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US 7,651,289 B2Granted
Writing instrument
OwnerNehad Bahbahaniinventor
Life of this patent
Estimating the term…
Abstract
An adjustable pencil for varying the pressure on a piece of lead includes a cylindrical barrel, and a guide tube containing a piece of lead disposed in the barrel. A coil spring, a rectangular channel with a plurality of stops and a follower compresses the spring for increasing or decreasing the longitudinal force applied to the lead as it engages a writing surface. A knob rotates the guide tube to open or close a pair of jaw like grips for maintaining a pre-selected length of lead extending from the tip of the pencil.
Claims2
An adjustable pencil for varying the pressure on a piece of lead, said pencil comprising:
- an elongated cylindrical barrel having a longitudinal axis and a longitudinal passageway extending through said barrel and said barrel including a forward portion, a tip at a forward end of said forward portion and a rear portion;
- a rod shaped piece of lead writing material disposed in said passageway and extendable outwardly from said tip;
- means for advancing and withdrawing said piece of lead along said passageway and outwardly from said tip;
- said means for advancing and withdrawing said piece of lead writing material includes a gripping member having a tapered internal thread and a tapered screw member having a tapered external thread for engaging and disengaging said gripping member, said gripping member fixing said lead writing material in said passageway with a portion of lead writing material extending outwardly therefrom;
- and
- means including a coil spring, a longitudinally extending generally rectangular channel in said cylindrical barrel with a plurality of perpendicular stops and a follower within said channel and extending slightly therefrom for engaging said stops to thereby maintain a pre-selected force on said lead writing material.
3 more elements
Dependencies are inferred from the claim text.