Low-profile catenary hanger with keystone clamping
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Solution Overview
Problem
Existing catenary hangers for overhead contact systems face challenges in achieving a low-profile configuration that allows the trolley contact wire to rise freely in response to a current collector, while maintaining electrical integrity and preventing arcing and wear due to rigid or inflexible designs.
Innovation Solution
A low-profile catenary hanger design featuring a wire clamping assembly with keystone-shaped projections and slots, and a wire corral assembly that allows the messenger wire to move freely, enabling the trolley contact wire to rise without lifting the messenger wire, and incorporating insulating materials to prevent arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid connection is used at the messenger wire, then the structure is stable and strong, but the trolley contact wire cannot lift freely causing stiffness and arcing
Solution Approach 1:
The hanger is divided into two separate clamps: a first clamp that rigidly connects to the messenger wire, and a second clamp that loosely connects to the trolley contact wire. These clamps are connected by a flexible wire, creating segmented connections that resolve the contradiction between structural strength and wire lift freedom.
Solution Approach 2:
The flexible wire connection between the clamps allows the system to transition from a static rigid structure to a dynamic system where the trolley contact wire can lift freely during current collector passage while maintaining overall structural integrity through the rigid messenger wire connection.
2Ease of operation
If flexible wire hangers are used, then the trolley contact wire can lift freely, but the vertical clearance is limited by the clamp height
Solution Approach 1:
The flexible wire acts as a thin, adaptable connection element that allows the hanger to achieve a low-profile configuration while still permitting the trolley contact wire to lift freely. The flexible wire's ability to bend and deform enables vertical clearance reduction without sacrificing wire lift freedom.
3Reliability
If copper alloy hangers are used, then electrical conductivity is good, but arcing occurs and causes wire damage
Solution Approach 1:
The flexible wire serves as an intermediary element between the messenger wire and trolley contact wire that reduces direct electrical contact and arcing. By allowing the trolley contact wire to lift freely during current collector passage, the flexible wire minimizes arcing events that would otherwise damage the wires, while still maintaining electrical connectivity through the hanger system.
Data Source
AI summary
A low-profile catenary hanger, catenary wire system, and a method for supporting an electrical contact wire in relation to a messenger wire wherein a wire clamping assembly clamps about the contact wire, and a wire corral assembly is fixed to the clamping assembly. The corral assembly defines an adjustable reception corral through which the messenger wire is received without fastening so that the contact wire can rise without a consequent lifting of the messenger wire. The clamping assembly has a first clamping member with a keystone-shaped projection and a second clamping member with a keystone-shaped slot that can slidably receive the keystone-shaped projection to fix the clamping members together by operation of a setscrew. The clamping members together define a wire reception volume, and each clamping member has an engaging tooth whereby a contact wire with opposed longitudinal grooves can be clamped and retained by the clamping assembly.