Abstract:
An implement for trimming grass and weeds, and for blowing clippings and debris. The implement consists of a rotatable housing having an outer wall; at least two fan blades, each of the fan blades having an inner end and a outer end; and at least two slide channels interconnecting each of the fan blades with the rotatable housing. The slide channels allow the outer ends of the fan blades to alternately extend from the outer wall of the rotatable housing to a fully extended position, and retract toward said outer wall to a fully retracted position. A weed trimming line is fixedly attached to and extends outwardly from the rotatable housing for performing weed trimming as a function in addition to debris blowing.

Description:
FIELD OF THE INVENTION 
     This invention relates to electric and gas powered weed and brush trimmers. More particularly, this invention relates to such trimmers adapted for alternately serving as a grass and debris blower. 
     BACKGROUND OF THE INVENTION 
     The adaptation of a weed cutting or trimming implement to alternately or simultaneously blow grass and debris is taught by U.S. Pat. No. 5,345,788 issued Sep. 13, 1994, to Jerry; disclosing a steel blade having air driving fins protruding therefrom. A similar adaptation of a grass or weed cutting blade is taught by U.S. Pat. No. 5,233,820 issued Aug. 10, 1993, to Willsie. In another expression of the concept, U.S. Pat. No. 4,827,702 issued May 9, 1999, teaches a rotatable flexible line trimmer having a fan blade ring removably attached to its rotatable trimmer head. Adaptations of weed or grass cutting blades to propel air for debris removal are undesirable because the air propelling function dissipates power needed for cutting. Adaptations of line trimmer heads to include attachable and detachable air propelling blades are similarly undesirable because detachable fan blades may be lost or misplaced, and attachment and detachment steps are inconvenient and cumbersome. 
     The instant invention overcomes the disadvantages described above by providing a weed trimmer head having alternately extendable and retractable fan blades; the trimmer head thereby allowing, upon retraction of the fan blades, full rotary power to be applied to a weed cutting element; and alternately allowing, upon extension of the fan blades, air sweeping of debris from sidewalks and curbs. 
     BRIEF SUMMARY OF THE INVENTION 
     The instant inventive trimmer-blower preferably comprises a cylindrical housing having an upper wall or ceiling spanning across its upper end. The upper surface of the upper wall is preferably adapted for attachment to the drive linkage of an electric or gasoline powered handheld or shoulder mounted weed and grass trimmer. Where the drive linkage of such trimmer comprises a spirally threaded lug, an internally spirally threaded nut embedded axially within and extending upwardly from said upper wall is preferably utilized as the attaching means. A steel ring or collar, through which a threaded bolt upwardly passes, may alternately be utilized where the trimmer includes a female drive linkage. 
     The above described cylindrical rotatable housing preferably defines a downwardly opening cylindrical space within which at least two fan blades are slidably mounted for alternate outward extension and inward retraction. Preferably, slide channels for guiding the fan blades&#39; outward extension and inward retraction are fixedly situated within the housing. Also preferably, the channels comprise a series of slide stopping or slide resisting walls and ridges for selectively holding the fan blades in their extended or retracted positions within the housing. 
     Preferably, the downward opening of the cylindrical space is closed by a removably attached lower wall, the upper surface of such lower wall providing lower slide surfaces of the slide channels. 
     Preferably, the housing has weed trimmer line or blade extending means integral with the lower wall or lower side wall of the housing; such means being positioned below the blades, allowing the implement to be alternately utilized for grass and debris blowing and for weed trimming. 
     Accordingly, it is an object of the present invention to provide a rotatable weed trimmer head which is adapted for alternately blowing grass clippings and debris. 
     It is a further object of the present invention to provide such an implement having alternately extendable and retractable air propelling fan blades. 
     Other and further objects, benefits, and advantages of the present invention will become known to those skilled in the art upon review of the Detailed Description which follows, and upon review of the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of the present inventive weed trimming and debris blowing implement. 
     FIG. 2 is a plan view of the undersurface of the implement depicted in FIG. 1, the view showing fan blades in their retracted positions. 
     FIG. 3 is a sectional view as indicated in FIG. 1, the view of FIG. 3 showing trimmer line removed and showing fan blades repositioned. 
