An instrument for removing tissue samples from a tissue mass which automatically penetrates, severs, and removes a tissue portion for examination. The instrument is motor powered, preferably by self-contained rechargeable batteries, and employs electrically actuated stops to control the action of penetration...http://www.google.ca/patents/US5249583?utm_source=gb-gplus-sharePatent US5249583 - Electronic biopsy instrument with wiperless position sensors
