Traction Drum or Sheave Hoist : A device that does not accumulate the suspension rope but is designed to climb the rope by the application of a friction force between the rope and the drum or sheave
Spider, A Division of Safeworks, Glossary of Powered Access & Safety Terms, WA 98188, USA 2004. www.spiderstaging.com, http://www.spiderstaging.com/PDF%20Files/Catalog/A ppendix%20-%20Glossary%20of%20Powered%20Access%20S afety%20Terms.pdf, (Pwr Suspended Access Safeworks in Spiderstaging and Spiderbasket Usage - Amer) {466}