Impact Tool Anvil Transition Region Stress Reduction
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Solution Overview
Problem
Impact tool anvils experience stress degradation due to interaction with sockets and hammers, leading to reduced operational life, as conventional transition regions with abrupt geometric changes concentrate stress and cause material weakening.
Innovation Solution
The design incorporates a transition region with a sweeping radius surface and angular transition, which reduces stress concentrations by smoothing the transition between the faceted drive end and the shaft body, including features like a stop surface and chamfered edges to manage stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a conventional transition region with abrupt geometric changes is used, then the manufacturing process is simple, but stress concentrations occur leading to material weakening and reduced operational life
Solution Approach 1:
The patent applies curvature by replacing abrupt geometric changes with a transition region that features a sweeping radius surface. This curved transition smoothly connects the faceted drive end to the shaft body, eliminating sharp corners and edges that concentrate stress. The sweeping radius surface creates a gradual geometric progression that distributes stress more evenly throughout the transition zone, directly addressing the stress concentration problem while extending operational life.
Solution Approach 2:
The patent changes geometric parameters by introducing a transition region with specific dimensional characteristics. The sweeping radius surface is defined by its radius and axial length, creating a controlled geometric transition zone. This parameter-based approach allows for optimization of the transition region's dimensions to achieve the desired stress distribution while maintaining manufacturability, resolving the contradiction between simplicity and durability.
2Strength
If a transition region with sweeping radius surface and angular transition is used, then stress concentrations are reduced by up to 37%, but the manufacturing process becomes more complex
Solution Approach 1:
The patent segments the transition region into distinct functional surfaces: a sweeping radius surface that provides the primary curved transition, and an angular transition surface that completes the connection to the shaft body. This segmentation allows each surface to be optimized independently for stress distribution, while the modular nature of these surfaces can facilitate staged manufacturing processes, addressing both strength requirements and manufacturability concerns.
Solution Approach 2:
The patent applies different geometric qualities to different regions of the transition zone. The sweeping radius surface provides a smooth, curved transition in one area, while the angular transition surface provides a controlled angular connection in another area. This local differentiation of geometric properties allows each region to perform its specific function optimally - the curved surface for stress distribution and the angular surface for structural connection - while collectively achieving the desired mechanical integrity.
Data Source
AI summary
Systems and methods for management of material stresses present at transitions between facets of an anvil and the anvil shaft are described. In one aspect, an apparatus includes an impact tool anvil extending along an axis of extension and having a faceted drive end and a shaft body which is connected to the faceted drive end through a transition region that couples respective faces of the faceted drive end to the shaft body, the transition region including a sweeping radius surface having a first axial end and a second axial end, the first axial end connected to a respective face of the faceted drive end, the first axial end having a tangency with the respective face of the faceted drive end; and an angular transition having a slope that radially rises from the second axial end of the sweeping radius surface to the shaft body.