Cylindrical Tool Bit Shank Design for Wear Resistance

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Solution Overview

Problem

Serrated cutting edges on motor grader blades wear out quickly due to abrasive materials, necessitating frequent replacement and are often expensive due to complex geometry and costly inserts.

Innovation Solution

A tool bit with a cylindrical shank and working portion, featuring a flat bottom surface and cross-hole, designed for attachment to a blade assembly, allowing for cost-effective manufacturing and potential insert integration for enhanced durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If serrated cutting edges are provided to improve penetration, then cutting performance is improved, but the teeth wear out quickly due to abrasive materials

Engineering Contradiction:
Improvecutting performanceVSAvoidwear life
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The blade is divided into multiple replaceable tool bits with individual cylindrical teeth, allowing selective replacement of worn teeth without replacing the entire blade assembly. This segmentation enables maintenance of cutting performance while extending overall blade system life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the geometric parameters of the cutting teeth from traditional serrated edges to cylindrical profiles with specific diameter ratios (working portion diameter greater than shank portion diameter). This parameter change optimizes both penetration capability and wear resistance.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If complex geometry is machined onto tool bits after forging, then cutting performance is improved, but manufacturing cost increases

Engineering Contradiction:
Improvecutting performanceVSAvoidmanufacturing cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The cutting teeth are designed with cylindrical curvature rather than complex angular geometry. This allows the teeth to be manufactured using simpler forming processes and reduces the need for expensive post-forging machining operations while maintaining effective cutting performance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

By defining specific cylindrical geometric parameters (diameter ratios between working and shank portions), the invention simplifies the manufacturing process while ensuring optimal cutting performance through standardized, easily manufacturable shapes.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If inserts or tiles of hardened material are placed at the tip of tool bits, then durability is improved, but cost increases

Engineering Contradiction:
Improveuseful lifeVSAvoidcost
Core Design Contradiction:
Duration of action of moving objectVSEase of manufacture

Solution Approach 1:

Instead of using expensive hardened inserts, the invention achieves localized durability by optimizing the cylindrical geometry of the tooth itself, with the working portion having a larger diameter than the shank portion. This geometric optimization provides the necessary durability without requiring additional hardened material inserts.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention employs simpler, more cost-effective tool bit designs that can be replaced or reconfigured as needed, rather than relying on expensive hardened inserts. The cylindrical geometry provides sufficient durability for the application while maintaining lower manufacturing costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP3775400B1Tool bit having a cylindrical profile and blade assembly
Publication Date: 2023.10.04 CATERPILLAR INC
  • EP3775400B1 patent drawingFigure 1
  • EP3775400B1 patent drawingFigure 2
  • EP3775400B1 patent drawingFigure 3

AI summary

A tool bit (200, 300, 400, 500) comprises a shank portion (202, 302, 402, 502) including a cylindrical configuration defining a longitudinal axis (L), a radial direction (R), and a circumferential direction (C), and a working portion (204, 304, 404, 504) including a cylindrical configuration that is concentric with the shank portion (202, 302, 402, 502) and a flat bottom surface (218, 318, 418, 518).