Folding Arm Chevron Support Tyre Sidewall Band
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Solution Overview
Problem
The existing drum apparatuses for building tires face issues with the soft rubber sidewall bands and carcass plies folding irregularly due to unwanted contact with the arms mechanism, leading to defective products.
Innovation Solution
The design of an arm mechanism with a rod and folding assembly featuring a chevron-like support and inclined head portion minimizes contact with the rubber by ensuring the edge of the sidewall band cannot touch the arm or rollers, using a conical head portion with a specific tapering angle and anti-stick coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sidewall band is made of soft rubbery material to facilitate adhesion to the sidewall, then adhesion capability is improved, but the band folds irregularly and adheres to the arms mechanism causing positioning irregularities
Solution Approach 1:
The harmful contact between the arm and the rubber band is eliminated by extracting the arm from the critical positioning zone. The arm is designed with a specific geometry where the head portion is positioned above the equatorial plane, creating a clearance that prevents the soft rubber band from contacting the arm during the positioning operation.
Solution Approach 2:
The folding assembly acts as an intermediary mechanism between the arm and the rubber band. It provides a controlled folding action through rollers that guide the band without causing unwanted adhesion or irregular folding, mediating the interaction between the rigid arm and the soft rubber material.
2Manufacturing precision
If the arm mechanism contacts the rubber band during positioning, then positioning control is improved, but unwanted folding and adhesion occur leading to defective products
Solution Approach 1:
The harmful contact between the arm and the rubber band is eliminated by extracting the arm from the critical positioning zone. The arm is designed with a specific geometry where the head portion is positioned above the equatorial plane, creating a clearance that prevents the soft rubber band from contacting the arm during the positioning operation.
Solution Approach 2:
The folding assembly with rollers provides self-contained controlled folding action without requiring direct arm contact with the rubber band. The rollers guide and fold the band through their own mechanical action, making the system self-sufficient for the folding task while avoiding the adhesion problems associated with arm contact.
3Ease of manufacture
If the arm is designed with a simple structure for ease of manufacture, then manufacturing cost is reduced, but contact with the rubber band cannot be minimized
Solution Approach 1:
The arm is segmented into distinct functional portions: a main body for structural support and a head portion with specific geometric features for positioning. The folding assembly is segmented into multiple rollers that work together. This segmentation allows each component to be optimized for its specific function while maintaining overall manufacturability.
Solution Approach 2:
The problem of contact minimization is solved by moving the arm's critical surfaces to a different spatial dimension - specifically, positioning the head portion above the equatorial plane of the drum. This dimensional relocation creates natural clearance without complicating the arm's basic structure.
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 effectively prevents unwanted folding and adhesion, reducing the likelihood of defective products by ensuring precise positioning of tire components during assembly.
Implementation Method 1
anti-stick coating
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
The present invention relates to a folding arm (10) for a sidewall band of a tyre comprising a rod (11) that has a main portion (15) and a head portion (16) fitted together at an interface section (17). The folding arm further comprises a folding assembly (20) comprising a support (21) and more than one folding roller (22,23) idle mounted on said support, wherein the support (21) has a chevron-like shape and the assembly being connected to an head end (14) of said rod (11). The section area at the head end (14) is lower or equal to 90 % of the area of the interface section (17). The invention also relates to an arm mechanism comprising a plurality of said folding arms and to a drum apparatus for building tyres, comprising one or more of said arms mechanisms.