Thumb Trigger Control Device Decoupling Grasp and Actuation
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Solution Overview
Problem
Existing manual control devices for machines, such as motorcycles and portable tools, often require a vigorous grasp, leading to hand fatigue and imbalance, as they necessitate continuous control actions that strain the wrist and fingers, compromising both control precision and grip stability.
Innovation Solution
A manual control device featuring a handle with a trigger actuated by the distal phalanx of the thumb, allowing the proximal phalanx to remain on the handle, enabling a firm grasp while allowing sensitive and prolonged control without wrist flexion, thus decoupling the grasping and control muscles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional controls mounted on handles are used, then control operation is enabled, but grasp stability deteriorates due to finger or wrist movement requirements
Solution Approach 1:
The thumb is segmented into two functional zones: the proximal phalanx maintains continuous contact with the handle for grasp stability, while the distal phalanx independently actuates the trigger for control operation. This segmentation allows both grasp stability and control operation to function simultaneously without interference.
Solution Approach 2:
The trigger mechanism serves as an intermediary element that translates the distal phalanx movement into control system actuation while allowing the proximal phalanx to maintain grasp on the handle. The trigger articulation point acts as a mediator that decouples the grasp function from the control function.
2Reliability
If vigorous grasp of the handle is maintained, then safety and holding capacity are improved, but control precision deteriorates due to muscle strain
Solution Approach 1:
The thumb muscles are functionally segmented into grasping muscles (acting on proximal phalanx) and control muscles (acting on distal phalanx). This segmentation prevents muscle strain from propagating between functions, allowing vigorous grasp to be maintained without compromising control precision through muscle fatigue or cramp.
Solution Approach 2:
Different parts of the thumb are assigned different functional qualities: the proximal phalanx region is optimized for grasping with high force generation, while the distal phalanx region is optimized for precise control movements. This local differentiation allows each region to operate at its optimal performance level without interfering with the other.
3Duration of action of moving object
If continuous control action is required, then system control is enabled, but hand fatigue increases due to sustained muscle exertion
Solution Approach 1:
The continuous control action is segmented from the grasp function, allowing the distal phalanx to perform sustained control movements while the proximal phalanx maintains a static, energy-efficient grasp position. This segmentation prevents the accumulation of fatigue in the grasping muscles while enabling prolonged control operation.
Solution Approach 2:
The trigger mechanism is designed to be actuated by the natural movement of the distal phalanx without requiring additional muscular effort from the grasping muscles. The system uses the inherent mobility of the distal phalanx to self-service the control function, minimizing overall hand fatigue during continuous operation.
Data Source
AI summary
A manual control device including a handle configured to be grasped by a hand with a thumb, and a trigger configured to be subjected to a pressure from the distal phalanx of the thumb. The trigger is placed relative to the handle so as to be able to be subjected to a pressure from the distal phalanx while the proximal phalanx from the thumb is resting along the handle.