The drum is the term used to refer to the casing on the roller body. A distinction is made between smooth drums, padfoot drums and other special forms of drum. The vibration system is located in the drum. The weycor system consists of an exciter shaft that has a fixed eccentric weight. In the weight there is a metallic housing in which a flexible mass can be moved into an eccentric position by means of centrifugal force. The variable mass consists of steel balls with a diameter of 3 mm.
Changing the direction of rotation alters the position of the centre of gravity of this moving mass. Depending on the direction of rotation of the vibration shaft, the mass of the steel balls is added to or subtracted from the fixed eccentric mass. In the case of addition, the existing static unbalanced mass becomes even greater because the variable mass is added to it. Large vibration amplitudes are generated for deep compaction. In the case of subtraction, the counteracting weight of the variable mass partially offsets the static unbalanced mass on the exciter shaft. The amplitude is smaller for surface compaction. Depending on the speed of rotation, various centrifugal forces can be achieved. The total force comprises the vibrating mass of the drum and the components fixed to it. This gives the compacting power of the machine.
“bauma” is the largest and most important trade fair in the field of construction machinery. This trade fair also runs in a three-year cycle and is organised by “Neue Messe München” on the site of the former airport at Munich-Riem. The trade fair was held on the Theresienwiese in central Munich up to 1995, then for the first time on the new trade fair site in Riem in 1998. The exhibition area has been extended regularly and now extends much further than the original site. The trade fair company therefore rents space from the city of Munich and constructs several pedestrian bridges over a busy road to provide access to the additional site. Nevertheless, the waiting list for exhibitors is long. It is simply impossible for a visitor to cover the entire trade fair in one day. You have to plan to spend several days there, as the impact of the trade fair’s crowd of visitors, its technology, its variety of exhibits and the entertainment it provides is considerable. It’s easy to see why the trade fair’s motto is “THINK BIG”.
All manufacturers develop and exhibit new products at and for “bauma” because the proportion of international visitors and exhibitors is very high, which means that potential customers from overseas, who are difficult to reach otherwise, can also be targeted. Neue Messe München is also expanding with the offshoots "bauma China", "bauma India" and "bauma South Africa" into so-called newly industrialised countries.
The trade fair covers the entire area of the halls and the open-air space. Suppliers are mostly to be found in the halls, while the construction machine manufacturers always set up their own new exhibition town on the open-air site. Setting up begins as much as 6 months before the trade fair itself opens in some cases, while dismantling lasts for about 2 months, until the end of May.
Our stand is traditionally located in the real core area of “bauma”, immediately by the EAST entrance, which leads out to the open site. You will find us here in 2016 too: Open-air site FM808
Facts from 2013:
Around 530,000 visitors from more than 200 nations
A total of 3,420 exhibitors – 1,346 national and 2,074 international companies – from 57 countries
570,000 square metres of exhibition space
A distinction is made between self-locking differentials and connectable differentials. With self-locking differentials, the differential locks automatically when the wheels are moving at different speeds. As a result, a self-locking ratio is reached even when going round a normal bend without the driver being able to affect it. The wheels scrape on the surface, the loader drifts to the outer radius of the bend. On firm ground in particular, this leads to additional load and wear on the tyres. On looser ground, such as newly laid road surfaces, levelled surfaces or lawns, the tyres damage the subsurface.
With the connectable differential lock, the differentials of the axes are only locked by the driver when required and with a complete lock i.e. the same distribution of drive force over all wheels. In normal driving, the differentials equalise the different speeds of the wheels and the wheel loader remains on track round bends. This protects the tyres and the subsurface.
Weycor wheel loaders from the AR 60 model have a 100% connectable differential lock and rigid axles with planetary reduction gears. The result is powerful propulsion and high traction.
A diesel particle filter is a device for reducing the particles present in the exhaust gas from diesel engines. The particle filter is also sometimes called a diesel particle filter (DPF), after the origin of the particles, or a soot particle filer (SPF), after the composition of the particles. There are two functional types, which differ fundamentally: wall-flow filters, in which the exhaust fumes pass through a porous wall in the filter, and full-flow filters (bypass filters), in which the exhaust fumes flow along the inner surface of the filter.
