### Car suspension

suspensionrear suspensionsuspension system
F is the force the spring exerts. k is the spring rate of the spring. x is the deflection of the spring from its equilibrium position (i.e., when no force is applied on the spring). Leaf spring – AKA Hotchkiss, Cart, or semi-elliptical spring. Torsion bar suspension. Coil spring. Rubber bushing. Gas under pressure - air spring. Gas and hydraulic fluid under pressure - hydropneumatic suspension and oleo strut. Satchell link. Panhard rod. Watt's linkage. WOBLink. Mumford linkage. Leaf springs used for location (transverse or longitudinal). Fully elliptical springs usually need supplementary location links and are no longer in common use.

### Helix

helicalheliceshelically
Examples of helices are coil springs and the handrails of spiral staircases. A "filled-in" helix – for example, a "spiral" (helical) ramp – is called a helicoid. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word helix comes from the Greek word ἕλιξ, "twisted, curved". Helices can be either right-handed or left-handed. With the line of sight along the helix's axis, if a clockwise screwing motion moves the helix away from the observer, then it is called a right-handed helix; if towards the observer, then it is a left-handed helix.

### Potential energy

potentialpotential energiesgravitational potential
A horizontal spring exerts a force F = (−kx, 0, 0) that is proportional to its deformation in the axial or x direction. The work of this spring on a body moving along the space curve s(t) = (x(t), y(t), z(t)), is calculated using its velocity, v = (v x, v y, v z ), to obtain :For convenience, consider contact with the spring occurs at t = 0, then the integral of the product of the distance x and the x-velocity, xv x, is x 2 /2. The function :is called the potential energy of a linear spring. Elastic potential energy is the potential energy of an elastic object (for example a bow or a catapult) that is deformed under tension or compression (or stressed in formal terminology).

### Watch

wristwatchwatcheswristwatches
Traditional mechanical watch movements use a spiral spring called a mainspring as a power source. In manual watches the spring must be rewound periodically by the user by turning the watch crown. Antique pocketwatches were wound by inserting a separate key into a hole in the back of the watch and turning it. Most modern watches are designed to run 40 hours on a winding and thus must be wound daily, but some run for several days and a few have 192-hour mainsprings and are wound weekly. A self-winding or automatic watch is one that rewinds the mainspring of a mechanical movement by the natural motions of the wearer's body.

### Torque

moment armmomentlever arm
Torque, moment, moment of force or "turning effect" is the rotational equivalent of linear force. The concept originated with the studies by Archimedes of the usage of levers. Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object. Another definition of torque is the product of the magnitude of the force and the perpendicular distance of the line of action of force from the axis of rotation. The symbol for torque is typically, the lowercase Greek letter tau. When being referred to as moment of force, it is commonly denoted by M.

### Shock absorber

shock absorbersdampersdamper
Spring-based shock absorbers commonly use coil springs or leaf springs, though torsion bars are used in torsional shocks as well. Ideal springs alone, however, are not shock absorbers, as springs only store and do not dissipate or absorb energy. Vehicles typically employ both hydraulic shock absorbers and springs or torsion bars. In this combination, "shock absorber" refers specifically to the hydraulic piston that absorbs and dissipates vibration. Now, composite suspension system are used mainly in 2 wheelers and also leaf spring are made up of composite material in 4 wheelers. In common with carriages and railway locomotives, most early motor vehicles used leaf springs.

### Clock

timepiecemechanical clockanalog clock
Clement also introduced the pendulum suspension spring in 1671. The concentric minute hand was added to the clock by Daniel Quare, a London clockmaker and others, and the second hand was first introduced. In 1675, Huygens and Robert Hooke invented the spiral balance spring, or the hairspring, designed to control the oscillating speed of the balance wheel. This crucial advance finally made accurate pocket watches possible. The great English clockmaker, Thomas Tompion, was one of the first to use this mechanism successfully in his pocket watches, and he adopted the minute hand which, after a variety of designs were trialled, eventually stabilised into the modern-day configuration.

### Balance wheel

foliotbalancecompensation balance
It is a weighted wheel that rotates back and forth, being returned toward its center position by a spiral torsion spring, the balance spring or hairspring. It is driven by the escapement, which transforms the rotating motion of the watch gear train into impulses delivered to the balance wheel. Each swing of the wheel (called a 'tick' or 'beat') allows the gear train to advance a set amount, moving the hands forward. The balance wheel and hairspring together form a harmonic oscillator, which due to resonance oscillates preferentially at a certain rate, its resonant frequency or 'beat', and resists oscillating at other rates.

