Headrest Support Rod Flow-Drilling Assembly to Reduce Welding Cost

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Solution Overview

Problem

Existing carrying devices for headrests, particularly in vehicles, face challenges in reducing manufacturing costs and time while ensuring safety and stability, as traditional welding methods are time-consuming and costly.

Innovation Solution

The use of flow drilling to create a form-fit and material connection between the support rods and crosspieces, allowing for a positive and cohesive attachment that reduces manufacturing time and costs, and enhances the structural integrity of the headrest.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional welding methods are used to connect support rods and crosspieces, then the connection strength and reliability are ensured, but the manufacturing time and costs increase

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the welding process (thermal/chemical system) with a flow drilling process that creates mechanical interlocking through plastic deformation. The flow drill bit deforms the crosspiece material to form tabs that mechanically lock into the support rod, eliminating the need for welding while maintaining connection strength and significantly reducing manufacturing time.

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

Solution Approach 2:

The invention changes the connection mechanism from thermal bonding (welding) to mechanical deformation (flow drilling). By altering the material state through controlled plastic deformation during the flow drilling process, the crosspiece material forms interlocking tabs that provide reliable mechanical connection without the time-consuming welding procedure.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional welding methods are used to connect support rods and crosspieces, then the connection strength and reliability are ensured, but the manufacturing costs increase

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the welding process with a flow drilling process that creates mechanical interlocking through plastic deformation. This substitution eliminates expensive welding equipment, consumables (electrodes, shielding gas), and skilled welder labor requirements, significantly reducing manufacturing costs while maintaining connection reliability through mechanical tab formation.

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

Solution Approach 2:

The flow drill bit is a disposable tool that creates the connection through controlled material deformation. Instead of investing in expensive, maintainable welding equipment and consumables, the invention uses relatively simple, replaceable drill bits that perform the connection function through a single-pass mechanical process, reducing overall manufacturing costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If flow drilling is used to create form-fit connection, then the manufacturing time and costs are reduced, but the connection complexity increases

Engineering Contradiction:
Improvemanufacturing timeVSAvoidconnection structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The flow drilling process segments the connection creation into distinct phases: initial drilling, material deformation, tab formation, and interlocking. This segmentation allows each phase to be optimized independently and simplifies the overall process control compared to welding, as the mechanical deformation naturally progresses through these stages without requiring complex thermal management or skill-based adjustments.

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

Flow drilling significantly reduces production time and costs while ensuring a strong, stable connection between the support rods and crosspieces, enhancing the safety and cost-effectiveness of the headrest assembly.

Implementation Method 1

high frictional heat is generated between the drill bit and the workpiece due to the high axial force in the longitudinal direction of the drill bit and the high speed that the temperature of the material that is in contact with the drill bit or in the heat-affected area increases a temperature of e.g. approx. 900°C rises

Methodology Applied
Scientific EffectFrictional heating: Friction

Data Source

PatentEP3199258B1Support device of a headrest, headrest and method for manufacturing a support device
Publication Date: 2020.04.29 GRAMMER AG
  • EP3199258B1 patent drawingFigure 1
  • EP3199258B1 patent drawingFigure 2
  • EP3199258B1 patent drawingFigure 3

AI summary

The invention relates, among other things, to a carrying device (13) for a headrest (10) with a first carrying rod (15a) and with a second carrying rod (15b) and with at least one carrying rod (15a) and the second carrying rod (15b) connecting them to one another Crossbar (16, 17), at least one crossbar (16, 17) being connected to the first support bar (15a) and to the second support bar (15b) by means of at least one fastener (27a, 27b, 29a, 29b). The special feature is that the attachment (27a, 27b, 29a, 29b) is formed by a form fit and/or bonded fit produced by flow drilling.