Lockable Gas Springs vs. Non-Locking Gas Springs: A Technical Comparison for Industrial Applications

In the world of industrial motion control, gas springs are essential components that provide controlled force, damping, and positioning for a vast range of applications. From ergonomic office furniture and medical equipment to automotive systems and industrial machinery, gas springs allow smooth lifting, lowering, and adjustment of loads. Within this category, the distinction between lockable and non-locking gas springs is critical. Understanding the technical differences, performance characteristics, and optimal application contexts for each type is essential for engineers, product designers, and procurement specialists. This article provides a comprehensive technical comparison of lockable and non-locking gas springs, supported by performance data and practical application guidance.

Understanding Gas Spring Technology

Gas springs are hydropneumatic adjustment elements that use compressed nitrogen gas contained within a sealed cylinder to exert a controlled force on a piston rod. Unlike mechanical coil springs, gas springs offer a nearly constant force over their stroke length, making them ideal for applications requiring smooth, controlled motion with minimal fluctuation in force. The basic design consists of a pressure tube, a piston with a sealing system, a piston rod, and a charge of nitrogen gas. The pressure differential across the piston generates an extension force that can be used to assist in lifting or counterbalance loads.

When the valve is open, gas flows between the chambers, allowing the piston rod to move freely. When the valve is closed, the gas is trapped, locking the piston in position. The key distinction between lockable and non-locking gas springs lies in the presence of a valve mechanism that can stop and hold the piston at any point in its travel.

Comparing Performance: Lockable vs. Non-Locking Gas Springs

To understand the performance differences between these two categories, it is essential to examine their mechanical behavior, locking characteristics, and suitability for different applications. The following table provides a detailed comparison of key performance attributes.

This comparison demonstrates that lockable gas springs offer significantly greater functionality than non-locking gas springs. The ability to lock in any position is the defining feature, enabling precise positioning and secure load holding in applications where stability is critical.

Quantified Advantages of Lockable Gas Springs

The operational advantages of lockable gas springs are supported by measurable performance data. Research and manufacturer specifications provide quantified evidence of their capabilities. For example, rigid locking gas springs can hold loads up to 10,000 N in the compression direction, providing exceptional load-bearing capacity for heavy medical and industrial equipment. The release force required to unlock a lockable gas spring is typically 25% of the extension force (F1), ensuring intuitive operation for users.

Lockable gas springs offer superior control and safety compared to non-locking alternatives. When locked, these springs maintain their position indefinitely without requiring additional power or external locking mechanisms. This feature eliminates the need for mechanical latches or electrical actuators, simplifying designs and reducing overall system complexity.

These quantified advantages translate directly into practical benefits for end users. The high holding force ensures that even heavy components remain securely in position when locked, enhancing safety in medical and industrial settings. The extended stroke range allows for greater adjustment flexibility in applications such as ergonomic workstations and patient care equipment. The low release force ensures comfortable and intuitive operation, improving user experience and reducing operator fatigue.

Understanding Locking Mechanisms and Types

Lockable gas springs are available in several configurations, each designed to meet specific application requirements. The fundamental distinction is between elastic locking and rigid locking. Elastic locking gas springs lock the piston in an atmosphere of nitrogen, providing a spring-loaded feel when the locked position is subjected to additional load. This type is ideal for applications such as office chairs where a comfortable, cushioned feel is desirable. Rigid locking gas springs use an oil chamber within the cylinder to achieve a solid lock with no movement under load. This provides a completely rigid holding force, making it suitable for applications such as surgical tables and medical beds where stability is paramount.

Within rigid locking, three main variants exist: rigid locking in compression, rigid locking in extension, and rigid locking in both directions. Rigid locking in compression is used in applications such as patient beds and massage tables, where downward loads must be supported. Rigid locking in extension is suitable for seat back adjustment and wheelchair recline systems. Rigid locking in both directions provides the highest level of control for applications requiring stability under any load condition.

Sealing Mechanism and Functionality

The core functionality of a lockable gas spring is based on a valve mechanism integrated into the piston. This valve is actuated by a release pin that extends through the center of the piston rod. When the release pin is depressed, the valve opens, allowing gas to flow between the chambers and enabling movement of the piston rod. When the release pin is released, the valve closes, trapping the gas and locking the piston in position. The release force required to actuate the pin is a critical design parameter, typically specified as a percentage of the extension force. The standard release travel for the pin is 2.5 mm, with options for 0.5 mm or 3.5 mm travel available to accommodate different release systems.

This simple yet effective mechanism provides reliable locking without requiring external power sources, making lockable gas springs cost-effective and environmentally friendly. The locking mechanism is fully contained within the cylinder, protecting it from contamination and wear. The system's self-contained nature also ensures consistent performance over extended service life, with minimal maintenance requirements.

Performance Visualization

To provide a visual representation of the performance differences between lockable and non-locking gas springs, the following charts present comparative data based on manufacturer specifications and industry standards.

These visualizations confirm the performance advantages of lockable gas springs over non-locking alternatives across multiple key dimensions.

Applications: Selecting the Right Gas Spring

Choosing between lockable and non-locking gas springs depends on the specific requirements of the application. Lockable gas springs are essential in applications where precise, variable positioning is required, such as ergonomic furniture, medical equipment, and industrial workstations. They allow users to adjust the position of a component and lock it securely in place, providing stability and safety. Non-locking gas springs are suitable for applications where constant force is needed but positional locking is not required, such as for lifting and counterbalancing hatches, lids, and doors.

For applications demanding the highest level of control, a lockable gas spring is the preferred choice. Our Lockable Gas Spring solutions offer the performance, reliability, and customization options needed for diverse applications across medical, industrial, and furniture sectors.

Quality and Reliability

Manufacturers of lockable gas springs typically offer products in a variety of configurations to suit different applications. Key parameters include force rating, stroke length, tube and rod diameter, locking type, and release mechanism. These parameters can be customized to meet specific application requirements, and products are available in steel or stainless steel construction for corrosion resistance and durability. Industry leaders such as Stabilus and SUSPA offer comprehensive product ranges, with Bansbach providing extensive customization options.

Quality assurance measures include gas leak testing, force testing, and endurance testing to ensure reliable performance over the product life cycle.

Conclusion

Lockable gas springs are superior to non-locking gas springs for applications requiring precise, variable positioning and secure load holding. Their ability to lock at any point in the stroke, combined with high force capacity and long stroke lengths, makes them versatile and reliable. The locking mechanism is simple, self-contained, and cost-effective, eliminating the need for external power sources. In contrast, non-locking gas springs are ideal for simpler applications. Understanding the performance differences and application requirements is essential for selecting the correct solution.

1. ISO 26909:2018 – Gas springs for automotive and industrial applications.
2. ASTM F1585 – Standard Specification for Gas Springs.
3. Stabilus Group – BLOC-O-LIFT Locking Gas Spring Technical Data.
4. SUSPA GmbH – Locking Gas Springs Product Catalog.
5. Bansbach easylift – Lockable Gas Spring Product Range.