F. Flying & Rigging Systems
Sheave
sheave, pulley wheel, stage pulley
What is a Sheave?
A sheave (pronounced "shiv") is a grooved wheel designed to guide and redirect a rope or cable. Sheaves are the fundamental pulley elements in stage flying systems, found in head blocks, loft blocks, floor blocks, and tensioning devices.
Key Specifications
| Parameter | Typical Range |
|---|---|
| Diameter | 150mm – 600mm |
| Groove Profile | Matched to rope diameter |
| Material | Cast iron, steel, or nylon |
| Bearing | Plain bushing or ball bearing |
Key Concepts
D/d ratio ruleThe sheave-to-rope diameter ratio must be ≥ 16:1 for wire rope to prevent premature rope fatigue. For example, a 10mm rope requires a minimum sheave diameter of 160mm.