Accessory Lock Portion Mechanical Interlock for Thermoplastic Sheets
Solution Overview
Problem
Existing immobilization systems for patients during radiotherapy face challenges in securely attaching accessories like bite plates and ear inserts to low temperature thermoplastic sheets due to their low friction, anti-stick surfaces, limiting the size of attached accessories and detailed contouring of anatomical features.
Innovation Solution
An accessory device with a patient fixation portion and a locking feature that is mechanically fastened to the thermoplastic sheet, allowing the sheet to be formed around the locking feature, providing a secure mechanical interlock and preventing unintended separation, with various geometries and materials to ensure firm coupling and minimize air gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If accessories are attached to low temperature thermoplastic sheets using conventional methods, then the attachment process is simple, but the connection strength is insufficient due to low friction and anti-stick surfaces
Solution Approach 1:
The patent applies preliminary action by pre-forming protrusions on the accessory devices before attachment. These protrusions are designed to engage with corresponding recesses in the thermoplastic sheet, creating a mechanical interlock that overcomes the low friction and anti-stick properties of the thermoplastic material. The protrusions are formed as integral features of the accessories, ensuring secure connection without requiring complex attachment procedures.
2Area of stationary object
If larger accessories are attached to thermoplastic sheets, then more extensive anatomical contouring is achieved, but attachment security decreases due to the anti-stick surface properties
Solution Approach 1:
The patent applies preliminary action by pre-forming protrusions on the accessory devices before attachment. These protrusions are designed to engage with corresponding recesses in the thermoplastic sheet, creating a mechanical interlock that overcomes the low friction and anti-stick properties of the thermoplastic material. The protrusions are formed as integral features of the accessories, ensuring secure connection without requiring complex attachment procedures.
Solution Approach 2:
The patent applies local quality by creating localized engagement features (protrusions and recesses) at specific locations on the accessory devices and thermoplastic sheet. This localized mechanical interlock provides secure attachment at critical points while allowing the rest of the large accessory surface to maintain its contouring function. The protrusions are strategically positioned to ensure stable connection regardless of the overall accessory size.
3Manufacturing precision
If conventional attachment methods are used, then the immobilization system remains simple, but detailed contouring of anatomical features is limited
Solution Approach 1:
The patent applies preliminary action by pre-forming protrusions on the accessory devices before attachment. These protrusions are designed to engage with corresponding recesses in the thermoplastic sheet, creating a mechanical interlock that overcomes the low friction and anti-stick properties of the thermoplastic material. The protrusions are formed as integral features of the accessories, ensuring secure connection without requiring complex attachment procedures.
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 accessory device enhances the immobilization system by providing a secure and rigid connection between the accessory and the thermoplastic sheet, improving the quality and repeatability of immobilization, and allowing for more complex anatomical contouring and larger accessory sizes.
Implementation Method 1
forming the proximal surface of the low temperature thermoplastic sheet around the lock portion of the accessory device, such that the proximal surface of the low temperature thermoplastic sheet conforms to the lock portion
Data Source
AI summary
An accessory device and an immobilization system including the device are provided for positioning at least a portion of a patient's body relative to an immobilization device including a low temperature thermoplastic sheet. The accessory device may include a patient fixation portion and a lock portion. The patient fixation portion is attached to or inserted in the patient during use. The lock portion may extend distally from the patient fixation portion generally along a lock portion axis. The lock portion includes a shape, surface feature, or configuration, such that the low temperature thermoplastic sheet may be conformed to the outer surface of the lock portion of the accessory device, such that unintended separation of the accessory device from the low temperature thermoplastic sheet is prevented. Methods of forming the accessory device and immobilization system are also provided.