated channel that is slightly wider than the auger  51  and extends from the distal end  57  of the flight length to the short pipe  61  entrance. The bottom surface of the hopper  35  preferably has a distal segment  59   a  immediately subjacent the auger flight length distal end  57  and a recessed proximal segment  59   b  that slopes upward from the distal segment  59   a  to the short pipe  61  entrance, best seen in  FIG. 6 . The recessed proximal segment  59   b  provides space for the lint to collect and the upward slope enhances the transfer of lint  50  from the hopper  35  into the short pipe  61 . 
         [0025]    The drive mechanism  70  comprises a drive motor  71  that drives a drive shaft  72  and drive wheel  73 , a drive belt  74 , and a drive pulley  80 . The drive pulley  80  is mounted for independent rotation about the auger shaft  52 . The drive pulley  80  has a spring  81  and a pin (detent)  82   a ,  82   b  secured within a recess  83  on each side so that each detent  82   a ,  82   b  is operable to extend outward from the drive pulley surface  84 . A proximal detent  82   a  is located on a proximal side  87  of the drive pulley  80  and a distal detent  82   b  is located on a distal side  86  of the drive pulley  80 . An auger drive wheel  90  is preferably mounted adjacent the distal side  86  of the drive pulley  80 , wherein the auger drive wheel  90  is secured to the auger shaft distal end  56  for concomitant rotation. The auger drive wheel  90  includes a sloping arcuate slot  91  that has a first end  92  that is coplanar with the surface  93  of the auger drive wheel  90  and a second end  94  that is recessed below the auger drive wheel surface  93 . A filter housing drive wheel  100  is preferably mounted adjacent the proximal side  87  of the drive pulley  80 , wherein the filter housing drive wheel  100  is mounted for independent rotation about the auger shaft  52 . The filter housing drive wheel  100  includes a sloping arcuate slot  101  that has a first end  102  that is coplanar with the surface  103  of the filter housing drive wheel  100  and a second end  104  that is recessed below the filter housing drive wheel surface  103 . The filter housing drive wheel  100  has an eccentric cam  105  formed along a proximal side  106  thereof. 
         [0026]    The drive mechanism  70  further comprises a crank arm  110  mounted adjacent the proximal side  106  of the filter housing drive wheel  100 . The crank arm  110  has a first end  111  having a hole  112  therein for receiving the eccentric cam  105  of the filter housing drive wheel  100 . The crank arm  110  has a second end  113  that is pivotably connected at a pivot point  114  to a first end  116  of a lift arm  115 . The lift arm  115  has a second end  117  that is pivotably connected to the pivot arm  43  of the filter housing  41 . A cam bar  120  extends from the apparatus  25  housing adjacent the lift arm  115 . 
         [0027]    In operation, the dryer  20  is operated through a drying cycle. The lint filter  40  and filter housing  41  are in the home position shown in  FIG. 10 . After a preset delay at the end of the drying cycle to allow time for air flow to cease, the dryer  20  initiates a lint filter cleaning cycle and the drive mechanism  70  is actuated to clean the lint filter  40 . The drive motor  71  is actuated to rotate the drive wheel  73  in a first direction (e.g. clockwise) which causes the drive pulley  80  to rotate in a first direction (e.g. clockwise) by operation of the drive belt  74 . As the drive pulley  80  rotates in the first direction, the spring-actuated proximal detent  82   a  will slide within the sloping arcuate slot  101  in the filter housing drive wheel  100  until it engages the recessed second end  104  of the arcuate slot  101 , after which, the proximal detent  82   a  will force the filter housing drive wheel  100  to rotate in the first direction concurrently therewith. When the drive pulley  80  is rotating in the first direction, the distal detent  82   b  slides within the sloping arcuate slot  91  of the auger drive wheel  90  but does not engage the auger drive wheel  90  because of the direction of rotation within the arcuate slot  91 . As the filter housing drive wheel  100  rotates in the first direction, the eccentric cam  105  urges the crank arm  110  angularly upwards which, in turn, urges the lift arm  115  angularly upwards, as shown in  FIGS. 