Coil springs, called compression springs, store mechanical energy when compressed. These open coil springs provide resistance to compressive loads. When these springs are subjected to a compressive load, they compress, shorten and absorb a large amount of potential force. After the load is reduced or removed by the stored energy, the springs are forced to return to their original length and shape. Compression springs become more compact when weighted. In contrast to extension springs, the coils of compression springs do not touch when relaxed; instead, they compress tightly when stressed.
Automotive: It would be very difficult to build most cars without at least some stainless steel compression springs. Compression springs are used in various parts of the car, such as seats, hoses, and even the suspension. The seat uses bulk compression springs to fit the body and provide more comfort. Naturally, a variety of sizes and shapes are available to meet the wide variety of uses for automotive compression springs.
Door locks: Springs have traditionally been critical to the proper function of door locks. Due to the mechanism of the lock and key system, most metal locks contain some sort of steel spring which relies on the key release to hold the bolt in place and maintain pressure on the door lock. The spring creates this tension. Locksmiths have used compression locks for this purpose since the 1700's.
Pen: A stainless steel compression spring including 316 stainless steel compression springs can be observed by examining the ballpoint pen. This spring allows the pen to write while exposing the nib, which is then protected within the casing to prevent the ink from drying out. This makes it possible to use the pen without a bulky and easily lost cap.
Aviation: Most air travel would not be possible without multiple types of springs. Springs on an aircraft may not be visible, but air turbines, guidance systems, engine controls, wheels, brakes, gauges, fuel cells and diesel engines are just a few of the components on an aircraft that require springs.
Arms: Whenever you think about tension, think about compression springs. Consider the strain required to fire a bow. A crossbow is a simpler weapon if a compressed spring is used instead of the body stainless steel stamping part. Technological advancements continue in modern semi-automatic pistols, which use a compressed spring to absorb energy from recoil and redirect it to advance the slide or bolt and reload the weapon for subsequent shots.
Medical devices: Stainless steel compression springs are used in many medical device applications, from tiny springs in inhalers, pill dispensers, and syringes to many diagnostic tools. Additionally, there are springs for a variety of medical equipment including catheters, valves, peristaltic pumps, wheelchairs, endoscopic equipment, staplers, and surgical, orthopedic, and other tools.