In a wall-flow filter, the exhaust gas containing soot particles is filtered as it passes through a porous filter wall. The particles are caught by surface filters, mainly on the surface of the filter wall, or remain inside the filter wall by a process of deep filtration. Larger particles cannot pass through the filter wall and are therefore deposited on its surface. In this way, layers of up to 200 µm can form on the channel surface before the filter is regenerated. All wall-flow filters have in common the fact that they have a very high separation rate (over 95%) of the total mass of particles, a figure that remains constant over long periods, and produce only a small increase in fuel consumption. This additional consumption is a result, on the one hand, of the regeneration process, which requires additional consumption for post-injection of fuel or for generating electrical energy for the heating coil, and on the other of the increase in exhaust gas back pressure caused by the particles deposited in the filter.
Bypass filters usually work on the principle of deep-bed filtration in the bypass flow. The structure is such that part of the exhaust gas flow is diverted by a fleece or similar into the neighbouring channels and the soot particles are filtered out. However, the exhaust gas flow is not forced through the fine pores of the wall. If the diesel soot particles cause an overload, the partial exhaust gas flow is fed out through the normal longitudinal channels. Bypass flow filters mostly work on the CRT (continuous regeneration trap) principle. Because the exhaust gas flow in a bypass deep-bed filter is not forced completely through a fine-pored wall, the effectiveness of the filtration is significantly lower. The total mass of particles is reduced by 30 - 40%, more in some cases. However, as a large part of the exhaust gas flow does pass along the layer of fleece in a longitudinal direction, the ultrafine particles (diameter < 400 nm) that are particularly harmful to health are reduced by about 80% through diffusion/adhesion in bypass flow deep-bed filters. When retrofitting vehicles with bypass flow deep-bed filters, no changes are required to the vehicle other than fitting the exhaust gas treatment system to the exhaust, because it is practically impossible for the exhaust back pressure to reach unpermitted values in standard systems. The filter effectiveness depends heavily on the filter design, vehicle, operating conditions and states (including over time) and the interaction of these factors.
Regeneration of the filter is carried out by burning off the deposited particles. This becomes necessary when the particle deposits create a high exhaust back pressure, which hinders the emission of the exhaust fumes. A parameter that makes it possible to determine the degree of clogging of the filter and is easy to measure is the differential pressure across the filter. As this differential pressure varies depending on engine speed, load state and load size, these parameters must be recorded in a characteristic map. Monitoring of the differential pressure and initiation and control of the regeneration process are carried out by the engine control system of the diesel engine. Regeneration can be completed by post-injection, an oxidizing converter, a heating coil, catalytically or with additives. Under certain circumstances, regeneration can be carried out continuously, but still always selectively during downtimes.
In traditional single drum rollers, the hydrostatic drive of the vibration unit depends on the diesel engine speed. The consequence of this is that the diesel engine has to be run at “full load” to provide the appropriate speed of rotation of the exciter shaft. This is irrespective of whether the power of the engine at max. speed is actually needed.
With the “ECO-Speed” option, the speed of the diesel engine can be reduced by approx. 400 rpm while optimising engine torque. The drive pump of the hydrostatic drive on the vibration unit controls the volume flow in such a way that the speed of rotation of the exciter shaft is not affected. The pump and motor always provide the “right” speed of the vibration shaft in the closed circuit of the vibration drive. Another consequence is that the noise load is reduced by approx 13 dBA and there is a fuel saving of approx. 10% - 12%. The pump is adjusted electronically by means of a controller on it, which receives information about the speed of the diesel engine via the CAN bus. If the diesel engine is depressed by the drive pressure, the engine speed increases with simultaneous adaptation of the speed of the exciter shaft.
