A belt is a loop of flexible material used to link two or more rotating shafts mechanically, most often parallel. Belts may be used as a source of motion, to transmit power efficiently or to track relative movement. Belts are looped over pulleys and may have a twist between the pulleys, and the shafts need not be parallel.
105-408: In a two pulley system, the belt can either drive the pulleys normally in one direction (the same if on parallel shafts), or the belt may be crossed, so that the direction of the driven shaft is reversed (the opposite direction to the driver if on parallel shafts). The belt drive can also be used to change the speed of rotation, either up or down, by using different sized pulleys. As a source of motion,
210-554: A conveyor belt is one application where the belt is adapted to carry a load continuously between two points. The mechanical belt drive, using a pulley machine, was first mentioned in the text of the Dictionary of Local Expressions by the Han Dynasty philosopher, poet, and politician Yang Xiong (53–18 BC) in 15 BC, used for a quilling machine that wound silk fibres onto bobbins for weavers' shuttles. The belt drive
315-525: A positive transfer belt and can track relative movement. These belts have teeth that fit into a matching toothed pulley. When correctly tensioned, they have no slippage, run at constant speed, and are often used to transfer direct motion for indexing or timing purposes (hence their name). They are often used instead of chains or gears, so there is less noise and a lubrication bath is not necessary. Camshafts of automobiles, miniature timing systems, and stepper motors often utilize these belts. Timing belts need
420-540: A water wheel , turbine, windmill, animal power or a steam engine . Power was distributed from the shaft to the machinery by a system of belts , pulleys and gears known as millwork . A typical line shaft would be suspended from the ceiling of one area and would run the length of that area. One pulley on the shaft would receive the power from a parent line shaft elsewhere in the building. The other pulleys would supply power to pulleys on each individual machine or to subsequent line shafts. In manufacturing where there were
525-400: A 'P' (sometimes omitted) and a single letter identifying the pitch between grooves. The 'PK' section with a pitch of 3.56 mm is commonly used for automotive applications. A further advantage of the polygroove belt that makes them popular is that they can run over pulleys on the ungrooved back of the belt. Though this is sometimes done with V-belts with a single idler pulley for tensioning,
630-456: A 180° contact angle. Smaller contact angles mean less area for the belt to obtain traction, and thus the belt carries less power. Belt drives depend on friction to operate, but excessive friction wastes energy and rapidly wears the belt. Factors that affect belt friction include belt tension, contact angle, and the materials used to make the belt and pulleys. Power transmission is a function of belt tension. However, also increasing with tension
735-734: A 2,250-newton-per-millimetre (12,800 lb f /in), 3,400-metre-long (3,700 yd) underground belt installed at Baodian Coal Mine, part of in Yanzhou Coal Mining Company , China , was reported to provide energy savings of over 15%. Whilst Shenhua Group , has installed several aramid conveyor belts, including a 4,400-newton-per-millimetre (25,000 lb f /in) belt with a length of 11,600 m (7.2 miles). Today there are different types of conveyor belts that have been created for conveying different kinds of material available in PVC and rubber materials. Material flowing over
840-404: A 31-kilometre-long (19 mi) conveyor feeding a 20-kilometre-long (12 mi) conveyor. Cable belt conveyors are a variation on the more conventional idler belt system. Instead of running on top of idlers, cable belt conveyors are supported by two endless steel cables (steel wire rope) which are in turn supported by idler pulley wheels. This system feeds bauxite through the difficult terrain of
945-473: A Louisiana-based company, registered the first patent for all plastic, modular belting. The belt consists of one or more layers of material. It is common for belts to have three layers: a top cover, a carcass and a bottom cover. The purpose of the carcass is to provide linear strength and shape. The carcass is often a woven or metal fabric having a warp & weft . The warp refers to longitudinal cords whose characteristics of resistance and elasticity define
1050-416: A belt and a pulley is expressed as the product of difference of tension and belt velocity: P = ( T 1 − T 2 ) v , {\displaystyle P=(T_{1}-T_{2})v,} where T 1 {\displaystyle T_{1}} and T 2 {\displaystyle T_{2}} are tensions in the tight side and slack side of
1155-483: A belt-drive transmission system are numerous, and this has led to many variations on the theme. Belt drives run smoothly and with little noise, and provide shock absorption for motors, loads, and bearings when the force and power needed changes. A drawback to belt drives is that they transmit less power than gears or chain drives. However, improvements in belt engineering allow use of belts in systems that formerly only allowed chain drives or gears. Power transmitted between
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#17328023920021260-595: A cement factory at Chhatak Bangladesh . It is about 17 km (11 miles) long and conveys limestone and shale at 960 t/h (1,060 short tons per hour), from the quarry in India to the cement factory (7 km or 4.3 miles long in India and 10 km or 6.2 miles long in Bangladesh). The conveyor was engineered by AUMUND France and Larsen & Toubro. The conveyor is actuated by three synchronized drive units for
1365-416: A central steam engine and distributed power through line shafts to all the leased rooms. Power buildings continued to be built in the early days of electrification, still using line shafts but driven by an electric motor. As some factories grew too large and complex to be powered by a single steam engine, a system of "sub divided" power came into use. This was also important when a wide range of speed control
