FAQ

The material is stabilized against ultraviolet rays. ROLL-RINGS in general machine building are stabilized against solar radiation related to a 4 years round-the-clock driving. Some test samples broke down because their surface became tears by a maximum springing. Weathering tests could positively demonstrate stabilization. ROLL-RINGS in agricultural machines got twice the stabilization and will be stabilized for at least 8 years.

We haven’t investigated yet if the ultraviolet stabilizer also protects from radiation. Test results show that radiation might cause growing tensile strenght and breaking stretch as well as the modul of elasticity goes down a little. We can conclude that ROLL-RINGS exposed of radiation can be used at least in slowly moving chain drives . But specific tests are necessary.

The material has got a high level of hydrolysis stability. We suggest “impregnating” the adjusters with a chain lubricant for O-RING-CHAINS. There is a good stability in damp-hot surrounding.

ROLL-RINGS are tested at the chain speeds in the temperature ranges and at a maximum spring way as shown in our product list. There are reserve supplies which have to be estimated from case to case depending on chain speed, starting pushes and spring ways.

The material is extraordinary resistant to oils and hydraulic liquids. At room temperature it is also quite resistant to acids and bases. But there are bounds for non- stop running in chemicals at temperatures over 60 °C.

The material doesn’t change chemically under vacuum conditions. But it must be considered that under a 100% vacuum!!! forming heat can’t be abducted and tensioners are expected to break down.

Our material is resistant to abrasive substances if the gear section is protected by lubricants. This is the case, if the chain is lubricated.

The material is a high-capacity elastomere. It consists of a hard-flexible framework ( you could imagine as a model of wire) and in this framework are stored soft and medium elastic isles, which hold hydraulic position when ROLL-RINGS roll at adequate temperatures and revolutions. When chain drives are started in the cold or operating temperatures get higher the pushing and pulling elasticity modules of the soft, medium and hard components vary . As a result there are different elasticity and dampening.
How to mix the material is technical know how of the EBERT company.

Forming of ROLL-RINGS have got three components: elastic, viscous-elastic and plastic one. The elastic component determines tension and maximum way of the spring in non stop running. ROLL-RINGS are constructed in the way that the forming takes place in the elastic range only. The viscous- elastic component determines parts of tensioning and of maximum way of the spring. From the practical view, the plastic component in the ROLL-RING has got a secondary meaning only as well as in the timing belt. Because of these kinematic conditions we have introduced limits of safe load for ROLL-RINGS. Without any security risk you can drive our tensioners up to the limits. May be you could overstep these limits if you proved special working conditions. We recommend to ask your questions by using our free fax- or mail service.

After statistic analysis we ‘ve preferably chosen 19 teeth ( mechanical engineering) and 17 teeth (agricultural machines) for ROLL-RINGS. The most frequent number of teeth is T=30. We’ve introduced T=26 and T=34 for dispersion ranges. “Smaller” ROLL-RINGS are especially interesting for chain drives in assemblies.

The life time of ROLL-RI NG chain adjusters as life of any other technical system depends on its stressing. As an example to give you we would like to mention that one ROLL-RING of type 10803001 was exposed 72 million revolutions in a test chain drive. At the same time 2 roller chains were worn out. The loss of tension was 5% only. Transferred to a conveying chain drive that works at a speed of 0,38 metres per hour that means 20 000 hours of life. The data on our list of articles mean, that the life time of the ROLL-RING is longer than the life time of the chain, if these conditions are given.