Prosthetic Finger Worm Gear Transmission Assembly
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Solution Overview
Problem
Existing prosthetic hands face challenges such as complex assembly relationships, poor work reliability, and high costs due to intricate structures, including issues with cable transmission, tension springs, and differential designs for the thumb, leading to assembly difficulties and reduced service life.
Innovation Solution
A prosthetic finger design featuring a worm gear, rotating shaft, base joint rack, finger knuckles, tension spring, and transmission rope, with a grommet and bevel gears for secure connections and smooth rotation, reducing assembly complexity and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex transmission mechanisms (cable, bevel gear, worm gear) are used to achieve multi-degree-of-freedom movement, then the movement functionality is improved, but the structural complexity and assembly difficulty increase
Solution Approach 1:
The prosthetic finger is divided into three independent knuckles (base, proximal, distal), each capable of independent movement. The transmission mechanism is segmented into separate cable-driven systems for each knuckle, allowing simplified individual control while achieving complex overall functionality through coordination of segmented components.
Solution Approach 2:
The patent employs universal joint structures and standardized cable transmission mechanisms that can be applied across different knuckles and finger configurations. The base knuckle mounting rack and connection structures are designed to accommodate multiple functions (movement, force transmission, positioning) through integrated components rather than separate specialized parts for each function.
2Manufacturing precision
If multiple transmission components (cable, gear pairs, sliding screw pairs) are integrated for precise control, then the control precision is improved, but the assembly difficulty and manufacturing complexity increase
Solution Approach 1:
The patent extracts the complex gear transmission mechanisms from the prosthetic finger design and replaces them with direct cable-driven transmission systems. The cable transmission is taken out from within the finger structure and routed externally through guide holes, simplifying the internal structure while maintaining control precision through direct force transmission from motor to knuckle.
Solution Approach 2:
The patent introduces cable guide holes and mounting racks as intermediary structures that facilitate the cable transmission system. These intermediaries simplify the connection between motors and knuckles by providing structured pathways and mounting points, reducing the need for complex direct-coupling mechanisms while maintaining precise control.
3Reliability
If protective structures (fixing sleeve, sliding guide pin, compression spring) are added to protect transmission components, then the reliability is improved, but the device complexity and occupied space increase
Solution Approach 1:
The patent merges the protective functions into the existing structural components rather than adding separate protective elements. The cable guide holes serve both as structural support and as protective pathways for the transmission cables. The mounting rack integrates motor mounting, cable anchoring, and structural support functions into a single component, reducing overall complexity while maintaining reliability.
Solution Approach 2:
The patent nests protective and structural functions within existing components. The base knuckle mounting rack contains integrated features that provide both structural support and protection for transmission elements. Cable guide holes are nested within the knuckle structures, providing protected pathways for cables without adding external protective housings.
4Volume of moving object
If miniaturization is pursued to reduce occupied space, then the space efficiency is improved, but the structural simplicity and assembly ease are compromised
Solution Approach 1:
The patent employs dynamic cable routing through guide holes that allow the cables to move and adjust position based on knuckle movement. This dynamic arrangement allows compact packaging of the transmission system while maintaining adequate cable tension and alignment throughout the range of motion, achieving miniaturization without sacrificing structural simplicity.
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 design improves the reliability and assembly ease of prosthetic fingers, reduces the risk of failure, and lowers production costs by simplifying the structure and protecting critical components like the transmission rope and tension spring.
Implementation Method 1
a worm gear, a rotating shaft, a base joint rack, a finger base knuckle, a finger proximal knuckle, a finger distal knuckle
Implementation Method 2
worm gear engaged with the worm
Implementation Method 3
two ends of the tension spring are rotatably connected to the finger base knuckle and the finger proximal knuckle
Implementation Method 4
the distal end of the transmission rope is connected to the transmission rope connecting column, and a sleeving part is arranged on the finger distal knuckle and sleeved on the raised head part, and a part of the transmission rope is sandwiched between the sleeving part and the raised head part
Data Source
AI summary
The present invention provides a prosthetic finger. The prosthetic finger includes a finger mounting rack, a worm gear, a rotating shaft, a base joint rack, a finger base knuckle, a finger proximal knuckle, a finger distal knuckle, a tension spring, and a transmission rope, a grommet, a motor reducer assembly, a first bevel gear, a worm, a second bevel gear. The prosthetic finger can ensure that the connection of all the parts is reliable, the rotation of the worm gear is smooth, the tension spring is protected, and the transmission rope is not easy to fall off, so that the working reliability of the whole prosthetic finger can be improved and the possibility of failure can be reduced on the whole.