Power take-off

A power take-off or power takeoff (PTO) is any of several methods for taking power from a power source, such as a running engine, and transmitting it to an application such as an attached implement or separate machines.

Most commonly, it is a splined drive shaft installed on a tractor or truck allowing implements with mating fittings to be powered directly by the engine.

Semi-permanently mounted power take-offs can also be found on industrial and marine engines. These applications typically use a drive shaft and bolted joint to transmit power to a secondary implement or accessory. In the case of a marine application, such shafts may be used to power fire pumps.

In aircraft applications, such an accessory drive may be used in conjunction with a constant speed drive. Jet aircraft have four types of PTO units: internal gearbox, external gearbox, radial drive shaft, and bleed air, which are used to power engine accessories. In some cases, aircraft power take-off systems also provide for putting power into the engine during engine start. See also Coffman starter [1]

Zapfwelle eines Traktors - power take-off of a tractor
A PTO at the rear end of a farm tractor
A Tractor's rear
A PTO (in the box at the bottom) in between the three-point hitch of a tractor

History

Various power transmission methods were available before power takeoffs became common, but there were applications left wanting for some of the attributes that PTOs would provide. Flat belts generally lent themselves only to applications where the engine was stationary, such as factory steam engines, portable stationary engines, or traction engines parked in front of the work. For moving vehicles such as a traction engine or early tractor towing a farm implement, the implement could receive rotary power by taking it from one of its own wheels (whose turning was imparted by the towing) and distributing it via roller chains (to a sickle bar's crank, for example), but such a transmission ceases if the vehicle stops traveling; and the workload's resistance tends to make the wheel skid rather than turn, even if cleated. The concept of a shaft drive with easily connected and disconnected couplings, and flexibility for driving at changing angles (such as when an articulated tractor-and-trailer combination turns), was a goal to pursue.

Experimental power take-offs were tried as early as 1878, and various homemade versions arose over the subsequent decades. International Harvester Company (IHC) was first to market with a PTO on a production tractor, with its model 8-16, introduced in 1918.[2] Edward A. Johnston, an IHC engineer, had been impressed by a homemade PTO that he saw in France about a decade before, improvised by a French farmer and mechanic surnamed Gougis.[2] He and his IHC colleagues incorporated the idea into the 8-16, and designed a family of implements to take advantage of the feature. IHC was not alone in the market for long, as within a year PTOs were appearing on other production tractors, such as some Case models. In 1920, IHC offered the PTO option on their 15-30 tractor, and it was the first PTO-equipped tractor to be submitted for a Nebraska tractor test. The PTO was a competitive advantage for IHC in the 1920s, and other companies eventually caught up with PTO implementation.

Inside the transmission, the exact point along the gear train where the power is taken off determines whether the PTO can be run independently of vehicle travel (ground speed). Early PTOs were often taken off the main output shaft, meaning that the vehicle had to be "in gear" in order to run the PTO. Later this was improved by so-called live PTO (LPTO) designs, which allow control of the PTO rotation independently of the tractor motion. This is an advantage when the load driven by the PTO requires the tractor motion to slow or stop running to allow the PTO driven equipment to catch up. It also allows operations where the tractor remains parked, such as silo-filling or unloading a manure spreader to a pile or lagoon rather than across a field. In 1945, Cockshutt Farm Equipment Ltd of Brantford, Ontario, Canada, introduced the Cockshutt Model 30 tractor with LPTO. Most PTOs built today are live. In modern tractors, LPTO is often controlled by push-button or selector switch. This increases safety of operators who need to get close to the PTO shaft.

