End-stop Detection Flag Member Sensor Shaft Assembly
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Solution Overview
Problem
Existing electromechanical surgical devices face challenges in accurately and reliably detecting the end stop of an end effector assembly, which is crucial to prevent damage and ensure proper functioning during surgical procedures.
Innovation Solution
The implementation of a hand-held surgical instrument with a shaft assembly that includes a drive member, a flag member, and a sensor, where the flag member translates axially along the drive member and contacts a sensor to provide a signal indicating the end stop, causing the motor to stop, and a controller manages this process to ensure accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If motor current measurement is used to detect end stop, then the detection method is simple, but the detection reliability is insufficient
Solution Approach 1:
The patent introduces a flag member as an intermediary mechanical element that physically contacts the sensor to indicate end stop position. This mechanical intermediary provides reliable detection by converting the end stop position into a direct physical contact event, eliminating the unreliability of motor current measurements while maintaining system simplicity.
Solution Approach 2:
The patent replaces the electrical measurement method (motor current sensing) with a direct mechanical detection method (flag member contacting sensor). This substitution provides more reliable end stop detection by using direct physical contact rather than indirect electrical measurements, resolving the contradiction between simplicity and reliability.
2Measurement precision
If a flag member with sensor contact is added to detect end stop, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The flag member serves multiple functions: it acts as a detection trigger for the sensor, a mechanical indicator of end stop position, and an integral part of the drive mechanism. By making the flag member multi-functional, the patent improves detection accuracy without proportionally increasing device complexity, as the same component performs multiple roles.
Solution Approach 2:
The patent combines the end stop indication function with the existing drive mechanism by integrating the flag member into the shaft assembly. This merging of functions allows the detection system to utilize existing structural elements, thereby improving measurement precision while minimizing the increase in overall device complexity.
3Reliability
If rapid end stop detection is implemented, then device protection is improved, but detection system complexity increases
Solution Approach 1:
The flag member is pre-positioned along the drive member's path of travel, ready to contact the sensor immediately when the end stop is reached. This preliminary positioning enables rapid detection because no additional sensing or calculation is needed—the mechanical contact occurs automatically at the precise moment the end stop is reached, providing immediate device protection without complex detection 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
This solution enables rapid and accurate detection of the end stop, preventing damage to the surgical device and ensuring reliable operation by stopping the motor when the end stop is reached, allowing for efficient handling of disposable loading units and minimizing tissue trauma.
Implementation Method 1
the sensor may include a highly poled piezo crystal or a stack of highly poled piezo crystals
Data Source
AI summary
The present disclosure is directed to systems and methods for operating an electromechanical surgical system. The electromechanical surgical system includes a hand-held surgical instrument including an instrument housing defining a connecting portion for selectively connecting with a shaft assembly. The system also includes an end effector configured to perform at least one function. The shaft assembly is arranged for selectively interconnecting the end effector and the hand-held surgical instrument. The shaft assembly includes a drive member, a flag member configured to translate axially along the drive member, and a sensor disposed about the drive member. The sensor provides a signal indicating that the end effector has reached an end stop when the flag member contacts that sensor.