Comprehensive Guide to Pattern Changers in Heavy Equipment: Functionality, Types, and Practical Advice

[MikePhua]

Introduction to Pattern Changers
A pattern changer in heavy equipment, especially excavators and backhoe loaders, is a mechanical or electronic system that allows the operator to switch between different control joystick configurations, typically between the "SAE" (Society of Automotive Engineers) pattern and the "ISO" (International Organization for Standardization) pattern. This feature enhances operator comfort and efficiency by enabling them to use their preferred control style, which is crucial on sites where multiple operators with different experiences work with the same machine.
Pattern changers improve machine adaptability, reduce training time, and boost productivity by allowing easy switching of control schemes suited to specific operator preferences or regional norms.

Understanding Control Patterns: SAE vs ISO

• SAE Pattern (Cat Pattern or Backhoe Pattern):
  • Typically, the right joystick controls the boom (up/down) and bucket curl (open/close).
    
  • The left joystick controls the swing (rotation of the upper structure) and stick (dipper) movement.
    
  • This pattern is common among Caterpillar backhoes and many North American operators.
    
• ISO Pattern (John Deere Pattern or Excavator Pattern):
  • The right joystick controls the stick (dipper) and bucket curl.
    
  • The left joystick controls the boom (up/down) and swing.
    
  • This configuration is preferred by many outside North America and among operators familiar with excavators rather than backhoes.
    

Operators can find the difference quite significant, akin to "riding a bicycle with crossed arms," with muscle memory strongly influencing preference.

How Pattern Changers Work

• Mechanical Pattern Changers:
  • Earlier machines often use a physical lever or selector located under the operator seat or near the control console.
    
  • Switching involves unlocking the lever, physically moving it to the alternate position, and locking it back.
    
  • Some models may require loosening bolts or manipulating control linkages or pilot hoses for adjustment.
    
• Electronic/Digital Pattern Changers:
  • Modern excavators and backhoe loaders integrate pattern changers controlled via the cabin interface or operator display.
    
  • With a simple menu selection or touchscreen operation, the control scheme changes instantly without manual adjustments.
    
  • This system allows multiple operators to easily switch preferences between shifts or different projects.
    

Benefits of Pattern Changers

• Operator Familiarity and Comfort:
  Operators can use the control scheme they trained on, reducing errors and increasing confidence.
  
• Reduced Training Time:
  New operators require less time to adapt to equipment with familiar controls.
  
• Enhanced Productivity:
  Smooth operation with familiar controls translates to faster cycle times and efficient work.
  
• Improved Equipment Utilization:
  Machines can be shared across different operators without operational conflicts.
  
• Adaptability Across Regions:
  Different countries or companies often prefer a certain pattern; pattern changers accommodate this diversity.
  

Practical Suggestions and Considerations

• When purchasing or renting heavy equipment, verify if the machine supports a pattern changer, especially if multiple operators with varying experiences will use it.
  
• Operators should practice switching patterns during training sessions to become comfortable with both schemes.
  
• Maintenance teams should ensure the mechanical or electronic pattern changers are inspected regularly for wear or software updates to prevent malfunction.
  
• If a machine does not have a built-in pattern changer, retrofitting options may be available but require professional assessment due to hydraulic and electrical complexity.
  
• Consider the impact of pattern changes on auxiliary controls connected to attachments, ensuring no unintended operational conflicts occur when switching.
  

Terminology Explained

• Pattern Changer: A mechanism or system that swaps joystick control configurations between SAE and ISO patterns.
  
• SAE (Society of Automotive Engineers) Pattern: Traditional backhoe control scheme with right-side boom and bucket control.
  
• ISO (International Organization for Standardization) Pattern: Standard excavator control pattern with right-side stick and bucket control.
  
• Pilot Hoses: Hydraulic control lines that help direct fluid flow in proportional valves, sometimes needing manual rerouting in older pattern-changing methods.
  
• Joystick Configuration: The assignment of hydraulic functions to the left and right operator joysticks.
  

Real-World Insights and Stories

• A construction company managing a fleet of backhoe loaders reported improved operator satisfaction and reduced errors after equipping machines with pattern changers, facilitating seamless shifts between operators trained in different control schemes.
  
• An operator once shared their experience operating a rental excavator with the opposite control pattern: the initial confusion resulted in operational mistakes until the pattern changer was engaged, significantly improving control precision.
  
• Manufacturers like Caterpillar and John Deere have incorporated pattern changers as standard on many machines, recognizing operator preference diversity and the efficiency gains from flexible control options.
  
• Some older machines require manual intervention to change patterns, and operators must be trained not to exceed hydraulic system pressure limits during such adjustments to avoid damage.
  

Additional Parameters and Recommendations

• Always consult the equipment’s service manual before attempting to change the control pattern, especially for mechanical or hydraulic adjustments.
  
• Operators switching between patterns should familiarize themselves with safety controls and emergency procedures specific to each pattern to prevent accidents.
  
• After changing patterns, verify all control functions in a safe environment before starting productive work to avoid unexpected movements.
  
• Manufacturers often provide training resources or simulation software to help operators get accustomed to both control patterns effectively.
  

Summary
Pattern changers in heavy equipment play a crucial role in adapting machines to the preferred operator control schemes of either SAE or ISO patterns. This capability enhances operator comfort, productivity, and machine versatility across job sites and diverse operator backgrounds. Advances in electronic control systems have simplified pattern switching, allowing fast and safe transitions. Proper maintenance, operator training, and awareness of machine-specific procedures are vital to leverage the full benefits of pattern changers.
Understanding the differences between control patterns, their operational implications, and the benefits of flexibility enables operators, fleet managers, and technicians to make informed decisions, optimize machine use, and maintain safe, efficient jobsite operations.
This comprehensive overview equips stakeholders with foundational knowledge and practical guidance to effectively manage and utilize pattern changers in modern heavy equipment.