A gas spring is an industrial accessory that supports, cushions, brakes, adjusts height and angle. The principle is to fill the closed pressure cylinder with inert gas or oil and gas mixture, so that the pressure in the cavity is several or dozens of times higher than the atmospheric pressure, and the movement of the piston rod is caused by the cross-sectional area of the piston rod being smaller than that of the piston. pressure difference to achieve. Due to the fundamental difference in principle, self-locking gas springs have obvious advantages over ordinary springs, such as relatively slow speed, small power changes (generally within 1:1.2), and easy control.
A self-locking gas spring is an energy storage device similar to a mechanical spring. The mechanical spring stores energy by stretching the materials that make up the spring. Energy is stored by compressing nitrogen gas in a gas spring. When the mechanical spring is compressed, additional strain is placed in the spring, which increases the stored energy of the spring. Also, when compressed, the volume of the air chamber decreases as the shaft enters the gas spring tube; thereby increasing the gas pressure and storing more energy.
The function of the self-locking gas spring is to move or prevent the movement of certain objects. Typically, for self-locking gas springs, the object to be moved is applied to the hood and the support panel is applied to the hospital bed, of course, it is not limited to these uses, but can actually be used in many applications where ordinary springs are used.
One difference between mechanical springs and self-locking gas springs is the force provided on their free length. Self-locking gas springs always require some initial force to start compressing, whereas mechanical springs have a property called free length. This is the unforced length. The force required to move the spring starts at zero and increases according to stiffness. The "free length" of a self-locking gas spring requires some initial force before any movement can occur. After the initial force is fully applied, compression will begin. The force can be between 20N and 450N. In mechanical springs, the initial force is called preload and requires additional hardware to achieve.
One notable difference is speed. Small packages can be used to design self-locking gas springs with very low stiffness. A similar mechanical spring would require twice the packaging space.
Another major difference is that self-locking gas springs have a controlled rate of elongation. Elongation (controlled release of energy) can be provided, which can be set to a specific rate. Mechanical springs do not have this capability. In fact, self-locking gas springs work to perform multiple functions simultaneously (usually two: one through most of the stretch stroke, and one to provide damping at the end of the stretch stroke).
When designing a self-locking gas spring, a force loss of 1% to 2% must be allowed every year, and the force change caused by temperature should be known.
