Tread Joining Device for Seamless Tire Retreading
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Solution Overview
Problem
Current tire retreading methods result in aesthetically unpleasing joints due to noticeable gaps or oversized tread sections, and are costly when using tread ring molds.
Innovation Solution
A tread joining device and method that forms 'generally matching' terminal ends of tire tread portions, allowing for controlled application and removal of elastomeric joining material to create a seamless, aesthetically pleasing joint without the need for expensive molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If current retreading methods are used to join treads by filling gaps with elastomeric material and stapling ends, then the joining process is simple and low-cost, but the resulting joint is aesthetically unpleasing with noticeable gaps and uneven surfaces
Solution Approach 1:
The joining process is divided into distinct stages: preliminary positioning with staples, controlled compression to expel excess material, and sequential staple removal. This segmentation allows each stage to optimize for its specific function while maintaining overall aesthetic quality.
Solution Approach 2:
Staples are applied in advance to preliminarily secure the tread ends in proper alignment before the actual compression and material expulsion occurs. This preliminary positioning ensures that when excess material is expelled, the joint maintains consistent geometry and aesthetic appearance.
2Ease of manufacture
If splice joint method is used to join treads by placing elastomeric material between tread ends and compressing in a flat mold, then the joining process is straightforward, but excess joining material is molded into the tread creating an oversized portion that varies in size and shape
Solution Approach 1:
The method extracts excess joining material from the joint area through controlled compression, forcing it outward rather than allowing it to be molded into the tread. This extraction prevents the formation of oversized portions and ensures consistent joint dimensions matching the remaining tread portions.
Solution Approach 2:
The compression parameters are carefully controlled to achieve the optimal balance between expelling excess material and maintaining joint geometry. By adjusting compression force and duration, the process ensures excess material is removed while the joint maintains precise size and shape consistency with the rest of the tread.
3Shape
If a tread ring mold is used to form a jointless continuous tread ring, then the cosmetic quality is excellent with no visible joints, but the manufacturing cost becomes very costly
Solution Approach 1:
The method replaces the expensive reusable tread ring mold with disposable staples and a simple flat compression surface. The staples are consumed in the process and removed afterward, eliminating the need for costly specialized molding equipment while achieving comparable cosmetic results.
Solution Approach 2:
The staples are discarded after serving their preliminary positioning function, and excess elastomeric material is removed rather than incorporated into the final product. This discarding approach eliminates the need for expensive molds while maintaining joint quality through selective removal of unnecessary components.
Data Source
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AI summary
The subject invention includes methods and apparatus for joining treads. Such methods include the step of providing a first tread portion and a second tread portion for forming a joined tread, each tread portion comprising a section of tire tread extending lengthwise from a terminal end. Additional steps include providing a first fixture configured to retain the first tread portion and a second fixture configured to retain the second tread portion and securing the first tread portion into the first fixture and securing the second tread portion into the second fixture, each of the first and second fixtures being arranged within the first and second fixtures such that the terminal end of each tread portion is in communication with a joining side of each fixture. The methods further include directing the terminal ends towards each other and into forceful engagement with an elastomeric joining material arranged between the terminal ends.