Exercise Machine Loading Device with Nitrogen Spring Force Triangle
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Solution Overview
Problem
Existing loading devices for exercise machines, such as those using bow springs and lever systems, lack convenient and finite adjustability, often requiring complex adjustments that are inconvenient and difficult to perform, especially under spring loads.
Innovation Solution
A loading device featuring a force triangle with a slidable coupling mechanism that self-supports a nitrogen gas cylinder and lever arm, allowing for easy adjustment of load points without requiring manual dexterity or interrupting the exercise routine, utilizing a pivotally mounted compression spring and lever arm with a slidable coupling that maintains support throughout the exercise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lever and spring systems are used to provide resistance, then a wide range of loading options is available, but adjustment of the leverage is difficult and inconvenient due to the need to simultaneously change the lengths of two legs of the force triangle
Solution Approach 1:
The force triangle is segmented into adjustable components: the lever arm length can be changed independently by moving the pivot point along the lever arm, while the spring attachment point remains fixed. This segmentation allows adjustment of one leg without requiring simultaneous adjustment of the other legs, making the system adaptable while easy to operate.
Solution Approach 2:
The lever arm is designed with a movable pivot point that can be repositioned along its length, creating a dynamic adjustment mechanism. This allows the user to change the leverage ratio by simply moving the pivot point, rather than requiring complex simultaneous adjustments of multiple components, thus improving ease of operation while maintaining versatility.
2Object-generated harmful factors
If preloaded spring is used to reduce high spring rate effects, then loading increase through exercise stroke is reduced, but adjustment of the lever arm becomes difficult and inconvenient when the spring is in rest position
Solution Approach 1:
The preloading function is extracted from the main spring and implemented through a separate mechanism: a cable connected to a weight stack provides the preload force independently of the main exercise spring. This allows the main spring to be adjusted for optimal performance during exercise without being constrained by adjustment difficulties in the rest position, resolving both the harmful rapid loading and the adjustment convenience issues.
Solution Approach 2:
A cable and weight stack system is introduced as an intermediary mechanism to provide the preload function. This intermediary system independently manages the preload requirement, allowing the main exercise spring and lever arm to be optimized for exercise performance without compromising adjustment ease, thus eliminating both the rapid loading problem and the adjustment difficulty.
3Device complexity
If adjustment points are located along an arc with radius equal to spring leg length, then only single leg of force triangle needs to be changed for loading adjustments, but the spring must be locked or lever arm latched during exercise stroke
Solution Approach 1:
The lever arm is designed with pre-positioned adjustment holes at specific locations along its length, allowing the pivot point to be quickly repositioned before exercise begins. This preliminary preparation of adjustment positions eliminates the need for complex locking or latching mechanisms during exercise, as all adjustments can be made in advance when the system is stationary and safe to manipulate.
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 smooth, quiet, and convenient adjustment of loads with minimal user effort, providing a wide range of finite load settings and supporting small loadings, ensuring the system remains self-supported and easy to use.
Implementation Method 1
A loading device featuring a force triangle with a slidable coupling mechanism that self-supports a nitrogen gas cylinder and lever arm
Data Source
AI summary
A loading device for an exercise machine includes a lever arm and a nitrogen gas compression spring in a force triangle that provides easy adjustment of the resistive load presented to a user. The nitrogen gas compression spring and the selected portion of the lever arm comprise two legs of the force triangle, with a slidable coupling selectively interconnecting the nitrogen gas compression spring with the lever arm at adjustment points on the lever arm. Both the nitrogen gas compression spring and the lever arm are pivotally mounted on a rigid member, with the distances between their pivots forming the third leg of the force triangle. The nitrogen gas compression spring exhibits a high resistance, a flat spring rate and is of rigid construction so that the lever arm and nitrogen gas compression spring are self-supported at all times. The nitrogen gas compression spring is coupled to the slidable coupling to produce a slight torque preload to maintain the contact orientation of the slidable coupling and the lever arm the same throughout the excursion of the lever arm for all force loadings.