Composite Rocker Cam Assembly for Stable Rolling Motion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rocker chair cam assemblies suffer from distortion due to repeated load cycles, inconsistent rocking patterns, labor-intensive and imprecise installation, and potential weakening of the wood structure, leading to a time-consuming and labor-intensive fabrication process.
Innovation Solution
A unitary composite cam member with a rigid body, laterally projecting sleeves, and strengthening ribs is designed for improved durability and ease of installation, featuring a polymeric material like glass-filled nylon for consistent performance and reduced assembly time, ensuring precise alignment and secure attachment to longitudinal rails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wooden cam member with arcuate contact surface is used, then the cam assembly can provide rolling engagement with longitudinal rails, but the contact surface distorts over repeated load cycles leading to inconsistent rocking pattern
Solution Approach 1:
The patent applies composite materials by combining a wooden cam member with a metal reinforcement insert embedded within it. The metal insert provides structural stability and resistance to distortion under repeated loading, while the wooden exterior maintains the traditional aesthetic and rolling contact surface. This composite structure resolves the contradiction by preventing shape instability without compromising the rolling engagement function.
Solution Approach 2:
The patent applies local quality by reinforcing only the specific region of the cam member that experiences the most stress and distortion during operation. The metal insert is strategically positioned within the wooden cam member at the contact surface area, providing localized structural support where needed most, while leaving the rest of the wooden structure intact for its intended function and appearance.
2Reliability
If metal upper bracket is welded to cross tubes, then the cam assembly can be securely attached, but the process is time consuming and labor intensive with imprecise lateral positioning
Solution Approach 1:
The patent replaces the welding process with a mechanical attachment system using pre-drilled holes and fasteners. This substitution eliminates the time-consuming and skill-intensive welding operation while providing precise lateral positioning through the predetermined hole locations. The mechanical fastening system maintains secure attachment reliability without the productivity penalties of welding.
Solution Approach 2:
The patent applies preliminary action by pre-drilling and pre-tapping holes in the cam member and cross tubes before final assembly. This preliminary preparation allows for rapid and precise installation using simple fasteners, eliminating the need for time-consuming welding operations during the final assembly process while ensuring accurate lateral positioning.
3Ease of manufacture
If fasteners are used to attach upper bracket and cam member, then the assembly can be easily installed, but the wood near the attachment point is weakened shortening the cam assembly life
Solution Approach 1:
The patent extracts the fastening function from the wooden cam member by incorporating a metal reinforcement insert that contains the attachment holes. This separates the structural support function (performed by the metal insert) from the rolling contact function (performed by the wooden cam member), allowing fasteners to be installed without weakening the wooden structure that is critical for the cam assembly's operational life.
4Ease of manufacture
If adhesives are used to secure upper bracket with cam member, then some fastener problems are avoided, but adhesives are subject to failure over time and precise assembly steps are still required
Solution Approach 1:
The patent merges the advantages of both mechanical fastening and adhesive bonding by using pre-drilled holes for precise positioning and alignment, combined with adhesive application in the same assembly process. The mechanical holes provide immediate structural support and alignment, while the adhesive fills gaps and provides additional bonding strength, creating a more reliable and simpler-to-manufacture assembly than either method alone.
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 unitary composite cam member provides reliable performance, reduces assembly time, and enhances the durability of rocker chair base assemblies by maintaining structural integrity under repeated loading cycles while ensuring precise alignment and secure attachment, resulting in a more efficient and reliable rocking motion.
Implementation Method 1
The cam member has a generally arcuate contact surface for rolling engagement with an upper flat surface of the respective longitudinal rail 40
Data Source
AI summary
A unitary composite cam member is designed for integration into a rocker chair base assembly. In one arrangement, one cam member resides upon each longitudinal rail of the rocker chair base assembly. Each cam member includes a rigid body and one or more laterally projecting sleeves. The rigid body has an upper portion as well as a lower contact surface presenting an arcuate longitudinal profile. The shape of the contact surface enables rolling engagement on a longitudinal rail of a rocker chair base assembly. Each projecting sleeve extends laterally from the rigid body at a location generally near the top of the cam member. The projecting sleeves are designed to provide an attachment point for cross members of a rocker chair base assembly to accomplish coupling together of the cam members with each aligned upon one of the longitudinal rails. Additionally, the projecting sleeves are configured for securing rocker spring assemblies directly therewith to provide improved efficiencies in the fabrication of rocker chair base assemblies.