Power Tool Lighting Feedback for Overload Warning

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Solution Overview

Problem

Power tools, especially those for cutting, grinding, or drilling, face overloading issues when encountering high resistance, leading to potential damage to electric motors and battery cells, with existing solutions like temperature-dependent shutdowns being inconvenient and potentially lengthy, disrupting user work and affecting quality.

Innovation Solution

A control system that couples a power tool with a separate lighting device, using sensor data to generate light pulses or varying light intensity to warn the user of impending overload, allowing for proactive avoidance of critical conditions without interrupting the tool's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature-dependent shutdown is implemented to protect the electrical consumer, then the power tool is protected from overload damage, but the user experience deteriorates due to work interruptions and quality loss

Engineering Contradiction:

Improveprotection from overloadVSAvoiduser comfort

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The lighting device provides advance warning to the user before the electrical consumer reaches critical temperature or overload conditions. By illuminating the workspace in advance of the dangerous state, the user can adjust their actions to prevent the shutdown condition from occurring, thus maintaining both protection and operational continuity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by monitoring operating parameters (temperature, current) and providing visual feedback through the lighting device. The lighting state changes in response to sensor data, creating a closed-loop system that informs the user of the tool's state and guides them toward safe operating practices

Inventive Principle:

Principle #23Feedback

2Reliability

If conservative permissible limit values are used for current to prevent damage, then the electrical consumer is protected from overload, but the productivity decreases due to frequent shutdowns

Engineering Contradiction:

Improveprotection of electrical consumerVSAvoidwork continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system takes preliminary action by warning the user before the conservative limit is reached. The lighting device provides advance notice when approaching the permissible current limit, allowing the user to reduce load or pause before the shutdown threshold is hit, thus maintaining productivity while still protecting the electrical consumer

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The lighting device acts as an intermediary between the sensor monitoring system and the user. Instead of direct shutdown at the conservative limit, the lighting provides a intermediate warning state that mediates between continuous operation and protective shutdown, enabling smoother transitions and reduced productivity loss

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If temperature monitoring with shutdown is implemented, then the electrical consumer is protected from damage, but the cooling time increases operational interruptions

Engineering Contradiction:

Improveprotection from thermal damageVSAvoidcooling downtime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The lighting device provides preliminary warning before thermal damage conditions are reached. By illuminating the workspace in advance of critical temperature thresholds, the user can take preventive actions (reducing feed rate, pausing operation) that avoid the need for extended cooling periods, thus reducing time loss while maintaining thermal protection

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system allows the user to skip the lengthy cooling downtime by providing advance warning that enables proactive load reduction. The lighting feedback creates an opportunity to rush through the critical phase by adjusting operations before the thermal threshold is reached, rather than waiting for passive cooling

Inventive Principle:

Principle #21Skipping (Rushing through)

Data Source

PatentEP4275843A1Control of a power tool and a separate lighting device

Publication Date: 2023.11.15 EINHELL GERMANY AG

Figure 1

AI summary

A control system (2) for a power tool (3) and a separately arranged lighting device (4) comprises a first control circuit (7) and a sensor (13) for the power tool (3) and a second control circuit (8) for the lighting device (4). The sensor (13) is configured to generate a sensor signal depending on the value of an operating parameter of the power tool (3). The first control circuit (7) is configured to transmit information regarding the value of the operating parameter to the second control circuit (8) depending on the sensor signal.The second control circuit (8) is configured to control a light source (15) of the lighting device (4) depending on the transmitted information to emit one or more light pulses, wherein a pulse parameter relating to a pulse duration of the light pulses and/or a pulse amplitude of the light pulses and/or a frequency of the light pulses and/or a duty cycle of the light pulses depends on the value of the operating parameter and/or to emit light whose light intensity depends on the value of the operating parameter.