Laser-Guided Rotary Hand Tool for Consistent Screw Head Depth
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Solution Overview
Problem
Existing motor-driven hand tools lack the ability to automatically switch off at a definable distance from a workpiece, particularly when dealing with uneven or angled surfaces, which can lead to inconsistent drilling or screwing depths and potential damage.
Innovation Solution
Incorporating a light sensor and electronic control unit that interacts with a leveling laser to switch off the rotary drive when the light sensor detects the laser beam, ensuring the tool stops in a fixed plane, and optionally considering physical properties like color, intensity, and coherence to prevent unintended switching off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual depth adjustment mechanism is used, then device complexity is reduced, but manufacturing precision deteriorates due to inconsistent drilling depths on uneven surfaces
Solution Approach 1:
The patent replaces manual mechanical depth adjustment with an optical sensing system (light sensor detecting laser beam) and electronic control system. The light sensor detects when the drill bit reaches the reference plane, and the control unit automatically deactivates the motor, eliminating the need for manual depth measurement and adjustment mechanisms.
Solution Approach 2:
The patent introduces a laser beam as an intermediary reference plane that the light sensor detects. This laser reference plane serves as the mediator between the uneven workpiece surface and the drilling depth control, allowing consistent depth measurement regardless of surface variations.
2Manufacturing precision
If automatic light detection system is added, then manufacturing precision is improved, but device complexity increases due to additional sensors and control units
Solution Approach 1:
The control unit serves multiple functions: it receives signals from the light sensor, determines when the reference plane is reached, and deactivates the motor. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing complexity while achieving precise depth control.
3Ease of operation
If light sensor detects any light source, then ease of operation is improved, but reliability deteriorates due to unintended switching off from non-laser light sources
Solution Approach 1:
The light sensor is designed with specific sensitivity characteristics tailored to detect the wavelength and properties of laser light. This localized optimization of the sensor's detection properties ensures it responds to the intended laser reference plane while being less sensitive to other ambient light sources, thereby preventing false activation.
4Productivity
If drilling depth is manually controlled, then device complexity is reduced, but productivity deteriorates due to time-consuming depth adjustment and measurement
Solution Approach 1:
The system performs self-service by automatically detecting when the drill bit reaches the reference plane through the light sensor and laser beam interaction. The control unit autonomously deactivates the motor without requiring operator intervention for depth measurement or adjustment, thereby increasing productivity while managing complexity through automation.
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 solution allows for precise control of drilling or screwing operations, ensuring that holes or screw heads are in a single plane even on uneven surfaces, enhancing accuracy and safety by preventing accidental tool activation from unintended light sources.
Implementation Method 1
The light sensor detects light incident laterally to a rotational axis of the hand tool, in particular a laterally incident laser beam
Data Source
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AI summary
The invention proposes equipping a motor-driven rotary hand tool (2), such as a cordless screwdriver (1), with photodiodes (6) and an electronic control unit (5) that switches off an electric motor (3) of the cordless screwdriver (1) when a laser beam (12) of a leveling laser (11) strikes one of the photodiodes (6). This allows screws (17) to be driven into a workpiece (16) such that their screw heads (20) are in the same plane.