Robot Joining Unit Locking Pressure Piece Against Tilt

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Solution Overview

Problem

Articulated-arm robots face challenges in maintaining orthogonal alignment during friction welding due to tilting of friction welding elements and loss of engagement with drive structures, leading to unreliable component joining.

Innovation Solution

A joining unit for articulated-arm robots that includes a feed unit with a pressure piece and a coupling unit featuring a blocking unit to apply axial force, preventing relative movement until a set blocking force is reached, and a release device to reduce or eliminate this force once the joining element contacts the component, ensuring precise alignment and force transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a friction welding process is used with an articulated robot arm, then the joining process can be automated, but the friction welding element tilts and loses engagement with the drive structure

Engineering Contradiction:
Improveautomation of joining processVSAvoidengagement reliability
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent introduces a dynamic locking mechanism that actively maintains the axial position of the friction welding element during the automated joining process. The locking mechanism includes a locking element that can engage and disengage based on process requirements, allowing the system to maintain reliability while remaining automated. This resolves the contradiction by adding dynamic control to prevent tilting and loss of engagement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism acts as an intermediary between the feed unit and the friction welding element. It provides an additional degree of control that ensures the joining element remains properly engaged with the drive structure during automated operation, preventing tilting while maintaining the automation benefit.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If axial force is applied during friction welding, then the joining process can proceed, but the friction welding element tilts away from orthogonal alignment

Engineering Contradiction:
Improveaxial setting forceVSAvoidalignment precision
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The locking mechanism dynamically controls the application and release of axial force. By locking the pressure piece in specific positions, it prevents unwanted tilting movements while allowing controlled axial movement when needed for the joining process. This maintains orthogonal alignment precision while enabling necessary force application.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism applies a preliminary counteracting force to prevent tilting before it occurs. By engaging the locking element in advance, the system prevents deviation from orthogonal alignment while maintaining the ability to apply necessary axial force for the joining process.

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of operation

If the pressure piece is allowed to move freely during pre-tensioning, then the joining element can be positioned, but relative movement cannot be prevented until locking force is reached

Engineering Contradiction:
Improvepositioning easeVSAvoidpositioning precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The locking mechanism provides dynamic control over the pressure piece movement. It allows free movement during positioning phases for ease of operation, then engages to lock the position with high precision when required. This resolves the contradiction by making the system adaptable to different operational phases.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism is designed to engage at a predetermined locking force threshold. This preliminary action ensures that positioning can occur freely first, then automatically locks when the appropriate force is reached, achieving both ease of positioning and precision control.

Inventive Principle:
Principle #10Preliminary action

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

This solution prevents tilting of the joining element during the process, maintaining alignment and ensuring a reliable, precise joining process by maintaining constant tension and preventing misalignment, thus enhancing the quality of the joining result.

Implementation Method 1

the coupling unit is designed as a coil spring that supports the pressure piece relative to the feed unit. When the pressure piece rests on the component, it exerts a spring force on the component or component assembly

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

the cylinder is designed as a pneumatic cylinder, which, above a certain force exceeding the preset locking force, allows relative movement of the pressure piece due to air compression

Methodology Applied
Scientific EffectAir compression: Compression

Data Source

PatentEP3638464B1Device for compensating joining motions
Publication Date: 2021.12.08 EJOT GMBH & CO KG
  • EP3638464B1 patent drawingFigure 1~2
  • EP3638464B1 patent drawingFigure 3~4
  • EP3638464B1 patent drawingFigure 5~7

AI summary

The invention relates to a joining unit (10, 40) for an articulated arm robot (12, 44) for joining a component (24, 58) with a joining element (28, 60) by applying an axial force. The joining unit (10, 40) comprises a base element (14, 42) for connecting to an articulated arm robot (12, 44). The base element (12, 42) is connected to an advancing unit (13, 46), which can be moved relative to the base element (14, 42) in an axial direction in and against a setting direction. The advancing unit (13, 46) is connected to a setting device (16, 54), which can be moved together with the advancing unit (13, 46). Furthermore, a pressure piece (26, 50) mounted for movement relative to the advancing unit (13, 46) in and against the setting direction is connected to the advancing unit (13, 46) by means of a coupling unit (17, 48). The invention is distinguished in that the coupling unit (17, 48) comprises a blocking unit (18, 56), which, starting from a predefined axial blocking position, prevents motion of the pressure piece (26, 50) relative to the advancing unit (13, 46) against the setting direction so long as the advancing force is less than the set blocking force. The blocking unit comprises a release device (20, 62), by means of which the relative motion of the pressure piece (26, 50) against the setting direction is enabled.