     FIG. 4 is a view of the internal workings of the implement, such workings being exposed through detachment of the lower wall of the housing. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and in particular to FIG. 1, the present inventive weed and grass trimming and debris blowing implement is referred to generally by Reference Numeral  1 . The implement has a circular upper wall  4  and an annular upper side wall or outer wall  2  extending downwardly from the upper wall  4 . An annular lower side wall or outer wall  6  removably extends downwardly from the lower end of the upper side wall  2 . Referring simultaneously to FIGS. 2 and 3, a circular lower wall  32  spans across the upper end of the lower side wall  6 , the lower wall  32  having a pair of flexible hooks  22  and  20  extending upwardly therefrom. Referring simultaneously to FIGS. 1,  3  and  4 , the hooks  20  and  22  provide a detaching means allowing the lower wall  32  and lower side wall  6  to be alternately detached from and reattached to the upper wall  4  and upper side wall  2 . The upper ends of the hooks  22  and  24  extend respectively through apertures  24  and  26  to engage with and latch the upper surface of the upper wall  4 . By manually inwardly pressing the upper ends of hooks and  22  and  20 , such hooks disengage, allowing the lower floor  32  and lower side wall  6  to fall away from the upper assembly of the implement  1 . The reverse of the above steps reattaches the lower side wall  6  and lower floor. 
     Referring again to FIG. 1, the upper surface of the upper wall  4  preferably has a hollow cylindrical sleeve  12  molded as a part thereof and extending axially upward therefrom. A spirally threaded nut  16  is preferably fixedly embedded within the bore of the sleeve  12 , the spirally threaded nut  16  providing means for attachment of the implement to the drive linkage of a gas powered or electric powered handheld or shoulder mounted weed trimmer. To provide structural rigidity to the sleeve  12 , braces  14  are preferably molded integrally with the sleeve  12  and the upper wall  4 . Referring simultaneously to FIGS. 1 and 4, where the drive linkage of the weed trimmer comprises a threaded aperture, as opposed to a threaded lug, the implement  1  may be attached by extending a spirally threaded bolt upwardly through aperture  58  for threaded mounting within the drive linkage of the weed trimmer. 
     Referring simultaneously to FIGS. 1,  2 , and  3 , a preferred embodiment of the implement  1  comprises a length of heavy gauge monofilament plastic line  18  which serves as a weed trimming member. The line  18  preferably extends as depicted through aperture  38  within the lower side wall  6 , thence through apertures  42  within string retaining tab  34 , and thence through aperture  40  within the lower side wall  6 . Upon rapid rotation of the implement  1  while line  18  is so installed, the line  18  may perform weed and grass cutting without lateral slippage through apertures  38 ,  40 , or  42 . While the line retaining and extending structure depicted in FIG. 2 is preferred for its durability and simplicity, numerous other line retaining and extending mechanisms may be utilized. For example, within the space defined by the lower side wall  6  and lower floor  32 , a monofilament line advancing spool may be installed. As a further alternative, pivoting plastic grass cutting blades may be installed upon the housing in place of the flexible line  18 . Also alternately, pivoting or fixed steel blades may be utilized. Utilization of the flexible heavy gauge monofilament line  18  is preferred due to enhanced safety and due to cost economies. 
     Referring again to FIG. 1, fan blades  8  and  10  are outwardly extendable through apertures  28  from the outer surface of the upper side wall  2 . Alternately, the fan blades may be slidably retracted into the interior space of the housing; such space being defined by the upper side wall  2 , the upper wall  4 , and, referring to FIG. 3, the lower wall  32 . Full retraction of the fan blades  8  and  10  positions them as depicted in FIG. 2, allowing the line  18  to perform its grass and weed cutting function without interference or power reduction. 
     Referring simultaneously to FIGS. 3 and 4, fan blades  8  and  10  respectively slidably move within slide channels  60  and  62 . Referring additionally to FIG. 1, sliding contact between fan blades  8  and  10  and the housing occurs between the outer surfaces of the fan blades  8  and  10  and the inner surfaces of apertures  28 . Sliding contact also occurs between the outer surfaces of the enlarged bases  44  and  46  of fan blades  10  and  8 , and the upper and lower slide surfaces of the slide channels  62  and  60 ; the downwardly facing surface of the upper wall  4  and the upwardly facing surface of the lower wall  32  providing such slide channel slide surfaces. 
