This invention broadly relates to rotary weed cutters and grass trimmers. More particularly my invention relates to rotary weed cutters that feed filaments out from rotating drive shafts to cut or trim weeds. Art pertinent to the present invention is classified in U.S. Class 30, subclass 276.
As will be appreciated by those skilled in the art, rotary weed cutters and grass trimmers employing flails have been present in the art for some time. The flails are made of various types of filaments, plastic or metal. Versatility of such devices over conventional lawn mowers or other grass cutting equipment is readily obvious. An operator may cut extremely close to structures or shrubbery or plants without a housing interfering with the ability to trim closely. Another advantage of course is the relative safety of the device. While it is not advisable for one to come into contact with the flails of such a weed cutter, it is surly not as dangerous as the solid blade of a conventional lawn mower.
Along with the aforementioned advantages some disadvantages are present in prior art weed cutters. Most weed cutters employ a housing or some other structure mounting a motor whether electric or internal combustion. A shaft extends from the motor through the housing to mount a spool or similar body to which the flails are attached or extend from. Weeds or vines often become wrapped around the shaft or housing. As these weeds or vines build up and tangle they eventually cause a drag on the motor. As a result the device slows to a speed where it will no longer cut, or it locks-up entirely. Such a lock-up is not only inconvenient but may also damage an electric motor or clutches associated with internal combustion engines. Several means have been proposed to eliminate such jamming.
Weed cutting devices employing flails are disclosed in numerous U.S. Pat. Nos. including 3,708,967; 3,826,068; 3,859,776 and 4,136,446.
U.S. Pat. No. 4,145,809, issued to Prouix discloses a weed cutting device with a rotary spool from which plastic wire outwardly projects. It provides a plurality of radially spaced apart rigid ramps which violently contact the weeds to prevent entanglement with the spool or shaft.
As disclosed in U.S. Pat. No. 4,223,441 issued Sep. 23, 1980, to Robert G. Everts it is known in the art to employ wire as well as plastic line as a flail.
An active, anti-jamming system for rotary weed cutters appears to be unknown. Hence, it is desirous to provide a weed cutter with the capacity to actively prevent weeds or vines, whether cut or uncut, from wrapping around the shaft during cutting. Not only will such an improvement speed the process of trimming or cutting weeds, it will also prevent damage to the drive motors and other systems related to the operation of the weed cutter.