Self-locking Pulley with Cam and Spring Mechanism
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Solution Overview
Problem
Existing pulley systems are not compact enough and lack effective rope locking mechanisms, leading to variability in blocking quality due to friction dependence on rope and pulley wear.
Innovation Solution
A self-locking pulley design featuring a fixing head, a first flange with a rotating shaft, a sheave that rotates in one direction, a blocking cam that moves relative to the sheave, and a spring to exert force on the cam, along with a textured groove for enhanced friction, allowing the pulley to lock the rope effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pulley system uses friction-based rope locking, then the pulley can be simpler in design, but the locking reliability becomes variable and dependent on rope and pulley wear
Solution Approach 1:
The pulley system automatically locks the rope using the weight of the load itself. When the load descends, gravity causes the cam to rotate and engage with the toothed wheel, creating a self-locking mechanism without requiring additional active components or external power sources.
Solution Approach 2:
The patent replaces friction-based locking with a mechanical interlocking system. The cam and toothed wheel create a positive mechanical lock that engages disengages through defined mechanical interactions, eliminating dependence on friction and wear-prone surfaces.
2Reliability
If the pulley uses a cam mechanism to lock the rope, then locking reliability improves, but the device becomes more complex
Solution Approach 1:
The cam mechanism is integrated directly into the pulley body, merging the locking function with the pulley structure itself. The cam is positioned within the pulley housing and interacts with a toothed wheel that is part of the same assembly, eliminating the need for separate locking mechanisms.
Solution Approach 2:
The cam is designed to rotate dynamically in response to load weight, automatically engaging and disengaging from the toothed wheel based on the operational state. This dynamic interaction provides consistent locking performance across varying load conditions without requiring manual intervention.
3Volume of moving object
If the pulley is designed to be compact, then portability improves, but space for locking mechanisms is reduced
Solution Approach 1:
The cam mechanism is nested within the pulley housing, with the cam rotating within a dedicated chamber in the pulley body. The toothed wheel is positioned within the same compact assembly, allowing the locking mechanism to be contained within the minimal pulley structure without requiring additional external components.
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
The pulley system achieves compactness and reliable rope locking with reduced sensitivity to rope diameter variations, ensuring consistent blocking performance and minimizing friction-induced heating.
Implementation Method 1
a spring mounted to exert a force moving the locking cam towards the first sheave
Implementation Method 2
the first sheave has a textured groove, more preferably a faceted groove
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The pulley (1) comprises a mounting head (2) and a first flange (3). A first shaft (4) extends from the first flange (3). A sheave (5a) is mounted to rotate around the first shaft (4) in a single direction. A cam (7) is mounted to move away from or toward the sheave (5a). A spring (8) is mounted to exert a force moving the cam (7) toward the sheave (5a). A handle (9) is mounted on the first flange (3) to move the cam (7) between first and second positions.