1470-415: A circular section like a pipe. Like a troughed belt conveyor, a pipe conveyor also uses idler rollers. However, in this case, the idler frame completely surrounds the conveyor belt helping it to retain the pipe section while pushing it forward. In the case of travel paths requiring high angles and snake-like curvatures, a sandwich belt is used. The sandwich belt design enables materials carried to travel along
1575-406: A closed loop of carrying medium—the conveyor belt—that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley is called the idler pulley. There are two main industrial classes of belt conveyors; Those in general material handling such as those moving boxes along inside
1680-565: A conveyor is about to turn on. In the United States, the Occupational Safety and Health Administration has issued regulations for conveyor safety, as OSHA 1926.555. Some other systems used to safeguard the conveyor are belt sway switches, speed switches, belt rip switch, and emergency stops . The belt sway switch will stop the conveyor if the belt starts losing its alignment along the structure. The speed switch will stop
1785-480: A corner. These conveyor systems are commonly used in postal sorting offices and airport baggage handling systems . Belt conveyors are generally fairly similar in construction consisting of a metal frame with rollers at either end of a flat metal bed. Rubber conveyor belts are commonly used to convey items with irregular bottom surfaces, small items that would fall in between rollers (e.g. a sushi conveyor bar ), or bags of product that would sag between rollers. The belt
1890-468: A crossed belt drive the sum rather than the difference of radii is the basis for computation for length. So the wider the small drive increases, the belt length is higher. Conveyor belt A conveyor belt is the carrying medium of a belt conveyor system (often shortened to belt conveyor). A belt conveyor system is one of many types of conveyor systems . A belt conveyor system consists of two or more pulleys (sometimes referred to as drums), with
1995-453: A different kind. They consist of a very thin belt (0.5–15 millimeters or 100–4000 micrometres) strip of plastic and occasionally rubber. They are generally intended for low-power (less than 10 watts), high-speed uses, allowing high efficiency (up to 98%) and long life. These are seen in business machines, printers, tape recorders, and other light-duty operations. Timing belts (also known as toothed , notch , cog , or synchronous belts) are
2100-549: A distance of a few miles or kilometers. They used widely spaced, large diameter wheels and had much lower friction loss than line shafts, and had one-tenth the initial cost. To supply small scale power that was impractical for individual steam engines, central station hydraulic systems were developed. Hydraulic power was used to operate cranes and other machinery in British ports and elsewhere in Europe. The largest hydraulic system
2205-505: A factory and bulk material handling such as those used to transport large volumes of resources and agricultural materials, such as grain , salt , coal , ore , sand , overburden and more. Conveyors are durable and reliable components used in automated distribution and warehousing, as well as manufacturing and production facilities. In combination with computer-controlled pallet handling equipment this allows for more efficient retail , wholesale , and manufacturing distribution . It
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#17328023920022310-455: A half-twist before joining the ends (forming a Möbius strip ), so that wear can be evenly distributed on both sides of the belt. Belts ends are joined by lacing the ends together with leather thonging (the oldest of the methods), steel comb fasteners and/or lacing, or by gluing or welding (in the case of polyurethane or polyester). Flat belts were traditionally jointed, and still usually are, but they can also be made with endless construction. In
2415-656: A large number of machines performing the same tasks, the design of the system was fairly regular and repeated. In other applications such as machine and wood shops where there was a variety of machines with different orientations and power requirements, the system would appear erratic and inconsistent with many different shafting directions and pulley sizes. Shafts were usually horizontal and overhead but occasionally were vertical and could be underground. Shafts were usually rigid steel, made up of several parts bolted together at flanges. The shafts were suspended by hangers with bearings at certain intervals of length. The distance depended on
2520-403: A means of shutting the machine off when not in use. Usually at the last belt feeding power to a machine, a pair of stepped pulleys could be used to give a variety of speed settings for the machine. Occasionally gears were used between shafts to change speed rather than belts and different-sized pulleys, but this seems to have been relatively uncommon. Early versions of line shafts date back into
2625-444: A mine to a refinery that converts the coal to diesel fuel. The third longest trough belt conveyor in the world is the 20-kilometre-long (12 mi) Curragh conveyor near Westfarmers, QLD, Australia. Conveyor Dynamics, Inc. supplied the basic engineering, control system and commissioning. Detail engineering and Construction was completed by Laing O'Rourke. The longest single-belt international conveyor runs from Meghalaya in India to
2730-512: A multi-V, running on matching multi-groove sheaves. This is known as a multiple-V-belt drive (or sometimes a "classical V-belt drive"). V-belts may be homogeneously rubber or polymer throughout, or there may be fibers embedded in the rubber or polymer for strength and reinforcement. The fibers may be of textile materials such as cotton, polyamide (such as nylon ) or polyester or, for greatest strength, of steel or aramid (such as Technora , Twaron or Kevlar ). When an endless belt does not fit
