Date Wheel Calendar Drive for Multi-Step Instantaneous Jumps

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Solution Overview

Problem

Existing clockwork calendar systems face challenges in energy efficiency, compactness, and torque fluctuations, particularly in implementing instantaneous jump drives for annual, semi-perpetual, or perpetual calendars, due to energy consumption by return springs and bulky month programming cams, which lead to premature wear and torque variations.

Innovation Solution

A clockwork calendar system with a drive device comprising a finger and tooth configuration that allows for instantaneous date changes, utilizing a desmodromic system and a spring-loaded rocker to minimize energy loss and optimize the drive mechanism, enabling compact integration and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a return spring is used to actuate the drive finger against the month programming cam, then the calendar system can operate, but energy is consumed and torque fluctuations occur

Engineering Contradiction:
Improvecalendar system operationVSAvoidenergy consumption by return spring
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The invention extracts and removes the return spring from the drive mechanism. Instead of using a spring to return the drive finger to its initial position, the system uses a cam profile that passively guides the finger through its motion path, eliminating the energy-consuming spring while maintaining operational functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces a cam profile as an intermediary element between the drive finger and the month programming cam. This cam mediates the motion by providing a controlled path that eliminates the need for active spring actuation, reducing energy consumption while ensuring proper timing and positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a bulky month programming cam is used, then the calendar system can be implemented, but the drive mechanism occupies excessive space

Engineering Contradiction:
Improvecalendar system functionalityVSAvoidspace occupied by drive mechanism
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The invention merges the month programming cam with the date wheel assembly, integrating multiple functions into a single compact structure. This consolidation eliminates the need for a separate bulky cam while maintaining all necessary calendar operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention implements a nested arrangement where the month programming cam is positioned concentrically with the date wheel, and the drive finger mechanism is nested within the available radial space. This nesting approach maximizes space utilization and minimizes the overall volume of the drive mechanism.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Duration of action of moving object

If the drive finger is elastically returned against the cam by a return spring, then the mechanism can reset, but premature wear occurs

Engineering Contradiction:
Improvereset capabilityVSAvoidmechanism wear resistance
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The invention converts the potentially harmful elastic return spring action into a beneficial cam-guided motion. The cam profile is designed to naturally guide the drive finger through its motion path and return it to the initial position without elastic forces, eliminating premature wear while maintaining the reset capability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The cam profile is designed to automatically guide the drive finger through its complete motion cycle and return it to the starting position without requiring external spring actuation. The system serves itself by using the cam's geometric profile to control the entire sequence of movements.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4187327B1Timepiece calendar system
Publication Date: 2026.02.11 ROLEX SA
  • EP4187327B1 patent drawingFigure 1
  • EP4187327B1 patent drawingFigure 2
  • EP4187327B1 patent drawingFigure 3

AI summary

Clock calendar system (200), the system comprising: - a date wheel (4) movable step by step relative to a frame (199); - a first finger (21) for driving the date wheel (4); - a first tooth (51) for driving the date wheel (4), the first tooth (51) being mounted movable on the date wheel (4) between a deactivated or retracted position and an activated or driving position; - an activation system (6, 7) for the first tooth (51); the first driving finger (21) and the first tooth (51) being arranged so that a single action of the first driving finger (21) on the first tooth (51) can cause a displacement of the date wheel (4) by N steps, N being an integer such that N>1, in particular N=2 or N=3.