Surgical Pistol Grip Gearbox With Spring Overload Protection

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Solution Overview

Problem

Existing electrosurgical instruments with pistol grips face issues of ergonomic design, space utilization, and component overload due to high operating forces, which can lead to damage.

Innovation Solution

A surgical pistol grip with an integrated gearbox and overload protection element that converts pivoting movements into translational forces, incorporating a spring mechanism to absorb excessive forces and protect the transmission components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a rigid gearbox housing is used to transmit high operating forces, then force transmission capability is improved, but the risk of component overload and damage increases

Engineering Contradiction:
Improveforce transmission capabilityVSAvoidcomponent overload protection
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent incorporates an elastic element (spring) in the actuating mechanism that acts as a cushioning element. This spring is positioned to absorb excess forces before they can damage the gearbox components. When the actuating lever is pulled, the spring compresses and absorbs the force, preventing direct transmission of potentially damaging forces to the gearbox teeth and other components.

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

2Ease of operation

If the pistol grip design is made compact and ergonomic, then ease of operation is improved, but space for transmission components is reduced

Engineering Contradiction:
Improveergonomic designVSAvoidspace for transmission components
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent places the gearbox inside the pistol grip housing, effectively nesting one component within another. The gearbox is positioned within the available space of the pistol grip, allowing the actuating lever to pivot within the housing while maintaining a compact overall design. This nesting approach allows sufficient space for transmission components while keeping the external dimensions compact and ergonomic.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If the actuating lever is made manually operable with finger guidance, then ease of operation is improved, but the complexity of the actuating mechanism increases

Engineering Contradiction:
Improvemanual actuationVSAvoidactuating mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The spring-loaded actuating mechanism is designed to automatically reset after each actuation. After the actuating lever is pulled and releases the locking element, the spring automatically pushes the lever back to its initial position, preparing it for the next actuation without requiring manual intervention. This self-service feature simplifies the overall operation while maintaining manual control.

Inventive Principle:
Principle #25Self-service

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

The design provides an ergonomic, space-saving solution that effectively transmits forces while safeguarding the instrument's components from overload, ensuring reliable operation and longevity.

Implementation Method 1

an elastic element (102), in particular a spring, which is arranged in the power flow between the actuating lever (22) and the rotating part (82) and which absorbs an excess force applied to the actuating lever (22)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A manually operated, preferably finger-guided, actuating lever (22) is pivotally mounted to the handle. This lever can be held—for example, in a monkey grip—by several fingers of an operator's hand and manually pulled towards the handle, particularly the grip element, to activate the trigger. This pulling/actuating movement of the actuating lever/trigger is transmitted via a gearbox housed within the transmission mechanism inside the instrument shaft

Methodology Applied
Scientific EffectSpring mechanism: Spring

Data Source

PatentEP4580527B1Surgical pistol grip, and surgical instrument comprising pistol grip
Publication Date: 2026.03.11 AESCULAP AG
  • EP4580527B1 patent drawingFigure 1
  • EP4580527B1 patent drawingFigure 2~3
  • EP4580527B1 patent drawingFigure 4~7

AI summary

The invention relates to a surgical shaft assembly (6) of or for a surgical instrument (2) and to a surgical instrument (2), in particular a minimally invasive shaft-type electrosurgical instrument (2), comprising the shaft assembly (6), wherein a gearing mechanism (24) has a rotary part (82), which is rotatably hinged to a gearing mechanism housing (20), and an elastic overload protection element (102), which couples a pivoting movement of an actuation lever (22) to a rotation of the rotary part (82).