# US 8,769,831 B2 · Combination string and blade trimmer head > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,769,831 B2 - Document ID: US8769831B2 - Status: Granted - Kind: B2 - Application number: 13/446,348 - Filed: 2012-04-13 - Published: 2012-10-18 - Granted: 2014-07-08 - Earliest claimed: 2011-04-13 - Applicants: Randy A. Duvall - Inventors: Randy A. Duvall - Web page: https://patentgrep.com/patent/US8769831B2 ## CPC - A01D 34/4166: {Mounting or replacement of the lines} - A01D 34/733: {Cutting-blade mounting means} - A01D 34/736: {Flail type} - A01D: HARVESTING; MOWING ## Abstract A trimmer head for cutting vegetation is adaptable to operate in blade trimming mode and in monofilament trimming mode, and requires minimal time and effort to change between the two modes. The device comprises a bottom plate and a top plate. The top and bottom plate are urged together, thereby locking the blades in place. When the top and bottom plate are separated and rotated relative to one another, a blade may be inserted or removed from the blade posts by a gap formed between the top of the blade post and the top plate. The top plate includes a surface having a plurality of trimmer blade posts adaptable to pivotally mount at least one trimmer blade. The top plate further comprises a plurality of monofilament holes for receiving a monofilament line therethrough. ## Claims ### Claim 1 A device for cutting vegetation having a first and second configuration, the device comprising: a bottom plate comprising a plurality of first level sections, a plurality of second level sections, a plurality of recessed sections, and a plurality of first level holes located on the plurality of first level sections; a top plate removably attached to the bottom plate, the top plate including a bottom surface and a top surface; a retaining and rotation component allowing the bottom plate and top plate to rotate relative to one another and which urges the bottom plate against the top plate; wherein the bottom surface comprises a plurality of recessed portions, a bottom surface hole located at the center of the bottom surface, and a plurality of trimmer blade posts adaptable to pivotally mount at least one trimmer blade thereon to operate the device in a blade trimming mode; wherein the top surface comprises a trimmer attachment mount and a plurality of monofilament conduits adaptable to engage with at least one monofilament line; wherein in said first configuration the bottom plate engages with the top plate bottom surface such that the plurality of trimmer blade posts in the bottom surface connects with the plurality of first level holes located on the plurality of first level sections to firmly engage the at least one trimmer blade; and wherein in said second configuration said bottom plate is rotated relative to said top plate and disengaged from said top plate such that said at least one trimmer blade becomes disengaged from the at least one of the plurality of trimmer blade posts and the at least one of the plurality of first level sections. ### Claim 2 (depends on 1) The device of claim 1 wherein the retaining and rotation component comprises a shaft, a spring, a retaining pin and a pin hole receiving the retaining pin. ### Claim 3 (depends on 1) The device of claim 1 wherein the retaining and rotation component passes through the bottom surface hole. ### Claim 4 (depends on 1) The device of claim 1 wherein the plurality of monofilament conduits is arranged in pairs around the circumference of the top plate. ### Claim 5 (depends on 1) The device of claim 1 wherein at least one monofilament line is inserted through the plurality of monofilament conduits. ### Claim 6 (depends on 1) The device of claim 1 wherein in said first configuration the plurality of second level sections is engaged with the top plate bottom surface. ### Claim 7 (depends on 1) The device of claim 1 wherein the plurality of second level sections is positioned closer to the bottom surface than the plurality of first level sections. ### Claim 8 (depends on 1) The device of claim 1 wherein when the bottom plate is spaced away from and rotated relative to the top plate, a gap is formed between an end portion of the at least one of the plurality of trimmer blade posts and the at least one of the plurality of first level sections. ### Claim 9 A trimmer head having a first and second configuration, the trimmer head comprising: a bottom plate comprising a plurality of first level sections, a plurality of second level sections, a plurality of recessed sections, and a plurality of first level holes located on the plurality of first level sections; a top plate removably attached to the bottom plate, the top plate including a bottom surface and a top surface; a retaining and rotation component allowing the bottom plate and top plate to rotate relative to one another and which urges the bottom plate against the top