Maltese Cross: Stop-Work to Vacheron Constantin Logo
In this article
SJX Watches has traced the Maltese cross from its mainspring stop-work origins to Vacheron Constantin’s 1880 logo adoption and Cleguer’s Horology Inspiration One. The outlet’s insight follows the component through barrel control, stepped indexing, Geneva stop-work terminology, heraldry, and modern watchmaking.
A Mainspring Limiter With Concave Arms
SJX Watches reports that the Maltese cross began as a stop-work. Its original purpose was to limit a mainspring’s working range. In this role, it prevented the winding barrel from being wound past a certain threshold and also prevented complete discharge. That allowed a movement to use the quasi-linear torque slope of the mainspring. The stop-work pairs a driving finger, identified as B, with a driven wheel, identified as A. The wheel has the shape of a true Maltese cross with concave arms. The finger is commonly fixed on the barrel arbour, while the wheel is commonly screwed onto the barrel cover. In a five-position Maltese cross stop-work, the permitted turns between limits are four. As a general rule, when the cross has n teeth, the barrel winds and unwinds n-1 times.
Stepped Motion and Self-Indexing
The mechanism’s transmission ratio is characterized as a true 1-to-any transmission ratio. Its driving component has one tooth. The cross-shaped wheel advances by one single step for every revolution of the driver. After the driver turns five times, the cross completes one full revolution. The motion type is stepped. The mechanism is self-indexing without using springs or jumpers. A figure of the mechanism comes from L. Defossez’s Théorie générale de l’horlogerie, Tome I. The Maltese cross also appears in perpetual calendars and unconventional jumping hours complications. As a horological component, it commonly has five arms or more.
Geneva Stop-Work and a Shift in Terminology
Today, the Maltese cross mechanism and Geneva stop-work are used interchangeably. Originally, however, they were different systems. The Maltese cross came after the Geneva stop-work. The original Geneva stop-work used a simple finger on the barrel arbour paired to a modified gear. Its wheel was a common gear with roughly half its teeth replaced by a circular sector.
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Heraldry, Vacheron Constantin, and Cleguer
The name comes from a heraldic symbol adopted by the Order of St. John. It is also associated with the Sovereign Military Order of Malta. Vacheron Constantin adopted the Maltese cross as a logo in 1880. The manufacture incorporates the symbol into its tourbillon cage and decorative screw heads. In Vacheron Constantin caliber 3200, the screw for the column wheel is fashioned with a Maltese cross head. Cleguer’s Horology Inspiration One features an inverted Maltese cross construction. Readers can test their watch knowledge with Watchdle at Watchdle.
FAQ
What was the Maltese cross doing before it became a logo?
It served as a stop-work to limit a mainspring’s working range. In that role it prevented over-winding and complete discharge while allowing use of the mainspring’s quasi-linear torque slope.
How does the stop-work advance its wheel?
The driving component has one tooth, and the cross-shaped wheel advances by one single step for each revolution of the driver. After five driver turns, the cross makes one full revolution, and the mechanism self-indexes without springs or jumpers.
How does the Maltese cross differ from the original Geneva stop-work?
The two systems were originally different, and the Maltese cross came after the Geneva stop-work. The original Geneva stop-work paired a simple finger on the barrel arbour with a modified gear whose teeth were roughly half replaced by a circular sector.
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