In summary this means: the engine speed can be lowered with “ECO-Speed”, while full power is still available in the hydraulic system. Fuel consumption and noise level fall, vibration frequencies and centrifugal forces remain unaffected.
A spring-loaded or negative brake is a brake unit used with heavy vehicles. The brake linings are pressed purely mechanically against the brake disk or brake drum by spring force. In order to release the brake, a force must therefore be applied, which is normally achieved pneumatically or hydraulically. Spring-loaded brakes work according to the principle that if the actuation medium fails (e.g. as a result of a leak), the brake still works – they can therefore be used as emergency or hand brakes.
The spring-loaded or negative brake in weycor wheel loaders is a closed brake system (oil bath multiple-disc brake) which holds the wheel loader securely in position on a slope when the brake or inch function is activated and automatically locks all four wheels when the engine is at a standstill. The multiple-disc brake runs in the oil bath and is particularly low-maintenance and low-wearing as a result.
The oil bath multiple-disc brake is a special type of disc brake in which fixed brake linings slow down the brake disc that runs in the oil bath by pressure.
This drive is found in many working machines and ground conveyors. A hydrostat facilitates continuous driving, braking and reversing. Continuous hydrostatic drives convert the mechanical power of a drive unit (diesel engine) into hydraulic power by means of a pump. The hydraulic power can be transmitted easily and turned back into mechanical power in consumers. By introducing fluid into cylinders under pressure, the pistons and piston rods in them are caused to move in a straight line, which can be used for work processes or to drive machines; hydro-motors convert that energy into a rotary movement. Hydrostatic drives are an optimal type of gearing in terms of energy when continuous adjustment of speed on the work side is required. Hydrostatic drives are widely used in wheel loaders. Among other things, a hydrostat improves manoeuvrability, allows very precise gear control, facilitates gear changes without affecting traction and is highly efficient. When moving the shovel into the bulk material, there is significantly less loss of energy than with gearing involving a hydrodynamic transducer and a powershift transmission. We only use components from the German manufacturers Bosch Rexroth or Linde in our wheel loaders.
During inching, pressing the inch pedal with hydrostatic drives separates the travel drive from the conveying and lifting functions. Ideally, a third pedal is provided for inching, alongside the accelerator and brake pedals. This is operated with the left foot and facilitates both slow driving manoeuvres with simultaneously high lifting force and vice versa, since in working machines with a hydrostatic drive, the output depends on the speed of the drive engine. In order to cope with the requirements of movement and use of a hoist with different outputs, inching is therefore required.
We are the only manufacturer to offer a separate inch pedal, with our weycor wheel loaders. This prevents the possibility of moving against the operating brake, in contrast to the combination of a brake/inch pedal. A generously proportioned inching range facilitates precise distribution of shearing and lifting forces. The result: less wear and lower fuel consumption.
The “Intermat” trade fair on the Paris-Nord Villepinte exhibition site is one of the three leading international trade fairs in the construction machinery sector. It runs in rotation with “bauma” in Munich and “Conexpo” in Las Vegas and thus takes place in a
three-year cycle. Construction machinery, attachments and technological solutions in this area are exhibited.
1,300 exhibitors from 37 countries
Exhibition space of 375,000 m² in the halls
A demonstration area of 30,000 m² on the external site
200,000 visitors from 148 countries
50 international delegations from 25 countries
Paris Nord Villepinte Exhibition Centre
95970 ROISSY CDG CEDEX
Articulated-pendulum joints (Articulated-swivel joint)are used to provided a movable link between the rear and front frames of agricultural and construction machines. The machine can be steered by means of an angular movement around a horizontal axis, while the rear carriage can swing in the vertical axis. The advantage of the articulated-swivel joint is the fact that the front and rear carriage run on one track. The attachment can be positioned precisely without moving the entire machine but simply be swivelling the front carriage. The oscillation offsets unevenness in the ground and creates even wheel pressure. In combination with rigid axles, good cross-country mobility is provided. The structurally low position of the point of rotation of the swivel joint in conjunction with the low centre of gravity of the machine provides good stability.
