Interlocking Adapter Periodic Switching to Reduce Power and Heat

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Solution Overview

Problem

Existing interlocking adapters for electric apparatuses and working machines require large sizes due to the need for continuous load current supply, leading to increased power consumption and heat generation, which results in inefficiencies and potential downsizing limitations.

Innovation Solution

The interlocking adapter incorporates a current path with a switch and controller that turns the switch on and off synchronously with the alternating-current voltage, reducing the effective load current supplied to the electric load, thereby minimizing power consumption and heat generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous load current is supplied to the electric load to enable the electric apparatus to detect operation of the working machine, then the interlocking function is achieved, but the adapter size increases and power consumption increases

Engineering Contradiction:
Improveinterlocking detection functionVSAvoidadapter size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies periodic action by turning the switch on and off in synchronization with the alternating-current voltage cycles. Instead of continuous current supply, the load current is supplied periodically at specified ratios (e.g., 1/4, 1/2, or 3/4 of the half-cycle period), which reduces the total energy consumption and heat generation while still providing sufficient detection signals for the electric apparatus to recognize working machine operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the parameter of current supply from continuous to pulsed/intermittent by controlling the switch timing. The controller adjusts the duty cycle (ratio of on-time to half-cycle period) to optimize between detection reliability and power consumption reduction, thereby reducing adapter size without compromising the interlocking function.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If continuous load current is supplied to the electric load, then the interlocking function is achieved, but power consumption increases

Engineering Contradiction:
Improveinterlocking detection functionVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by turning the switch on and off in synchronization with the alternating-current voltage cycles. Instead of continuous current supply, the load current is supplied periodically at specified ratios (e.g., 1/4, 1/2, or 3/4 of the half-cycle period), which reduces the total energy consumption and heat generation while still providing sufficient detection signals for the electric apparatus to recognize working machine operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies partial action by supplying load current only for a portion of each half-cycle period rather than continuously. The switch is turned on at a specified ratio of the half-cycle period, providing just enough current to enable detection by the electric apparatus while minimizing unnecessary energy consumption during the off periods.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If continuous load current is supplied to the electric load, then the interlocking function is achieved, but heat generation increases requiring heat dissipation measures

Engineering Contradiction:
Improveinterlocking detection functionVSAvoidheat generation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies periodic action by turning the switch on and off in synchronization with the alternating-current voltage cycles. Instead of continuous current supply, the load current is supplied periodically at specified ratios (e.g., 1/4, 1/2, or 3/4 of the half-cycle period), which reduces the total energy consumption and heat generation while still providing sufficient detection signals for the electric apparatus to recognize working machine operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent converts the potentially harmful continuous heat generation into beneficial periodic pulses. By timing the current supply to coincide with specific phases of the AC voltage cycle and using appropriate duty ratios, the system generates just enough heat for detection purposes while avoiding excessive heat accumulation that would require dissipation measures.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

This approach reduces the amount of load current and heat generation, allowing for a downsized interlocking adapter while maintaining effective operation in interlocking mode with working machines.

Implementation Method 1

heat is generated due to flow of the electric current through the electric load

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3505034B1Interlocking adapter, and method for operating electric apparatus in interlocking manner with working machine
Publication Date: 2025.02.12 MAKITA CORP
  • EP3505034B1 patent drawingFigure 1
  • EP3505034B1 patent drawingFigure 2
  • EP3505034B1 patent drawingFigure 3

AI summary

An interlocking adapter (50) in one aspect of the present disclosure includes a current path, an electric load (62), a switch (64), and a controller (70). The controller (70) turns on and off the switch (64) in synchronization with a change of an alternating-current voltage received from an electric outlet (32) of an electric apparatus (20) in response to reception of an interlocking command signal from a working machine (10) so as to supply a load current from the electric outlet (32) to the electric load (62). The controller (70) turns on and off the switch (64) at a specified ratio of a time every 1/2 cycle of the alternating-current voltage.