plate; wherein the bottom surface comprises a plurality of bottom recessed portions, a bottom surface hole located at the center of the bottom surface, and a plurality of trimmer blade posts adaptable to pivotally mount at least one trimmer blade thereon to operate the trimmer head in a blade trimming mode; wherein the top surface comprises a trimmer attachment mount and a plurality of monofilament conduits adaptable to engage with at least one monofilament line; wherein in said first configuration the plurality of trimmer blade posts in the top plate bottom surface connects with the plurality of first level holes located on the plurality of first level sections to firmly engage the at least one trimmer blade; and wherein in said second configuration said bottom plate is rotated relative to said top plate and disengaged from said top plate such that the at least one trimmer blade becomes disengaged from the at least one of the plurality of trimmer blade posts and the at least one of the plurality of first level sections. ### Claim 10 (depends on 9) The trimmer head of claim 9 wherein the retaining and rotation component is passes through the bottom surface hole. ### Claim 11 (depends on 9) The trimmer head of claim 9 wherein the plurality of monofilament conduits is arranged in pairs around the circumference of the top plate. ### Claim 12 (depends on 9) The trimmer head of claim 9 wherein at least one monofilament line is inserted through the plurality of monofilament conduits. ### Claim 13 (depends on 9) The trimmer head of claim 9 wherein in said second configuration the plurality of second level sections disengages from the top plate bottom surface and a gap is formed through which at least one trimmer blade may pass. ### Claim 14 (depends on 9) The trimmer head of claim 9 wherein in said first configuration the plurality of second level sections is engaged with the top plate bottom surface. ### Claim 15 (depends on 9) The trimmer head of claim 9 wherein the plurality of second level sections is positioned closer to the bottom surface than the plurality of first level sections. ### Claim 16 A trimmer head adaptable to operate in two modes, comprising: a bottom plate comprising a plurality of first level sections, a plurality of second level sections, a plurality of recessed sections, and a plurality of first level holes located on the plurality of first level sections; a top plate removably attached to the bottom plate, the top plate including a bottom surface and a top surface; a retaining and rotation component allowing the bottom plate and top plate to rotate relative to one another and which urges the bottom plate against the top plate; wherein the bottom surface comprises a plurality of bottom recessed portions, a bottom surface hole located at the center of the bottom surface, and a plurality of trimmer blade posts adaptable to pivotally mount at least one trimmer blade thereon to operate the trimmer head in a blade trimming mode; wherein the top surface comprises a trimmer attachment mount and a plurality of monofilament conduits arranged in pairs around the circumference of the top surface adaptable to engage with at least one monofilament line; wherein in said first configuration the plurality of trimmer blade posts in the top plate bottom surface connects with the plurality of first level holes located on the plurality of first level sections to firmly engage the at least one trimmer blade; wherein in said second configuration said bottom plate is rotated relative to said top plate and disengaged from said top plate such that the at least one trimmer blade becomes disengaged from the at least one of the plurality of trimmer blade posts and the at least one of the plurality of first level sections. ### Claim 17 (depends on 16) The trimmer head of claim 16 wherein the retaining and rotation component is passes through the bottom surface hole. ### Claim 18 (depends on 16) The trimmer head of claim 16 the at least one monofilament line is inserted through the plurality of monofilament conduits. ### Claim 19 (depends on 16) The trimmer head of claim 16 wherein in said first configuration the plurality of second level sections is engaged with the top plate bottom surface. ### Claim 20 (depends on 16) The trimmer head of claim 16 wherein the plurality of second level sections is positioned closer to the bottom surface than the plurality of first level sections. ### Claim 21 (depends on 16) The trimmer head of claim 16 wherein when the bottom plate is spaced away from and rotated relative to the top plate, a gap is formed between the end portion of the at least one of the plurality of trimmer blade posts and the at least one of the plurality of first level sections. ### Claim 22 (depends on 16) The trimmer head of claim 16 wherein the plurality of monofilament conduits is arranged at about sixty degrees from the plurality of trimmer blade posts.