# US 5,699,620 A · Apparatus for sharpening crayon marking instruments to form an improved arcuate safety marking tip > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,699,620 A - Document ID: US5699620A - Status: Granted - Kind: A - Application number: 08/766,536 - Filed: 1996-12-11 - Granted: 1997-12-23 - Earliest claimed: 1996-12-11 - Assignees: Pentech International Inc. - Inventors: Frederick B. Hadtke; Linda El-Fakir; Greg M. Rosen - Web page: https://patentgrep.com/patent/US5699620A ## CPC - B43L 23/08: in which the pencils or leads are sharpened mainly by rotational movement against cutting blades (B43L23/02 takes precedence) - B43L: ARTICLES FOR WRITING OR DRAWING UPON; {WRITING OR DRAWING AIDS;} ACCESSORIES FOR WRITING OR DRAWING (workshop equipment for marking-out work B25H7/00; teaching hand-writing or drawing G09B11/00) ## Abstract A device for sharpening crayons and other soft marking instruments normally made from waxes, plastics and other soft material which includes a protective ring defining an aperture with a plurality of support members extending longitudinally therefrom. A plurality of sharpening blades extend longitudinally along the support members and are fixedly secured thereto to define a sharpening zone between the support members. Each of the sharpening blades is arcuate along its entire length extending from the protective ring to a base to which the individual support members converge. This arcuate shape is preferably of a parabolic shape to facilitate the sharpening of crayons to a blunt end shape. Debris outlets are defined between the support members and a retaining cup can be secured thereto for collecting debris. The sharpening blades are formed by blade surfaces oriented at approximately 90 degrees with respect to one another and at approximately 45 degrees with respect to the crayon marking instrument being sharpened in order to maximize sharpening and minimize any danger of accidents such as cutting of one's fingers especially by young children. ## Claims ### Claim 1 An improved apparatus for safely sharpening crayon marking instruments made from waxes, plastics and similar soft materials, said apparatus comprising: A. a protective ring means defining an inlet aperture means oriented laterally therein and adapted to receive a crayon marking instrument extending therethrough to facilitate sharpening thereof, said protective ring means being greater than 0.5625 inches in diameter to facilitate sharpening of crayon marking instruments of difference sizes; B. an inlet flange means fixedly secured to said protective ring means and extending laterally outwardly therefrom to facilitate mounting of the sharpening apparatus; C. a plurality of support members fixedly secured to said protective ring means and extending outwardly longitudinally therefrom, said support members and said protective ring means defining a sharpening zone means therebetween adapted to receive a crayon marking instrument therein for sharpening thereof, each of said support members including a proximate end fixedly secured to said protective ring means and a distal end spatially disposed from said proximate end thereof, each adjacent pair of said support members cooperating together to define a debris outlet means therebetween for allowing exiting of materials removed from the crayon marking instrument during sharpening thereof; D. a base member positioned spatially disposed longitudinally from said protective ring means and fixedly secured to each of said distal ends of said support members; E. a plurality of main sharpening blades each of which being fixed secured to each of said support members and extending therealong, each of said main sharpening blades defining an arcuate cutting edge extending therealong and positioned adjacent said sharpening zone means to facilitate sharpening of a crayon marking instrument positioned therewithin, said arcuate cutting edges being arcuate along the entire length thereof and each of said arcuate cutting edges extending along the entire longitudinal length of its respective support member from said inlet aperture means completely to said base member, said arcuate cutting edge of each of said main sharpening blades including a main parabolic cutting profile extending longitudinally therealong, said main sharpening blades being oriented at approximately 45 degrees with respect to a crayon marking instrument being sharpened within said sharpening zone means, said support members with said main sharpening blades secured fixedly thereto extending longitudinally from said protective ring means in converging relation with respect to one another with the distal ends thereof positioned more closely with respect to one another than said proximate ends thereof, said main sharpening blades including: (1) a first blade surface; (2) a second blade surface intersecting with said first blade surface to form said arcuate cutting edge therebetween, said first blade surface and said second blade surface being oriented with respect to one another at an angle of approximately ninety degrees; F. a plurality of supplementary sharpening blades each being fixedly secured to said base member and extending longitudinally therefrom between each pair of adjacent main sharpening blades to facilitate sharpening of the endmost portion of a crayon marking instrument, each of said supplementary sharpening blades being secured to said base member equally spaced from each of said main sharpening blades positioned thereadjacent, each of said supplementary sharpening blades extending from said base member to an intermediate longitudinal position, each of said supplementary sharpening blades including a supplemental parabolic cutting profile extending longitudinally therealong; G. a mounting collar fixedly secured to said protective ring means and extending laterally outwardly therefrom in surrounding relation to said support members and said main sharpening blades to further facilitate mounting thereof; and H. a retaining cup means positioned in surrounding relationship to said support members and said base member and in engagement with respect to said inlet flange means to define a debris retaining chamber therewithin for receiving and retaining sharpening debris therein, said retaining cup means being detachably securable with respect to said inlet flange means to facilitate removal of sharpening debris from said debris retaining chamber defined therewithin. ### Claim 2 An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon, said apparatus comprising: A. a protective ring means defining an inlet aperture means oriented laterally therein and adapted to receive a crayon marking instrument extending therethrough to facilitate sharpening thereof; B. a plurality of support members fixedly secured to said protective ring means and extending outwardly longitudinally therefrom, said support members and said protective ring means defining a sharpening zone means therebetween adapted to receive a crayon marking instrument therein for sharpening thereof, each of said support members including a proximate end fixedly secured to said protective ring means and a distal end spatially disposed from said proximate end thereof; C. a base member positioned spatially disposed longitudinally from said protective ring means and fixedly secured to each of said distal ends of said support members; D. a plurality of main sharpening blades each of which being fixed secured to each of said support members and extending therealong, each of said main sharpening blades defining an arcuate cutting edge extending therealong