Impact Tool Control Mode for Higher Transition Torque

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Solution Overview

Problem

Existing impact tools transition from rotary mode to impact mode at a torque level that may cause inadvertent damage to fasteners or workpieces, necessitating a higher transition torque for certain operations.

Innovation Solution

An impact tool with a controller that allows transition from rotary to impact mode at a customizable control transition torque greater than the normal transition torque, using power limits and time intervals to manage torque and inertia.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the impact mechanism transitions from rotary mode to impact mode at the normal transition torque, then the impact tool can deliver high torque through impacting, but this may cause inadvertent damage to fasteners or workpieces

Engineering Contradiction:

Improvetransition torqueVSAvoiddamage to fastener or workpiece

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The controller dynamically adjusts the power delivery to the motor based on operational conditions, enabling transition between normal mode and control mode. In control mode, the controller limits power delivery to prevent the impact mechanism from transitioning to impacting mode at the normal transition torque, thereby avoiding damage while still allowing high torque delivery when needed

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters by introducing a control mode that modifies the power delivery characteristics. The controller adjusts motor power limits and monitoring thresholds to raise the effective transition torque above the normal transition torque, preventing inadvertent impacting during sensitive operations

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the controller limits power delivery to prevent transition to impact mode, then damage to fasteners is avoided, but the impact tool cannot deliver maximum torque when needed

Engineering Contradiction:

Improvedamage preventionVSAvoidtorque delivery

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The controller dynamically switches between normal mode and control mode based on operational requirements. In control mode, power is limited to prevent impacting; when the operation is complete or conditions change, the controller can transition back to normal mode to restore full power delivery capability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The controller periodically monitors operational parameters such as motor current, speed, and load conditions to determine when to transition between modes. This periodic monitoring and mode switching allows the system to alternate between protective limiting and full-power operation based on real-time conditions

Inventive Principle:

Principle #19Periodic action

3Reliability

If the impact mechanism uses mechanical characteristics to determine transition torque, then the transition point is fixed and reliable, but it cannot be adjusted for different operational requirements

Engineering Contradiction:

Improvetransition point consistencyVSAvoidtransition torque adjustability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the purely mechanical transition determination with an electronic control system. The controller monitors motor parameters and can prevent mechanical transition to impacting mode even when torque reaches the normal transition level, substituting electronic decision-making for mechanical inevitability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the transition behavior by introducing controllable parameters through the controller. By adjusting power delivery limits and monitoring thresholds, the effective transition torque becomes variable rather than fixed, allowing adaptation to different fastener types and workpiece conditions

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250353151A1Impact tool with control mode

Publication Date: 2025.11.20 BLACK & DECKER CORP

AI summary

An impact tool includes a controller configured to control power being delivered to the and operable in one of: (a) a normal mode where the controller allows power to be delivered to the motor so that the impact mechanism transitions from operation in the rotary mode to operation in the impacting mode when an output torque exceeds a normal transition torque; and (b) a control mode where the controller controls power being delivered to the motor so that the impact mechanism transitions from operation in the rotary mode to operation in the impacting mode when an output torque exceeds a control transition torque that is greater than the normal transition torque.