Watch Winding Stem Axial Switching Mechanism
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Solution Overview
Problem
Existing watch movement mechanisms with two stems require a bulky gear transmission and movable frame, leading to inaccuracies and an inconvenient crown placement, as the outer crown is positioned closer to the back of the case rather than the median plane.
Innovation Solution
A winding and time-setting control device with a rotatable control rod and a sliding pinion rocker, integrated with a pull-bar mechanism, allowing axial displacement of the first stem to switch between winding and time-setting positions without a movable frame, using a compact and rigid pull-cord mechanism that maintains the crown in the traditional position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two stems are connected by a gear transmission and secured in translation, then the crown can be positioned in the median plane, but the device becomes bulky and the axial positioning becomes inaccurate
Solution Approach 1:
The patent extracts the gear transmission and movable frame from the system, replacing them with a pull-bar mechanism that directly connects the two stems. This removes the bulky intermediate components while maintaining the functional connection between the control stem and movement stem, thereby reducing device bulk while preserving crown positioning in the median plane.
Solution Approach 2:
The patent introduces a pull-bar mechanism as an intermediary between the control stem and movement stem. This pull-bar mechanism includes a pull-bar lever that translates the axial movement of the control stem into corresponding movement of the movement stem, eliminating the need for a bulky gear transmission and movable frame while maintaining accurate axial positioning.
2Power
If two stems are connected by a gear transmission and secured in translation, then rotation can be transmitted between stems, but the device requires a movable frame that increases size
Solution Approach 1:
The patent removes the movable frame containing the gear transmission and replaces it with a fixed pull-bar mechanism. The pull-bar lever directly transmits rotational motion from the control stem to the movement stem without requiring a bulky movable frame, thereby maintaining power transmission while reducing device size.
3Adaptability or versatility
If the crown is positioned closer to the back of the case, then the two-stem mechanism can be implemented, but the operation becomes inconvenient and unattractive
Solution Approach 1:
The pull-bar mechanism acts as an intermediary that enables the control stem to be positioned in the median plane (improving crown accessibility) while still effectively controlling the movement stem. This intermediary mechanism transmits both axial and rotational movements efficiently, making the crown convenient and attractive to operate while maintaining full mechanism functionality.
Data Source
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AI summary
The device (100) has a movement stem (2) rotating about an axis in a movement plate and secured to a sliding pinion (8) that is axially movable by a sliding pinion lever (52) in translation between a winding position in which the pinion cooperates with a winding mechanism (20) and a time-setting position in which the pinion cooperates with a time-setting mechanism (24). A control stem (1) rotating about a longitudinal axis is axially slidable between the winding and time-setting positions for cooperating with a manual control crown. A pull-out piece (60) drives the lever to move the pinion.