Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a divisional application of U.S. Ser. No. 09/981,053, filed on Oct. 16, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention generally relates to power edgers and more particularly to a housing assembly for housing the blade member of a power edger.  
         BACKGROUND OF THE INVENTION  
         [0003]    Powered edgers having a rotary blade for performing an edging operation require routine maintenance in that the rotating blade is subject to wear and must be periodically sharpened or replaced. Furthermore, debris, such as grass and dirt, tend to accumulate on the guard around the blade and must be removed in order to maintain the efficiency and effectiveness of the edger device.  
           [0004]    Typical housing assemblies for rotary edgers include a screw-attached guard plate that must be removed from a housing in order to gain access to the blade or to remove accumulated debris. In addition to being inconvenient, these conventional housing assemblies frequently do not thoroughly seal against the housing such that dirt and debris have been known to infiltrate in an undesired manner around the guard plate.  
           [0005]    Accordingly, there remains a need in the art for an improved housing assembly for a power edger. The improved housing assembly is preferably highly resistant to the infiltration of debris around an access door and includes a guard that is more resistant to the accumulation of debris.  
         SUMMARY OF THE INVENTION  
         [0006]    In one preferred form, the present invention provides a housing assembly for an edger. The housing assembly includes a housing, a door that is pivotably coupled to the housing, a latch mechanism and a latch receiving structure. The latch mechanism is coupled to one of the housing and the door and includes a latch member and a biasing device. The biasing device is coupled to the latch member and is operable for biasing the latch member in a predetermined biasing direction toward a predetermined neutral position. The latch receiving structure is coupled to the other one of the housing and the door and includes a ramp portion and a latch aperture. The ramp portion tapers downwardly toward the latch aperture and is configured to contact the latch member when the door is rotated toward the housing and cause the latch member tp rotate in a direction opposite the biasing direction so that the latch member is positioned into alignment with the latch aperture.  
           [0007]    In another preferred form, the present invention provides an edger including a blade, a power source that is configured to selectively provide rotary power to the blade, and a housing assembly that is associated with the power source. The housing assembly associated defines a blade cavity in which the blade is mounted and includes a housing, a cover, a latch mechanism and a latch receiving structure. The cover is pivotably mounted to the housing and movable between a closed condition and an open condition. The latch mechanism is coupled to the cover and includes a latch member, which is movable between a latched position and an unlatched position, and a spring, which biases the latch member into the latched position. The latch receiving structure is coupled to the housing and includes a latch aperture, which is configured to receive the latch member therethrough only when the latch member is positioned in the unlatched position, and a ramp. The ramp is tapered so that when the cover is rotated toward the housing, contact between the ramp and the latch member moves the latch member into the unlatched position and into alignment with the latch aperture.  
           [0008]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, wherein:  
         [0010]    [0010]FIG. 1 is a perspective view of a power edger having a housing assembly that is constructed in accordance with the teachings of the present invention;  
         [0011]    [0011]FIG. 2 is a perspective view of the power edger of FIG. 1 illustrating the door in an open condition;  
         [0012]    [0012]FIG. 3 is a perspective view of a portion of the power edger of FIG. 1 illustrating the housing in greater detail;  
         [0013]    [0013]FIG. 4 is an enlarged perspective view of a portion of the housing illustrating the latch securing structure in detail;  
         [0014]    [0014]FIG. 5 is a partial sectional view taken along the line  5 - 5  of FIG. 1;  
         [0015]    [0015]FIG. 6 is a perspective view of a portion of the power edger of FIG. 1 illustrating the door in greater detail;  
         [0016]    [0016]FIG. 7 is an exploded perspective view of a portion of the power edger of FIG. 1 illustrating the latch mechanism in greater detail; and  
         [0017]    [0017]FIG. 8 is a partial exploded perspective view of the power edger of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    With reference to FIGS. 1 and 2 of the drawings, an edger  8  is illustrated to include a housing assembly  10 , which has been constructed in accordance with the teachings of the present invention. The edger  8  is also shown to include a shroud  20 , a rotary power source  22 , front and rear wheels  24  and  26 , respectively, a blade  28  and a handle  30 . The shroud  20  conventionally houses the rotary power source  22  and serves as the means by which the front and rear wheels  24  and  26  and the handle  30  are coupled to the rotary power source  22 . In the particular embodiment illustrated, the shroud  20  is an integrally formed portion of the housing assembly  10 , but those skilled in the art will understand that the housing assembly  10  may be discrete and separate from other portions of the edger  8 , including those that house a rotary power source. The rotary power source  22  is illustrated to be an electric motor in the example provided and includes an output shaft  34  that is rotatable about a rotary axis  36 . The blade  28  is fixedly but removably coupled to the output shaft  34  such that it is rotatable about the rotary axis  36 . At least one of the front and rear wheels  24  and  26  is preferably movably coupled to the shroud  20  of the housing assembly  10  to permit the height of the blade  28  to be adjusted relative to the ground. The handle  30  is coupled to the shroud  20  via an attachment socket  38  that is integrally formed into the shroud  20 .  
