Over-Center Cam Locking Mechanism for Exercise Machine Adjustment
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Solution Overview
Problem
Conventional indoor cycling bicycles lack a convenient and easy way to rapidly and predictably change resistance and adjust seat and handlebar heights to accommodate different riders during exercise.
Innovation Solution
A multifunction brake actuator and pop-pin assembly are introduced, allowing for fine and coarse adjustment of braking resistance and easy adjustment of seat and handlebar heights through a locking mechanism with an over-center cam mechanism, enabling quick and secure positioning of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional locking mechanisms are used for seat and handlebar adjustment, then the structure is simple, but the adjustment speed and reliability are insufficient
Solution Approach 1:
The locking mechanism uses a dynamic cam-based system where the cam transitions between locked and unlocked states through rotational movement. The cam profile creates dynamic force multiplication during the locking action, enabling rapid adjustment while maintaining structural reliability. The spring-loaded follower dynamically responds to cam rotation to engage or disengage locking pins.
Solution Approach 2:
The adjustment system is segmented into independent modules: the cam mechanism for rapid locking/unlocking, the spring-loaded follower for force application, and the positioning pins for discrete height settings. This segmentation allows each component to be optimized for its specific function while working together to achieve fast and reliable adjustment.
2Productivity
If rapid resistance change is implemented, then training effectiveness improves, but mechanism complexity increases
Solution Approach 1:
The brake actuator merges multiple functions into a single integrated mechanism: the cam-based lever simultaneously controls brake pad positioning and resistance level selection. The same cam rotation that locks the brake arm in place also engages the resistance mechanism, eliminating the need for separate controls and reducing overall system complexity despite the rapid adjustment capability.
Solution Approach 2:
The cam mechanism serves multiple purposes: it locks the brake arm at selected positions, adjusts resistance levels, and maintains constant pressure on the brake pad through the spring-loaded follower. This multi-functionality allows rapid resistance changes without requiring additional separate mechanisms for each function.
3Reliability
If secure locking is achieved, then positioning reliability improves, but adjustment ease decreases
Solution Approach 1:
The cam profile utilizes curved geometry to create a mechanical advantage during the locking action. The cam's rounded profile allows smooth rotational movement while generating concentrated locking forces at specific points. The curved path of the spring-loaded follower along the cam surface ensures gradual engagement and secure locking without requiring excessive manual force.
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 users to easily and securely adjust resistance levels and seat/handlebar positions, enhancing user comfort and fitness training effectiveness by accommodating various rider sizes and preferences.
Implementation Method 1
a locking mechanism with an over-center cam mechanism, enabling quick and secure positioning of components
Implementation Method 2
the lever pivotal between a first position where the drive shaft is driven toward the first member to fix the first member relative to the second member
Implementation Method 3
the tongue (30) is spring-loaded at the vertical tube (1) facing side of the pressure piece (30)
Data Source
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AI summary
An exercise machine, such as indoor cycle, including a multi-function wheel brake actuator. A braking force is induced on a wheel, such as through eddy currents or frictionally, by finely or coarsely adjusting the brake actuator. The brake actuator may thus include a knob whereby a user may finely adjust the braking force on the wheel and a lever to actuate interval settings whereby the brake actuator provides set positions of braking resistance. The exercise machine may further include a pop-pin assembly with an over-center cam mechanism to clamp members together. The pop-pin assembly also includes a fine adjustment to adjust the clamping force. So, for example, the seat stem may be clamped to the seat tube, or the handlebar stem clamped to the head tube, with a lever actuating the over center mechanism.