Multimeter Input Connection Locking Mechanism
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Solution Overview
Problem
Existing multimeters lack an efficient and compact blocking mechanism to prevent false connections and ensure secure engagement of input connections based on selected measured variables, often resulting in unnecessary complexity and accessibility of the ground connection.
Innovation Solution
A pivotable angle lever locking device is introduced, which is mounted at its apex and aligns its end areas with input connections to block specific sockets, featuring a switching projection for secure engagement with the measuring range switch, and is designed to be compact, easy to manufacture, and assembled within a waterproof housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plate-like blocking link with recesses is used to block input connections, then the blocking function is achieved, but the device complexity and size increase
Solution Approach 1:
The blocking device is divided into a rotating gate element with multiple blocking positions and a separate star-shaped switching projection. The gate can be positioned in different angular locations to block different input connections, while the switching projection engages with corresponding recesses in the measuring range switch. This segmentation allows a single compact component to perform blocking for multiple measured variables without requiring a large plate-like structure with multiple recesses.
Solution Approach 2:
The blocking gate is designed as a rotatable element that can dynamically change its blocking position based on the measuring range switch setting. Instead of a static plate with fixed recesses, the gate rotates to align blocking protrusions with specific input connections. This dynamic positioning mechanism reduces the overall device complexity while maintaining reliable blocking functionality across multiple measured variables.
2Device complexity
If a compact blocking device is used, then the device size is reduced, but the engagement stability with measuring range switch may be compromised
Solution Approach 1:
The switching projection is designed with an asymmetric star shape featuring protrusions and recesses at specific angular intervals. This asymmetric geometry ensures that the projection can only engage with the measuring range switch in specific predetermined positions, providing stable and reliable engagement. The asymmetric design prevents accidental disengagement while maintaining a compact structure, as the geometric constraints inherently secure the blocking gate in the correct position.
3Adaptability or versatility
If multiple input connections are blocked by a single blocking device, then the device versatility is improved, but the blocking mechanism complexity increases
Solution Approach 1:
The blocking gate is designed as a universal component that can block multiple different input connections by rotating to different angular positions. A single gate structure with multiple blocking protrusions can correspond to different measured variables (DC voltage, AC voltage, current, resistance) by engaging with the star-shaped switching projection at different orientations. This multi-functional design allows one blocking device to replace what would otherwise require multiple separate blocking mechanisms, thereby improving versatility without proportionally increasing complexity.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The multimeter has a housing (2), and input connections (6) designed as slide-on receptacles, where the connections are provided for connecting measuring lines. A measuring range selector switch (7) is brought in a switching position, and a mechanically-operating locking device (8) is coupled with the switch. The switch permits a locking of the connections, such that a contacting of the connections takes place. The locking device is designed according to the type of an angle lever (10), where an end area of the lever is brought into a position that is aligned with the connections.