Toe-Closer Machine Curved Pressers for Tights Sewing

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Solution Overview

Problem

Existing machines for sewing the toes of tights often result in imperfect, aesthetically and functionally suboptimal products due to inability to achieve a 'round' sewing arc, limited variability in toe shape and length, and inefficiencies in production, leading to waste and reduced productivity.

Innovation Solution

An apparatus comprising a line-closer and toe-closer machine with synchronized rotating carousels, a blocking and transport device using deformable foils and actuators to precisely control the shape and curvature of the sewing progression, allowing for adjustable and uniform stitching of tights toes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional toe-closer machines are used to sew toes of tights, then basic toe closure is achieved, but a round sewing arc cannot be obtained resulting in poor quality and discomfort

Engineering Contradiction:
Improvesewing arc roundnessVSAvoidtoe comfort
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent employs curved guide surfaces and rounded positioning mechanisms in the toe-closer machine that guide the fabric through a circular arc path during sewing. This ensures the needle follows a perfect round arc, creating a uniform circular seam that is both aesthetically pleasing and comfortable for the wearer, directly resolving the inability of conventional machines to produce round sewing arcs.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention introduces adjustable parameters for controlling the sewing arc radius and curvature through movable guide elements and variable positioning mechanisms. These parameters can be modified to accommodate different toe sizes and desired seam curvatures, enabling precise control over the roundness and quality of the sewing arc while maintaining operational simplicity.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If fixed configuration toe-closing machines are used, then simple structure is maintained, but variability in toe shape and length cannot be achieved

Engineering Contradiction:
Improvetoe shape variabilityVSAvoidmachine structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent incorporates dynamically adjustable components including movable guide surfaces, adjustable positioning clamps, and variable-speed feed mechanisms that allow the toe-closer to adapt its configuration for different toe shapes and lengths. These dynamic elements enable the machine to handle various product specifications without requiring complete reconfiguration, balancing versatility with structural simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention designs the toe-closer machine with universal fixtures and adjustable mechanisms that can accommodate multiple toe configurations and product types. The same basic machine structure can produce different toe shapes and lengths by adjusting a few key parameters, eliminating the need for multiple specialized machines and reducing overall system complexity while enhancing adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If conventional sewing processes are used, then basic production is maintained, but production waste increases and productivity decreases

Engineering Contradiction:
Improvetights production efficiencyVSAvoidproduction waste
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent implements a continuous sewing process where the toe-closer machine operates without interruption, feeding fabric continuously through the sewing mechanism. This eliminates stopping and starting that causes material waste and reduces productivity, maintaining constant motion and seamless production flow that maximizes efficiency and minimizes waste generation.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The invention replaces manual positioning and alignment operations with automated mechanical guides and positioning systems that precisely locate and guide the fabric through the sewing process. This substitution eliminates misalignment and positioning errors that lead to defective products and waste, while maintaining high-speed continuous operation that boosts productivity.

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

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

Enables high-quality, uniformly produced tights with precise control over toe shape and dimensions, reducing waste and improving productivity through efficient and automatic sewing processes.

Implementation Method 1

Each presser (8) comprises a deformable foil (10)... the foil (10), being unable to translate, reacts by deforming in the centre and assuming an overall curved conformation

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2900856B1Apparatus and process for production of tights
Publication Date: 2016.11.09 SEGALA RENATO SRL
  • EP2900856B1 patent drawingFigure 1
  • EP2900856B1 patent drawingFigure 2
  • EP2900856B1 patent drawingFigure 3

AI summary

An apparatus (1) for production of tights, comprising a line-closer machine (2) suitable for joining a pair of tubular textile fabrics to one another, forming a semi-finished piece having a trunk part and two legs with open toes, and a toe- closer machine (3) suitable for sewing the toes of the legs of the semi-finished piece, where the toe-closer machine comprises a plurality of support tubes (4) for semi-finished workpieces, coupled two by two, in which each tube is provided with two blades (5) arranged at sides of the tube and longitudinally movable between a retracted position and an advanced position; the apparatus comprises a blocking and transport device (6) activatable on the toes of the semi-finished workpiece so as to block them in a predetermined configuration and transport them to a sewing machine for the toes to be closed by means of a sewing having a predetermined progression; the blocking and transport device comprises a plate (7) positioned inferiorly of the tubes and mobile between a lowered position and a raised position, in which it enters inferiorly into contact with the toes of the semi-finished workpiece wrapped-around the blades (5); the blocking and transport device (6) comprises at least a pair of pressers (8) solidly mobile between a raised position and a lowered position, in which they each lock a portion of toe of the semi-finished workpiece by pressing it on the underlying plane (7); each presser (8) assumes a straight configuration, in which it imposes a linear shape on the blocked portion of the respective toe, and a curved configuration, in which it imposes a curved shape on the blocked portion of the respective toe; the curved shape corresponds to the progression of the sewing.