Aventos Flap Fittings: Function & Matching Gas Struts (Replacement for Blum)

An Aventos type flap fitting (Blum) is a mechanical lifting system for wall cabinets that swings, folds, or lifts fronts upwards. As a functional alternative or to replace defective lever mechanisms, standardised gas struts are frequently used, with their lifting force precisely calculated in Newtons to hold the weight of the flap securely in any position.

What exactly are flap fittings?

In modern furniture construction, flap fittings replace traditional hinged doors on wall cabinets. They allow unimpeded access to the interior of the cabinet without open doors protruding into the room. Well-known systems such as Aventos work with complex spring energy storage mechanisms. When these wear out or a cost-effective alternative for custom builds is required, fitters and joiners turn to pneumatic cylinders.

These cylinders operate like the tailgate struts of a vehicle, neutralising the front's own weight during opening and minimising the effort required. Important for technical planning: a gas strut is an active lifting element and must not be confused with a pure furniture damper (for soft-close), which merely slows down the closing motion.

Operating principle and replacement with gas struts

A gas strut consists of a pressure tube filled with nitrogen and a piston rod. When the flap is closed, the gas is compressed; when opened, it expands and pushes the piston rod out. This stroke supports the upward movement of the furniture front.

If defective fittings need replacing or simple flap stays are to be upgraded, installation is usually carried out via ball joints on special mounting plates. These are attached to the cabinet carcase (side panel) and to the inside of the front. The opening angle is determined by the position of the mounting points and is generally between 75° and 110°.

Dimensions, standards, and the right force in Newtons (N)

Precise dimensioning is crucial for functionality. If the strut is too weak, the flap will fall shut. If it is too strong, the cabinet can only be closed with great effort. Force is specified in Newtons (N).

• Length: Typical dimensions for furniture making are between 250 mm - 280 mm (in the extended state).
• Force calculation: As a rule of thumb: 10 N corresponds to a lifting force of roughly 1 kg.
• Example: If an MDF front weighs 4 kg including the handle, a strut of at least 200 N is required per side (with double-sided installation).

For large fronts made of solid wood or with glass inserts, gas struts for heavy flaps must be used. In these cases, models with 350 N or 400 N are frequently fitted.

Use & selection for kitchen cabinets

The primary area of application for these fittings is kitchen wall cabinets, for example above the sink, where a dish drainer rack for wall cabinets is often concealed. The upward-opening front prevents head injuries while working in the kitchen.

Whilst lever mechanisms are favoured in the upper area of the room, ergonomics in base cabinets demand entirely different fitting types. Here, drawer systems are used. To achieve consistent lines throughout the kitchen, the widths of wall cabinets are often aligned with base units, so that a 60 cm wide flap sits precisely above a kitchen cabinet 60 cm pull-out.

Related terms

• Concealed hinge: Cup hinge that is often used in combination with simple gas struts (as a pivot point at the top of the cabinet carcase).
• Stroke: The maximum extension distance of the piston rod in mm.
• Carcase: The fixed structural body of the piece of furniture (excluding fronts).