Bit Holder with Automatic Coupling Sleeve Transition

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Solution Overview

Problem

Existing bit holders fail to efficiently manage the coupling and uncoupling process, particularly when screwing into plasterboard walls, as they often require manual intervention and lack a seamless transition from coupling to freewheeling positions, leading to incomplete screwing operations.

Innovation Solution

A bit holder design featuring a coupling sleeve that surrounds the drive shaft, allowing axial displacement from a coupling position to a freewheeling position, utilizing interlocking polygonal surfaces for torque transmission and a spring mechanism to automatically switch between these states, ensuring secure screwing and easy bit removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a manual coupling and uncoupling mechanism is used, then the bit holder requires manual intervention to switch between coupling and freewheeling positions, but this increases the complexity of operation and reduces productivity

Engineering Contradiction:
Improveoperation simplicityVSAvoidscrewing speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The bit holder automatically switches between coupling and freewheeling positions based on the screwing process stage. The actuating sleeve is displaced axially by the screw head during screwing, automatically triggering the uncoupling of the coupling elements from the drive shaft, eliminating the need for manual intervention and enabling continuous high-speed operation

Inventive Principle:
Principle #25Self-service

2Reliability

If the coupling elements remain engaged throughout the screwing process, then continuous torque transmission is maintained, but the screw cannot be fully driven into plasterboard walls where the head enters the surface

Engineering Contradiction:
Improvetorque transmission stabilityVSAvoidadaptability to different screwing stages
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The coupling elements dynamically transition between engaged and disengaged states based on the axial position of the actuating sleeve. During the initial screwing phase, the coupling elements are engaged to transmit torque. When the screw head enters the plasterboard surface, the actuating sleeve displaces axially, causing the coupling elements to deflect radially and disengage, allowing the screw to be fully driven in without requiring manual uncoupling

Inventive Principle:
Principle #15Dynamics

3Extent of automation

If a spring mechanism is used to maintain coupling position, then automatic transition between coupling and freewheeling positions is achieved, but the device complexity increases

Engineering Contradiction:
Improveautomatic coupling transitionVSAvoidmechanism complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The actuating sleeve serves as an intermediary component that translates the axial movement of the screw head into radial displacement of the coupling elements. The spring mechanism provides the necessary restoring force to maintain the coupling elements in the engaged position during normal screwing, while allowing automatic disengagement when the screw head enters the surface, achieving automation with minimal additional complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design enables smooth and automatic transition between coupling and freewheeling positions, facilitating complete screwing into plasterboard walls without manual intervention, ensuring secure screwing and easy bit extraction.

Implementation Method 1

a spring mechanism to automatically switch between these states

Methodology Applied
Scientific EffectSpring mechanism: Spring

Data Source

PatentEP3141346B1Bit holder with depth limit
Publication Date: 2019.09.25 WOLFCRAFT GMBH
  • EP3141346B1 patent drawingFigure 1
  • EP3141346B1 patent drawingFigure 2~4
  • EP3141346B1 patent drawingFigure 5~6

AI summary

The invention relates to a bit holder with a drive shaft (1) rotatable about a rotary axis, with an output sleeve part (20) having an insertion opening (21) for inserting a screwdriver bit (33), with a coupling sleeve (26) that at least partially surrounds the drive shaft (1) and which is displaceable in the direction of the axis of rotation from a coupling position, in which a coupling zone associated with the coupling sleeve (26), e.g. a coupling contact surface (25'), bears against a counter-coupling zone, e.g. a coupling surface (2') of the drive shaft (1), so that a rotation of the drive shaft (1) is transmitted to the output sleeve part (20), to a free-running position, in which the coupling zone and the counter-coupling zone are each located in free-running sections (3, 39) of the drive shaft (1) and output sleeve part (20), respectively, so that a rotation of the drive shaft (1) is not transmitted to the drive shaft (1). the output sleeve part (20) is transferred.The coupling sleeve (26) is axially fixed to an actuating sleeve (10), which forms a stop at its end pointing towards the insertion opening (21).