Endless Cable Winch Braking Mechanism for Wind Service Lifts
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Solution Overview
Problem
Existing endless cable winches for service lifts, particularly in wind power plants, cause abrupt braking of safety cables during working cable failures, leading to high loads and significant physical and psychological stress on personnel.
Innovation Solution
The implementation of a braking system with a ratchet wheel and pawl mechanism that engages at a predetermined speed, reducing braking acceleration from approximately 3-5 g to 2 g, and incorporating a friction brake with a bronze and steel alloy configuration, along with a conical design, to achieve smoother and safer braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism with a braking cam is used to brake the safety cable abruptly, then the braking action is effective and reliable, but the braking acceleration becomes too high (3-5 g) causing excessive load on the safety cable and stress on personnel
Solution Approach 1:
The patent introduces a friction brake as an intermediary braking mechanism between the safety cable and the arresting device. This friction brake gradually engages to provide controlled braking force, preventing direct abrupt stopping. The friction brake acts as a mediator that transforms the high-energy braking action into a controlled friction-based deceleration process, reducing braking acceleration from 3-5 g to approximately 2 g while maintaining reliable safety braking functionality
2Object-affected harmful factors
If a friction brake is used to reduce braking acceleration to approximately 2 g, then the load on the safety cable and stress on personnel is reduced, but the braking force must be carefully controlled to maintain effectiveness
Solution Approach 1:
The patent applies parameter changes by adjusting the friction characteristics of the brake system. The friction brake uses a cone angle of approximately 4° to 10° and specific friction material pairings (bronze alloy and steel alloy) to control the braking force. By optimizing these parameters, the system achieves the desired braking acceleration of approximately 2 g while maintaining sufficient braking effectiveness to safely stop the safety cable during failure conditions
3Manufacturing precision
If the pawl is preloaded against the ratchet wheel to enable blocking at predetermined speed, then the blocking speed can be finely adjusted, but the mechanism becomes more complex
Solution Approach 1:
The patent uses parameter changes to achieve adjustable blocking speed through the pawl mechanism. The preload force of the pawl spring can be adjusted to change the speed at which the pawl engages the ratchet wheel teeth. This allows fine adjustment of the blocking speed parameter while using a relatively simple mechanical pawl-ratchet system, avoiding the need for complex electronic control systems
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
This solution results in reduced loading on the safety cable and decreased physical and psychological stress on personnel, while ensuring effective braking, with the ability to finely adjust the blocking speed and activate the arresting device manually or automatically.
Implementation Method 1
Since the brake is configured as a friction brake, there is a smooth braking operation which is still effective
Data Source
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AI summary
Disclosed is an endless cable winch, in particular for a service lift, in particular for wind power plants, having a working cable (28) and having a safety cable (16), having a driving cable pulley (58) around at least a part of which the working cable (28) is wrapped, having a drive for driving the driving cable pulley (58), and having a safety device for the safety cable (16), which safety device has a non-driven cable pulley (68), which is rotatably mounted in a housing (54) and around at least a part of which the safety cable (16) is wrapped, and also has an arresting device (31) which is coupled via a brake (71) to the cable pulley (68) and which blocks, and brakes the safety cable (16) by means of the brake (71), at a predetermined speed of the safety cable (16) at least in one direction.