Locks and Mechanisms

French Locks

French box locks manufactured during the eighteenth and nineteenth century are generally very simple mechanically speaking; many rely on, if not just one, only a few internal levers. The mechanism initially locks with one full anti-clockwise turn of the key but, unlike British locks, can then turn a further 360 degrees to essentially ‘double lock’ itself. The design of the internal lock bolt catered for this double throw action by having an elongated bolt arm. The reason for this double locking action is somewhat of an enigma as it doesn’t seem to enhance the overall security of the lock; one is left to speculate that it may serve to complicate and lengthen the work of the illegal lock picker.

An 1820's French lock in its 'double locked' position. Note the elongated bolt arm (top centre) to allow for the mechanism's double throw action.

An 1820’s French lock in its ‘double locked’ position. Note the elongated bolt arm (top centre) to allow for the mechanism’s double throw action.

The addition of a ‘curtain’ (a revolving metal keyhole sheath that prevents multiple lock picking tools gaining access to the levers) and unusually shaped drill pins help make these locks extremely hard to open without their characteristic keys, adding certain complication for any lock picker or locksmith with the unenviable task of key duplication. Drill pins in the shape of a heart, triangle, star, (playing card) spade, and cloverleaf have been known to be fitted to these French locks.

Made significant by its usage on the magnificent 1787 and 1791 French ’Nécessaire de Voyage’ boxes commissioned by Marie Antoinette, the cloverleaf shaped drill pin is believed to symbolise the Christian holy trinity.

1806 French double action lock with cloverleaf (tréfle) shaped drill pin and surrounding curtain from an Antique Jewellery Box in Cuban Mahogany, by Georges Monbro.

1806 French double action lock with cloverleaf (tréfle) shaped drill pin and surrounding curtain from an Antique Jewellery Box in Cuban Mahogany, by Georges Monbro.

French antique key with a cloverleaf (tréfle) shaped shaft.

French antique key with a cloverleaf (tréfle) shaped shaft.

French antique key with a cloverleaf (tréfle) shaped shaft.

French antique key with a cloverleaf (tréfle) shaped shaft.

French Antique Jewellery Box in Cuban Mahogany, by Georges Monbro.

French Antique Jewellery Box in Cuban Mahogany, by Georges Monbro.

1789 French lock with triangular shaped drill pin and surrounding curtain.

1789 French lock with triangular shaped drill pin and surrounding curtain. Note the small prongs to the edges of the key hole; this requires a ‘Z’ shaped key bit to pass through it.

French lock fittings are externally recognisable by their cylindrical links to the top link plate and circular entry points to the main lock housing. These attributes, though subtle, weren’t found on British boxes which instead had cuboid links to the top link plate and rectangular entry points to the main lock housing.

Circular entry point to a French lock housing.

Circular entry point to a French lock housing. The Cylindrical link from the link plate engages here.

Cylindrical link on the top link plate.

Cylindrical link on the top link plate.

French Antique Jewellery Box in Palisander Wood.

Circular entry points to the lock housing, and a cloverleaf (tréfle) shaped lock drill pin and key from a French Antique Jewellery Box in Palisander Wood.

It wasn’t uncommon for some French boxes to be fitted with English Bramah patent or Chubb locks, but their inclusion necessitated the customisation of the link plates and lock entry points accordingly.

Chubb Dectector Lock from a French Antique Nécessaire de Voyage Dressing Case in Ebony with Floral Brass Inlay by Aucoc Ainé à Paris.

Chubb Dectector lock from a French Antique Nécessaire de Voyage Dressing Case in Ebony with Floral Brass Inlay by Aucoc Ainé à Paris.

Antique Nécessaire de Voyage Dressing Case in Ebony with Floral Brass Inlay by Aucoc Ainé à Paris.

Antique Nécessaire de Voyage Dressing Case in Ebony with Floral Brass Inlay by Aucoc Ainé à Paris.

Turner Patent Lock

The Turner Patent lock, initially patented in 1798, can be disassembled into the following parts: READ MORE

Secret Compartments and Mechanisms

For centuries, secret compartments have been built into boxes and cabinets to hide their owner’s most valuable possessions, gold coins or private documentation. It wasn’t until the start of the 19th century that the inclusion of these secret, concealed compartments and mechanisms became more of an art form and a true symbol of a box maker’s ability and ingenuity. READ MORE

Chubb Detector Lock

After counterfeit keys were used to commit a burglary at Portsmouth Dockyard in 1817, the British government issued a competition to create a lock that could only be opened using its own key. In response, Jeremiah Chubb designed the Chubb Detector lock, the principle of which was first patented in 1818. READ MORE

Leuchars Patent Bramah Lock

The Leuchars Patent Bramah lock was inspired by the same thought processes that created the Asprey Patent Bramah lock; to have a lock that could counteract the forgetfulness of its owner by not only automatically locking itself, but also allowing the box to be opened even if the key has been misplaced. READ MORE

Bramah Locks

The complete Bramah lock can be disassembled into the following parts: READ MORE

George Davis Patent Lock

Based in Windsor, Berkshire, the lock maker, George Davis patented his ‘Double Chambered’ lock in 1799. READ MORE

Betjemann Patent Mechanisms

From 1859, based at 36, 38 & 40 Pentonville Road, London, George Betjemann and his two sons, George William Betjemann and John Betjemann, started to take the art of cabinet and box making to new creative heights. Under the business name of George Betjemann & Sons, they began to patent their innovative designs and mechanisms, and specific to boxes, there were two particularly impressive types of patented design. READ MORE

Spring-Loaded Mechanisms

The spring-loaded action is where an object or mechanism is held tightly against a spring, but is initially ‘locked’ into position. Once ‘unlocked’, the object or mechanism is propelled out by the natural action of the spring. READ MORE

Asprey Patent Bramah Lock

Asprey Patent locks were essentially Bramah locks that had been customised using Asprey’s own patented design. A normal box lock would simply be left in the unlocked position unless it was manually locked with a key. This meant that a forgetful, or over-trusting owner could easily leave the box unprotected and vulnerable. To try and combat this issue, some Bramah locks were modified by using a spring-loaded self-locking mechanism that automatically locks the box when the lid is closed.  READ MORE