Controlled Thread Clamp for Reliable Seam Initiation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing sewing machines face challenges in reliably forming a secure seam start, particularly with lockstitch machines, due to inconsistent entanglement of upper and lower threads, especially at the beginning of the seam, which affects reproducibility across different materials and thicknesses.

Innovation Solution

A controlled thread clamp with a controllable actuating mechanism that can be closed and opened at specific times to ensure reliable thread clamping and release, using drive means like pneumatic or electric drives, and adjustable timing to coordinate with the sewing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional thread clamp is used, then the seam formation is improved, but the reliability of seam start is still insufficient

Engineering Contradiction:
Improvereliability of seam startVSAvoidcomplexity of thread clamp control
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The thread clamp is activated before the needle begins stitching to pre-clamp the threads together at the puncture point. This preliminary action ensures that the threads are properly positioned and tensioned before the actual seam formation begins, eliminating the unreliable thread entanglement that occurs with traditional clamps that only activate during stitching.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system monitors the stitching process and automatically activates the thread clamp based on detected conditions such as material thickness, thread type, and needle position. This feedback mechanism allows the system to adapt the clamping action to specific sewing conditions, ensuring reliable seam start without requiring manual intervention or complex mechanical adjustments.

Inventive Principle:
Principle #23Feedback

2Reliability

If the thread clamp is activated early, then reliable seam formation is achieved, but the threading process becomes more complex

Engineering Contradiction:
Improvereproducibility of seam formationVSAvoidease of threading
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The thread clamp is designed to automatically grasp and hold the threads together at the puncture point without requiring manual threading adjustments. The clamp activates autonomously when the needle approaches the material, maintaining consistent thread tension and positioning throughout the stitching process, which eliminates the need for operators to manually adjust threading for different materials.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The thread clamp incorporates a dynamic control mechanism that adjusts the clamping force and activation timing based on real-time feedback from the stitching process. This dynamic adjustment allows the system to maintain optimal thread tension regardless of material variations, ensuring reproducible seam formation while keeping the threading process simple through automated adaptation.

Inventive Principle:
Principle #15Dynamics

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 provides reproducible and secure seam formation by ensuring consistent thread tension and clamping, improving the reliability of seam initiation and overall sewing process, especially at the start of the seam.

Implementation Method 1

an operable thread clamp (29), which can be closed for clamping by means of a controllable actuating means (36, 38)

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

The thread clamp is opened by means of a spring element when the actuating means has released it

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2714979B1Sewing machine having a thread clamp
Publication Date: 2016.12.28 PFAFF INDUSTRIESYSTEME & MASCH GMBH
  • EP2714979B1 patent drawingFigure 1
  • EP2714979B1 patent drawingFigure 2
  • EP2714979B1 patent drawingFigure 3

AI summary

The invention relates to seam producing means for a sewing machine, comprising thread guiding means such as a needle and/or a gripper for guiding at least one thread provided for producing a seam, and comprising a thread clamping device having a thread clamp (29) into which a thread can be inserted, clamped, and guided out again in particular for producing a start of a seam. The aim of the invention is to achieve an improvement with respect to reliable seam production even at the start of a sewing process. In order to achieve said aim, a thread clamp (29) that can be actuated for such seam producing means can be closed by means of a controllable actuator for clamping and/or opened by means of the actuator.