Compression springs ;are coil springs that hold mechanical energy in their compressed states. When these springs experience a compression load, they compress and become shorter, capturing and storing significant potential force. Once the load is diminished or removed, the stored energy forces the springs back to their original shapes and lengths.
Compression springs are helical—i.e., spiral-like—springs. When force isn’t applied to them, they demonstrate an open-coiled design. However, as pressure presses down along the axis of the spring, the coils push tighter against each other. This effect shortens the length of the spring and stores energy. Once the pressure ceases, the stored energy returns the spring to its original height.

The types of compression springs available include:

Convex springs

Convex springs (i.e., barrel-shaped springs) have coils with larger diameters in the middle of the spring and coils with smaller diameters on both ends. This design allows the coils to fit within each other when the spring is compressed. Manufacturers use convex springs in applications that require more stability and resistance to surging as the springs decompress. Most applications that use them are in the automotive, furniture, and toy industries.

Concave springs

Concave springs (i.e., hourglass springs) have narrower coils in the middle of the spring than on either end. The symmetrical shape helps ensure the springs stay centered over a particular point.

Conical springs

Conical springs (i.e., tapered springs) are shaped like cones. One end has a larger diameter than the other, and the coils throughout the spring provide a gradual taper or change in size. Some conical springs have enough change in diameter from the coil to the coil so that each coil fits into the previous one.

Straight coil springs

In these springs, every coil has the same diameter. Straight coils are some of the most common springs in use.

Variable pitch springs

Variable pitch springs have different distances between each coil up and down the length of the spring.

Volute springs

These springs are cone-shaped. However, instead of having wire coils, the coils are formed from a curved sheet of metal or other material.

What Is an Extension Spring?
Extension springs ;store energy and exert a pulling force between two mechanisms. When mechanisms separate, the extension spring tries to bring them together again. Extension springs use round wire to create a close-wound design with initial tension.

How Extension Springs Work

An extension spring’s ends attach between two mechanisms. The extension springs hooks and loops store and absorbs energy. Through hooks or loops, an extension spring provides return force to connected mechanisms. Tightly wound extension springs typically sit in the no-load position. More stress in the end hooks—as opposed to the spring body—limits the performance of extension springs.

Common Applications of Extension Springs

Extension springs use a variety of hook or loop end configurations to fit specific functions. Extension spring ends include threaded inserts, extended twist loops, crossover center loops, hooks, expanded eyes, reduced eyes, rectangular ends, and teardrop-shaped ends. Modify the length of hooks and the spring body distance for customized extension spring fits and functions. Find extension springs in a variety of everyday items, from garage doors to tools to washing machines to toys. The variety in size makes extension springs versatile as they are used in small medical devices and off-road machinery. ;

What Are Torsion Springs?
A torsion spring ;is a component made from an elastic material that, when twisted, exerts a moment resisting the rotation. Common types of torsion springs include helical torsion springs, torsion bars, and spiral wound torsion springs.

Helical torsion springs are made from a material, typically sprung steel spring wire, and formed into a helix. At each end, the helix extends to form two straight legs through which the torque is applied. A circular mandrill inside the coil, or a circular housing around the coil, is used to retail the position of the spring. The legs typically extend tangentially, which results in the lowest stresses. However, radial and axial legs are also used at times.

Helical torsion springs are used in a wide range of applications, with wire diameters ranging from fractions of a millimeter to over an inch. Light-duty torsion springs are typically used as return springs in electrical devices, whereas heavy-duty springs are used in applications such as folding seats and door returns

Torsion bars are simply straight bars of elastic material that can be twisted to their elastic limit. Torsion bars of typically constructed from steel or rubber. They are often used for heavy-duty applications, such as the suspension of trucks and tanks. ;

Torsion bar suspension is extremely durable because of its mechanical simplicity. It is also compact and allows for easy adjustments. Very light-duty torsion bars may require tension to generate a restoring torque, which is referred to as a torsion fiber.

A spiral wound torsion spring is formed from a spring wire, or more commonly a thin strip of sprung steel, coiled into a flat spiral. This configuration allows large angular deflections of many revolutions, with relatively little variation in torque during the movement. Spiral wound torsion springs are, therefore, used in clockwork devices, clocks, and other devices that require energy to be stored and consistently released in this way.

Power springs are a special type of spiral wound spring that can exert a consistent torque over many revolutions, they are sometimes referred to as clock springs or motor springs. Power springs are wound tightly within a case to provide a high energy density. ;

What Are ;Wire Forms?
Wire forms ;are finished-shaped wire that has been manufactured from wire spools into a specified configuration. They can take nearly any form, often featuring springs with custom ends, and can range in size from very small to very large. Essentially a wire form is a length of wire that has had an exterior force applied to it in order to create a specific shape designed for a specific job.

The wire form can be bent, cut, cut with angles, wound right/left, shaped with closed coils, can have additional pieces added to it, and just about anything that a customer can think of. Because of the versatility of wire forms, it is not an exaggeration to say that they can be found, in one form or another, in almost every industry.

What Are ;the Advantages or Benefits of Using Conical Coil Springs?
Conical coil springs ;are basically compression springs coiled in increasing or decreasing outer diameters thus making their shape a cone or tapered one. These springs tend to reduce the solid height and provide stability.

Conical coil springs are also known as tapered springs or cone springs. One of the advantages of tapered springs is that they provide stability to those sprigs that have a large slenderness ratio. The slenderness ratio defines whether the spring will bend or buckle during compression/deflection. A high slenderness ratio means that the compression spring’s free length is more than 4 times larger in comparison to the outer diameter. In other words, it has a 4 to 1 ratio. Its length is too long in proportion to its outer diameter and this, by laws of physics, will cause the spring to deform when it travels down to a desired solid height. Now let’s move on to the other benefit of conical compression springs; the reduction of the solid height.

Due to its tapered cone shape, some cone springs have the diameters adjusted to a point where they’ll perform a telescope effect when deflecting. The way to do this is by making sure that the inner diameter into which the next coil will compress is larger than the next coil’s outer diameter. This will cause the smaller coil’s outer diameter to compress into the larger coil’s inner diameter. If the spring has enough elasticity to compress to solid height, your spring’s solid height will be the size of the wire diameter since it will compress down to the last coil. If you don’t need such a small solid height, the smaller coil’s outer diameter doesn’t necessarily have to be smaller than the larger coil’s inner diameter since we are using a round wire. As you can see from the image to the right, the round wire still allows some telescope effect, giving you more travel space and a smaller solid height. This reduces the solid height as well but it will not produce a full telescope effect where the solid height equals your wire diameter.

http://www.zhlspring.com/compression-spring/