Three-Axis Rotation Mechanism for Compact Radiotherapy Positioning
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Solution Overview
Problem
Existing mechanisms face challenges in providing three degrees of rotational adjustment in a compact and space-efficient arrangement, particularly in limited spaces such as beneath a patient couch during radiotherapy, where precise alignment of the therapeutic beam is required.
Innovation Solution
A three-axis tilting and rotation mechanism using non-parallel rotateable elements with wedge configurations allows for variable angular adjustments, with torque motors providing compact and elegant solutions, and a control apparatus ensures smooth alignment by compensating for accumulated rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional rotation mechanisms are used to provide three degrees of rotational freedom, then the required rotational adjustment capability is achieved, but the space occupied and device complexity increase significantly
Solution Approach 1:
The patent implements a nested rotation mechanism where a first rotation mechanism is positioned within a second rotation mechanism, which is itself positioned within a third rotation mechanism. This nesting arrangement allows three degrees of rotational freedom to be achieved in a compact configuration, minimizing the space occupied while maintaining full rotational adjustability capability.
2Adaptability or versatility
If conventional rotation mechanisms are used to provide three degrees of rotational freedom, then the required rotational adjustment capability is achieved, but the structural complexity and number of components increase
Solution Approach 1:
The patent merges multiple rotation mechanisms into a unified nested structure where the first, second, and third rotation mechanisms are integrated within each other. This combining approach reduces the overall structural complexity compared to using separate, independent rotation mechanisms, while still providing three degrees of rotational freedom. The nested configuration allows the mechanisms to share common structural elements and control systems.
3Area of stationary object
If rotational mechanisms are placed beneath the patient couch, then space efficiency is improved, but access for radiation source and patient comfort are compromised
Solution Approach 1:
The patent positions the rotation mechanisms in the vertical dimension beneath the patient couch, rather than occupying horizontal space that would interfere with patient access. By utilizing the space under the couch where the radiation source needs to pass through, the mechanism achieves compact arrangement without compromising patient comfort or access. The nested configuration minimizes the vertical profile to further reduce interference.
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
Enables precise and compact rotational adjustments, accommodating all six degrees of freedom while maintaining patient comfort and safety, allowing for precise positioning of the therapeutic beam without occupying excessive space.
Implementation Method 1
Wedge elements are placed between the rotateable elements in order to place their axes in a non-parallel arrangement. Since the rotation axes of the rotateable elements are not parallel, as one or more elements are rotated, the wedge elements that lie between them (or effectively lie between them) can be brought into and out of alignment.
Data Source
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AI summary
A three-dimensional rotation mechanism comprises three rotateable elements (50,56,60) fixed together in series, the first and second being fixed together with their rotational axes non-parallel, and the second and third being fixed together with their rotational axes non-parallel. Since the rotation axes of the rotateable elements are not parallel, as one or more elements are rotated, the wedge elements (54,58) that lie between them can be brought into and out of alignment. The rotateable elements are generally disc-shaped, such as in the form of torque motors. There is preferably a control apparatus for controlling the first, second and third rotateable elements to each rotate by a specific angle of rotation. A patient support is also described, comprising a table supported via a three-dimensional rotation mechanism as described above.