Multipod Machine Tool Locking Structure for High Rigidity Machining

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Solution Overview

Problem

Machine tools with low rigidity and limited processing space, leading to low process forces and long processing times, are inadequate for efficient machining and measurement of larger workpieces.

Innovation Solution

A machine tool with a multipod drive that becomes mechanically overdetermined when braced, increasing stiffness by at least 1.5 times in the braced state compared to the unstressed state, allowing for higher forces and improved rigidity through a controlled locking mechanism of support and drive elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the machine tool uses a multipod drive with mechanical overdetermination to increase rigidity, then the stiffness increases by at least 1.5 times, but the device complexity increases due to additional support elements and locking mechanisms

Engineering Contradiction:
ImprovestiffnessVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The multipod drive system dynamically transitions between stressed and unstressed states through the locking mechanism. The support elements can be locked to create mechanical overdetermination for high rigidity during machining, or unlocked to allow flexible positioning and movement, enabling the system to adapt its structural characteristics based on operational requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the mechanical parameter of rigidity by transitioning the multipod drive between locked and unlocked states. The locking mechanism alters the boundary conditions of the support elements, transforming the system from a flexible configuration during positioning to a rigid configuration during machining operations

Inventive Principle:
Principle #35Parameter changes

2Force

If the machine tool is designed for high rigidity with mechanical overdetermination, then processing forces can be increased, but the processing space becomes more limited

Engineering Contradiction:
Improveprocess forcesVSAvoidprocessing space
Core Design Contradiction:
ForceVSArea of stationary object

Solution Approach 1:

The multipod drive system dynamically adjusts its rigidity characteristics through the locking mechanism, being flexible during positioning to access large work areas, then becoming rigid during machining to withstand high process forces, thus resolving the contradiction between processing space and force capability

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the machine tool uses a hexapod drive with fine adjustment device, then positioning accuracy is improved, but the processing space becomes smaller

Engineering Contradiction:
Improvepositioning accuracyVSAvoidprocessing space
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The system uses the locking mechanism to dynamically switch between a flexible state for maximum processing space access and a rigid locked state for high-precision machining, maintaining both large work area capability and positioning accuracy without compromise

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3628439B1Machine tool
Publication Date: 2022.01.19 PICUM MT GMBH
  • EP3628439B1 patent drawingFigure 1
  • EP3628439B1 patent drawingFigure 2
  • EP3628439B1 patent drawingFigure 3

AI summary

The invention relates to a machine tool (10) comprising (a) a tool head frame (16), (b) a tool head (18), (c) an axis unit (20) for positioning the tool head (18) to a predefinable position, and (d) a motion device (28) for moving the tool head frame (16). According to the invention, the motion device (28) comprises (e) a machine frame (12) and (f) a multipod drive (14) which (i) has at least three drive elements (24), (ii) is arranged in the power flow between the machine frame (12) and the tool head frame (16), and (iii) has at least two support elements (26) that can be brought into a locked position, (iv) wherein the multipod drive (14) is mechanically overdetermined by the support elements (26) and the drive elements (24).