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作者

来源

URBAN FORESTRY & URBAN GREENING,Vol.42,P.31-38

语言

英文

关键字

Rigging; Friction; Arborist block; X-Rings; FORCES

作者单位

[Kane, Brian] Univ Massachusetts, Dept Environm Conservat, 160 Holdsworth Way, Amherst, MA 01003 USA. Kane, B (reprint author), Univ Massachusetts, Dept Environm Conservat, 160 Holdsworth Way, Amherst, MA 01003 USA. E-Mail: Bkane@eco.umass.edu

摘要

Rigging is a dangerous arboricultural practice that involves working at height with sharp tools; it also induces large forces and dynamic motion of both the rigged piece and the tree itself. Manufacturers have recently developed alternatives to conventional arborist rigging blocks (with a rotating sheave) with the intention of increasing friction in the block to reduce the likelihood of anchor failure in the tree. We measured tension in the fall and lead of rigging ropes run through a variety of blocks (with and without rotating a sheave) in three test methods-dropping, raising, and lowering a mass. The ratio of tension in the lead to tension in the fall of the rope differed among test methods, blocks, ropes, and their interaction. Some of the differences were expected from the underlying physics, but it was not true that blocks without a rotating sheave consistently provided more friction. Considering the inconsistent findings, rigging a less massive piece seems to be a better way to reduce the likelihood of anchor failure than managing friction in the block.