Knife Handle End Cap Attachment via Ultrasound Plasticization
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Solution Overview
Problem
Existing methods for attaching a metal end cap to a knife handle are labor-intensive, complex, and prone to misalignment, making them difficult to assemble and manufacture efficiently.
Innovation Solution
A plastic handle with a cylindrical opening and an integrally formed peg on the metal end cap, featuring lateral projections and a transverse slot, ensures a secure, form-fitting attachment, with optional ultrasound-induced plasticization for enhanced retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the end cap is forged out on the tang or cast and welded, then the attachment is secure, but the manufacturing process becomes labor intensive and complex
Solution Approach 1:
The end cap is divided into two functional parts: a plastic integration part that forms the handle portion and an metal cap portion that provides the secure attachment. This segmentation allows each part to be optimized for its specific function while simplifying the overall manufacturing process through injection molding
Solution Approach 2:
The metal tang is nested within the plastic handle material during injection molding, with the tang being surrounded and secured by the plastic. The end cap then covers this nested structure, creating a layered secure attachment without requiring separate forging or welding operations
2Reliability
If traditional attachment methods are used, then the end cap can be secured, but misalignment occurs leading to production exclusions
Solution Approach 1:
The tang is positioned and secured within the plastic handle during the injection molding process itself, before the end cap is attached. This preliminary positioning ensures precise alignment is built into the structure during molding, eliminating subsequent alignment issues when the end cap is installed
Solution Approach 2:
The plastic handle structure itself provides the alignment and positioning features for the tang and end cap through its molded geometry. The handle structure serves its own alignment function without requiring separate alignment fixtures or complex assembly procedures
3Ease of operation
If a sleeve with internal thread is used, then the end cap can be attached, but the construction becomes complex to manufacture and assemble
Solution Approach 1:
The functions of the handle end, the attachment mechanism, and the end cap are merged into a single integrated structure. The plastic handle is molded with the tang recess and the end cap is directly attached to cover it, combining multiple components into one secure assembly without requiring separate sleeves, threads, or multiple fastening elements
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 provides a simple, secure, and reproducible attachment method that prevents misalignment, allowing for rapid assembly and processing, while ensuring a tight and moisture-resistant seal.
Implementation Method 1
the end cap is excited by ultrasound when it is inserted into the opening and thereby plasticizes the plastic of the handle
Implementation Method 2
plasticizes the plastic of the handle. What is achieved here is that the plastic of the opening wall, excited by the ultrasound, flows into the spaces between the projections of the pin
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a knife with a metal blade and a tang (2) formed on the blade, which as a flat iron supports the handle (1) made of plastic, wherein a metal end cap (6) is attached to the end of the handle, wherein the plastic at the end of the handle has an opening (4) which leads to the end of the tang, that the metal end cap has a formed pin (5) which fits into the opening in a form-fitting manner, and that the pin has a recess (7) in particular a transverse slot at its end facing the end of the tang, with which it engages the end of the tang in a form-fitting manner.