"This Recommended Practice applies to mobile hydraulic excavators which are either crawler or wheel mounted@ with or without outrigger members. ( A mobile hydraulic excavator is defined as ""a self propelled machine with an upper structure capable of continuous rotation and which digs@ elevates@ swings@ and dumps material by action of the boom and arm or telescoping boom with bucket."") Purpose The purpose of this Recommended Practice is to provide a uniform method of rating digging forces for mobile hydraulic excavators."