         [0019]    The housing assembly  10  is also illustrated to include a housing  40 , a door  42 , a hinge pin  44  and a latch mechanism  46 . With reference to FIGS. 2 and 3, the housing  40  includes a first wall member  50 , a guard  52 , a latch securing structure  54 , a first labyrinth member  56  and a first hinge structure  58 . The housing  40  defines a blade cavity  60  in which the blade  28  is rotatably disposed and a generally vertical portion  62  that is oriented generally perpendicular the rotary axis  36  of the output shaft  34 .  
         [0020]    The guard  52  extends generally perpendicularly from the first wall member  50  in a direction that is generally parallel the rotary axis  36  such that the guard  52  bounds the outer perimeter of the blade cavity  60 . The guard  52  is illustrated to include a confronting portion  68  having a leading end  70  at the forward end of the housing  40  and a trailing end  72  that is located rearwardly of the leading end  70 . The confronting portion  68  is defined by an angle of at least 90° and preferably by an angle of at least 120°. The confronting portion  68  is also characterized by a radius  74  that is centered at a point along the rotary axis  36 . The radius  74  is not constant, but rather increases in a smooth manner in the direction in which the blade  28  rotates between a leading end  70  and a trailing end  72 . The increasing sweep of the radius  74  therefore provides an increasing amount of clearance between the tip  28   a  of the blade  28  and the inner surface  68   a  of the guard  52  between the leading end  70  of the confronting portion  68  and the trailing end  72  of the confronting portion  68 . Preferably, the amount of clearance between the leading end  70  and the trailing end  72  increases by a factor of between about 2 to about 10. Those skilled in the art will understand that while the rate by which the radius  74  increases may correspond to any mathematical model, the rate by which the radius  74  increases is dependent upon numerous considerations, including the maximum overall size of the housing assembly  10  and the capability of the blade  28  to circumferentially shed the dirt and debris encountered by the blade  28  during the operation of the edger  8 .  
         [0021]    In the particular embodiment illustrated, the guard  52  is shown to include a trailing portion  78  that is coupled to the trailing end  72  of the confronting portion  68 , extending therefrom in a direction that is generally tangent the radius  74  at the trailing end  72 . The trailing portion  78  is configured to maintain an increasing amount of clearance between the guard  52  and the tip  28   a  of the blade  28  while permitting the overall size of the housing assembly  10  to be maintained within a predetermined size envelope. In this regard, the trailing portion  78  extends rearwardly by an amount that is relatively smaller than the amount the confronting portion  68  otherwise would have extended had the radius  74  been extended downwardly to the bottom edge of the housing  40 .  
         [0022]    The extremely smooth configuration of the inner surface  68   a  of the guard  52  generally, and of the confronting portion  68  in particular, tends to resist the build-up of dirt and debris that is centrifugally directed at the housing assembly  10  by the rotation of the blade  28 . As such, the frequency and/or duration of routine cleaning events are reduced as compared with other known edger housing assemblies.  
         [0023]    The latch securing structure  54  is illustrated to be integrally formed with a forward portion of the housing  40 . The latch securing structure  54  includes a ramp portion  80 , a first debris collar  82  and a latch aperture  84 . In the example provided, the ramp portion  80  is formed on a helix having an axis that is generally parallel the axis  36 . The helix has an inner most point  88  that is positioned on a side of the latch aperture  84  and an outer most point  90  that is rotated in a counterclockwise direction relative to the inner most point  88 . The first debris collar  82  surrounds both the ramp portion  80  and the latch aperture  84 , extending generally perpendicularly from the forward portion of the first wall member  50 . In the particular example provided, the latch aperture  84  is illustrated to have a key-hole shape that includes a cylindrical portion  92  and a slotted portion  94 .  