2835-409: A patent in 1925, and Allis-Chalmers began marketing the drive under the "Texrope" brand; the patent was granted in 1928 ( U.S. patent 1,662,511 ). The "Texrope" brand still exists, although it has changed ownership and no longer refers to multiple-V-belt drive alone. A multi-groove, V-ribbed, or polygroove belt is made up of usually between 3 and 24 V-shaped sections alongside each other. This gives
2940-399: A path of high inclines up to 90-degree angles, enabling a vertical path as opposed to a horizontal one. This transport option is also powered by idlers. Other important components of the belt conveying system apart from the pulleys and idler rollers include the drive arrangement of reducer gear boxes, drive motors, and associated couplings. scrapers to clean the belt, chutes for controlling
3045-555: A polygroove belt may be wrapped around a pulley on its back tightly enough to change its direction, or even to provide a light driving force. Any V-belt's ability to drive pulleys depends on wrapping the belt around a sufficient angle of the pulley to provide grip. Where a single-V-belt is limited to a simple convex shape, it can adequately wrap at most three or possibly four pulleys, so can drive at most three accessories. Where more must be driven, such as for modern cars with power steering and air conditioning, multiple belts are required. As
3150-433: A shop or factory of any description without encountering a mass of belts which seem at first to monopolize every nook in the building and leave little or no room for anything else." To overcome the distance and friction limitations of line shafts, wire rope systems were developed in the late 19th century. Wire rope operated at higher velocities than line shafts and were a practical means of transmitting mechanical power for
3255-437: A staple, a metallic connector (in the case of hollow plastic), gluing or welding (in the case of polyurethane ). Early sewing machines utilized a leather belt, joined either by a metal staple or glued, to great effect. Spring belts are similar to rope or round belts but consist of a long steel helical spring. They are commonly found on toy or small model engines, typically steam engines driving other toys or models or providing
Belt (mechanical) - Misplaced Pages Continue
3360-422: A thinner belt for the same drive surface, thus it is more flexible, although often wider. The added flexibility offers an improved efficiency, as less energy is wasted in the internal friction of continually bending the belt. In practice this gain of efficiency causes a reduced heating effect on the belt, and a cooler-running belt lasts longer in service. Belts are commercially available in several sizes, with usually
3465-577: A total power of about 1.8 MW supplied by ABB (two drives at the head end in Bangladesh and one drive at the tail end in India). The conveyor belt was manufactured in 300-metre (980-foot) lengths on the Indian side and 300-metre (980-foot) lengths on the Bangladesh side. The idlers, or rollers, of the system are unique{{ }} in that they are designed to accommodate both horizontal and vertical curves along
3570-409: A transmission between the crankshaft and other parts of a vehicle. The main advantage over rubber or other elastic belts is that they last much longer under poorly controlled operating conditions. The distance between the pulleys is also less critical. Their main disadvantage is that slippage is more likely due to the lower coefficient of friction. The ends of a spring belt can be joined either by bending
3675-437: A troughed belt conveyor is used. The trough of the belt ensures that the flowable material is contained within the edges of the belt. The trough is achieved by keeping the idler rollers in an angle to the horizontal at the sides of the idler frame. A pipe conveyor is used for material travel paths that require sharper bends and inclines up to 35 degrees. A pipe conveyor features the edges of the belt being rolled together to form
3780-416: Is Factors of power adjustment include speed ratio; shaft distance (long or short); type of drive unit (electric motor, internal combustion engine); service environment (oily, wet, dusty); driven unit loads (jerky, shock, reversed); and pulley-belt arrangement (open, crossed, turned). These are found in engineering handbooks and manufacturer's literature. When corrected, the power is compared to rated powers of
3885-507: Is a power-driven rotating shaft for power transmission that was used extensively from the Industrial Revolution until the early 20th century. Prior to the widespread use of electric motors small enough to be connected directly to each piece of machinery, line shafting was used to distribute power from a large central power source to machinery throughout a workshop or an industrial complex. The central power source could be
3990-417: Is a twist between each pulley so that the pulleys only contact the same belt surface. Nonparallel shafts can be connected if the belt's center line is aligned with the center plane of the pulley. Industrial belts are usually reinforced rubber but sometimes leather types. Non-leather, non-reinforced belts can only be used in light applications. The pitch line is the line between the inner and outer surfaces that
4095-440: Is an essential component of the invention of the spinning wheel . The belt drive was not only used in textile technologies, it was also applied to hydraulic-powered bellows dated from the 1st century AD. Belts are the cheapest utility for power transmission between shafts that may not be axially aligned. Power transmission is achieved by purposely designed belts and pulleys. The variety of power transmission needs that can be met by
