Detachable End Effector With Detent Mating Mechanism

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Solution Overview

Problem

Current minimally invasive surgical devices lack a reliable and efficient mechanism for in vivo attachment and detachment of end effectors to elongate shafts, which is crucial for maintaining pneumoperitoneum and facilitating surgical procedures without fluid leakage.

Innovation Solution

A surgical device with an elongate shaft and inner rod, featuring a detent mating mechanism with varying disengagement forces and a sloped surface for lateral spreading of prongs to disengage teeth, allowing for secure attachment and detachment of surgical jaws, enabling efficient tissue manipulation during minimally invasive procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a detent mating mechanism is used to attach the end effector to the elongate shaft, then secure attachment is achieved, but the complexity of the device increases

Engineering Contradiction:
Improvesecure attachmentVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detent mating mechanism is divided into separate components: detents on the outer tube, corresponding notches on the inner rod, and a spring-loaded engagement system. This segmentation allows each component to be simple while collectively providing secure attachment, reducing overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring-loaded detent mechanism automatically engages with the notches when the end effector is inserted onto the elongate shaft, and automatically disengages when withdrawal force is applied. This self-service mechanism eliminates the need for manual operation or complex control systems, achieving secure attachment without increasing device complexity.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If the end effector is designed for in vivo attachment and detachment, then versatility is improved, but the reliability of maintaining pneumoperitoneum may worsen due to potential fluid leakage

Engineering Contradiction:
Improvein vivo attachment and detachmentVSAvoidmaintaining pneumoperitoneum
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The detent mating features are pre-configured with precise geometric relationships between the detents, notches, and spring-loaded engagement surfaces. This preliminary design ensures that when the end effector is attached or detached, the seal maintains continuous contact with the elongate shaft, preventing fluid leakage and maintaining pneumoperitoneum throughout the attachment/detachment process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spring-loaded detent mechanism provides a compliant engagement that accommodates slight misalignments or movements during in vivo attachment and detachment. This beforehand cushioning through spring compliance ensures the seal remains engaged and prevents fluid leakage, maintaining pneumoperitoneum reliability even during versatile attachment operations.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If varying disengagement forces are designed for different mating features, then ease of operation is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvevarying disengagement forcesVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

Different detent mating features are designed with locally optimized properties: the first detent mating feature has a spring constant and engagement geometry optimized for a specific disengagement force, while the second detent mating feature has different parameters for a different disengagement force. This local quality approach allows varying disengagement forces for different operational needs while using standard manufacturing tolerances for each localized feature.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The disengagement forces are varied by changing physical parameters of the detent mechanisms, such as spring constants, detent engagement angles, and contact surface areas. These parameter changes are achieved through standard manufacturing variations rather than requiring extreme precision, making the varying forces easy to operate while remaining manufacturable with conventional tolerances.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2900151B1Detachable end effector and loader
Publication Date: 2020.04.29 ETHICON INC
  • EP2900151B1 patent drawingFigure 1
  • EP2900151B1 patent drawingFigure 2~3
  • EP2900151B1 patent drawingFigure 4

AI summary

A surgical device comprises an elongate shaft having an outer tube and an inner rod positioned in the outer tube. The outer tube and inner rod each comprise a distal end and a proximal end. An actuator is operably connected to the proximal ends of the outer tube and the inner rod. An end effector is adapted for in vivo attachment to and detachment from the elongate shaft. The end effector comprises an outer casing comprising a first detent mating feature adapted to engage the distal end of the outer tube; an inner shuttle axially moveable relative the outer casing, the shuttle comprising a second detent mating feature adapted to engage the distal end of the inner rod; and a pair of surgical jaws having an opened position and closed position dependant on the relative axial position of the shuttle and casing. A tubular loader is sized to receive the end effector, the tubular loader comprising third detent mating feature adapted engage end effector.