Grinding Machine Control Disc for Tap Relief-Grinding

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Solution Overview

Problem

Existing methods for back-grinding cutting teeth of screw taps and thread formers are inefficient due to direct mechanical scanning, which leads to sluggish operation and the need for costly, high-precision control disks with fixed undercut contours, requiring frequent replacement and storage of multiple parts to accommodate different relief contours.

Innovation Solution

A method employing a rotating oscillating movement over a limited circumferential angle of the control contour, with adjustable rotational speeds and a control comb design, allowing for variable undercut contours without the need for replacing high-precision parts, using a grinding machine with a rotating control disc and oscillating drive to define specific undercut profiles through mechanical, optical, or electronic scanning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If direct mechanical scanning with control disks is used, then the undercut contour can be precisely formed, but the operation becomes sluggish and requires frequent replacement of high-precision parts

Engineering Contradiction:
Improveundercut contour precisionVSAvoidgrinding operation speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the traditional mechanical scanning system with control disks with a light-based scanning system. A light source projects a light pattern onto a control surface, and a light receiver detects the light to generate control signals. This substitution eliminates the need for mechanical contact and high-precision mechanical parts, thereby increasing operational speed while maintaining contour precision.

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

Solution Approach 2:

The patent uses a light pattern that represents the desired undercut contour as a digital or optical copy of the control information. Instead of physically scanning a mechanical control disk, the light pattern is projected and detected, allowing the system to reproduce the contour information without mechanical wear or replacement needs, thus improving productivity while preserving manufacturing precision.

Inventive Principle:
Principle #26Copying

2Adaptability or versatility

If multiple control disks with different undercut contours are used, then different relief contours can be formed, but the cost of storing and replacing high-precision parts increases

Engineering Contradiction:
Improvevariety of relief contoursVSAvoidnumber of control parts to store
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs a single control surface that can display multiple different light patterns, each representing a different undercut contour. The light-based system can be reprogrammed or reconfigured to project different patterns without requiring physical replacement of control disks. This universal approach allows the system to handle multiple relief contour requirements with one device, reducing storage and replacement complexity.

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

Solution Approach 2:

The control surface in the patent is designed to be dynamically reconfigurable through optical means. Instead of static control disks that must be physically replaced, the light pattern can be changed dynamically to represent different undercut contours. This dynamic capability provides adaptability for various relief contours without increasing the number of physical parts to store or manage.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If control disks are replaced frequently to accommodate different undercut contours, then adaptability is improved, but time is lost during replacement processes

Engineering Contradiction:
Improveability to form different undercut contoursVSAvoidtime for control disk replacement
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

By replacing the mechanical control disk system with an optical light-based system, the patent eliminates the physical replacement process entirely. The light patterns can be changed instantaneously through electronic control or reconfiguration, allowing the system to adapt to different undercut contours without any time-consuming mechanical intervention. This substitution directly addresses the time loss issue while maintaining full adaptability.

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

Solution Approach 2:

The patent allows the light patterns representing different undercut contours to be prepared and stored in advance in the system's memory or control mechanism. When a different contour is needed, the system can immediately switch to the pre-prepared light pattern without requiring any physical preparation or replacement action. This preliminary preparation of control information eliminates replacement time while preserving adaptability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP1991392B1Method for relief-grinding the cutting teeth of taps, thread formers, and similar tools, and grinding machine for carrying out said method
Publication Date: 2010.05.12 ERWIN JUNKER MASHINENFABRIK GMBH
  • EP1991392B1 patent drawingFigure 1
  • EP1991392B1 patent drawingFigure 2
  • EP1991392B1 patent drawingFigure 3

AI summary

In prior art, an additional radial inward movement that is performed in accordance with a rotating cam disk is imparted on the grinding disk in order to relief-grind the cutting teeth and the chamfer of taps and the cutting teeth of thread formers. The invention relates to a cam disk (11) which can be rotated about an axis A and is provided with a control cam (12). Said control cam (12) forms a group of curves according to a large number of possible undercut contours on the grinding teeth of the tap or thread former, which are to be relief-ground. In order to obtain a specific undercut contour on a cutting tooth, a limited angle of rotation a is selected from the control cam (12). Said area is mechanically, optically, or electronically scanned by means of a scanning device (13). To this avail, the cam disk (11) performs an oscillating rotary movement only above the selected section of the control cam (12) (arrow indicating the direction of rotation 15). Relief-grinding of the cutting tooth is completed once a fore-and-aft movement has been performed, and the grinding disk returns to the starting position thereof. The result of the scan is transmitted to an electronic control device via a signal line (14).