HAMM drum parts


The subassemblies of HAMM drums in detail

To make sure that your HAMM roller always delivers first-class results, it is essential that you regularly check the drum parts and, if necessary, replace them. The outstanding accessibility of all components and parts guarantees short machine downtimes in the case of maintenance or repairs.

Scraper

In daily construction site operations, using genuine HAMM scrapers keep the surfaces of drums and tyres clean and guarantees best paving and surface quality. The scrapers prevent dust and asphalt from adhering to the drum and tyres. The scraper materials optimised by HAMM are wear-resistant and ensure minimal operating costs.

Scrapers for pneumatic tyre rollers

Brushes are used as standard scrapers on pneumatic tyre rollers. If the machines are rolling on particularly adherent material, plastic scrapers adapted to the form of the tyres are used.

Plastic scrapers/plastic brushes for asphalt rollers

Flexible and durable scrapers made from plastics especially formulated for use on asphalt are used on asphalt rollers. The properties of the materials used in the production of HAMM scrapers are selected to ensure that optimal water distribution and perfect cleaning of the drum surfaces are simultaneously guaranteed. One consequence of this is considerably lower water consumption.

Scraper wear

Worn scrapers should be replaced as soon as the surfaces of the drums or tyres are no longer reliably cleaned. Particularly in the case of asphalt machines, utmost cleanliness must be consistently maintained to extend the service life of scrapers. Removal all material residues adhering to scrapers at regular intervals to ensure faultless functioning of the scraper system. Bent scraper holders are often the cause of improper cleaning of drums and tyres. In the course of daily inspections, always check for damage to the scraper mounting components.

Examples of wear:

Intact scraper

Worn scraper on a smooth drum

Intact scraper

Tyre damage caused by a worn scraper

Rubber buffer

Rubber buffers suppress vibrations transferred from the tyres or drums to the machine and ensure that the machine operator is undisturbed and able to concentrate on his work. This applies to both vibrating and oscillating drums. The rubber buffers are the most important suspension components of the drums. The hardness and form of rubber buffers for HAMM rollers are ideally matched to the respective roller types.

The optimal choice of the grade of hardness ensures that compaction force is transmitted to the ground with maximum effect. Incorrectly dimensioned rubber buffers can significantly reduce compaction performance.

If the wrong buffers are fitted, unsuppressed vibration and oscillation forces are transmitted directly to the entire machine. This can lead to damage of mechanical and electronic components, excessive and potentially harmful stress for the operator and negative effects on compaction quality.

Damage to rubber buffers and preventive maintenance

The rubber buffers should be checked for cracks and deformation in the course of every scheduled maintenance inspection.

Always replace damaged or defective rubber buffers in good time. This can significantly extend the service life of the other buffers, as a defective buffer can cause the unnecessary transfer of loading stresses to its remaining intact counterparts.

The service life of buffers depends to a great extent on where and for what tasks the machine is deployed. Continuous jump operation in the course of extremely demanding earthworks is a typical cause of premature wear on damping components.

Always use the machine under consideration of its operating weight and the scheduled task.

Example of wear:

Intact rubber buffer

Split rubber buffer

Sprinkling system

Always be on the safe side – with products from our range of sprinkling system parts: our reliable filters, high-quality pumps, spray nozzles, seals and couplings guarantee you trouble-free operations on hot asphalt .


Components

  • Spray nozzles:
    Each of the extremely water-efficient spray nozzles is fitted with fine sieves and is installed in a configuration that ensures complete wetting of the drums or tyres as required in all possible situations. Due to their positioning, they are protected against wind and can be watched by the operator during every job.
  • Water pump:
    Electric pressure sprinkling is taken care of by one or two alternately operating water pumps. While one pump is in use, the other is held in reserve as a backup.
  • Sprinkler bars:
    The sprinkler bars are designed as a quick-change system to make adjustment and maintenance work even more efficient. And, if frost is expected, the bars can simply be removed.
  • Antifreeze injection:
    The antifreeze injection option ensures that work can continue without interruption even at extremely low temperatures.
  • Plastic water tanks:
    The system’s plastic water tanks are integrated in the frame.
  • Driver Kits:
    The Driver Kits with genuine HAMM parts are particularly compact and take up very little space. This means that they can always be carried onboard the machine and allow, for example, the replacement of worn spray nozzles within just a couple of minutes.
  • Additive sprinkling:
    Optimised additive sprinkling for pneumatic tyre rollers enables an additive to be sprinkled onto the rubber tyres: The additive concentrate is simply poured into the additive tank of the machine without any need for pre-mixing. The dosage from the large additive tank with fill-level monitoring can be controlled from the operator's platform in a range of addition levels. The roller then automatically doses and mixes the additive during compaction in accordance with the specification. As the principle developed by HAMM avoids separation of the additive-water mixture, it also brings increases compaction quality. And last but not least, switching from water to additive can easily be done at any time directly from the operator's platform.

    WIRTGEN GROUP Asphalt Anti Stick additive is available in 5-litre and 20-litre canisters.

    The following animated film explains the principle of additive sprinkling in detail:

Overview of the various components of the sprinkling system

Water pump

Driver Kit

WIRTGEN GROUP Asphalt Anti Stick

Adjustments and maintenance

When using the water pump, it is advisable to switch to the back-up pump every now and again to prevent pump failures caused by internal corrosion. If there is a risk of frost, you mustn’t forget to drain the pump at the end of the day’s work. Whenever necessary, the complete sprinkler bar assembly can be removed quickly and easily with the help of the quick-change system.

Check whether the water nozzles are working properly every day. In the case of blocked nozzles or nozzles with an irregular spray pattern, it is advisable to replace them as soon as you have the time.

