Contoured Double Pass Roller Path Pin Retention
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Solution Overview
Problem
Current track chain designs face issues with pin retention, leading to loose pins and maintenance challenges, and are prone to fracturing or spalling under stress, especially in uneven terrain or high-load conditions.
Innovation Solution
A pin retention design using a bolt, washer, nut, and spacer system that prevents pin egress and incorporates a contoured roller path and Y-shaped lug configuration to distribute stress, reducing the likelihood of pin loosening and track chain member failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a snap ring with a welded plate is used to retain the pin, then the pin is prevented from falling out, but servicing the pin becomes difficult due to the welded plate
Solution Approach 1:
The retention system is divided into separate components: the snap ring remains in the groove while the plate is removed, allowing the pin to be serviced by simply removing the snap ring without dealing with a welded plate
Solution Approach 2:
The welded plate component is extracted/removed from the design entirely. The snap ring alone provides the retention function without requiring a welded plate, simplifying the structure and improving serviceability
2Ease of repair
If the welded plate is removed to improve servicing, then pin access is improved, but the snap ring is more likely to twist out of its retention groove
Solution Approach 1:
The snap ring is designed with features that pre-position and secure it in the groove before any servicing operations occur, preventing it from twisting out during maintenance activities
Solution Approach 2:
The snap ring cross-section is substantially round rather than flat, providing inherent stability and resistance to twisting while maintaining reliable engagement with the groove, eliminating the need for a welded plate
3Strength
If the track chain member is hardened to withstand stress concentrations, then resistance to fracturing and spalling is improved, but achieving the desired hardening depth becomes difficult
Solution Approach 1:
Instead of hardening the entire track chain member, only the specific areas subject to high stress concentrations are hardened, achieving the required strength where needed while avoiding the manufacturing difficulties of uniform deep hardening
Solution Approach 2:
The track chain member is pre-hardened in critical areas before assembly, so that when installed and subjected to loads, these pre-hardened zones resist fracturing and spalling without requiring difficult post-installation hardening operations
Data Source
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AI summary
A track chain member (400) comprises a shoe member (402), and a first rail member (404) extending from the shoe member (402), wherein the first rail member (404) defines a track chain traveling direction (T, 114) and a lateral direction (L) generally perpendicular to track chain traveling direction (T, 114), a first support surface (406) extending generally in both the track chain traveling direction (T, 114) and the lateral direction (L) defining an outer lateral extremity (408), and a first crest shaped member (410) disposed laterally adjacent the outer lateral extremity (408) of the first support surface (406).