4200-611: Is considered a labor-saving system that allows large volumes to move rapidly through a process, allowing companies to ship or receive higher volumes with smaller storage space and with labor expense . Belt conveyors are the most commonly used powered conveyors because they are the most versatile and the least expensive. Products are conveyed directly on the belt so both regular and irregular shaped objects, large or small, light and heavy, can be transported successfully. Belt conveyors are also manufactured with curved sections that use tapered rollers and curved belting to convey products around
4305-526: Is crucial to compensate for wear and stretch. Flat belts were widely used in the 19th and early 20th centuries in line shafting to transmit power in factories. They were also used in countless farming , mining , and logging applications, such as bucksaws , sawmills , threshers , silo blowers , conveyors for filling corn cribs or haylofts , balers , water pumps (for wells , mines, or swampy farm fields), and electrical generators . Flat belts are still used today, although not nearly as much as in
Belt (mechanical) - Misplaced Pages Continue
4410-400: Is executed, retensioning (via pulley centerline adjustment) or dressing (with any of various coatings) may be successful to extend the belt's lifespan and postpone replacement. Belt dressings are typically liquids that are poured, brushed, dripped, or sprayed onto the belt surface and allowed to spread around; they are meant to recondition the belt's driving surfaces and increase friction between
4515-496: Is extremely rare today, dating mostly from the 18th century. Flat belts on flat pulleys or drums were the most common method during the 19th and early 20th centuries. The belts were generally tanned leather or cotton duck impregnated with rubber. Leather belts were fastened in loops with rawhide or wire lacing, lap joints and glue, or one of several types of steel fasteners. Cotton duck belts usually used metal fasteners or were melted together with heat. The leather belts were run with
4620-600: Is in the developing stages and will prove to be an efficient innovation. The longest belt conveyor system in the world is in Western Sahara . It was built in 1972 by Friedrich Krupp GmbH (now thyssenkrupp) and is 98 km (61 miles) long, from the phosphate mines of Bu Craa to the coast south of El-Aaiun . The longest conveyor system in an airport is the Dubai International Airport baggage handling system at 63 km (39 miles). It
4725-420: Is looped around each of the rollers and when one of the rollers is powered (by an electrical motor ) the belting slides across the solid metal frame bed, moving the product. In heavy use applications, the beds in which the belting is pulled over are replaced with rollers. The rollers allow weight to be conveyed as they reduce the amount of friction generated from the heavier loading on the belting. The exception to
4830-424: Is more efficient at transferring power (up to 98%). The advantages of timing belts include clean operation, energy efficiency , low maintenance, low noise, non slip performance, versatile load and speed capabilities. Disadvantages include a relatively high purchase cost, the need for specially fabricated toothed pulleys, less protection from overloading, jamming, and vibration due to their continuous tension cords,
4935-401: Is neither subject to tension (like the outer surface) nor compression (like the inner). It is midway through the surfaces in film and flat belts and dependent on cross-sectional shape and size in timing and V-belts. Standard reference pitch diameter can be estimated by taking average of gear teeth tips diameter and gear teeth base diameter. The angular speed is inversely proportional to size, so
5040-414: Is often more economical to use two or more juxtaposed V-belts, rather than one larger belt. In large speed ratios or small central distances, the angle of contact between the belt and pulley may be less than 180°. If this is the case, the drive power must be further increased, according to manufacturer's tables, and the selection process repeated. This is because power capacities are based on the standard of
5145-442: Is stress (load) on the belt and bearings. The ideal belt is that of the lowest tension that does not slip in high loads. Belt tensions should also be adjusted to belt type, size, speed, and pulley diameters. Belt tension is determined by measuring the force to deflect the belt a given distance per inch (or mm) of pulley. Timing belts need only adequate tension to keep the belt in contact with the pulley. Fatigue, more so than abrasion,
5250-399: Is the culprit for most belt problems. This wear is caused by stress from rolling around the pulleys. High belt tension; excessive slippage; adverse environmental conditions; and belt overloads caused by shock, vibration, or belt slapping all contribute to belt fatigue. Vibration signatures are widely used for studying belt drive malfunctions. Some of the common malfunctions or faults include
5355-477: Is typically no longer done with belts at all. For example, factory machines now tend to have individual electric motors. Because flat belts tend to climb towards the higher side of the pulley, pulleys were made with a slightly convex or "crowned" surface (rather than flat) to allow the belt to self-center as it runs. Flat belts also tend to slip on the pulley face when heavy loads are applied, and many proprietary belt dressings were available that could be applied to
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#17328023920025460-474: The Rhodesian Bush War (1964–1979): To protect riders of cars and busses from land mines, layers of leather belt drives were placed on the floors of vehicles in danger zones. Today most belt drives are made of rubber or synthetic polymers. Grip of leather belts is often better if they are assembled with the hair side (outer side) of the leather against the pulley, although some belts are instead given