11 and 12 . As the lift arm  115  moves upwards, it transmits lifting force to the pivot arm  43  which pivots the filter housing  41  upwards within the pivot chamber  36 . The maximum angle of the filter housing  41  relative to the flange  42  is between 30 to 90 degrees, most preferably 75 degrees. As the eccentric cam  105  reaches its uppermost limit, shown in  FIG. 12 , the lift arm  115  engages the cam bar  120 , which urges the first end  116  of the lift arm  115  and the second end  113  of the crank arm  110  to pivot about pivot point  114  relative to each other and away from cam bar  120 . As this occurs, the upward lifting force of the lift arm  115  is suddenly released and the filter housing  41  rapidly falls back into abutment with the flange  42  (see  FIG. 13 ). This “slapping” action dislodges lint adhered to the filter  40 , allowing the lint to fall into the hopper  35 . As the filter housing drive wheel  100  continues to rotate in the first direction, the eccentric cam  105  urges the crank arm  110  downward and the crank arm  110  and lift arm  115  pivot about pivot point  114  back into linear alignment with each other, as shown in  FIG. 10 . The lint filter cleaning cycle can include one or more, preferably two, of these lint filter “slapping” cycles after each drying cycle. 
         [0028]    After the lint filter cleaning cycle is completed, the dryer  20  initiates a lint collection cycle and the drive mechanism  70  is actuated to transfer lint from the hopper  35  to the collection box  62 . The drive motor  71  is actuated to rotate the drive wheel  73  in a second direction (e.g. counter-clockwise) which causes the drive pulley  80  to rotate in a second direction (e.g. counter-clockwise) by operation of the drive belt  74 . As the drive pulley  80  rotates in the second direction, the spring-actuated distal detent  82   b  will slide within the sloping arcuate slot  91  in the auger drive wheel  90  until it engages the recessed second end  94  of the arcuate slot  91 , after which, the distal detent  82   b  will force the auger drive wheel  90  to rotate in the second direction concurrently therewith. When the drive pulley  80  is rotating in the second direction, the proximal detent  82   a  slides within the sloping arcuate slot  101  of the filter housing drive wheel  100  but does not engage the filter housing drive wheel  100  because of the direction of rotation within the arcuate slot  101 . As the auger drive wheel  90  rotates in the second direction, the auger  51  rotates therewith and the helical flange  53  advances lint  50  from the hopper  35 , through the short pipe  61 , and into the collection bag  66  within the collection box  62 . The lint collection cycle runs for a preset period of time, preferably 20 seconds. Once the lint collection cycle is completed, the dryer  20  will turn off. In an alternate embodiment, the auger  51  may include a reciprocating knife blade (not shown) mounted within the shaft  52  and extending slightly beyond the shaft surface to cut materials, such as hair, that wrap around the shaft  52 . The knife blade can be actuated to cycle back and forth after the auger  51  has ceased rotating. 
         [0029]    The present invention cleans the lint filter  40  after each drying cycle and thus prevents lint buildup and interference with proper dryer function. Depending on the frequency of dryer use, the collection bag  66  should not need to be replaced for at least 6 months. A sensor detects when the collection bag  66  is full and activates a signal light on the dryer  20 . The collection box  62  can be removed by a user through an access panel in the dryer  20 , the collection bag  66  can be easily detached and removed from the collection box  62 , a replacement collection bag  66  can be secured within the collection box  62 , and the collection box  62  can be inserted back into the collection box chamber  64  to engage the short pipe  61 . A safety feature can be included that prevents operation of the dryer  20  when the collection bag  66  is full. 
         [0030]    While the invention has been shown and described in some detail with reference to specific exemplary embodiments, there is no intention that the invention be limited to such detail. On the contrary, the invention is intended to include any alternative or equivalent embodiments that fall within the spirit and scope of the invention as described and claimed herein.