Dual Steerable Tricycle Stem Rotation Mechanism
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Solution Overview
Problem
Conventional tricycles lack a mechanism to seamlessly transition between rider-propelled and push-propelled modes without altering the distance between the seat and the head tube, leading to potential interference from the pedals and limited steering control when switching modes.
Innovation Solution
A tricycle design featuring a rotatable frame with a stem that supports the front wheel, allowing it to rotate about a transverse axis, and a handle that can be rotationally coupled or uncoupled from the stem to accommodate both modes of operation, maintaining a fixed distance between the seat and the head tube and optimizing pedal orientation and steering control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the tricycle is configured for rider propulsion with fixed seat-to-head tube distance, then the structure is simplified and manufacturing is easier, but pedal interference occurs and steering control is limited when switching to push mode
Solution Approach 1:
The stem is made rotatable about a vertical axis, allowing the front wheel assembly to be dynamically repositioned between two operational configurations: one optimized for rider propulsion and another for push-mode operation. This dynamic adjustment enables the same fixed-distance frame to accommodate both modes without structural modification.
Solution Approach 2:
The system changes the orientation parameter of the stem relative to the front wheel by rotating it about the vertical axis. This parameter change allows the front wheel to be positioned at different angles, optimizing performance for either rider control or push-mode steering while maintaining the fixed seat-to-head tube distance.
2Ease of operation
If the front wheel axis is repositioned for push-mode steering, then steering control is improved, but pedal interference with rider feet occurs
Solution Approach 1:
The rotatable stem allows dynamic repositioning of the front wheel assembly. In push mode, the stem rotates to position the front wheel axis for optimal steering control. In rider mode, the stem returns to its original position, properly spacing the pedals relative to the rider's feet and eliminating interference. This dynamic adjustment resolves the spatial conflict between the two operational modes.
Data Source
AI summary
A tricycle may be operable between a first mode of operation steerable by a tricycle rider, and a second mode of operation steerable by an individual pushing the tricycle. In both such first and second modes, the frame of the tricycle is configured to rotatably support the rear wheels and configured to support the head tube at a distance from the rear wheels such that a distance between the head tube and rear wheels need not necessarily be changed even when the front wheel axis location is changed from one mode to another.