Screwdriver Depth Control via Sensor and Spring

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional screwdriving tools require mechanical clutches for depth control, which are bulky, prone to wear, and require significant axial force, limiting their versatility and compactness.

Innovation Solution

A screwdriving tool with a removable contact trip assembly, sensor, and on-board controller that eliminates the need for a mechanical clutch by using a biasing spring to electronically control the screwdriving depth, allowing for accurate and repeatable depth control without the need for manual axial force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical clutch is used for depth control, then depth control function is provided, but the device becomes bulky and complex

Engineering Contradiction:
Improvedepth controlVSAvoidmechanical clutch
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical clutch system with an electronic sensor-based depth control system. A sensor detects when the fastener has been driven to the desired depth and sends a signal to the motor controller to stop operation, eliminating the need for mechanical clutch components and reducing overall device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a sensor as an intermediary element between the motor and the fastener driving process. The sensor monitors the driving depth and communicates this information to the control system, serving as a mediator that enables precise depth control without requiring direct mechanical intervention.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a mechanical clutch is used for depth control, then depth control function is provided, but the device requires significant axial force

Engineering Contradiction:
Improvedepth controlVSAvoidaxial force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The electronic sensor system replaces the mechanical force-based depth control mechanism. Instead of relying on axial force to engage or disengage clutch components, the sensor detects depth through non-contact or minimal-contact means, significantly reducing the axial force requirement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a mechanical clutch is used for depth control, then depth control function is provided, but wear and mechanical breakdown occur

Engineering Contradiction:
Improvedepth controlVSAvoidclutch lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces the wear-prone mechanical clutch with an electronic sensor and motor control system. The sensor has no moving parts that contact each other during operation, and the motor control is achieved through electronic signals rather than mechanical engagement, eliminating wear and extending system lifespan.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The sensor system is self-monitoring and automatically communicates depth information to the control system without requiring mechanical adjustment or maintenance. The system serves itself by continuously monitoring its own operational parameters and making real-time control adjustments.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If a removable contact trip assembly is used, then versatility is improved, but device complexity increases

Engineering Contradiction:
Improvetool configurationVSAvoidremovable assembly
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the depth control system into a removable contact trip assembly that can be detached and attached as needed. This segmentation allows the basic driver tool to remain simple while offering enhanced functionality through the optional attachment, managing complexity through modularity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The removable contact trip assembly serves multiple functions: it provides depth control capability, can be removed to restore the tool to its basic configuration, and potentially offers different sensing options. This multi-functionality justifies the added complexity by providing versatile operational capabilities.

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

The solution provides a more compact and versatile screwdriving tool that can accurately control depth without mechanical clutch wear, enhancing usability and reducing operator effort.

Implementation Method 1

One of the sensor and the sensor target is coupled to the output member and the nose element for axial movement relative to the one of the sensor and the sensor target

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The sensor provides a sensor signal that is based upon a distance between the sensor and the sensor target

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP2444202B1Removable contact trip assembly
Publication Date: 2019.07.31 BLACK & DECKER CORP
  • EP2444202B1 patent drawingFigure 1~2
  • EP2444202B1 patent drawingFigure 2A
  • EP2444202B1 patent drawingFigure 2B~2C

AI summary

A screwdriving tool (10) that includes a driving tool (driver) (12), a sensor (42), a sensor target and a contact trip assembly (14) that is coupled to the driving tool and has a nose element (72). The driver (12) has a housing (20), a motor (22) and an output member (28) that is driven by the motor. One of the nose element (72) and the output member (28) is axially movable and biased by a spring (76) into an extended position. The sensor (42) and sensor target are configured to cooperate to permit the sensor to provide a sensor signal that is indicative of movement of the one of the nose element (72) and the output member (28). The motor is controllable in a first operational mode and at least one rotational direction based in part on the sensor signal.