Cable Trolley Friction Device Using Load-Based Cable Deflection
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Solution Overview
Problem
Existing cable trolleys with friction pads or magnets are inconsistent in controlling friction, leading to issues with speed regulation and safety, particularly for varying loads, as they either cause lighter materials or riders to get stuck or overwhelm the arrest system with excessive speed.
Innovation Solution
A cable trolley system with a housing and a friction device that includes a pulley system and an adjustable attachment mechanism, where the weight of the load causes cable deflection, providing adjustable friction based on load weight, ensuring consistent speed and safety by altering the cable's path around pulleys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction pads or magnets are used to control friction on cable trolleys, then friction can be added to the wheels or cable, but the friction control becomes inconsistent and parts wear out
Solution Approach 1:
The patent removes friction pads and magnets from the traditional trolley design, extracting the problematic friction-generating components. Instead, it uses the cable's own flexibility and the trolley's weight to create the necessary friction through cable deflection, eliminating parts that wear out and provide inconsistent friction.
Solution Approach 2:
The system uses the load's own weight to generate the required friction force. Heavier loads create greater cable deflection and thus more friction, while lighter loads create less deflection and less friction. This self-regulating mechanism eliminates the need for external friction control devices and their associated complexity.
2Speed
If friction is increased to control speed of heavier loads, then heavier materials or riders will not come into the arrest system with excessive speed, but lighter materials or riders will get stuck on the zipline
Solution Approach 1:
The friction force is made dynamic rather than static. The cable deflection and resulting friction automatically adjust based on the instantaneous load weight. As the load changes, the system dynamically adapts the friction force to maintain appropriate descent speed without getting stuck or overwhelming the arrest system.
Solution Approach 2:
The system changes the friction parameter automatically based on load conditions. Instead of using a fixed friction mechanism, the cable deflection angle and resulting friction force vary continuously with the load weight, allowing the same system to handle both light and heavy loads appropriately.
3Force
If traditional friction devices are used, then friction can be applied to the cable, but the friction does not control properly based on weight
Solution Approach 1:
The system uses the load's weight itself as the counterbalancing force that generates friction. The weight creates cable deflection, and this deflection creates the friction force that opposes motion. The friction force is directly proportional to the load weight, providing precise weight-based control without requiring external measurement or adjustment mechanisms.
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 system maintains a constant speed for all loads, preventing premature sticking or excessive force on the arrest system, ensuring safe and controlled descent by dynamically adjusting friction based on load weight.
Implementation Method 1
a friction device attached to the housing and configured to cause deflection of the cable relative to an amount of load attached to the load attachment point
Implementation Method 2
the weight of the load causes cable deflection, providing adjustable friction based on load weight
Data Source
AI summary
Apparatus, system, and methods for providing load responsive friction for a cable trolley device. An apparatus includes a housing configured to receive a cable. The housing includes a load attachment point and a friction device attached to the housing. The friction device is configured to cause deflection of the cable relative to an amount of load attached to the load attachment point.