Hand Rivet Nut Tool Positioning Assembly Groove Design
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Solution Overview
Problem
Conventional hand rivet nut tools face challenges in stable positioning of the mandrel, leading to deformation issues and increased assembly complexity and cost due to the use of steel balls and helical springs, which result in poor positioning and potential sliding of the mandrel within the rotating sleeve.
Innovation Solution
A positioning assembly comprising a tubular rotating sleeve with a mounting groove and a resilient positioning ring that fits around both the rotating sleeve and the mandrel, providing stable line-contact and ensuring the mandrel is securely positioned, allowing for effective riveting of rivet nuts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steel balls and helical springs are used for positioning the mandrel, then the mandrel can be retained in the rotating sleeve, but the positioning stability is poor and sliding occurs
Solution Approach 1:
The patent removes the steel balls and helical springs from the positioning mechanism, replacing them with a simple groove structure. The mandrel has a groove formed on its outer surface that engages with a corresponding groove on the rotating sleeve, eliminating the need for retaining elements and achieving reliable positioning without sliding.
Solution Approach 2:
Instead of using protruding steel balls to engage with holes (as in conventional designs), the patent uses recessed grooves that interlock. This inverted approach provides more stable positioning because the grooves create line contact rather than point contact, preventing mandrel sliding while simplifying the overall structure.
2Reliability
If steel balls and helical springs are used for positioning, then the mandrel can be retained, but the assembly cost increases
Solution Approach 1:
The patent eliminates the need for steel balls and helical springs by using a groove-based positioning system. This reduces material costs and assembly complexity, making the manufacturing process simpler and more cost-effective while maintaining reliable mandrel positioning.
Solution Approach 2:
The groove structure is integrated directly into the mandrel and rotating sleeve as simple machined features, replacing expensive precision-assembled components like steel balls and springs. This approach uses inexpensive manufacturing processes (groove formation) to achieve the same positioning function at lower cost.
3Reliability
If steel balls are used for positioning, then the mandrel can be retained, but point-contact results in poor positioning effect
Solution Approach 1:
The patent inverts the conventional point-contact approach by using groove-based line contact. The groove on the mandrel engages with the groove on the rotating sleeve, creating extensive contact area that significantly improves positioning precision and eliminates the sliding issues associated with point contact.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution simplifies the assembly process, reduces costs, and enhances the positioning stability of the mandrel, enabling reliable and efficient riveting of rivet nuts on work pieces with reduced risk of sliding and improved line-contact for secure fastening.
Implementation Method 1
a resilient positioning ring that fits around both the rotating sleeve and the mandrel
Data Source
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AI summary
A positioning assembly of a hand rivet nut tool has a rotating sleeve (10), a mandrel (20) and a positioning ring (30). The rotating sleeve (10) has a mounting groove (102) formed around an inner surface of the rotating sleeve (10). The mandrel (20) is mounted through the rotating sleeve (10) and has a positioning groove (22) formed around an outer surface of the mandrel (20). The positioning ring (30) is mounted in and around the mounting groove (102) and the positioning groove (22). The mandrel (20) is stably held by the positioning ring (30), so the hand rivet nut tool is able to stably rivet a rivet nut on a work piece. The hand rivet nut tool with the positioning assembly has simplified and optimized positioning effect, and reduced assembling time and cost.