Rotatable Guide Sleeve Spring Secured Injection Dosing
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Solution Overview
Problem
Existing dose setting devices for injection devices do not allow for easy correction or adjustment of set doses, particularly when a dose is set too high, which can lead to inefficiencies and potential errors in dispensing substances.
Innovation Solution
A dose setting device with a rotatable dosing element and a guiding element that moves or rotates in unison to adjust the selected dose, allowing for correction by reversing the rotation direction, and a spring tensioning mechanism to prevent overloading and ensure safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the dosing element is made rotatable to allow dose adjustment, then the ease of operation is improved, but the device complexity increases due to additional guiding elements and constraints
Solution Approach 1:
The guide element combines multiple functions: it guides the threaded rod axially, prevents rotation of the rod during dosing, and enables rotation during dose correction. By merging these functions into a single component rather than using separate elements, the device achieves dose adjustability without proportionally increasing complexity
Solution Approach 2:
The guide element's rotational constraint is dynamic rather than static. It prevents rotation during normal dosing operation but allows rotation when correcting an overdose. This dynamic behavior is achieved through the interaction between the guide element's geometry and the threaded rod, enabling the system to adapt its constraints based on operational needs
2Reliability
If the spring is secured to the guide element to prevent over-tensioning, then the reliability is improved, but the ease of manufacture worsens due to additional securing features
Solution Approach 1:
The spring securing mechanism is self-regulating. The guide element's geometry automatically limits spring tension by preventing rotation beyond a certain point, eliminating the need for external overload protection devices. The structure serves its primary guiding function while simultaneously providing its own protection against spring damage
Solution Approach 2:
The guide element features asymmetric geometry with a flat side or chamfer that creates a mechanical stop. This asymmetric design allows free rotation in the dosing direction while blocking rotation in the opposite direction, thereby limiting spring tension without requiring complex securing mechanisms or additional parts
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
Enables easy adjustment of set doses without the need for disengagement of components, simplifying the device design and preventing spring overload, thus ensuring accurate and safe dispensing of measured doses.
Implementation Method 1
a spring element (7) which is connected to the guide element (5) and to a plunger rod (4) so as to tense when the dose setting element (1) is rotated
Data Source
AI summary
A dosing device for an injection device, including a dosing element moveable or rotatable in a first direction to select a dose and a guiding element for guiding a component of the injection device, the dosing element being moved or rotated relative to the guiding element to select the dose, wherein the guiding element is rotated or moved along with the dosing element when the dosing element is moved or rotated against the first direction to adjust the selected dose. A method of adjusting a dose selected by a dosing device is encompassed, the method including selecting the dose by moving or rotating a dosing element relative to a guiding element which is moved or rotated along with the dosing element during the selecting and adjusting the selected dose by moving or rotating the dosing element in an opposite direction.