Slotted Retainer for Rotating Bit Sealing
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Solution Overview
Problem
In road milling, mining, and trenching equipment, the gap between the bit and the retainer increases over time, allowing debris to enter and reducing the life of the bit and its components, leading to premature wear and replacement.
Innovation Solution
A slotted retainer with varying features at the distal end, including a chamfer and axial slots, provides a nearly 100% sealed interface between the bit and the retainer, reducing axial movement and enhancing bit rotation, thereby extending the life of the bit, bit holder, and base block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional retainer is used to hold the bit, then the bit can be retained in the bit holder, but over time a gap forms allowing debris to enter, reducing bit rotation quality and component life
Solution Approach 1:
The retainer is divided into multiple segments or slots that can move relative to each other, allowing the structure to adapt and maintain sealing contact with the bit shank despite wear and dimensional variations, preventing debris from entering through gaps
Solution Approach 2:
The retainer transitions from a static rigid structure to a dynamic flexible structure that can deform and adjust its position to maintain continuous contact with the bit shank, ensuring debris-free operation throughout the component's service life
2Ease of operation
If the retainer is made loose to accommodate wear, then insertion is easier, but axial movement increases and bit rotation is inhibited
Solution Approach 1:
The retainer is designed with flexible segments that allow easy insertion through deformation, then lock into position to prevent axial movement, ensuring both ease of installation and optimal bit rotation during operation
Solution Approach 2:
The retainer's physical parameters (shape, position) change during insertion to accommodate the bit, then stabilize to provide the correct clearance for optimal rotation, dynamically adjusting to maintain both ease of operation and productivity
3Duration of action of moving object
If the gap between bit and retainer increases, then wear is reduced, but debris enters the interface and accelerates wear of the bit holder bore
Solution Approach 1:
The retainer structure is segmented to allow controlled movement and wear distribution across multiple contact points, preventing concentrated wear while maintaining a debris-free sealing interface through the slots
Solution Approach 2:
The retainer acts as an intermediary element between the bit and bit holder, absorbing wear through its flexible segments while maintaining a sealed interface that prevents debris from accelerating wear of the bit holder bore
Data Source
AI summary
A retainer for a rotating bit and/or pick that includes a slot extending from a forward end of the retainer to a distal end of the retainer and a lead in chamfer extending from a distal end of the retainer to an out surface of the retainer. The slot includes a gap profile formed by the configuration or design of a first radial end surface of the slot and a second radial end surface of the slot. The retainer can also include any of or any combination of a dual corner break, a relief notch extending from the distal end of the retainer, a pair of cutouts, a pair of arms, at least one tab, and a compression slot. The retainer may be used independently with the rotating bit or it may be used in conjunction with nearly butted or solid generally cylindrical hollow spacers and/or washers.