Drawing lead sharpener

Claim 2

A sharpener for drawing leads, comprising a housing having top and side walls, an opening provided in said top wall, a collector member fastened to the underside of said top wall under the opening to enclose a suitable space to collect particles produced by the sharpening process, a driving means mounted on the underside of said collector member with the upper end of its shaft extending into the space enclosed by said collector member, a supporting member mounted on the upper end of said shaft, a cutter head having multiple removable cutting blades swivelly mounted on said supporting member in such a manner that said drawing lead, when inserted, can not contact said support member, said cutter head extending through the opening provided in the top wall of said housing and drivingly but removably connected to said supporting member, cutter head restraining means mounted in the opening in said top wall and cooperating with said cutter head to limit the swivelling motion of said cutter head, and switch means to automatically start said driving means when said drawing lead is inserted.

Claim 3

A sharpener for drawing leads, comprising a housing having top and side walls, an opening provided in said top wall, a collector member fastened to the underside of said top wall under the opening to enclose a suitable space to collect particles produced by the sharpening process, a driving means mounted on the underside of said collector member with the upper end of its shaft extending into the space enclosed by said collector member, a supporting member mounted on the upper end of said shaft and having at least one slot therein, a cutter head swivelly mounted on said supporting member and extending through the opening provided in the top wall and drivingly but removably connected thereto, cutter head restraining means mounted in the opening in said top wall and cooperating with said cutter head to limit the swivelling motion of said cutter head, and switch means to automatically start driving means when said drawing lead is inserted, wherein said cutter head includes an upper portion comprising a hollow cylinder having a tapered inner surface and being closed at the top thereof, and provided with an opening in the top to receive a drawing lead, a cutting cartridge adapted to receive multiple radially and axially extending blades, such that the inner cutting edges of said blades form the desired point on the lead, and the outer edges contact the tapered inner wall of said upper part and are securely retained in the cutting cartridge when inserted therein, multiple cutter blades inserted in said cutting cartridge, and a lower portion adapted to close the open end of said upper portion, thereby retaining said cutter cartridge, said lower portion having a bore therethrough to provide a discharge for the graphite particles produced by the cutter blades, said bore also being complimentary in shape to said supporting member to swivelly support said cutter head thereon, and a pin inserted in said bore to drivingly engage the slot in said supporting member to drive said cutter.

Claim 4

A sharpener for drawing leads, comprising a housing having top and side walls, an opening provided in said top wall, a collector member fastened to the underside of said top wall under the opening to enclose a suitable space to collect particles produced by the sharpening process, a driving means mounted on the underside of said collector member with the upper end of its shaft extending into the space enclosed by said collector member, a supporting member mounted on the upper end of said shaft and having at least one slot therein, a cutter head swivelly mounted on said supporting member and extending through the opening provided in the top wall and drivingly but removably connected thereto, cutter head restraining means mounted in the opening in said top wall and cooperating with said cutter head to limit the swivelling motion of said cutter head, and switch means to automatically start driving means when said drawing lead is inserted, wherein said cutter head includes an upper portion comprising a hollow cylinder having a tapered inner surface and being closed at the top thereof, and provided with an opening in the top to receive a drawing lead, a cutting cartridge adapted to receive multiple radially and axially extending blades, such that the inner cutting edges of said blades form the desired point on the lead, and the outer edges contact the tapered inner wall of said upper part and are securely retained in the cutting cartridge when inserted therein, multiple cutter blades inserted in said cutting cartridge, and a lower portion adapted to close the open end of said upper portion, thereby retaining said cutter cartridge, said lower portion having a bore therethrough to provide a discharge for the graphite particles produced by the cutter blades, said bore also being complimentary in shape to said supporting member to swivelly support said cutter head thereon, and a pin inserted in said bore to drivingly engage the slot in said supporting member to drive said cutter.

Claim 5

The device defined in claim 2, wherein said supporting member has an upper hemispherical shape portion and a lower cylindrically shaped mounting portion, said upper portion having at least one radially and axially eXtending slot provided therein.

Claim 6

The device defined in claim 2, wherein said supporting member has an upper hemispherical shaped portion and a lower cylindrical shaped mounting portion, said upper portion having two perpendicular radially and axially extending slots therein.

Claim 7

The device defined in claim 2, wherein the upper portion of said cutting head is provided with multiple axially extending slots in the side wall thereof for discharge of the graphite particles produced during the sharpening process.

Claim 8

The device defined in claim 3, and including a ball and spring retaining device adapted to engage the lower portion of the hemispherical part of the supporting member to prevent said cutting head from falling off, should the sharpener be upset in use.

Claim 9

The device defined in claim 2, wherein said housing has a circular cross-section.

Claim 10

The device defined in claim 2, wherein said drive means are in the form of an electric motor.

Claim 11

The device defined in claim 8, wherein said switch means are in the form of a spring contact, communicating with and driven by the movement of the motor shaft into and out of electrical contact with a rigid contact.