Charging Assembly Over Rotation Control via Catchment Interlock
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Solution Overview
Problem
Charging assemblies in electrical switching apparatus, such as circuit breakers, face issues with cam shaft over-rotation due to wear or damage of impact surfaces and catchment components, leading to ineffective operation and potential damage over time.
Innovation Solution
A charging assembly with a catchment that includes a pivotably coupled cam shaft, a cast member with a projection, and a catchment with an impact surface and protrusion, which cooperates to resist over-rotation of the cam shaft and maintain a desired relationship with the cams, preventing glancing collisions and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the catchment is structured to cooperate with the cam to resist over rotation of the cam shaft, then over rotation is prevented, but the impact surface and catchment surface can still become worn or damaged after extended use, reducing effectiveness
Solution Approach 1:
The patent introduces a resilient member (such as a spring or elastomeric element) between the catchment's impact surface and the cam shaft. This resilient member acts as a cushion that absorbs impact forces during normal operation and particularly during over-rotation events, preventing direct metal-to-metal contact. The cushioning effect reduces wear and damage to both the impact surface and catchment surface, thereby extending their service life while maintaining reliable over-rotation prevention.
2Productivity
If the cam shaft is allowed to rotate freely during charging, then the stored energy mechanism can be charged efficiently, but the cam shaft can rotate too far and interfere with the discharge of the spring
Solution Approach 1:
The patent employs a catchment mechanism that preliminarily counteracts the cam shaft's rotation before over-rotation can occur. The catchment, through its impact surface and the resilient member, applies a restraining force to the cam shaft during the charging process. This preliminary anti-action prevents the cam shaft from rotating beyond the desired limit, ensuring that the stored energy mechanism can discharge completely without interference, while still allowing efficient charging within the safe rotation range.
3Strength
If the catchment and cam surfaces are made durable, then wear resistance is improved, but the complexity of the charging assembly increases
Solution Approach 1:
The patent introduces a resilient member as an intermediary element between the catchment's impact surface and the cam shaft. This intermediary component serves multiple functions: it cushions impact forces to reduce wear on the metal surfaces, maintains reliable over-rotation prevention, and does so without significantly increasing overall system complexity. The resilient member is a simple, compact component that integrates easily into the existing charging assembly structure.
Data Source
Figure 1A~1B
Figure 2
Figure 3~4
AI summary
A charging assembly (200) is provided for an electrical switching apparatus, such as a circuit breaker (102). The circuit breaker (102) includes a housing (104), separable contacts (106), and an operating mechanism (108) for opening and closing the separable contacts (106). The charging assembly (200) includes a stored energy mechanism, such as a closing spring (204), which is movable between charged and discharged positions. A cast member (218) is coupled to the closing spring (204) and moves therewith. The cast member (218) includes a projection (220). A cam shaft (208) is pivotably coupled to the housing (104), and includes a number of cams (210,212). A catchment (214), which is also pivotably coupled to the housing (104), includes an impact surface (224) and a protrusion (226). The impact surface (224) cooperates with a corresponding one of the cams (212) to resist over rotation of the cam shaft (208). The protrusion (226) of the catchment (214) cooperates with the projection (220) of the cast member (218) to maintain the desired relationship between the catchment (214) and the cam (212).