Full-Rotation Hook Air-Layer Structure for Wear-Free Sewing
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Solution Overview
Problem
Conventional full rotation hooks suffer from high replacement frequency and low durability due to wear caused by friction between the track projection and track groove during high-speed rotation, necessitating frequent lubrication that can contaminate threads and materials.
Innovation Solution
A full rotation hook design featuring a track projection with a notch part that allows compressed air to be supplied between the track projection and track groove, reducing friction through an air layer, and a configuration that prevents co-rotation of the inner holder, eliminating the need for lubrication oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the track projection is made of conventional materials (high-density polyethylene, liquid crystal polymer, or heat resistant synthetic resin), then seizure between the track projection and track groove is prevented during high-speed rotation, but the track projection suffers from wear due to friction, resulting in high replacement frequency and low durability
Solution Approach 1:
Compressed air is introduced as an intermediary substance between the track projection and track groove to reduce direct frictional contact. The air layer acts as a mediator that maintains separation between the rotating outer shuttle and the stationary inner holder, preventing both seizure and wear while allowing high-speed operation.
Solution Approach 2:
The invention utilizes pneumatic pressure by supplying compressed air through vent holes to create a pressurized air layer between the track surfaces. This pneumatic approach replaces conventional lubrication methods and material-dependent friction reduction with a gas-based separation mechanism that enhances durability.
2Force
If lubricating materials are added to the track projection to reduce friction, then rotational torque of the outer shuttle is reduced, but the lubricating material can contaminate threads and materials during sewing
Solution Approach 1:
The invention replaces the mechanical lubrication system (solid lubricating materials embedded in the track projection) with a pneumatic system (compressed air). This substitution eliminates the source of contamination while maintaining the friction-reduction function, allowing the outer shuttle to rotate smoothly without leaving residue on threads or materials.
Solution Approach 2:
Compressed air creates an inert gaseous environment between the track surfaces, replacing the need for solid lubricants. This inert atmosphere prevents contamination of sewing materials while still reducing friction, as air molecules do not adhere to or stain threads and fabrics like liquid or solid lubricants would.
3Stability of the object's composition
If the track projection and track groove are made to fit tightly to reduce play, then rotational stability is improved, but frictional heat increases causing seizure at high speeds
Solution Approach 1:
The invention addresses the heat problem by introducing a third dimension - the air gap created by compressed air pressure. Instead of merely adjusting the fit between surfaces, the pressurized air layer adds a dimensional separation that reduces thermal contact while maintaining positional stability through the pneumatic cushion.
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 design reduces friction and prevents seizure between the track projection and track groove, ensuring high-quality stitches without thread contamination, enhancing sewing efficiency and durability.
Implementation Method 1
the track projection and the track groove are separated with a compressed air layer
Implementation Method 2
reduces friction through an air layer
Data Source
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AI summary
Provided is a full rotation hook (1) with high durability. The full rotation hook (1) includes: an inner holder (5) having a track projection (30) that extends in a circumferential direction along an outer circumference; and an outer shuttle (4, 4A, 4B) having a track groove (25) to fit into the track projection (30) and a hook point (8) that catches an upper thread supplied by a sewing needle (2). In this full rotation hook (1), the outer shuttle (4, 4A, 4B) is rotationally driven about a rotation axial line (L2) with the inner holder (5) being prevented from rotating; the outer shuttle (4, 4A, 4B) includes a bottom part (31) having an inlet (44) for being supplied with compressed air, and a circumferential wall part (43) having a plurality of outlets (45a, 45b) that open to a space (16) of the track groove (25); the bottom part (31) and the circumferential wall part (43) have vent holes (24) that provide communication between the inlet (44) and the outlets (45a, 45b); and the track projection (30) has a notch part (54) that opens radially outward.