Nested Drive Unit in Bone Nail Device
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Solution Overview
Problem
Existing bone distraction devices, such as intramedullary nails, require complex drive arrangements for length adjustment and may not provide sufficient guidance for bone extension, compression, or transport, leading to potential misalignment and limited extension length.
Innovation Solution
A bone nail device with an inner tube and outer tube configuration, featuring a drive unit comprising a drive motor, transport screw, and planetary gear, allowing for sliding axial movement and integration within the device for compactness and ease of placement, with guiding features for precise trajectory control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a complex drive arrangement is used for length adjustment, then the bone distraction device can achieve sufficient guidance and control, but the device dimensions increase and placement becomes more difficult
Solution Approach 1:
The drive unit components (drive motor, planetary gear, transport screw) are nested within the inner tube, which itself is nested within the outer tube. This nested arrangement allows the complex drive mechanism to be contained within compact dimensions, resolving the contradiction between achieving sufficient guidance control and maintaining small device dimensions for easy placement.
2Length of moving object
If the drive parts are integrated within the bone nail device, then the device dimensions are minimized and placement is simplified, but the load-bearing capacity may be reduced
Solution Approach 1:
The device is segmented into functional modules: the drive motor, planetary gear, and transport screw are separate but integrated components within the inner tube. This segmentation allows each component to be optimized for its specific function while maintaining overall compactness, ensuring both minimal dimensions and sufficient load-bearing capacity through proper material selection and structural design.
3Device complexity
If the inner tubing allows sliding axial movement within the outer tubing, then the device achieves compactness and ease of placement, but the structural stability may be compromised
Solution Approach 1:
The inner tube is designed to slide axially within the outer tube, transforming the structure from static to dynamic. This dynamic configuration allows the device to maintain compactness for easy placement while providing the necessary movement capability for bone distraction, with the sliding mechanism itself becoming the functional element that enables both compactness and controlled instability for its intended purpose.
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 efficient bone extension, compression, and transport with reduced device dimensions, guided trajectories, and unobstructed operation within the bone, minimizing tissue interference and ensuring accurate bone alignment.
Implementation Method 1
a planetary gear (6) having an input end connected to the drive motor (7) and an output end connected to the transport screw (4)
Implementation Method 2
a transport screw (4) having an outer screw thread (4a) engaging the inner screw thread (2a) of the outer tubing (2)
Data Source
Figure 1
Figure 2A~2C
Figure 2D~2F
AI summary
Bone nail device (1), with an outer tubing (2) having an inner screw thread (2a) extending over at least a part of an inner surface of the outer tubing (2), and a first bone connection member (2b), and an inner tubing (3) having a second bone connection member (3a). The inner tubing (3) is arranged inside at least a part of the outer tubing (2) to allow a sliding axial relative movement. A drive unit is present, with a drive motor (7) fixedly attached to the inner tubing (3), and a transport screw (4) having an outer screw thread (4a) engaging the inner screw thread (2a) of the outer tubing (2). A planetary gear (6) is provided in the drive unit having an input end connected to the drive motor (7) and an output end connected to the transport screw (4).