Layered Watch Strap Structure for Bendability and Wear Comfort
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Solution Overview
Problem
Existing wristwatch straps made of synthetic resin or leather suffer from reduced bendability and wear comfort as thickness increases, leading to potential deterioration due to repeated bending.
Innovation Solution
A strap design featuring a stacked structure with multiple layers, including a flexible plastic core and nonwoven cloth layers, which enhances bendability and prevents deterioration by using temperature-dependent plastic sheets and nonwoven cloth to maintain flexibility and adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the strap is increased to meet design requirements, then the strength and durability are improved, but the bendability degrades and wear comfort deteriorates
Solution Approach 1:
The strap is divided into multiple functional layers: a flexible plastic core layer providing bendability, fabric layers providing strength and durability, and adhesive layers bonding them together. This segmentation allows each layer to contribute its specific properties, resolving the contradiction between thickness-related strength and bendability.
Solution Approach 2:
The strap uses a composite structure combining different materials: flexible plastic (for bendability), fabric (for strength), and adhesive materials (for bonding). This composite approach enables the strap to simultaneously achieve both high strength from increased thickness and high bendability from the flexible plastic layer.
2Shape
If the thickness of the strap is increased, then the design requirements are met, but the strap becomes prone to deterioration due to repeated bending
Solution Approach 1:
By segmenting the strap into a flexible plastic core layer and fabric outer layers, the structure accommodates repeated bending at the flexible plastic layer while the fabric layers maintain structural integrity and resist deterioration, allowing increased thickness without compromising reliability.
Solution Approach 2:
The flexible plastic core layer changes its physical parameters (becomes more flexible) to accommodate repeated bending, while the fabric layers maintain their structural parameters to resist deterioration. This parameter differentiation resolves the contradiction between thickness and resistance to deterioration.
3Ease of manufacture
If a single-layer structure is used, then the manufacturing is simpler, but the bendability and wear comfort are insufficient
Solution Approach 1:
The strap is segmented into specialized layers: flexible plastic core for bendability, fabric layers for comfort and strength, and adhesive layers for bonding. This segmentation improves wear comfort while maintaining reasonable manufacturing simplicity through standardized layering and bonding processes.
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 maintains high bendability and wear comfort even with increased thickness, preventing deformation and deterioration, while allowing for customizable thickness distribution and improved usability.
Implementation Method 1
at least a core main body 15 having moderate flexibility, and at least one auxiliary core 16, 17... formed of a flexible plastic sheet 221 having flexibility and temperature dependency
Implementation Method 2
a adhesive material 231 different in material from the flexible plastic sheet 221... the adhesive material 231 and the flexible plastic sheet 221 are bonded to each other
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A strap (1) is provided with a core (3) having a core main body (15) having a plurality of members including at least a member (21) having flexibility is stacked, and a skin member (2) surrounding the core. The core main body (15) is formed of a variable performance member and a special member bonded to each other with thermocompression bonding to be stacked in a face-back direction of a timepiece. The variable performance member has flexibility and temperature dependency, and is formed including plastic.