Cam-Driven Contact Operating Mechanism to Prevent Opening Bounce
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Solution Overview
Problem
Existing operating mechanisms for contacts, such as vacuum interrupters, experience undesired bouncing and sparking due to high-speed movement from the closed to open position, which is exacerbated by strong contact springs.
Innovation Solution
The operating mechanism incorporates a cam profile design with a concave-up opening section that controls the movement of the cam follower, utilizing a pretensioned closing spring to counteract bouncing by counter-rotating the cam and damping the opening movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the strength of the contact spring is increased to achieve quick opening of the contact, then the opening speed is improved, but the operating rod bounces back with high speed causing undesired sparking
Solution Approach 1:
The cam profile is designed with a specific opening section that applies preliminary anti-action to counteract the bouncing tendency of the operating rod. The cam follower interacts with the cam surface to dampen the high-speed movement and prevent the operating rod from bouncing back, thereby eliminating undesired sparking while maintaining quick opening speed.
2Stability of the object's composition
If the closing spring is pretensioned to counteract bouncing, then the stability is improved, but additional force is required to rotate the cam shaft
Solution Approach 1:
The closing spring is designed with dynamic pretension that varies during operation. The spring provides increased counteracting force when bouncing is likely to occur, while allowing easier rotation during normal operation. This dynamic adjustment optimizes both stability during opening and the force required to rotate the cam shaft.
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 effectively prevents undesired movements and sparking by ensuring controlled opening and closing of contacts, maintaining reliable contact during transitions.
Implementation Method 1
a closing spring arranged between a crank arranged to the cam shaft and the base frame, wherein the closing spring relaxes when the cam follower runs over the closing section towards the opening section and wherein the closing spring has a pretension
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to an operating mechanism for operating at least one contact. The operating mechanism comprises: - an operating rod linearly guided in a base frame for connection with a contact; - a contact spring for urging the operating rod to an open position; - a rod mechanism of two links; - a cam follower arranged at the middle hinge; - a cam arranged on a cam shaft; - a cam shaft lock for locking the shaft at a rotational position where the cam follower abuts the cam at the end of a closing section; - a closing spring relaxing when the cam follower runs over the closing section towards the opening section and wherein the closing spring has a pretension, when the cam shaft is in the locked position; characterized in that the profile of the opening section (13) is designed such that the cam follower (7) follows the profile of the opening section (13) when the operating rod (3) moves from the closed position towards the open position. wherein the profile of the opening section is designed such that the cam follower follows the profile of the opening section when the operating rod moves from the closed position towards the open position.