Weed and grass trimmer

Abstract

A weed and grass trimmer has a cutting line which is fed as the weed trimmer is in use. The weed trimmer's cutting head includes a spool for cutting line, and a housing. The spool has flanges around its circumference, which may engage a corresponding upper or lower set of flanges in the housing. Actuation of a control located near the handle operates either a cable or a solenoid, causing the spool to reciprocate between the upper and lower flanges. The difference in centrifugal force and angular velocity during this reciprocation causes additional cutting line to be fed.

1 . A line feed mechanism for a weed and grass trimmer, the weed and grass trimmer having a boom, a handle at one end of the boom, a cutting head at the opposite end of the boom, a motor, and a drive shaft connected between the motor and cutting head, said line feed mechanism comprising:
 a spool holding at least one cutting line, said spool having a top, a top plate, and sides, said top plate having circumferential flanges;   a housing covering said top and sides of said spool, said housing having one upper set of flanges and one lower set of flanges, each of said upper and lower set of flanges corresponding to said spool's flanges, said housing having at least one hole for receiving said cutting line, said housing further having a top and a bottom;   a spring fitting between said housing and said spool; and   means for causing said spool's flanges to selectively engage said upper flanges and said lower flanges of said housing.   
   
   
       2 - 3 . (canceled) 
   
   
       4 . The line feed mechanism according to  claim 1 , wherein said means for causing said spool's flanges to selectively engage said upper flanges and said lower flanges of said housing further include:
 an internal shaft slidably disposed within said driveshaft, said internal shaft comprising an upper portion and a lower portion, said upper portion having a threaded top, an internally threaded hexagonal portion mating with said housing, said internal thread mating with an external thread on said driveshaft, and a hollow portion, said lower portion being dimensioned and configured to fit within said hollow portion, said hollow portion defining a slot, said lower portion including a pin dimensioned and configured to reciprocate within said slot, said internal shaft passing through said housing and said spool, said lower portion further having an internally threaded end;   a cap having a threaded rod mating with said internal threads of said internal shaft;   a bearing secured to said threaded top of said internal shaft; and   a lever having a horizontal portion and a vertical portion, said horizontal portion, said bearing resting on top of said horizontal portion, said cable attaching to said vertical portion.   
   
   
       5 . The line feed mechanism according to  claim 1 , wherein said means for causing said spool's flanges to selectively engage said upper flanges and said lower flanges of said housing includes a solenoid. 
   
   
       6 - 8 . (canceled) 
   
   
       9 . A line feeder for a weed and grass trimmer, comprising:
 a) a spool for holding a cutting line, the spool having a circular top plate with a plurality of top plate flanges projecting radially from the circumference of the plate spaced apart at a predetermined angle;   b) a spool housing enclosing said spool, the spool housing being dome-shaped and having an open bottom and at least one hole defined therein for dispensing the cutting line;   c) a plurality of upper flanges disposed inside said spool housing, the upper flanges being equal in number to the flanges projecting from said top plate and spaced apart at the same predetermined angle as said top plate flanges;   d) a plurality of lower flanges disposed inside said spool housing in a horizontal plane below said upper flanges, the upper flanges being equal in number to the flanges projecting from said top plate and spaced apart at the same predetermined angle as said top plate flanges, said lower flanges being rotated by an angle of about one-half the predetermined angle separating said upper flanges so that each lower flange is positioned about midway between two of said upper flanges;   e) a bias spring positioned between the top plate of said spool and said spool housing, the spring normally biasing the top plate flanges of said spool into abutting contact with the lower flanges in said spool housing; and   f) line feeder means for causing relative movement between the top plate flanges and the lower and upper flanges of said spool housing in order to dispense increments of cutting line from said spool, said means being operable from a handle of a weed and grass trimmer without bumping the trimmer on the ground.   
   
   
       10 . (canceled) 
   
   
       11 . The line feeder according to  claim 9 , wherein said line feeder means moves said spool relative to said housing. 
   
