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What are technical springs (metal springs)?
Technical springs are technical components made of spring steel that can deform elastically. When loaded, they yield and absorb force. When unloaded, they release this energy and return to their original shape. Steel springs, metal springs, or technical springs come in a wide variety of shapes and materials and are designed for different applications. Springs are made , among other things , from spring strip steel, spring steel sheet, or spring steel wire. In addition, technical springs can be manufactured from rubber and fiber-reinforced plastics, as well as gas springs, which use gases to provide spring action. Most spring types are named for their appearance. They are called shaped springs, strip springs, flat springs, leaf springs , spring clips or spring clamps , coil springs , disc springs, wave springs, conical springs , barrel springs , or ring springs . In addition, there are spring types that owe their name to their respective function. Examples of these are compression springs , extension springs , torsion springs , or torsion bar springs.
How do the technical springs differ from one another?
In addition to their shape and material, springs are defined by their spring constant or spring characteristic curve. The spring constant describes the increase in force in relation to the spring displacement or the angle of rotation. The spring characteristic curve illustrates the variation of the spring constant. It represents the relationship between spring force and displacement. Elastic deformation occurs in accordance with Hooke’s law. This law describes the elastic deformation of solids when the deformation is proportional to the applied load. Most types of springs have a linear spring characteristic curve (2) with a uniform force curve, a progressive characteristic curve (1), in which the force increases as deformation increases, or a degressive characteristic curve (3), in which the force decreases during this process. In addition, there are combined spring characteristics (5), which change their force properties under certain stress conditions or travel distances, and flat spring characteristics with a slight increase in force (4).
Areas of Application
As elastic components, technical springs yield under load and return to their original shape when the load is removed. Nearly all applications involving technical springs are based on this function. Among other things, they are used to move machine parts and to close or open switch contacts. When preloaded, they can be used as a driving force or as a restoring force in switches and torque wrenches. They are also used as force-fit connections —for example, in door stops or friction clutches, for load distribution in a trampoline, or in oscillating systems where spring systems convert kinetic energy into potential energy and absorb it.
A selection of the most important types of metal springs:
Leaf Springs
For a long time, the term “leaf spring” was used as an umbrella term for suspension springs made of flat material, such as full-elliptical springs, half-elliptical springs, and parabolic springs. Today, the term “leaf spring” also refers to technical springs, which are broadly classified as straight, curved, coiled, or disc-shaped flat springs.
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Straight flat springs
Straight flat springs can be stamped from spring steel strip and shaped using a stamping or stamping-bending machine. For small production runs or particularly intricate shapes, they can be laser-cut or etched. Straight flat springs are frequently used in the contact systems of electrical switching devices —for example, in relays. This allows contact springs to be installed in a preloaded state. CuSn6 spring bronze and CuBe2 copper-beryllium are frequently used in the manufacture of contact springs.
Curved Flat Springs and Shaped Springs
Generally, a distinction is made between curved flat springs and shaped springs. The curved flat spring consists of straight sections and circular arc sections. It is typically stamped from spring steel strip using an automatic stamping and bending machine and shaped at the same time. Shaped springs, on the other hand, are usually cut from spring steel sheet into their basic shape using laser cutting and then formed through bending, stamping, edge forming, and deep drawing. The variety of shapes—and thus the range of applications—is virtually unlimited. Calculating the forces acting on the springs is complex and can be performed using the finite element method (FEM). Feasible dimensions must be approximately determined manually in advance. There are no universally applicable calculation models. Design guidelines are therefore important, particularly those specifying the minimum bending radii that must be observed.
Coiled Flat Springs: Coil Springs and Roll Springs
Coiled flat springs include spiral springs —with and without wide coil spacing—as well as coil springs. Spiral springs are manufactured on radial bending machines. They play a significant role in the automotive industry, among others, where they are used in seat belts, window regulators, and locks. Coil springs are used, for example, in spring-loaded systems. Coiled flat springs are ideal as compensating springs for small angles of rotation. The stored force serves as a compensating or restoring torque. The spring characteristic curve rises almost linearly. Both spring types are coiled in a single plane according to the Archimedean spiral. A constant coil pitch ensures that the individual coils do not touch one another and also guarantees low-friction operation of the springs.
More information about coil springs
Disc-shaped flat springs
Disc-shaped flat springs include disc springs, spring washers, and lock washers. They are used either as individual springs or in combination. Spring washers are devices that are suitable for certain screw connections. Disc springs are characterized by their high force and are also particularly compact. As a result, they are often used in confined spaces where high forces are required. Disc springs can be manufactured using a stamping process followed by cold forming and edge rounding. A unique feature: the force and spring travel can be adjusted by stacking them to form a disc spring column. Disc springs produce a degressive spring characteristic curve.
Spring Clamps: Spring Clips, Clamping Springs, and Pipe Clamps
Spring clips – also known as spring clamps , clamping springs , or pipe clamps – are stamped and formed from spring steel strip or laser-cut from spring steel sheet and then shaped. Their main characteristic is the force-fit connection . They are used where components need to be adjusted, locked, snapped into place, or fixed. Among other things, they serve to hold papers, secure name tags, or as a replacement for paper clips. They are also suitable for hanging tools, hoses, and similar items.