### Glossary of mechanical engineering

Coil spring – also known as a helical spring, is a mechanical device which is typically used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. They are made of an elastic material formed into the shape of a helix which returns to its natural length when unloaded. Combustion –. Composite material – (also called a composition material, or shortened to composite), is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components.

### Bogie

trucksbogiestruck
The leaf springs were replaced by coil springs (one per wheel) running vertically rather than horizontally. The advanced design gave a better ride quality than the BR1, being rated for 100 mph. The side frame of the bogie was usually of bar construction, with simple horn guides attached, allowing the axle boxes vertical movements between them. The axle boxes had a cast-steel equaliser beam or bar resting on them. The bar had two steel coil springs placed on it and the bogie frame rested on the springs. The effect was to allow the bar to act as a compensating lever between the two axles and to use both springs to soften shocks from either axle.

### Spring steel

SAE 1095springySAE 1075
Many grades of steel can be hardened and tempered to suit application as a spring; however, some steels exhibit more desirable characteristics for spring applications. * Martensite Bibliography * Applications include piano wire (also known as music wire) such as ASTM A228 (0.80–0.95% carbon), spring clamps, antennas, springs, and vehicle coil springs, leaf springs, and s-tines. Spring steel is also commonly used in the manufacture of metal swords for stage combat due to its resistance to bending, snapping or shattering. Spring steel is one of the most popular materials used in the fabrication of lockpicks due to its pliability and resilience.

### Elasticity (physics)

elasticityelasticelasticity theory
As noted above, for small deformations, most elastic materials such as springs exhibit linear elasticity and can be described by a linear relation between the stress and strain. This relationship is known as Hooke's law. A geometry-dependent version of the idea was first formulated by Robert Hooke in 1675 as a Latin anagram, "ceiiinosssttuv". He published the answer in 1678: "Ut tensio, sic vis" meaning "As the extension, so the force", a linear relationship commonly referred to as Hooke's law. This law can be stated as a relationship between tensile force F and corresponding extension displacement x,:F=k x,where k is a constant known as the rate or spring constant.

### Hooke's law

spring constantforce constantelasticity tensor
Series and parallel springs. Spring system. Simple harmonic motion of a mass on a spring. Sine wave. Solid mechanics. Spring pendulum. Walter Lewin explains Hooke's law. From. A test of Hooke's law. From.

### Clockwork

clockwork motorclockworksClockwork Doll
A clockwork mechanism is often powered by a clockwork motor consisting of a mainspring, a spiral torsion spring of metal ribbon. Energy is stored in the mainspring manually by winding it up, turning a key attached to a ratchet which twists the mainspring tighter. Then the force of the mainspring turns the clockwork gears, until the stored energy is used up. The adjectives wind-up and spring-powered refer to mainspring-powered clockwork devices, which include clocks and watches, kitchen timers, music boxes, and wind-up toys.

### Force

forcesattractiveelastic force
Not until 1798 was Henry Cavendish able to make the first measurement of G using a torsion balance; this was widely reported in the press as a measurement of the mass of the Earth since knowing G could allow one to solve for the Earth's mass given the above equation. Newton, however, realized that since all celestial bodies followed the same laws of motion, his law of gravity had to be universal.

### Robert Hooke

HookeDr Robert HookeHooke, Robert
In 1660, Hooke discovered the law of elasticity which bears his name and which describes the linear variation of tension with extension in an elastic spring. He first described this discovery in the anagram "ceiiinosssttuv", whose solution he published in 1678 as "Ut tensio, sic vis" meaning "As the extension, so the force." Hooke's work on elasticity culminated, for practical purposes, in his development of the balance spring or hairspring, which for the first time enabled a portable timepiece – a watch – to keep time with reasonable accuracy.

### Pocket watch

pocketwatchwatch fobfob watch
The fusee is a specially cut conical pulley attached by a fine chain to the mainspring barrel. When the spring is fully wound (and its torque the highest), the full length of the chain is wrapped around the fusee and the force of the mainspring is exerted on the smallest diameter portion of the fusee cone. As the spring unwinds and its torque decreases, the chain winds back onto the mainspring barrel and pulls on an increasingly larger diameter portion of the fusee. This provides a more uniform amount of torque on the watch train, and thus results in more consistent balance amplitude and better isochronism.