Safety

TractorPTOshaftMay04
Protective plastic sheath enshrouding a PTO

The PTO and its associated shafts and universal joints are a common cause of incidents and injury in farming and industry. According to the National Safety Council, 6 percent of tractor related fatalities in 1997 in the United States involved the PTO. Incidents can occur when loose clothing is pulled into the shaft, often resulting in bone fractures, loss of limb, or death to its wearer. On April 13, 2009 former Major League Baseball star Mark Fidrych died as a result of a PTO related accident; "He appeared to have been working on the truck when his clothes became tangled in the truck's power takeoff shaft", District Attorney Joseph Early Jr. said in a statement.[3]

Some implements employ light free-spinning protective plastic guards to enshroud the PTO shaft, and are mandatory in some countries.[4][5] In the UK, Health and Safety Executive guidance is contained in a leaflet.[6]

Technical standardization

Agricultural PTOs are standardized in dimensions and speed. The ISO standard for PTOs is ISO 500, which as of the 2004 edition was split into three parts:

  1. ISO 500-1 General specifications, safety requirements, dimensions for master shield and clearance zone
  2. ISO 500-2 Narrow-track tractors, dimensions for master shield and clearance zone
  3. ISO 500-3 Main PTO dimensions and spline dimensions, location of PTO.

The original type calls for operation at 540 revolutions per minute (RPM). A shaft that rotates at 540 rpm has 6 splines on it, and a diameter of 1​38". Two newer types, supporting higher power applications, operate at 1000 RPM and differ in shaft size. The larger shaft has 20 splines (1​34" diameter), while the smaller has 21 (1​38" diameter). All three types rotate counterclockwise when viewed from the tractor (When standing behind the tractor, the shaft turns clockwise). A 10 spline type was used with some early equipment such as the 1948 Land Rover, a six spline adapter was usually supplied. It is customary for agricultural machines manufacturers to provide the nominal PTO power specification, an indication of the available instantaneous power at the shaft. Newer tractors may come equipped with 540/540E and/or 1000/1000E options that allow the tractor to power certain low-power-demand implements like hay rakes or tedders using lower engine speeds to maintain the revolutions per minute needed, using less fuel and placing less stress on the engine thereby improving efficiency and reducing costs.

The first industry standard for PTO design was adopted by ASAE (the American Society of Agricultural Engineers) in April 1927. The PTO rotational speed was specified as 536 ± 10 rpm; the direction was clockwise. The speed was later changed to 540 rpm.[7]

Use on commercial vehicles

PTO gearbox
A hydraulic PTO mounted on a truck gearbox
Unimog-1980-05
Rear crossbar with PTO hydraulic connectors and coupling on a Unimog 421

Truck transmissions have one or more locations which allow for a PTO to be mounted. The PTO must be purchased separately and care is required to match the physical interface of the transmission with a compatible PTO. PTO suppliers will usually require details of the make, model and even serial number of the transmission. Care is also needed to ensure that the physical space around the transmission allows for installation of the PTO. The PTO is engaged/disengaged using the main transmission clutch and a remote control mechanism which operates on the PTO itself. Typically an air valve is used to engage the PTO, but a mechanical linkage, electric or hydraulic mechanism are also options.

Most Unimogs come with front and/or rear PTOs and hydraulics as well as three point hitch systems.

Units will be rated according to the continuous and intermittent torque that can be applied through them and different models will offer different "PTO shaft rotation to engine RPM" ratios.

In the majority of cases, the PTO will connect directly to a hydraulic pump. This allows for transmission of mechanical force through the hydraulic fluid system to any location around the vehicle where a hydraulic motor will convert it back into rotary or linear mechanical force. Typical applications include:

  • Running a water pump on a fire engine or water truck
  • Running a truck mounted hot water extraction machine for carpet cleaning (driving vacuum blower and high-pressure solution pumps)
  • Powering a blower system used to move dry materials such as cement
  • Powering a vehicle-integrated air compressor system[8]
  • Raising a dump truck bed
  • Operating the mechanical arm on a bucket truck used by electrical maintenance personnel or Cable TV maintenance crews
  • Operating a winch on a tow truck
  • Operating the compactor on a garbage truck
  • Operating a Boom/Grapple truck
  • Operating a truck mounted tree spade and lift-mast assembly

Split shaft

A split shaft PTO is mounted to the truck's drive shaft to provide power to the PTO. Such a unit is an additional gearbox that separates the vehicle's drive shaft into two parts:

  • The gearbox-facing shaft which will transmit the power of the engine to the split shaft PTO;
  • The axle-facing shaft which transmit the propelling power to the axle.