5565-410: The check-out counter to move shopping items, and may use checkout dividers in this process. Ski areas also use conveyor belts to transport skiers up the hill. Industrial and manufacturing applications for belt conveyors include package handling, trough belt conveyors, trash handling, bag handling, coding conveyors, and more. Integration of Human-Machine Interface(HMI) to operate the conveyor system
5670-544: The "flying rope", and in the late 19th century, this was considered quite efficient. Round belts are a circular cross section belt designed to run in a pulley with a 60 degree V-groove. Round grooves are only suitable for idler pulleys that guide the belt, or when (soft) O-ring type belts are used. The V-groove transmits torque through a wedging action, thus increasing friction. Nevertheless, round belts are for use in relatively low torque situations only and may be purchased in various lengths or cut to length and joined, either by
5775-456: The 18th century, but they were in widespread use in the late 19th century with industrialization. Line shafts were widely used in manufacturing, woodworking shops, machine shops, saw mills and grist mills . In 1828 in Lowell, Massachusetts, Paul Moody substituted leather belting for metal gearing to transfer power from the main shaft running from a water wheel. This innovation quickly spread in
5880-429: The 1980s; since then many have been replaced with sectional electric drives. Economical variable speed control using electric motors was made possible by silicon controlled rectifiers (SCRs) to produce direct current and variable frequency drives using inverters to change DC back to AC at the frequency required for the desired speed. Most systems were out of service by the mid-20th century and relatively few remain in
5985-484: The 19th century. In 1868, an English shipwright Joseph Thomas Parlour from Pimlico patented a grain elevator with a conveyor belt while Illinoisan Charles Denton of Ames Plow Co. patented a reaper with a belt "conveyer". By the 1880s conveyor belts were used in American elevators, sugarcane mills and sawmills , as well as British maltings . In 1892, Thomas Robins began a series of inventions which led to
6090-403: The 21st century, even fewer in their original location and configuration. Compared to individual electric motor or unit drive, line shafts have the following disadvantages: Firms switching to electric power showed significantly less employee sick time, and, using the same equipment, showed significant increases in production. Writing in 1909, James Hobart said that "We can scarcely step into
6195-485: The B. F. Goodrich Company patented a Möbius strip conveyor belt, that it went on to produce as the "Turnover Conveyor Belt System". Incorporating a half-twist, it had the advantage over conventional belts of a longer life because it could expose all of its surface area to wear and tear. Such Möbius strip belts are no longer manufactured because untwisted modern belts can be made more durable by constructing them from several layers of different materials. In 1970, Intralox ,
6300-689: The Darling Ranges to the Worsley Alumina refinery. The second longest single trough belt conveyor is the 26.8-kilometre-long (16.7 mi) Impumelelo conveyor near Secunda, South Africa. It was designed by Conveyor Dynamics, Inc. based in Bellingham, Washington, USA and constructed by ELB Engineering based in Johannesburg South Africa. The conveyor transports 2,400 t/h (2,600 short tons per hour) coal from
6405-875: The French society REI created in New Caledonia the longest straight-belt conveyor in the world in that moment, at a length of 13.8 km (8.6 miles). Hyacynthe Marcel Bocchetti was the concept designer. . The longest conveyor belt is that of the Bou Craa phosphate mine in Western Sahara (1973, 98 km in 11 sections). The longest single-span conveyor belt is at the Boddington bauxite mine in Western Australia (31 km). In 1957,
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#17328023920026510-450: The U.S. Flat-belt drive systems became popular in the UK from the 1870s, with the firms of J & E Wood and W & J Galloway & Sons prominent in their introduction. Both of these firms manufactured stationary steam engines and the continuing demand for more power and reliability could be met not merely by improved engine technology but also improved methods of transferring power from
6615-596: The V-belt an effective solution, needing less width and tension than flat belts. V-belts trump flat belts with their small center distances and high reduction ratios. The preferred center distance is larger than the largest pulley diameter, but less than three times the sum of both pulleys. Optimal speed range is 1,000–7,000 ft/min (300–2,130 m/min). V-belts need larger pulleys for their thicker cross-section than flat belts. For high-power requirements, two or more V-belts can be joined side-by-side in an arrangement called
6720-467: The arrangement of power drives such that if one part were to fail then it would not cause loss of power to all sections of a factory or mill. These systems were in turn superseded in popularity by rope drive methods. Near the end of the 19th century some factories had a mile or more of line shafts in a single building. In order to provide power for small shops and light industry, specially constructed "power buildings" were constructed. Power buildings used
6825-440: The bearings, and long service life. They are generally endless, and their general cross-section shape is roughly trapezoidal (hence the name "V"). The "V" shape of the belt tracks in a mating groove in the pulley (or sheave), with the result that the belt cannot slip off. The belt also tends to wedge into the groove as the load increases—the greater the load, the greater the wedging action—improving torque transmission and making
6930-405: The belt and the pulleys. Some belt dressings are dark and sticky, resembling tar or syrup ; some are thin and clear, resembling mineral spirits . Some are sold to the public in aerosol cans at auto parts stores; others are sold in drums only to industrial users. To fully specify a belt, the material, length, and cross-section size and shape are required. Timing belts, in addition, require that
