6. Large Pitch Conveyor Chains
6.1 WHAT IS LARGE PITCH CONVEYOR CHAIN? Large pitch conveyor chains (Figure 6.1) are big pitch chains with rollers, originally based on cast iron chains. The base material was changed to steel, and they incorporated some of the features of drive chains and small pitch conveyor chains. They were standardized by Tsubaki in the 1920s. They were developed in Japan as millimeter-unit pitch chains, available in a variety of pitches for a given capacity. Similar chains are available in the United States, but are usually measured in inch-unit pitch. 6.1.1 Standards ISO 1977/1 ~ 3 includes standards for large pitch conveyor chains. These standards are for European-type chains, which have larger diameter bushings, pins, and rollers, and thinner, taller side plates than comparable sizes of chains made in the United States or in Japan. Japan Chain Industry Association Standard JCAS 2-1982 governs seven cate- gories of large pitch conveyor chains. The major characteristics of these cate- gories are shown in Table 6.1.
Table 6.1 Major Characteristics of Large Pitch Conveyor Chain
Chain
Tensile Strength
Side Plate
Inner Link
Roller Diameter
Number (Pin Dia.)
Pitch (mm)
(kN)
Height Thickness Width
Small
Large
08 11 14 16 19 22 25
29.4 68.6
75 ; 150 75 ; 150 100 ; 200 150 ; 300 150 ; 300 200 ; 450 250 ; 600
23 33 39 46 52 66 81
3.2 4.7 6.3 8.0 9.5 9.5
15.7 20.7 28.7 35.8 50.1 55.9 65.4
15.9 22.2 29.0 34.9 40.1 44.5 50.8
32 40 50 65 80
107.9 176.5 205.9 274.6 470.7
100 125
12.7
6.1.2 Nomenclature Some chain manufacturers use their own nomenclature. In the case of Tsubaki, for example, chain size 16 with 200 mm pitch, is listed as RF12200-R. Here’s what that name means.
RF 12 200 - R
Average tensile strength, in tons, of the chain when it was originally designed
Chain pitch Roller type
There are larger sizes than those shown in Table 6.1; in fact, tensile strength can exceed 4,460 kN! If you need extra-high performance chain, discuss the options with the manufacturer.
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