Glossary
Alloy
A metal composed of two or more elements bound together
Angular relationship of ends
The relative position of the plane of the hooks or loops of extension springs to each other
Arbor
A round, hardened rod or shaft upon which springs are wound., Also called a "mandrel"
Baking
Heating of electroplated springs to relieve hydrogen embrittlement
Belleville Springs
These are essentially initially coned disk, who may be stacked up to give a variety of load-deflection characteristics
Blue
A thin blue film of oxide on ferrous alloys, sometimes used to indicate that the material has been stress relieved
Brass
A copper-base alloy of copper and zinc
Bronze
A copper-base alloy of copper and tin
Buckling
Bowing or lateral deflection of compression springs when compressed, related to the slenderness ratio
Ceramic Spring
Spring made of ceramics as called by its material
Circlip
Generic term for circular springs, such as C-type retaining ring
Closed ends
Ends of springs where the pitch of the end coils is reduced so that the end coils touch
Close-wound
Coiled with adjacent coils touching
Cold Formed Spring
Spring formed in low temperature, such as the cold formed coil compression spring and the cold formed coil extension spring as called by its forming method
Combination Spring
Combination of Multiple springs to obtain the required characteristics. (Springs may be combined in a serial or parallel way. A combination spring comprising two springs is called serial double spring or parallel double spring.)
Composite Resin Spring
Spring made of composite rresin materials, as called by its material
Compression Spring
Spring subjected mainly to a compressive force, in the narrow sense, helical compression spring
Compressive stress
Is the stress state when the material tends to compact (volume decrease). A simple case of compression is the uniaxial compression induced by the action of opposite, pushing forces. Most materials can carry compressive stress
Constant Force Spring
Spring that indicates constant load or torque despite of the deflection change
Constant Rate Spring
Spring deflection of which is linear to the load applied
C-Type Concentric Retaining Ring
Concentric retaining ring shaped like "C", including two types: for one-shaft-use and for in-bore-use
C-Type Eccentric Retaining Ring
Eccentric retaining ring shaped like "C", including two types: for one-shaft-use and for in-bore-use.
Deflection
Motion of the spring ends or arms under the application or removal of an external load
Ductility
Being capable of sustaining large plastic deformations without fracture. It is characterized by the material flowing under shear stress
Elastic deformation
Is the spring-like deformation, where a material will return to its original shape
Elastic limit
Maximum stress to which a material may be subjected without permanent set
Elastic modulus
See Young's modulus
Endurance limit
Maximum stress at which any given material will operate indefinitely without failure for a given minimum stress
E-Type Retaining Ring
Retaining ring shaped like "E" for on-shaft-use.
Extension Spring
Spring subjected mainly to an extensive force, in the narrow sense, helical extension spring
Fastener Spring
Various shapes of spring for fastening
Fatigue
Is a process by which a material is weakened by cyclic loading. The resulting stress may be below the ultimate tensile stress
Flat Spring
Various shapes of spring made of thin flat materials, as called by its material
Fluid Spring
Spring using the elasticity of gas or liquid, as called by its material
Formed Wire Spring
Various shapes of springs made of wire, as called by its material
Fracture
Is the separation of a body into two, or more, pieces under the action of stress
Free Angle
Angle between the arms of a torsion spring when the spring is not loaded
Free length
The overall length of a spring in the unloaded position
Frequency (natural)
The lowest inherent rate of free vibration of a spring itself (usually in cycles per second) with ends restrained
Gas Spring
Spring using the elasticity of inert gas such as Argon or Helium, which is one of the fluid springs
Gauge
Standards for measuring material thickness or diameter for non-metric units of measure
Gradient (Rate)
Change in force per incremental unit of deflection e.g. gm per mm, Newton per mm, gm-mm per degree
Grip Ring
Retaining ring used for shafts without grooves
Ground ends
Ends of springs are ground to provide a flat plane
Heat setting
Fixturing a spring at elevated temperature to minimize loss of load at operating temperature
Helical Torsion Springs
Helical torsion springs are loaded by a torque about the helix axis. To transmit this torque special ends are normally required.
Helix
The spiral form (open or closed) of compression, extension, and torsion springs
Hole
This is the minimum diameter of the hole in which spring can work
Hooks
Open loops or ends of extension springs
Hot Formed Spring
Spring formed in low temperature, such as the cold formed coil compression spring and the cold formed coil extension spring, as called by its forming method
Hot-wound springs
Having large bar diameters > 16mm and above. They are widely used in automotive and railroad equipment
Hydrogen embrittlement
Hydrogen absorbed in electroplating or pickling of carbon steels, tending to make the spring material brittle and susceptible to cracking and failure, particularly under sustained loads
Hydropneumatic Spring
Spring using the elasticity of gas or liquid, as called by its material
Hysteresis
The mechanical energy loss that always occurs under cyclic loading and unloading of a spring, proportional to the area between the loading and unloading load-deflection curves within the elastic range of a spring
Initial tension
The force that tends to keep the coils of an extension spring closed and which must be overcome before the coil starts to open
Leaf springs
These springs consist of flat bars of varying lengths clamped together to obtain greater efficiency and resilience
Linear load deflection
Deflection is proportional to the load, when load is doubled, the deflection will be doubled e.g. typical compression springs
Load
The force applied to a spring that causes a deflection
Lock Washer
Generic term for washers for locking using the spring action
Loops
Coil-like wire shapes at the ends of extension springs that provide for attachment and force application
Magnetic Spring
Spring using the repulsion force and attraction force by magnetism, as called by its type of function
Mean coil diameter
Outside wire diameter minus one wire diameter
Mechanical spring
Elastic body, whose primary function is to deflect or distort or absorb energy under load and which recovers its original shape when released
Metallic Spring
Spring made of metallic materials as called by its material
Modulus in shear or torsion (G)
Coefficient of stiffness for extension and compression springs
Modulus in tension or bending (E)
Coefficient of stiffness used for torsion and flat springs (Young's Modulus)
Modulus of elasticity
See Young's modulus
Modulus of rigidity
See Shear modulus
Moment (M)
See Torque
Nonferrous Metal Spring
Spring made of nonferrous metal, as called by its material
Nonlinear load Functions of springs
To absorb energy and mitigate shock, to apply a definite force or torque, to support moving masses or isolate vibration, to indicate or control load or torque
Nonlinear Spring
Spring the deflection of which is not linear to the load applied
Non-Metallic Spring
Spring made of non-metallic materials as called by its material
Open ends ground
Open ends ground
Open ends, not ground
End of a compression spring with a constant pitch for each coil.
