Wire Rope Hoist Limiter With Sliding Weight Stop Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wire rope hoist limiters require specific types of roping and structure adaptations, lacking backup in case of failure and are not easily mountable on different types of hoists.
Innovation Solution
A limiter device with a sliding weight and flexible fastener that can be fastened to various wire rope hoists without disassembly, using mechanical or electromechanical detection to stop the hoist when the load reaches a predetermined height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wire rope hoists operate in unison to increase productivity, then material handling efficiency is improved, but synchronization errors cause the ropes to cross and create dangerous situations
Solution Approach 1:
The patent applies preliminary action by providing limit switches that are pre-positioned at specific heights on the hoistway wall before operation begins. These switches are predetermined to activate at critical positions, preventing synchronization errors before they can cause dangerous rope crossing conditions. The system proactively monitors and limits hoist travel positions rather than reacting to problems after they occur.
2Reliability
If limit switches are mounted on the hoist car or hook assembly, then synchronization can be monitored, but the switches are subject to damaging shocks and vibrations
Solution Approach 1:
The patent applies segmentation by separating the limit switch mounting from the moving hoist car assembly. The switches are mounted independently on the stationary hoistway wall structure, dividing the monitoring function from the moving components. This segmentation isolates the sensitive electrical switches from the mechanical shocks and vibrations generated during hoist operation, while still enabling synchronization monitoring through the wall-mounted position detection.
3Strength
If limit switches are mounted on the hoistway wall, then they are protected from shocks and vibrations, but improper positioning can cause hoist car collisions
Solution Approach 1:
The patent applies preliminary action by establishing precise predetermined positioning criteria for wall-mounted limit switches during the design and installation phase. The switches are positioned at specific heights and locations on the hoistway wall before operation begins, with careful attention to ensuring correct spacing and alignment. This preliminary precision in positioning prevents hoist car collisions while maintaining the protective benefits of wall mounting.
4Reliability
If the hoist car is stopped by impacting a fixed stop, then the limiter function is achieved, but excessive impact forces damage the hoist car
Solution Approach 1:
The patent applies beforehand cushioning by using spring-loaded or flexible limiter mechanisms that engage before the hoist car reaches its maximum travel position. These cushioning elements gradually decelerate the hoist car as it approaches the limit, absorbing kinetic energy and reducing the impact force compared to rigid fixed stops. The cushioning action occurs in advance of the final stop position, protecting the hoist car from excessive forces while still achieving reliable position limitation.
Data Source
Figure 1a~1b
Figure 1c~2
Figure 3
AI summary
A wire rope hoist limiter device (100), comprising: a fastener (110) arranged to be fastened around the wire rope of the wire rope hoist; a sliding weight (120) arranged to slide along the wire rope (10) of the wire rope hoist towards the fastener (110); and a detector (150, 160') arranged to be fastened to the wire rope of the wire rope hoist by means of the fastener (110). The detector (150, 160') is arranged to detect the sliding weight (120) at a certain distance from the fastener (110) and to give a stop signal for the wire rope hoist in response.