String trimmer head having invertible components that enable selective clockwise and counterclockwise operations
View Patent ↗A trimmer head assembly has a housing that defines an interior. A spool is provided. The spool can be inserted into the interior of the housing either in an upright configuration or in a flipped inverted orientation. A spring is provided in the housing that biases the spool into a first position within the housing. A ratcheting mechanism exists between the spool and the housing that enables the spool to rotate only in a first direction when in said first position. The direction of rotation permitted by the ratcheting mechanism depends upon the orientation of the spool within the housing. In this manner, a single trimmer head assembly can be made to operate on a clockwise trimmer or a counterclockwise trimmer merely by inverting the spool.
1. A trimmer head assembly that is rotated by a drive shaft of a trimmer machine, said trimmer head assembly comprising:
a housing cup having an open end wherein said housing cup is affixed to the drive shaft of the trimmer machine and is rotated by the drive shaft;
a housing cap having a first face surface and a second face surface that is selectively attachable to said housing cup over said open end in a forward orientation where said first face surface faces an interior space defined by said housing cup and said housing cap, and a reverse orientation where said second face surface faces said interior space, and wherein an opening is centrally formed through said housing cap; a spool for containing trimmer line and having stop projections that face the housing cap is disposed within said interior space;
a spring disposed within said interior that biases said spool downwardly into contact with said housing cap with a downward bias force;
a ratcheting mechanism that exists between said spool and said housing cap that enables said spool to rotate only in a first direction when said spool is biased into contact with said housing cap by said spring,
said ratcheting mechanism consisting of ramp projections disposed on both said first face surface of said housing cap and said second face surface of said housing cap that respectively contact said stop projections when said housing cap is attached to said housing cup in either the forward or reverse orientation, and wherein said ramp projections on said first face surface of said housing cap are oriented in a direction opposite those on said second face surface of said housing cap; and
a bump knob extending through said opening in said housing cap, wherein said bump knob is separate and distinct from said spool and contacts said spool to move said spool out of contact with said housing cap when bumped to create a upward force greater than said downward bias force provided by said spring.
2. The assembly according to claim 1 , wherein said ratcheting mechanism enables said spool to rotate within said housing only in a second direction that is opposite said first direction when said spool is inverted within said interior from said first orientation to said second orientation.
3. The assembly according to claim 1 , wherein said housing cup and said housing cap are selectively detachable.