7035-567: The belt if the switch is not registering that the belt is running at the required speed. The belt rip switch will stop the belt when there is a cut, or a flap indicating that the belt is in danger of further damage. An emergency stop may be located on the conveyor control box in case of trip chord malfunctions. Worn rubber or elastomer belts can be reused in many ways. Applications for the material include toolbox liners, anti-fatigue floor mats, dock bumpers, landscale edging, livestock fencing, and water diversion. Line shaft A line shaft
7140-439: The belt is in contact, a power range up to 600 kW, a high speed ratio, serpentine drives (possibility to drive off the back of the belt), long life, stability and homogeneity of the drive tension, and reduced vibration. The ribbed belt may be fitted on various applications: compressors, fitness bikes, agricultural machinery, food mixers, washing machines, lawn mowers, etc. Though often grouped with flat belts, they are actually
7245-564: The belt material, and mentioned that the V angle was not yet well standardized. The endless rubber V-belt was developed in 1917 by Charles C. Gates of the Gates Rubber Company . Multiple-V-belt drive was first arranged a few years later by Walter Geist of the Allis-Chalmers corporation, who was inspired to replace the single rope of multi-groove-sheave rope drives with multiple V-belts running parallel. Geist filed for
7350-463: The belt may be weighed in transit using a beltweigher . Belts with regularly spaced partitions, known as elevator belts , are used for transporting loose materials up steep inclines. Belt Conveyors are used in self-unloading bulk freighters and in live bottom trucks. Belt conveyor technology is also used in conveyor transport such as moving sidewalks or escalators , as well as on many manufacturing assembly lines . Stores often have conveyor belts at
7455-435: The belt respectively. They are related as T 1 T 2 = e μ α , {\displaystyle {\frac {T_{1}}{T_{2}}}=e^{\mu \alpha },} where μ {\displaystyle \mu } is the coefficient of friction, and α {\displaystyle \alpha } is the angle (in radians) subtended by contact surface at
7560-618: The belt. Steel conveyor belts are used when high strength class is required. For example, the highest strength class conveyor belt installed is made of steel cords. This conveyor belt has a strength class of 10,000 N/mm (57,000 lb f /in) and it operates at Chuquicamata mine, in Chile . Polyester, nylon and cotton are popular with low strength classes. Aramid is used in the range 630–3,500 N/mm (3,600–20,000 lb f /in). The advantages of using aramid are energy savings, enhanced lifetimes and improved productivity. As an example,
7665-551: The belts to increase friction, and so power transmission. Flat belts were traditionally made of leather or fabric. Early flour mills in Ukraine had leather belt drives. After World War I, there was such a shortage of shoe leather that people cut up the belt drives to make shoes. Selling shoes was more profitable than selling flour for a time. Flour milling soon came to a standstill and bread prices rose, contributing to famine conditions. Leather drive belts were put to another use during
7770-416: The centre of the pulley. Belt drives are simple, inexpensive, and do not require axially aligned shafts. They help protect machinery from overload and jam, and damp and isolate noise and vibration. Load fluctuations are shock-absorbed (cushioned). They need no lubrication and minimal maintenance. They have high efficiency (90–98%, usually 95%), high tolerance for misalignment, and are of relatively low cost if
7875-402: The compression side of the loop. Belts used for rolling roads for wind tunnels can be capable of 250 km/h (160 mph). The open belt drive has parallel shafts rotating in the same direction, whereas the cross-belt drive also bears parallel shafts but rotate in opposite direction. The former is far more common, and the latter not appropriate for timing and standard V-belts unless there
7980-429: The development of a conveyor belt used for carrying coal, ores and other products. In 1901, Sandvik invented and started the production of steel conveyor belts. In 1905, Richard Sutcliffe invented the first conveyor belts for use in coal mines which revolutionized the mining industry. In 1913, Henry Ford introduced conveyor-belt assembly lines at Ford Motor Company 's Highland Park, Michigan factory. In 1972,
8085-456: The discharge direction, skirts for containing the discharge on the receiving belt, take up assembly for "tensioning" the belt, safety switches for personnel safety and technological structures like stringer, short post, drive frames, pulley frames make up the balance items to complete the belt conveying system. In certain applications, belt conveyors can also be used for static accumulation or cartons. Primitive conveyor belts have been in use since
8190-417: The effects of belt tension , speed, sheave eccentricity and misalignment conditions. The effect of sheave Eccentricity on vibration signatures of the belt drive is quite significant. Although, vibration magnitude is not necessarily increased by this it will create strong amplitude modulation. When the top section of a belt is in resonance , the vibrations of the machine is increased. However, an increase in
8295-468: The elongation of the belt's outer fibers as the belt wraps around the pulleys. Small pulleys increase this elongation, greatly reducing belt life. Minimal pulley diameters are often listed with each cross-section and speed, or listed separately by belt cross-section. After the cheapest diameters and belt section are chosen, the belt length is computed. If endless belts are used, the desired shaft spacing may need adjusting to accommodate standard-length belts. It
