Tapered Threaded Liner Bolt for Jam-Free Mill Liner Removal
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Solution Overview
Problem
The existing liner bolts for grinding mills often become jammed during operation, requiring the use of impact tools for removal, which poses safety hazards and increases downtime, and previous quick release designs are prone to failures under load.
Innovation Solution
A liner bolt design featuring an elongate stud with a tapered head and internal thread, allowing for rotational removal without impact tools, utilizing a tapered threaded engagement between the stud and head to support loads and prevent breakages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liner bolts are used with a head received through the liner, then the bolt can be secured with a nut on the outside, but the bolt becomes jammed during operation requiring impact tools for removal
Solution Approach 1:
The bolt is segmented into two distinct parts: an inner bolt part received inside the liner and an outer bolt part extending outside the mill. These parts can be independently removed, allowing the inner part to remain secured while the outer part is easily detached for liner replacement without requiring impact tools.
Solution Approach 2:
The bolt design transitions from a static, permanently installed configuration to a dynamic, easily removable configuration. The quick release mechanism allows the bolt to transition between secured and removed states without impact forces, improving operational ease while maintaining reliability during grinding mill operation.
2Ease of manufacture
If impact tools are used to drive bolts inwardly during liner replacement, then the bolts can be installed, but safety hazards and increased downtime occur
Solution Approach 1:
The bolt is pre-configured with a quick release mechanism that eliminates the need for impact-driven installation. The outer bolt part can be simply pushed inwardly and secured with a nut, while the inner bolt part remains in place, allowing rapid liner replacement without time-consuming impact tool operations.
3Ease of operation
If a quick release liner bolt with narrowed portion is used, then rotational removal is enabled, but load-bearing capacity is reduced leading to breakages
Solution Approach 1:
The bolt is divided into inner and outer parts with distinct functions. The inner bolt part maintains full strength for load-bearing within the liner, while the outer bolt part provides the quick release capability. This segmentation allows rotational removal without compromising the load-bearing capacity of the critical inner portion.
Solution Approach 2:
The problematic narrowed portion is extracted from the design by separating the bolt into two parts. The quick release function is achieved through the outer part's ability to be independently removed, while the inner part maintains uniform cross-section for optimal strength, eliminating the need for load-critical narrowed sections.
Data Source
AI summary
A liner bolt (10) comprising an elongate stud (12) and a head (14) engageable with a first end (16) of the stud (12). The head (14) including an inwardly tapered first end portion (24) adjacent a first end (21) thereof. A threaded portion (18) is provided adjacent a second end (17) of the stud for receiving a nut (20). The first end (21) of the head (14) includes an inwardly tapered opening (28) having an internal thread (30) and the first end (16) of the stud (12) includes an inwardly tapered end portion (32) having an external thread (34) such that the first end (16) of the stud (12) is engageable in the opening (28) in the head (14).