Cable Lifting Device With Inclined Guide Arm
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Solution Overview
Problem
Existing cable lifting devices, such as grapple-type and unwinding pulley systems, face challenges including difficulty in securely grasping cables, risk of damage due to collisions and stress concentration, and inefficiencies in operation, particularly when suspended from a sling for maintenance or replacement tasks on high-voltage transmission lines.
Innovation Solution
A cable lifting device comprising a pulley sheave, a bearing element for the axis of rotation, and a guide arm, along with a guide plate that automatically orients itself relative to the cable upon contact, extending the area for cable engagement and reducing the risk of damage by ensuring optimal alignment with the pulley sheave groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grapple-type lifting device is used to grab the cable, then the cable can be secured for lifting, but the device becomes too heavy and complex due to the need for sufficient material strength to resist bending during pivoting
Solution Approach 1:
The lifting device is divided into separate functional components: a pulley sheave for cable engagement, a guide arm for directional guidance, and a bearing element for rotation. This segmentation allows each component to be optimized independently, reducing overall weight while maintaining reliability.
Solution Approach 2:
The pulley sheave uses a curved, rounded surface instead of sharp edges or hooks. This curvature distributes stress evenly across the cable contact area, eliminating the need for heavy reinforcement materials while ensuring secure cable engagement without damage.
2Object-affected harmful factors
If an unwinding pulley is used for cable lifting, then the risk of cable damage is reduced due to rounded surface, but the device spins uncontrollably when suspended in air, complicating operation
Solution Approach 1:
The guide arm is designed with asymmetric geometry, extending inclined upwards at a specific angle in a plane containing the pulley axis. This asymmetric configuration creates a stable equilibrium position when suspended, preventing uncontrolled spinning while maintaining the rounded cable contact surface.
Solution Approach 2:
The guide arm is pre-positioned at an inclined angle before cable contact occurs. This preliminary geometric arrangement ensures that when the cable approaches, it is automatically guided onto the pulley groove without requiring manual adjustment or creating uncontrolled rotation.
3Ease of operation
If an unwinding pulley with guide arm is used, then cable guidance is improved, but the operational zone is restricted to a small angular sector, reducing productivity
Solution Approach 1:
The guide arm extends in three-dimensional space at an inclined angle, creating a broader spatial acceptance zone. This dimensional extension allows the cable to approach from multiple angles and positions, expanding the effective operational sector from a narrow angular range to a more comprehensive three-dimensional zone.
Data Source
AI summary
This device (34) for lifting a cable mounted on pylons, intended to be suspended from the free end of a sling (22), comprises: a pulley sheave (38); an element (40) carrying the axis of rotation of the pulley sheave (38); and an arm (42) for guiding the cable towards a groove in the pulley sheave (38), the main axis of this guide arm (42) extending inclined upwards, in a plane containing the axis of rotation of the pulley sheave (38), when the lifting device (34) is suspended from the sling (22). It further comprises a guide plate (36), extending in a plane intended to contain the sling (22), one end of which (36B) is fixed to the supporting element (40) so as to keep the plane in which the guide plate (36) extends substantially perpendicular to the plane containing the axis of rotation of the pulley sheave (38) and the axis of the guide arm (42).