Horological Device Stud with Spherical Head for Hairspring Positioning

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Solution Overview

Problem

Existing watchmaking devices face challenges in attaching balance springs to cocks, leading to stress and inaccuracy due to defects in the connection between the eyebolt and hairspring, particularly when the hairspring is made of fragile materials like silicon, where manual correction is difficult or impossible.

Innovation Solution

A watchmaking device featuring a pin with a body and head, where the pin's body is partly in a slot on the support and the head has a spherical surface, allowing the eyebolt to move and pivot freely before being locked into a specific position and orientation, minimizing stress on the hairspring and accommodating its natural position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the stud is rigidly fixed to the support, then the attachment is secure, but stress is transmitted to the hairspring causing deformation and loss of concentricity

Engineering Contradiction:
Improveattachment securityVSAvoidconcentricity of hairspring
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The stud is designed with a spherical head that can pivot and translate within a slot, transforming the rigid fixed connection into a dynamic adjustable connection. This allows the stud to adapt its position and orientation to accommodate variations in the eyebolt-hairspring connection without transmitting stress that would deform the hairspring, while still maintaining secure attachment when locked.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The slot acts as an intermediary element between the spherical head of the stud and the support. It provides a constrained path for movement, allowing the stud to adjust its position while limiting the range of motion. This intermediary structure enables both flexibility for stress relief and control for maintaining proper positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the stud is allowed to move freely, then stress on the hairspring is minimized, but the positioning precision is insufficient

Engineering Contradiction:
Improvepositioning accuracy of hairspring endVSAvoidstress on hairspring
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The stud transitions from a completely fixed state to a dynamically adjustable state within the slot. The spherical head can pivot and translate along the slot's path, providing controlled freedom of movement. This dynamic capability allows the system to find the optimal stress-free position while the slot constraints ensure the positioning remains within acceptable precision limits.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the positional parameters of the stud by allowing it to move along the slot rather than maintaining a fixed coordinate. The slot defines a permissible range of motion in specific directions while constraining movement in other directions, effectively changing the degrees of freedom available to the stud.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a complex multi-part stud structure is used, then freedom of orientation is improved, but device complexity increases

Engineering Contradiction:
Improvefreedom of orientation of hairspringVSAvoidstructure of stud
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention merges multiple functions into a single integrated stud component. The stud body incorporates both the spherical head for pivoting and the slot-receiving portion for translation in one piece, eliminating the need for separate ball joints and mounting brackets. This consolidation achieves the desired freedom of orientation while reducing overall structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stud is designed as a multi-functional element that simultaneously provides: (1) a spherical head for pivoting motion, (2) a body that fits into the slot for translational adjustment, and (3) a locking mechanism interface. This universal design allows a single component to handle multiple adjustment requirements without needing additional specialized parts.

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

4Manufacturing precision

If manual correction of the terminal curve is performed, then flatness of the hairspring can be restored, but the operation is delicate and impossible for silicon materials

Engineering Contradiction:
Improveflatness of hairspringVSAvoiddifficulty of correction operation
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention performs the positioning action preliminarily, during the assembly process itself. By allowing the stud to adjust its position and orientation within the slot before final locking, the system pre-establishes the correct stress-free configuration. This eliminates the need for subsequent delicate manual correction operations, particularly for fragile silicon hairsprings that cannot withstand such manipulation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The stud-hairspring assembly performs its own positioning function through the mechanical freedom provided by the spherical head and slot combination. The system self-adjusts to the correct configuration without requiring external manual intervention for correction. The stud essentially services its own positioning needs by pivoting and translating to accommodate the actual position of the eyebolt-hairspring connection.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4492156A1Horological device
Publication Date: 2025.01.15 RICHEMONT INTERNATIONAL SA
  • EP4492156A1 patent drawingFigure 1~2
  • EP4492156A1 patent drawingFigure 3~4
  • EP4492156A1 patent drawingFigure 5~6

AI summary

The invention relates to a watchmaking device (1) comprising a balance spring (4), a locking element (6), a stud (5) and a fixed or movable support (31) comprising a slot (11) extending parallel to the plane of the spring (4) and opening onto two opposite faces of the support (31) in the direction of the axis (A) of the spring (4), said stud (5) comprising a body (51, 52) arranged partly in the slot (11) and fixing the outer end (41) of the spring (4) on the side of the support (31) facing the spring (4) and a head (53) comprising a spherical surface arranged on the other side of the support (31) and axially retaining the stud (5) in the slot (11).When the locking element (6) is not in the locked position, the pin (5) can move in the longitudinal direction of the slot (11) and can pivot relative to the support (31) in three degrees of freedom to take a given position and orientation and when the locking element (6) is in the locked position, it presses the head (53) against the support (31) to lock the pin (5) in the said given position and orientation, the contact of the locking element (6) and the support (31) with the head (53) being made at the level of the spherical surface.