Jaw-Type Bar Centering with Variable Aperture for Automatic Lathes

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Solution Overview

Problem

Existing centering devices for bar loaders in automatic lathes face challenges in controlling the size of the guide channel, are difficult to assemble and disassemble, and generate high friction, leading to wear and maintenance issues, especially with bars of varying diameters and cross-sections.

Innovation Solution

A centering device with mobile jaws on sliding guides that adjust radially to define an adjustable aperture, allowing easy passage of the bar pusher and accommodating different bar diameters, and featuring a design for quick disassembly and replacement of worn parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the channel diameter is reduced to minimize lateral play, then bar oscillation is reduced, but the bar pusher cannot pass through the centering device

Engineering Contradiction:
Improvebar centering precisionVSAvoidbar pusher passage
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The centering device employs a dynamic aperture mechanism where the channel diameter is variable rather than fixed. The aperture can dynamically adjust its size: contracted to minimal diameter for precise bar centering, and expanded to allow passage of the bar pusher. This dynamic transformation resolves the contradiction between requiring small diameter for precision and large diameter for pusher access.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameter of channel diameter from a static value to a variable parameter. By controlling the aperture opening degree, the system transitions between two states: a contracted state with minimal lateral play for precision centering, and an expanded state with sufficient clearance for bar pusher passage. This parameter change enables the system to satisfy both contradictory requirements at different operational stages.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If fixed aperture centering devices are used, then structure is simple, but they cannot accommodate bars of different diameters

Engineering Contradiction:
Improvecentering device structureVSAvoidbar diameter accommodation
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The centering device transforms from a static fixed-aperture structure to a dynamic variable-aperture structure. The aperture can be adjusted in size to match different bar diameters, enabling the same device to accommodate multiple bar specifications. This dynamic capability provides versatility without requiring multiple fixed-aperture devices for different bar sizes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The variable aperture mechanism enables a single centering device to perform multiple functions: centering bars of different diameters, accommodating different bar pusher sizes, and adapting to various machining requirements. This multi-functionality replaces what would otherwise require multiple specialized fixed-aperture devices, achieving versatility while maintaining reasonable structural complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If adjustable aperture mechanisms are added, then bar diameter adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvebar diameter adaptabilityVSAvoidaperture control mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention implements aperture size as a controllable parameter that can be adjusted according to bar diameter requirements. By making the aperture dimension a variable parameter rather than a fixed design constant, the system achieves adaptability to different bar sizes while using a relatively simple adjustment mechanism compared to replacing entire centering devices.

Inventive Principle:
Principle #35Parameter changes

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 device effectively reduces bar oscillations, supports bars of varying diameters and cross-sections, and allows for easy maintenance by enabling rapid replacement of jaws, enhancing machining stability and productivity while minimizing downtime.

Implementation Method 1

a) an elastic element which pushes the jaws towards the retracted position so that when the bar pusher arrives at the centering device the jaws are automatically opened

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The jaws are mounted on respective sliding guides which guide the jaws for their sliding opening movement in a radial direction relative to the channel in response to a thrust on the thrust surfaces of the jaws in the channel axial direction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3423223B1Jaw-type centering device for bar loaders in automatic lathes
Publication Date: 2023.10.11 DREHMAG SRL
  • EP3423223B1 patent drawingFigure 1~2
  • EP3423223B1 patent drawingFigure 3~4
  • EP3423223B1 patent drawingFigure 5~6

AI summary

A centering device (10) is intended for use in an automatic bar loader for a lathe. The centering device (10) comprises a channel (11) with a rectilinear axis (12), intended for the passage of a bar from the loader to the lathe, and also comprises mobile jaws (17, 18) on the sides of the channel (11) for defining an adjustable through- aperture in the channel. The jaws (17, 18) are mounted on respective sliding guides (18, 20) which guide the jaws for their sliding opening movement in a direction radial to the channel (11) in response to a thrust on the jaws in the channel axial direction towards the outlet end (16). A loader with such a centering device is also described.