Lockable Gas Spring | 10×509mm | Stroke 200mm | 1050N | AXS-GSL-10101

Locking Gas Springs for Stepless Positioning

Locking gas springs combine the supporting force of a conventional gas spring with the ability to lock continuously at any position within the stroke. They can assist with lifting, lowering or adjusting a movable component and then hold it at the required position.

An internal valve is operated by a release pin. While the release pin is pressed, the piston rod can move in or out. When the release mechanism is released, the valve closes and the gas spring locks in its current position.

Locking gas springs are suitable for adjustable seats, backrests, treatment tables, desks, machine covers, control panels and medical equipment. A suitable release system — such as a direct lever or Bowden cable — is also required.

How the Locking Function Works

When the valve is open, gas or the internal operating medium can flow between the working chambers. The piston rod can then move while the gas spring partially balances the weight of the application.

When the release pin is no longer operated, the valve closes. The internal flow is interrupted and the piston rod remains at the selected position.

The release system must be designed so that:

• the release pin is operated through a sufficient distance
• the valve can close completely after release
• no permanent residual actuation remains
• the lever or Bowden cable operates without jamming
• the operating force is suitable for the user

An incorrectly adjusted release system may prevent the gas spring from moving freely or from locking reliably.

How to Select the Right Locking Gas Spring

Proceed in the following order:

1. Determine the installation lengths — measure the distance between the mounting points in both end positions.
2. Define the required stroke — the adjustment range must remain within the maximum stroke St.
3. Determine the extension force — consider the weight, centre of gravity, lever arm, mounting position and number of gas springs.
4. Determine the locking force — establish the maximum load that may act while the gas spring is locked.
5. Select the locking type — decide whether slight elastic movement is acceptable or whether the position must be as rigid as possible.
6. Check the load direction — determine whether the highest load acts in extension or compression.
7. Select the release system — consider the operating travel, release force, available space and Bowden cable length.
8. Select the end fittings — choose ball joints, eye ends or clevis ends according to the movement and connection thread.
9. Check the operating environment — consider temperature, humidity, dust, cleaning agents and surrounding media.

The required extension force cannot be determined from the weight of the movable component alone. The centre-of-gravity position, mounting points and installation angle have a major influence on the effective torque.

Difference from Standard Gas Springs and Locking Tubes

A standard gas spring supports movement but cannot hold the application at any chosen position within the stroke.

A locking tube mechanically secures a gas spring only in the fully extended end position. It cannot hold intermediate positions.

A locking gas spring can be moved within its adjustment range after the release mechanism is operated and then locked at the required position. It is therefore the appropriate choice where stepless adjustment is required.

If only the fully open position needs to be secured mechanically, a locking tube may be the more suitable solution.

Installation & Safety

Locking gas springs are under high internal pressure and must not be opened, drilled, heated, welded or mechanically modified.

For reliable operation:

• apply the load only in the axial direction
• avoid lateral forces, distortion and misalignment
• use sufficiently articulated end fittings
• protect the piston rod against scratches, paint and dirt
• provide separate mechanical end stops
• do not exceed the maximum stroke
• check the release system throughout the complete stroke after installation
• select the installation position according to the locking type

Before commissioning, verify that the gas spring locks securely at every intended position and releases fully when operated. Locking gas springs must not be used as the sole safety device without further assessment. If unintended lowering or closing could endanger people, additional mechanical safety measures are required.

Typical Applications

Locking gas springs are commonly used in:

• seat and backrest adjustment systems
• medical treatment tables and therapy equipment
• height- and angle-adjustable desks
• machine covers and control panels
• ergonomic workstations
• rehabilitation and care products
• furniture and adjustable beds
• special-purpose and commercial vehicles

The gas spring, release system, end fittings, brackets and mounting points must all be matched to the application.