Interlocking Mechanism for Low Voltage Switching Devices
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Solution Overview
Problem
Existing interlocking mechanisms for low-voltage switching devices are prone to short-circuit faults due to friction and displacement between housings caused by repeated rotations of the cam and shaft assembly, leading to simultaneous closure of switching devices.
Innovation Solution
The interlocking mechanism addresses this by orienting the shaft perpendicular to the sliding plane, incorporating lateral locking elements on the cam, and using a curved outline to reduce friction and wear, ensuring that one switching device remains locked out when the other is closed, thereby preventing short-circuits and extending the mechanism's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cam and shaft assembly is used for interlocking switching devices, then the switching devices can be mechanically locked to prevent simultaneous closure, but friction and displacement between housings occur during repeated operations leading to short-circuit faults
Solution Approach 1:
The shaft is reoriented from a horizontal configuration to a vertical configuration, changing the dimension of rotation. This dimensional change allows the cam to rotate perpendicular to the sliding plane, eliminating friction between the cam-shaft assembly and the housings while maintaining the interlocking function through lateral locking elements that engage with the sliding bars.
2Ease of operation
If the cam rotates repeatedly during switching operations, then the interlocking mechanism can lock out one switching device when the other is closed, but the repeated rotation causes friction between the shaft-cam assembly and housings resulting in displacement
Solution Approach 1:
The harmful frictional contact between the cam-shaft assembly and the housings is eliminated by extracting the source of friction. The vertical shaft configuration removes the cam-shaft from contact with the housing surfaces, allowing repeated rotation operations without causing housing displacement or instability.
3Reliability
If the shaft is disposed perpendicular to the sliding plane, then friction and displacement are significantly reduced, but the locking elements must be precisely positioned to engage with the sliding bars
Solution Approach 1:
Lateral locking elements protruding from the cam serve as intermediaries between the rotating cam and the sliding bars. These locking elements engage with openings in the sliding bars through lateral movement, providing a reliable mechanical connection that tolerates minor positioning variations while maintaining effective interlocking.
Data Source
Figure 1~1b
Figure 2~6
Figure 3~4
AI summary
The present invention relates to an interlocking mechanism (1) for inter- locking a first and a second low voltage switching devices (200, 200'), wherein each of the switching devices (200, 200') comprises a movable contact part, a stationary contact part and, an actuating unit for operating the movable contact part in a direction and making connection or disconnection with the stationary contact part, the interlocking mechanism com- prising a first and a second housing (2, 2') connected to each other,a first and a second sliding bar (10, 10'), where in the first sliding bar (10) is arranged on the first housing (2) and connecting to the actuating unit of the first switching device (200), where in the second sliding bar (10') is arranged on the second housing (2') and connecting to the actuating unit of the second switching device(200'), and wherein a sliding plane (P) is de- fined and has a X-and Y-axis, the Y-axis being defined in the direction of motion of the actuating unit of the switching devices (200, 200') and, wherein each of the sliding bars (10, 10') are configured to slide in the Y- axis direction of the sliding plane (P), a shaft (30) disposed between the first and the second houses (2, 2'), and a cam (40) configured to be rotatable about the shaft (30) when both switching devices are in open positions. The shaft (30) is disposed to be perpendicular to the sliding plane (P) so that the shaft (30) is perpendicular to the direction of motion of the actuating unit of the switching devices. Furthermore, the cam (40) further comprises a first and a second locking element (42, 42') for blocking the first and second sliding bar (10, 10') respectively, each of the locking elements (42, 42') protruding laterally in the X-axis direction. Each of the sliding bars (10, 10') further comprises an opening (12, 12') at one end of the bar, wherein the opening (12, 12') is configured for retaining the corresponding locking element (42, 42') when the corresponding switching de- vice (200, 200') is in a closed position.