Ergometric Training Device Torque Measurement via Chain Tension
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Solution Overview
Problem
Existing exercise devices are complex and expensive when measuring the force or torque applied by alternately operable drive elements, particularly in distinguishing between left and right movements.
Innovation Solution
A pair of sensor means are arranged on a wheel connected synchronously to the drive elements, generating signals at specific angular positions offset by 180° to detect load changes between drive elements, allowing for simplified measurement and evaluation of force distribution between left and right extremities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges are attached to loaded components of the pedal assembly to measure torque, then torque measurement is achieved, but the device becomes very complex and expensive
Solution Approach 1:
The patent extracts the force measurement function from the complex pedal assembly strain gauge system and relocates it to a simpler chain tension measurement system. A force measuring element with a roller is introduced that presses against the chain, converting chain tension into a measurable force deflection that can be correlated to torque without requiring multiple strain gauges on complex pedal components.
Solution Approach 2:
The patent introduces a chain tensioner as an intermediary element between the drive chain and the measurement system. This tensioner, equipped with a force measuring element, acts as a mediator that translates the complex multi-point torque application on pedals into a single-point chain tension measurement, significantly simplifying the overall measurement system.
2Measurement precision
If separate force measurement for both pedal levers is implemented, then differentiated force measurement is achieved, but the device complexity increases significantly
Solution Approach 1:
The patent merges the measurement of forces from both left and right pedal levers into a single chain tension measurement system. By measuring the total chain tension and combining it with angular position information, the system can differentiate between left and right pedal forces without requiring separate measurement systems for each pedal, thus reducing overall complexity.
Solution Approach 2:
The patent adds the temporal/angular dimension to the measurement system. By incorporating angular position sensing alongside force measurement, the system can distinguish between forces applied at different points in the pedal cycle (left vs right pedal), effectively adding a dimensional aspect that enables differentiation without requiring physically separate measurement paths.
3Device complexity
If a chain tensioner with force measuring element is used, then the measurement process is simplified, but additional components are introduced
Solution Approach 1:
The patent designs the chain tensioner with a force measuring element to serve multiple functions: it acts as both a chain tensioning device (necessary for proper chain operation) and a force measurement sensor. This multi-functionality means that while an additional component is introduced, it replaces or consolidates what would otherwise require multiple separate components (tensioner plus separate measurement system), thus net reducing overall system complexity.
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
Enables accurate and reliable differentiation of forces exerted by each extremity, simplifying the measurement process and providing a more precise evaluation of training performance.
Implementation Method 1
a pair of sensor means which are arranged in positions relative to a wheel connected in a movement-synchronous manner to the drive, as a result of which a signal is generated when the wheel is arranged at one of two specific angular positions offset by 180° and which correspond to movement positions of a load change between the alternately operable drive elements
Data Source
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AI summary
The device has a measuring unit i.e. arm formed on a chain, to measure driving force applied by a manually or foot operated drive, or torque force associated with the drive. A measuring arrangement measures movement position i.e. angular position, of the drive. The arrangement has sensor units e.g. magnetic field sensors, arranged in mutually opposed positions with respect to a wheel connected to the drive in a movement synchronous manner. The mutually opposed positions correspond to a movement position of load change between alternately operated drive elements (16) i.e. foot operated pedals.