I want to share with the readers of his instrument who successfully work for a long time. Similar design available to me in the literature I have not met.
As you know, when you create drawings the designer requires pencils of different hardness in Order to combine the most used ones in one tool, I made clutch pencil with two mechanisms of attachment of the leads at opposite ends (see drawing), which allow you to have two stylus different hardness or sharpening, which is very convenient.
Double sided collet:
1 — head collet clamps; 2 — the United body of the pencil, 3 — bushings-limit switches collet mechanisms, 4 — Cam, 5 — axis Cam, 6 — lead, 7 — stylus sharpening “spatula”
For compression collets between them is eccentric, turning the wheel which is 90°, we get the opportunity to produce or supply a replacement stylus Alterations are minor and quite affordable for the manufacture of Amateur designers Will be very happy. if this is of interest to readers.
N. SEROV, design engineer, Privolzhsk, Ivanovo oblast