In weycor wheel loaders, we use robust, low-maintenance articulated-swivel joints almost exclusively in conjunction with rigid axes. With an oscillation of ±12° in the rear carriage and an articulation angle of 40°, these provide outstanding cross-country mobility, protect the ground and offer extreme manoeuvrability. With their low centre of gravity, weycor wheel loaders have a high tilt stability even under extreme conditions. Many manufacturers limit the articulation angle to below 40° to ensure stability. With regular servicing and maintenance, the articulated-swivel joint can be relied on over a long service life. The 75e S and 75e T models are exceptions. These machines have an articulated joint and a rear pendulum axle.
Tractive force: The force that can be transmitted into the ground by chains or wheels when the necessary traction is present.
Lifting force: A vertical force that is generated by a lifting cylinder. It results from the power of the lifting cylinder and the leverage of the lifting arm, and is applied at the centre of gravity of the shovel.
Tear-out force: Vertical force on the front edge of the shovel floor or the blade. It is generated by the tip cylinder.
A no-spin differential is a special form of self-locking differential. If different wheel speeds come about when travelling around bends, the differential decouples automatically. Only the clutch disc on the side that is rotating more slowly is engaged and this transfers the full torque until the rotational speed of the wheels equalises again. The self-locking differential is permanently engaged, providing good traction.
More details: https://www.youtube.com/watch?v=Zt0t4PKTiow
According to EN 474-3, the load capacity of the loading shovel must not exceed 50% of the tipping load in wheel loaders when the wheel loader is cornering fully.
In parallel kinematics loaders, the tilt cylinder applies force to the centre of the bell crank, as a result of which the cylinder rod is positioned horizontally to the lifting arm. Guiding of the tool is more precise, especially when using a pallet fork, because the tool remains in the same position even at the top, when raising the hoist, as it was at the bottom. Compared to Z-kinematics, the breakaway and tear-out force is lower, however, because the oil pressure is applied on the piston rod side; as a result, this form of kinematics is mainly used in goods handling and transport.
The centre of gravity of the machine is less favourable when using a rear pendulum axle in combination with an articulated joint because it is higher than the combination of a rigid axle and an articulated-swivel joint. It moves upwards by a maximum of the distance of the pendulum movement (approx. ±8 - 12°), which has a negative impact on stability. As compensation, an axle load is often used in the lower rear area of the machine to provide better stability. Moreover, the cross-country mobility of articulated-swivel joint loaders cannot be achieved.
In the weycor 75e S swivel loader, we still use a pendulum axle in conjunction with an articulated joint, so that the weight of the rear frame contributes to the stability of the loader as soon as the hoist is swivelled by up to 90° to left or right. This goes significantly beyond the angle of articulation that is otherwise usual, which is a maximum of 40° in our wheel loaders with articulated-swivel joints and rigid axles. In the 75e S, the pendulum axle also locks automatically by means of a hydraulic cylinder, controlled by position sensors on the hoist. The weycor 75e T model is also equipped with a pendulum axle because of the length of the hoist when fully extended.
Wherever material has to be picked up and transported over short distances, wheel loaders are used nowadays. Wheel loaders belong to the group of self-propelled working machines and they differ fundamentally in terms of type of drive, steering and kinematics. As far as the drive is concerned, hydrostats or converters are used. Steering is carried out by articulated-swivel joints with rigid axles, articulated joints with rear pendulum axles or steering knuckles with an undivided frame. In the area of kinematics, two main types are widely used, Z-kinematics and parallel kinematics.
The areas of application are varied: mainstream construction industry, recycling, extraction, garden and landscape construction, transport and municipal applications. In general, wheel loaders are welcome handling machines in the commercial field for a wide range of bulk and piece goods. With a wide variety of attachments, special applications can also be handled.
Bulk weight or bulk density are the terms used for the specific density (mass per volume) of a quantity of bulk material. The bulk weight is given in t/m³.
