Rotary Electronic Lockbox With Optical Position Sensing

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Solution Overview

Problem

Conventional electronic lockboxes with linear actuators face reliability issues due to the use of mechanical sensors like linear potentiometers, which degrade over time, and require energy-consuming spring cycles for unlocking, leading to inefficiencies and reduced durability.

Innovation Solution

An electronic lockbox with a rotary actuator using non-contact sensors, such as optical sensors, to detect multiple positions, reducing wear and energy consumption by employing a movable indicator disk with windows to interact with photosensors and a motor-driven mechanism for precise locking and unlocking states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If linear actuators with mechanical sensors (linear potentiometers) are used, then the lockbox can achieve locking and unlocking functions, but the sensors degrade over time reducing reliability

Engineering Contradiction:

Improvesensor durabilityVSAvoidsensor service life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces mechanical contact sensors (linear potentiometers) with non-contact optical sensors that detect the position of an indicator disk through optical windows. This substitution eliminates mechanical wear on sensing components while maintaining the ability to detect actuator position for locking and unlocking states.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an indicator disk with optical windows as an intermediary element between the actuator and the optical sensors. The indicator disk translates mechanical actuator movement into optical signal variations that the sensors can detect without physical contact, thereby extending system reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If spring cycles are used for unlocking, then the lockbox can achieve the unlocking function, but it consumes excessive energy

Engineering Contradiction:

Improveunlocking functionVSAvoidenergy consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent replaces the spring-based mechanical unlocking mechanism with an electronically controlled rotary actuator driven by a motor. The actuator receives electrical commands to rotate to specific positions (0°, 120°, 240°) corresponding to different locking states, eliminating the need for energy-intensive spring compression and release cycles.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a state-machine control system that transitions the actuator between discrete angular positions (0°, 120°, 240°) based on operational requirements. This periodic positioning approach allows the system to maintain stable states without continuous energy consumption, only activating the motor when state transitions are needed.

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If multiple mechanical components are used for locking states, then the lockbox can achieve multiple locking functions, but the device complexity increases

Engineering Contradiction:

Improvemultiple locking statesVSAvoidmechanical component count

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs a single rotary actuator that performs multiple locking functions by rotating to different angular positions. The same actuator mechanism controls both the key bin latch and shackle release through position-dependent optical sensor detection, eliminating the need for separate mechanical actuators for each locking function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the detection of multiple locking states into a single optical sensing system that monitors the position of one indicator disk. The optical sensors detect which angular position the actuator is in, thereby determining whether the key bin is locked, the shackle is released, or both operations are complete, merging multiple detection functions into one system.

Inventive Principle:

Principle #5Merging (Combining)

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 rotary actuator design enhances durability and energy efficiency by minimizing sensor wear and reducing energy use, while providing robust security through tamper-resistant mechanisms.

Implementation Method 1

at least one photosensor that detects at least a portion of the electromagnetic energy that is emitted by the at least one LED

Methodology Applied

Scientific EffectElectromagnetic energy detection: Photoelectric Effect

Data Source

PatentUS12480333B2Electronic lockbox

Publication Date: 2025.11.25 SENTRILOCK LLC

AI summary

An electronic lockbox uses a rotary actuator with multiple positions to achieve multiple locking states. Multiple positions of the actuator are detected, using optical sensors. The locking mechanism includes an outer sleeve and an inner cylindrical barrel that are coupled with torsion springs. The lockbox has a shackle and a key bin that are retained by the inner barrel when in the locked state, and the barrel can be rotated to either release the shackle or to release the key bin that typically holds a building's key.