Abstract:
A filter assembly for an engine and operable to support a filter element. The filter assembly comprising a housing defining a filter receiving space having a first end and a second end. The first end and second end defining an axial length therebetween. A biasing element is integrally formed as one piece with the housing and disposed adjacent the first end.

Description:
BACKGROUND  
       [0001]     The present invention relates generally to internal combustion engines. More particularly, the present invention relates to air cleaners for internal combustion engines.  
         [0002]     Internal combustion engines mix air with fuel to produce a combustible fuel-air mixture. Before the air enters the engine, it often passes through an air cleaner to remove any undesirable particles (e.g., dirt, grass clippings, twigs, and the like).  
         [0003]     Current air cleaners generally include a pleated filter media contained within a filter housing. Generally, the filter housing includes two halves that bolt together. The filter element is positioned between the two halves and the bolt is tightened until the housing makes solid contact with both ends of the filter media. Thus, the screw is used to assure that the filter media is properly seated within the housing.  
         [0004]     Other air cleaners use simple connections to assemble the housing but require the maintenance of tight tolerances to assure that the filter element is properly positioned. The tight tolerances increase the cost associated with the manufacture of the housing.  
       SUMMARY  
       [0005]     The present invention provides a filter device for an engine and operable to support a filter element. The filter device comprising a housing defining a filter receiving space having a first end and a second end. The first end and second end defining an axial length therebetween. A biasing element is integrally formed as one piece with the housing and disposed adjacent the first end.  
         [0006]     In another aspect, the invention provides an air cleaner assembly for an engine. The assembly includes a base having a filter support and a base engagement portion, and a filter element which together define a longitudinal direction. The assembly also includes a cover including an integrally formed biasing element, and a cover engagement portion. The base engagement portion is engaged with the cover engagement portion to position the biasing member adjacent the filter element to bias the filter element in the longitudinal direction.  
         [0007]     In yet another aspect, the invention provides a cover for use with an engine filter base and a filter element. The cover comprising a shell, a biasing element integrally formed as one piece with the shell, and an attachment member integrally formed as one piece with the shell. The attachment member is adapted to engage the filter base such that the filter element is sandwiched between the biasing element and the filter base.  
         [0008]     The biasing element accounts for variations and tolerances in the various components that make up the air cleaner so that when the cover and the base attach to one another, they firmly clamp the filter element and inhibit rattling. In addition, the biasing element assures that contact between the base and the filter element is sufficient to maintain a seal therebetween.  
         [0009]     Additional features and advantages will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The detailed description particularly refers to the accompanying figures in which:  
         [0011]      FIG. 1  is a perspective view of a rototiller including an engine;  
         [0012]      FIG. 2  is a perspective view of the engine of  FIG. 1  including an air cleaner assembly;  
         [0013]      FIG. 3  is an exploded perspective view of the filter assembly of  FIG. 2 ;  
         [0014]      FIG. 4  is a sectional view of a filter assembly cover and a filter element;  
         [0015]      FIG. 5  is a sectional view of a filter base with a biasing portion;  
         [0016]      FIG. 6  is a sectional view of a filter assembly base and the filter element;  
         [0017]      FIG. 7  is a top view of another air cleaner cover;  
         [0018]      FIG. 7   a  is a section view taken along line A-A of  FIG. 7 ;  
         [0019]      FIG. 8  is a top view of another air cleaner cover;  
         [0020]      FIG. 8   a  is a section view taken along line A-A of  FIG. 8 ;  
         [0021]      FIG. 9  is a top view of another air cleaner cover; and  
         [0022]      FIG. 9   a  is a section view taken along line A-A of  FIG. 9 . 
     
    
     DETAILED DESCRIPTION  
       [0023]     Engines of the type described herein are well-suited to use as the source of power for outdoor power equipment such as lawn and garden maintenance equipment. One such piece of equipment, a rototiller  10  is illustrated in  FIG. 1  as an example. The rototiller  10  includes an engine  15  with an air cleaner  20 . The engine  15  powers the rotating blades of the rototiller  10  to till soil. Many other types of equipment may use similar engines  15  (e.g., lawnmowers, power augers, edgers, log-splitters, string-trimmers, chipper/shredders, snow throwers, pressure washers, and generators). Therefore, the invention described herein should not be limited to use with engines  15  attached to rototillers  10 .  