   
       12 . (canceled) 
   
   
       13 . The line feeder according to  claim 9 , wherein said line feeder means comprises:
 a) a normally open electrical switch attachable to a handle of the weed and grass trimmer;   b) a bearing attached to said spool housing;   c) a solenoid having a plunger abutting said bearing, the solenoid being electrically connected to said switch;   d) wherein said spool is attachable to a driveshaft of the trimmer so that the spool is rotatable with the driveshaft;   e) wherein the top plate flanges are in abutting contact with said lower flanges when said electrical switch is in an open position;   f) wherein said electrical switch has a closed position in which the plunger of said solenoid moves to an extended position, pushing said bearing and said spool housing downward until the top plate flanges engage said upper flanges in order to dispense a first increment of cutting line; and   g) said bias spring raises said spool housing when said electrical switch is returned to the open position until the top plate flanges engage said lower flanges in order to dispense a second increment of cutting line.   
   
   
       14 . The line feeder according to  claim 9 , wherein said line feeder means comprises:
 a) a hand lever attachable to the handle of the weed and grass trimmer;   b) a cable having a first end attached to said hand lever and having a second end;   c) an internal shaft slidably insertable in a hollow driveshaft and having an upper end and a lower end;   d) a bearing disposed about the upper end of said internal shaft;   e) a pivotally mounted bearing lever having a first arm attached to the second end of said cable and a second arm in abutting contact with said bearing;   f) wherein said spool housing is connectable to the hollow driveshaft in order to rotate with the driveshaft;   g) wherein said spool is attached to the lower end of said internal shaft; and   h) wherein the second arm of said lever raises said bearing when said hand lever is pressed, whereby said spool is raised until the top plate flanges engage the upper flanges in said housing in order to dispense a first increment of cutting line; and   g) wherein said bias spring lowers said spool until the top plate flanges engage said lower flanges when said hand lever is released in order to dispense a second increment of cutting line.   
   
   
       15 . The line feeder according to  claim 9 , wherein said line feeder means comprises:
 a) a normally open electrical switch attachable to a handle of the weed and grass trimmer;   b) an internal shaft slidably insertable in a hollow driveshaft and having an upper end and a lower end;   c) a bearing disposed about the upper end of said internal shaft;   d) a pivotally mounted bearing lever having a first arm and a second arm in abutting contact with said bearing;   e) a solenoid having a plunger attached to the first arm of said bearing lever, the solenoid being electrically connected to said switch and the plunger being normally extended;   f) wherein said spool housing is connectable to the hollow driveshaft in order to rotate with the driveshaft;   g) wherein said spool is attached to the lower end of said internal shaft; and   h) wherein the second arm of said lever raises said bearing when said electrically switch is closed, the plunger being retracted, whereby said spool is raised until the top plate flanges engage the upper flanges in said housing in order to dispense a first increment of cutting line; and   g) wherein said bias spring lowers said spool until the top plate flanges engage said lower flanges when said electrical switch is returned to an open position in order to dispense a second increment of cutting line.   
   
   
       16 . The line feeder according to  claim 9 , wherein said spool has a unitary, one-piece construction. 
   
   
       17 . The line feeder according to  claim 9 , wherein said spool comprises:
 a) a circular top plate with a plurality of top plate flanges projecting radially from the circumference of the plate spaced apart at a predetermined angle;   b) a replaceable bobbin for holding at least one wound coil of cutting line;   c) a circular bottom plate, said bobbin being disposed between said top plate and said bottom plate; and   d) means for interlocking said top plate with said bobbin so that said bobbin rotates with said top plate.   
   
   
       18 . The line feeder according to  claim 17 , wherein said bottom plate is threadably attached to said top plate. 
   
   
       19 . The line feeder according to  claim 17 , wherein:
 a) said top plate further comprises a bolt extending from the plate for attachment to a driveshaft, and a cylindrical barrel depending from the plate, the barrel having a bottom face with a cylindrical cavity defined therein, the cavity having an annular groove defined therein;   b) the bottom plate further comprises a knob depending therefrom and a cylindrical button housing extending through the knob and above a top face of the bottom plate, the button housing having a plurality of holes defined therein; and   
     wherein said line feeder further comprises:
 c) a cylindrical button slidably disposed in the button housing, the button having a head and having an annular groove defined about its circumference; 
 d) a bias spring disposed between said button and the button housing, the spring biasing the button head below said knob; and 
 e) a plurality of detent balls disposed between said button and said button housing, said balls partially extending through said holes and lodging in the annular groove defined in the cavity defined in the barrel of said top plate to secure the bottom plate to the top plate when said button is biased downward, and said balls partly retracting into the annular groove defined in said button so that said balls do not extend through said holes when said button is pushed against said bias spring in order to permit said bottom plate and said top plate to separate for removal of said bobbin. 
 
   
   
       20 . (canceled)