Injection Dosing Sleeve Locking for Compact Anti-Reverse Drive
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing injection devices are often bulky due to the need for anti-rotation locks that prevent unintentional shifting of the plunger rod, which occupy additional space and complicate the design.
Innovation Solution
A dosing and dispensing mechanism with a coupling sleeve that includes a locking element interacting with a housing insert, allowing for compact design by enabling rotation in one direction and preventing it in the opposite direction without requiring additional space at the ends, and a dosing sleeve that adjusts and corrects doses through threaded engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reverse rotation lock or anti-rotation lock is used to prevent unintentional shifting of the plunger rod, then the reliability of dose dispensing is improved, but the device complexity and length increase
Solution Approach 1:
The locking element is integrated directly into the coupling sleeve, merging the locking function with the existing coupling mechanism. This eliminates the need for separate locking components and reduces overall device complexity while maintaining the anti-rotation function.
Solution Approach 2:
The coupling sleeve serves multiple functions: it couples the dosing sleeve to the drive mechanism during dose dispensing and simultaneously provides the locking function through its integrated locking element. This multi-functionality reduces the number of separate components needed.
2Reliability
If ratchet elements are arranged directly on the housing to prevent piston rod rotation, then the reliability of dose dispensing is improved, but the device length increases
Solution Approach 1:
Instead of arranging locking elements axially at the ends of the device, the locking element is positioned radially on the outer side of the coupling sleeve, interacting with the housing insert in a radial direction. This dimensional change allows the locking function to be achieved without increasing the axial length of the device.
Solution Approach 2:
The locking element is nested within the coupling sleeve structure, with the coupling sleeve itself serving as the housing for the locking mechanism. This nesting approach eliminates the need for additional external locking components that would increase device length.
3Reliability
If additional locking components are added to prevent reverse movement, then the reliability is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The locking element is formed as an integral part of the coupling sleeve, combining two functions (coupling and locking) into a single component. This reduces the number of parts to be manufactured and assembled, thereby improving ease of manufacture while maintaining reliability.
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 allows for a more compact injection device design while ensuring secure dose setting and dispensing without unintentional plunger rod movement, reducing component count and simplifying assembly.
Implementation Method 1
the coupling sleeve may include a locking element for interacting with the housing insert in such a way that the coupling sleeve may be rotated in a first direction of rotation relative to the housing insert and may be prevented from being rotated in a second direction of rotation relative to the housing insert
Implementation Method 2
a dosing sleeve that may be mounted in the housing for adjusting and correcting the dose
Data Source
AI summary
An injection device for dispensing a dose of a product by manually advancing a piston rod includes a dosing and dispensing mechanism having a housing with a longitudinal axis, a dosing sleeve mounted in the housing for adjusting and correcting the dose, a housing insert fixed to the housing and arranged inside the dosing sleeve, and a coupling sleeve mounted in the housing for driving the piston rod. For setting and correcting a dose, the dosing sleeve is rotatable relative to the coupling sleeve, and for dispensing the dose, the dosing sleeve can be coupled to the coupling sleeve in a rotationally fixed manner. In this case, the coupling sleeve has a locking element which can interact with the housing insert so that the coupling sleeve can be rotated in a first direction of rotation and cannot be rotated in a second direction of rotation relative to the housing insert.