Lever-Arm Cover Removal Switch for Utility Meters

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Solution Overview

Problem

Electronic utility meters lack effective tamper detection mechanisms that do not rely on mechanical seals, as these may not provide adequate protection, especially for remote-read meters where unauthorized access can go unnoticed.

Innovation Solution

A meter cover with an inward extending cam that engages a plunger of a switch, causing a change in signal when the cover is removed, allowing a processing circuit to detect the tamper event without relying on mechanical seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical seals are used to detect cover removal, then tamper detection capability is improved, but the system becomes inadequate for electronic meters with remote reading capabilities

Engineering Contradiction:

Improvetamper detection capabilityVSAvoidcompatibility with remote-read electronic meters

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the purely mechanical seal system with an electronic switch system that includes a cam, plunger, and switch element. This electronic mechanism can detect cover removal and communicate the status remotely, making it suitable for electronic meters with remote reading capabilities while maintaining reliable tamper detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the meter cover is made difficult to open, then protection against unauthorized access is improved, but authorized technicians cannot access the cover when needed

Engineering Contradiction:

Improveprotection against unauthorized accessVSAvoidaccessibility for authorized technicians

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The system provides self-monitoring capability through the cam-plunger-switch mechanism that automatically detects and reports cover removal status. This eliminates the need for physical inspection of mechanical seals by technicians, allowing them to access meters when authorized while the system continuously monitors for unauthorized access.

Inventive Principle:

Principle #25Self-service

3Productivity

If remote reading is implemented, then operational efficiency is improved, but opportunity for physical inspection of tamper indicators is lost

Engineering Contradiction:

Improveoperational efficiencyVSAvoidloss of physical inspection opportunity

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The electronic switch system replaces the mechanical seal indicator that required physical inspection. The switch element electronically detects cover removal and can communicate this status remotely, maintaining operational efficiency while eliminating the need for physical inspection of tamper indicators.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If a cam mechanism is used to engage the plunger, then the switch position changes reliably with cover removal, but the device complexity increases

Engineering Contradiction:

Improveswitch position detection accuracyVSAvoidmechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cam mechanism uses a curved surface that rotates or moves to engage and disengage the plunger. This curved geometry provides reliable mechanical advantage and ensures positive engagement/disenagement of the switch element with cover removal, achieving reliable detection while keeping the mechanism relatively simple through geometric design.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

Enables timely detection and reporting of unauthorized cover removal events, even in remote-read scenarios, reducing the risk of tampering and revenue loss by using a signal change mechanism integrated into the meter's electronic components.

Implementation Method 1

The lever arm engages a spring that biases the level arm toward the second arm position

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The cam engages the plunger to hold the plunger in the first plunger position when the meter cover is installed on a meter base

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentUS10488440B2Cover removal switch having lever-arm

Publication Date: 2019.11.26 LANDIS & GYR LLC

AI summary

A meter cover removal detection arrangement includes a switch element, a pivoting lever arm, a meter cover and a plunger. The switch element has first and second positions, and conducts electricity between first and second contacts in only one of the first position and the second position. The pivoting lever arm has two arm positions, and is operably coupled to cause the switch element to be in the second position when the lever arm is in a second arm position. The lever arm engages a spring that biases the level arm toward the second arm position. The meter cover has an inward extending cam. The plunger has first and second plunger positions, and is operably coupled to hold the pivoting lever arm in the first arm position when the plunger is in the first plunger position. The cam engages the plunger to hold the plunger in the first plunger position when the meter cover is installed on a meter base. The cam is disengaged from the plunger when the meter cover is removed.