Radiotherapy Bed Tilting Mechanism for Backlash Control

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Solution Overview

Problem

Existing radiotherapy devices face issues with positional accuracy due to backlash from bearing tolerances, complicating operations and affecting pitch and roll control precision.

Innovation Solution

A bed for radiotherapy devices featuring a tilting unit with a first bearing, guide members, and a biasing unit to maintain a specific angle between flat plate members, preventing backlash and enabling precise inclination control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional bearing mechanisms are used for pitch control, then the structure is simple, but backlash due to bearing tolerance reduces positional accuracy

Engineering Contradiction:
Improvepositional accuracyVSAvoidmechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent converts the harmful effect of bearing tolerance and backlash into a beneficial feature by designing a mechanism where the second bearing's tolerance range defines a controlled angular region. The biasing unit maintains the first flat plate member within this tolerance region, transforming what would be precision-limiting backlash into a predictable, controlled operational zone that actually simplifies the overall mechanism while maintaining adequate accuracy.

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

Solution Approach 2:

The patent changes the operational parameter from requiring precise angular positioning to operating within a controlled angular region defined by the second bearing's tolerance. This parameter shift allows the system to accommodate bearing tolerance without compromising functional accuracy, as the biasing unit ensures the first flat plate member remains within the acceptable angular range throughout operation.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If roll and pitch control mechanisms are disposed in parallel and individually controlled, then both roll and pitch can be controlled simultaneously, but the position changes depending on the order of adjustment making operation complicated

Engineering Contradiction:
Improveroll and pitch control capabilityVSAvoidoperation simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent applies preliminary anti-action by using the biasing unit to pre-position the first flat plate member within the angular region defined by the second bearing's tolerance before roll adjustment begins. This preliminary positioning ensures that subsequent roll adjustments do not cause the first flat plate member to exit the controlled angular region, thereby preventing order-dependent position changes and simplifying operation.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The biasing unit performs a preliminary action by continuously maintaining the first flat plate member within the acceptable angular range throughout the adjustment process. This preliminary maintenance of positional integrity allows operators to adjust roll and pitch in any order without worrying about cumulative positioning errors, significantly improving ease of operation.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the angle between first direction and second direction is reduced to improve pitch control accuracy, then manufacturing precision improves, but the device complexity increases

Engineering Contradiction:
Improvepitch control accuracyVSAvoidguide member configuration complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary approach by using the second bearing as a mediator that defines an angular region rather than requiring precise angular alignment between guide members. The biasing unit acts as an intermediary mechanism that maintains the first flat plate member within this mediated angular region, achieving adequate pitch control accuracy without the need for complex, tightly-aligned guide member configurations.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution allows for highly accurate inclination control with a simple operation, reducing costs and maintaining positional accuracy during radiotherapy treatments.

Implementation Method 1

a biasing unit configured to selectively bias the first flat plate member and the second flat plate member with the first bearing as a rotation axis

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a first bearing configured to pivotally support a first flat plate member and a second flat plate member

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4635562A1Bed for radiotherapy equipment
Publication Date: 2025.10.22 HITACHI HIGH TECH CORP
  • EP4635562A1 patent drawingFigure 1
  • EP4635562A1 patent drawingFigure 2
  • EP4635562A1 patent drawingFigure 3

AI summary

Highly accurate inclination control of a bed for a radiotherapy device is implemented by a simple operation. The bed for the radiotherapy device includes the top plate 6 as a bed configured to allow a radiotherapy subject to lie thereon, and the tilting unit 5 configured to change an inclination of the top plate 6. The tilting unit 5 includes a first bearing (the bearing 19) configured to pivotally support a first flat plate member (the lower plate 11) and a second flat plate member (the upper plate 12) while maintaining a predetermined distance therebetween, a first guide member (the linear guide 15) provided parallel to the first flat plate member, the movement unit 17 configured to move the first guide member, a second guide member (the linear guide 16) provided in the movement unit 17 and inclined with respect to the first flat plate member, the connection member 20 connecting a second bearing (the bearing unit 18) and the second flat plate member with a predetermined distance therebetween, the second bearing being configured to move the second guide member, and a biasing unit (the elastic body 23) configured to selectively bias the first flat plate member and the second flat plate member with the first bearing as a rotation axis to cause an angle formed by the first flat plate member and the second flat plate member to be in a specific direction.