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US 3,991,798 AGranted
Disposable device for sharpening leads or the like
OwnerRobert M. Grosjeaninventor
Life of this patent
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OwnerRobert M. Grosjeaninventor
Estimating the term…
A device is provided for sharpening leads of pencils or the like. The sharpening device is disposable and is designed to be thrown away when filled, without the necessity for cleaning out the device which inherently results in a dirty mess and in a waste of time. The sharpening device employs a minimum number of parts so as to achieve low cost and dependability in operation. A main top unit and a main lower unit are rotatably connected together without any additional elements such as nuts or the like being required. The sharpener also includes a gasket which retains the powdered graphite from the lead in the lower unit and also wipes the lead being sharpened. The outer wall of the lower unit has a truncated conical abrasive surface to effect the sharpening, with this wall being somewhat flexible to avoid breakage of the lead being sharpened. The sharpener can be mounted in place on a drafting table or the like by an adhesive disc or by a separable mounting block which is reusable.
A device for sharpening points of leads or the like comprising a lower unit having an annular cavity opening upwardly and a central passage, means forming an abrasive surface adjacent said annular cavity, an upper unit having a central axle extending downwardly through said passage and having integral means at the lower end cooperating with integral means associated with said passage to enable said upper unit to rotate relative to said lower unit but to prevent said upper unit from being separated from said lower unit, said upper unit having means spaced from said axle and positioned over said abrasive surface means for receiving a lead.
A device for sharpening lead comprising a lower unit having an outer wall of circular cross section, an inner wall of circular cross section, and a bottom wall connecting said outer and inner walls to form an upwardly-facing annular cavity, said inner wall having an inwardly-extending web at the upper end thereof, central wall means forming a passage centrally located with respect to said lower unit and having an upper end connected with said web, said device further comprising an upper unit having a central axle extending into said passage, said passage and said axle having structurally-integral cooperating means to resist said axle from being moved outwardly from said passage, and said upper unit further having wall means forming a guide with an opening at the bottom thereof spaced from said axle and positioned above a portion of said annular cavity, and abrasive means on said outer wall forming an abrasive surface below said opening of said guide.
Dependencies are inferred from the claim text.