### Harmonic oscillator

harmonic oscillatorsharmonic oscillationdamped harmonic oscillator
If the initial displacement is A, and there is no initial velocity, the solution of this equation is given by Given an ideal massless spring, m is the mass on the end of the spring. If the spring itself has mass, its effective mass must be included in m. In terms of energy, all systems have two types of energy: potential energy and kinetic energy. When a spring is stretched or compressed, it stores elastic potential energy, which then is transferred into kinetic energy. The potential energy within a spring is determined by the equation U = kx^2/2. When the spring is stretched or compressed, kinetic energy of the mass gets converted into potential energy of the spring.

### Yield (engineering)

yield strengthyield stressyield
Yield load can be taken as the load applied to the center of a carriage spring to straighten its leaves. The offset yield point (or proof stress) is the stress at which 0.2% plastic deformation occurs. In the three-dimensional principal stresses, an infinite number of yield points form together a yield surface. It is often difficult to precisely define yielding due to the wide variety of stress–strain curves exhibited by real materials. In addition, there are several possible ways to define yielding: The theoretical yield strength can be estimated by considering the process of yield at the atomic level.

### Torsion pendulum clock

Anniversary clockclock springKundo
For other use, see Kundo (disambiguation)'' A torsion pendulum clock, more commonly known as an anniversary clock or 400-day clock, is a mechanical clock which keeps time with a mechanism called a torsion pendulum. This is a weighted disk or wheel, often a decorative wheel with 3 or 4 chrome balls on ornate spokes, suspended by a thin wire or ribbon called a torsion spring (also known as "suspension spring"). The torsion pendulum rotates about the vertical axis of the wire, twisting it, instead of swinging like an ordinary pendulum. The force of the twisting torsion spring reverses the direction of rotation, so the torsion pendulum oscillates slowly, clockwise and counterclockwise.

### Fusee (horology)

fuseefuseeschain and fusee
The fusee was a good mainspring compensator, but it was also expensive, difficult to adjust, and had other disadvantages: Achieving isochrony was recognised as a serious problem throughout the 500-year history of spring-driven clocks. Many parts were gradually improved to increase isochronism, and eventually the fusee became unnecessary in most timepieces. The invention of the pendulum and the balance spring in the mid-17th century made clocks and watches much more isochronous, by making the timekeeping element a harmonic oscillator, with a natural "beat" resistant to change.

### Air gun

air rifleair pistolairgun
The advantages of the gas spring include the ability to keep the gun cocked and ready to fire for extended periods of time without long-term spring fatigue, no twisting torque (caused by coil spring expanding) being exerted onto the gun, smoother recoil pattern and faster "lock time" (the time between pulling the trigger and the pellet being discharged), which all result in more consistent accuracy. Gas springs perform more reliably in cold climates, as the grease used to lubricate coil springs often overthickens in low temperatures, causing the gun to "freeze up".

### Escapement

detent escapementCross-beat escapementduplex escapements
Without a balance spring, the crossbeat would have been no more isochronous than the verge. Invented around 1657 by Robert Hooke, the anchor (see animation at top of page) quickly superseded the verge to become the standard escapement used in pendulum clocks through the 19th century. Its advantage was that it reduced the wide pendulum swing angles of the verge to 3–6°, making the pendulum nearly isochronous, and allowing the use of longer, slower-moving pendulums, which used less energy.

### Pneumatics

pneumaticpneumaticallycompressed air
The hydraulic working fluid is basically incompressible, leading to a minimum of spring action. When hydraulic fluid flow is stopped, the slightest motion of the load releases the pressure on the load; there is no need to "bleed off" pressurized air to release the pressure on the load. Highly responsive compared to pneumatics. Supply more power than pneumatics. Can also do many purposes at one time: lubrication, cooling and power transmission. And Units. Or Units. 'Relay or Booster' Units. Latching Units. 'Timer' Units. Fluidics amplifiers with no moving parts other than the air itself. Compressed air. Ozone cracking - can affect pneumatic seals. Pneudraulics. History of pneumatic power.