Passivating
Acid treatment of stainless steel to remove contaminants and improve corrosion resistance
Permanent set
A material that is deflected so far that its elastic properties have been exceeded and it does not return to its original condition upon release of load is said to have taken a "permanent set"
Pitch
The distance from center to center of the wire in adjacent active coils
Plastic deformation
The non-reversible change of shape in response to an applied force
Pneumatic Spring
Spring using the elasticity of air, which is one of the fluid springs
Progressive Rate Spring
Spring the deflection of which is not linear to the load applied
Proportional Limit
Maximum load at which strain or deformation is directly proportional to stress, at zero percent offset
Rate (R)
Change in load per unit deflection, generally given in pounds per inch
Relaxation
The opposite of stress or tension
Remove set
The process of closing to solid height a compression spring which has been coiled longer than the desired finished length, so as to increase the apparent elastic limit
Residual stress
Stresses induced by set removal, shot peening, cold working, forming or other means. These stresses may or may not be beneficial, depending on the application
Resilience
Elastic ability of a material to rebound to its original shape after deflection
Retaining Ring
Circular spring for preventing the axial movement by snapping into the groove formed on the shaft or the hole
Rubber Spring
Spring using the elasticity of rubbers, as called by its material
Set
Permanent distortion which occurs when a spring is stressed beyond the elastic limit of the material
Shaft
This parameter describes the maximum diameter of spring shaft in industrial applications
Shear modulus G
Is defined as the ratio of shear stress to the shear strain
Shear strain
Is the components of a strain at a point that produce changes in shape of a body (distortion) without a volumetric change
Shear stress
Is caused when a force is applied to produce a sliding failure of a material along a plane that is parallel to the direction of the applied force
Shot peening
A cold-wound process in which the material surface is peened to induce compressive stresses and thereby improve fatigue life
Slenderness ratio
Ratio of spring length to mean coil diameter
Snap Ring
Circular spring for preventing the axial movement by snapping into the groove formed on the shaft or the hole
Solid height
Length of a compression spring when under sufficient load to bring all coils into contact with adjacent coils
Spiral springs
Formed of flat strip wound in the form of a spiral (clock or power springs), such springs are loaded by torque about an axis normal to the plane of the spiral
Spring
Mechanical element designed mainly to unitse by elasticity or distoriion of an object
Spring index
Ratio of mean coil diameter to wire diameter
Spring rate (R)
This parameter determines spring's resistance, while it is working
Spring Washer
Generic term for washers for locking using the spring action
Squareness of ends
Angular deviation between the axis of a compression spring and a normal to the plane of the ends
Squareness under load
As in Squareness of ends, except with the spring under load
Static loading
Loading the springs with steady load
Steel Spring
Spring made of steel materials as called by its material
Stiffness
Is the resistance of an elastic body to deflection by an applied force. Stiffness is typically measured in Newton’s per meter
Strain
Deformation caused by the action of stress on a solid material. Strain therefore expresses itself as a change in size and/or shape
Stress
The force that is exerted on a solid material from the outside
Stress range
The difference in operating stresses at minimum and maximum loads
Stress relieve
To subject springs to low-temperature heat treatment so as to relieve residual stresses
Tensile strength (Rm)
The maximum amount of stretching stress a material can withstand before it tears. Materials rated at a high tensile strength are durable and difficult to tear
Tensile stress
Is a loading that tends to produce stretching on a material by the application of axially directed pulling forces. Materials can withstand some tensile loading, but if enough force is applied, they will eventually break into two parts
Torsion Spring
Twisting spring subjected mainly to a twisting moment, in the narrow, sense, helical torsion spring
Torsion-bar Springs
These are essentially straight bars under torsion, the load usually being applied through splined ends
Total number of coils
Number of active coils plus the coils forming the ends
Variable Rate Spring
Spring the deflection of which is not linear to the load applied
Wahl Factor
A factor to correct stress in helical springs effects of curvature and direct shear
Waved Spring Washer
Spring washer made by turning wire and formed into a waved shape
Waved Washer
Spring washer made of thin ring plate on which waving is formed
Wire Forming
Various shapes of springs made of wire, as called by its material
Wire Spring
Coil spring made of wire
Yield point
See Yield strength
Yield strength
The amount of strain that a material can undergo before moving from elastic deformation into plastic deformation. The stress felt by a material given a certain strain is defined by linear relationship
Young's modulus
Is a measure of the stiffness of a given material, That is how hard it is to stretch chemical bonds that bind the atoms of a material together