Some typical bulk weights in t/m³:
Asphalt, broken 0.7 - 0.95
Concrete gravel 2.3
Iron ore 1.6 - 3.2
Cereal, wet 0.88 - 1
Wood, wet 0.9
Wood, dry 0.7
Lime sandstone 1.8
Limestone 2.7 - 2.9
Gravel, wet 2.0
Clinker bricks 2.0
Loam and clay 2.1
Corn, husked 0.75
Mixed feed 0.5
Topsoil, wet 1.6 - 1.8
Sand and gravel, wet 2.0
Sand and gravel, dry 1.8
Reinforced concrete 2.5
Ballast 1.5 - 1.8
Cement, shaken 1.9
Brick 1.8 - 2.0
Sugar 0.7 - 1.0
Selective catalytic reduction - A process for reducing nitrogen oxides. An aqueous urea solution (AdBlue, for example) is injected continuously into the exhaust gas flow, from which carbon dioxide and ammonia are made by hydrolysis, the splitting of a (bio)chemical link by reaction with water. The ammonia that is created in this way turns the nitrogen oxide in the exhaust gas into normal nitrogen. The SCR process is now used in numerous utility vehicles, above all to bring the exhaust gas threshold values down below Euro 4, Euro 5 and Euro 6.
The static tipping load (kg) defines the value at which the rear wheels are just lifted off the ground by the weight at the centre of gravity of the working load in the shovel. These figures are crucial for stability and therefore for industrial safety. The key figure is when the hoist is extended and the loader is fully turned.
When using a pallet forklift, these figures are reduced significantly in line with the law of levers because the centre of gravity of the load moves outwards away from the centre of gravity by half the length of the pallet fork used. The static tipping load when using forklifts also applies to the articulated position, with the hoist extended; this is the most unfavourable load state for the wheel loader. The loads on the pallet forks are also limited by a stability factor under legislation. When moving close to the ground over a level surface, the load capacity is a maximum of 80% of the static tipping load when pallet forks are being used; on uneven ground, this figure falls to 60%. In order to achieve better figures in day-to-day use, articulation and pendulum angles are often restricted at the expense of manoeuvrability. Additional counterweights are also used or the rear tyres are filled with water so that a wheel loader can be used for loads in a range that would actually require a larger machine to be purchased. However, these measures always lead to increased wear. Other important parameters for the use of wheel loaders are the shovel contents, the dump height and the breakout force.
Earth-moving machines may only be driven on public roads if they are equipped in accordance with the German Road Traffic Licensing Regulations and the Highway Code and the driver holds the relevant licence.
Driving licence required (section 6 of the Driving Licence Regulations):
> At a maximum design speed of 6 kph, driving without a licence is permitted.
> If the maximum design speed is no more than 25 kph, driving licence class L is required without weight limitation.
If the maximum design speed is over 25 kph:
> for earth-moving machines with a permitted total weight up to3.5 t, European driving licence B is required
> for earth-moving machines with a permitted total weight up to 7.5 t, European driving licence C1 is required
> for earth-moving machines with a permitted total weight over 7.5t, European driving licence C is required
If the maximum design speed is greater than 20 kph, the vehicle must have its own registration number. If the maximum design speed is less than 20 kph, a sign must be provided on the left side of the vehicle showing:
First name and surname
Place of residence (company and registered office)
under section 64b of the
Road Traffic Licensing Regulations.
> General Operating Licence
> Driving Licence
> Test report in accordance with VGB 40 section 50 (expert test)
Compaction of various materials is the job of rollers. The type of ground determines the compaction effort (or the machine type) required to achieve the desired compaction results. In practice, a distinction is made between cohesive and non-cohesive soil. In cohesive soil, the particles attach and stick to one another. Only cohesive soil like clay or loam can be kneaded to form a ball. Cohesive soil is best compacted with a padfoot drum that has a kneading action with overlaying vibration. In non-cohesive soil, the soil particles are larger and do not adhere or stick to one another. These types of soil are best compacted with a smooth drum.
