Locking Pulley Movable Cheek Shape Coupling
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Solution Overview
Problem
Existing locking pulleys for ropes in climbing harnesses can accidentally open during use due to rotation or translation of the movable cheek, leading to loss of control and braking, and lack user feedback for complete closure.
Innovation Solution
A locking pulley design featuring a cylindrical contrast bushing and a rotatable locking cam with a return spring and traction means, where the movable cheek is rotatable and connected to a fixed cheek via a shape coupling and undercut, providing a secure locking mechanism with audible feedback upon closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the movable cheek is made rotatable to allow rope insertion and control, then the ease of operation is improved, but the reliability deteriorates due to risk of accidental opening
Solution Approach 1:
The patent applies preliminary anti-action by designing a retention mechanism that preemptively prevents accidental opening of the movable cheek. The retention element engages with a corresponding feature on the movable cheek to counteract any unintended rotational or translational movements, thereby maintaining reliable rope locking while preserving operational functionality.
2Reliability
If safety devices are added to prevent rotation and translation of the movable cheek, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the retention function with the existing movable cheek structure by integrating a retention element that combines rotational and translational prevention capabilities into a single unified component. This integration approach maintains high reliability while minimizing the increase in device complexity by consolidating safety functions rather than adding separate independent mechanisms.
3Reliability
If the movable cheek is designed with shape coupling and undercut for secure locking, then the reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs asymmetry in the design of the shape coupling and undercut features on the movable cheek. The asymmetric geometry creates a natural locking configuration where the shape coupling engages with its counterpart in a specific orientation, providing reliable locking while allowing for reasonable manufacturing tolerances. The asymmetric design ensures proper engagement without requiring extremely tight precision controls.
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
Prevents accidental opening by requiring intentional user action to disengage the movable cheek, ensuring secure rope locking with a distinct audible 'click' confirming complete closure.
Implementation Method 1
a return spring configured so as to rotate the locking cam towards the contrast bushing
Implementation Method 2
The movable cheek (40) and the fixed cheek (36) are shape coupled to each other in such a way as to provide a distinct audible feedback upon closure of the movable cheek (40)
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A locking pulley (4) for ropes comprising a contrast bushing (8), cylindrical with respect to an axial direction (X-X), a pulley (12) provided with a rotatable locking cam (16), wherein the contrast bushing (8) and the locking cam (16) identify a channel (24) of variable width, the locking cam (16) being provided with a return spring (28) which influences the approach to the contrast bushing (8) and traction means (32) with which a user may move it away from the contrast bushing (8). The contrast bushing (8) and the pulley (12) are mechanically connected to each other by means of a fixed cheek (36) and a movable cheek (40), wherein the movable cheek (40) is integral with the pulley (12) and is rotatable around a rotation axis parallel to said axial direction (X-X), from an opening configuration adapted to allow the insertion of a rope, in which said channel (24) is maximum, to a closing configuration adapted to allow the locking of the rope in which said channel (24) is minimum. The contrast bushing (8) comprises a peripheral groove (44) axially delimited by an end edge (48) directly facing the movable cheek (40), wherein the movable cheek (40) comprises a coupling portion (52) with a "C" counter-shape with respect to said peripheral groove (44) so as to make a shape coupling with the peripheral groove (44) and an undercut in the axial direction (X-X). Advantageously, said coupling portion (52) comprises a tooth (56) that makes a stop against the end edge (48) of the contrast bushing (8) when the movable cheek (40) is in the closed position.