A counterweight is a weight that, by applying an opposite force, provides balance and stability of a mechanical system . The purpose of a counterweight is to make lifting the load faster and more efficient, which saves energy and causes less wear and tear on the lifting machine.
17-398: Counterweights are often used in traction lifts (elevators), cranes and funfair rides. In these applications, the expected load multiplied by the distance that load will be spaced from the central support (called the "tipping point") must be equal to the counterweight's mass times its distance from the tipping point in order to prevent over-balancing either side. This distance times mass
34-618: A life of 200 km, while those used on heavy trucks may have a life approaching 100,000 km. The truck tires have less traction and also thicker rubber. Traction also varies with contaminants. A layer of water in the contact patch can cause a substantial loss of traction. This is one reason for grooves and siping of automotive tires. The traction of trucks, agricultural tractors, wheeled military vehicles, etc. when driving on soft and/or slippery ground has been found to improve significantly by use of Tire Pressure Control Systems (TPCS). A TPCS makes it possible to reduce and later restore
51-635: A low noise level and good water removal. More lateral grooves usually increase traction . Sipes are small grooves that are cut across larger tread elements. Up to a point, more sipes give more traction in snow or mud. As is often the case, there are compromises. Winter tires , and "mud and snow" tires, may have thousands of sipes and give good traction, but they may feel "squirmy" on a warm, dry road. Unpatterned racing "slicks" on dry roads give maximum traction. These have no sipes, no grooves, and no tread blocks. However, they have very poor traction on even slightly wet surfaces. Large sipes are usually built into
68-745: A series of diagonal cuts across the tread. For improved traction, the tire may be siped twice, leaving diamond-shaped blocks. A significant problem with field siping is that the tread picks up rocks, glass, and other hard road debris in use, and even with thorough cleaning the knife service life is often poor. Microsiping can dramatically improve tire traction in rain and snow. However, microsiped tires may also have increased road noise and tire wear when operated on dry surfaces. Consumer Reports recommends against adding more than "the sipes that your tires come with" because of longevity and dry performance. Some companies such as Les Schwab claim that microsiped tires reduce tire friction heat and tire wear and extends
85-412: Is called the load moment . By extension, a counterbalance force balances or offsets another force, as when two objects of equal weight, power, or influence are acting in opposition to each other. Metronome : A wind-up mechanical metronome has an adjustable weight and spring mechanism that allows the speed to be adjusted by placement of the weight on the spindle. The tempo speed is decreased by moving
102-503: Is defined as the usable force for traction divided by the weight on the running gear (wheels, tracks etc.) i.e.: usable traction = coefficient of traction × normal force . Traction between two surfaces depends on several factors: In the design of wheeled or tracked vehicles, high traction between wheel and ground is more desirable than low traction, as it allows for higher acceleration (including cornering and braking) without wheel slippage. One notable exception
119-468: Is in the motorsport technique of drifting , in which rear-wheel traction is purposely lost during high speed cornering. Other designs dramatically increase surface area to provide more traction than wheels can, for example in continuous track and half-track vehicles. A tank or similar tracked vehicle uses tracks to reduce the pressure on the areas of contact. A 70-ton M1A2 would sink to the point of high centering if it used round tires. The tracks spread
136-436: The maximum tractive force between a body and a surface, as limited by available friction; when this is the case, traction is often expressed as the ratio of the maximum tractive force to the normal force and is termed the coefficient of traction (similar to coefficient of friction ). It is the force which makes an object move over the surface by overcoming all the resisting forces like friction , normal loads(load acting on
153-409: The 1920s, Sipe worked in a slaughterhouse and grew tired of slipping on the wet floors. He found that cutting slits in the tread on the bottoms of his shoes provided better traction than the uncut tread. Another story is that he was a deckhand and wanted to avoid slipping on a wet deck. John Sipe's invention was unsuccessful. It was applied to solid rubber tires, rather than pneumatic tires, and so
170-455: The 70 tons over a much larger area of contact than tires would and allow the tank to travel over much softer land. In some applications, there is a complicated set of trade-offs in choosing materials. For example, soft rubbers often provide better traction but also wear faster and have higher losses when flexed—thus reducing efficiency. Choices in material selection may have a dramatic effect. For example: tires used for track racing cars may have
187-454: The life of the tire. Both Bridgestone and Michelin sell snow tires that are siped at the factory, while Saf-Tee Siping and Grooving sells machines that can sipe most standard vehicle tires. Siping can also be done by hand. Siping tires may void the manufacturer's warranty. Claims that extended life is achieved by siping may only apply to certain environments, operating temperatures , and rubber compound builds. Fine slits are cut into
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#1732798617102204-511: The tiers in negative 'Z' axis), air resistance , rolling resistance , etc. Traction can be defined as: a physical process in which a tangential force is transmitted across an interface between two bodies through dry friction or an intervening fluid film resulting in motion, stoppage or the transmission of power. In vehicle dynamics, tractive force is closely related to the terms tractive effort and drawbar pull , though all three terms have different definitions. The coefficient of traction
221-582: The tire "footprint" on the road. A 1978 study by the US National Safety Council found siping improved stopping distances by 22 percent, breakaway traction by 65 percent, and rolling traction by 28 percent on glare ice . Since then, the council has retracted that study and is "not currently recommending or endorsing the siping procedure". Tire tread block shapes, groove configurations, and sipes affect tire noise pattern and traction characteristics. Typically, wide, straight grooves have
238-408: The tire pressure during continuous vehicle operation. Increasing traction by use of a TPCS also reduces tire wear and ride vibration. Siping (rubber) Siping is a process of cutting thin slits across a rubber surface to improve traction in wet or icy conditions. Siping was invented and patented in 1923 under the name of John F. Sipe . The story told on various websites is that, in
255-605: The tires had poor wet grip anyway, owing to their limited contact patch . It was his son, Harry E. Sipe, who popularised the use of sipes in the US for the new low-pressure balloon tires around 1939. The process was not applied to vehicle tires on a large scale until the 1950s, when superior tread compounds were developed that could stand up to the siping process. On roads covered with snow, ice, mud, and water, sipes usually increase traction . A US patent to Goodyear also claimed sipes improve tire traction, and tend to close completely in
272-413: The tread during manufacturing. Sipes may also be cut into the tread at a later date, called "microsiping". Bandag developed a machine for microsiping which places a curved knife blade at a slight angle on a rotating drum. The drum is placed so when it is pressed against the tread the tire is pressed into an exaggerated hollow, as if driving down a rail. The drum is lubricated and rotated and the knife makes
289-431: The weight to a higher spindle marking or increased by moving it to a lower marking. Other examples include: Traction force Traction , traction force or tractive force is a force used to generate motion between a body and a tangential surface, through the use of either dry friction or shear force . It has important applications in vehicles , as in tractive effort . Traction can also refer to
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