Threaded Bottle Can Neck Design for Stable Cap Torque
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Solution Overview
Problem
Existing methods for forming threads on bottle-shaped cans often result in reduced thread accuracy due to buckling and deformation of the neck portion, leading to unstable torque for cap rotation and compromised sealing ability.
Innovation Solution
A metallic threaded bottle-shaped can design featuring upper and lower incomplete thread portions with specific angle settings and a manufacturing method that includes curling, threading, and bead forming steps to improve thread accuracy and neck portion circularity, reducing deformation and enhancing sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thread is formed on the neck portion by pressing the neck portion inwardly and outwardly, then the thread is formed on the neck portion, but the thread accuracy is reduced due to buckling or deformation of the neck portion
Solution Approach 1:
A tapered part is formed below the curled portion on the upper end of the neck portion before thread formation, creating a gradual diameter increase from the curled portion. This preliminary structural preparation provides support during subsequent threading operations, preventing buckling and deformation that would otherwise occur when pressing the neck portion inwardly and outwardly to form the thread.
2Reliability
If the thread is formed in such a manner as to situate an incomplete-thread part of a starting end of the thread at an intermediate part of the tapered part, then the thread engagement is improved, but the thread accuracy is still reduced due to deformation
Solution Approach 1:
The thread structure is designed with differentiated regions: a complete-thread part with full thread pitch and depth formed on the cylindrical portion, and an incomplete-thread part with reduced thread depth formed on the tapered part. This local differentiation allows the thread to engage reliably with the cap while the tapered region's gradual geometry minimizes deformation and maintains manufacturing precision during formation.
3Ease of operation
If the cap is twisted counterclockwise to dismount from the neck portion, then the cap is dismounted by the action of the thread ridge and thread groove, but the torque is unstable due to thread deformation
Solution Approach 1:
The tapered part is formed in advance below the curled portion, creating a gradual diameter increase that supports the thread structure during both mounting and dismounting operations. This preliminary structural preparation ensures that the thread ridge and groove maintain their geometric integrity, providing stable torque characteristics when the cap is twisted counterclockwise for dismounting.
4Shape
If the neck portion is drawn and ironed to form a bottle-shape, then the bottle-shape is formed, but the circularity and flatness of the neck portion are compromised during subsequent thread formation
Solution Approach 1:
The tapered part is formed as a preliminary structure below the curled portion before thread formation operations. This pre-formed tapered geometry with gradual diameter increase provides a supportive framework that maintains the neck portion's circularity and flatness during subsequent threading, curling, and bead forming operations, preventing deformation that would compromise manufacturing precision.
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 stabilizes cap rotation torque and improves sealing by minimizing deformation and distortion during thread formation, ensuring the thread engages smoothly with the cap and maintaining the neck portion's circularity and flatness.
Implementation Method 1
an opening end of the neck portion is curled
Implementation Method 2
the thread as a helical ridge is formed on the neck portion by pressing the neck portion inwardly and outwardly
Implementation Method 3
the cap is dismounted from the neck portion by the action of the thread ridge and the thread groove
Data Source
AI summary
A bottle-shaped can in which flatness and circularity of a neck portion are improved. An upper incomplete thread portion is formed at an upper end of a thread. A height of the upper incomplete thread portion is shorter than an average height of the thread, and increases gradually toward the average height. A length of the upper incomplete thread portion between a first point and a second point is set in such a manner that an angle between a line drawn between the first point and a center point of the neck portion, and a line drawn between the second point and the center point of the neck portion falls within a range from 20 degrees to 60 degrees.