Who has a lot of trees in his garden, Has bushes and hedges, you can hardly get past a chopper. But which shredding technology works best with bulky greenery? We name the strengths and weaknesses of the three chopper systems.
The goal is always the same: Branches, Branches and green garden waste, which arise constantly and can be wonderfully composted, should be so fast, be crushed thoroughly and quietly as possible. Choppers have quickly established themselves with garden owners, but the first models were very loud, often not that easy and safe to use and also quite expensive. But the manufacturers have come up with a lot: There are now over ten different shredding systems. All are based on three basic techniques, the hammer, Messer- and rolling mill. Everyone has plans- and disadvantages. That is why there are already combinations of hammer- and knife mechanism. With these combined shredders you can process any type of chopped material. A lot has happened, especially with regard to noise insulation: The new choppers have much better insulated housings and hoppers, so that neither engine nor cutting unit nor branches and twigs, which hit the inside of the funnel, cause extreme noise. The devices with a roller mechanism are referred to as quiet chopper, because they work at low speeds and crush the chopped material, instead of hacking it up. Most of these models have since been awarded the Blue Angel by the Federal Environment Agency, because they are quiet.
HAMMERWORKS
For everything coarse, chippers with a hammer mechanism are well suited. You don't just create branches and twigs, but also bulky perennial clippings with soil, Vegetable patch waste and sandy roots. Even nails and stones cannot harm it. The technology uses a simple principle: Movable metal sticks are attached to a rotating cylinder, with which the chopped material is hammered. This creates branches, leaves, Roots frayed so small, that they fit through a coarse-meshed metal sieve. advantage: The material is, so to speak, bite-sized for the microorganisms in the compost and rots faster. There are hammer mills with blunt and sharpened mallets. So that long branches and twigs can also be processed without any problems, many hammer mill choppers are equipped with an additional knife mechanism.
KNIFE WORKS
For all normal garden waste, which occur in small and medium-sized gardens, knife mechanisms are very suitable. There is also the greatest variety and selection here.
The simplest knife mechanism is a disc with at least two knives screwed on. Similar to a vegetable slicer in the kitchen, branches and twigs are cut into slices. Knife choppers of the older design were always particularly noisy, because the branches were caught in an uncontrolled manner by the knives and whirled around in the housing. The metal funnel was seldom soundproofed and only added to the noise. In modern knife choppers, this deficiency has largely been eliminated: Special counter knives prevent the loud, uncontrolled turbulence, and the effective insulation significantly reduces working noise. For this purpose, either relatively soft plastics were used for the housing and funnel or several layers of material were placed on top of one another (Sandwichbauweise). In addition, most knife choppers are now equipped with a self-closing mechanism, so that the chopped material no longer has to be pressed forcefully into the funnel as before. The new knife works have wings, Claws, Hook or double- or. three-story knife works, with which the material is packed and drawn in. Another variant is offered by devices with two independent knife mechanisms, which can be reached via two separate feed openings. Bulky shrubbery and shrub waste come into the wide funnel throat, the side, narrow opening is intended for smooth branches and twigs. In this way, the two knife units are only used for the material that is suitable for them and are therefore also protected.
The knife mechanism with the reversible direction of rotation also has the same effect. All soft is cut to the left, on the right everything hard comes under the knife. The spiral or worm knife is also designed in this way, that the branches can be reliably held in the factory and cut off smoothly. The fresher the tree- or hedge trimming, the better, especially the less powerful models work. For very hard, Dried wood needs a strong chopper (away 2000 Watt power consumption). Yet, the great disadvantage of all knife works has remained: their sensitivity to hard foreign bodies. So can nails, Screws, wire, Sand and earth make the knives unusable in a short time. Have the knives become dull through normal use?, is that not a problem. All manufacturers offer replacement blades. Most devices can even be assembled by yourself. Most of the time you only need a screwdriver. Only a few garden shredders have to go to the manufacturer's customer service department for a knife change. Some knife works have reversible knives, which practically have twice the service life.
ROLLING MILLS
When the working noise when chopping should be as low as possible, only the roller mill comes into question. It only rotates about forty times a minute and does not generate any vibration. Like a small water mill wheel, it turns slowly and takes the clippings with it between its sharp teeth, that is pressed against a metal plate and crushed. As with hammer mills, the chopped material is then ideal for composting. Very pleasant: Has become in
Cutting unit wedged a branch, you can reverse the direction of rotation of the roller. Blockages can be cleared within seconds.
Similar to the knife works, the cylinder knives also work most effectively, when the cut surfaces are sharp. Because the working speed of roller choppers is relatively low, they are only suitable for gardens with little green cuttings. Also, the funnel opening is so narrow for safety reasons, that only a few branches can be inserted at a time. Under no circumstances are allowed to earth, Sand, Stones or metal parts get into the cutting unit. In a short time, the results would no longer be acceptable. Roller choppers are compact and relatively light. Therefore, they are ideal for transport in the car. To everyone's delight, who do not yet have their own shredder.