Drug Infusion Device Bidirectional Piston Mechanism
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Solution Overview
Problem
Existing drug infusion devices cannot perform suction of a drug into the syringe without removing it, requiring manual filling and limiting consecutive infusions, especially for patients with handling difficulties, and lack the reliability and safety needed for automated syringe filling.
Innovation Solution
A compact electromechanical device with a sliding element, such as a ball or roller thrust bearing, that enables both forward and backward push linear motion, allowing for drug suction and reducing friction during the process, ensuring reliable and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the motor is reversed to aspirate drug into the syringe, then the device can perform suction function, but the reliability and safety standards are compromised
Solution Approach 1:
The device is divided into separate aspiration and infusion mechanisms. The aspiration function uses a dedicated aspiration piston that moves independently from the infusion piston, allowing suction operations without reversing the main infusion motor. This segmentation ensures that each function has its own optimized mechanical path, maintaining reliability while adding versatility.
Solution Approach 2:
An intermediary mechanical assembly is introduced between the motor and the piston, including a sliding element (ball or roller thrust bearing) that facilitates bidirectional motion. This intermediary mechanism allows the system to perform both aspiration and infusion without directly reversing the motor, thereby maintaining operational reliability while achieving the desired versatility.
2Device complexity
If manual syringe filling is required, then the device structure can be simplified, but the ease of operation deteriorates for patients with handling difficulties
Solution Approach 1:
The infusion device is designed with multi-functionality to perform both infusion and aspiration operations using the same mechanical assembly. The sliding element and bidirectional motion capability allow the device to automatically fill syringes by aspirating drug into them, eliminating the need for separate manual filling procedures while maintaining a relatively simple overall device structure.
Solution Approach 2:
The device enables self-service operation by automatically aspirating and filling syringes without requiring patient or caregiver intervention. The programmable controller automates the aspiration process, allowing patients with handling difficulties to independently prepare and use syringes, thereby improving ease of operation while keeping the device structure manageable.
3Reliability
If the syringe is removed after each infusion, then the device can perform thorough cleaning, but the productivity decreases due to repeated attachment and removal
Solution Approach 1:
The device enables continuous operation by allowing the syringe to remain attached during aspiration and infusion cycles. The bidirectional piston mechanism and sliding element facilitate seamless transitions between aspiration and infusion modes without requiring syringe removal, maintaining both cleaning effectiveness and high productivity through uninterrupted operation.
4Ease of operation
If a sliding element is added to reduce friction during backward push motion, then the ease of operation improves, but the device complexity increases
Solution Approach 1:
Instead of attempting to reduce friction through complex surface treatments or lubrication systems, the invention inverts the approach by using a sliding element (ball or roller thrust bearing) that converts the problematic sliding friction into rolling friction. This inversion of the friction reduction strategy achieves ease of operation for backward push motion while adding minimal complexity to the mechanical assembly.
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 multiple consecutive infusions without syringe removal, allows patients to self-fill syringes, and meets safety and reliability standards for prolonged use, reducing the need for a caregiver and lowering manufacturing costs.
Implementation Method 1
it includes a sliding element reducing the friction to the sliding of the contacting surfaces when a resistance contrasting such a backward push linear motion is present
Implementation Method 2
said sliding element includes a ball or roller thrust bearing that is reliable and robust
Data Source
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AI summary
A drug infusion device (11), including a casing (13), a ferrule (15) having coupling means (20) for receiving a syringe (25) equipped with a sliding piston (63), and a pusher (17), which is axially movable to make said piston (63) slide in the syringe, said pusher being associated with a sliding rod (19) that is partially received within the casing (13) and projects therefrom through an opening (21) provided in the ferrule (15), said casing (13) housing the driving members causing the axial sliding of the sliding rod (19), said driving members including an electric motor (35) electronically controlled by a programmable electronic controller and programmed to cause the infusion of the drug contained in the syringe fit onto the device, wherein said controller is also programmed to cause the suction of a drug into the syringe fit onto the device.