The tensioner's bent double-arm design uses two chain wheels or a combination of belt pulleys/flat rollers to compensate for slack in three different areas when a belt or chain is elongated due to extended wear and use. Stainless-steel construction protects the part from chemical attack, abrasives, and adverse weather conditions. Rubber suspension elements dampen and silence while extending the life span of the tensioner and surrounding equipment parts. Rubber inserts located between the outer housing and inner square-section tube are offset at a 45° angle, which functions like a torsion spring, pivot bearing, and vibration damper, all in one. Two models are available: the simple Boomerang and the belt-tensioning Boomerang. The simple model, for chain tensioners, is equipped at both arm ends with a standardized sprocket wheel. The belt-tensioner version is used in poly V-type belt drives for double roller pressure into the profile on the belt back.

Lovejoy Inc., 2655 Wisconsin Ave., Downers Grove, IL 60515, (630) 852-0500,