Rulmeca conveyor rollers for chain driven applications
Chain driven conveyor rollers are among the most flexible solutions for unit handling due to the availability of different configurations. On one hand, a continuous tangential chain or chain loop transmission system can be set up. On the other hand, the chain can drive rollers by means of pinions or crowns. The direct motion transmission from chain to rollers, driven by a geared motor, is suitable for countless material handling systems, excluding accumulation transport ones. Heavy, light, rugged, fragile, regular or irregular shaped goods or packages can be efficiently transported by chain driven conveyor rollers.
With its long and well-established expertise in design and production of material handling components, Rulmeca completes its wide range of rollers for unit handling conveyors with different series of chain driven conveyor rollers.
Chain loop or tangential transmission system
As the name suggests, chain loop transmission connects each roller to the following one through a chain ring. Its simple setting is opposed by higher costs and design constraints. First, its efficiency is lower and power absorption is higher. Secondly, conveyor length is limited and load capacity must be controlled because the chain-pull on the first loop directly connected to the gearmotor is incremental, as it is the sum of the chain-pull values of each roller. That’s why, whenever possible, central placement of gearmotor is recommended to reduce stress and overload on the chain and double conveyor length limit. However, chain loop driven conveyor rollers are highly employed in industry, ranging among manufacturing and processing, packaging and logistics applications, because they can perfectly support heavy load transportation on short distances and frequent start and stop cycles.
A more cost-efficient alternative is tangential transmission system where a continuous loop of chain runs underneath rollers, thus with less friction. Therefore, it’s recommended for light-medium loads handling on long distances. About that, conveyor length depends on chain resistance, therefore using a major pitch or a double chain allows for major length. A chain-guide profile, usually made of high-density molecular polyethylene, is needed to keep the chain in the exact position and ensure efficiency and noiselessness. The chain can slide either on the top or the bottom part of rollers. Between them, upper tangential chain requires particular attention to end rollers which are overloaded due to chain pull on the return angle. Therefore, the recommended position of gear motor is downstream or central (for reversible direction). Instead, it should be positioned on the starting end of the conveyor for lower tangential chain.
Crown or pinion sprocket driven conveyor rollers
Rulmeca selection includes two configurations of chain driven rollers: pinion and crown sprocket rollers, compatible with both tangential and chain loop transmission system. Pinion sprocket rollers have a pinion with one or two sprockets welded at the end of the tube. Their pitch diameter is lower than roller diameter, thus allowing for the containment of transmission overall dimensions below the roller plane. Despite its functional design, transmission ratio compromises chain-pull capacity. Unlike them, crown sprocket rollers have one or two crown sprockets welded on the tube. Therefore, here pitch diameter is higher than roller diameter, thus ensuring better transmission ratio and reducing chain-pull and stress of components.