Operating Table Height Adjustment via Dual Rack and Gear Mechanism

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Solution Overview

Problem

Operating tables in surgical settings require versatile and reliable height adjustment mechanisms that allow for easy patient positioning and ergonomic working conditions while maintaining mobility and ease of cleaning, but existing solutions often compromise on construction complexity and motion distance.

Innovation Solution

A height adjustment arrangement featuring a first rack bar attached to the base, a lifting element, a second rack bar attached to the table top, and a system of at least three gear wheels that enable the second rack bar to move twice the distance of the lifting element, ensuring a low construction with a simple and reliable mechanism that maintains table top inclinations during elevation and lowering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a height adjustment mechanism is designed to provide a large motion distance for the table top, then the motion distance is improved, but the construction height and complexity increase

Engineering Contradiction:
Improvemotion distance of table topVSAvoidconstruction height
Core Design Contradiction:
Length of moving objectVSLength of stationary object

Solution Approach 1:

The patent introduces a lifting element as an intermediary component between the actuator and the table top. This lifting element translates the actuator's linear motion into rotary motion of the first gear wheel, which then drives the second gear wheel to move the second rack bar. This intermediary mechanism enables a compact construction while achieving a large motion distance for the table top.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces a direct linear motion mechanism with a gear-based rotary motion system. By using gear wheels engaged with rack bars, the system converts the actuator's linear displacement into rotary motion, which is then converted back into linear motion of the second rack bar. This mechanical substitution allows for a more compact design with reduced construction height while maintaining a large motion distance.

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

2Device complexity

If a height adjustment mechanism uses a simple mechanism with few components, then the device complexity is reduced, but the reliability and operational smoothness deteriorate

Engineering Contradiction:
Improvenumber of gear wheels and componentsVSAvoidoperational reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The lifting element serves as a mediator that coordinates the motion between the first and second rack bars. By introducing this intermediate component with guide surfaces, the system ensures smooth and reliable operation while maintaining a relatively simple overall structure. The lifting element's interaction with both rack bars through guided motion enhances operational reliability without significantly increasing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the tooth systems of gear wheels are arranged with coplanar circumferential center lines, then the manufacturing and assembly are simplified, but the motion transmission efficiency may be compromised

Engineering Contradiction:
Improvealignment and assembly easeVSAvoidmotion transmission efficiency
Core Design Contradiction:
Ease of manufactureVSPower

Solution Approach 1:

The patent applies different spatial arrangements to different parts of the gear system. The first gear wheel is positioned with its circumferential center line coplanar with the second gear wheel's center line for ease of manufacture and assembly. However, the third gear wheel is positioned at a different location to optimize motion transmission. This local differentiation of spatial arrangement maintains manufacturing simplicity while ensuring efficient power transmission.

Inventive Principle:
Principle #3Local quality

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 arrangement allows for a large motion distance with a compact design, ensuring reliable operation and easy cleaning, while maintaining ergonomic flexibility and mobility of the operating table.

Implementation Method 1

at least one gear wheel which is connected rotatably to the lifting element and engaged to operate with tooth systems of the first rack bar and the second rack bar, such that the linear motion of the lifting element relative to the first rack bar displaces the second rack bar linearly relative to the lifting element

Methodology Applied
Scientific EffectGear mechanism: Gear

Data Source

PatentEP3456304B1Height adjustment arrangement for an operating table
Publication Date: 2020.03.04 MERIVAARA
  • EP3456304B1 patent drawingFigure 1~2
  • EP3456304B1 patent drawingFigure 3
  • EP3456304B1 patent drawingFigure 4

AI summary

The height adjustment arrangement for an operating table (10) comprises a first rack bar (1) which is attachable to a base (8) of the operating table (10), a lifting element (3) which is movable relative to the first rack bar (1) linearly in a longitudinal direction of the first rack bar (1), a second rack bar (2) which is attachable to a table top (11) of the operating table (10) and movable relative to the lifting element (3) linearly in a longitudinal direction of the first rack bar (1), an actuator (7) which is adapted to drive the lifting element (3) linearly relative to the first rack bar (1) in a longitudinal direction of the first rack bar (1), and at least one gear wheel (4a, 4b, 4c) which is connected rotatably to the lifting element (3) and engaged to operate with tooth systems of the first rack bar (1) and the second rack bar (2), such that the linear motion of the lifting element (3) relative to the first rack bar (1) displaces the second rack bar (2) linearly relative to the lifting element (3) in such a way that, as the lifting element (3) is being operated, the motion direction of the second rack bar (2) is the same as that of the lifting element (3).