Weight-Adjustable Dumbbell Rack-and-Gear Self-Locking Assembly
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Solution Overview
Problem
Conventional weight-adjustable dumbbells have complex manufacturing processes due to high precision requirements for cam structures, leading to increased production costs and lack a self-locking mechanism to prevent plate detachment during use.
Innovation Solution
A weight-adjustable dumbbell design featuring a handle with fixing plates, sliding slots, adjusting assemblies with a driving mechanism and limiting assembly, including a rack, gear, snapping hooks, and a limiting ring for self-locking, allowing quick weight selection and plate retention without high precision manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cam structures with different contours are used to enable weight adjustment, then the dumbbell can be adjusted to different weights, but the manufacturing precision requirements increase significantly and production cost increases
Solution Approach 1:
The weight adjustment mechanism is segmented into standardized components: a rack with uniformly spaced teeth and a gear with fixed contour. Instead of requiring precise custom contours for each weight setting, the system divides the adjustment function into discrete, repeatable segments (teeth positions) that can be manufactured with standard precision, thereby reducing manufacturing complexity while maintaining versatility.
Solution Approach 2:
The invention changes the parameter of the adjustment mechanism from variable contour shapes (requiring high precision) to variable engagement positions between standardized gear and rack components. By changing from contour-based adjustment to position-based adjustment with uniform tooth spacing, the manufacturing precision requirement is significantly reduced while preserving the weight adjustment capability.
2Ease of operation
If conventional cam structures are used for weight adjustment, then the dumbbell can be adjusted easily, but the structure lacks self-locking function and connection stability is compromised
Solution Approach 1:
A spring component is introduced as an intermediary element between the gear and the dumbbell plate. The spring provides continuous contact force that enables easy adjustment by allowing the gear to engage and disengage smoothly from the rack teeth, while simultaneously providing a locking effect that prevents unintended plate detachment during use, thus resolving the contradiction between ease of operation and reliability.
3Stability of the object's composition
If high precision cam structures are manufactured, then the connection stability of dumbbell plates can be improved, but the production cost increases greatly
Solution Approach 1:
Instead of manufacturing unique high-precision cam contours for each weight setting, the invention uses a copied, repeating pattern of uniform teeth on the rack and a single standardized gear contour. This copying approach allows the same geometric pattern to be reproduced multiple times with standard manufacturing tolerances, significantly reducing both manufacturing complexity and cost while maintaining connection stability through proper engagement geometry.
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 quick weight adjustment with a self-locking function to prevent plate detachment, simplifies manufacturing, and significantly reduces production costs while maintaining structural stability.
Implementation Method 1
the gear is sleeved on the rotating shaft, and the gear is meshed with the rack
Implementation Method 2
the rack is connected to the hanging rod; the gear is meshed with the rack
Implementation Method 3
the limiting assembly is fixedly connected to the shell and matched with the driving mechanism to self-lock the driving mechanism
Data Source
AI summary
A weight-adjustable dumbbell includes: a handle, two ends of the handle respectively provided with a fixing plate; a plurality of dumbbell plates, respectively arranged sequentially along the fixing plate and movably connected to each other; a pair of first sliding slots, disposed on each of the plurality of dumbbell plates, and penetrating through each of the plurality of dumbbell plates; a pair of second sliding slots, disposed on each of the fixing plate and corresponding to the first sliding slots; and a pair of adjusting assemblies, where two ends of each of the adjusting assemblies are respectively connected to the two fixing plates and respectively corresponding to the two first sliding slots of two of the plurality of dumbbell plates.