Service Details

Casement ESPAG

The term Espagnolette (often abbreviated as Espag) refers to a sophisticated multi-point locking mechanism that has become the standard for modern casement windows and doors, particularly those constructed from uPVC and aluminium. Far exceeding the security and weather-sealing capabilities of traditional single-point latches, the Casement Espag system is essential for enhancing the performance and longevity of contemporary joinery.

Function and Operation

At its core, an Espag lock is a multi-point locking system activated by a single turn of a handle. Instead of a single bolt securing the sash (the opening part of the window or door) to the frame, the Espag system utilizes a long gear-driven rod that runs vertically along the sash's closing edge.

When the handle is turned, the internal gearbox mechanism drives the entire locking rod, simultaneously engaging multiple locking points along the length of the frame. This action secures the sash at the top, bottom, and various intermediate points, providing a robust, continuous seal and security barrier.

Key Components of a Casement Espag System

The system is a collection of interconnected hardware components working in harmony to deliver superior security and weather resistance.

• The Espagnolette Bar (The Gear Rod): This is the long metal strip that runs inside the sash profile, containing the locking points. Its length is crucial and is matched to the height of the door or window. It is the central piece that moves to engage and disengage the lock.
• The Gearbox: Located centrally on the Espag bar, this is the main operational unit. It connects directly to the handle spindle and translates the rotary motion of the handle into the linear (up and down or rotational) movement of the locking points. For casement systems, the classic function involves the rotation of the locking points into the keeps.
• Locking Points (Cams, Mushrooms, or Hooks): These are the individual locking elements attached to the Espag bar.
  • Mushroom Cams: The most common type, named for their shape, which interlocks with the keep on the frame, providing excellent resistance against forced entry and enhancing compression for superior weather sealing.
  • Roller Cams: Primarily used for compression and weather sealing, often alongside mushroom cams or hooks for security.
  • Shootbolts: Some high-security Casement Espag systems incorporate shootbolts at the top and bottom of the rod, which extend directly into the head and sill of the frame, offering maximum security.
• Keeps (or Strikers): These are the metal receiver plates fixed to the door or window frame. They are specifically designed to accept and securely latch the locking points (cams/mushrooms/hooks) when the handle is engaged. Their strategic placement ensures even pressure and security distribution along the sash.
• Handle and Spindle: The external component that the user operates. The spindle (a square metal bar) connects the handle to the gearbox, initiating the locking sequence. Handles are available in various styles and finishes to suit architectural aesthetics.
• Backset: A critical measurement, the backset is the distance from the centre of the spindle hole (the handle's axis) to the front faceplate of the Espag bar. This dimension must match the door or window profile to ensure correct fitment and operation.

Casement Espag system is not merely a lock; it is an integrated security and sealing solution. By unifying multiple locking points under a single, smooth operation, it provides modern casement doors and windows with the highest levels of security, weather protection, and functional longevity.