Linearly Actuated Recumbent Vehicle with Coiling Power Link
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional recumbent human-powered vehicles, such as bicycles and tricycles, often have long wheelbases and low muscle efficiency due to their crank transmission systems, making them difficult to maneuver, slow, and inefficient for carrying loads.
Innovation Solution
A recumbent human-powered vehicle design featuring a linear drive mechanism connected by flexible power links to a double overrunning clutch transmission with returning springs, allowing for a short wheelbase, efficient power transfer, and the ability to propel the vehicle with alternating or simultaneous leg motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a crank transmission system is used in recumbent human-powered vehicles, then the vehicle can be propelled with alternating leg motion, but the muscle efficiency is low (24% or less) and the wheelbase becomes long
Solution Approach 1:
The pedal drive system is segmented into independent left and right pedals that can move separately in a rectilinear path, rather than being connected through a crank mechanism. This allows each leg to contribute power independently during the power stroke while the return stroke is handled by spring-loaded clutches, eliminating the efficiency losses of crank transmission.
Solution Approach 2:
The traditional crank transmission mechanism is replaced with a direct linear drive system using bell cranks and overrunning clutches. This substitution eliminates the intermediate rotational conversion and reduces mechanical losses, achieving up to 90% muscle efficiency by directly transmitting linear pedal motion to the drive chain.
2Length of moving object
If pedals are positioned in front of the front wheel with a linear drive mechanism, then the wheelbase is shortened and maneuverability is improved, but the power transfer efficiency was previously insufficient
Solution Approach 1:
The bell cranks are designed to pivot dynamically during pedal motion, converting the rectilinear pedal movement into rotational motion that drives the chain. This dynamic mechanism allows the pedals to be positioned forward of the front wheel with a short wheelbase while maintaining efficient power transfer through the overrunning clutch system.
Solution Approach 2:
Bell cranks serve as intermediary mechanisms between the linearly moving pedals and the rotational chain drive. These bell cranks convert the horizontal rectilinear motion of the pedals into rotational motion that can drive the chain, enabling efficient power transfer despite the shortened wheelbase configuration.
3Length of moving object
If a short wheelbase is achieved by positioning pedals above the front wheel, then maneuverability is improved, but the vehicle requires a novel transmission system to maintain efficiency
Solution Approach 1:
The overrunning clutch mechanism serves multiple functions: it allows power transmission during the forward power stroke, permits free rotation during the return stroke, and can handle alternating or simultaneous leg motion. This multi-functional design achieves short wheelbase maneuverability without requiring separate complex mechanisms for each function.
Solution Approach 2:
The transmission system uses variable engagement parameters through spring-loaded clutches that engage and disengage based on the direction of force applied. During the power stroke, the clutch engages to transmit force; during the return stroke, the clutch disengages to allow free movement. This parameter-based control simplifies the overall system while maintaining efficiency.
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 design achieves higher speeds, increased muscle efficiency (up to 90%), and the ability to carry heavier loads, providing a more comfortable and efficient alternative to conventional bicycles and tricycles for local travel.
Implementation Method 1
double overrunning clutch transmission with returning springs
Data Source
AI summary
Vehicle including a frame, a seat, a wheel, a drive sprocket arranged on the wheel, a main drive sprocket, a transmission member coupling the drive sprockets, a pedal slider arranged in front of the seat and which swings forward and rearward, and a drive mechanism including an overrunning clutch system connected to the main drive sprocket. A power link is connected at a first end region to the pedal slider and at a second end region to the clutch system. Forward movement of the pedal slider causes movement of the power link and rotation of the clutch system which causes movement of the main drive sprocket and the wheel drive sprocket resulting in rotation of the wheel. The clutch system includes a drum including a groove in which the power link is retained.