Restricted-Rotation Rod Lock for Stable Drug Injection
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Solution Overview
Problem
Existing autoinjectors require specialized skills for use and lack user-friendly features for dose delivery indication and safe removal after injection, leading to increased manufacturing and assembly costs and environmental impact.
Innovation Solution
A drug injection control device with a rod lock that allows only linear motion under restricted rotation within a rod holder, utilizing a torsion spring mechanism to set and deliver drug doses through a dose dial, ensuring stable drug injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rod lock is allowed to rotate freely within a rod holder while screw-coupled to a piston rod, then the mechanism can accommodate rotational movement, but the drug injection stability deteriorates due to uncontrolled rotation
Solution Approach 1:
The rod lock is designed with dynamic characteristics that allow it to rotate during the injection process. The lock guide includes a guide groove with a specific shape that permits controlled rotation of the rod lock relative to the rod holder, while the screw coupling between the rod lock and piston rod maintains mechanical engagement throughout the motion sequence.
Solution Approach 2:
The mechanism transitions from purely linear motion to combined linear and rotational motion. The guide groove in the rod holder constrains the rod lock to move along a specific three-dimensional path that includes both linear displacement and rotational components, effectively adding a rotational dimension to the otherwise linear injection mechanism.
2Reliability
If the rod lock is constrained to linear motion only, then injection stability is improved, but the mechanism loses adaptability to handle rotational movements
Solution Approach 1:
The rod lock is designed with dynamic characteristics that allow it to rotate during the injection process. The lock guide includes a guide groove with a specific shape that permits controlled rotation of the rod lock relative to the rod holder, while the screw coupling between the rod lock and piston rod maintains mechanical engagement throughout the motion sequence.
Solution Approach 2:
The mechanism transitions from purely linear motion to combined linear and rotational motion. The guide groove in the rod holder constrains the rod lock to move along a specific three-dimensional path that includes both linear displacement and rotational components, effectively adding a rotational dimension to the otherwise linear injection mechanism.
3Ease of operation
If complex indication systems are added to show dose delivery status and safe removal indicators, then user-friendliness is improved, but manufacturing and assembly costs increase
Solution Approach 1:
The device uses color changes as visual indicators to communicate injection status and safe removal conditions to users. Different colors indicate different states of the injection process, providing intuitive feedback without requiring complex electronic displays or additional mechanical indication systems.
Solution Approach 2:
The indication system is designed to automatically provide status information through the mechanical operation of the device itself. The structure and operation of the injection mechanism inherently provide visual or tactile cues about the injection progress and completion, eliminating the need for separate complex indication systems.
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
Facilitates user-friendly drug delivery with reduced manufacturing costs and environmental impact by allowing easy dose setting and safe removal, enhancing user experience and operational simplicity.
Implementation Method 1
an injection amount setting module 100 to set an amount of the drug to be injected by storing a twisting moment in a torsion spring 140 positioned in the housing 10
Implementation Method 2
a rod lock 240 screw-coupled to an outer surface of the piston rod 220 in the rod holder 230
Data Source
AI summary
A drug injection control device has a structure in which a rod lock screw-coupled to a piston rod can make a linear motion under restricted rotation within a rod holder with the rotation of a rod guide and the sub-linear motion of the piston rod. When the injection amount of drug is preset through an injection amount setting module to make a rotational motion with a dose dial in a housing to set the amount of drug to be injected by storing the twisting moment in a torsion spring, in actuating a drug delivery module switchably coupled to the injection amount setting module, the rod lock can make a linear motion by the sliding motion of a lock protrusion through a lock guide formed through the rod holder along the lengthwise direction on the rotation of the rod guide and the sub-linear motion of the piston rod.