Wave springs
Wave springs are also known as axial wave springs or corrugated springs. They are made of coiled flat wire and derive their spring action from the integrated corrugation. With an installation height reduced by up to 50 percent compared to conventional compression springs, they offer a space-saving alternative for static to moderately dynamic applications. Despite this reduced installation height, wave springs can generate the same force as compression springs, for example. The required spring constant can be determined and achieved by varying the number of coils, the number of waves, and the wave sizes.
Torsion Springs
Torsion springs, or leg springs, are coiled wire springs with legs extending tangentially from the coil. These mechanical energy storage devices absorb torque at the legs during angular and rotational motion, which they release again when uncoiled. Torsion springs are manufactured from round, oval, or square spring steel wire—typically cylindrical in shape with a uniform pitch and no gaps between the coils. Depending on the application, the legs can extend, for example, straight tangentially, radially inward or outward, axially, or parallel to the axis. It is particularly important to note that torsion springs should only be loaded in the direction of the coils. For this reason, they are offered in identical designs with left-hand and right-hand coiling.
Compression springs
Compression springs, also known as coil springs, are mechanical energy storage devices that absorb forces when compressed and release them when relaxed. They are manufactured from round, oval, or square spring steel wires—typically cylindrical in shape and with a uniform pitch. The spring steel wire is cold-formed. This is done either by winding around a mandrel (single-finger system) or, in the case of fully automatic spring winding machines (video: spring production at Gutekunst), with the aid of wire guide pins (two-finger or three-finger system). Unlike conventional compression springs with a constant pitch, the coil spacing can vary. This affects the spring characteristic curve. To prevent the compression springs from snagging, coils in the middle or at the ends of the spring are often wound in a solid block.
Conical Springs
In a conical spring, the diameter of the spring changes toward one end. This means it becomes larger or smaller. Conical springs are primarily used when the installation space is limited in the axial direction. In conical compression springs, the coils can nest inside one another. As a result, the block height is approximately twice the wire diameter and is therefore significantly smaller than that of cylindrical compression springs. These springs can be designed with either a linear or a progressive spring constant. Normally, the spring rate or spring constant is progressive. This means that the spring force increases as the load increases.
Torsion springs
The barrel spring is also known as a double-conical compression spring. Both ends of the spring have a smaller coil diameter than the center. Barrel springs typically have a linear and progressive load-to-deflection curve. They also offer the advantages of a small footprint and short overall length. A special type of double-conical compression spring is the miniblock spring. It has an adjusted coil diameter. As soon as the miniblock spring is compressed to a short length, the main part of the coils nestle inside one another—without coming into contact. This type of spring is often used in a car’s suspension system. Depending on the application, it can provide either a linear spring rate with varying coil diameters or a progressive, increasing spring rate with consistent coil diameters.
Tension springs
Tension springs or coiled tension springs are manufactured from round or oval spring steel wires. These can be shaped into the desired form through a cold forming process—by coiling them around a mandrel or using fully automatic spring coiling machines with the aid of multiple wire guide pins. In addition to cylindrical designs with a linear spring rate, conical or barrel-shaped tension springs are also manufactured. These tapered spring ends not only provide a progressive spring rate but also extend the springs’ service life. Depending on the application, the user can choose from various eyelet shapes. In addition to classic eyelet shapes, such as the 1/1 German eyelet or hook eyelet, the product range also includes durable spring ends. These include rolled-in threaded bolts or screw-in threaded plugs.
Snap rings
In mechanical engineering, snap rings secure form-fit components—such as gears, seals, and bearings—to axles, shafts, or within bores, preventing them from shifting axially. The term “retaining ring” derives from the earlier method of manufacture. Back then, they were cut from tubes and then split open. Today, snap rings are made of spring steel wire with a uniform cross-section. They are bent into a ring using an automatic winding machine. Their diameter can range from a few millimeters to several meters. Snap rings are available in two basic designs: for shafts and for bores.
Torsion Springs: Torsion Bar Springs
The torsion bar is a type of torsion spring. The term “torsion spring” is derived from the verb “to twist,” which means to bend or turn. Torsion bars are used, for example, as torsion pendulums in mechanical watches, as torsion bands in moving-coil measuring instruments, as stabilizers in vehicle suspensions, and as counterforces in sectional garage doors. The torsion bar spring has an elongated, rod-shaped structure and performs a rotational movement during operation. When the rod is twisted about its own longitudinal axis, a shear stress is generated. This stress increases with the cross-sectional radius and is proportional to the torsional moment. The distribution of the shear stress is rotationally symmetric within the bar’s cross-section. The angle of twist is also proportional to the torsional moment and increases linearly with the bar’s length.
Custom Spring Applications
Do you need a technical spring for your special application? Then simply send us the desired spring data – regardless of the type of spring – in the form of dimensional data, sketches, drawings or CAD data using the following Spring inquiry button or via email info@gutekunst-formfedern.de to. Our experts will be happy to make you an individual offer for the right technical spring.
Benefit from the new Formfedern store
The new form spring store from Gutekunst Formfedern offers several advantages in the procurement of form springs, flat springs, laser parts and sheet metal parts. Thanks to its simple operation, transparent online price calculation and fast digital processing, it is a real support for designers, technicians and purchasers. At last, it is possible to configure, calculate prices, make inquiries and place orders for tailor-made formed metal parts in an uncomplicated and time-saving manner – around the clock and with maximum transparency.
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