Panel Fastener Hook and Cam Assembly with Radial Spring Compression
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Solution Overview
Problem
Existing panel fastener cam and hook assemblies with ob-round cam holes are prone to spring disengagement, making them difficult to reset and requiring manual intervention, and suffer from torque reduction due to tangential spring compression, leading to panel shifting during assembly.
Innovation Solution
A panel fastener design featuring a round cam engagement hole and a C-shaped leaf spring mounted within a spring mounting notch, ensuring the spring remains compressed and providing radial compression for stable torque, eliminating the need for ob-round recesses and reducing torque loss over use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an ob-round cam hole design is used, then the spring can be inserted during assembly, but the cam can be rotated to release the hook and the spring may become dislodged
Solution Approach 1:
The patent inverts the conventional ob-round hole design by using a round cam engagement hole with a separate spring mounting notch. This inversion prevents the cam from rotating to release the hook while maintaining ease of spring insertion during assembly. The spring is positioned in the notch and compressed against the round hole, creating secure engagement without the rotational release problem of ob-round designs.
Solution Approach 2:
The patent segments the cam hole function into two separate features: a round cam engagement hole for torque transmission and a spring mounting notch for spring positioning. This segmentation allows the spring to be easily inserted during assembly while preventing cam rotation that would release the hook, resolving the contradiction between ease of manufacture and reliability.
2Ease of operation
If tangential spring compression is used, then the spring can engage the cam, but torque is reduced leading to panel shifting
Solution Approach 1:
The patent uses asymmetric positioning of the spring mounting notch relative to the round cam engagement hole to create radial compression. The spring is compressed in a direction perpendicular to the cam rotation axis, generating stable torque that prevents panel shifting during assembly operations.
3Duration of action of moving object
If the spring is allowed to decompress, then the spring can return to its original position, but the spring becomes dislodged from the recess
Solution Approach 1:
The patent inverts the retention mechanism by using a round cam engagement hole that continuously engages the spring, preventing dislodgment during the spring's return movement. The spring mounting notch provides initial positioning, but the round hole ensures continuous engagement and retention throughout the spring's compression and decompression cycle.
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 design enhances the security of the spring engagement, prevents dislodgment, and maintains consistent torque, facilitating easier assembly and reducing panel shifting during installation by keeping the spring in a compressed state, thus improving the reliability and efficiency of panel fastening.
Implementation Method 1
contact between the spring and the generally round cam engagement hole causes frictional contact sufficient to rotate the hook through rotation of said cam
Implementation Method 2
a spring mounted within the spring mounting notch of the cam... Upon rotation of the cam within the hook opening and compression of the spring, the spring flexes below the ledges and is not crimped
Data Source
Figure 1~2
Figure 3~4
AI summary
A panel fasteners (20) is disclosed in the form of a hook and cam assembly (21) having two side walls (24) with a boss (27) through which a cam shaft (28) is journalled. The cam shaft has a socket (29) and a round cam (30). A hook (32) is frictionally mounted in camming engagement with the cam. A leaf clutch spring (33) is mounted within a spring mounting notch (36) and in frictional engagement with a substantially round cam engagement hole (34) of the hook. To position the spring into the spring mounting notch and cam engagement hole the spring is pre-compressed prior to mounting it within the spring mounting notch by forcing it through a narrowing channel positioned adjacent the cam.