Shearing Tool Anti-Binding Motor Reversal

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Solution Overview

Problem

Existing shearing tools often jam when cutting large workpieces or foreign objects, and current control systems fail to distinguish between workpieces and foreign objects, making it difficult to unjam the blades effectively.

Innovation Solution

A shearing tool with a controller that operates a drive unit in an anti-binding mode by alternately reversing the direction of the motor's input at least twice, allowing for effective unjamming of blades by reversing the direction of the shearing motion, which helps to separate the workpiece or foreign object from the blades.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the shearing blades are used to cut large workpieces or multiple workpieces simultaneously, then the productivity is improved, but the blades may jam

Engineering Contradiction:

Improvecutting capacityVSAvoidblade jamming

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The control system changes the operational parameters of the motor by reversing its direction of rotation. When jamming is detected or triggered, the controller reverses the motor's rotational direction, which reverses the shearing motion of the blades. This parameter change allows the blades to back out of the jammed workpiece, resolving the contradiction between cutting capacity and reliability.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the trigger switch is released and re-activated to unjam the blades, then the motor stops and restarts, but the blades have no additional momentum to unjam

Engineering Contradiction:

Improveunjamming capabilityVSAvoidunjamming effectiveness

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Instead of simply stopping and restarting the motor in the same direction, the control system inverts the motor's rotational direction by activating it in reverse. This inversion provides the blades with momentum in the opposite direction, enabling them to back out of the jammed workpiece effectively, thus resolving the contradiction between ease of operation and unjamming effectiveness.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If the control means attempts to cut through a foreign object, then the blades may be damaged, but the control means cannot distinguish between workpiece and foreign object

Engineering Contradiction:

Improvecutting capabilityVSAvoidblade damage from foreign objects

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The control system takes preliminary anti-action by implementing a reversal mechanism that prevents blade damage from foreign objects. When a foreign object is detected or suspected, the system reverses the motor direction, causing the blades to back out before significant damage can occur. This preliminary protective action resolves the contradiction between cutting versatility and blade protection.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS9980438B2Shearing tool

Publication Date: 2018.05.29 BLACK & DECKER CORP

AI summary

A method for operating a shearing tool that includes: operating a first switch to control a drive unit to drive a blade of a blade set; and operating a second switch to cause the drive unit to operate in an anti-binding mode in which a direction of an input to the drive unit is alternated at least twice. A shearing tool is also provided.