The unit itself is designed to independently divert the engine's power to either the axle-facing shaft or the additional PTO output shaft. This is done by two independent clutches like tooth or dog clutches which can be operated at total driveline standstill, only. Since the main gearbox changes the rotation speed by selection of a gear the PTO cannot be operated during driving. The vehicle needs to be stationary for operation therefore. On 4x4 vehicles only the rear drive shaft is used by the split shaft PTO gearbox requiring the vehicles 4x4 drive scheme to be of the selectable 4WD type to keep the front axle drive shaft completely decoupled during PTO operation. It is also possible to connect something other than a hydraulic pump directly to the PTO for example, fire truck pumps.

"Sandwich" split shaft

A "Sandwich" type split shaft unit is mounted between engine and transmission and used on road maintenance vehicles, fire fighting vehicles and off-road vehicles. This unit gets the drive directly from the engine shaft and can be capable of delivering up to the complete engine power to the PTO. Usually these units come with their own lubricating system. Due to the sandwich mounting style the gearbox will be moved away from the engine requiring the driveline to accommodate the installation.

See also

References

  1. ^ NASA Technical Memorandum 101731; Monitoring Techniques for "X-29A Aircraft's High Speed Rotating Power Takeoff Shaft"; David F Voracek, Ames Research Center, Dryden Flight Research Facility, Edwards, California, December 1990 [www.nasa.gov/centers/dryden/pdf/88209main_H-1680.pdf]
  2. ^ a b Pripps & Morland 1993, pp. 37–39.
  3. ^ "Examiner: Fidrych suffocated to death". ESPN.com. 16 April 2009. Retrieved 7 January 2014.
  4. ^ Power-Take-Off (PTO) Safety (PDF), National Safety Council, May 2009, retrieved 2009-12-14
  5. ^ Privette, Charles (2002-03-01), Farm Safety & Health - PTO Safety, Department of Agricultural and Biological Engineering, Clemson University, archived from the original on March 28, 2005, retrieved 2007-04-19
  6. ^ "Power take-offs and power take-off drive shafts" (PDF). Health and Safety Executive UK. Retrieved 29 October 2018.
  7. ^ http://www.asabe.org/imis/StaticContent/4/October_2004/p_31_last_word.pdf
  8. ^ "PTO Air Compressors | Direct-Transmission™ Mounted Air Compressor". VMAC. Retrieved 2018-12-11.

Bibliography

  • Pripps, Robert N.; Morland, Andrew (photographer) (1993), Farmall Tractors: History of International McCormick-Deering Farmall Tractors, Farm Tractor Color History Series, Osceola, WI, USA: MBI, ISBN 978-0-87938-763-1.
Allis-Chalmers ED40

The Allis-Chalmers ED 40 tractor was the last model made by the UK subsidiary of the American Allis-Chalmers Corporation before the plant at Essendine, Rutland, was closed in 1985. Introduced at the Smithfield Show, London in 1960, it retained all the features that rowcrop farmers required but in a manner that made it a universal farm tractor. Only diesel power was available from a four-cylinder ohv of 137.89 cu.ins. indirect injection engine made by the Standard Motor Co, Coventry (the same engine as used in the earlier Coventry built Massey Ferguson 35 tractors). As the name may imply, the tractor had about 40 horsepower.Transmission was 8 speed through a single clutch with the option of the Allis-Chalmers half shaft clutch to achieve 'live' power take-off. Converging three point linkage was powered by an engine mounted hydraulic pump giving hydraulic power whenever the engine was running regardless of transmission status. An hydraulic weight transfer system was built in to increase traction and a simple mechanical depth stop was provided on the earlier machines. Later machines, introduced mid-1963 and called 'Depthomatic' had a draught and position control system. Other modifications and options included improved gear ratios; a pick-up hitch; an increase in power through higher maximum revs and revised battery arrangement. An option on both models was the patent Allis-Chalmers PAVT rear wheels (Power Adjusted Variable Track),a system adopted by other manufacturers after patents expired. Production ended in 1968 and quite a few are still in use on farms in 2011. A few ED40s were exported to the USA. It's hard to say exactly how many made it to the US, but it seems most of them ended up in the Mid-Atlantic and South Eastern regions.

