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Gall chains DIN 8150 in stock!
25.8.2017 09:42:56

Wide range of Gall chain DIN 8150 in stock. more

Bush chains DIN 8164 in stock!
25.8.2017 09:41:20

We have expanded our stock of bush chains. more

Toothed Roller Chain 16B1 in our Stock
11.6.2012 08:15:27

Due to increased interest and demand, we also have the toothed-roller chains as part of our regular warehouse inventory. These chains are predominantly destined for the wood processing industry. more

Fast Contact

KD TRANSPORT, spol. s r.o.
MORAVIAN CHAINS
U Ambulatoria, 772 00 Olomouc
Czech Republic
Phone: 00420 585 359 039
Fax: 00420 585 359 040
E-mail: info@mch-retezy.cz

Chain Installation

Axial Distance and Sagging of Chain

The recommended axial distance is 40 times the chain pitch; the usual considered maximum being 160 times the chain pitch. For smooth operation the chain is required to be correctly pre-stretched, either by setting the sag rate of the free strand or by using a tension pulley. The chain sag should be so adjusted that the free strand shows minimum sag of 1% and maximum sag of 3% of the axial distance. When a tension pulley is used, this should be so placed after the driving chain wheel that the stretching force acts against the chain sag. The magnitude of the stretching force should reach 1% of the breaking load. The pulley should allow for a tension rate of 2.5 times the chain pitch. In this case the use of an offset link, which reduces the permissible load by up to 30%, should be avoided. Horizontal or sloped arrangements of a chain drive with the lower strand unloaded present a good solution. Less suitable is a vertical arrangement. A horizontal arrangement with the upper chain strand unloaded is an absolutely poor solution and should be avoided. The chain wheel shaft should always be positioned horizontally. When in operation, the chain should neither be pushed forward nor be exposed to any lateral force. The operating load causes a steady extension of the chain which should not exceed 2%. Otherwise the chain wheels will be subjected to excessive wear.

Chain Drives

Requirements for Assembly and Maintenance of Transmission Gear

  • When constructing a transmission gear, care should be taken to ensure that the upper chain strand exercises the pulling function while the lower strand is free.
  • The chain must approach the chain wheel freely.
  • Tension pulley, if any, must be installed after the driving (small) wheel and should have an odd number of teeth while its engagement should cover at least 3 teeth.
  • If no tension pulley is used, the chain should have its lower strand slightly sagged, the sag must, however, not exceed 3% (see "Axial Distance and Chain Sag").
  • A chain too tightened exerts excessive load on the bearings, features greater resistance, causes faster wear of the chain wheels and its service life is compromised. On the contrary, a chain that is too slack causes, through its oscillations, an unstable run and in extreme cases the chain can even fall off the transmission gear.
  • Where large axial distances are in question (of more than 60 times the pitch) the free chain strand should be supported by a pulley or a guide gib.
  • Where vibrations occur on the tensioning assembly a vibration damper should be provided.
  • The chain should not be pushed, twisted or exposed to lateral forces.
  • In an application, the chain should not be extended by more than 2% or by more than 1% in case of high speed chains.
  • The jointing and driving links are exposed to increased stress resulting in higher wear rate. During operation these chain elements should therefore be checked at regular time intervals.
  • Chain wheels must not show any peripheral and, in particular, frontal run-out. The chain wheel design for roller and bush chains should be in line with the standard specifications (DIN 8192, DIN 8196, and ČSN 01 4811).
  • The maximum permissible axial mismatch or error in parallelism of the chain wheels in the plate is 3 per mil, i.e.3 mm/m.
  • By reason of the driving force distribution onto a larger number of chain wheel teeth, the girdle angle of the driving wheel should be 120° as a minimum and at least 90° in the case of larger driving wheels (having more than 25 teeth).

Chain Run-In

The new chain in the operation features settlement of the pressed joints for some time after installation. As this feature causes a slight increase in the clearance between the individual chain elements in the direction of the force action, the chain should be checked up on during the run- in period with regard to a possible excessive enlargement in the sag of the free chain strand. In view of their shorter run-in period, roller chains are pre-stretched after manufacture. In the case of a new chain being mounted on a chain wheel with a large number of teeth (more than 60 teeth) the chain may be required to be pushed onto the wheel teeth by force. The seeming reduction of the chain link pitch is caused by the lubricating grease filling the gaps between the roller, bush and pin. After some turns of the chain wheel the grease will be forced out and the chain will settle into the grooves.

Chains Storage

The chains should be well preserved and stored in a dry and well-ventilated place having a relative humidity of 54% to 75%. The store should be sealed off from admission of gases and dust. No chemicals are permitted to be stored together with the chains (see ČSN 02 3301, Art.44). The recommended storage temperature is between +5°C up to +40 °C.


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