Segmented Pressing Arm Fixture for Uniform Workpiece Clamping

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Solution Overview

Problem

Conventional methods for fixing workpieces during friction stir welding, such as using hydraulic lever cylinders or whole plates, fail to uniformly distribute force, leading to deformation issues and reduced production efficiency, with surface profile tolerances exceeding 3mm.

Innovation Solution

A pressing device with a supporting member, pressing arm, and driving assemblies that provide long-distance compression and uniform force distribution, featuring adjustable gaskets and positioning members to stabilize the workpiece, allowing for precise and stable fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a hydraulic lever cylinder is used to press the perimeter of the battery tray, then the structure is simple, but the surface profile tolerance reaches about 8mm which is far beyond the desired 3mm

Engineering Contradiction:
Improvestructure simplicityVSAvoidsurface profile tolerance
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The pressing mechanism is divided into multiple pressing arms (first pressing arm, second pressing arm, third pressing arm) that can independently press different regions of the workpiece. Each pressing arm can be adjusted to apply force at specific locations, enabling precise control of surface profile tolerance while maintaining structural simplicity through modular design.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If a whole plate with strip-shaped holes is used to press the workpieces, then both perimeter and middle part are covered, but the pressing mechanism is heavy and turning over takes long time reducing production efficiency

Engineering Contradiction:
Improveworkpiece coverageVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The single heavy whole plate is segmented into multiple lighter pressing arms that can be independently positioned and adjusted. This segmentation reduces the weight of each component, enabling faster movement and turning over while still providing comprehensive coverage of the workpiece perimeter and middle parts through coordinated positioning of multiple arms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressing arms are designed to be adjustable and repositionable rather than fixed, allowing dynamic adaptation to different workpiece sizes and positions. This dynamic capability enables rapid reconfiguration between different pressing tasks, significantly improving production efficiency compared to a static whole plate system.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If a whole plate is used to press the workpieces, then it is a rigid body, but some workpieces are tightly pressed while others are not, resulting in non-uniform force distribution

Engineering Contradiction:
Improverigid body stabilityVSAvoidforce uniformity
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The rigid whole plate is divided into multiple independent pressing arms, each capable of independent adjustment. This allows each pressing arm to be individually positioned and force-adjusted according to the specific requirements of different workpiece regions, ensuring uniform force distribution across all workpieces while maintaining overall system stability through the coordinated rigid structure of multiple arms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each pressing arm can be independently adjusted to provide locally optimized pressing force based on the specific characteristics of different workpiece regions. This local adjustability ensures that areas requiring tighter pressing receive appropriate force while avoiding over-pressing in other areas, achieving uniform force distribution across the entire workpiece set.

Inventive Principle:
Principle #3Local quality

4Device complexity

If the whole plate cannot adjust the displacement of each workpiece, then the structure is simple, but deformation of workpieces after welding cannot be properly controlled

Engineering Contradiction:
Improveadjustment mechanism complexityVSAvoiddeformation control
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The pressing system is segmented into multiple independently adjustable pressing arms, each capable of individual displacement adjustment. This segmentation enables precise control of pressing displacement for each workpiece position, allowing proper compensation for workpiece deformation after welding while maintaining reasonable structural complexity through modular adjustable mechanisms.

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 achieves a surface profile tolerance of 3mm or less, enhancing production efficiency by ensuring uniform pressure and reducing deformation, while maintaining a compact structure.

Implementation Method 1

a pressing arm (2) connected to the first end (101) of the supporting member (1), wherein the pressing arm (2) is rotatable around the first end (101) of the supporting member (1) between a clamping state and a releasing state

Methodology Applied
Scientific EffectMechanical rotation:

Implementation Method 2

a pressing device for fixing a workpiece onto a worktable... a pressing arm (2) connected to the first end (101) of the supporting member (1)

Methodology Applied
Scientific EffectLeverage: Lever

Implementation Method 3

a locking assembly (5) arranged on the supporting member (1) and configured to lock the pressing arm (2) at a predetermined position when the pressing arm (2) is in the clamping state

Methodology Applied
Scientific EffectMechanical locking: Mechanical Fastener

Implementation Method 4

the pressing device may provide long-distance compression for the workpiece on the worktable. Moreover, the force applied onto the workpiece may be uniformly distributed, such that the compression is stable

Methodology Applied
Scientific EffectMechanical compression: Compression

Implementation Method 5

featuring adjustable gaskets and positioning members to stabilize the workpiece, allowing for precise and stable fixation

Methodology Applied
Scientific EffectMechanical positioning: Mechanical Fastener

Data Source

PatentEP4401918B1Pressing device for fixing workpiece onto worktable
Publication Date: 2026.03.18 ABB (SCHWEIZ) AG
  • EP4401918B1 patent drawingFigure 1
  • EP4401918B1 patent drawingFigure 2
  • EP4401918B1 patent drawingFigure 3

AI summary

Embodiments of the present disclosure provide a pressing device for fixing a workpiece onto a worktable, comprising: a supporting member extending in a first direction and comprising first and second ends opposite to each other in the first direction and first and second sides opposite to each other in a second direction normal to the first direction; a pressing arm connected to the first end of the supporting member and being capable of rotating between a closed state and an opened state with respect to the supporting member, wherein a space for receiving the workpiece is formed between the pressing arm and the supporting member when the pressing arm is in the closed state; a first driving assembly arranged on the first side of the supporting member and configured to drive the pressing arm to rotate between the closed state and the opened state with respect to the supporting member; a locking assembly arranged on the first side of the supporting member near to the second end of the supporting member and configured to lock the pressing arm when the pressing arm is in the closed state; and a second driving assembly coupled to the second side of the supporting member and configured to drive the supporting member to move in the second direction.