         [0024]    With reference to FIGS. 3 and 5, the first labyrinth member  56  is a generally L-shaped structure that is coupled to at least a portion of the outer perimeter of the first wall member  50 . The first labyrinth member  56  includes a base portion  100 , which extends from the first wall member  50 , and a leg portion  102  that extends generally perpendicular to the base portion  100 . The first labyrinth member  56  is spaced radially outwardly from the guard  52  and in the particular embodiment illustrated, does not extend outwardly from the generally vertical portion  62  of the first wall member  50  to the same extent as the guard  52 .  
         [0025]    With renewed reference to FIGS. 2 and 3, the first hinge structure  58  is located rearwardly of the guard  52  and includes first and second hinge bosses  110  and  112 , respectively. Each of the first and second hinge bosses  110  and  112  extends generally perpendicularly from the generally vertical portion  62  of the first wall member  50 . A hinge pin aperture  114  extends completely through the first hinge boss  110  and partially through the second hinge boss  112 . The first hinge boss  110  also includes a slotted tab aperture  116  that intersects the hinge pin aperture  114 .  
         [0026]    With reference to FIGS. 2 and 6, the door  42  is illustrated to include a second wall member  118 , a guard lip  120 , a second labyrinth member  122 , a latch housing structure  124  and a second hinge structure  126 . The second wall member  118  is sized to cover the open end of the housing  40  and includes a generally vertically extending structure  128  that is configured to abut a side of the blade cavity  60  opposite the first wall member  50 . The guard lip  120  is coupled to the generally vertically extending structure  128  and extends generally perpendicularly therefrom. The inner edge  129  of the guard lip  120  is configured to mirror the outer edge  130  of the guard  52  (FIG. 5).  
         [0027]    With additional reference to FIG. 5, the second labyrinth member  122  is coupled to at least a portion of an outer edge of the second wall member  118 . In the embodiment illustrated, the second labyrinth member  122  is generally U-shaped, having a pair of furcations  144  that extend generally perpendicular the generally vertically extending structure  128  are which are spaced apart from one another to define a void  146  therebetween.  
         [0028]    With renewed reference to FIGS. 2 and 6, the latch housing structure  124  is illustrated to be formed into a forward portion of the door  42 . An aperture  150 , similar in configuration and size to the latch aperture  84  formed in the housing  40 , extends through the second wall member  118 . A second debris collar  152  extends circumferentially around the aperture  150  on the inner side of the second wall member  118 . A collar (not specifically shown) is formed on the outer side of the second wall member  118  radially outwardly of the aperture  150 .  
         [0029]    With reference to FIG. 7, the latch mechanism  46  is illustrated to include a knob  160  and a spring  162 . In the particular embodiment illustrated, the knob  160  includes a grip portion  166 , a spindle  168  and a latch member  170 . The grip portion  166  includes a flange member  172  and is configured to receive a rotary input from the thumb and forefinger of the operator of the edger  8 . The flange member  172  forms a relatively large surface which supports the loads that are exerted onto the knob  160  by the spring  162  and the operator of the edger  8 . The flange member  172  is sized larger than the aperture  150  so as to prevent the knob  160  from being pushed completely through the door  42 . The spindle  168  is fixedly coupled to the grip portion  166  at a first end and to the latch member  170  at a second end. In the example provided, the spindle  168  is sized to rotate within the cylindrical portions  92  of the latch aperture  84  and aperture  150  that are formed into the housing  40  and the door  42 , respectively. An attachment aperture  176  is formed through the spindle  168  proximate the flange member  172  on an axis that is generally perpendicular to the longitudinal axis of the spindle  168 . The latch member  170  extends generally perpendicularly the longitudinal axis of the spindle  168  and is sized to be received through the slotted portion  94  of the latch aperture  84  and aperture  150 .  
