Rigid Needle Guard Sharp Angle Assembly
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Solution Overview
Problem
Rigid needle guards with rounded folded-in portions in autoinjectors can prevent reliable removal by the remover member due to sliding issues, leading to ineffective needle protection and assembly challenges.
Innovation Solution
A rigid needle guard design featuring a folded-in portion with a sharp and acute angle (<90°) on the outer surface, formed by a combination of a folder head and a shaper head, ensuring secure cooperation with the remover member and preventing sliding, along with an assembly method and machine for efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bottom axial end of the rigid outer body is folded in with a rounded outer shape to avoid crushing during folding, then the structural integrity is maintained, but the remover member slides over the folded-in portion preventing reliable removal
Solution Approach 1:
The patent applies local quality by creating a specific geometric feature (sharp and acute angle) at the axially-bottom and radially-outer edge of the folded-in portion. This localized angular feature differs from the rounded shape and provides the necessary mechanical engagement for the remover member while maintaining the overall rounded structure for structural integrity.
Solution Approach 2:
The patent changes the geometric parameter of the folded-in portion from a rounded outer shape to one featuring a sharp and acute angle (less than 90 degrees) at the axially-bottom and radially-outer edge. This parameter change enables the folded-in portion to engage with the remover member's shoulder, preventing sliding and ensuring reliable removal.
2Ease of manufacture
If a folder head with a rounded folder cavity is used to fold the bottom axial end, then crushing is avoided, but the resulting rounded shape prevents effective cooperation with the remover member
Solution Approach 1:
The patent applies preliminary action by first forming the folded-in portion with a rounded shape using the folder head to avoid crushing, then subsequently modifying it with a shaper head to create the sharp and acute angle. This two-step preliminary action ensures both ease of manufacture and reliable cooperation with the remover member.
Solution Approach 2:
The patent changes the geometric parameter of the folded-in portion from a rounded outer shape to one featuring a sharp and acute angle (less than 90 degrees) at the axially-bottom and radially-outer edge. This parameter change enables the folded-in portion to engage with the remover member's shoulder, preventing sliding and ensuring reliable removal.
3Device complexity
If the folded-in portion has a rounded outer shape, then the folding process is simple, but axial movement and removal by the remover member are prevented
Solution Approach 1:
The patent applies local quality by creating a specific geometric feature (sharp and acute angle) at the axially-bottom and radially-outer edge of the folded-in portion. This localized angular feature differs from the rounded shape and provides the necessary mechanical engagement for the remover member while maintaining the overall rounded structure for structural integrity.
Solution Approach 2:
The patent changes the geometric parameter of the folded-in portion from a rounded outer shape to one featuring a sharp and acute angle (less than 90 degrees) at the axially-bottom and radially-outer edge. This parameter change enables the folded-in portion to engage with the remover member's shoulder, preventing sliding and ensuring reliable removal.
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 sharp and acute angle on the folded-in portion of the rigid needle guard enables reliable axial movement and removal by the remover member, enhancing protection and simplifying the assembly process while maintaining the structural integrity of the needle guard.
Implementation Method 1
Typically, the folding step is performed hot by means of a folder head 30
Implementation Method 2
The folded-in portion 121, formed during the folding step
Implementation Method 3
The shaper head 40 is adapted to deform the rounded outer surface of the folded-in portion 121 formed by the folder head 30
Implementation Method 4
deforming the rounded outer surface of said folded-in portion so as to form a sharp and acute angle
Data Source
AI summary
An assembly machine for assembling a rigid needle guard (10) having an inner part (11) made of elastomeric material, and a rigid outer body (12) that is fastened to the inner part (11) made of elastomeric material via a folded-in portion (121) of the bottom axial end of the rigid outer body (12). The folded-in portion (121) extends radially inwards from the outer peripheral surface (125) of the rigid outer body (12), the outer surface of the folded-in portion (121) forming, at its axially-bottom and radially-outer edge, a sharp and acute angle relative to the outer peripheral surface (125) of the rigid outer body (12).