Reciprocating Tool Motor Cutoff Circuit for Precise Stop Timing

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Solution Overview

Problem

Existing reciprocating tools experience delays in stopping the electric motor due to processing loads on the microprocessor, leading to inefficiencies in operation.

Innovation Solution

Incorporating a signal cutoff circuit with wired logic that immediately cuts off the drive signal to the electric motor when the reciprocating member reaches a specified position, eliminating delays caused by microprocessor processing loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a microprocessor is used to control the stopping of the electric motor, then the control system can be programmable and adaptable, but the stopping operation is delayed due to processing load

Engineering Contradiction:

Improveprogrammable controlVSAvoidstopping delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The control system is segmented into two independent parts: a microprocessor for high-level control decisions and a dedicated stop circuit for immediate motor stopping. The stop circuit monitors the reciprocating member's position directly and cuts off the drive signal without waiting for microprocessor processing, thereby eliminating stopping delay while preserving programmable control capabilities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A dedicated stop circuit acts as an intermediary between the position detection and motor drive. This intermediary circuit receives position information and directly interrupts the drive signal to the motor when the reciprocating member reaches the specified position, bypassing the microprocessor's processing queue and ensuring immediate response.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If microprocessor processing is used for position-based control, then flexible control logic can be implemented, but operational precision is reduced due to processing delays

Engineering Contradiction:

Improvecontrol logic flexibilityVSAvoidpositioning precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The control system is divided into flexible microprocessor-based control for decision-making and a dedicated precision stopping circuit for accurate position-based motor cutoff. This segmentation allows the stopping operation to be precisely timed based on reciprocating member position without being affected by microprocessor processing variations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stop circuit serves as a precision intermediary that translates position detection into immediate motor stopping action. It ensures that the motor stops at the exact specified position by directly cutting off the drive signal when the reciprocating member reaches the target position, independent of microprocessor processing speed.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Extent of automation

If continuous monitoring and processing by microprocessor is performed, then comprehensive control can be achieved, but system response time increases

Engineering Contradiction:

Improvecomprehensive controlVSAvoidresponse speed

Core Design Contradiction:

Extent of automationVSSpeed

Solution Approach 1:

The automated control system is segmented into comprehensive microprocessor control for overall system management and a dedicated fast-response stop circuit for immediate motor cutoff. The stop circuit provides direct monitoring of reciprocating member position and instantly cuts off the drive signal when the specified position is reached, achieving rapid response independent of microprocessor processing speed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stop circuit acts as a fast-response intermediary between position monitoring and motor control. It directly intercepts and cuts off the drive signal when the reciprocating member reaches the specified position, providing immediate response that complements the comprehensive but slower microprocessor control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250360606A1Reciprocating tool, and method for controlling electric motor of reciprocating tool

Publication Date: 2025.11.27 MAKITA CORP

AI summary

One aspect of the present disclosure provides a reciprocating tool including a reciprocating member, an electric motor, a transmission device, a control circuit, a drive circuit, a position detector, and a signal cutoff circuit. The drive circuit (i) receives at least one drive signal, and (ii) drives the electric motor in accordance with the at least one drive signal received. The position detector outputs a position detection signal each time the reciprocating member reaches a specified position in at least one reciprocating motion thereof. The signal cutoff circuit includes wired logic configured to cut off the drive circuit from the at least one drive signal in response to the position detector outputting or having output the position detection signal.