Ball-Lock Retainer Constraint Member for Punch Bounce Control

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Solution Overview

Problem

Conventional ball-lock retainers experience issues with ball bounce and vibration during stamping operations, particularly when working with thick or hard materials, leading to burr formation, difficulty in punch removal, and increased likelihood of locking ball fatigue and breakage.

Innovation Solution

Incorporating a constraint member, such as a set screw, that projects into the ball-lock passage to mechanically constrain the locking ball's movement, thereby controlling axial movement and reducing vibration during stamping operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a spring-loaded locking ball is used to retain the punch, then the punch can be easily and rapidly removed and replaced, but the locking ball experiences bounce and vibration during stamping operations leading to burr formation and fatigue

Engineering Contradiction:

Improveease of punch removalVSAvoidlocking ball stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The locking mechanism is segmented into two independent functional components: the spring-loaded locking ball for retention/release operations and the constraint member for vibration control during stamping. This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The constraint member acts as an intermediary element that mediates between the locking ball and the punch, mechanically constraining the locking ball's movement to prevent bounce and vibration while allowing the locking ball to maintain its spring-loaded retention function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If the compression spring applies biasing force to the locking ball, then the locking mechanism remains engaged during stamping, but the cyclic compression and tension cause the locking ball to bounce and vibrate

Engineering Contradiction:

Improvelocking forceVSAvoidball bounce and vibration

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The constraint member converts the harmful bounce and vibration motion of the locking ball into beneficial controlled movement. By mechanically constraining the locking ball within a defined range, the constraint member transforms the potentially damaging cyclic motion into a controlled, limited movement that maintains locking engagement while preventing burr formation and fatigue.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Duration of action of moving object

If the locking ball is allowed to move axially during stamping, then the spring can maintain engagement, but burrs form on the locking ball and ball seat

Engineering Contradiction:

Improveengagement durationVSAvoidsurface quality

Core Design Contradiction:

Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The constraint member applies localized control to the locking ball's movement, restricting axial displacement only in the regions that cause burr formation on the ball seat and locking ball surfaces, while allowing sufficient movement to maintain spring engagement throughout the stamping cycle.

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

The constraint member significantly reduces burr formation, locking ball fatigue, and punch pull-out, while maintaining the locking mechanism's stability and reducing wear on the punch's cutting edge, enhancing the reliability and longevity of the retainer.

Implementation Method 1

a spring-loaded locking ball, which is disposed in the secondary passageway and is spring biased by a compression spring within the secondary passage

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

A constraint member is disposed in the third passage. The constraint member has a portion configured to project from the third opening into the second passage such that the portion of the constraint member at least partially occludes the second passage to thereby constrain axial movement of the locking member within the second passage

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentUS9327335B2Ball-lock retainers and methods for controlling ball bounce in a ball-lock retainer

Publication Date: 2016.05.03 DAYTON PROGRESS CORP

AI summary

Retainers for holding tools and methods for controlling the motion of a locking member, such as a resiliently-biased locking ball, in a retainer. The locking member is disposed in a passage that intersects another passage configured to receive the tool. A portion of the locking member has a contacting relationship with the tool in order to hold the tool within its passage. The retainer further includes a constraint member, which may be a threaded member or a non-threaded member, that occludes the passage containing the locking member. During a stamping operation using the tool, the constraint member mechanically constrains motion of the locking member within its passage by contact with the locking member.