Multiple Small-Pitch Helical Drives for Actuator Force
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Solution Overview
Problem
Non-fluid linear and rotary actuators typically have low output force and torque due to the limitations of single large pitch helical screws, which restrict their ability to handle heavy-duty tasks effectively compared to fluid actuators.
Innovation Solution
The implementation of multiple small pitch helical drives in linear and rotary actuators, where a plurality of small pitch helical screws are used between a base panel and a rear panel, allowing rotation but not axial movement, with floating nuts and synchronized rotation, to enhance power and torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single large diameter helical screw is used to enhance buckling strength, then the structural strength is improved, but the pitch height increases which negatively affects the output force
Solution Approach 1:
The patent divides the single large-diameter screw into multiple small-diameter screws arranged in parallel. Each small screw has a smaller pitch height that provides greater mechanical advantage and output force, while the collective arrangement of multiple screws maintains the required buckling strength through distributed load bearing. This segmentation resolves the contradiction by allowing each component to be optimized for its specific function.
Solution Approach 2:
The patent combines multiple small-diameter screws working in parallel to achieve both high output force and high buckling strength. The floating nuts on each screw combine their individual force outputs, while the synchronized rotation through gear mechanisms ensures all screws contribute equally to the lifting action. This merging approach allows the system to overcome the limitations of single-screw designs.
2Device complexity
If a single large pitch lead screw is used, then the device complexity is reduced, but the productivity and power output are limited
Solution Approach 1:
The patent segments the drive system into multiple small-pitch screws instead of using a single large-pitch screw. This segmentation increases the mechanical advantage and power output by distributing the load across multiple threads with smaller pitch heights, while the modular nature of the segmentation allows for systematic arrangement and synchronization.
Solution Approach 2:
The patent introduces floating nuts as intermediary components that engage with multiple small-pitch screws simultaneously. These floating nuts act as mediators that combine the force output from multiple screws and transfer it to the load, enabling the system to achieve high power output while maintaining coordinated operation of all screw elements.
3Force
If multiple small pitch helical screws are used to increase output force, then the power output is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple small-pitch screw mechanisms into a unified system through the use of floating nuts and synchronized drive mechanisms. The floating nuts combine the force from multiple screws, while the gear-based synchronization system coordinates their rotation, creating a unified high-force output mechanism that manages complexity through systematic integration.
Solution Approach 2:
The patent designs the small-pitch screw system with universal characteristics where each screw and floating nut assembly can function independently yet contributes to the overall system. The modular design allows any subset of the screw-nut pairs to operate, providing redundancy and flexibility that simplifies the management of complexity while maintaining high force output capability.
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 provides increased power for linear actuators and torque for rotary actuators, enabling them to handle heavy-duty tasks more effectively by distributing force across multiple screws and utilizing helical pitch reduction for enhanced mechanical advantage.
Implementation Method 1
Multiple small pitch helical drives in linear and rotary actuators uses a plurality of small pitch helical screws in place of a single large pitch lead screw to provide increased power or force
Implementation Method 2
utilizing helical pitch reduction for enhanced mechanical advantage
Implementation Method 3
the heads of the screws may extend through the base panel and have spur gears mounted thereon, including a central screw having a central drive gear surrounded by a plurality of driven gears that mesh with the central drive gear
Implementation Method 4
A piston head having spaced disks includes floating nuts disposed in sockets on the disks for each of the screws, the piston head being free to travel on the screws between the base panel and the rear panel as the screws are rotated
Data Source
AI summary
The multiple small pitch helical drives in linear and rotary actuators uses a plurality of small pitch helical screws in place of a single large pitch lead screw to provide increased power or force in a linear actuator or increased torque in a rotary actuator. The multiple small pitch helical drive includes a plurality of screws disposed between a base panel and a rear panel in a rigid skeleton, the screws having a single degree of freedom, i.e., they are free to rotate, but cannot move axially. A piston head having spaced disks includes floating nuts disposed in sockets on the disks for each of the screws, the piston head being free to travel on the screws between the base panel and the rear panel as the screws are rotated. The helical pitch reduction provided results in increased force output and increased torque for linear and rotary actuators.