The Pencil Sharpener: A Blade Carried Round on a Planet Gear

Love's block or casing 5 has a circular chamber 6 whose wall has "an inwardly-directed flange or rim 8, which is provided with gear-teeth 9." A raised part 11 in the centre of the floor carries a pivoted arm 12, in one end of which is a sharpener 13. "The pencil-sharpener 13 is cylindrical in form, and the interior thereof is substantially of the usual construction": a conical opening with a cutting blade 14 in one side. A reduced extension 15 with a small central bore 16 passes through the arm, and the sharpener carries a pinion 19 meshing with the teeth 9. To use it, the pencil point is pushed in with slight pressure "and the said sharpener is carried around with the pivoted arm 12"; the sharpener "is rapidly revolved by means of the pinion" and the teeth. The bore lets "the finely-divided portions of the point of the pencil" drop into the chamber, and the sharpener can be lifted out and the box inverted to empty it.

Take the cutter body and blade out of a cheap hand pencil sharpener. Print a round box with an internal ring gear and a centre pivot, an arm, and a pinion that fits round the sharpener body (48 and 12 teeth work). Push-fit the sharpener into the pinion so it turns in the arm. Sharpen one pencil by carrying it round the box, counting trips, and another in the hand sharpener, counting turns. Measure the finished point angle and length with the caliper and compare how much each wasted. Keep the pencil upright and let it rotate only with the arm; if you twist it, you add or subtract turns.

**John Lee Love** of Fall River, Massachusetts, filed on 23 April 1897; US 594,114 is dated 23 November 1897. His claims are for the toothed chamber, the pivoted arm and a sharpener carried in it with a pinion. **Honest limits.** The tooth counts, cone angle and feed in the notebook are examples; the patent gives none of them.