Auger (drill)

An auger is a drilling device, or drill bit, that usually includes a rotating helical screw blade called a "flighting" to act as a screw conveyor to remove the drilled out material. The rotation of the blade causes the material to move out of the hole being drilled.

Brush hog

A brush hog or "bush hog" is a type of rotary mower. Typically these mowers attach to the back of a farm tractor using the three-point hitch and are driven via the power take-off (PTO). It has blades that are not rigidly attached to the drive like a lawnmower blade, but are on hinges so if the blade hits a rock or stump, it bounces backward and inward, and then centrifugal force makes it go outwards again.

The rotary blades are not sharpened in the same way as a conventional mower blade. They are usually quite dull so they whack through dense plant growth, whereas a sharp blade often gets stuck or slowed down. The blades are very heavy, up to an inch thick, so the centrifugal force pulling out is stronger than the forces of the vegetation bouncing in. They are made of heat treated high carbon steel that can withstand strikes with hard objects such as rocks and stones.

Cultivator

A cultivator is any of several types of farm implement used for secondary tillage. One sense of the name refers to frames with teeth (also called shanks) that pierce the soil as they are dragged through it linearly. Another sense refers to machines that use rotary motion of disks or teeth to accomplish a similar result. The rotary tiller is a principal example.

Cultivators stir and pulverize the soil, either before planting (to aerate the soil and prepare a smooth, loose seedbed) or after the crop has begun growing (to kill weeds—controlled disturbance of the topsoil close to the crop plants kills the surrounding weeds by uprooting them, burying their leaves to disrupt their photosynthesis, or a combination of both). Unlike a harrow, which disturbs the entire surface of the soil, cultivators are designed to disturb the soil in careful patterns, sparing the crop plants but disrupting the weeds.

Cultivators of the toothed type are often similar in form to chisel plows, but their goals are different. Cultivator teeth work near the surface, usually for weed control, whereas chisel plow shanks work deep beneath the surface, breaking up hardpan. Consequently, cultivating also takes much less power per shank than does chisel plowing.

Small toothed cultivators pushed or pulled by a single person are used as garden tools for small-scale gardening, such as for the household's own use or for small market gardens. Similarly sized rotary tillers combine the functions of harrow and cultivator into one multipurpose machine.

Cultivators are usually either self-propelled or drawn as an attachment behind either a two-wheel tractor or four-wheel tractor. For two-wheel tractors they are usually rigidly fixed and powered via couplings to the tractors' transmission. For four-wheel tractors they are usually attached by means of a three-point hitch and driven by a power take-off (PTO). Drawbar hookup is also still commonly used worldwide. Draft-animal power is sometimes still used today, being somewhat common in developing nations although rare in more industrialized economies.

Daimler-Benz DB 603

The Daimler-Benz DB 603 engine was a German aircraft engine used during World War II. It was a liquid-cooled 12-cylinder inverted V12 enlargement of the DB 601, which was in itself a development of the DB 600. Production of the DB 603 commenced in May 1942, and with a 44.52 litre displacement figure, was the largest displacement inverted V12 aviation engine to be produced and used in front line aircraft of the Third Reich during World War II.

The DB 603 powered several aircraft, including the Do 217 N&M, Do 335, He 219, Me 410, BV 155 and Ta 152C.

EMD 567

The EMD 567 is a line of large medium-speed diesel engines built by General Motors' Electro-Motive Division. This engine, which succeeded Winton's 201A, was used in EMD's locomotives from 1938 until its replacement in 1966 by the EMD 645. It has a bore of 8 1⁄2 in (216 mm), a stroke of 10 in (254 mm) and a displacement of 567 cu in (9.29 L) per cylinder. Like the 201A, the EMD 645 and the EMD 710, the EMD 567 is a two-cycle engine.

EMD's chief competitor, GE, now makes EMD-compatible replacement parts.

Farmall 1026

The Farmall 1026, produced by International Harvester from 1970–1971, is a row crop tractor with a hydraulic drive system, or hydro. Rated at 112 power take off, (PTO) horsepower, the Farmall 1026 was the first 100+ horsepower hydro tractor ever produced.

