Wristwatch Clasp Inversion for Easy Donning and Maintenance Access

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Solution Overview

Problem

Conventional wristwatches with integrated folding clasps are uncomfortable to put on or take off, especially for people with reduced hand mobility, and they pose difficulties in presentation and access to the watch's back for maintenance due to the clasp's placement under the watch case.

Innovation Solution

A wristwatch design featuring a clasp that can be completely opened by unhooking from the watch case, with a single-strand bracelet and a pivoting locking member that allows for easy manipulation and secure closure, enabling the watch to be put on or taken off without direct contact with the inner wrist face and providing enhanced accessibility for maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a folding clasp is integrated under the watch case, then the bracelet can be closed securely, but the watch becomes difficult to put on or take off especially for people with reduced hand mobility

Engineering Contradiction:
Improvesecure closureVSAvoidease of donning and doffing
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The clasp is inverted from the conventional under-case position to a position above the watch case. The frame of the clasp is arranged to close over the watch case from above, with the locking member positioned on the upper face of the case. This inversion allows the bracelet to be opened completely by unhooking the frame from the case, making it easy to put on or take off the watch without requiring manipulation of small components near the back.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If a folding clasp is integrated under the watch case, then the bracelet can be closed securely, but access to the back for maintenance becomes difficult

Engineering Contradiction:
Improvesecure closureVSAvoidaccess to back
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The clasp and its locking mechanism are inverted to position above the watch case rather than under it. The frame closes over the case from above, and the locking member is positioned on the upper face. This inversion provides clear access to the back of the watch case for maintenance operations such as opening the back to access the movement or replacing the battery, eliminating the obstruction caused by under-case clasps.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If manipulation members are positioned near the back of the watch, then the clasp can be secured, but the members become difficult to handle

Engineering Contradiction:
Improvesecure closureVSAvoidease of manipulation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The manipulation members (lugs or push buttons) are repositioned from a lateral position near the back to a vertical position above the dial plane. The locking member extends above the crystal to a height that allows easy grasping and manipulation. This dimensional change places the manipulation interface in a more accessible location that is easier to reach and operate.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If the clasp is integrated to the watch case, then the bracelet can be closed securely, but the watch cannot be presented flat in a window

Engineering Contradiction:
Improvesecure closureVSAvoidpresentation capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The clasp is designed as a separable assembly consisting of a frame and a locking member rather than being permanently integrated into the case. The frame can be unhooked from the case by manipulating the locking member, allowing the bracelet to be completely opened. This segmentation enables the watch to be presented flat in a window or on a display surface while maintaining secure closure when worn.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3172981B1Wristwatch comprising a clasp bonded to the case
Publication Date: 2018.04.25 G&F CHATELAIN SA
  • EP3172981B1 patent drawingFigure 1~2
  • EP3172981B1 patent drawingFigure 3~4
  • EP3172981B1 patent drawingFigure 5

AI summary

Wristwatch comprising: a watch case; a strap; a strap clasp comprising a single strand, one end of which is attached to said watch case and the other end is attached to the clasp; the clasp being arranged to fasten over the watch case when the strap is closed.