Locking Gas Springs: How Do They Function and When Are They Necessary?
How Do Locking Gas Springs Differ from Standard Struts?
Locking gas springs incorporate an internal release valve and piston separator that allows the user to lock the rod at any position in travel.
Standard gas springs rely on nitrogen pressure to assist lifting, but they are inherently dynamic—they push outward continuously. A locking gas spring provides a rigid or elastic stop at any point in the travel arc by manually actuating a release pin located at the end of the rod.
What is the mechanism behind a rigid locking gas spring?
Rigid locking springs use a secondary chamber of hydraulic oil separated by a floating piston to prevent compression or extension when locked.
When the release pin is not depressed, the hydraulic fluid is trapped on both sides of the piston. Because liquid is incompressible, the strut cannot move, creating a solid hold. This is essential for medical tables or heavy industrial guards where zero movement is tolerated under load.
How does an elastic locking gas spring function?
Elastic locking springs allow for slight movement under load because they trap gas instead of oil when the release valve is closed off.
These units offer a cushioned feel rather than a dead-stop. They are often used in ergonomic seating or automotive adjustment applications where a firm lock would be uncomfortable or could cause structural stress if impacted.
When should you specify a locking spring instead of a standard one?
Use locking springs when operator safety requires a secure position that stays fixed regardless of weight distribution or external force.
- Inspection hatches needing hands-free access at specific angles.
- Medical equipment requiring precise height or tilt adjustments.
- Heavy-duty machinery guards in industrial environments.
- Adjustable workbenches where the height must remain stable.
If you are unsure if your application requires a locking variant, you can use our gas spring force calculator to determine if a standard spring with high-friction damping would suffice, or if a positive lock is required for safety compliance.
How Do You Select the Right Locking Mechanism for Your Application?
Selection is based on the required load capacity, the frequency of actuation, and whether the application demands a rigid or elastic hold.
What are the common release systems for locking struts?
Release systems include mechanical cable-actuated buttons, direct-push levers, or remote-mounted handles for difficult-to-reach locations.
Most industrial setups use a cable-pull system, which allows you to mount the release trigger far from the spring itself. This is critical for machines with guarded interiors where reaching the actual strut end-fitting is dangerous or impossible.
Does the orientation of the gas spring affect the locking performance?
Locking springs must be installed with the rod end pointing downward to ensure the internal seal remains lubricated and the valve operates.
Improper orientation leads to valve failure and “sponginess” in rigid-locking models. Always consult the gas strut end fittings guide to ensure you have the correct bracket mounting to support the specific orientation required for your chosen model.
How do you calculate the force required for a locking application?
Calculation requires assessing the load at the pivot point and adding 20% to account for the internal friction of the locking valve system.
| Application Type | Required Lock Type | Safety Priority |
|---|---|---|
| Medical Bed | Rigid | High |
| Office Chair | Elastic | Low |
| Machine Guard | Rigid | High |
| Tooling Arm | Elastic | Medium |
What specifications should you check when choosing a locking gas spring?
Key specs include stroke length, force rating, mounting style, rod diameter, end‑fitting type, temperature range, and material finish.
Stroke length defines the travel distance the rod can move; choose a spring whose rated stroke exceeds your required movement to avoid bottoming out. Force rating (usually in Newtons or pounds‑force) must match the load at the pivot point plus a safety margin, typically 10‑20% higher than the calculated load.
Mounting style (eyelet, clevis, flange) and rod diameter affect how the spring attaches to your structure; ensure the end‑fitting matches your brackets and that the material (e.g., stainless steel for corrosive environments) suits the operating temperature and exposure conditions.
How Do I Diagnose a Locking Gas Spring That Has Failed?
Failure in locking springs usually manifests as drifting under load or a stuck release pin that will not engage or disengage correctly.
Why would a locking spring drift while in the locked position?
Drifting indicates an internal leak in the hydraulic section that allows fluid to bypass the piston seals under pressure.
This is a common failure point for units installed in abrasive industrial environments. If your industrial machinery guards are failing to hold, inspect the seals for debris, as this often leads to rapid internal seal degradation.
What should you do if the release pin is stuck?
A stuck pin is usually caused by cable tension issues or debris accumulation at the rod entry point, preventing full pin depression.
- Check for frayed or stretched release cables.
- Clean the area around the rod entry with compressed air.
- Verify the linkage has enough travel to fully actuate the valve.
Can locking gas springs be serviced or recharged?
Locking gas springs cannot be serviced or recharged because the valve and fluid chamber are permanently sealed during the manufacturing process.
When a locking unit fails, the entire assembly must be replaced. Attempting to force the valve or drill the cylinder is a significant safety hazard due to the high-pressure nitrogen charge contained within the body.