     Referring further to FIGS. 3 and 4, the inwardly facing surface of the upper side wall  2  in combination with slide stops  56  and  70  prevent outward sliding motion of the fan blades  10  and  8  when such blades are in their fully extended positions. Similarly, slide stops  72  and  74  prevent the fan blades  10  and  8  from sliding inwardly beyond their fully retracted positions. In order to prevent fan blades  8  and  10  from freely sliding away from their fully retracted positions, convex protrusions or ridges  36  and  68  preferably extend downwardly into the slide channels  60  and  62  from the lower surface of the upper wall  4 . Similarly, in order to prevent fan blades  8  and  10  from freely sliding away from their fully extended positions, convex protrusions or ridges  66  and  48  preferably similarly extend downwardly from the lower surface of the wall  4 . Walls  50 ,  76 ,  64 , and  54  are preferably integrally molded with the wall  4 , serving as slide guides of the slide channels  60  and  62 . Walls  50 ,  76 ,  64 , and  54  prevent the enlarged ends  46  and  44  of the fan blades  8  and  10  from sliding laterally within slide channels  60  and  62 . 
     Operation of the inventive implement  1 , referring simultaneously to all figures, typically begins with fan blades  8  and  10  in their fully retracted positions. As depicted in FIG. 4, upon application, for example, of manual inward pressure to the outer end of fan blade  10 , its enlarged end  44  may be driven over and past ridge  48 , allowing the fan blade  10  to freely inwardly slide until the enlarged end  44  comes into contact with ridge  68 . The manual pressure may then be increased to drive the enlarged end  44  over ridge  68 , fixedly positioning the fan blade  10  in its fully retracted position. With fan blades  8  and  10  fully retracted and with a monofilament line  18  installed as depicted in FIG. 2, weed trimming or lawn edging may proceed unimpeded by the fan blades  8  and  10 . Due to the weight of the enlarged ends  46  and  44 , centrifugal force applied to the fan blades  8  and  10  while they are in their fully retracted positions, tends to hold the fan blades in such positions rather than driving them outwardly. 
     Performance of weed and grass trimming through rapid rotation of line  18  depicted in FIG. 2 will typically undesirably leave clippings and debris on sidewalk and curb surfaces. In order to utilize the implement  1  as a debris sweeping blower, the outer ends of fan blades  8  and  10  may be manually grasped so that the thumb and index finger of an operator&#39;s hand come into frictional contact with friction grooves  30  which are preferably molded into the upper and lower surfaces of the outer ends of fan blades  8  and  10 . Manual pulling forces are then successively applied to fan blades  8  and  10 , pulling the enlarged ends  44  and  46  thereof over ridges  36 ,  48 ,  66 , and  68  until the blades reach their fully extended positions. While the fan blades  8  and  10  are in their fully extended positions, ridges  48  and  66  prevent such blades from freely sliding inwardly upon cessation of centrifugal force. As can be seen in FIG. 3, the fan blades  8  and  10  are preferably tilted at an angle, preferably between 30° and 45°, with respect to the axis of rotation of the implement  1 . Such tilting of the fan blades  8  and  10  allows them to act as air foils, propelling air downwardly upon clockwise rotation of the implement  1 . Such downwardly driven air efficiently blows and sweeps grass clippings and debris from sidewalk and curb surfaces. 
     After prolonged use of the implement  1 , dust or dirt may accumulate within the slide channels  60  and  62 , preventing the fan blades from smoothly extending and retracting. Also, through use, the fan blades  8  and  10  may become broken or damaged. Accumulation of dirt or occurrence of blade damage gives rise to a need for internal maintenance of the implement  1 . Referring to FIG. 1, thumb pressure may be inwardly applied to the outwardly facing surfaces of hooks  20  and  22  driving the hooks inwardly within apertures  24  and  26 . Upon pressing hooks  20  and  22  inwardly, the lower wall  32  may be removed, allowing removal of fan blades  8  and  10 . After performance of interior cleaning or blade replacement, reversal of the disassembly steps reconfigures the implement  1  for use. 
     Preferably, all components of the implement  1  other than the nut  16  are fabricated through a plastic injection molding process. Blades  8  and  10  may comprise flexible synthetic rubber preventing bodily injury upon physical contact. 
     While the principles of the invention have been made clear in the above illustrative embodiment, those skilled in the art may make modifications in the structure, arrangement, portions and components of the invention without departing from those principles. Accordingly, it is intended that the description and drawings be interpreted as illustrative and not in the limiting sense, and that the invention be given a scope commensurate with the appended claims.