Injector Pen Dose Adjustment Mechanism for Reliable Ball Reset
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Solution Overview
Problem
Conventional injector pens face issues with unreliable dose adjustment mechanisms due to the inability of the ball to reset smoothly after kinetic energy release, and they have numerous components that compromise reliability.
Innovation Solution
The dose adjustment mechanism incorporates a power rod, cylinder, ball, sleeve, and torsion spring, allowing the ball to roll smoothly within a spiral channel, with a torsion spring storing energy for reliable dose adjustment and injection, ensuring the ball resets reliably during energy release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional dose adjustment mechanism with many components is used, then the injection dose can be adjusted, but the ball cannot reset smoothly after kinetic energy release and reliability is reduced
Solution Approach 1:
The patent combines the ball, spiral channel, and reset mechanism into an integrated dose adjustment system. The ball rolls within the spiral channel formed by the cylinder and power rod, eliminating the need for separate reset components. This merging of functions reduces component count while ensuring reliable ball reset after kinetic energy release, directly resolving the contradiction between reliability and device complexity.
2Measurement precision
If a conventional dose adjustment mechanism is used, then dose adjustment is possible, but transmission accuracy and ball rolling smoothness are insufficient
Solution Approach 1:
The patent employs a ball with a spherical shape that rolls within a spiral channel. The curved geometry of the ball and the spiral channel work together to ensure smooth rolling motion during dose adjustment. This spherical design maintains high transmission accuracy while enabling effortless operation, as the ball naturally follows the spiral path without binding or sticking, resolving the contradiction between measurement precision and ease of operation.
3Measurement precision
If the ball screw principle is adopted for precise control, then dose control precision is improved, but the mechanism becomes complex with many components
Solution Approach 1:
The patent extracts the essential function of the ball screw mechanism (converting rotational motion to linear motion for precise dose control) while removing unnecessary components. The spiral channel integrated into the cylinder and power rod provides the screw-like motion without requiring separate nuts, bearings, or complex locking mechanisms. This extraction approach maintains precise drug injection control while significantly reducing mechanism complexity.
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 mechanism ensures high transmission accuracy and reliability of dose adjustment, with the ball rolling smoothly and resetting effectively, enhancing the safety and precision of the injector pen's operation.
Implementation Method 1
an upper end of the torsion spring is relatively fixed to the upper pen holder, and a lower end of the torsion spring is connected to the sleeve
Implementation Method 2
the ball screw principle. However, in the conventional dose adjustment mechanism, the ball may not be reset in the process of releasing kinetic energy
Data Source
AI summary
A dose adjustment mechanism includes a power rod, a cylinder, a ball, a sleeve and a torsion spring; the cylinder is outer-mounted on the power rod, a spiral channel extending along the axial direction of the power rod is formed between the inner wall of the cylinder and the outer wall of the power rod, and the ball is rollable in the spiral channel; the cylinder and the upper pen holder of the injector pen are relatively fixed in the circumferential direction; the upper end of the torsion spring is relatively fixed to the upper pen holder, and the lower end is connected to the sleeve; the power rod rotates relative to the cylinder under the action of an external force; the sleeve is limitedly connected to the power rod in a circumferential direction, and the sleeve is configured for transmission cooperation with the transmission mechanism of the injector pen.