Center Deck Assembly Scissor-Lever Mechanism for Tire Building Drum
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tire building drums face challenges in achieving a high crown diameter to minimize ply distortion and optimize tire uniformity, as they struggle to radially expand to the necessary height while also contracting to a compact diameter, requiring increased expansion forces.
Innovation Solution
A center deck assembly with a scissor-lever mechanism and linkages connected to segment bars, which allows for the expansion of the center deck to a high crown diameter of up to 57 mm by using a hub secured to a central drive shaft and pistons connected through linkages, providing mechanical advantage and efficient fluid flow for expansion and contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the tire building drum is designed to radially expand to a high crown diameter to minimize ply distortion, then tire uniformity is optimized, but the required expansion force increases significantly
Solution Approach 1:
The center deck assembly employs a scissor-lever mechanism that transforms the expansion motion into a mechanically advantageous configuration. As the segment bars pivot and extend radially outward, the mechanism dynamically adjusts the force application points, maintaining lower actuation forces while achieving the required 57mm crown diameter for optimal tire uniformity
Solution Approach 2:
The scissor-lever mechanism acts as an intermediary between the hydraulic actuators and the center deck expansion. This intermediate mechanical system amplifies the actuation force and controls the expansion motion, reducing the direct force requirements on the hydraulic system while achieving the necessary crown height for precise tire manufacturing
2Ease of operation
If the tire building drum is designed to radially contract to a compact diameter for component application, then ease of operation is improved, but the ability to achieve high crown diameter is compromised
Solution Approach 1:
The center deck assembly uses a dynamic scissor-lever mechanism that can rapidly transition between extended and retracted configurations. This dynamic capability allows the system to achieve full crown diameter (57mm) for component application, then quickly contract to a compact state for the next tire building cycle, maintaining both operational ease and maximum expansion capability
Solution Approach 2:
The center deck assembly operates in periodic cycles of expansion and contraction. During each cycle, the scissor-lever mechanism extends to provide the full crown diameter for component application, then retracts to a compact state, enabling repeated operation while maintaining both the extended length capability and the ease of operation for component placement
3Manufacturing precision
If a larger crown is provided to minimize distortion during tire building, then manufacturing precision is improved, but the device complexity increases due to the need for high expansion force capability
Solution Approach 1:
The scissor-lever mechanism serves as a mechanical intermediary that provides force multiplication and motion control. This intermediate system enables the achievement of 57mm crown diameter for minimal distortion while avoiding the need for an overly complex high-force hydraulic system, as the mechanical advantage of the scissor-lever reduces the required actuation forces
Solution Approach 2:
The invention replaces a direct high-force mechanical expansion system with a scissor-lever mechanism that uses mechanical advantage to achieve the same expansion effect with lower forces. This substitution reduces the complexity of the overall drum mechanism while maintaining the capability to achieve the required crown diameter for precise tire manufacturing
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention is directed to a center deck assembly (100) for a tire building drum. The tire building drum is rotatably mounted on a central drive shaft and includes a center section (110) . The center deck assembly is disposed in the center section of the drum and includes a hub (112) that seats on and is secured to the central drive shaft. At least one piston (124, 126) extends circumferentially in the tire building drum about the hub and a plurality of segment bars (186) are disposed about the circumference of the center deck assembly. The at least one piston (124, 126) is operably connected to the segment bars by a plurality of linkages (154) , in which each of the linkages (154) includes a scissor-lever mechanism.