The 1026 was produced as a hydro only model. This was unique to this model, as the other hydro models produced by International Harvester at the time were also built as gear drive versions in addition to the hydro versions, while still maintaining the same model number. The Farmall 656 and 826, for example, were available in hydro and gear drive versions.

Fire-float Pyronaut

Pyronaut (originally Bristol Phoenix II) is a specialised form of fireboat known as a fire-float. It was built in 1934 by Charles Hill & Sons Ltd., Albion Dock Bristol, Yard No. 208. Registered number 333833. She is owned by Bristol Museums and based at M Shed in Bristol's Floating Harbour.

Originally powered by two Petter Atomic diesel engines rates at 55 bhp (41 kW) each. Two Merryweather & Sons three-cylinder reciprocating pumps capable of delivering 500 imperial gallons (2,300 l; 600 US gal) of water per minute.

This equipment was replaced in 1968 by two Ruston & Hornsby 6YDM six-cylinder diesel engines rated at 90 bhp (67 kW) each, driving screw propellers from the front power-take-off, and Coventry Climax centrifugal pumps capable of delivering 1,000 imperial gallons (4,500 l; 1,200 US gal) of water per minute from the main drive.

GAZ 46

The GAZ-46, army designation MAV (Russian, малый автомобиль водоплавающий, small floating car), is a Russian-made light four-wheel drive amphibious military vehicle that entered service in the 1950s and has been used by many Eastern Bloc allied forces since.

During the Second World War Canada, Britain and the US forwarded large quantities of military materials to Russia. Among those were jeeps, trucks, and amphibious vehicles like the 6x6 DUKW and the 4x4 Ford GPA. The latter were used to help men and equipment get across the many rivers of Eastern Europe and combat the Germans. Seeing merits of such vehicles, after the war, Russia decided to develop two similar vehicles, using domestic automotive parts, the BAV, an equivalent of the DUKW, and the MAV, an equivalent of the Ford GPA.

Due to bad reception of the Ford GPA 'Seep' by Allied soldiers, most of them were routed to Russia under the US Lend-Lease program, before production was halted prematurely in 1943. The research institute NAMI developed a prototype NAMI-011, basing on GAZ-67B parts, in 1949. The authorities decided, that it should be manufactured in GAZ works, as GAZ-011, but the factory was reluctant, because a design needed much perfecting, while the GAZ-67B was obsolete and due to be replaced with GAZ-69.As a result, an improved model GAZ-46 was built using the frame and parts of the GAZ-69 4x4 half-ton light truck, of which production started with the Gorki factory of 1952. The principal functions of the GAZ-46 MAV were to make light work of crossing lakes and rivers for men and materials, as well as performing river reconnaissance. As of the end of the fifties the latter role became reserved for the BRDM-1, a much more powerful 4x4 amphibious vehicle.

The GAZ-46 MAV used the mechanics of existing Russian GAZ 4x4 "jeeps" as well as being created somewhat bigger for better buoyancy, and its design is heavily inspired by that of the wartime Ford GPA. Just like the 'Seep', its hull is entirely out of steel, welded to a steel chassis. The layout is the same: engine compartment in the front, crew compartment in the center, and the spare wheel horizontally mounted on the rear deck. The driver and the commander of the vehicle have individual seats in the front with a three-seat bench behind them. The windshield can be folded down, and if necessary, a cover can be installed to close the cockpit. The engine is coupled to a manual three-speed gearbox and a two-speed transfer-case. Also, there is a screw-propellor for in the water propulsion, driven by a power take-off, and a proper rudder provides good maneuverability. Front and rear suspension is in the form of leaf-sprung rigid live axles. Thanks to its steeply raked front and rear and four-wheel drive, the GAZ can manage reasonably steep river banks before swimming across.

H engine

An H engine (or H-block) is an engine configuration in which the cylinders are aligned so that if viewed from the front, they appear to be in a vertical or horizontal letter H.

