String trimmer head with curved trimmer line guide

Abstract

A trimmer head assembly for a trimming machine. The trimmer head assembly includes a spool. The spool has a central tubular hub. The spool also has a central flange that radially extends from the hub. A trim line conduit is joined to the central flange. The trim line conduit has a first open end. The first open end leads to a first straight section. The first straight section leads to a curved central section. The curved central section leads to a second straight section. The second straight section leads to a second open end. The curved central section passes around the center of the spool. A housing is provided that receives the spool therein. When loading trimmer line into the trimmer head assembly, the shape of the conduit enables the trimmer line to pass around the central opening in the spool without binding.

1 . A trimmer head assembly for a trimming machine, said trimmer head assembly comprising:
 a spool having a hub;   a top flange that radially extends from said hub;   a bottom flange that radially extends from said hub, and   a central flange that radially extends from said hub, wherein said hub is hollow and defines a central opening that extends through said hub;   a trim line conduit provided in said central flange, said trim line conduit having a first open end that leads to a first straight section, that leads to a curved central section, that leads to a second straight section, that leads to a second open end, wherein said curved central section passes around said central opening without passing into said central opening;   a housing that receives said spool therein, wherein eyelets are formed in said housing on opposite sides; and   an end cap that connects with said housing and retains said spool within said housing.   
     
     
         2 . The assembly according to  claim 1 , wherein said first straight section and said second straight section are linearly aligned on opposite sides of said curved central section. 
     
     
         3 . The assembly according to  claim 2 , wherein said first straight section of said conduit and said second straight section of said conduit are positioned a predetermined distance apart, wherein said first straight section and said second straight section have a combined length that is at least as long as said predetermined distance. 
     
     
         4 . The assembly according to  claim 1 , wherein said curved central section contains curves having a certain radii of curvature, and wherein said central opening has a circular cross-sectional profile with a predetermined radius of curvature, wherein each of said radii of curvature is greater than said predetermined radius of curvature. 
     
     
         5 . The assembly according to  claim 2 , wherein said first straight section and said second straight section are enclosed conduits. 
     
     
         6 . The assembly according to  claim 5 , wherein said curved central section includes an open relief formed around said central opening, wherein said relief has a curved peripheral wall, and wherein at least one deflector is disposed proximate said central opening within said relief, wherein said deflector and said curved peripheral wall create a curved channel that extends from said first straight section to said second straight section. 
     
     
         7 . The assembly according to  claim 1 , further comprising a knob that is coupled to said spool, wherein said knob extends through said end cap, therein enabling said spool to be manually rotated. 
     
     
         8 . The assembly according to  claim 1 , wherein the trim line conduit further comprises a second curved central section; wherein the first straight section leads to both the curved central section and the second curved central section; and wherein both the curved central section and the second curved central section lead to the second straight section; and wherein the second curved central section passes around said central opening without passing into said central opening. 
     
     
         9 . The assembly according to  claim 8 , wherein the second curved central section is a mirror image of the curved central section. 
     
     
         10 . The assembly according to  claim 8 , wherein the central opening is located between the curved central section and the second curved central section. 
     
     
         11 . The assembly according to  claim 8 , wherein the trim line conduit is enclosed between the first open end and the second open end. 
     
     
         12 . The assembly according to  claim 8 , wherein the trim line conduit is only partially enclosed between the first open end and the second open end. 
     
     
         13 . A spool for a trimmer head assembly, comprising:
 a hollow hub that defines a central opening that extends through said hub;   a flange radially extending from said hub;   a trim line conduit joined to said flange, said trim line conduit having a first open end that leads to a first straight section, that leads to a curved central section, that leads to a second straight section, that leads to a second open end, wherein said curved central section passes around said central opening without passing into said central opening, wherein said first straight section and said second straight section are linearly aligned on opposite sides of said curved central section, and wherein said first straight section of said conduit and said second straight section of said conduit are positioned a predetermined distance apart, wherein said first straight section and said second straight section have a combined length than is at least as long as said predetermined distance.   
     
     
         14 . The spool according to  claim 13 , wherein said curved central section contains curves having a certain radii of curvature, and wherein said central opening has a circular cross-sectional profile with a predetermined radius of curvature, wherein each of said radii of curvature is greater than said predetermined radius of curvature. 
     
     
         15 . The spool according to  claim 13 , wherein said first straight section and said second straight section are enclosed conduits. 
     
     
         16 . The spool according to  claim 13 , wherein the trim line conduit further comprises a second curved central section; wherein the first straight section leads to both the curved central section and the second curved central section; and wherein both the curved central section and the second curved central section lead to the second straight section; and wherein the second curved central section passes around said central opening without passing into said central opening. 
     
     
         17 . The spool according to  claim 13 , wherein said curved central section includes an open relief formed around said central opening, wherein said relief has a curved peripheral wall, and wherein at least one deflector is disposed proximate said central opening within said relief, wherein said deflector and said curved peripheral wall create a curved channel that extends from said first straight section to said second straight section. 
     
     
         18 . A trimmer head assembly for a trimming machine, said trimmer head assembly comprising:
 a spool having a hub and a flange radially extending therefrom, wherein said hub is hollow and defines a central opening that extends through said hub;   a trim line conduit joined to said flange, said trim line conduit having a first open end that leads to a first straight section, that leads to a central relief, that leads to a second straight section, that leads to a second open end, wherein said central relief has a curved peripheral wall;   at least one deflector disposed in said relief, wherein said at least one deflector and said curved peripheral wall define a guide channel that leads from said first straight section to said second straight section around said central opening.   
     
     
         19 . The assembly according to  claim 18 , wherein said first straight section and said second straight section are linearly aligned on opposite sides of said central relief. 
     
     
         20 . The assembly according to  claim 18 , wherein said first straight section of said conduit and said second straight section of said conduit are positioned a predetermined distance apart, wherein said first straight section and said second straight section have a combined length that is at least as long as said predetermined distance. 
     
     
         21 . The assembly according to  claim 18 , wherein said first straight section and said second straight section are enclosed conduits. 
     
     
         22 . The assembly according to  claim 18 , wherein said flange is the center flange of three parallel flanges that radially extend from said hub.