Timepiece Crown Rotation Mechanism Locked State

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Solution Overview

Problem

Existing timepieces with locked crowns require users to unlock and rotate the crown for winding, which is cumbersome, and previous solutions increase the number of components, imposing design constraints.

Innovation Solution

A timepiece design that allows the crown to be rotated while locked, using an engagement member and engagement part structure that restricts axial movement but enables rotational movement, eliminating the need for additional components outside the crown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the crown is locked with a screw structure to prevent unintended operations, then security against unintended operations is improved, but ease of operation deteriorates because the user must unlock and rotate the crown every time the mainspring is wound

Engineering Contradiction:
Improvesecurity against unintended operationsVSAvoidease of winding operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The crown is divided into two functional parts: a head portion for user operation and an operation portion that extends into the case. The head can be rotated independently to wind the mainspring through the operation portion, while the operation portion remains engaged with the movement. This segmentation allows winding without full unlocking, improving ease of operation while maintaining security.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The operation portion acts as an intermediary between the head and the movement. It transmits rotational motion from the head to the movement's winding mechanism while being restrained by the guard part. This intermediary structure enables partial operation (winding) without complete unlocking, resolving the contradiction between security and ease of operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If an operation part is provided separately from the crown head to enable rotation when locked, then ease of operation is improved, but device complexity increases due to additional components

Engineering Contradiction:
Improveease of winding operationVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The operation portion is merged with the crown as an integrated structure rather than a separate component. It extends from the crown head and is directly connected to the movement, eliminating the need for additional intermediate parts. This merging reduces device complexity while enabling rotation during locked state for winding operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The operation portion serves multiple functions: it transmits rotational motion for winding, maintains engagement with the movement, and allows the crown to be held in a locked position while still permitting winding operations. This multi-functionality eliminates the need for separate unlocking mechanisms, reducing overall device complexity.

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

Data Source

PatentEP3974915B1timepiece
Publication Date: 2024.11.27 CITIZEN WATCH CO LTD
  • EP3974915B1 patent drawingFigure 1
  • EP3974915B1 patent drawingFigure 2
  • EP3974915B1 patent drawingFigure 3A~3B

AI summary

A timepiece according to an embodiment enables a crown to be rotated even when it is locked, using a structure that does not cause constraints of design. The timepiece includes an outer case having a movement therein, the outer case having a crown hole through a portion thereof, an engagement member connected to the outer case, and a crown. The crown includes a shaft part inserted into the crown hole and connected to the movement, an operation part holding the shaft part movably along an axial direction of the shaft part and enabling the shaft part to rotate in a circumferential direction, and an engagement part disposed between the engagement member and the operation part and restricting movement of the operation part in the axial direction when engaged with the engagement member, the engagement part rotatably holding the operation part whether or not engaged with the engagement member.