Ergonomic Stair Stepper Mechanism Resolving Dead Point
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Solution Overview
Problem
Conventional stair steppers suffer from non-ergonomic paths and a 'dead point' issue, where the mechanism becomes difficult to operate when the crank and link overlap, leading to insufficient climbing force and unrealistic simulation of stepping or stair-climbing.
Innovation Solution
The exercise device features a frame with two pedals, first and second swing arms, a resistance device, link rods, cranks, limiting rods, and roller assemblies, allowing for an ergonomic arc-shaped path that simulates stepping, striding, or stair-climbing by providing sufficient climbing force and avoiding the 'dead point' through adjustable inclination and direct force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional stair stepper mechanisms use a simple crank and rod linkage, then the device structure is simple, but the pedal path is non-ergonomic and cannot simulate real stepping motion
Solution Approach 1:
The mechanism is divided into multiple swing arms (first and second swing arms) connected in sequence between the frame and pedal, with each swing arm contributing to the overall arc-shaped motion path. This segmentation allows the complex ergonomic path to be achieved through simpler individual components working together.
Solution Approach 2:
The pedal is designed to move along an arc-shaped path centered at the user's body, creating a curved motion trajectory that mimics natural stepping or stair-climbing motion. The first and second swing arms are positioned and dimensioned to generate this curved path, improving ergonomics.
2Productivity
If the crank and link are operated to overlap in conventional steppers, then the mechanism reaches aĉé position, but a dead point is created making it difficult to further move the crank
Solution Approach 1:
The mechanism uses two swing arms arranged in a plane, where the second swing arm is positioned at a different angular dimension relative to the first swing arm. This dimensional arrangement ensures that when the first swing arm reaches its limit position, the second swing arm is still at an angle that allows continued motion, eliminating the dead point.
Solution Approach 2:
The limiting rods are positioned to constrain the swing arms before they can reach a dead point configuration. This preliminary constraint prevents the crank and link from overlapping in a way that would create a dead point, ensuring continuous smooth motion throughout the exercise range.
3Ease of operation
If conventional stair steppers use insufficient climbing force, then the mechanism operates smoothly, but the simulation of stepping or stair-climbing is unrealistic
Solution Approach 1:
The resistance device is designed to provide variable resistance that dynamically adjusts during the pedal stroke, increasing the climbing force when needed to simulate realistic stair-climbing conditions. The swing arm mechanism also dynamically changes the mechanical advantage throughout the motion range, providing sufficient climbing force during the upward phase of each step.
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
The ergonomic path design enhances the realism and safety of the exercise by providing a smooth and unhindered operation, effectively overcoming the 'dead point' problem and ensuring sufficient climbing force, allowing for efficient and safe simulation of stepping, striding, or stair-climbing exercises.
Implementation Method 1
Each roller assembly couples to a corresponded second swing arm of the two second swing arms and slidably couples to a corresponded limiting rod of the two limiting rods
Data Source
AI summary
An exercise device is provided with a frame, two pedals, two first swing arms, two second swing arms, a resistance device, two link rods, two cranks, two limiting rods, and two roller assemblies. Each first swing arm has two ends, in which one end pivotally connects to the frame, and the other connects to one of the two second swing arms. Each second swing arm has two ends, in which one end connects to one first swing arm, and the other connects to one pedal. The resistance device has an axle. Each crank includes two ends, one end connecting to the axle, and the other connecting to one link rod. Each link rods includes two ends, one end connecting to one crank, and the other connecting to an area of one second swing arm. Each roller assembly connects to one second swing arm, and can slide along one limiting rod.