An H engine can be viewed as two flat engines, one atop or beside the other. The "two engines" each have their own crankshaft, which are then geared together at one end for power-take-off. The H configuration allows the building of multi-cylinder engines that are shorter than the alternatives, sometimes delivering advantages on aircraft. For race-car applications there is the disadvantage of a higher centre of gravity, not only because one crankshaft is located atop the other, but also because the engine must be high enough off the ground to allow clearance underneath for a row of exhaust pipes. The power-to-weight ratio is not as good as simpler configurations employing one crankshaft. There is excellent mechanical balance, especially desirable and otherwise difficult to achieve in a four-cylinder engine.Two straight engines can be similarly joined to provide a U engine.

Log splitter

A log splitter is a piece of machinery or equipment used for splitting firewood from softwood or hardwood logs that have been pre-cut into sections (rounds), usually by chainsaw or on a saw bench. Many log splitters consist of a hydraulic or electrical rod and piston assembly and these are often rated by the tons of force they can generate. The higher the force rating, the greater the thickness or length of the rounds that can be split. The log splitter consists of all four major hydraulic components.

Most log splitter models for home use have a rating around 10 tons, but professional hydraulic models may exert 30 tons of force or more. There are also manual log splitters, which use mechanical leverage to force logs through a sharpened blade assembly; and screw or 'corkscrew' types that are driven directly from an agricultural tractor's power take-off shaft where the splitter is mounted on the three point linkage.

Manure spreader

A manure spreader or muck spreader or honey wagon is an agricultural machine used to distribute manure over a field as a fertilizer. A typical (modern) manure spreader consists of a trailer towed behind a tractor with a rotating mechanism driven by the tractor's power take off (PTO). Truck mounted manure spreaders are also common in North America.

Non-synchronous transmission

A non-synchronous transmission is a form of transmission based on gears that do not use synchronizing mechanisms. They are found primarily in various types of agricultural and commercial vehicles. Because the gear boxes are engineered without "cone and collar" synchronizing technology, the non-synchronous transmission type requires an understanding of gear range, torque, engine power, range selector, multi-functional clutch, and shifter functions. Engineered to pull tremendous loads, often equal to or exceeding 40 tons, some vehicles may also use a combination of transmissions for different mechanisms. An example would be a power take-off.

Oscillating Water Column

Oscillating Water Columns (OWCs) are a type of Wave Energy Converter (WEC) that harness energy from the oscillation of the seawater inside a chamber or hollow caused by the action of waves. OWCs have shown promise as a renewable energy source with low environmental impact. Because of this, multiple companies have been working to design increasingly efficient OWC models.

OWC are devices with a semi-submerged chamber or hollow open to the sea below, keeping a trapped air pocket above a water column. Waves force the column to act like a piston, moving up and down, forcing the air out of the chamber and back into it. This continuous movement force a bidirectional stream of high-velocity air, which is channelled through a Power-Take-Off (PTO). The PTO system converts the airflow into energy. In models that convert airflow to electricity, the PTO system consists of a bidirectional turbine. This means that the turbine always spins the same direction regardless of the direction of airflow, allowing for energy to be continuously generated. Both the collecting chamber and PTO systems will be explained further under "Basic OWC Components."

Power tower

Power tower may refer to:

Power Tower, a thrill ride at Valleyfair and Cedar Point amusement parks in the USA

Power tower (power take-off), a type of mechanical power take-off (PTO)

Solar power tower, a type of solar power plant

Tetration, a mathematical operation also known as power tower, hyperpower, or superexponentiation

Transmission tower, usually a tall steel lattice tower supporting an overhead electric power line (aka electricity pylon, hydro tower, etc.)

Power tower (exercise), equipment can include pull up handles, dip bars, push up grips and captain's chair forearm pads

Power tower (Linz), an office building in Linz, Austria

Power tower (power take-off)

A power tower is a type of mechanical power take-off (or pto) which resides on an auxiliary transmission. It is mounted to the top of an auxiliary transmission (also known as a brownie or joey box) and its vertical housing has earned it the name power tower. Unlike traditional transmission or engine mounted power take-offs the power tower can provide the engine's full rated power output. It is commonly used to drive large winches or hydraulic pumps. Unlike the power take-off of an agricultural tractor, the attachment of any device to the power tower is usually permanent.

