Counterweight Driver Mechanism for Perpendicular Nail Striking

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Solution Overview

Problem

Conventional nail drivers experience difficulty in striking nails perpendicularly to a workpiece surface due to reaction forces, leading to user burden and potential damage to the workpiece, as the ejection hole is moved away from the workpiece during the striking operation.

Innovation Solution

A driver design that uses a resilient member, such as a coil spring, to compress and release energy, allowing the plunger to strike the nail while a counter-impact weight moves in the opposite direction, canceling out reaction forces and maintaining the ejection hole's orientation, thus reducing user effort and preventing workpiece damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the plunger is accelerated in the impacting direction to strike the nail, then the striking force is generated, but a reaction force is generated that moves the ejection hole away from the workpiece, making it difficult to maintain perpendicular striking orientation

Engineering Contradiction:
Improvestriking forceVSAvoidmaintaining perpendicular striking orientation
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent introduces a weight (counterweight) that moves in the opposite direction to the plunger during the striking operation. When the plunger accelerates downward to strike the nail, the counterweight accelerates upward, generating a counter-reaction force that cancels out the reaction force acting on the housing. This allows the ejection hole to maintain its orientation perpendicular to the workpiece surface without being displaced by the reaction force.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Stability of the object's composition

If the user presses the ejection hole against the workpiece excessively to restrict the reaction force, then the housing stability is improved, but the workpiece surface may be damaged

Engineering Contradiction:
Improvehousing stabilityVSAvoidworkpiece surface damage
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

By introducing the counterweight mechanism, the patent eliminates the need for excessive user pressure on the ejection hole. The counterweight automatically generates a counter-reaction force that balances the reaction force from plunger acceleration, thereby stabilizing the housing without requiring the user to press the ejection hole excessively against the workpiece surface, thus preventing surface damage.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Stability of the object's composition

If a counterweight is introduced to cancel reaction forces, then the housing stability is improved, but the device complexity increases

Engineering Contradiction:
Improvehousing stabilityVSAvoiddevice structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent combines the counterweight with the existing spring mechanism. The spring is positioned between the plunger and the counterweight, serving dual purposes: storing elastic energy to drive the plunger and providing the counterbalancing force for the counterweight. This integration reduces the number of separate components and simplifies the overall device structure while maintaining the reaction force cancellation function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring in the patent performs multiple functions: it stores elastic energy for plunger acceleration, provides the driving force for the counterweight movement, and acts as a mechanical element connecting the plunger and counterweight. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration enhances workability by allowing precise perpendicular striking without lifting the driver housing from the workpiece, reducing pressure marks, and simplifies manufacturing while maintaining the driver's compactness.

Implementation Method 1

a spring configured to urge the plunger 7 in an impact direction, and a motor used for accumulating an resilient energy in the spring

Methodology Applied
Scientific EffectElastic potential energy: Elasticity

Implementation Method 2

when the compression is released, the resilient energy accumulated in the resilient member causes the plunger 7 to move in the impact direction

Methodology Applied
Scientific EffectResilient energy release: Elastic Recovery

Data Source

PatentEP3195986B1Drive-in machine
Publication Date: 2022.06.08 KOKI HLDG CO LTD
  • EP3195986B1 patent drawingFigure 1
  • EP3195986B1 patent drawingFigure 2
  • EP3195986B1 patent drawingFigure 3~4

AI summary

In order to provide a driver for reducing reaction generated to a driver main body, the driver 1 includes a nose portion 3 provided in a housing 2 and extending in a longitudinal direction, the nose portion being configured to allow a fastener to pass therethrough, a plunger 7 configured to move in an impact direction parallel to the longitudinal direction to impact the fastener through the nose portion, a weight 8, and a coil spring 9 configured to be compressed by a motor 5 in the longitudinal direction. a release of the compression causing the plunger 7 to move in the impact direction, while causing the weight 8 to move in a counter-impact direction which is away from the plunger 7. The coil spring 9 is provided between the plunger 7 and the weight 8. The coil spring has one end portion urging the plunger 7, and another end portion urging the weight 8.