Coaxial Tool Coupler for Zero Offset and Breakout Force

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Solution Overview

Problem

Conventional tool couplers introduce an offset between the linkage and the tool, reducing breakout forces and adding weight and cost to the machine.

Innovation Solution

A tool coupling assembly with a tool coupler that allows for coaxial pivotal mounting to a machine link, eliminating the offset by using a wedge mechanism to secure the tool pins and a power link system for zero offset connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional pin grabber coupler is used to connect the tool to the machine linkage, then the tool can be quickly and interchangeably connected, but an added offset distance is introduced between the end of the linkage and the pins on the tool, which reduces the overall breakout forces

Engineering Contradiction:
Improvequick and interchangeable tool connectionVSAvoidbreakout forces at the end of the tool
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The tool coupler is nested within the machine linkage structure, with the coupler frame positioned inside the linkage housing. The tool pins pass through both the coupler and linkage, nesting the coupler components within the existing linkage structure to eliminate offset while maintaining quick connection capability

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The coupler frame acts as an intermediary component that directly connects the tool pins to the machine linkage without introducing additional distance. The hooks on the coupler frame engage the tool pins while the coupler itself is mounted coaxially to the linkage, serving as a mediator that eliminates the offset problem of conventional couplers

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a conventional pin grabber coupler is used to connect the tool to the machine linkage, then the tool can be quickly and interchangeably connected, but additional weight and cost are added to the tool coupling arrangement

Engineering Contradiction:
Improvequick and interchangeable tool connectionVSAvoidweight of the tool coupling arrangement
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The coupler frame is merged with the machine linkage structure by mounting it coaxially to the linkage and integrating it into the existing housing. This merging eliminates the need for separate, bulky coupler components, reducing overall weight while maintaining quick connection functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The offset-introducing components of conventional couplers are extracted and eliminated. The design takes out the unnecessary distance elements and replaces them with a direct, coaxial mounting approach that reduces weight while preserving the quick connection capability

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Maintains breakout forces and reduces weight and cost by eliminating the offset, enabling efficient and quick tool changes without reducing mechanical performance.

Implementation Method 1

a wedge slidingly received within the coupler frame; and an actuator connected to the wedge to move the wedge away from the hook to bias the second pin of the tool against the coupler frame

Methodology Applied
Scientific EffectWedge mechanism: Wedge

Data Source

PatentEP3894637B1Tool coupling arrangement having zero offset
Publication Date: 2025.11.05 CATERPILLAR INC
  • EP3894637B1 patent drawingFigure 1
  • EP3894637B1 patent drawingFigure 2
  • EP3894637B1 patent drawingFigure 3

AI summary

A tool coupler for coupling a tool to an end of a machine link. The tool coupler having a coupler frame, a hook configured to receive a first pin of the tool and configured to attach to the end of the machine link such that the tool coupler, a wedge slidingly received within the coupler frame, and an actuator connected to the wedge to move the wedge away from the hook to bias a second pin of the tool against the coupler frame. The tool coupler mounts the tool to the machine link such that the tool and the tool coupler pivots about the same axis.