         [0024]     With reference to  FIG. 2 , the engine  15 , including the air cleaner  20 , is illustrated in greater detail. The air cleaner  20  is positioned to receive dirty air from the atmosphere and deliver clean filtered air to a carburetor (not shown) or other component for use in combustion. The engine  15  also includes a fuel tank  25  that stores fuel. The fuel from the fuel tank  25  flows to the carburetor and mixes with filtered air from the air cleaner  20  to produce the combustible mixture. The combustible fuel-air mixture then flows to one or more cylinders for combustion.  
         [0025]     The air cleaner  20 , shown in  FIG. 3  and sometimes referred to herein as an air filter assembly or a filter device, includes a base  30 , a cover  35 , and a filter element  40 . The cover  35  attaches to the base  30  to define a filter space  45 . The filter space  45  is sized and shaped to receive and support the filter element  40  during engine operation. In most constructions, the base  30  and cover  35  are each formed from a plastic material that is injection molded in a single operation using a two-cavity mold. However, other constructions may use other materials (e.g., thermosetting plastic, composite, metal, ceramic, and the like) as well as other manufacturing processes (e.g., molding, casting, drawing, cold forming, fabrication, and the like). It should be noted that other constructions may employ a single piece filter device. As such, the filter device should not be limited to the foregoing arrangement.  
         [0026]     The filter element  40 , illustrated in  FIGS. 3 and 4 , includes a pleated paper filter media  50  sandwiched between an upper end cap  55  and a lower end cap  60 . The filter element  40  is generally oval and includes a hollow opening  65  that extends from an inner surface  70  of the upper end cap  55  through the lower end cap  60 . Filter elements  40  of this type are common in similar engines as well as in other internal combustion engines. Many different types of filter elements as well as different shapes of filter elements will also function with the present invention. For example, round, square, or rectangular filter elements will function with the present invention. As such, the air cleaner  20  should not be limited to oval filter elements  40  or pleated filter media  50 .  
         [0027]     The base  30 , illustrated in  FIGS. 3 and 6 , includes a substantially flat platform  75  that supports a filter standoff  80 . The filter standoff  80  extends in a perpendicular direction from the flat platform  75 . The lower end cap  60  rests on top of the standoff  80  such that the hollow opening  65  of the filter element  40  is spaced a distance above the flat platform  75 . Thus, filtered air freely exits the filter element  40  and exits the air cleaner  20  through an air outlet aperture  90  formed in the flat platform  75 .  
         [0028]     The air outlet aperture  90  is provided in the base  30  to allow for the escape of the filtered air. The air outlet aperture  90  is a hole in the base  30  that provides a fluid path from the hollow opening  65  of the filter element  40  out of the air cleaner  20 . In most applications, the outlet aperture  90  will directly or indirectly connect to the carburetor to allow for the delivery of filtered air.  
         [0029]     The flat platform  75  also supports attachment pedestals  95  that include attachment apertures  100  that engage the cover  35  to attach the cover  35  to the base  30 . The attachment apertures  100  are substantially rectangular openings in the attachment pedestals  95 . The construction of  FIG. 3  includes two attachment pedestals  95 . Other constructions may include a single attachment pedestal  95  or three or more as may be required by the particular application. In other constructions, the attachment apertures  100  may be formed in the flat platform  75 , thus requiring no attachment pedestals  95 .  
         [0030]     The cover  35 , illustrated in  FIGS. 3 and 4 , includes a biasing portion  105 , two tab members  110  (one shown), and a plurality of vent apertures  115 . The vent apertures  115  include several square openings that are positioned to provide for the flow of air into the cover  35 . In most constructions, apertures  115  are located on two sides of the cover  35 , with some constructions including apertures  115  on all four sides of the cover  35 . Furthermore, while several square apertures  115  are illustrated, it should be understood that any number of apertures  115  of any shape will function as desired, so long as the apertures  115  provide sufficient flow area for the admission of air into the air cleaner  20 .  
