Die Head Retaining Mechanism With Cam-Locked Jaws

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Solution Overview

Problem

Existing thread cutting machines require high effort and time for installing and removing die heads due to cumbersome locking mechanisms, such as spring rings and retaining rings, which also lose stiffness with use, necessitating frequent replacements.

Innovation Solution

A die head retaining mechanism featuring a face gear with equidistant locking jaws, a compression spring, and a drive ring with cam profiles, allowing for easy installation and removal of the die head by rotating the drive ring to compress the spring and radially move the locking jaws, reducing the force required for engagement and disengagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring ring is used to lock the die head, then the die head can be retained in the power drive, but a higher effort is required for installing or removing the die head

Engineering Contradiction:
Improvedie head retentionVSAvoiddie head installation effort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism uses a movable locking jaw that can shift between locked and unlocked positions. The jaw is biased by a spring to engage with the die head, and rotation of the drive ring moves the jaw radially to release the lock, making installation and removal dynamic and easy

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism is divided into separate functional components: the locking jaw, the drive ring with cam profiles, and the compression spring. This segmentation allows each component to perform its specific function efficiently while working together as a integrated system

Inventive Principle:
Principle #1Segmentation

2Reliability

If a spring ring is used to lock the die head, then the die head can be retained in the power drive, but the spring ring loses stiffness with use requiring frequent replacements

Engineering Contradiction:
Improvedie head retentionVSAvoidspring ring service life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The design uses a simple compression spring that can be easily replaced if needed, but the overall mechanism is designed so the spring maintains its properties. The spring is positioned in a groove and works with the drive ring to provide consistent locking force throughout its service life

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The compression spring automatically maintains the locking jaw in the engaged position, and the mechanism self-regulates the locking force. The spring is preloaded and positioned to ensure consistent performance without requiring manual adjustment during operation

Inventive Principle:
Principle #25Self-service

3Reliability

If a retaining ring is used to lock the die head, then the die head can be retained in the power drive, but greater time is required for installing or removing the die head

Engineering Contradiction:
Improvedie head retentionVSAvoiddie head installation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The locking and unlocking action is achieved through periodic rotation of the drive ring. Each rotation cycles the locking jaw between engaged and disengaged states, allowing rapid repeated installation and removal operations without manual intervention

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The manual operation of traditional retaining rings is replaced with a cam-driven mechanical system. The cam profiles on the drive ring automatically move the locking jaw radially, substituting complex manual manipulation with simple rotational motion

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution significantly reduces the effort needed for installing and removing die heads, enhances operational efficiency, and minimizes the need for frequent replacements of locking components by providing a reliable and efficient locking mechanism.

Implementation Method 1

A die head retaining mechanism features a face gear with equidistant locking jaws, a compression spring, and a drive ring with cam profiles, allowing for easy installation and removal of the die head by rotating the drive ring to compress the spring and radially move the locking jaws

Methodology Applied
Scientific EffectCompression spring: Spring

Data Source

PatentEP2879829B1Power drive with a threading die head retaining mechanism
Publication Date: 2022.11.30 EMERSON ELECTRIC CO
  • EP2879829B1 patent drawingFigure 1
  • EP2879829B1 patent drawingFigure 2~2b
  • EP2879829B1 patent drawingFigure 3

AI summary

A die head retaining mechanism for installing or removing a die head (301) in a power drive (300) for thread cutting operations features a chuck with simultaneously-acting locking jaws (230), moving radially, the jaws movement actuated by substantially spiral grooves (276) acting as cam profiles. A face gear (220) has at least the locking jaws (230) disposed in a slot (225) provided on the face of the face gear oriented away from the housing (310). The mechanism also comprises a drive ring (270) having a collection of cam profiles (276) to control the movement of the locking jaws (230). The mechanism also comprises at least one compression spring (250) disposed in a corresponding groove (222) on the face gear (220). The compression spring (250) is preloaded to keep the locking jaws (230) in a locked position. The mechanism also comprises a bearing (240) between the housing (310) and the face gear (220). The bearing (240) is locked in place by a retaining ring (260). A locking plate (280), spring washers (290), and screws (294) are used to secure the assembly of the die head retaining mechanism on the power drive (300).