Contacting Device Plunger Head Element Shrink Fit
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Solution Overview
Problem
Conventional pin probes face issues such as high material waste, long manufacturing time, high storage costs, risk of accidents due to loose probes, high electric resistance, and unreliable measurements due to 'wiggle' and wear, especially when dealing with various head types and small test points.
Innovation Solution
The method involves connecting the head element and plunger using press fitting or shrink fitting, allowing for separate material selection and reduced waste, with a guiding flange portion for improved contact and stability, enabling the use of durable materials like palladium alloys and reducing the need for integral head units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the head unit is made as an integral piece with the plunger, then the manufacturing process is simplified, but a large amount of waste material is generated and manufacturing time increases
Solution Approach 1:
The head unit is divided into two separate components: the plunger and the head element. The plunger is inserted into the tube element first, then the head element is attached to the plunger's end portion. This segmentation allows each component to be manufactured separately with optimized material usage, eliminating the excessive material waste associated with machining an integral head unit from a large-diameter stock.
2Strength
If the head unit is made as an integral piece with the plunger, then structural integrity is improved, but manufacturing duration increases
Solution Approach 1:
The head unit is segmented into the plunger and head element, which are manufactured separately and then assembled. This allows parallel manufacturing of components, significantly reducing total manufacturing time compared to machining an integral piece. The connection between plunger and head element is secured through the resilient element and flange structure, maintaining structural integrity during use.
3Reliability
If conventional rolling closure is applied, then the pin probe body is sealed, but the gap between plunger and body increases causing wiggle and measurement errors
Solution Approach 1:
A resilient element (spring) is introduced as an intermediary component between the plunger and the tube element's closed end. This resilient element provides continuous contact pressure, maintaining both sealing effectiveness and precise axial positioning of the plunger. The flange portion on the plunger works with the resilient element to eliminate gaps and prevent lateral movement, thereby eliminating 'wiggle' and ensuring measurement accuracy.
4Manufacturing precision
If the plunger diameter is kept small for precision, then the contact surface area is reduced, but electric resistance increases
Solution Approach 1:
The tube element is designed to serve multiple functions: it provides mechanical guidance for the plunger, electrical conduction path, and structural housing. By making the tube element electrically conductive and establishing direct contact between the tube element and the head element (through the resilient element and flange structure), the system achieves low electrical resistance without requiring an increased plunger diameter, thus maintaining measurement precision.
5Adaptability or versatility
If various head types are kept in stock for different applications, then adaptability is improved, but storage and manufacturing costs increase
Solution Approach 1:
The head unit is segmented into a standardized plunger and interchangeable head elements. The plunger serves as a common base component that can be used with different head element types. This allows the system to achieve versatility across multiple applications while maintaining a smaller inventory footprint, as only head elements need to be varied rather than complete assembled probes.
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
This approach results in a contacting device with reduced material consumption, longer service life, improved durability, and enhanced measurement accuracy by minimizing 'wiggle' and wear, while allowing for the economical use of advanced materials.
Implementation Method 1
a resilient element 20' arranged in an inner space of a tube element 10' (closed at one side) of the pin probe shown in Fig. 13. The resilient element 20' is biased by a plunger 14' inserted from the front into the tube element 10'
Implementation Method 2
Before closing-rolling the body, the spring is biased, followed by closing the pin probe body from the front applying rolling
Data Source
Figure 1~4
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Figure 8~12
AI summary
The invention is a contacting device suitable for measurements and/or other contact tests, the device comprising a head unit comprising a plunger (14) having a broadened portion (28) at its first end, and a head element (16) being on a second end of the plunger (14); a tube element (10) having a third end and a fourth end opposite the third end, receiving the broadened portion (28) of the plunger (14) at the third end, and keeping the broadened portion (28) in its inner space by means of an inward-projecting flange portion (18) arranged at the third end; and a resilient element (20) being arranged in the inner space of the tube element (10) being supported against the end portion of the broadened portion (28) and against the closed fourth end of the tube element (10). The second end of the plunger (14) projects out from the tube element (10) in case the broadened portion (28) is abutted against the flange portion (18). In the contacting device according to the invention the head element (16) and the second end of the plunger (14) are connected to each other by shrink fitting or by press fitting. The invention is, furthermore, a head unit for a contacting device, and methods for manufacturing a contacting device and a head unit.