Retractable Finger Mechanism for Fast Timepiece Display Jumps
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Solution Overview
Problem
Existing clockwork mechanisms for displaying time indications, such as days of the month or weeks, suffer from slow transition times due to the reliance on a 24-hour wheel rotation, and known solutions like dragging jumps or cam-activated levers consume additional energy.
Innovation Solution
A retractable finger device with an actuation module and drive module, featuring a finger cam and drive elements, allows the finger to rotate at a higher speed relative to the wheel, reducing jump time and energy consumption by alternating between deployed and retracted configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the finger is fixed to a 24-hour wheel that completes one revolution every 24 hours, then the mechanism is simple to implement, but the transition time between displays is slow
Solution Approach 1:
The finger is made dynamically retractable rather than fixed, allowing it to be deployed only when needed for actuation and retracted during non-actuation periods. This dynamic configuration change enables the finger to achieve higher effective speeds during display transitions while maintaining mechanical simplicity through controlled motion cycles
Solution Approach 2:
The finger operates in periodic cycles of deployment and retraction, being deployed to engage the star wheel for instantaneous display jumps and then retracted for the remainder of the 24-hour cycle. This periodic action pattern allows the mechanism to achieve fast transition speeds during brief actuation moments while maintaining overall system simplicity
2Loss of time
If dragging jump mechanisms are used to reduce transition time, then the jump time is partially reduced, but additional energy is consumed
Solution Approach 1:
The mechanism uses instantaneous jumping action where the deployed finger rapidly engages the star wheel teeth to complete the display transition in minimal time. This skipping approach rushes through the actuation event quickly rather than using gradual dragging motions, thereby reducing both time loss and energy consumption during the jump
Solution Approach 2:
The finger is extracted or removed from continuous contact with the star wheel, engaging only during brief instantaneous jumps rather than maintaining continuous dragging contact. This extraction of the finger from constant engagement eliminates unnecessary energy consumption while achieving fast transition times during actuation moments
3Speed
If cam-activated levers are used for instantaneous jumps, then the jump is instantaneous, but additional energy is consumed to perform the jump
Solution Approach 1:
The retractable finger mechanism serves itself by using the natural rotation of the 24-hour wheel to automatically deploy and retract the finger at the appropriate moments. This self-service operation eliminates the need for additional energy-consuming cam-activated levers while maintaining instantaneous jump capability through the finger's automated deployment cycle
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 device significantly reduces the time required for display transitions and minimizes energy use compared to conventional mechanisms, enabling faster and more efficient time indication changes.
Implementation Method 1
the return element is in the form of a spring blade 26 which extends along a curved path around the finger cam 28
Data Source
Figure 1~3
Figure 4~5
Figure 6a~6c
AI summary
The present invention relates to a retractable finger device (10) for a watch movement, comprising an actuation module (20) for a watch mechanism, in particular a multi-time display mechanism, and a drive module (40) arranged to drive the actuation module (20) so that it can perform a succession of 360° rotation cycles. The actuation module (20) comprises a finger (22), a finger support (30) on which the finger (22) is mounted, a finger cam (28) arranged to cooperate with the finger (22), a first drive member (32) integral with the finger support (30) and a second drive member (34) integral with the finger cam (22).The drive module (40) comprises a first transmission member (50) arranged to drive the first drive member (32) and a second transmission member (62, 66a, 66b) arranged to drive the second drive member (34) so as to induce a relative movement between the finger support (30) and the finger cam (28). This relative movement allows the finger (22) to move from a deployed to a retracted configuration and vice versa. The finger (22) is arranged to actuate the watch mechanism when the finger passes through the deployed configuration. The finger (22) is also arranged to disengage from the watch mechanism when the finger passes through the retracted configuration so as not to actuate said mechanism with each rotation cycle of the drive module (20).