Fluid Dispenser Neck Thread Profile for Easy Rescrewing
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Solution Overview
Problem
Existing fluid product dispensers with deformable and malleable skirts cannot be easily rescrewed due to tight contact, relaxation of the skirt, and flexible tabs that hook onto the neck threads, making them difficult to reuse.
Innovation Solution
The dispenser features helical threads on the neck with an upper screw start, a lower thread end, and an intermediate portion with a cross-section that decreases in the unscrewing direction and increases in the screwing direction, reducing unscrewing torque and increasing rescrewing torque, thereby facilitating easy rescrewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the skirt is made tight against the neck for secure engagement, then fastening reliability is improved, but clearance disappears making rescrewing impossible
Solution Approach 1:
The patent applies local quality by creating non-uniform clearance distribution along the thread engagement zone. The tapered thread profile provides different clearance characteristics at different axial positions, with greater clearance at the start of engagement and tighter contact at full engagement, enabling both reliable fastening and rescrewing capability.
2Ease of manufacture
If the flexible tabs are separated by slots to allow deformation, then the skirt can engage the threads, but the tabs hook the threads during rescrewing making it impossible to unscrew
Solution Approach 1:
The tapered thread profile changes the engagement parameters dynamically during the unscrewing process. As the skirt rotates outward, the varying thread width creates progressive disengagement of the flexible tabs, preventing them from hooking and binding the threads, thus enabling smooth unscrewing operations.
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 configuration creates a clearance between the skirt imprints and the neck threads during rescrewing, making it easier to engage the skirt on the threads without requiring multiple attempts, and provides a justified feeling of sufficiency and quality due to the increasing torque required for rescrewing.
Implementation Method 1
The intermediate portion has a cross-section that decreases in the unscrewing direction and/or increases in the screwing direction, such that the unscrewing torque decreases and/or the rescrewing torque increases
Data Source
AI summary
A fluid product dispenser having a vessel and provided with a neck forming at least one helical thread, and a dispensing head mounted on the neck of the vessel, the head having a dispensing member and a fastening member engaging both with the threaded neck and the dispensing member The fastening member has a deformable and malleable skirt intended to engage with the threaded neck, and a rigid collar engaged around the skirt to push the skirt radially against the threaded neck in such a way as to deform the skirt against the thread so as to create a thread imprint in the skirt. The helical thread has an intermediate portion that has, on at least some of its length, a cross-section that decreases in the unscrewing direction and increases in the screwing direction, such that the unscrewing torque decreases and the rescrewing torque increases.