Self-Closing Tap Cartridge for Stable Plunger Positioning
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Solution Overview
Problem
Existing self-closing taps face issues with unintentional alteration of the longitudinal position of the plunger on the piston shaft due to vibrations and asymmetric forces, which can lead to inconsistent closure times and mechanical failure of the set screw and adhesive solutions used to prevent this.
Innovation Solution
The self-closing tap design incorporates a tap handle interface with recesses that prevent rotation of the plunger and piston shaft, ensuring the longitudinal position of the plunger remains fixed, using a helical thread engagement for secure alignment and minimizing parts and complexity, thus avoiding mechanical failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If set screw and adhesive are used to fix plunger position, then plunger position stability is improved, but device complexity and risk of mechanical failure increase
Solution Approach 1:
The piston shaft is segmented into two functional portions: a first portion that rotates with the tap handle to advance the plunger, and a second portion with an engagement end that has a non-circular cross-section. This segmentation allows the plunger to be securely positioned without additional fastening components, resolving the contradiction by eliminating set screws and adhesives while maintaining position stability.
Solution Approach 2:
The engagement end of the piston shaft features a non-circular cross-section (asymmetric geometry) that prevents rotation of the plunger relative to the piston shaft. This asymmetric design inherently secures the plunger position without requiring additional fastening elements, thereby reducing device complexity while improving position stability.
2Stability of the object's composition
If set screw and adhesive are used to prevent rotation, then plunger position stability is improved, but reliability under vibration decreases
Solution Approach 1:
The non-circular cross-section of the engagement end creates an asymmetric mechanical interface that prevents relative rotation between the plunger and piston shaft through geometric constraint. This design is inherently resistant to vibration and mechanical failure because it relies on structural geometry rather than adhesive bonds or threaded fasteners that can fail under vibrational stress.
Solution Approach 2:
The engagement end's non-circular geometry enables the plunger to self-lock in position through its own structural features without requiring external fastening components. The plunger's square or rectangular cross-section fits into the corresponding recess in the piston shaft, creating a self-servicing connection that maintains reliability under vibration.
3Manufacturing precision
If helical thread engagement is used, then plunger positioning precision is improved, but device complexity increases
Solution Approach 1:
The helical thread engagement feature is merged with the engagement end's non-circular cross-section into a single integrated structural element. This combination achieves precise plunger positioning through the helical thread mechanism while the non-circular geometry prevents over-rotation, thereby maintaining positioning precision without requiring separate complex fastening systems.
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 design effectively prevents unintentional alteration of the plunger position, ensuring consistent closure times and reducing the risk of mechanical failure, even under conditions of extended or violent vibrations, without requiring set screws or adhesives.
Implementation Method 1
The first portion of the piston shaft has a helical thread on the outside face of the piston shaft, and the fixing of the plunger to the piston shaft is via the engagement of the helical threads of the bore and the first portion of the piston shaft
Implementation Method 2
The first recess is adapted to receive the engagement end of the piston shaft and prevent rotation of the piston shaft around its longitudinal axis, and the second recess is adapted to receive at least the second end of the plunger and to prevent rotation of the plunger around the piston shaft
Data Source
Figure 1~2
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AI summary
A self closing tap (102) comprising a cartridge (12) and a tap handle interface. The cartridge (12) comprises a piston (122) and a plunger (32). The piston (122) is comprised of a piston head (124), and a piston shaft (126), the piston shaft (126) has a longitudinal axis (A) and is fixed to the piston head (124) at a first end, and the second end of the piston shaft (126) is an engagement end (182). The plunger (32) is movably fixed to a first portion of the piston shaft (126) and adapted to move longitudinally along the first portion of the piston shaft (126). The plunger (32) has a first and second end, wherein the second end of the plunger (32) is closer to the engagement end (182) of the piston shaft than the first end, wherein the tap handle interface comprises a first and second recess (186, 154), wherein the first recess (186) is adapted to receive the engagement end (182) of the piston shaft (126) and prevent rotation of the piston shaft (126) around its longitudinal axis (A), and the second recess (154) is adapted to receive at least the second end (126) of the plunger (32) and to prevent rotation of the plunger (32) around the piston shaft (126).