Steerable Crank Assembly for Simultaneous Drive and Steering
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Solution Overview
Problem
Existing Human Powered Vehicles (HPVs) with hand cranks face limitations in transferring power to rear-wheels, leading to reduced traction and performance, especially on uphill slopes, and compromised steering control due to the separation of power and steering systems, resulting in difficulty in achieving fine steering and stability.
Innovation Solution
A Steerable Crank System that integrates a Grooved Cog Wheel and a Crank Shaft with a Butterfly Connector, allowing simultaneous propulsion and steering by rotating the Crank Shaft, which acts as both a power delivery and steering mechanism, enabling efficient power transfer to rear-wheels while allowing for precise steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the hand crank power transfer system is permanently connected to the mainframe and separated from the steering system, then the power transfer structure is simplified and remains in line with the driving cog wheels, but the steering control is impeded when hands are on the crank, and the vehicle cannot maintain power transfer during steering maneuvers
Solution Approach 1:
The patent combines the power transfer function and steering control function into a single integrated hand crank assembly. The crank handles are positioned to allow simultaneous gripping for power application and manipulation for steering control, eliminating the need to separate hands from the crank during steering maneuvers. This merging of functions resolves the contradiction by maintaining both structural simplicity and operational ease.
Solution Approach 2:
The hand crank assembly is designed to serve multiple functions: power generation through cranking motion and steering control through handle manipulation. The crank handles act as both power input levers and steering control levers, allowing the same component to fulfill dual roles. This multi-functionality eliminates the need for separate steering mechanisms while maintaining power transfer capability during steering.
2Adaptability or versatility
If a chain is used to transmit power from the hand crank to the cog wheel, then the power transfer is flexible, but the chain twists and goes off the cog wheel when steering, restricting the steering angle to a relatively small angle
Solution Approach 1:
The patent segments the power transfer path from the steering function by using a rigid crank shaft for power transmission that remains parallel to the cog wheel axis during steering. The steering motion is achieved through the movement of the entire crank assembly relative to the frame, while the power transfer chain remains in a fixed plane relative to the cog wheel, preventing twisting and off-wheel disengagement.
Solution Approach 2:
The patent introduces a dimensional separation between steering motion and power transfer. Steering occurs in the horizontal plane through lateral movement of the crank assembly, while power transfer occurs in a vertical plane through the chain and cog wheel. This dimensional separation allows the chain to remain parallel to the cog wheel axis during steering maneuvers, eliminating the twisting problem and enabling larger steering angles.
3Ease of operation
If a long leverage at the crank connected by a pushrod to a short leverage at the vehicle wheel is used to transform steering angle, then the steering angle at the vehicle wheel is amplified, but fine steering is difficult to achieve due to disadvantageous transformation ratio and diminished sensitivity
Solution Approach 1:
The patent extracts the steering function from the power transfer mechanism, allowing independent optimization of each. The crank handles provide direct steering control through their positioning and movement, while the power transfer chain and cog wheel handle power transmission separately. This extraction eliminates the need for pushrod mechanisms and leverage transformation, preserving fine steering precision while still achieving adequate steering angle at the wheels through the direct geometric relationship of the crank assembly.
Data Source
AI summary
A Steerable Crank System including a Steerer Base firmly connected to the chassis/mainframe of a machine, said Steerer Base containing and supporting Grooved Cog Wheel situated in-line and parallel to the power driving direction in a manner that allows said Grooved Cog Wheel to rotate around its axis and drive the machine power, said Steerer Base containing and supporting a Fork in a manner that allows said Fork to rotate around its main axis and by that rotation movement it controls the steering, said Fork containing a 2nd axis supporting and housing a Crank Shaft in a manner that allows said Crank Shaft to rotate around its own axis, on said Crank Shaft attached a Butterfly Connector, said Butterfly Connector coupling together said Crank Shaft and Grooved Cog Wheel.