Patent ID: 8128302

Claim:
A writing instrument, comprising: a substantially tubular body extending between a top and a writing end, and an elongate slot disposed in an outer surface of the body, the slot having a first detent defined at a first end of the slot proximate to the top and a second detent defined at a second end of the slot proximate to the writing end; and a substantially tubular open-ended cap disposed coaxially around the body and having a cut therein that defines an elongate arm having a first end and a second end, the arm being connected to the cap at the first end and having an inwardly-oriented protrusion at the second end sized to engage the first and second detents at the first and second ends of the slot, wherein the cap is slidable along the body from the first end of the slot to the second end of the slot such that the inwardly-oriented protrusion is configured to slide along the slot until the protrusion engages the second detent at the second end of the slot which retains the cap in a closed position, in which the cap covers the writing end, and wherein the cap is slidable along the body from the second end of the slot to the first end of the slot such that the inwardly-oriented protrusion is configured to slide along the slot until the protrusion engages the first detent at the first end of the slot which retains the cap in an open position in which the writing end is exposed.