In-prosthesis Linear Drive System Space Optimization
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Solution Overview
Problem
Conventional linear drive systems for prosthetics require significant internal space due to the need to mount power drives at the ends of screw rods, limiting design flexibility and increasing the overall dimensions of the prosthesis.
Innovation Solution
An in-prosthesis linear drive system that mounts a power drive on a holder frame, with a screw nut and screw rod limiter allowing the screw nut to drive the screw rod, enabling the screw nut to be positioned anywhere along the rod without restricting the power drive, thus minimizing internal space occupation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the power drive is mounted at the end of the screw rod to rotate it, then the linear drive system can be implemented, but the overall length of the prosthesis must be greater than the length of the screw rod, increasing the internal space requirement
Solution Approach 1:
Instead of mounting the power drive at the end of the screw rod to rotate it directly, the patent inverts the approach by mounting the power drive elsewhere on the holder frame and using it to rotate the screw nut, which then drives the screw rod. This inversion allows the power drive to be positioned within the internal space rather than extending beyond the screw rod length.
Solution Approach 2:
The screw nut acts as an intermediary component between the power drive and the screw rod. The power drive rotates the screw nut, which then converts rotational motion to linear motion of the screw rod through threaded engagement. This intermediary mechanism enables space-efficient positioning of the power drive while maintaining the linear drive function.
2Ease of operation
If the power drive is positioned beyond the screw rod area to avoid interfering with the screw nut movement, then the screw nut can move unimpeded, but the width of the internal space must be greater than the combined width of the screw rod and screw nut
Solution Approach 1:
The patent inverts the traditional arrangement by having the power drive rotate the screw nut instead of rotating the screw rod directly. This allows the power drive to be positioned within the holder frame rather than beyond the screw rod area, eliminating the need for additional width while maintaining unimpeded movement of the screw nut along the screw rod.
Solution Approach 2:
The patent repositions the power drive from a lateral position beyond the screw rod to a position within the holder frame structure, utilizing the vertical or depth dimension of the holder frame rather than requiring additional width. This dimensional repositioning allows the screw nut to move freely along the screw rod without spatial interference.
3Ease of manufacture
If the screw rod is made much longer than the screw nut to accommodate the power drive mounting, then the linear drive system can function, but the internal space occupation increases
Solution Approach 1:
Instead of extending the screw rod length to accommodate power drive mounting, the patent inverts the approach by mounting the power drive on the holder frame and having it rotate the screw nut. The screw rod length is determined only by the required stroke of the screw nut, not by power drive positioning requirements, thereby minimizing the length of the moving object.
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 configuration increases design flexibility, reduces internal space requirements, and allows for more compact prosthetic designs by enabling the power drive and screw nut to be displaced, allowing for more efficient use of space and enhanced operational stability with the addition of an adapter and buffer system.
Implementation Method 1
a screw nut (40) drivable by the second belt wheel (33) to rotate on its own axis, a screw rod (60) threaded into the screw nut (40)
Data Source
AI summary
An in-prosthesis linear drive system includes a holder frame, a power drive mounted on the holder frame, a screw nut mounted on the holder frame and coupled to the power drive and rotatable on the axis thereof by the power drive, a screw rod limiter including a center sliding guide rail mounted on the holder frame and a center sliding block slidable along the center sliding guide rail, and a screw rod threaded into the screw nut and connected with the center sliding block of the screw rod limiter and movable along the axial direction of the screw nut upon rotation of the screw nut. Thus, using the screw nut to drive the screw rod achieves the effect of minimizing the occupation of the prosthesis internal space.