Tapered Joint for Rapid Cone Arm Replacement
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Solution Overview
Problem
The existing weld-based cone arm assemblies in hole openers require skilled labor and significant time for replacement, leading to high costs and downtime, as they need to be removed and re-welded, limiting the number of replacements before the body itself requires rework, and are not suitable for switching between different cone arm types.
Innovation Solution
A two-part cone arm and pocket construction using a tapered section for securement and a keyed section for stress distribution and orientation, allowing cone arms to be easily replaced with fasteners without welding, featuring a pre-loaded fit that can create an interference lock for secure engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cone arms are welded into pockets of the hole opener assembly, then structural integrity and stress distribution are improved, but replacement time and labor cost increase significantly
Solution Approach 1:
The cone arm assembly is divided into separable components (cone arm and hole opener body) that can be easily disconnected through the rapid exchange mechanism, allowing the cone arm to be replaced without welding while maintaining structural integrity through the tapered fit and retention features
Solution Approach 2:
The connection system transitions from a static welded joint to a dynamic rapid-exchange mechanism that allows easy insertion and removal of the cone arm through axial loading and tapered geometry, enabling quick replacement while maintaining strength during operation
2Strength
If cone arms are welded into the body, then stress distribution is improved, but the number of replacement cycles before body rework is limited
Solution Approach 1:
By separating the cone arm from the body through non-permanent retention features (tapered fit with fasteners), the design allows multiple replacement cycles of the cone arm without degrading the body structure, effectively extending the body's service life while maintaining proper stress distribution during each operational cycle
3Strength
If welding is used to secure cone arms, then connection strength is improved, but adaptability for switching cone arm types is reduced
Solution Approach 1:
The rapid exchange mechanism enables dynamic reconfiguration of the hole opener by allowing easy removal and installation of different cone arm types through axial loading and tapered geometry, providing adaptability for switching applications while maintaining connection strength during operation
Solution Approach 2:
The standardized tapered fit and retention feature design creates a universal interface that accommodates different cone arm types and specifications, allowing the same hole opener body to work with various cone arm configurations for different cutting applications
4Productivity
If multiple cone arms and bodies are kept on site for rapid replacement, then downtime is reduced, but inventory cost and complexity increase
Solution Approach 1:
The separable design with standardized retention features allows for modular inventory management where cone arms can be independently stored and replaced, reducing the need to maintain complex inventories of complete assembled hole openers while still enabling rapid replacement to minimize downtime
Data Source
AI summary
A hole opener includes a body with cone arms. The body includes pockets formed in the body in which each of the pockets includes a forwardly-positioned shoulder pocket section, a rearwardly-positioned tapered pocket section and a base opening axially extending through a wall of the corresponding pocket that receives a fastener therethrough. The cone arms each include a cone head attached to an arm. The arm includes a forwardly-positioned shoulder arm section, a rearwardly-positioned tapered arm section, and a rearwardly-facing opening axially extending through the rearwardly-positioned tapered arm section that receives the fastener. When each of the cone arms is inserted into a corresponding one of the pockets and the corresponding fastener(s) is/are tightened, the rearwardly-positioned tapered arm section is securely drawn into the rearwardly-positioned tapered pocket section of the pocket to create a pre-loaded fit therebetween and the forwardly-positioned shoulder arm section mates with the forwardly-positioned shoulder pocket section.