Case Study: Coupling Guards for Pump and Motor Assembly

The Challenge

Machine Guard & Cover Co. was asked by the Army Corps of Engineers in Sault Ste. Marie, Michigan, to bring seven pump and motor coupling assemblies up to current ANSI B11.19-2010 guarding safety standards. The couplings were covered by bent metal covers that were installed years ago and no longer provided adequate protection for operators as they had large gaps near the spinning shafts of the pumps and motors. One assembly was found to have a three inch gap between the motor and guard.

Background & Requirements

New guards to safely cover the couplings and rotating shafts would need to be fabricated and installed to provide physical guarding that adhered to current ANSI B.11 standards.


Machine Guard & Cover Co. considered three options for covering the couplings:

  • Fabricated Box Guard: This style of guard is very efficient and cost effective when the installations require slightly different sizes as the box can easily be modified during fabrication. This guard can be somewhat oversized to a specific application however.
  • Custom Coupling Cover: This style of guard is cost effective when many copies of the same part are required and the size of the guard is the same across all installations. A mold is created that then is used to vacuum-form the guard.
  • Coupling Cover Kit: This style of guard contains separate top, ends and sides and is used when each application is unique, and requires modifications and customizations during each installation.


With the seven installations having little deviation from each other, a custom coupling cover was tooled and molded to be used on all locations.

Coupling Guards for Pump and Motor Assembly, Before and After

The guards were installed and provided the correct tolerances for ANSI B.11-2010 guarding standards while providing a cost effective and time efficient solution.