Surgical Instrument Locking Mechanism With Spring-Defined End Positions

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Solution Overview

Problem

Existing surgical instruments face challenges in reliably and safely locking and releasing gripping limbs, often resulting in undefined intermediate positions that compromise the locking mechanism's functionality.

Innovation Solution

The surgical instrument incorporates a mechanical control arrangement with a spring device and pivot bearing to ensure the locking section is always in a defined end position, utilizing a positive control device for quasi-automatic transfer to the end position, and includes a delay unit to prevent unintentional rotation due to transverse forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking mechanism is used to lock gripping limbs, then the gripping limbs can be held in position, but undefined intermediate positions may occur leading to unreliable locking

Engineering Contradiction:
Improvelocking reliabilityVSAvoidoperation complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking section is designed to be rotatably displaceable between defined end positions rather than being fixed in translation, allowing dynamic positioning while maintaining reliability through defined stop positions that eliminate intermediate states

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The state of the locking section is changed from translational displacement to rotational displacement, with defined angular end positions that correspond to locked and unlocked states, eliminating undefined intermediate positions

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If manual intervention is required to position the locking section, then control is precise, but operating effort and complexity increase

Engineering Contradiction:
Improveoperating effortVSAvoidposition definition
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The spring device automatically transfers the locking section from an intermediate position to a defined end position without requiring manual intervention, reducing operating effort while maintaining position definition through the mechanical spring force

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring device is pre-loaded to automatically act on the locking section when released, performing the positioning action in advance before the operator needs to manipulate the control element further

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the locking section can rotate freely, then positioning is flexible, but unintentional rotation due to transverse forces may occur

Engineering Contradiction:
Improvepositioning flexibilityVSAvoidposition stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The locking section is designed with rotational freedom for positioning flexibility but incorporates defined end positions with mechanical stops that provide stability and prevent unintentional rotation beyond these defined positions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The delay unit acts as a protective mechanism that prevents unintentional rotation caused by transverse forces before such rotation can affect the locking state, cushioning against erroneous movements

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

4Extent of automation

If a mechanical control arrangement with spring device is used, then automatic positioning is achieved, but device complexity increases

Engineering Contradiction:
Improveautomatic positioningVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The spring device automatically positions the locking section without requiring additional actuators or complex control systems, achieving automatic positioning through a simple mechanical spring mechanism that self-regulates

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring device is integrated into the existing locking mechanism structure, combining the automatic positioning function with the locking section control rather than adding a separate complex positioning system

Inventive Principle:
Principle #5Merging (Combining)

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 design enhances the reliability and safety of locking and releasing the gripping limbs, simplifying operation by reducing the risk of malfunctions and undefined intermediate positions, while minimizing the need for manual intervention.

Implementation Method 1

The mechanical control arrangement can have a spring device for transferring the locking section of the male locking arrangement into an end position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

the locking section is rotationally guided by means of a pivot bearing

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4221628B1Surgical instrument having a blocking means
Publication Date: 2025.09.17 AESCULAP AG
  • EP4221628B1 patent drawingFigure 1~2
  • EP4221628B1 patent drawingFigure 3~4
  • EP4221628B1 patent drawingFigure 5~7

AI summary

A surgical instrument is known, which has two gripping limbs and a blocking means, which is provided in order to releasably lock the two gripping limbs relative to one another, wherein the blocking means has a female locking assembly in the region of one gripping limb and has a male locking assembly in the region of the other gripping limb, wherein the female locking assembly has a mechanical control device for locking and releasing a locking portion of the male locking assembly. According to the invention, a mechanical control assembly is assigned to the male locking assembly and is provided in order to move the locking portion of the male locking assembly out of an end position which defines a neutral position into an end position which defines a functional position and, conversely, out of the end position which defines the functional position into an end position which defines the neutral position, and the control assembly comprises securing means which are provided in order to secure the locking portion in both end positions. Use for open-surgery instruments.