Bit Holder Shank Ribs Prevent Ejection in Milling Blocks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Road milling, mining, and trenching equipment face issues with bit holders and unitary bit/holders being ejected from bit holder blocks due to harsh operating environments, leading to wear and breakage, and a need for improved radial connection and force distribution to prevent ejection and enhance durability.
Innovation Solution
The design incorporates a bit holder with a cylindrical shank featuring a segment with ribs and notches or relief zones, which reduces surface contact and provides a more evenly distributed and concentrated force, forming an interference fit with the bit holder block bore to secure the bit holder in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bit holder is retained in the bit holder block using traditional methods, then the bit holder can be held in place, but the bit holder may be ejected from the bit holder block bore due to harsh operating conditions
Solution Approach 1:
The shank is divided into multiple segments with ribs that create localized contact points with the bore, distributing the retention force across multiple locations rather than relying on a single continuous contact surface
Solution Approach 2:
The ribs on the shank create localized areas of high contact pressure at specific points along the bore, providing enhanced grip and retention where needed most while maintaining overall structural integrity
2Force
If the shank has full surface contact with the bit holder block bore, then maximum radial force is provided, but surface contact causes wear and concentrated stress leading to ejection
Solution Approach 1:
The continuous surface contact is segmented into discrete rib structures, converting distributed pressure into concentrated contact points that maintain radial force while reducing cumulative wear
Solution Approach 2:
The ribs convert the potentially harmful concentrated stress that leads to wear into beneficial localized contact points that provide both retention force and reduced surface area for wear to occur
3Ease of manufacture
If the bit holder design is simplified without ribs or notches, then manufacturing is easier, but the bit holder cannot sufficiently prevent ejection in harsh conditions
Solution Approach 1:
The addition of ribs segments the shank surface, creating a structure that is still relatively simple to manufacture using standard machining processes while dramatically improving retention capability
Solution Approach 2:
The geometric parameters of the shank are modified by adding ribs with specific dimensions and spacing, changing the contact characteristics with the bore to provide superior retention without complex manufacturing requirements
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
This solution effectively prevents the ejection of bit holders and unitary bit/holders from the bit holder block bore, enhancing their durability and operational reliability in harsh conditions by distributing force more evenly and reducing wear.
Implementation Method 1
the base block comprising a bore adapted to make an interference contact with at least the segment of the shank
Data Source
AI summary
A unitary bit/holder and/or a bit holder including a body portion and a shank. The body portion and the shank being coaxial and including a bore extending from a forward end of the body portion to the distal end of the shank. The shank further including a segment adjacent a distal end of the shank that includes a plurality of ribs and at least one notch or relief zone between each rib in the plurality of ribs.