Double Break Disconnect Switch Cam Drive Mechanism
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Solution Overview
Problem
High voltage switches face challenges in rotational movement due to ice buildup and debris, requiring large forces for opening and closing, and existing mechanisms do not provide precise and adjustable operating forces, leading to operational difficulties, especially in icy conditions.
Innovation Solution
A double break disconnect switch with a novel drive mechanism using a unique cam arrangement and offset blade bearings, allowing for precise and adjustable force application during closure, with a quick release mechanism to facilitate easy operation and resistance to jamming, utilizing a roller in a slot with changing angles to manage force and torque effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional gear or cam mechanisms are used for rotational movement of the switch blade, then the switch can be operated, but large forces are required to overcome ice buildup and debris between the fixed jaws and blade assembly
Solution Approach 1:
The patent employs a dynamic cam mechanism where the cam profile changes during operation. The cam surface is designed with varying radii of curvature that provide high force multiplication during the critical phases of blade movement, allowing the mechanism to adapt its mechanical advantage dynamically rather than relying on fixed gear ratios. This enables the system to overcome variable resistance forces from ice and debris while maintaining ease of operation.
Solution Approach 2:
The invention changes the geometric parameters of the cam profile during operation. The cam surface is designed with specific radius of curvature variations that alter the mechanical advantage throughout the rotation cycle. By carefully controlling the cam geometry, the system optimizes force transmission at different stages of blade movement, reducing the overall operating force required while maintaining reliability against jamming.
2Reliability
If fixed gear teeth or rigid cam surfaces are used, then rotational movement is achieved, but the mechanism is sensitive to variations in operating conditions such as ice buildup and debris
Solution Approach 1:
The patent employs a dynamic cam mechanism where the cam profile changes during operation. The cam surface is designed with varying radii of curvature that provide high force multiplication during the critical phases of blade movement, allowing the mechanism to adapt its mechanical advantage dynamically rather than relying on fixed gear ratios. This enables the system to overcome variable resistance forces from ice and debris while maintaining ease of operation.
Solution Approach 2:
The invention changes the geometric parameters of the cam profile during operation. The cam surface is designed with specific radius of curvature variations that alter the mechanical advantage throughout the rotation cycle. By carefully controlling the cam geometry, the system optimizes force transmission at different stages of blade movement, reducing the overall operating force required while maintaining reliability against jamming.
3Ease of operation
If the switch blade rotates about its longitudinal axis to achieve contact pressure, then closing and opening is enabled, but precise and adjustable operating forces cannot be provided
Solution Approach 1:
The invention changes the geometric parameters of the cam profile during operation. The cam surface is designed with specific radius of curvature variations that alter the mechanical advantage throughout the rotation cycle. By carefully controlling the cam geometry, the system optimizes force transmission at different stages of blade movement, reducing the overall operating force required while maintaining reliability against jamming.
Solution Approach 2:
The patent incorporates a feedback mechanism through the cam-follower arrangement. The follower rides on the cam surface and automatically adjusts its position to maintain optimal contact pressure. This passive feedback system ensures that the blade receives precisely controlled forces during closing and opening operations, with the cam profile itself acting as the control element that regulates force transmission based on the blade's position and contact conditions.
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 solution enables precise and reliable closure with reduced operational force, self-regulation against increased friction, and improved resistance to jamming, ensuring easy operation even in icy conditions and maintaining performance across varying current ratings.
Implementation Method 1
A double break disconnect switch with a novel drive mechanism using a unique cam arrangement and offset blade bearings, allowing for precise and adjustable force application during closure
Implementation Method 2
the blade bearings are offset from the blade center of gravity so as to use the blade's weight to keep the blade in the position of disengagement with the break jaw contacts when the switch is opened
Implementation Method 3
utilizing a roller in a slot with changing angles to manage force and torque effectively
Data Source
AI summary
A double break disconnect switch including a bearing arrangement carrying a switch blade assembly is mounted on a drive arrangement. The switch blade assembly is rotatable longitudinally during initial opening and final closing of the switch and transversely for final opening and initial closing. The switch blade assembly is hinged for rotation about a hinge axis offset from the center of gravity of the switch blade for initial opening and for final closing. A blade bearing is provided of very small in diameter. The drive assembly uses the weight of the blade to keep the blade from rotating longitudinally and uses a cam arrangement including a roller riding in a slot of a blade drive plate that is spring loaded on one end and pivotally attached at the other end to rotate the blade longitudinally providing greater force to rotate the blade as contacts engage.