Gas Struts as Replacements for LIFT-O-MAT: Understanding N Ratings and Lengths
A gas strut (often used as a replacement for a LIFT-O-MAT) is a hydropneumatic adjustment fitting that opens furniture flaps in a controlled manner and holds them open. Selecting a suitable replacement part strictly depends on the exact extension force in Newtons (N) as well as the total extended length in mm.
What Exactly Is a Gas Strut as a LIFT-O-MAT Replacement?
A gas strut consists of a pressure tube and a piston rod. Inside, compressed nitrogen provides the necessary extension force. When the seals wear out after years of use, the gas escapes and the flap drops down. In this case, the component must be replaced. A direct replacement for a LIFT-O-MAT or comparable gas struts requires no modifications to the furniture carcass, provided that the technical parameters of the new part match the old one exactly.
Understanding Dimensions, Standards, and N Ratings
For the fitting to function correctly, two values are critical, which are usually printed directly on the housing:
- Extension force: Measured in Newtons (N). This value defines how much weight the strut can support. Typical values for kitchen wall units range between 50 N and 150 N. For solid fronts, versions with 200 N, 250 N, or more are used. The old part often displays a sequence of digits such as "0320N" – this corresponds to 320 N.
- Total length: The measurement from the centre of the front mounting eyelet to the centre of the rear eyelet when fully extended. Common lengths in furniture construction range from 245 mm - 270 mm.
- Stroke: The actual travel distance of the piston rod in mm as it retracts into the cylinder.
Types and Variants
The mechanism is identical in most models; the differences lie in force and appearance. Simple versions are sufficient for standard wall units, whilst large MDF or solid wood fronts require specialised gas struts for heavy flaps.
To blend in visually with the cabinet interior, these fittings are available in various finishes. A neutral silver gas strut is commonly chosen, as are black or white variants to match the carcass colour.
Application & Selection
The gas strut works like the damper on a car boot: it supports leverage during opening and locks the front securely at the highest point.
When choosing a replacement part, the Newton rating of the original part must not be altered arbitrarily. A strut that is too strong will jerk the flap upwards and strain the hinges, whilst a strut that is too weak will not support the weight. If carrying out a first-time installation, weigh the front panel including the handle. As a rough rule of thumb: 10 N of holding force corresponds to approximately 1 kg of weight force. When using two struts per flap, the weight is shared between them.
Besides traditional wall units, the principle of the gas strut is also utilised in other furniture fittings, such as a wardrobe lift inside a cabinet to gently raise the hanging rail back to its starting position after being pulled down.
Installation and Replacement
Replacing a defective strut is generally possible without tools or using a simple flat-blade screwdriver.
- Open and support the front flap.
- Gently pry up the small metal spring clip on the ball head of the old strut using the screwdriver.
- Pull the strut off the ball stud.
- Simply push the new strut onto the stud until the retaining clip audibly engages.
The pressure tube (the thick section) should point upwards when the cabinet is closed, ensuring that the internal seals remain permanently lubricated by the oil inside the cylinder.
Related Terms
- Flap stay: A mechanical fitting that holds flaps in position continuously, often designed as a friction stay without gas pressure. Further technical details can be found under flap stays.
- Flap fitting: The collective term for all hinge and support systems used on upward-opening furniture fronts. See flap fittings.
- Furniture damper: A small component (soft-close) that merely decelerates the closing of a door, but does not lift or hold fronts open.