Abstract: An assembly for use in continuously forming a plurality of lengths of flexible noise attenuating cutting line for use in rotary vegetation trimmers. The assembly includes a breaker plate having a conically shaped inner portion and a planar outer portion. A plurality of extrusion dies are disposed in the outer portion wherein each die defines a die hold configuration at its lower end for the extrusion of one or more monofilament polymer strands therethrough, and a drive assembly is provided for rotating each of the dies at a predetermined speed such that upon directing a flow of molten monofilament polymer material onto the breaker plate, the material is directed from the inclined central portion onto the planar outer portion where it is extruded through the rotating dies to create a plurality of twisted strands of polymer material that upon cooling, stretching and heating, define lengths of flexible noise attenuating cutting line.

Abstract: A cutting head for rotary trimmers in which at least one, and preferably two relatively short fixed lengths of flexible cutting line are inserted into opposed channels in the head and are secured in place by a pair of spring biased toothed cams. Each of the cams is pivotally mounted on a post within the housing adjacent one of the channels and defines a curvilinear camming surface having a plurality of uniformly spaced teeth thereon that project into the channels at increasing angles of inclination from the outermost tooth to the innermost tooth for engaging the line. A pair of torsion springs bias the cams to pivot on their mounting teeth such that the backsides of the teeth are continually urged toward the openings to the channels thereby allowing line to be inserted inwardly into the head past the toothed cams but retained by the cams against any outwardly directed forces acting on the line.

Abstract: A flexible noise attenuating cutting line for use in rotary vegetation trimmers formed by extruding a pair of molten monofilament strands in proximate disposition through a rotating die so as to form a line comprised of two monofilament polymer strands bonded together in a twisted disposition about a central longitudinal axis so as to define a pair of substantially V-shaped opposed troughs extending helically along and about the line.

Abstract: An improved flexible line rotary trimmer head of the type adapted to be bumped against the ground to effect payout of predetermined lengths of cutting line and which is secured to the trimmer by a drive bolt having a non-circular head portion and a depending shaft portion. The trimmer head housing defines a tubular portion depending axially from the upper housing surface and having a particularly configured upper portion disposed about and creating an interference fit with the head portion of said drive bolt and a lower portion particularly configured to create an interference fit with the head portion of the cam member of the line feeding assembly. A slidable push retainer is carried by the shaft portion of the drive bolt adjacent the line feeding assembly for securing the assembly to the shaft portion of the drive bolt.

Abstract: A flexible noise attenuating cutting line for use in rotary vegetation trimmers formed by extruding a pair of molten monofilament strands in proximate disposition through a rotating die so as to form a line comprised of two monofilament polymer strands bonded together in a twisted disposition about a central longitudinal axis so as to define a pair of substantially V-shaped opposed troughs extending helically along and about the line.

Abstract: A cutting head for rotary trimmers in which two relatively short fixed lengths of flexible cutting line are inserted into opposed channels in the head and are secured in place by a pair of spring biased toothed cams. Each of the cams is pivotally mounted on a post within the housing adjacent one of the channels and defines a curvilinear camming surface having a plurality of uniformly spaced teeth thereon that project into the channels at increasing angles of inclination from the outermost tooth to the innermost tooth for engaging the line. A pair of torsion springs bias the cams to pivot on their mounting teeth such that the backsides of the teeth are continually urged toward the openings to the channels thereby allowing line to be inserted inwardly into the head past the toothed cams but retained by the cams against any outwardly directed forces acting on the line. The cams are symmetrically balanced about their axes of rotation so as to be unaffected by centrifugal force acting thereon during use.

Abstract: A process for forming flexible cutting line for use in rotary vegetation trimmers of the type having two or more monofilament lines mounted on a common spool. The line produced by the process of the present invention defines two monofilament strands joined together in a side-by-side relationship by a severable bond. Each strand defines a plurality of circumferentially spaced and outwardly projecting vegetation cutting edges thereon, two of the edges on one of the strands being in parallel contact with two of the edges on the other strand so as to define a pair of parallel readily severable welds bonding the strands together in a side-by-side disposition.

Abstract: A process for forming flexible cutting line for use in rotary vegetation trimmers of the type having two or more monofilament lines mounted on a common spool. The line produced by the process of the present invention defines two monofilament strands joined together in a side-by-side relationship by a severable bond. Each strand defines a plurality of circumferentially spaced and outwardly projecting vegetation cutting edges thereon, two of the edges on one of the strands being in parallel contact with two of the edges on the other strand so as to define a pair of parallel readily severable welds bonding the strands together in a side-by-side disposition.

Abstract: A process for forming flexible cutting line for use in rotary vegetation trimmers of the type having two or more monofilament lines mounted on a common spool. The line produced by the process of the present invention defines two monofilament strands joined together in a side by side relationship by a severable bond. The process includes the steps of extruding one or more pairs of molten monofilament strands in proximate disposition, directing the strands together in a cooling quench bath, pulling the strands in an adjacent abutting disposition through the quench bath to initiate the crystallization and bonding together of the two strands, concurrently stretching and heating the bonded strands to effect parallel alignment of the molecular chain in the strands, heating the strands in a relaxed disposition, wetting the strands and spooling the wetted strands for storage and transportation.

Abstract: An assembly and process for continuously forming flexible cutting line for use in rotary vegetation trimmers of the type having two or more monofilament lines mounted on a common spool. The line produced by the present invention defines two monofilament strands joined together in a side by side relationship by a severable bond. The process includes the step of extruding one or more pairs of molten filament strands in proximate disposition through an extrusion die, directing the strands together about a collecting guide adjustably mounted in a cooling quench bath to initiate the forming of a severable weld between the adjacent strands. The elevation of the collecting guide within the quench tank is adjustable to vary the strength of the formed weld. The joined strands are then pulled in a parallel array through the quench bath and about a plurality of guide members therein to effect the crystallization and bonding together of the pairs of strands.