Sliding Jaw Bar Centering for Stable Lathe Feeding

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Solution Overview

Problem

Existing centering devices for bar loaders in automatic lathes face challenges such as high oscillation of bars due to rotation and misalignment, leading to vibration issues, difficulty in accommodating bars with varying diameters, and complex maintenance processes, which result in reduced machining quality and increased wear.

Innovation Solution

A centering device with adjustable jaws mounted on a sliding slider, driven by elastic means, allowing for radial movement to accommodate bars of different diameters and easy assembly/disassembly, ensuring stable support and reduced oscillation without obstructing the bar pusher's passage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the channel diameter in the centering device is made small to reduce lateral play, then bar stability is improved, but the bar pusher cannot pass through the centering device

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

Solution Approach 1:

The centering device incorporates a movable jaw assembly that can dynamically adjust its position between two states: a first position where the jaws define a small channel diameter for stabilizing the bar, and a second position where the jaws are retracted to allow the bar pusher to pass through. This dynamic adjustment resolves the contradiction by making the channel diameter variable rather than fixed, allowing the system to optimize for bar stability during machining while enabling pusher access during feeding operations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of channel diameter from a fixed value to a variable parameter that can be adjusted between two states. The movable jaw assembly, actuated by springs and guided by cam surfaces, enables the channel diameter to be reduced when bar stabilization is needed and increased (by jaw retraction) when the bar pusher needs to pass through, thus resolving the technical contradiction through parameter variation

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the centering device structure is made complex to accommodate variable bar diameters, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improveaccommodation of variable bar diametersVSAvoidcentering device structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The movable jaw assembly serves multiple functions: it provides adaptability to accommodate bars of different diameters by adjusting the jaw position, maintains bar stability during machining, and enables passage of the bar pusher by retracting. This multi-functionality reduces the need for multiple separate devices or complex adjustment mechanisms, as the single jaw assembly handles diameter variation, stabilization, and pusher access requirements

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

Solution Approach 2:

The jaw assembly is designed with spring elements and cam-guided movement that enable automatic adjustment. The springs provide the necessary force for jaw movement and positioning, while the cam surfaces guide the movement trajectory, reducing the need for complex external actuation mechanisms and simplifying the overall device structure while maintaining adaptability

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If the centering device is designed to hold bars precisely, then manufacturing precision is improved, but maintenance difficulty increases

Engineering Contradiction:
Improvebar centering precisionVSAvoidjaw assembly maintenance
Core Design Contradiction:
Manufacturing precisionVSEase of repair

Solution Approach 1:

The centering device is segmented into modular components, with the jaw assembly being a distinct, separable unit from the main device body. The jaws are mounted on movable supports that can be independently accessed and adjusted. This segmentation allows the jaw assembly to be maintained, adjusted, or replaced without disassembling the entire centering device, thus maintaining precise centering capability while simplifying maintenance operations

Inventive Principle:
Principle #1Segmentation

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 stabilizes bars of various diameters, reduces oscillation, and facilitates easy maintenance, enhancing machining quality and productivity while accommodating larger diameter bars without compromising on precision or longevity.

Implementation Method 1

a supporting slider (20) slidable along the channel (11) against the action of elastic means (25) in response to a thrust on the jaws (17) towards said outlet end (16)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3423222B1Radial centering device for bar loaders in automatic lathes
Publication Date: 2023.06.07 DREHMAG SRL
  • EP3423222B1 patent drawingFigure 1~2
  • EP3423222B1 patent drawingFigure 3~4
  • EP3423222B1 patent drawingFigure 5

AI summary

A centering device (10), intended to be used in an automatic bar loader for a lathe, comprises a channel (11) with a rectilinear axis (12) intended for the passage of a bar from the loader to the lathe. The centering device comprises mobile jaws (17) on the sides of the channel (11) for defining an adjustable through-aperture inside the channel. The jaws (17) are mounted in a supporting slider (20) so as to be slidable in the supporting slider (20) radially relative to the channel (11) and the supporting slider (20) is slidable along the channel (11) against the action of elastic means (25) in response to a thrust on the jaws directed towards the said outlet end (16). The slider may thus move between a first position closer to the inlet end (15), in which the jaws are in a first position projecting into the channel with their operative surface (18), and a second position closer to the outlet end (16), in which the jaws may slide inside the supporting slider so as to move radially away from the said position projecting into the channel. A loader with such a centering device is also described.