Wave-Spring Bar Guide With Bushings for Vibration Damping

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Solution Overview

Problem

Existing bar loading apparatuses for machine tools, such as lathes, cause surface damage to slender bars due to intense flexural vibrations and direct contact with helical springs, leading to suboptimal processing quality.

Innovation Solution

A wave-spring element with alternating groups of turns of different diameters and intermediate turns forming a sinusoidal profile, incorporating bush means with widened edge portions to prevent direct contact and sliding, ensuring stable positioning and smooth contact with the bar.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If helical springs with narrow-diameter turns are used to contain and guide the bar, then the bar is effectively contained and guided during rotation, but the direct contact and sliding between the turns and the bar cause surface damage to the bar

Engineering Contradiction:
Improvebar containment and guidance effectivenessVSAvoidsurface damage to bar
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary layer (coating or bushing) between the helical spring turns and the bar surface. This intermediary material prevents direct metal-to-metal contact and sliding, thereby eliminating surface damage while maintaining the containment and guidance function of the spring turns.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the surface properties of the spring turns by applying coatings or using bushings with different material characteristics. This changes the friction and contact properties between the spring and bar, reducing harmful sliding effects while preserving the mechanical containment function.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the wave-spring element uses turns of different diameters to dampen vibrations, then flexural vibrations are effectively reduced, but the structure becomes more complex

Engineering Contradiction:
Improvevibration damping effectivenessVSAvoidspring structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wave-spring element is segmented into distinct zones with different turn diameters. Each zone serves a specific function: larger diameter turns provide structural support and flexibility, while smaller diameter turns provide containment and vibration damping. This segmentation achieves effective vibration control through a structured variation in geometry.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a wave-spring design with varying curvatures along its length. The sinusoidal profile creates alternating regions of different radii of curvature, which naturally dampen flexural vibrations through geometric means while maintaining structural integrity and flexibility.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

Effectively dampens flexural vibrations while preventing surface damage to the bars, resulting in higher quality processed products by eliminating localized high-pressure contact zones.

Implementation Method 1

The wave-spring element serves to contain and guide a bar during its rotation and advancement towards the machine tool and acts to dampen the flexural vibrations to which the bar is subjected during its rotation

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3846956B1Wave-spring element for apparatuses for loading and advancing bars to machine tools
Publication Date: 2023.11.08 CUCCHI GIOVANNI & C
  • EP3846956B1 patent drawingFigure 1
  • EP3846956B1 patent drawingFigure 2~3
  • EP3846956B1 patent drawingFigure 4~5

AI summary

A wave- spring element (1) for a bar loader apparatus comprises a plurality of turn elements (2) arranged adjacent to one another and defined by first groups (G1) of turn elements with a greater diameter (D1) and second groups (G2) of turn elements with a lesser diameter (D2): the first groups (G1) and the second groups (G2) alternate along a longitudinal axis (AL), interspersed with intermediate turns (2'), so as to define a surface (S) with sinusoidal profile; the plurality of turn elements (2) is configured to contain and guide a bar (B) to a machine tool, such as a lathe, and for dampening the stresses and flexural vibrations to which the bar itself (B) is subjected during its own rotation; there are provided bush means (3) arranged inside each second group (G2) of turns having a lesser diameter (D2) and configured to come into contact with, and receive inside, respective portions of the bar (B) to avoid contact with, and sliding with respect to, said turns (2). A method is also provided for obtaining the aforementioned wave- spring element (1) including bush means (3) according to the invention.