Die-Cast Zinc Ring for Sonic Toothbrush Assembly
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Solution Overview
Problem
The existing manufacturing process for brush head attachments with metal rings is costly and prone to errors due to the use of stainless steel rings, which require costly turning and erosion, and can result in burrs and tolerance issues.
Innovation Solution
A die-cast zinc metal ring is used, with a flange region and pin section, and a ring surface with a smaller outer diameter, transitioning to a uniform cylindrical inner surface, which is cost-effective and burr-free, and fits directly into the coupling member without geometric deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a stainless steel ring is used and manufactured by turning and eroding, then the metal ring can be produced, but the manufacturing process is costly and time-consuming
Solution Approach 1:
The patent changes the manufacturing method from mechanical turning and eroding to die-casting, fundamentally altering the production parameters. This allows the metal ring to be formed directly in its final shape during casting, eliminating subsequent machining operations and significantly improving both ease of manufacture and productivity
Solution Approach 2:
The die-casting process performs the shaping action in advance during the primary manufacturing step. The metal ring is cast with its final geometry including the pin section and flange region already formed, so no additional machining or shaping operations are needed later in the production process
2Manufacturing precision
If a stainless steel ring is turned and eroded, then the metal ring can be manufactured, but burrs may remain and tolerance limits may be exceeded
Solution Approach 1:
Changing from mechanical removal processes (turning and eroding) to a formative process (die-casting) fundamentally alters how the metal ring is created. The die-casting process forms the ring in its final shape without material removal, eliminating the generation of burrs and ensuring consistent dimensional accuracy within tight tolerances
Solution Approach 2:
The patent converts the potential harm of complex machining operations (which can create burrs and tolerance issues) into a benefit by using die-casting. The casting process naturally produces smooth surfaces and precise geometries without the harmful byproducts of mechanical machining
3Reliability
If a metal ring is introduced into the coupling member, then the oscillation behavior is improved, but accurate insertion and anchoring without tolerance issues is difficult
Solution Approach 1:
The die-casting process creates the metal ring with its final precise geometry including the pin section and flange region in advance. This preliminary formation ensures that the ring fits accurately into the coupling member's recess without requiring additional tolerance compensation or complex assembly procedures
Solution Approach 2:
The patent changes the manufacturing approach to die-casting, which provides superior dimensional control and surface finish compared to mechanical machining. This results in a metal ring that can be accurately inserted and anchored in the coupling member with consistent tolerance adherence
4Ease of manufacture
If a die-cast zinc metal ring is used, then production costs are reduced and burrs are eliminated, but the mass must be maintained to ensure proper oscillation transfer
Solution Approach 1:
The patent changes the material from stainless steel to die-cast zinc and modifies the geometric parameters (adding a flange region and pin section) to achieve the required mass. The die-casting process allows precise control of material volume and distribution, ensuring the zinc ring has the appropriate weight for oscillation transfer while being more cost-effective than stainless steel
Solution Approach 2:
The patent uses a composite approach by combining die-cast zinc material with a specifically designed geometry (flange region and pin section). This combination allows the lighter zinc material to achieve the required functional mass and structural integrity that would be more expensive to obtain with stainless steel
Data Source
AI summary
The present invention relates to a brush head attachment, in particular for an electric sonic toothbrush, comprising a shank member carrying a bristle bundle, and a coupling member (1) provided on the fastening-side end of said shank member with at least one connection surface for a drive shaft of said handpiece which, when a brush head attachment is mounted on a handpiece, protrudes into said coupling member (1), a spring element that can be operatively connected with said drive shaft for securing said drive shaft to said brush head attachment and/or transferring a drive motion of said drive shaft to said brush head attachment, and a metal ring (4) disposed in a widened fastening foot (2) formed by said coupling member (1). In this inexpensively manufactured brush head attachment according to the present invention, said metal ring (4) is a die-cast member.