Retractable Bit Holder with Segmented Radial Clips

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Solution Overview

Problem

Existing power tools with integral bit holders are unable to store bits with a range of diameters, as they are designed to accommodate only bits of the same diameter.

Innovation Solution

A retractable bit holder with a tube configured for longitudinal slidable movement and a bit-mounting member with multiple clip members, allowing for the storage of bits with different diameters by accommodating various radial distances on the bit-mounting member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional integral bit holder design is used, then bits of a single diameter can be stored, but bits with different diameters cannot be accommodated

Engineering Contradiction:
Improveability to store bits with different diametersVSAvoidcomplexity of bit holder structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bit holder is divided into multiple radial sections, each with a different radial distance from the tube. Each section can accommodate bits of specific diameters, allowing the single bit holder to store bits with varying diameters through its segmented radial structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the bit holder have different local properties - specifically, different radial distances from the tube. This local variation in geometry allows each section to accommodate bits of different diameters appropriately, with larger radial distances for larger bits and smaller radial distances for smaller bits

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If bits of various diameters are stored in the bit holder, then versatility is improved, but the risk of bits falling out increases

Engineering Contradiction:
Improveability to accommodate different bit diametersVSAvoidsecurity of bit retention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Each radial section of the bit holder is designed with specific clip members positioned at appropriate radial distances to securely retain bits of corresponding diameters. The clip members are configured to engage with the bits and prevent them from falling out, with each section's retention mechanism tailored to its specific bit size

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The clip members are designed to automatically engage with and secure the bits when they are placed in the bit holder. The springs provide continuous retention force, and the clips self-adjust to accommodate different bit diameters while maintaining secure retention without requiring additional active control mechanisms

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4259385B1Impact driver with retractable bit-holder
Publication Date: 2025.05.07 FRUHM HERMANN
  • EP4259385B1 patent drawingFigure 1
  • EP4259385B1 patent drawingFigure 2
  • EP4259385B1 patent drawingFigure 3

AI summary

A retractable bit holder (10) for a bit-using power tool (12) provides storage for bits within the power tool. The bit holder (10) has a tube (18) that slides along a cylindrical member (28) of the casing (14) of the power tool between open and closed positions. A bit-mounting member (20) extends radially outwardly from the tube and has a plurality of clip members (32) projecting from it, the clip members being configured for removably holding bits (16). The bit-mounting member (20) has a first portion (34) arranged for holding bits at a greater distance from the tube than a second portion (38) of the bit-mounting member, thereby providing storage of bits having a range of diameters. The bit holder is sized to provide a recess (46) between the bit-mounting member and an internal wall (26) within the casing of the power tool. The bit holder may optionally be contained in a bit cartridge that is detachable from the power tool.