Bit Holder Assembly Shuttle Retention via Extracted C-Ring

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Solution Overview

Problem

Conventional bit holder assemblies require additional machining and expense to prevent the shank and shuttle from falling out, as the shuttle is typically larger than the shank receiving end, necessitating a large protrusion on the shank for retention.

Innovation Solution

The bit holder assembly is designed with a barrel that allows the shuttle to be inserted through the bit receiving end, using a compressible retaining member like a c-ring or retaining balls to retain the shuttle within the barrel, eliminating the need for a large protrusion on the shank and simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large protrusion is added to the shank to retain the shuttle, then the shuttle can be securely retained in the barrel, but the manufacturing complexity and cost increase due to additional machining

Engineering Contradiction:

Improveshuttle retentionVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The retention function is extracted from the shank and transferred to a separate retaining member (such as a retaining ring or clip). This allows the shuttle to be securely retained without requiring additional machining of the shank itself, thereby resolving the contradiction between reliable retention and ease of manufacture

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The bit holder assembly is segmented into distinct functional components: the shank, the shuttle, and a separate retaining member. This segmentation allows each component to be manufactured independently with simpler processes, while the retaining member provides the necessary retention function without complicating the shank manufacturing

Inventive Principle:

Principle #1Segmentation

2Reliability

If the shuttle is made larger to improve tool bit retention, then the tool bit can be securely held, but the shuttle cannot be inserted through the bit receiving end due to size constraints

Engineering Contradiction:

Improvetool bit retentionVSAvoidassembly ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

Instead of inserting the shuttle through the bit receiving end (which requires the shuttle to be small), the design inverts the insertion approach: the shuttle is inserted through the shank receiving end along with the shank. This allows the shuttle to be larger for better tool bit retention while simplifying the assembly process by using a single insertion path

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If additional machining is performed on the shank to create retention features, then the shuttle can be retained, but the manufacturing cost and time increase

Engineering Contradiction:

Improveshuttle retentionVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The retaining member is designed to be pre-formed and ready for installation, eliminating the need for time-consuming machining operations on the shank during assembly. The retaining member can be quickly installed using simple operations such as snap-fitting or clipping, thereby reducing assembly time while maintaining reliable shuttle retention

Inventive Principle:

Principle #10Preliminary action

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 design reduces manufacturing complexity and cost by allowing the shank to be retained without additional machining, enabling efficient assembly and secure retention of the shuttle and tool bit within the barrel.

Implementation Method 1

The shuttle is biased toward the bit receiving end by the biasing member

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

The retaining member engages the shuttle and limits movement of the shuttle relative to the barrel

Methodology Applied

Scientific EffectMechanical Constraint: Mechanical Force

Data Source

PatentUS10343266B2Bit holder assembly

Publication Date: 2019.07.09 MILWAUKEE ELECTRIC TOOL CORP

AI summary

A bit holder assembly includes a barrel having a shank receiving end, a bit receiving end, and an inner wall extending between the shank receiving end and the bit receiving end. The bit holder assembly also includes a shank sized and shaped to be received within the barrel. The shank is insertable into the barrel from the shank receiving end. The bit holder assembly further includes a shuttle having an annular recess. The shuttle is sized and shaped to be received within the barrel and is insertable into the barrel from the bit receiving end. The bit holder assembly also includes a retaining member sized and shaped to be received within the annular recess. The retaining member is configured to retain the shuttle within the barrel.