Driver & Service Kits

HAMM offers a number of kits designed to make maintenance and the replacement of parts much easier. These kits contain all the most important replacement parts.

Kits with genuine HAMM parts are particularly compact and take up very little space. This means that they can always be carried onboard the machine and allow, for example, the replacement of worn spray nozzles within just a couple of minutes.

Driver Kit

Sprinkling system parts

How to prevent wear affecting the sprinkling system

Use only clean water – this prevents clogging of water filters and unnecessary wear on pump and nozzles and ensures correct functioning of the sprinkling system at all times. Clean the filters in the sprinkling system at regular intervals to prevent premature pump failure. Nozzles blocked with asphalt residues should be cleaned or replaced as soon as possible.

Example of wear:

Intact nozzle

Blocked nozzle

Please note that unapproved water additives and / or separating agents can cause irreparable damage to the pump membrane and nozzles.

Tyres

There are several tyre types that differ in the way they look and the purposes for which they are used.


Tyres for compactors

Diamond tread tyres
  • Minimal tyre tracks
  • Less damage to the ground surface
  • Good traction for the majority of working scenarios
  • Poor traction on materials that rapidly damage tyre treads, e.g. abrasive materials
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EM-tread tyres
  • Good traction, above all on cohesive materials
  • Better self-cleaning
  • Distinct tyre tracks
  • Please note: tyres with a directional tread must be mounted correctly, mount in the recommended direction for best performance
  • Special heavy-duty tyres for the VC variant when used for rock crushing: extremely robust and resilient, resistant to sharp-edged materials
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Tractor tyres
  • Resistant to sharp-edged materials
  • Good rolling characteristics on hard and abrasive substrates
  • Increased durability
  • Poorer traction (above all on cohesive materials)
  • Non-directional tread
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Suitable for use on tandem and pneumatic tyre rollers

Smooth tyres
  • Smooth tyres for asphalt construction deliver the best compaction results
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Facts

Objectives of compaction

  • Reduction of voids
  • Improvement of load bearing properties
  • High longitudinal and transverse evenness
  • High initial grip
  • Maximum compaction result in the shortest possible time


Types of compaction

Static compaction

In the static compaction process, the applied load of the roller effects a shear stress in the layer to be compacted. However, compaction will take place only when the shear stress is approximate to the shear strength of the mixed material, i.e. whenever plastic deformation occurs. The individual mineral particles move and are rearranged in a more compact matrix. The proportion of voids is reduced and the stability increases.

Dynamic compaction

In the vibration and oscillation compaction process, the drum conducts vibratory energy into the asphalt layer in the form of a rapid succession of pulses. The individual particles of the asphalt layer are excited by these dynamic forces. This reduces the friction between the particles and enables them to be moved more easily into a favourable position for the creation of a more compact matrix.

  • Vibration compaction
    Conventional vibrating rollers have a circular vibrator inside the drum. Its fast rotation causes the drum to vibrate and conduct vertical forces into the ground. Vibration is suitable for almost every application in the fields of earthworks and asphalt construction. Today, it’s hard to imagine everyday work on the construction site without it and it yields the best compaction results.
  • Oscillation compaction
    Alongside vibration drums, HAMM also offers oscillation drums. In oscillation drums, the synchronous rotation of masses creates a moment centred on the drum axis. In the course of one revolution of the mass, the moment changes its effective direction (forward and backward), creating an oscillating motion of the drum that conducts shear forces into the ground.

Minimal vibration stresses for the surroundings

Oscillation generates significantly lower vibratory stresses. (see illustration, right). The stress levels it causes are only up to 10 per cent of those caused by vibration (see illustration, left). Oscillating drums do not use up their energy in the creation of undesired vibration in the surrounding area, but transmit it directly into the material to be compacted - precisely where the energy is needed. Minimised vibration guarantees a longer service life of the machine and provides optimal comfort for the operator.

The oscillation system developed by HAMM is not based on complicated mechanical control mechanisms, but relies entirely on the laws of physics. The amplitude value adapts automatically to the stiffness of the substrate. This means that the amplitude decreases continuously in inverse proportion to the increase of soil stiffness. The energy transferred into the soil therefore increases to the same extent as the amplitude decrease.

The following video illustrates the various different types of compaction:

The different drum types


Drum types – outer construction

  • Smooth drums
    With a smooth surface, smooth drums are primarily used for the construction of flat and even surfaces. Examples of this are asphalt surface layers or levelled surfaces in earthwork.
  • Padfoot drums
    Padfoot drums are used for earthwork and in cold recycling. This drum type kneads and roughens the ground. The padfeet enlarge the effective surface area of the ground to enable faster drying of moist ground. Padfoot drums are smooth drums with trapezoidal studs welded onto the surface of the drum.


Drum types - inner construction

  • Vibrating roller drums
    Rollers with smooth or padfoot drums for dynamic compaction featuring a centre shaft fitted with a vibrator system. This generates vibrations with the aid of imbalance masses attached to the shaft. In operation, the rotary vibrator generates and applies a vertical, sinusoidal force to the subsurface.
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  • Oscillation drums
    Up to four eccentric shafts (HD+ 120 and HD+ 140) with two imbalances each and phase shifted by 180°, rotate and create a forward-backward rotary motion of the drum. The drum maintains contact with the ground at all times. In many cases this type of dynamic compaction enables faster compaction of the road bed and the road surface and achieves higher degrees of compaction. Considerably less vibration stresses are created in the surroundings of the machine and the risks of particle crushing and over-compaction are minimised.
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  • VIO drums
    Depending on the positioning of the eccentric shafts relative to one another (in-phase or 180° phase-shifted), the compactor compacts the ground by means of vibration or oscillation. The frequency and amplitude of the front and rear drums can be individually adjusted to enable greater flexibility and increase compaction performance.
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