         [0031]     Each tab member  110  includes a hook portion  120  that is attached to the cover  35  by a cantilevered extension  125 . The cantilevered extension  125  allows the hook portion  120  to be moved from an engaged position to a disengaged position. In the engaged position, the hook portion  120  attaches the cover  35  to the base  30  by engaging the attachment pedestal  95  adjacent the attachment apertures  100 . To connect or disconnect the cover  35 , the user presses the tab members  110  into their disengaged position (toward the interior of the cover  35 ). In the disengaged position, the hook portions  120  pass freely through the attachment apertures  100  in the attachment pedestals  95 . Both tab members  110  are positioned to allow the cover  35  to be in a desired position relative to the base  30  when the two components are attached to one another. In constructions in which the base  30  includes attachment pedestals  95 , the tab members  110  extend only a portion of the height of the cover  35 . In constructions that do not include pedestals  95 , the tab members  110  and hook portions  120  extend beyond a lowermost edge  130  of the cover  35 .  
         [0032]     The biasing portion  105 , best illustrated in  FIGS. 3 and 4 , includes a leaf spring  133  that is integrally formed as part of a top surface  135  of the cover  35 . Two slots  140  are formed in the top surface  135  of the cover  35  to allow the leaf spring  133  to move in a direction that is substantially perpendicular to the plane of the top surface  135 . In many constructions, the slots  140  are formed during the molding process. However, other constructions include finishing steps that occur after the initial molding of the part that may include the addition of the slots  140 .  
         [0033]     As shown in  FIG. 4 , the leaf spring  133  extends into the filter space  45  to contact the upper end cap  55  before the cover  35  engages the base  30 . As the cover  35  is moved toward the engaged position, the leaf spring  133  deflects to compress and retain the filter element  40 . In addition, the two tab members  110  deflect inwardly as they contact the attachment pedestals  95  adjacent the attachment apertures  100 . Once the hook portions  120  clear the attachment apertures  100 , the tab members  110  return to their free position such that the hook portions  120  engage the pedestals  95  adjacent the attachment apertures  100 , thereby attaching the cover  35  to the base  30 . The biasing portion  105  allows the air cleaner  20  to compensate for variations in filter element height, hook position, pedestal height, and/or other manufacturing tolerances that may arise in the manufacturing or assembly process, or due to wear after use.  
         [0034]     To disassemble the air cleaner  20 , the user moves the hook portions  120  toward the center of the air cleaner  20  and pulls the cover  35  away from the base  30 . The hook portions  120  pass through the attachment apertures  100  and the cover  35  disengages from the base  30 .  
         [0035]     It should be understood that only one possible system for the attachment of the cover  35  to the base  30  has been described with many other systems being possible. For example, other constructions may locate the attachment apertures in the cover and the hook members in the base.  
         [0036]     One of ordinary skill will realize that there are many different arrangements of the cover  35  and/or base  30  that include an integrally-formed biasing portion  105 .  FIG. 5  illustrates one example in which the biasing portion  105   a  includes an annular cantilevered ring  145  formed as part of the base  30   a . The filter element  40  sits on top of the ring  145 , which compresses when the cover is attached to the base  30   a . In this construction, a collar  150  surrounds the perimeter of the filter element  40  to maintain the filter element  40  in the proper position. In still other constructions, a cantilevered waved-ring (similar to a wave washer) may be integrally formed with the base.  
         [0037]     Another example, illustrated in  FIGS. 7 and 7   a , includes a cantilevered biasing member  105   b  formed as part of the top  135   b  of the cover  35   b . The cantilevered portion  105   b  is disconnected from the cover  35   b  along three edges  155  such that it projects into the filter space  45  inside of the cover  35   b  in the free state. The cantilevered portion  105   b  contacts the filter element (not shown) and deflects when the cover  35   b  is attached to the base (not shown).  
         [0038]      FIGS. 8 and 8   a  illustrate another construction in which a biasing member  105   c  is formed in a spiral shape. A spiral cut  160  in the top  135   c  of the cover  35   c  forms a spiral arm  165  that extends into the filter space  45  of the cover  35   c  where it can contact the filter element (not shown) when the cover  35   c  is attached to the base (not shown).  
         [0039]     In yet another variation illustrated in  FIGS. 9 and 9   a , a biasing element  105   d  is formed to include two cantilevered portions  170  that extend into the filter space  45 . The two cantilevered portions  170  contact the filter element (not shown) when the cover  35 d is attached to the base (not shown) and function much the same as the previous biasing elements.  
         [0040]     As should be clear, many other biasing members are possible. As such, the invention should not be limited to those few examples described herein.  
         [0041]     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.