Work Machine Swing Lock Controller with Positional Feedback

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Solution Overview

Problem

Existing systems for controlling the movement of upper frames and arm assemblies in machines like excavators lack a precise and efficient method to lock or restrict movement during transportation, leading to potential accidental movement of work tools and booms.

Innovation Solution

A control system with a controller that responds to user commands to lock or restrict the upper frame relative to the lower frame and arm assembly, using a swing lock button activated for less than a predetermined time for one command and longer for another, allowing independent control of the arm assembly and limiting rotational speed as the upper frame approaches a predetermined position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking system is used to prevent accidental movement of the swivel body and boom during transportation, then safety and stability are improved, but the ability to move the work tool and boom when needed (operational flexibility) deteriorates

Engineering Contradiction:
Improveprevention of accidental movementVSAvoidability to move work tool after positioning
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The locking system transitions from a static locked/unlocked state to a dynamic multi-state system where the swivel body can be locked at predetermined positions (0°, 90°, 180°, 270°) while still allowing movement between these positions. The controller dynamically adjusts locking engagement based on the swivel body's rotational position and operator commands, enabling both stable transportation locking and flexible operational movement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of locking engagement from binary (locked/not locked) to variable states based on rotational position. The locking mechanism engages at specific angular positions (0°, 90°, 180°, 270°) and disengages at intermediate positions, allowing the operator to lock the swivel body at predetermined orientations during transportation while maintaining the ability to rotate and reposition during operation.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a locking mechanism engages automatically when the swivel body reaches a predetermined position, then positioning precision is improved, but the risk of unintended engagement causing vibrations or damage deteriorates

Engineering Contradiction:
Improvepositioning accuracyVSAvoidvibrations and potential damage from unintended engagement
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The controller continuously monitors the rotational position of the swivel body and provides feedback to determine when predetermined positions (0°, 90°, 180°, 270°) are reached. This feedback mechanism ensures that the locking mechanism engages only at the correct positions and only when appropriate, preventing unintended engagement that could cause vibrations or damage while maintaining precise positioning accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system prepares for locking engagement by monitoring the approach to predetermined positions and can limit the rate of rotational movement as the swivel body approaches these positions. This preliminary action allows the operator to slow down before engagement, preventing sudden locking that could cause vibrations or damage while ensuring accurate positioning when locking does occur.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the locking system restricts movement of the upper frame and arm assembly simultaneously, then transportation safety is improved, but operational efficiency deteriorates

Engineering Contradiction:
Improvetransportation safetyVSAvoidoperational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The locking control is segmented into independent functions: swivel body locking and arm assembly locking. The controller can selectively engage the swivel body locking mechanism while leaving the arm assembly unlocked, or vice versa. This segmentation allows the operator to lock only the necessary components during transportation while maintaining full operational capability of the arm assembly when needed, thereby improving transportation safety without sacrificing operational efficiency.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3228761B1Control system for a work machine
Publication Date: 2019.10.30 CATERPILLAR INC
  • EP3228761B1 patent drawingFigure 1
  • EP3228761B1 patent drawingFigure 2
  • EP3228761B1 patent drawingFigure 3

AI summary

A control system for a work machine having an upper frame rotatably mounted to a lower frame is provided. The upper frame includes an arm assembly. The system includes a controller. The controller is responsive to a first user command to lock or substantially restrict movement of the upper frame relative to the lower frame while allowing user control of the arm assembly.