Wire Thread Insert Installation Spindle with Independent Axial Actuation

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Solution Overview

Problem

Existing installation processes for wire thread inserts in threaded holes lack efficiency and automation, requiring manual coordination and multiple components to function effectively, leading to increased cycle times and coordination efforts.

Innovation Solution

An automatic installation device with a rotating drive unit, axially displaceable setting spindle, pneumatic actuators, and a tool chuck, allowing for independent control of rotary and linear movements to simplify the installation process and reduce coordination efforts, enabling seamless transition between screwing and actuation steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a rotating drive unit with gear train and hollow-cylindrical mandrel is used to install wire thread inserts, then the installation process can be automated, but the device complexity increases due to multiple components requiring coordination

Engineering Contradiction:
Improveautomation of wire thread insert installationVSAvoidcomplexity of drive unit and mandrel system
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The installation device is divided into functionally independent segments: a rotating drive unit for screwing the insert, a linear actuator for axial displacement, and a punching device for breaking the spigot. Each segment operates independently with its own drive mechanism, eliminating the need for complex coordinated control of a single integrated system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses dynamic, independently controllable actuators that can be activated in sequence rather than a static mechanical linkage system. The linear actuator and punching device can be controlled separately and at different times, allowing flexible adaptation to various installation steps without requiring complex mechanical coordination.

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple components (rotating drive unit, gear train, hollow-cylindrical mandrel, punching device) are used together, then the installation process is more comprehensive, but the coordination effort and cycle time increase

Engineering Contradiction:
Improvecompleteness of installation processVSAvoidcycle time of installation process
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The wire thread insert is pre-loaded onto the mandrel before the installation process begins. The linear actuator is pre-positioned to receive the mandrel. This preliminary preparation eliminates the need for complex real-time coordination during the actual installation, as components are already in their required states and positions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The rotating drive unit automatically screws the wire thread insert into the threaded hole through its own rotational motion, without requiring separate linear displacement mechanisms. The system uses the screwing action itself to achieve both rotational engagement and axial positioning, reducing the need for additional coordinated components.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the setting spindle is offset-coupled with the actuator, then the actuator can displace the setting spindle axially, but the structural complexity increases

Engineering Contradiction:
Improveindependent control of axial displacementVSAvoidstructural complexity of connection
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The linear actuator is extracted as a separate, independent component from the rotating drive unit. It is offset-coupled to the setting spindle, allowing it to provide axial displacement without being integrated into the rotational mechanism. This separation simplifies the control logic, as each actuator can be independently activated without coordinating with the other.

Inventive Principle:
Principle #2Taking out (Extraction)

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 automatic installation device significantly reduces cycle times by separating the delivery and rotating installation processes, allowing simultaneous use of multiple drive units to enhance the effectiveness of wire thread insert installation, improving efficiency and automation compared to manual systems.

Implementation Method 1

a first pneumatic cylinder (30) with a piston (32), the direction of action of which is oriented parallel to the longitudinal direction of the setting spindle (10)

Methodology Applied
Scientific EffectPneumatic pressure: Pressure Increase

Implementation Method 2

A threaded connection between the mandrel and an internally threaded sleeve converts rotation of the motor into linear installation movement of the mandrel into the threaded bore

Methodology Applied
Scientific EffectThreaded connection: Screw

Implementation Method 3

The outer diameter of the cylindrical helix of the wire thread insert must be selected to be slightly larger than the inner diameter of the component's receiving thread. In this way, it is ensured that the wire thread insert is firmly seated after installation in the receiving thread due to the elastic recovery of the wire thread insert

Methodology Applied
Scientific EffectElastic recovery: Elastic Recovery

Data Source

PatentEP3954503B1Installation device for an installation tool for a wire thread insert and installation method
Publication Date: 2023.06.07 BOLLHOFF VERBINDUNGSTECHNIK GMBH
  • EP3954503B1 patent drawingFigure 1
  • EP3954503B1 patent drawingFigure 2a)~2c)
  • EP3954503B1 patent drawingFigure 3

AI summary

An installation machine that can be connected to an installation tool for a wire thread insert to install the wire thread insert in a threaded bore, wherein the installation machine has the following features: a rotating drive unit that provides a rotary motion switchable between a first and a second direction of rotation, an axially displaceable hollow cylindrical setting spindle in rotary coupling with the rotating drive unit, such that during a transmission of a rotary motion from the drive unit to the setting spindle, the setting spindle can be displaced in the longitudinal direction independently of the rotary motion, a first pneumatic cylinder with an axially movable piston whose direction of action is oriented parallel to the longitudinal direction of the setting spindle and which is offset coupled to the setting spindle, so that the setting spindle can be displaced axially by the pneumatic cylinder, an axially displaceable actuating mandrel,which is arranged inside the hollow cylindrical setting spindle and driven in a non-rotating manner, and a tool chuck via which the installation tool for a wire thread insert can be connected to the setting spindle.