Rotary cutting assembly

Claim 2

Apparatus for cutting vegetation and the like comprising a rotary member rotatable in a cutting plane about an axis, a flexible non-metallic line means having a first secured portion interconnected with said rotary member and having a second free traveling end portion extending from a point on said rotary member spaced in said cutting plane from said axis, said line means having a cross sectional diameter substantially at least 0.025 inches and not substantially greater than 0.100 inches, and driving means for rotating said rotary member about said axis at a rotation velocity such that the tip velocity of said free traveling end portion of said line means is at least 5,600/3 cube root d feet per second, where d is the cross sectional diameter in inches of said line means.

Claim 3

The apparatus described in claim 1, wherein said line means also includes a second secured portion interconnected with said rotary member and a second free traveling end portion extending a second point on said rotary member spaced in said cutting plane from said axis.

Claim 4

Apparatus for cutting vegetation and the like, comprising a housing rotatable in a cutting plane and having at least one internal storage compartment and at least one wall aperture communicating therewith and defined by spaced-apart curvilinear side-wall surfaces aligned with the rotation axis of said housing, flexible non-metallic line means coiled within said compartment oppositely of the rotation of said housing and having a free-traveling end portion extending respectively through said wall aperture an unsupported distance functionally related to the cross sectional diameter of said line means, and driving means for revolving said housing and line means about said axis at a rotation velocity imparting a preselected tip energy to said line means, said rotation velocity further being substantially such that the tip velocity of said free traveling end portion of said line means is at least 5600/3 Cube Root d feet per second and not greater than 21,000/16 Cube Root d feet per second, where d is the cross sectional diameter in inches of said line member.

Claim 5

Apparatus for cutting vegetation and the like, comprising a housing rotatable in a cutting plane and having at least one internal storage compartment and at least one wall aperture communicating therewith and defined by spaced-apart curvilinear side-wall surfaces aligned with the rotation axis of said housing, flexible non-metallic line means coiled within said compartment oppositely of the rotation of said housing and having a free-traveling end portion extending respectively through said wall aperture an unsupported distance functionally related to the cross sectional diameter of said line means, and driving means for revolving said housing and line means about said axis at a rotation velocity imparting a preselected tip energy to said line means, said rotation velocity further being substantially such that the tip velocity of said free traveling end portion of said line means is at least 5600/3 Cube Root d feet per second and not greater than 21,000/16 Cube Root d feet per second, where d is the cross sectional diameter in inches of said line member.

Claim 6

The apparatus described in claim 3, wherein said free traveling end portion of said line means extends from said housing an unsupported distance greater than at least five inches and not substantially greater than nine inches in length.

Claim 7

The apparatus described in claim 4, wherein said line means has at least four separated free traveling end portions each extending from one of a corresponding plurality of locations equally spaced about the periphery of said housing and laterally in said cutting plane, and wherein said driving means is a gasoline-driven engine adapted to revolve said housing at a rotational velocity of not less than 2,500 revolutions per minute and not greater than 4,000 revolutions per minute during intersection of vegetation and the like by said four end portions of said line means.

Claim 8

The apparatus described in claim 5, wherein said housing comprises a rotary body fixedly attachable concentrically to the shaft of said engine and having four internal circular compartments spaced about said engine shaft and each communicating separately with one of four equally spaced apart window apertures each defined by curvilinear wall portions of the periphery of said body, said compartments in said rotary body also each communicating with one of four non-circular apertures equally spaced about said engine shaft and between said shaft and the periphery of said body, four separate spool-like members each removably disPosed in one of said circular compartments in said body and each having circular upper and lower flange portions rotatable in said compartments and a non circular knob-like portion protruding from said upper flange portion and insertable in the corresponding one of said non-circular apertures in said body, four separate non-metallic line members each having one end secured to and wound about one of said spool members and having its other end extending from the respective compartment through the corresponding one of said window apertures and radially outwardly of the periphery of said body, a cup member detachably fastened to said rotary body for forming with said body a rotatable housing assembly enclosing said spool members in said compartments, and four separate spring members mounted in said cup member and yieldably thrusting said non-circular knob-like portions of said spool members insertably into and through said non-circular apertures in said body.

Claim 9

The apparatus described in claim 4, wherein said line means has a pair of separated free traveling end portions each extending from one of a pair of equally spaced apart locations on opposite sides of the periphery of said housing and laterally in said cutting plane, and wherein said driving means is a non-synchronous electric motor adapted to revolve said housing at a rotational velocity of not less than 3,500 revolutions per minute and not greater than 7, 000 revolutions per minute during intersection of vegetation and the like by said pair of end portions of said line means.

Claim 10

The apparatus described in claim 7, wherein the cross sectional diameter of said line means is substantially 0.035 inches and said tip velocity is greater than 17,000 feet per minute but not greater than 26,000 feet per minute.

Claim 11

The apparatus described in claim 7, wherein the cross sectional diameter of said line means is substantially 0.065 inches and said tip velocity is greater than 14,000 feet per minute but not greater than 25,000 feet per minute.

Claim 12

The apparatus described in claim 7, wherein the cross sectional diameter of said line means is substantially 0.100 inches and said tip velocity is greater than 12,000 feet per minute but not greater than 23,000 feet per minute.

Claim 13

As a sub-assembly in apparatus for cutting vegetation and the like, means comprising a rotary housing rotatable about a concentric axis and having four internal circular compartments spaced about a concentric axis and each communicating separately with one of four equally spaced apart window apertures each defined by curvilinear wall portions of the periphery of said housing, said compartments in said rotary housing also each communicating with one of four non-circular apertures equally spaced about said axis and between said axis and the periphery of said housing, four separate spool-like members each removably disposed in one of said circular compartments in said housing and each having circular upper and lower flange portions rotatable in said compartments and a non circular knob-like portion protruding from said upper flange portion and insertable in the corresponding one of said non-circular apertures in said housing, four separate non-metallic line members each having one end secured to and wound about one of said spool members and having its other end extending from the respective compartment through the corresponding one of said window apertures and radially outwardly of the periphery of said housing, a cup member detachably fastened to said rotary housing for forming with said housing a rotatable housing assembly enclosing said spool members in said compartments, and four separate spring members mounted in said cup member and yieldably thrusting said non-circular knob-like portions of said spool members insertably into and through said non-circular apertures in said housing.

Claim 14

As a sub-assembly in apparatus for cutting vegetation and the like, means comprising a rotary housing rotatable about a concentric axis and having four internal circular compartments spaced about a concentric axis and each communicating separately with one of four equally spaced apart window apertures each defined by curvilinear wall portions of the periphery of said housing, said compartments in said rotary housing also each communicating with one of four non-circular apertures equally spaced about said axis and between said axis and the periphery of said housing, four separate spool-like members each removably disposed in one of said circular compartments in said housing and each having circular upper and lower flange portions rotatable in said compartments and a non circular knob-like portion protruding from said upper flange portion and insertable in the corresponding one of said non-circular apertures in said housing, four separate non-metallic line members each having one end secured to and wound about one of said spool members and having its other end extending from the respective compartment through the corresponding one of said window apertures and radially outwardly of the periphery of said housing, a cup member detachably fastened to said rotary housing for forming with said housing a rotatable housing assembly enclosing said spool members in said compartments, and four separate spring members mounted in said cup member and yieldably thrusting said non-circular knob-like portions of said spool members insertably into and through said non-circular apertures in said housing.