Self-locking Abseil Device Handle Cam Mechanism
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Solution Overview
Problem
Conventional self-locking descenders for rope access technicians are not sufficiently safe due to risks of involuntary descent caused by interactions with tools, and existing solutions do not adequately reduce these risks.
Innovation Solution
A self-locking descender design where the handle moves between a storage position, a blocking position, and a descent position, with a mechanical connection to the cam that ensures the rope is automatically locked when inserted, and the handle is positioned on one side of the descender with the descent position on the opposite side, separated by at least 90°, and a spring mechanism to return the handle to the storage position, reducing the risk of accidental activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the handle is positioned close to the cam for easy operation, then the ease of operation is improved, but the risk of accidental activation by tool interactions increases
Solution Approach 1:
The patent positions the handle at a distance from the cam along the rotational path, utilizing angular separation (at least 90 degrees) as an additional spatial dimension. This dimensional arrangement ensures that tools approaching from typical directions cannot simultaneously contact both the handle and cam, thereby reducing accidental activation while preserving operational accessibility.
2Speed
If the handle is mechanically linked to the cam for direct control, then the responsiveness is improved, but the vulnerability to unintentional descent increases
Solution Approach 1:
The patent introduces an intermediary mechanical linkage system between the handle and cam, where the handle rotates independently but transmits controlled motion to the cam through a defined mechanical path. This intermediary mechanism ensures that handle rotation must overcome specific mechanical constraints, preventing unintentional cam actuation while maintaining deliberate control responsiveness.
3Ease of operation
If the handle can be easily rotated between positions, then the ease of operation is improved, but the risk of accidental position changes increases
Solution Approach 1:
The patent incorporates a spring mechanism that performs preliminary action by continuously exerting force to return the handle to its initial position. This preliminary spring force creates a stable equilibrium state, ensuring that any accidental disturbances are automatically counteracted, while deliberate user input can still easily overcome the spring force for intentional position changes.
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 design enhances safety by ensuring the rope is automatically locked during workstation operations, reducing the risk of involuntary descent and tool interactions, and provides a clear indication of correct rope installation, while the spring mechanism protects the handle and increases the security of the blocking position.
Implementation Method 1
a spring mechanism to return the handle to the storage position
Implementation Method 2
a cam which moves inside the first flange and comes into contact with the rope in order to lock it inside the descender or to modulate a friction force allowing the rope to slide inside the descender
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The self-locking rope descender (3) comprises a first flange (1) and a cam (2) mounted movably relative to the first flange (1) successively between a first position, a rope locking position (3), and a rope circulation position (3) within the first flange (1). It also comprises a handle (5) mounted movably relative to the first flange (1) successively between a storage position, a first operating position locking the rope (3), and a rope circulation position (3). A first spring is connected to the first flange (1) and to the handle (5) so as to return the handle (5) to the storage position. The cam (2) is mechanically linked to the handle (5) intermittently such that a movement of the cam (2) from the first position to its rope locking position (3) causes a movement of the handle (5) from its storage position to the first operating position.The handle (5) is not mechanically linked to the cam (2) between the first operating position blocking the rope (3) and a rope circulation position (3).