8400-515: The engines to the looms and similar machinery which they were intended to service. The use of flat belts was already common in the US but rare in Britain until this time. The advantages included less noise and less wasted energy in the friction losses inherent in the previously common drive shafts and their associated gearing. Also, maintenance was simpler and cheaper, and it was a more convenient method for
8505-415: The hair side against the pulleys for best traction. The belts needed periodic cleaning and conditioning to keep them in good condition. Belts were often twisted 180 degrees per leg and reversed on the receiving pulley to cause the second shaft to rotate in the opposite direction. Pulleys were constructed of wood, iron, steel or a combination thereof. Varying sizes of pulleys were used in conjunction to change
8610-400: The lack of clutch action (only possible with friction-drive belts), and the fixed lengths, which do not allow length adjustment (unlike link V-belts or chains). Belts normally transmit power on the tension side of the loop. However, designs for continuously variable transmissions exist that use belts that are a series of solid metal blocks, linked together as in a chain, transmitting power on
8715-533: The larger the one wheel, the less angular velocity, and vice versa. Actual pulley speeds tend to be 0.5–1% less than generally calculated because of belt slip and stretch. In timing belts, the inverse ratio teeth of the belt contributes to the exact measurement. The speed of the belt is: Standards include: Belt drives are built under the following required conditions: speeds of and power transmitted between drive and driven unit; suitable distance between shafts; and appropriate operating conditions. The equation for power
8820-407: The last turn of the helix at each end by 90 degrees to form hooks, or by reducing the diameter of the last few turns at one end so that it "screws" into the other end. V belts (also style V-belts, vee belts, or, less commonly, wedge rope) solved the slippage and alignment problem. It is now the basic belt for power transmission. They provide the best combination of traction, speed of movement, load of
8925-452: The least tension of all belts and are among the most efficient. They can bear up to 200 hp (150 kW) at speeds of 16,000 ft/min (4,900 m/min). Timing belts with a helical offset tooth design are available. The helical offset tooth design forms a chevron pattern and causes the teeth to engage progressively. The chevron pattern design is self-aligning and does not make the noise that some timing belts make at certain speeds, and
9030-469: The length of either side, the length of the belt increases, in a similar manner to the Pythagorean theorem. One important concept to remember is that as D 1 {\displaystyle D_{1}} gets closer to D 2 {\displaystyle D_{2}} there is less of a distance (and therefore less addition of length) as it approaches zero. On the other hand, in
9135-681: The line shafts. Eventually Baldwin converted to electric drive, with a substantial saving in labor and building space. With factory electrification in the early 1900s, many line shafts began converting to electric drive. In early factory electrification only large motors were available, so new factories installed a large motor to drive line shafting and millwork. After 1900 smaller industrial motors became available and most new installations used individual electric drives. Steam turbine powered line shafts were commonly used to drive paper machines for speed control reasons until economical methods for precision electric motor speed control became available in
9240-526: The line-shaft era. The flat belt is a simple system of power transmission that was well suited for its day. It can deliver high power at high speeds (373 kW at 51 m/s; 115 mph), in cases of wide belts and large pulleys. Wide-belt-large-pulley drives are bulky, consuming much space while requiring high tension, leading to high loads, and are poorly suited to close-centers applications. V-belts have mainly replaced flat belts for short-distance power transmission; and longer-distance power transmission
9345-417: The machine vibration is not significant when only the bottom section of the belt is in resonance. The vibration spectrum has the tendency to move to higher frequencies as the tension force of the belt is increased. Belt slippage can be addressed in several ways. Belt replacement is an obvious solution, and eventually the mandatory one (because no belt lasts forever). Often, though, before the replacement option
9450-495: The mid 19th century, British millwrights discovered that multi-grooved pulleys connected by ropes outperformed flat pulleys connected by leather belts. Wire ropes were occasionally used, but cotton , hemp , manila hemp and flax rope saw the widest use. Typically, the rope connecting two pulleys with multiple V-grooves was spliced into a single loop that traveled along a helical path before being returned to its starting position by an idler pulley that also served to maintain
9555-508: The need to provide movable tensioning adjustments. The entire belt may be tensioned by a single idler pulley. The nomenclature used for belt sizes varies by region and trade. An automotive belt with the number "740K6" or "6K740" indicates a belt 74 inches (190 cm) in length, 6 ribs wide, with a rib pitch of 9 ⁄ 64 of an inch (3.6 mm) (a standard thickness for a K series automotive belt would be 4.5mm). A metric equivalent would be usually indicated by "6PK1880" whereby 6 refers to
9660-610: The need, jointed and link V-belts may be employed. Most models offer the same power and speed ratings as equivalently-sized endless belts and do not require special pulleys to operate. A link v-belt is a number of polyurethane/polyester composite links held together, either by themselves, such as Fenner Drives' PowerTwist, or Nu-T-Link (with metal studs). These provide easy installation and superior environmental resistance compared to rubber belts and are length-adjustable by disassembling and removing links when needed. Trade journal coverage of V-belts in automobiles from 1916 mentioned leather as
