Spring-Biased Ball Bit Retention Device for One-Handed Operation

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Solution Overview

Problem

Conventional bit retention devices for power and hand tools often require operators to use both hands for inserting and removing tool bits, as they necessitate actuating a sleeve or collar during these processes, which can be cumbersome and inefficient.

Innovation Solution

A bit retention device featuring a spring-biased ball mechanism with a ramped actuator sleeve that allows for one-handed operation by using a shallow and steep ramp configuration to guide the ball into and out of a bit's groove, enabling easy insertion and removal without needing to manually actuate the sleeve during the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional detent ball mechanism with sleeve actuation is used, then bit retention is secure, but bit insertion and removal require two hands and are cumbersome

Engineering Contradiction:
Improvebit insertion and removal operationVSAvoidsleeve actuation mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts the actuation function from a separate sleeve component and integrates it directly into the ball mechanism. The ball itself now performs the actuation function through its interaction with the ramp surface, eliminating the need for a separate actuating sleeve and reducing overall device complexity while maintaining secure bit retention.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the retention function and actuation function into a single integrated mechanism. The ball serves dual purposes: retaining the bit through engagement with the groove and actuating the release mechanism through interaction with the ramp surface. This consolidation eliminates the need for separate components and simplifies the overall structure.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If a sleeve actuation mechanism is used for bit retention, then bit security is maintained, but operation speed is reduced due to manual actuation requirements

Engineering Contradiction:
Improvebit change speedVSAvoidtime for bit insertion and removal
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The ramp surface is pre-configured in a specific geometric configuration that automatically guides the ball through the necessary motion sequence. When force is applied to the ball, the ramp surface already positions the ball to engage the bit groove for insertion or to disengage for removal, eliminating the need for manual sleeve actuation and significantly reducing the time required for bit changes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ball mechanism serves itself by using the same ball that retains the bit to also perform the actuation function. The ball's interaction with the ramp surface automatically initiates and completes the bit insertion or removal process without requiring external manual intervention, thereby increasing productivity and reducing time loss.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If a simple detent ball mechanism is used, then device structure is simple, but rapid one-handed operation is not achieved

Engineering Contradiction:
Improveone-handed operation capabilityVSAvoidramped surface configuration
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The ramp surface is designed with specific local geometric characteristics - a shallow portion and a steep portion - that create different mechanical advantages at different stages of the ball's motion. This localized variation in surface geometry enables the simple ball mechanism to achieve complex one-handed operation functionality without requiring elaborate device structures, maintaining ease of manufacture while improving ease of operation.

Inventive Principle:
Principle #3Local quality

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

Facilitates rapid and easy insertion and removal of tool bits with a single hand, enhancing user convenience and efficiency by eliminating the need for simultaneous operation of the actuator sleeve, while maintaining secure bit retention.

Implementation Method 1

A bit retention device featuring a spring-biased ball mechanism with a ramped actuator sleeve

Methodology Applied
Scientific EffectSpring mechanism: Spring

Data Source

PatentEP2689895B1Bit retention device
Publication Date: 2017.03.08 BLACK & DECKER CORP
  • EP2689895B1 patent drawingFigure 1
  • EP2689895B1 patent drawingFigure 2
  • EP2689895B1 patent drawingFigure 3

AI summary

A bit retention device includes a shaft (112) having a sidewall defining a hexagonal cavity (114) extending from a front end (124) thereof and a ball groove (128) extending through the sidewall and communicating with the hexagonal cavity. A ball (126) is disposed in the ball groove (128) and a ball spring (130) engages the ball (128) and biases the ball (126) toward the front end (124). An actuator sleeve (122) surrounding the shaft (112) includes an internal ramp (132) engaging the ball (126). A spring biased plunger assembly (118) is disposed in the bore (114) for biasing a bit (16) received in the bore (114) in a direction toward the insertion end (front end 124).