The power tower can also refer to a stand-alone gear box which provides the same function as a power tower, but does not provide any gearing for the output shaft to the drive wheels.

Telescopic handler

A telescopic handler, also called a telehandler, teleporter, or boom lift, is a machine widely used in agriculture and industry. It is somewhat like a forklift but has a boom (Telescopic cylinder), making it more a crane than a forklift, with the increased versatility of a single telescopic or articulating boom that can extend forwards and upwards from the vehicle. On the end of the boom the operator can fit one of several attachments, such as a bucket, pallet forks, muck grab, or winch. Telehandlers are sometimes called cherry pickers in North America, as that name can refer to any truck or heavy equipment that has such a boom.

In industry the most common attachment for a tele-handler is pallet forks and the most common application is to move loads to and from places unreachable for a conventional forklift. For example, telehandlers have the ability to remove palletised cargo from within a trailer and to place loads on rooftops and other high places. The latter application would otherwise require a crane, which is not always practical or time-efficient.

In agriculture the most common attachment for a tele-handler is a bucket or bucket grab, again the most common application is to move loads to and from places unreachable for a 'conventional machine' which in this case is a wheeled loader or backhoe loader. For example, telehandlers have the ability to reach directly into a high-sided trailer or hopper. The latter application would otherwise require a loading ramp, conveyor, or similar.

The telehandler can also work with a crane jib along with lifting loads, that attachments that include on the market are dirt buckets, grain buckets, rotators, power booms. The agricultural range can also be fitted with three point linkage and power take-off.

The advantage of the telehandler is also its biggest limitation: as the boom extends or raises while bearing a load, it acts as a lever and causes the vehicle to become increasingly unstable, despite counterweights in the rear. This means that the lifting capacity quickly decreases as the working radius (distance between the front of the wheels and the centre of the load) increases. When used as a loader the single boom (rather than twin arms) is very highly loaded and even with careful design is a weakness. A vehicle with a 5,000 lb (2.5ton) capacity with the boom retracted may be able to safely lift as little as 400 lb (225 kg) with it fully extended at a low boom angle. The same machine with a 5,000 lb lift capacity with the boom retracted may be able to support as much as 10,000 lb (5ton) with the boom raised to 70°. The operator is equipped with a load chart which helps him determine whether a given task is possible, taking into account weight, boom angle and height. Failing this, most telehandlers now utilize a computer which uses sensors to monitor the vehicle, and will warn the operator and/or cut off further control input if the limits of the vehicle are exceeded, the latter being a legal requirement in Europe controlled by EN15000. Machines can also be equipped with front stabilizers which extend the lifting capability of the equipment while stationary, as well machines with are fully stabilised with rotary joint between upper and lower frames, which can be called mobile cranes although they can typically still use a bucket, and are also often referred to as 'Roto' machines. They are a hybrid between a Telehandler and small crane.

Telehandlers were pioneered by the Matbro company at Horley in Surrey, England, UK, which developed them from their articulated cross country forestry forklifts. At first they had a centrally mounted boom on the front section, with the driver's cab on the rear section, as in the Teleram 40, but the rigid chassis design with a rear-mounted boom and cab to the side has become more popular.

Tractor

A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction. Most commonly, the term is used to describe a farm vehicle that provides the power and traction to mechanize agricultural tasks, especially (and originally) tillage, but nowadays a great variety of tasks. Agricultural implements may be towed behind or mounted on the tractor, and the tractor may also provide a source of power if the implement is mechanised.

Wave power

Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC).

Wave power is distinct from tidal power, which captures the energy of the current caused by the gravitational pull of the Sun and Moon. Waves and tides are also distinct from ocean currents which are caused by other forces including breaking waves, wind, the Coriolis effect, cabbeling, and differences in temperature and salinity.

Wave-power generation is not a widely employed commercial technology, although there have been attempts to use it since at least 1890.In 2000 the world's first commercial Wave Power Device, the Islay LIMPET was installed on the coast of Islay in Scotland and connected to the National Grid. In 2008, the first experimental multi-generator wave farm was opened in Portugal at the Aguçadoura Wave Park.

ISO standards by standard number
1–9999
10000–19999
20000+

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.