Co-rotation Preventing Mechanism for Screw Driver Bit Alignment

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional screw drivers face issues with unintentional rotation of the end bit during the OFF state of the clutch mechanism, making it difficult to align with the screw head, especially when the user forgets to switch to reverse rotation, leading to misalignment and potential damage.

Innovation Solution

A screw driver design incorporating a housing, drive portion, end bit mounting portion, clutch mechanism, and a co-rotation preventing mechanism that engages with the end bit mounting portion to prevent forward rotation while allowing reverse rotation, ensuring precise alignment and control during screw operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the clutch mechanism is turned OFF to stop power transmission, then energy consumption is reduced, but the end bit may unintentionally rotate due to residual friction or user error in switch position

Engineering Contradiction:
Improveenergy consumptionVSAvoidalignment accuracy
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The co-rotation preventing mechanism is designed to preemptively counteract the harmful effect of unintentional end bit rotation. When the clutch mechanism is OFF, the preventing mechanism engages to block forward rotation of the end bit mounting portion, thereby preventing misalignment before it can occur. This preliminary anti-action ensures that even if residual friction or user error causes the clutch to slip, the end bit remains securely aligned with the screw head.

Inventive Principle:
Principle #9Preliminary anti-action

2Ease of operation

If the clutch mechanism is turned OFF to prevent power transmission, then unwanted driving force is eliminated, but alignment becomes difficult due to residual friction or switch position errors

Engineering Contradiction:
Improvealignment easeVSAvoidalignment reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The co-rotation preventing mechanism performs a preliminary action by engaging the prevention engagement portion before any unintentional rotation can occur. The preventing mechanism is pre-configured to block the rotational path of the end bit mounting portion when the clutch is OFF, ensuring that the end bit remains in precise alignment with the screw head groove from the moment power transmission is stopped.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If a simple clutch mechanism is used to control power transmission, then device complexity is reduced, but unintentional rotation occurs due to residual friction or user error

Engineering Contradiction:
Improvemechanism complexityVSAvoidrotation control reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The rotation control system is segmented into two independent functional modules: the clutch mechanism for controlling power transmission, and the co-rotation preventing mechanism for blocking unintentional rotation. The preventing mechanism includes separate components (prevention engagement portion, prevention engaging protrusion, and preventing member) that work independently from the clutch mechanism, allowing each module to perform its specific function with high reliability without increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

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 co-rotation preventing mechanism effectively prevents unintentional rotation of the end bit during the clutch OFF state, enhancing user control and reducing misalignment issues, thereby improving the accuracy and safety of screw driving operations.

Implementation Method 1

the spring section (63) is configured to prevent the end bit mounting portion (5) from being rotated in a forward direction by coil binding when the end bit mounting portion is rotated in the forward direction and to allow the end bit mounting portion to rotate in a reverse direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2127811B1Screw driver
Publication Date: 2012.08.15 KOKI HLDG CO LTD
  • EP2127811B1 patent drawingFigure 1
  • EP2127811B1 patent drawingFigure 2~4
  • EP2127811B1 patent drawingFigure 5~7

AI summary

A screw driver (1) capable of avoiding co-rotation of an end bit and a motor (3) in case of sharp shooting the end bit with a groove in a head of a screw. A co-rotation preventing mechanism is engageable with an end bit mounting portion (5) when the end bit mounting portion (5) is at a frontward position to prevent the end bit mounting portion (5) from being rotated in the forward direction and to allow the end bit mounting portion (5) to rotate in the reverse direction. The preventing mechanism is disengageable from the end bit mounting portion when the end bit mounting portion is at the rearward position to allow the end bit mounting portion to rotate in both forward and reverse directions.