Needle Block Assemblies for Fastener Dispensing Jam Reduction
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Solution Overview
Problem
Traditional fastener dispensing devices with adjustable needle spacing suffer from random, multi-directional filament distortion, leading to increased jamming likelihood during high-speed dispensing applications.
Innovation Solution
The device limits filament distortion within a single plane by using needle block assemblies that apply pressure to the cross-links of the fastener stock, preventing upward distortion and maintaining a uniform, equidistantly spaced filament pattern, thereby reducing the likelihood of jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If needle spacing is adjusted in traditional fastener dispensing devices, then adaptability to different fastener configurations is improved, but random multi-directional filament distortion occurs leading to increased jamming likelihood
Solution Approach 1:
The needle block assembly incorporates a compliant mechanism that dynamically adapts to different needle spacings while maintaining controlled filament distortion. The assembly moves as a unified structure that can be positioned at multiple spacing configurations, allowing the device to accommodate different fastener types without causing random filament distortion that leads to jamming.
Solution Approach 2:
The needle block assembly serves as an intermediary component between the needle positioning system and the fastener stock. This intermediate structure controls and limits filament distortion to a single plane, preventing the random multi-directional distortion that occurs in traditional devices, thereby reducing jamming while maintaining spacing adjustability.
2Productivity
If high-speed dispensing is implemented, then productivity is improved, but filament distortion increases leading to more frequent jamming
Solution Approach 1:
The needle block assembly is designed as a dynamic, compliant structure that moves with the fastener stock during high-speed dispensing operations. This unified movement prevents differential motion that causes filament distortion, allowing the device to maintain reliable operation at high speeds without the jamming problems associated with traditional rigid positioning systems.
3Device complexity
If traditional feed mechanisms are used, then device complexity is minimized, but filament distortion occurs in multiple directions causing jams
Solution Approach 1:
The needle block assembly merges the needle mounting function with the filament guidance function into a single integrated component. By combining these functions, the device achieves reliable single-plane filament control without adding complex separate guidance mechanisms, thus maintaining simplicity while improving reliability.
Solution Approach 2:
The needle block assembly acts as an intermediary structure that simplifies the feed mechanism while controlling filament distortion. Instead of using complex multi-component guidance systems, this single assembly component provides the necessary control to limit distortion to one plane, reducing overall device complexity while improving filament alignment reliability.
Data Source
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AI summary
A device (111) for dispensing an individual plastic fastener (18) from a supply of fastener stock (11) includes a motor-driven head assembly(147) adapted to receive the supply of fastener stock (11), sever an individual fastener (18) from the supply (11) and in turn eject the severed fastener (18). The head assembly (147) includes a pair of needle block assemblies (167-1, 167-2) that retain corresponding hollow needles (155-1, 155-2), each needle block assembly (167-1, 167-2) being shaped to define a feed channel (175-1, 175-2) that transitions a side rail (13, 15) for the fastener stock (11) into axial alignment behind its corresponding needle (155-1, 155-2). In addition, at least one needle block assembly (167-1, 167-2) includes a rearward shelf (231-1, 231-2) and a forward bowing plate (255). In use, the lowermost cross-links (17) of the fastener stock (11) fittingly align between the shelf (231-1, 231-2) and the bowing plate (255). In this manner, the lowermost cross-links (17) are limited to distort uniformly upward within the single plane defined by the pair of feed channels (175-1, 175-2), thereby optimizing feed reliability of the device.