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This document and the information contained herein, is the exclusive property of R&M Materials Handling Inc. and represents a non-public, confidential and proprietary trade
secret that may not be reproduced, disclosed to third parties, altered or otherwise employed in any manner whatsoever without the express written consent of R&M Materials
Handling Inc. Copyright 2020 © R&M Materials Handling Inc. All rights reserved.
2.6.1
Duty group
When the product is designed and purchased, the predicted lifetime of the product is agreed, based on the
expected use of the product. This expected use is known as the duty group. Hoisting machinery which is used
continuously to lift heavy loads is clearly in a very different duty group to a product of the same size which is used
occasionally just to lift light loads. While the product is used in accordance with the designed duty group, the
expected lifetime should be reached.
It is the owner’s responsibility to ensure that the product is used according to the duty group that it has been
designed for. By doing so, the product should reach the original predicted lifetime.
WARNING
Do not allow the product to be used outside the limits of the specified duty
group. Doing so, raises the risk of mechanical failure and can shorten the
product’s lifetime.
DANGER
EXCEED
ING THE PRODUCT’S SP
ECIFIED DUTY GROUP COMBINED WITH THE
LACK OF MAINTENANCE CAN LEAD TO A RISK OF A CATASTROPHIC
FAILURE.
The duty group is based on many factors including the hardware, the predicted lifetime, the number of shifts and
lifts, the distances traveled, the ratio of heavy to light items lifted and the environmental conditions the product is
used in. Notice that, if you moved from single-shift working to three-shift working, you would need to reduce the
loads or distances lifted and/or traveled in order to remain within the requirements of the duty group.
Parameter
Variables
Light use and heavy use
Lifting height and working
distances
Actual hoisting time and the average
distances being traveled by the trolley and
lifting devices.
Operating environment
The product is designed to work within
specific parameters of temperature,
humidity and cleanliness.
Product process
The number of shifts.
