Weight-Adjustable Dumbbell Cam Locking for Secure One-Handed Selection
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Solution Overview
Problem
Existing weight-adjustable dumbbells face challenges in convenience and safety during weight adjustment, often requiring labor-intensive two-handed operation and risking plate detachment during use.
Innovation Solution
A weight-adjustable dumbbell design featuring a handle-driven cam structure with a gear ring assembly and elastic snapping pins, allowing single-handed operation and ensuring secure weight adjustments by providing tactile feedback and preventing plate detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a scale rotating plate drives a driving shaft to rotate for weight adjustment, then the handle does not rotate and single-handed operation is enabled, but the structure becomes more complex requiring additional transmission components
Solution Approach 1:
The patent combines the handle rotation function with the driving shaft rotation function into a single integrated component. The handle is directly coupled to the driving shaft, eliminating the need for separate transmission components like belts or gears. This merging reduces structural complexity while maintaining the ability to adjust weight with one hand, as the handle's rotation directly drives the cam structures to select different dumbbell plates.
2Ease of operation
If the handle directly drives the cam structure to rotate through a driving plate, then torque requirements are reduced and operation is more convenient, but the positioning shaft must remain stationary requiring a control device
Solution Approach 1:
The patent segments the rotation function between two independent components: the handle/d driving shaft assembly that rotates freely to enable easy operation, and the positioning shaft that remains stationary to provide stable support for the cam structures. A control device bridges these segments, allowing the rotating driving shaft to selectively engage different cam structures on the stationary positioning shaft. This segmentation reduces torque requirements on the positioning shaft while maintaining operational convenience.
3Reliability
If the gear ring assembly with elastic snapping pins is used to control cam structure rotation, then tactile feedback is provided and plate detachment is prevented, but the device complexity increases
Solution Approach 1:
The patent incorporates elastic snapping pins that engage with corresponding slots on the cam structures to provide tactile feedback during rotation. As the driving shaft rotates and selects different cam structures, the snapping pins click into place at discrete angular positions, giving the user clear sensory feedback that a specific weight setting has been selected. This feedback mechanism ensures reliable engagement and prevents accidental detachment of dumbbell plates, enhancing overall system reliability.
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
Enhances user convenience by reducing torque requirements and ensuring safe, precise weight adjustments with clear feedback, preventing accidental plate detachment.
Implementation Method 1
a spring-control block, disposed at a lower end of the gear ring assembly, for locking the gear ring assembly
Implementation Method 2
two ends of the handle are respectively provided with a plurality of cam structures, a driving plate is disposed between the handle and the cam structures, and the handle drives the plurality of cam structures to rotate on the positioning shaft through the driving plate
Data Source
AI summary
A weight-adjustable dumbbell includes a plurality of dumbbell plates; abase for holding the dumbbell plates; a positioning shaft; a handle movably sleeved on the positioning shaft; a plurality of cam structures disposed on two ends of the handle respectively; and a driving plate disposed between the handle and the cam structures, where the handle drives the plurality of cam structures to rotate on the positioning shaft through the driving plate; where two ends of the positioning shaft are respectively provided with a control device, the control device is connected to the cam structure to control the cam structure rotating relatively with the dumbbell plates.