and positioned adjacent said sharpening zone means to facilitate sharpening of a crayon marking instrument positioned therewithin, said arcuate cutting edges being arcuate along the entire length thereof and each of said arcuate cutting edges extending along the entire longitudinal length of said support members from said inlet aperture means completely to said base member, said arcuate cutting edge of each of said main sharpening blades including a main parabolic cutting profile extending longitudinally therealong, said main sharpening blades being oriented at approximately 45 degrees with respect to a crayon marking instrument being sharpened within said sharpening zone means, said main sharpening blades including: (1) a first blade surface; (2) a second blade surface intersecting with said first blade surface to form said arcuate cutting edge therebetween, said first blade surface and said second blade surface being oriented with respect to one another at an angle of approximately sixty to ninety degrees; and E. a plurality of supplementary sharpening blades each being fixedly secured to said base member and extending longitudinally therefrom between each pair of adjacent main sharpening blades to facilitate sharpening of the endmost portion of a crayon marking instrument. ### Claim 3 An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon, said apparatus comprising: A. a protective ring means defining an inlet aperture means oriented laterally therein and adapted to receive a crayon marking instrument extending therethrough to facilitate sharpening thereof; B. a plurality of support members fixedly secured to said protective ring means and extending outwardly longitudinally therefrom, said support members and said protective ring means defining a sharpening zone means therebetween adapted to receive a crayon marking instrument therein for sharpening thereof, each of said support members including a proximate end fixedly secured to said protective ring means and a distal end spatially disposed from said proximate end thereof; C. a base member positioned spatially disposed longitudinally from said protective ring means and fixedly secured to each of said distal ends of said support members; and D. a plurality of main sharpening blades each of which being fixed secured to each of said support members and extending therealong, each of said main sharpening blades defining an arcuate cutting edge extending therealong and positioned adjacent said sharpening zone means to facilitate sharpening of a crayon marking instrument positioned therewithin, said arcuate cutting edges being arcuate along the entire length thereof. ### Claim 4 (depends on 1) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 1 wherein each of said arcuate cutting edges extends along the entire longitudinal length of its respective support member from said inlet aperture means completely to said base member. ### Claim 5 (depends on 1) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 1 wherein each adjacent pair of said support members cooperate together to define a debris outlet means therebetween for allowing exiting of materials removed from the crayon marking instrument during sharpening thereof. ### Claim 6 (depends on 1) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 1 wherein said arcuate cutting edge of each of said main sharpening blades includes a main parabolic cutting profile extending longitudinally therealong. ### Claim 7 (depends on 1) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 1 further comprising a plurality of supplementary sharpening blades fixedly secured to said base member and extending longitudinally therefrom between each pair of adjacent main sharpening blades to facilitate sharpening of the endmost portion of a crayon marking instrument. ### Claim 8 (depends on 7) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 7 wherein each of said supplementary sharpening blades are secured to said base member equally spaced from each of said main sharpening blades positioned thereadjacent. ### Claim 9 (depends on 7) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 7 wherein each of said supplementary sharpening blades extends from said base member to an intermediate longitudinal position. ### Claim 10 (depends on 7) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 7 wherein each of said supplementary sharpening blades includes a supplemental parabolic cutting profile extending longitudinally therealong. ### Claim 11 (depends on 1) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 1 further comprising a mounting collar fixedly secured to said protective ring means and extending laterally outwardly therefrom in surrounding relation to said support members and said main sharpening blades to further facilitate mounting thereof. ### Claim 12 (depends on 1) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 1 further comprising an inlet flange means fixedly secured to said protective ring means and extending laterally outwardly therefrom to facilitate mounting of the sharpening apparatus as desired. ### Claim 13 (depends on 12) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 12 further comprising a retaining cup means positioned in surrounding relationship to said support members and said base member and in engagement with respect to said inlet flange means to define a debris retaining chamber therewithin for receiving and retaining sharpening debris. ### Claim 14 (depends on 13) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 13 wherein said retaining cup means is detachably securable with respect to said inlet flange means to facilitate removal of sharpening debris from said debris retaining chamber defined therewithin. ### Claim 15 (depends on 12) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 12 wherein said inlet flange means includes a plurality of dimple means therein to facilitate grasping thereof during operation of the sharpening apparatus. ### Claim 16 (depends on 1) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 1 wherein said main sharpening blades are oriented at approximately 45 degrees with respect to a crayon marking instrument being sharpened within said sharpening zone means. ### Claim 17 (depends on 1) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 1 wherein said main sharpening blades include a first blade surface and a second blade surface which intersect to form said arcuate cutting edge therebetween. ### Claim 18 (depends on 17) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 17 wherein said first blade surface and said second blade surface are oriented with respect to one another at an angle of sixty to ninety degrees, inclusive. ### Claim 19 (depends on 17) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 17 wherein said first blade surface and said second blade surface are oriented with respect to one another at an angle of approximately ninety degrees. ### Claim 20 (depends on 3) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 3 wherein said support members and said main sharpening blades secured fixedly thereto extend longitudinally from said protective ring means in converging relation with respect to one another with the distal ends thereof positioned more closely with respect to one another than said proximate ends thereof. ### Claim 21 (depends on 3) An apparatus for sharpening crayon marking instruments made from waxes, plastics and other soft materials by forming an improved arcuate and blunted safety marking end thereon as defined in claim 3 wherein said protective ring means is greater than 0.5625 inches in diameter.