Grill Platen Closure Sensing from Motor Back-EMF When Off

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Solution Overview

Problem

Conventional grills lack an effective method to detect the position of the platen assemblies, particularly when the motor is off, which can lead to issues such as incomplete closure, latch failure, and over-travel adjustments, affecting cooking consistency and safety.

Innovation Solution

A system that includes a motor with a control mechanism to intermittently short the motor coil, causing back EMF to flow and allowing current measurement to identify the relative position of the platen assembly, detect latch failures, and measure over-travel adjustments, even when the motor is off, utilizing a spring mechanism to bias the platen assembly and a control module with a processor to track movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor is used to detect platen closure position, then the closure detection capability is improved, but the system cannot detect position when the motor is off, leading to latch failure and incomplete closure issues

Engineering Contradiction:

Improveplaten position detection accuracyVSAvoidposition detection reliability when motor is off

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent uses the motor coil as an intermediary element to detect platen position. By temporarily shorting the motor coil and measuring back EMF-induced current, the system can detect platen position even when the motor is not actively driving the platen, thus resolving the limitation of conventional sensors that only work when the motor is active.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces conventional mechanical or active sensor-based detection systems with an electromagnetic detection method. Instead of using separate sensors that require power and active components, the system uses the motor's own electromagnetic properties (back EMF) to passively detect position, eliminating the need for additional sensing hardware.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Use of energy by moving object

If the motor is turned off after solenoid latch engagement, then energy consumption is reduced, but the system loses the ability to detect platen position and detect latch failures

Engineering Contradiction:

Improvemotor energy consumptionVSAvoidplaten position information

Core Design Contradiction:

Use of energy by moving objectVSLoss of information

Solution Approach 1:

The motor serves a dual function: it both drives the platen and detects its position. By using the motor's electromagnetic properties for detection, the system eliminates the need for separate sensing components, allowing the motor to 'self-monitor' its own operational state even when turned off.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system implements feedback by measuring the current induced in the motor coil when it is temporarily shorted. This current measurement provides feedback about the platen's position, allowing the control system to verify proper closure and detect latch failures without keeping the motor continuously powered.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If additional sensors and hardware are added to detect position when motor is off, then detection capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improveposition detection capabilityVSAvoidhardware complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The motor coil is given multiple functions: it serves as both the actuator for driving the platen and as the sensor for detecting platen position. This multi-functionality eliminates the need for separate sensing components, reducing overall system complexity and component count.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of creating a separate sensing system, the patent uses the existing motor coil's electromagnetic properties to create a detection mechanism. The back EMF effect naturally occurring in the motor coil provides the detection capability without requiring physical copies or additional sensing hardware.

Inventive Principle:

Principle #26Copying

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 precise detection of platen assembly positions, ensures smooth closure, detects latch failures, and adjusts for over-travel without requiring hardware changes or additional costs, improving cooking consistency and safety.

Implementation Method 1

shorting a motor coil of a motor operable to move an second platen assembly with respect to a first platen assembly so that back EMF causes current to flow in the motor coil in response to mechanical movement of the upper platen assembly

Methodology Applied

Scientific EffectBack EMF: Electromagnetic Induction

Data Source

PatentUS20250009172A1Grill system and method for detecting movement when motor is "off"

Publication Date: 2025.01.09 TAYLOR COMMERCIAL FOODSERVICE LLC

AI summary

A grill including a first platen assembly, a second platen assembly movable with respect to the first platen assembly, a motor operable to move the second platen assembly with respect to the first platen assembly, and a control operable to measure movement of the second platen assembly with respect to the first platen assembly when the motor is off.