US Patent 7900429 Liquid herbicide applicator drive shaft rotary seal

An apparatus and method for supply of treating fluid to a cutting apparatus directly to cut vegetation substantially simultaneously with the cutting of the vegetation. Treating fluid is delivered from the supply to an intermediate, sealed reservoir into which a desired volume of treating fluid is maintained and a rotary shaft seal is provided to seal the reservoir against entrance of debris. The treating fluid is then delivered from the sealed reservoir, via centrifugal force, through a channel to a passageway formed in the bolt connecting the cutting blade to a blade mount of the mower.