Spring-Locked Assembly Nest for Precise Pen Injector Alignment
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Solution Overview
Problem
Existing assembly nests for drug delivery devices on automated production lines fail to securely and efficiently orient and retain sub-assemblies, particularly tubular components, during the assembly process, leading to potential misalignment and assembly errors.
Innovation Solution
An assembly nest with a locking mechanism featuring a resilient coil spring and obliquely positioned locking pins that move between locked and unlocked positions to securely hold and release tubular sub-assemblies, ensuring precise orientation and positioning on an automated assembly line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to the assembly nest to securely retain sub-assemblies, then the reliability of the assembly process is improved, but the device complexity increases
Solution Approach 1:
The locking mechanism is designed to automatically engage and disengage without requiring external actuation. The resilient member (spring) automatically urges the locking pin into engagement with the sub-assembly, and the oblique movement path allows automatic disengagement when the sub-assembly is inserted or removed, making the system self-regulating and eliminating the need for additional actuators or controls
Solution Approach 2:
The patent replaces complex mechanical locking systems with a simple resilient member (spring) that provides automatic locking through elastic deformation. The spring-loaded pin uses the natural elasticity of the resilient material to engage and disengage, substituting what would traditionally require motors, solenoids, or complex cam mechanisms with a passive elastic element
2Ease of operation
If the locking mechanism uses a resilient member to automatically engage and disengage, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The resilient member automatically performs the locking and unlocking functions based on the presence or absence of the sub-assembly, eliminating the need for manual operation or external control systems. The spring-loaded pin self-adjusts its position based on the mechanical interaction with the sub-assembly geometry
Solution Approach 2:
The locking mechanism transitions from a static fixed-position pin to a dynamic resilient pin that can move between locked and unlocked positions. The oblique movement path allows the pin to dynamically adjust its engagement depth based on the sub-assembly insertion, providing adaptive locking rather than rigid fixed-position locking
3Manufacturing precision
If the locking pin is positioned obliquely to the wall, then the manufacturing precision of sub-assembly orientation is improved, but the device complexity increases
Solution Approach 1:
The locking pin is positioned obliquely rather than perpendicular to the wall, creating an asymmetric geometry that provides superior orientation control. This asymmetric angular positioning allows the pin to simultaneously constrain both axial and non-axial movements of the sub-assembly, providing precise orientation that symmetric perpendicular positioning cannot achieve
Solution Approach 2:
The oblique positioning of the locking pin introduces a dimensional advantage by utilizing angular orientation rather than simple radial positioning. This allows the single pin to control movement in multiple directions simultaneously through its angled geometry, effectively adding orientational control capability without adding more pins
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 assembly nest effectively secures tubular sub-assemblies in an upright position, preventing axial and non-axial movement, thereby ensuring accurate alignment and stable transport during automated assembly processes, reducing the risk of misalignment and assembly errors.
Implementation Method 1
the resilient member is a coil spring arranged about the pin and arranged to urge the gripping end against a sub assembly mounted to the base
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The present invention relates to an assembly nest for transporting a tubular sub assembly of a drug delivery device on an automated production line, wherein the tubular sub assembly comprises a tubular body and a cap that is wider than the tubular body. The assembly nest comprises a base against which a sub assembly of a drug delivery device is mountable to orientate said sub assembly in a predetermined position; and a locking mechanism having a resilient member to urge the locking mechanism into one of: an unlocked position, in which a sub assembly of a drug delivery device can be mounted to the base; or a locked position, in which the locking mechanism engages a mounted sub assembly to retain it in its predetermined position on the base.