Cam-Driven Micro-Volume Injection Device for Ophthalmic Precision
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Solution Overview
Problem
Ophthalmic surgery requires precise injection and aspiration of fluids, but conventional syringes lack accuracy due to uncontrolled flow rates, parallax errors, and difficulty in positioning, leading to tissue damage and imprecise material delivery.
Innovation Solution
A device with a cam mechanism and lead screw system that allows for precise control of fluid delivery and aspiration through oscillation of an engaging member relative to a cam device, enabling controlled rotation and longitudinal movement of a plunger to manage fluid volumes and flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional syringe and needle are used for manual injection, then the device is simple and easy to operate, but the injection precision and flow rate control are poor leading to tissue damage
Solution Approach 1:
The patent replaces the manual mechanical syringe system with an automated micro-pump system that uses a cam mechanism and lead screw to precisely control plunger movement. This substitution enables precise control of injection volume and flow rate while eliminating the imprecision and tissue damage associated with manual syringe operation
Solution Approach 2:
The patent changes the control parameters from manual force application to mechanically controlled displacement. The cam mechanism converts rotational motion into precise linear displacement of the plunger, allowing control of injection parameters (volume, flow rate, timing) that were previously uncontrollable with manual syringes
2Speed
If manual syringe operation is used, then the device is simple, but the flow rate control is difficult since it depends on operator force
Solution Approach 1:
The patent replaces manual force-based flow control with a mechanical system where the cam mechanism and lead screw convert rotational motion into controlled linear motion of the plunger. This provides precise flow rate control independent of operator force, while the oscillating cam mechanism maintains operational simplicity through intuitive back-and-forth actuation
3Measurement precision
If a conventional syringe is used, then the device is simple, but the volume control accuracy is reduced due to parallax error and small scale readings
Solution Approach 1:
The patent eliminates parallax error by replacing manual scale reading with a mechanical transmission system. The cam mechanism and lead screw provide direct mechanical coupling between actuator motion and plunger displacement, making volume control dependent on precise mechanical geometry rather than visual scale interpretation, thereby eliminating parallax errors
Solution Approach 2:
The patent introduces the lead screw as an intermediary between the cam mechanism and the plunger. This intermediary component translates the oscillating cam motion into unidirectional rotational motion that precisely controls plunger displacement, providing accurate volume control that is mechanically determined rather than visually estimated
4Measurement precision
If manual syringe injection is used, then the device is simple, but the ability to control injection timing and stop at desired amounts is limited
Solution Approach 1:
The patent replaces manual timing control with a mechanical system where the oscillating cam mechanism provides inherent timing control. The cam geometry determines the duration and rate of plunger movement, enabling precise control of injection timing and automatic stopping at predetermined volumes without requiring operator intervention or complex control 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
The device provides precise control over fluid volumes and flow rates, reducing tissue damage and improving accuracy in ophthalmic procedures by allowing for precise injection and aspiration of materials, such as anticoagulants and therapeutic drugs, into the eye.
Implementation Method 1
a cam device coupled to the lead screw and having a plurality of cams, at least one engaging member adapted to engage the plurality of cams... The actuator may be operable to oscillate the at least one engaging member to alternately engage the plurality of cams so as to rotate the cam device in a single direction
Implementation Method 2
The lead screw may include a first portion coupled to the structure and a longitudinal axis... displacing the lead screw longitudinally relative to the cam device as the cam device is rotated in the first direction
Data Source
AI summary
Micro-volume devices, systems, and associated methods that facilitate the injection or aspiration of precisely controlled volumes of materials at precisely controlled rates are provided. In one embodiment, a micro-volume device includes a syringe and a lead screw connected to a plunger of the syringe. A mechanical interface is connected to the lead screw and includes a first set of cams adjacent a proximal portion and a second set of cams adjacent a distal portion. A mechanism is configured to oscillate a structure in a direction parallel to a longitudinal axis of the lead screw such that one or more projections of the structure to alternatively engage cams of the first and second sets of cams in a manner that results in rotation of the mechanical interface in a single direction for highly controlled linear displacement of the plunger.