5. Free Flow Chains
Table 5.2 Outboard Roller Chain (Side Roller)
RS Attachment Type
RF Double Pitch Type
Engineered Plastic Roller
RS40~100
RF2040~RF2100
Electroconductive Plastic Roller
RS40~60
RF2040~RF2060 RF2040~RF2160
Steel Roller
RS40~160
type, side rollers cannot be installed on every pitch on the same side of the chain. They can be installed on every pitch in alternating positions (Figure 5.11). In RF-type, the diameter and width of the side roller are different for S-rollers and R-rollers. When the stopper in a free flow conveyor is released, pallets accelerate to the chain speed. This acceleration is determined by the coefficient of friction between the side roller and the pin. The smaller the coefficient of friction, the longer it takes for the pallets to reach the speed of the chain. Faster accelera- tion can be accomplished by installing brake rollers. The construction and coefficient of friction of the brake rollers are different for each chain manufac- turer. In engineered plastic side roller products from Tsubaki, the coefficients of friction of chain are: with brake, 0.10; without brake, about 0.06. Selection and Handling Outboard Roller Chain has the following characteristics compared to DOUBLE PLUS ® Chain: (1) Greater allowable tension for the carbon steel chain (Table 5.3). (2) More economical. RF2050 chain costs about half as much, and sprockets cost about two-thirds that of the equivalent size of DOUBLE PLUS Chain. (3) More noise. Comparing systems with the same pallet speed and sprock- ets with the same number of teeth, Side Roller Chain emits about 10 to 15 dB(A) more noise than DOUBLE PLUS Chain. (4) Because the body of Side Roller Chain is exposed over the guide rail, this chain does not have the same safety features as DOUBLE PLUS. (5) Snap covers are not available for Side Roller Chain. It is difficult to prevent small objects from falling in between chain components. (6) Complete kits for Outboard Roller Chain, including the guide rails and other components, are not available. Therefore, you have to create your own system.
Table 5.3 Allowable Tension of DOUBLE PLUS ® and Outboard Roller Chains Chain Type Roller Type RF2040 RF2050
RF2060
RF2080
DOUBLE PLUS ®
Regular Series
0.88 0.44 2.65 0.44
1.37 0.69 4.31 0.69
2.06 1.03 6.27 1.03
5.29 2.65
Chain
High Friction Series
Outboard Roller
Steel Roller
10.7
Chain
Plastic Roller
1.76
(Allowable load kN)
185
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