Like screws, springs are frequently used mechanical components used in various devices such as automobiles, electrical products, and daily necessities. This section introduces an overview on springs and introduces observation and measurement examples using a digital microscope.
- Typical spring types
- Compression coil spring materials and dimensions
- Observation and measurement examples of springs using a digital microscope
Typical spring types
- Compression coil springs
Compression coil springs generate a repulsive force when loaded in the compression direction. The structure either has an equal pitch or a taper. This type of spring is commonly used as suspension springs in automobiles.
- Tension coil springs
Tension coil springs generate a repulsive force when loaded in the extension direction. Hooks are included on both ends of the spring. This type of spring is commonly used in bicycle stands and measuring devices.
- Torsion coil springs
Torsion coil springs generate a repulsive force when the coil is subjected to torsional movement around the spring’s central axis. Hooks may be included on both ends of the spring. This type of spring is commonly used in door locks and hole punches.
Compression coil spring materials and dimensions
Coil spring materials
- Hardened steel wire
- This is the least expensive of all metal spring materials and is used in various everyday products.
- Piano wire
- Offering higher tensile strength than hardened steel wire and greater hardness and fatigue resistance reliability, piano wire is commonly used for industrial springs.
- Stainless steel
- Stainless steel offers better corrosion and heat resistance than piano wire, making it a mainstay of coil springs.
Compression coil spring dimensions
- Dimension description
Dimension Description Wire diameter The diameter of the wire used for the spring.
Symbol: d (mm/inch)
Average coil diameter The average of the outer and inner coil diameters.
Symbol: D (mm/inch)
Outer coil diameter The diameter of the outer edge of the coil.
Symbol: Do (mm/inch)
Inner coil diameter The diameter of the inner edge of the coil.
Symbol: Di (mm/inch)
Free height The height of the spring with no load.
Symbol: Hf (mm/inch)
Active coils The number of coils used by the spring to generate force.
Total number of coils The number of all coils between both ends of the spring.
Pitch The distance between the centres of a helically wound wire.
Symbol: P (mm/inch)
Observation and measurement examples of springs using a digital microscope
The latest examples of observation and measurement of springs using KEYENCE’s VHX Series 4K Digital Microscope are introduced below.