Surgical Rotation Stop Assembly for Multi-Turn Knob Control

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Solution Overview

Problem

Existing rotation stop devices for surgical instruments typically limit rotation to less than 360 degrees and are bulky, making it difficult to package them within instruments or devices requiring greater rotation ranges.

Innovation Solution

A rotation stop device featuring a threaded shaft and nut configuration that allows limited rotation greater than 360 degrees, with a low profile design and a sensor for detecting rotational position to adjust electronic displays, facilitating packaging and preventing damage to components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If existing rotation stop devices are used to limit rotation, then rotation is limited to less than 360 degrees, but the device becomes bulky and difficult to package

Engineering Contradiction:

Improverotation limit precisionVSAvoiddevice size

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The rotation stop device is nested within the handle assembly of the surgical instrument. The follower is received within a cavity in the handle, and the helical thread is formed on an insert that is received within the same cavity. This nesting arrangement allows the rotation stop mechanism to be integrated into the existing instrument structure without adding significant external dimensions, resolving the contradiction between providing precise rotation limiting and maintaining a compact form factor.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from limiting rotation to less than 360 degrees (single revolution) to enabling rotation greater than 360 degrees (multiple revolutions). This is achieved by allowing the follower to travel axially along the helical thread for multiple cycles before engaging the rotation limit feature. The rotation stop mechanism now operates in an extended rotational dimension, allowing the knob to rotate multiple times while still providing precise rotation limiting through the axial travel of the follower along the helical path.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If rotation range is increased to greater than 360 degrees, then component stress is reduced, but existing rotation stop devices cannot accommodate this range

Engineering Contradiction:

Improvecomponent stress protectionVSAvoidrotation range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The rotation stop mechanism uses a dynamic follower that travels axially along the helical thread as the knob rotates. This dynamic interaction allows the mechanism to accommodate multiple revolutions (greater than 360 degrees) while maintaining rotation limiting functionality. The follower's axial position changes continuously during rotation, enabling the system to adapt to extended rotation ranges while still providing reliable component protection through the rotation limit feature.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the rotation stop mechanism by modifying the helical thread geometry and the follower's engagement characteristics. The helical thread is configured with specific pitch and lead angle parameters that enable multiple revolutions before the follower reaches the rotation limit position. This parameter adjustment allows the mechanism to provide both extended rotation range (greater than 360 degrees) and reliable component stress protection, resolving the contradiction between adaptability and reliability.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If fixed mechanical stops are used at discrete angular positions, then rotation is limited, but the rotation range is less than 360 degrees

Engineering Contradiction:

Improverotation limit controlVSAvoidrotation range

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The invention replaces discrete angular stops with a continuous helical thread geometry. The helical thread forms a curved, spiral path that the follower travels along during rotation. This curved geometry naturally limits rotation to a specific range (greater than 360 degrees) while maintaining precise control through the continuous axial progression of the follower along the helical path, rather than relying on discrete angular positions. The helical curvature enables both precision and extended rotation range simultaneously.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 precise control of rotation greater than 360 degrees while maintaining a compact form factor, preventing stress on components like wires and optical fibers, and allowing for real-time image adjustments based on detected rotation.

Implementation Method 1

A rotation stop device featuring a threaded shaft and nut configuration that allows limited rotation greater than 360 degrees

Methodology Applied

Scientific EffectScrew mechanism: Screw

Data Source

PatentEP3944054B1Surgical instruments with rotation stop devices and related methods

Publication Date: 2024.01.17 MEDOS INT SARL

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AI summary

Surgical instruments with rotation stop devices and related methods are disclosed herein, e.g., for providing limited rotation between first and second components of the surgical instrument in a range greater than 360 degrees. Exemplary rotation stop devices can have a low profile and can include various features to facilitate packaging of the device within a larger instrument.