The vibration reduces the frictional forces of the material in the soil and minimises the empty spaces. This results in better layering and support for the material. The aim is to reduce the empty spaces as much as possible so that the material can interlock. Only a well-compacted subsurface enables the layers built upon that subsurface to be well compacted too.
A crucial factor in the compaction performance is the depth of material on which the machine is used. The correct depth is determined by the type of material and the machine to be used. Large material depths require heavy rollers with a large amplitude and high impact force to ensure that the material is penetrated. Lighter rollers are used on shallower amounts of material.
Damp loam and clay-like material are compacted with padfoot drums. The smooth drum follows up as soon as the correct moisture level is reached.
Sand is compacted with a small amplitude, also only statically in some cases. Too much compaction energy can shift the material. Sand is also mixed with lime to give a material that can be compacted.
Broken material (ballast, gravel):
Broken material provides a solid base with a high load-bearing capacity. The stone material must be compacted from the ground up to the surface. Various layer thicknesses must be used depending on the compaction power of the machine. It must be ensured that the stone is not broken in the process, as it will lose its load-bearing capacity.
This compaction uses the dead weight of the front carriage (axle load) alone to compact the subsurface. No dynamic compaction takes place. A crucial factor in choosing a machine is the static line load and the diameter of the drum.
Compaction with vibration:
This compaction uses the forces generated by rotation of eccentrically positioned masses and the dead weight of the roller body to compact the subsurface. This dynamic force is created by rotating an eccentric weight inside the drum. This rotation generates a centrifugal force that is sufficient to lift the weight of the steel drum and allow it to fall again. This cycle is repeated 25 to 40 times per second as the machine moves over the surface. The crucial criteria in choosing a machine are the static line load, vibrating mass, frequency and amplitude.
Types of soil:
Clay: Soapy and sticks easily.
Silt: Floury, feels very soft, very fine, dry soil particles can be ground up easily.
Sand: Very fine and usually rolls off very easily.
Gravel: Diameter from 5 mm to several centimetres, also round and rolls off easily.
Rock: Various blocks, sizes and strengths, highest load-bearing capacity.
A single drum roller is a construction machine and is classified in the group of compaction machines. It can be used to compact large areas of cohesive and non-cohesive soils, base and frost protection layers. Sufficient compaction is required to ensure the load-bearing capacity and durability of the material that is brought in. The single drum roller is equipped with a roller drum with integrated vibration unit and air-filled tyres on the rear axle. The vibration system allows use for both deep and surface compaction by means of two selectable amplitudes and frequencies. High centrifugal forces and a low frequency are required for deep compaction, lower centrifugal forces and high frequencies for surface compaction. The important machine parameters for the compaction effect are the overall weight of the machine, the static line load, the vibrating mass, the amplitude and frequency.
Use of the small amplitude for compacting thin layers:
> Gravel, sand, mixed soils
> Gravel and ballast base layers
> Surface compaction
Use of the large amplitude for compacting thick layers:
> Non-cohesive and cohesive soils
> Gravel and ballast base layers
> Hydraulically bound base layers
> Frost protection layers
Areas of application:
> Farm roads, car parks
> Industrial construction
> Road building
> Motorway and heavy traffic road construction
> Airport and rail track construction
> Construction of dykes and embankments
This type of kinematics is characterised by a short, curved lifting arm with a central tilt level as a bell crank; the lifting and tilting cylinders are attached by hinges to the hoist. The maximum breakout force is achieved when the oil flow acts on the full surface of the piston. During dumping, the smaller surface on the piston rod side is supplied with oil, which generates greater speed and dumping can take place quickly. The parallel guide for pallet fork operation can be adjusted by minimal correction of the tipping cylinder.
weycor Z-kinematics is characterised by high frictional forces and excellent lifting heights. The very good parallel guide provides the optimal prerequisites for using pallet forks. When the hoist is lowered with the shovel, the shovel returns automatically to the digging position. The boom that is tapered towards the top provides the best possible view of the attachment and working area at all times, even under difficult operating conditions.