Extension springs, also called tension springs, are springs which absorb and store energy by offering resistance to a pulling force. Usually, extension springs are attached at both ends to other components so; various types of ends are used to attach the extension spring to the source of the force.
Most extension springs are wound with initial tension. This is an internal force that holds the coils tightly together. The measure of the initial tension is the load necessary to overcome the internal force and just start coil separation. Unlike a compression spring, which has a zero load at zero deflection, an extension spring can have a preload at zero deflection. Moreover, contrasting with compression springs, extension springs do not have a solid stop to prevent overloading. Because of this design stress levels are lower for extension springs than for compression.
A special type of extension spring is “drawbar spring”, this spring has a solid stop and is a type of compression spring with special hooks. In a drawbar, the load is applied ate the ends of long steel loops which pass through the spring’s center and are hooked around the opposite end, thus compressing the spring upon loading. Drawbar springs are excellent for use in potential overload situations.
The variety of ends that can be put on extension springs is limited only by the imagination and may include threaded inserts, reduced and expanded eyes on the side or in the center of the spring, extended loops, hooks or eyes at varying positions or distances from the body of the spring and even rectangular or teardrop-shaped ends.
In Gestion de Compras we designs, develops and manufactures any kind of extension springs for multitude sectors and industries. Ours suppliers use state-of-art CNC spring coiling machines to produce high quality springs with the desired pitch, spring diameter, wire diameter, material, surface coating, etc.
Materials and products
Extension springs are typically metal because of the stiffness of the material. Hard drawn steel, music wire, spring steel, stainless steel and brass are most common, but other materials may be incorporated in custom applications for example specialty metals and alloys can be customized per application.
Extension springs have a wide range of applications; they are for example used in trampolines, automotive interiors and exteriors, carburetors, toys, washing devices, farm machinery, garage doors assemblies, vise-grip pliers, industrial robots, as well as thousands of other uses. Extension springs come in a wide array of sizes, from small medical devise to off-road machinery brake springs.
Standard and certificates
Our factories have the most demanding certifications for customers to ensure product quality as:
- ISO 9001, TS 16949 e ISO 14001.
- DIN 2089, DIN 2097, etc.