Split Insulated Input Posts for High-Current Error Prevention

Solution Overview

Problem

Electrical measurement tools, such as digital multimeters, can be damaged or cause injury when test leads are connected to inappropriate input terminals based on the selected mode of operation, leading to potential damage from high currents or voltage exceeding internal fuses.

Innovation Solution

A split input terminal design with an insulating sleeve and a controller that determines the mode of operation and whether test leads are connected, triggering a nonconductive state in the circuit breaker or issuing warnings to prevent damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the digital multimeter allows test leads to be connected to any input terminal regardless of selected mode, then the device is easy to operate and versatile, but high current may flow through the device causing damage to internal components and injury to the user

Engineering Contradiction:

Improveease of operationVSAvoidhigh current damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary detection of test lead connection status at the input terminal before allowing measurement operations. The system detects whether test leads are connected to current measurement terminals before enabling voltage measurement mode, and prevents operation by displaying warning messages or blocking the measurement function until proper connection is established, thereby preventing high current damage before it can occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs feedback mechanisms where the system continuously monitors the connection status of test leads and provides real-time feedback to the user through display warnings. When improper connections are detected, the system feedbacks warning messages to guide users to correct their connections, and only allows operation when proper connections are established, thus preventing damage while maintaining ease of operation

Inventive Principle:

Principle #23Feedback

2Device complexity

If the digital multimeter uses a single input terminal for both current and voltage measurement, then the device structure is simple, but the device cannot detect improper connections and may allow damaging current flow

Engineering Contradiction:

Improvedevice structureVSAvoidconnection detection accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the input terminal into multiple distinct terminals with different functions - current measurement terminals and voltage measurement terminals. Each terminal type has specific connection requirements and the system can detect which terminal type is being used. This segmentation allows the system to detect improper connections by monitoring which terminal is connected, thereby preventing damage while maintaining relatively simple device structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary detection mechanism between the input terminals and the internal measurement circuits. This intermediary system monitors the connection status at each terminal and provides information to the control logic, enabling the system to detect improper connections and prevent damaging operations without significantly increasing overall device complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If the digital multimeter allows operation without connection detection, then the device is easy to manufacture and operate, but internal fuses may blow and internal components may be damaged

Engineering Contradiction:

Improveease of manufactureVSAvoidinternal component protection

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent implements preliminary detection of test lead connection status at the input terminal before allowing measurement operations. The system detects whether test leads are connected to current measurement terminals before enabling voltage measurement mode, and prevents operation by displaying warning messages or blocking the measurement function until proper connection is established, thereby preventing high current damage before it can occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs feedback mechanisms where the system continuously monitors the connection status of test leads and provides real-time feedback to the user through display warnings. When improper connections are detected, the system feedbacks warning messages to guide users to correct their connections, and only allows operation when proper connections are established, thus preventing damage while maintaining ease of operation

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP4493941B1Split insulated input post for electrical measurement tool

Publication Date: 2025.10.29 FLUKE CORP

Figure 1
Figure 2A~2B
Figure 2C~2D

AI summary

A device for performing electrical measurements according to the present disclosure includes a first input post that is electrically conducting, a second input post that is electrically conducting, and a sleeve that is electrically insulating and at least partially surrounds the first input post and the second input post. The sleeve includes a first rib extending in a longitudinal direction of the sleeve and a second rib extending in the longitudinal direction of the sleeve. The first rib and the second rib are constructed to separate the first input post and the second input post.