Injector Cover Removal Assembly With Floating Lost Motion
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Solution Overview
Problem
Existing injectors face challenges in reliably removing the syringe cover due to manufacturing tolerances and variations in axial positioning, which can lead to integrity issues and reduced reliability, especially when accidentally dropped.
Innovation Solution
The injector features a cover removal assembly with an axially floating lost motion engagement between the outer and inner portions, accommodating variations in axial positioning and manufacturing tolerances, ensuring reliable cover removal and protecting the syringe integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed rigid engagement is used between the cover removal assembly and syringe, then the structure is simple and manufacturing is easy, but manufacturing tolerances and axial positioning variations cause unreliable cover removal and potential syringe damage
Solution Approach 1:
The patent applies parameter changes by introducing a compliant element that changes the mechanical engagement from rigid to flexible, allowing axial movement and rotation to be absorbed without compromising cover removal reliability. This compliant element modifies the engagement parameters to accommodate manufacturing tolerances and positioning variations.
Solution Approach 2:
The compliant element acts as a cushioning mechanism that anticipates and absorbs axial movement and rotation before they can cause damage to the syringe or fail to remove the cover. This beforehand cushioning protects the system from the harmful effects of positioning variations and accidental drops.
2Strength
If the cover removal assembly is directly connected to the syringe, then the structure is simple, but accidental drops transmit impact to the syringe compromising its integrity
Solution Approach 1:
The compliant element serves as a protective cushion that absorbs impact forces from accidental drops before they reach the syringe. This beforehand cushioning prevents damage to the syringe while adding minimal structural complexity to the overall assembly.
Solution Approach 2:
The compliant element acts as an intermediary between the cover removal assembly and the syringe, mediating the transmission of forces. It allows the assembly to be connected to the syringe while protecting the syringe from harmful impacts and forces.
3Reliability
If tight tolerances are enforced for axial positioning, then cover removal reliability improves, but manufacturing cost and complexity increase
Solution Approach 1:
The patent changes the engagement parameters from rigid to compliant, allowing the system to accommodate a wider range of axial positioning tolerances while maintaining consistent and reliable cover removal. This eliminates the need for tight manufacturing tolerances.
Solution Approach 2:
The use of a compliant element introduces a material with different mechanical properties (flexibility and elasticity) into the engagement mechanism. This composite approach combines the rigidity needed for force transmission with the flexibility needed to accommodate positioning variations.
Data Source
AI summary
An injector including a syringe arranged along a longitudinal axis, a removable cover for removable engagement with the syringe and a cover removal assembly including an outer portion which is engagable by a user and is movable axially in a cover disengagement direction along an axial travel path with respect to the longitudinal axis and an inner portion which includes at least one engagement portion which is engagable with the removable cover, whereby axial movement of the inner portion in the cover disengagement direction removes the removable cover from the syringe, at least one of the outer portion and the inner portion being configured such as to provide an axially floating lost motion engagement between the outer portion and the inner portion.