Hypoid Gear Module for Surgical Table Positioning

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Solution Overview

Problem

Existing surgical operating table additional modules are heavy and lack precision in adjustment, with safety concerns during electrical failures.

Innovation Solution

A motorized module with a hypoid gear mechanism for precise positioning, featuring a geared motor and angular position sensor, and torque limiting means to ensure safety and low mass, allowing pivoting of the support up to 180° and secure locking in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional motorized adjustment mechanisms are used, then positioning capability is provided, but the mass of the additional module becomes excessive and precision is insufficient

Engineering Contradiction:
Improvepositioning precisionVSAvoidmodule mass
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent changes the fundamental parameters of the gear mechanism by using a hypoid gear instead of conventional parallel-axis gears. This allows for a higher reduction ratio (e.g., 60:1 or higher) in a more compact configuration, achieving finer positioning precision (angular resolution below 0.1 degrees) while reducing the overall module mass by optimizing the transmission system efficiency and compactness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional mechanical adjustment mechanisms with an electric motor-driven hypoid gear system. This substitution enables more precise control through electronic actuation while reducing the mechanical complexity and mass of manual adjustment mechanisms, achieving positioning precision through motor control rather than manual mechanical adjustment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional gear mechanisms are used, then torque transmission is provided, but the mechanism is reversible causing safety issues during electrical failure

Engineering Contradiction:
Improvesafety during electrical failureVSAvoidgear mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent converts the potential harm of gear reversibility (safety issue during electrical failure) into a benefit by using the self-locking property of hypoid gears. The orthogonal non-concurrent axis configuration creates inherent friction and geometric interference that prevents backward motion, so that when electrical power fails, the gravitational force on the patient's body cannot reverse the gear rotation, automatically maintaining the positioned state without requiring additional complex locking mechanisms.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The hypoid gear mechanism provides beforehand cushioning against the harmful effect of electrical failure by its inherent non-reversibility. The gear geometry and friction characteristics are designed to anticipate and prevent unintended movement before it can occur, ensuring that even under gravitational load during power loss, the module maintains its position without requiring active braking or additional safety systems.

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

3Force

If high reduction ratio is achieved through conventional gears, then output torque is increased, but the mechanism becomes complex and less compact

Engineering Contradiction:
Improveoutput torqueVSAvoidgear mechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent transitions from conventional parallel-axis gear arrangements to a hypoid gear configuration where the input and output axes are orthogonal (at 90 degrees) and non-concurrent. This dimensional change in the gear geometry allows for a more compact spatial arrangement that achieves high reduction ratios (60:1 or higher) without requiring multiple gear stages, reducing the overall mechanism complexity while maintaining high output torque capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the geometric parameters of the gear system by using hypoid gears with spiral or helical toothing on orthogonal non-concurrent axes. This parameter change enables a single-stage or reduced multi-stage transmission to achieve the same or higher reduction ratio that would require complex multi-stage conventional gear trains, simplifying the mechanism while increasing output torque through optimized gear ratios.

Inventive Principle:
Principle #35Parameter changes

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 module provides high precision in positioning with reduced operator effort, maintains safety during electrical failures, and is lightweight for easy handling, enabling versatile patient positioning for surgical procedures.

Implementation Method 1

the articulation means comprise at least one hypoid gear comprising a toothed wheel input driven by the motor and meshing with an output toothed wheel

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

said module comprising at least one electric motor capable of being controlled so as to actuate the articulation means and cause the support to pivot

Methodology Applied
Scientific EffectElectric motor: Linear Motor

Data Source

PatentEP3906912B1Additional motorised module intended for equipping a surgical operating table
Publication Date: 2022.12.28 STERIS
  • EP3906912B1 patent drawingFigure 1~2
  • EP3906912B1 patent drawingFigure 3~4
  • EP3906912B1 patent drawingFigure 5~7

AI summary

The invention relates to an additional module (2) intended to equip a surgical operating table (1), comprising a support (11) intended to support a part of a patient's body, removable fixing means (9) capable of being removably fixed to complementary fixing means (10) of the operating table (1), articulation means (8) located between the fixing means (9) and the support (11), capable of allowing pivoting about at least one axis of rotation (8') of said support (11) relative to the fixing means (9), said module (2) comprising at least one electric motor (13) capable of being controlled so as to actuate the articulation means (8) and to pivot the support (11), characterized in that the articulation means (8) comprise at least one hypoid gear comprising an input gear driven by the motor and meshing with an output gear.