9765-404: The number of ribs, PK refers to the metric PK thickness and pitch standard, and 1880 is the length of the belt in millimeters. A ribbed belt is a power transmission belt featuring lengthwise grooves. It operates from contact between the ribs of the belt and the grooves in the pulley. Its single-piece structure is reported to offer an even distribution of tension across the width of the pulley where
9870-401: The polygroove belt can be bent into concave paths by external idlers, it can wrap any number of driven pulleys, limited only by the power capacity of the belt. This ability to bend the belt at the designer's whim allows it to take a complex or " serpentine " path. This can assist the design of a compact engine layout, where the accessories are mounted more closely to the engine block and without
9975-470: The running properties of the belt. The weft represents the whole set of transversal cables allowing to the belt specific resistance against cuts, tears and impacts and at the same time high flexibility. The most common carcass materials are steel , polyester , nylon , cotton and aramid (class of heat-resistant and strong synthetic fibers, with Twaron or Kevlar as brand names). The covers are usually various rubber or plastic compounds specified by use of
10080-525: The shafts are far apart. Clutch action can be achieved by shifting the belt to a free turning pulley or by releasing belt tension. Different speeds can be obtained by stepped or tapered pulleys. The angular-velocity ratio may not be exactly constant or equal to that of the pulley diameters, due to slip and stretch. However, this problem can be largely solved by the use of toothed belts. Working temperatures range from −35 to 85 °C (−31 to 185 °F). Adjustment of centre distance or addition of an idler pulley
10185-445: The size of the teeth be given. The length of the belt is the sum of the central length of the system on both sides, half the circumference of both pulleys, and the square of the sum (if crossed) or the difference (if open) of the radii. Thus, when dividing by the central distance, it can be visualized as the central distance times the height that gives the same squared value of the radius difference on, of course, both sides. When adding to
10290-430: The speed of rotation. For example, a 40" pulley at 100 rpm would turn a 20" pulley at 200 rpm. Pulleys solidly attached ("fast") to the shaft could be combined with adjacent pulleys that turned freely ("loose") on the shaft (idlers). In this configuration the belt could be maneuvered onto the idler to stop power transmission or onto the solid pulley to convey the power. This arrangement was often used near machines to provide
10395-461: The standard belt conveyor construction is the sandwich belt conveyor. The sandwich belt conveyor uses two conveyor belts, instead of one. These two conventional conveyor belts are positioned face to face, to firmly contain the items being carried in a "sandwich-like" hold. Belt conveyors can be used to transport products in a straight line or through changes in elevation or direction. For conveying bulk materials, over gentle slopes or gentle curvatures,
10500-459: The standard belt cross-sections at particular belt speeds to find a number of arrays that perform best. Now the pulley diameters are chosen. It is generally either large diameters or large cross-section that are chosen, since, as stated earlier, larger belts transmit this same power at low belt speeds as smaller belts do at high speeds. To keep the driving part at its smallest, minimal-diameter pulleys are desired. Minimum pulley diameters are limited by
10605-555: The tension on the rope. Sometimes, a single rope was used to transfer power from one multiple-groove drive pulley to several single- or multiple-groove driven pulleys in this way. In general, as with flat belts, rope drives were used for connections from stationary engines to the jack shafts and line shafts of mills, and sometimes from line shafts to driven machinery. Unlike leather belts, however, rope drives were sometimes used to transmit power over relatively long distances. Over long distances, intermediate sheaves were used to support
10710-470: The terrain. Dedicated vehicles were designed for the maintenance of the conveyor, which is always at a minimum height of 5 metres (16 ft) above the ground to avoid being flooded during monsoon periods. Conveyors used in industrial settings include tripping mechanisms such as trip cords along the length of the conveyor. This allows for workers to immediately shut down the conveyor when a problem arises. Warning alarms are included to notify employees that
10815-457: The weight of the shaft and the number of pulleys. The shafts had to be kept aligned or the stress would overheat the bearings and could break the shaft. The bearings were usually friction type and had to be kept lubricated. Pulley lubricator employees were required in order to ensure that the bearings did not freeze or malfunction. In the earliest applications power was transmitted between pulleys using loops of rope on grooved pulleys. This method
10920-407: Was installed by Siemens and commissioned in 2008, and has a combination of traditional belt conveyors and tray conveyors. Boddington Bauxite Mine in Western Australia is officially recognized as having the world's longest single flight conveyor. Single flight means the load is not transferred, it is a single continuous system for the entire length. This conveyor is a cable belt conveyor system with
11025-500: Was necessary for a sensitive operation such as wire drawing or hammering iron. Under sub divided power, steam was piped from a central boiler to smaller steam engines located where needed. However, small steam engines were much less efficient than large ones. The Baldwin Locomotive Works 63-acre site changed to sub divided power, then because of the inefficiency converted to group drive with several large steam engines driving
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