Torsion Spring Dial-Down Mechanism for Wind-Up Pen
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Solution Overview
Problem
Existing dial-down mechanisms in wind-up pens require users to apply force and adjust the angular position of the dose setting member, making it difficult for individuals with reduced motoric skills or strength, such as children, elderly people, or disabled individuals to correctly set or reset medication doses.
Innovation Solution
A dial-down mechanism that utilizes a torsion spring-assisted system with a dial-up cam and dial-down cam, allowing for radial or axial movement, where a single key can be used for both dial-up and dial-down functions, enabling easier adjustment of medication doses by straining and releasing the torsion spring through distinct rotation directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional dial-down mechanism is used requiring manual force application and angular adjustment, then the mechanism can reset the dose setting, but the operation becomes complex and difficult for users with reduced motoric skills or finger strength
Solution Approach 1:
The torsion spring automatically performs the dose adjustment operation once initiated. The spring's stored energy drives the dose setting member to return to its initial position, eliminating the need for the user to manually apply continuous force or precisely control angular movement during the reset process.
Solution Approach 2:
The mechanism changes the operational parameters by converting manual angular rotation into axial movement through the cam profile. The cam transforms the rotational motion of the dose setting member into linear axial displacement that engages the ratchet teeth, simplifying the user's control requirement from precise angular adjustment to simple rotational initiation.
2Ease of operation
If the user must apply force to withdraw the dose setting member axially and adjust angular position simultaneously, then the dial-down function can be achieved, but the procedure becomes complicated for individuals with reduced motoric skills
Solution Approach 1:
The mechanism segments the dosing operation into distinct phases: dosing (where the spring is wound and stored energy is accumulated) and resetting (where the spring automatically returns the dose setting member to its initial position). This separation allows the user to simply initiate the reset by rotating the dose setting member, while the spring handles the complex axial withdrawal and angular adjustment automatically.
Solution Approach 2:
The torsion spring acts as an intermediary element that mediates between the user's simple rotational input and the complex mechanical requirements of the dose setting member. The spring converts the user's minimal effort into the necessary axial and angular movements through its elastic energy storage and release characteristics.
3Power
If a linear spring is used as in WO 02/053214, then the spring can assist the injection, but the dial-down mechanism still requires user force application for dose adjustment
Solution Approach 1:
The torsion spring is configured to automatically perform the dose adjustment function after being wound during the dosing phase. Once the user initiates the reset by rotating the dose setting member, the spring's stored energy automatically drives the return motion, making the system self-servicing and eliminating the need for continuous user force application during the reset operation.
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 easier and more accessible dose adjustments for users with reduced motor skills by integrating a torsion spring-assisted mechanism that allows for intuitive dial-up and dial-down operations, reducing the complexity of setting or resetting medication doses in wind-up pens.
Implementation Method 1
a torsion spring (35) arranged to strain upon rotation of the dose setting member (30) in a first direction, wherein the torsion spring (35) is adapted to assist injecting a dose of medicament from the injection device (1)
Implementation Method 2
a dial-up cam (46) arranged to receive and engage with a dial-up key (42), wherein the dial-up cam (46) and the dial-up key (42) are adapted to, upon rotation of a dose setting member (30) in a first direction, cooperate to strain the torsion spring (43) of the injection device (1)
Data Source
AI summary
The present invention relates to a dial-down mechanism for an injection device comprising a torsion spring for assisting injection of a dose of medicament from the injection device, the dial-down mechanism comprising dial-up cam arranged to receive and engage with a dial-up key, wherein the dial-up cam and the dial-up key are adapted to, upon rotation of a dose setting member in a first direction, cooperate to strain the torsion spring of the injection device, and a dial-down cam arranged to receive and engage with a dial-down key, wherein the dial-down cam and the dial-down key are adapted to, upon rotation of the dose setting member in a second direction, cooperate to release the torsion spring of the injection device, the second rotation direction being opposite to the first rotation direction.