Stationary Exercise Apparatus Foot Platform Angular Control
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Solution Overview
Problem
Existing stationary exercise apparatuses face challenges in balancing longer stride length and smaller foot platform angular variation, leading to discomfort and potential injuries due to excessive angular movement of the ankle joint.
Innovation Solution
The apparatus incorporates a crank mechanism with a planar four-bar linkage mechanism, including connecting, swing, supporting, and control members, which guides the foot platforms along specific paths to control angular variation, allowing for a longer stride length with controlled angular movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a longer crank arm is used to increase stride length and lifting height, then the displacement range of each foot platform is increased, but the angular variation of each foot platform becomes larger causing user discomfort and potential injury
Solution Approach 1:
The patent transitions from a conventional single-dimension crank motion to a two-dimensional elliptical motion path through the combination of crank mechanism and guide rail. This dimensional change allows the foot platform to achieve greater displacement range (longer stride length) while the guide rail constrains the angular variation, resolving the contradiction between stride length and angular variation.
Solution Approach 2:
The guide rail acts as an intermediary element between the crank mechanism and the foot platform. It mediates the motion transmission by converting the circular motion of the crank into elliptical motion along the guide rail, thereby achieving both increased stride length and controlled angular variation that would not be possible with the crank mechanism alone.
2Object-affected harmful factors
If a shorter crank is used to limit angular variation of foot platform, then user comfort is improved, but the leg stride length and lifting height become relatively short and low
Solution Approach 1:
By introducing the guide rail that provides a constrained elliptical path, the system achieves motion in an additional dimensional constraint. This allows shorter cranks to produce adequate stride length through the extended elliptical trajectory, while the guide rail simultaneously limits angular variation to maintain user comfort.
Solution Approach 2:
The motion control is segmented into two independent functions: the crank mechanism controls the vertical lifting motion, while the guide rail controls the horizontal and angular constraints. This segmentation allows each component to be optimized independently - the crank can be kept short for comfort while the guide rail provides the necessary stride length through its extended path.
Data Source
AI summary
A stationary exercise apparatus includes two connecting members each having an upper end guided to move along a circular path and a lower end coupled to a swing member, so that when the upper end moves along the circular path, the lower end moves along an arc-shaped path. Two supporting members are configured to support a user's feet, which are coupled between the upper end and the lower end of the respective connecting members and movable along a closed path. Two control members each is arranged between the corresponding supporting member and the corresponding swing member for guiding the second portion of the corresponding supporting member along a predetermined path, so that an angle formed between each supporting member and the corresponding connecting member varies as the corresponding swing member moves along the arc-shaped path between a first endpoint and a second endpoint.