         [0030]    The spring  162  is illustrated to be a combination torsion and tension spring having first and second end members  180  and  182 , respectively. The first end member  180  is configured to engage a portion of the knob  160 , while the second end member  182  is configured to engage the door  42 . The spring  162  fits over the collar that is formed on the outer surface of the door  42 ; the collar serves to position the spring  162  in a radial direction relative to the aperture  150 . In the example provided, the first end member  180  is a post that extends through the attachment aperture  176  that is formed through the spindle  168  while the second end member  182  is generally U-shaped, being configured to extend partially through the slotted portion  94  of the aperture  150  and engage the second wall member  118 . The torsional aspect of the spring  162  biases the knob  160  in a predetermined rotational direction, which, in the particular embodiment illustrated, is counterclockwise, when looking at the outer surface of the door  42 , such that the knob  160  is positioned toward a neutral position as shown in FIG. 1. The tension aspect of the spring  162  generates a biasing force that tends to push the knob  160  inwardly toward the outer surface of the door  42 .  
         [0031]    With renewed reference to FIGS. 2 and 6, the second hinge structure  126  extends outwardly from the second wall member  118 , being sized in length to fit between the first and second hinge bosses  110  and  112  on the housing  40 . A hinge pin aperture  188  that is sized to receive the generally cylindrically shaped hinge pin  44  extends through the second hinge structure  126 . As shown in FIG. 8, the door  42  is coupled to the housing  40  such that the second hinge structure  126  is disposed between the first and second hinge bosses  110  and  112  and the hinge pin  44  is inserted into the hinge pin apertures  114  and  188 . A retaining tab  190  is inserted into the slotted tab aperture  116  in the first hinge boss  110  to prevent the hinge pin  44  from becoming dislodged from the hinge pin apertures  114  and  188 .  
         [0032]    Once coupled by the hinge pin  44 , the door  42  is pivotally coupled to the housing  40  about an axis that is defined by the hinge pin  44 . The door  42  is movable between a closed position, as illustrated in FIG. 1, and an open condition, as illustrated in FIG. 2. With reference to FIGS. 2, 4 and  7 , as the door  42  is rotated from the open position to the closed position, the side of the latch member  170  on the knob  160  is brought into contact with the ramp portion  80  that is formed into the latch securing structure  54  of the housing  40 . Further rotation of the door  42  about the hinge pin  44  toward the housing  40  causes the latch member  170  to both slide along the ramp portion  80  and rotate in a rotational direction opposite the biasing direction of the spring  162 . When the door  42  has been closed sufficiently to align the latch member  170  to the slotted portion  94  of the latch aperture  84 , the force applied by the spring  162  causes the latch member  170  and a portion of the spindle  168  to shoot through the latch aperture  84 . The knob  160 , no longer being constrained by the ramp portion  80 , thereafter rotates in the predetermined biasing direction in response to the torsional biasing aspect of the spring  162  to rotate the latch member  170  relative to the slotted portion  94  of the latch aperture  84  so that the latch member  170  is no longer aligned to the slotted portion  94  of the latch aperture  84 . From the foregoing, it will be apparent to those skilled in the art that the operator of the edger  8  need not manipulate any portion of the latch mechanism  46  to latch the door  42  to the housing  40 . Rather, all that is needed to actuate the latch mechanism  46  to latch the door  42  to the housing  40  is to rotate the door  42  and the housing  40  together.  
         [0033]    With reference to FIG. 5, when the door  42  is placed in a closed position, the guard lip  120  is illustrated to engage the outer perimeter of the guard  52  and the leg portion  102  of the first labyrinth member  56  is shown to engage the void  146  between the furcations  144  of the second labyrinth member  122 . As thus configured, the first and second labyrinth members  56  and  122  cooperate when the door  42  is in the closed position to form a labyrinth seal  200  around at least a portion of the housing assembly  10  that inhibits dust and debris from exiting the housing assembly  10 . Further, the guard lip  120  and guard  52  cooperate to form a secondary seal  202  that is located radially inwardly of the labyrinth seal  200 . The secondary seal  202  additionally assists in inhibiting the transmission of dust and debris outwardly of the housing assembly  10 . The secondary seal  202  also tends to inhibit the transmission of dust and debris to other portions of the housing assembly  10 , such as the first and second hinge structures  58  and  126  and the latch mechanism  46 .  
         [0034]    With reference to FIGS. 4 and 7, when the door  42  is positioned in the closed position, the first and second debris collars  82  and  152  engage or nest to form a supplemental debris guard (not specifically shown) around the latch mechanism  46 . The supplemental debris guard tends to inhibit the transmission of any dirt and debris that are expelled past the secondary seal  202  into the latch mechanism  46 .  
         [0035]    While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the foregoing description and the appended claims.

Technology Category: 1