Machinery's Handbook, 31st Edition
Transmission Roller Chains 2619 Chain Pitch: Distance in inches between centers of adjacent joint members. Other di- mensions are proportional to the pitch. Tolerances for Chain Length: New chains, under standard measuring load, must not be underlength. Overlength tolerance is 0.001/(pitch in inches) 2 + 0.015 inch per foot. Length measurements are to be taken over a length of at least 12 inches. Measuring Load: The load in pounds under which a chain should be measured for length. It is equal to 1 percent of the ultimate tensile strength, with a minimum of 18 pounds and a maximum of 1000 pounds for both single and multiple-strand chain. Minimum Ultimate Tensile Strength: For single-strand chain, equal to or greater than 12,500 × (pitch in inches) 2 pounds. The minimum tensile strength or breaking strength of a multiple-strand chain is equal to that of a single-strand chain multiplied by the number of strands. Minimum ultimate tensile strength is indicative only of the tensile strength quality of the chain, not the maximum load that can be applied. Standard Roller Chain Numbers.— The right-hand figure in the chain number is zero for roller chains of the usual proportions, 1 for a lightweight chain, and 5 for a rollerless bushing chain. The numbers to the left of the right-hand figure denote the number of 1 ⁄ 8 inches in the pitch. The letter H following the chain number denotes the heavy series; thus the number 80 H denotes a 1-inch pitch heavy chain. The hyphenated number 2 suf- fixed to the chain number denotes a double strand, 3 a triple strand, 4 a quadruple strand chain and so on. Heavy Series: These chains, made in 3 ⁄ 4 -inch and larger pitches, have thicker link plates than those of the regular standard. Their value is only in the acceptance of higher loads at lower speeds. Light-weight Machinery Chain: This chain is designated as No. 41. It is 1 ⁄ 2 inch pitch; 1 ⁄ 4 inch wide; has 0.306-inch diameter rollers and a 0.141-inch pin diameter. The minimum ultimate tensile strength is 1500 pounds. Multiple-strand Chain: This is essentially an assembly of two or more single-strand chains placed side by side with pins that extend through the entire width to maintain align ment of the different strands. Types of Sprockets.— Four different designs or types of roller-chain sprockets are shown by the sectional views, Fig. 1. Type A is a plain plate; type B has a hub on one side only; type C , a hub on both sides; and type D , a detachable hub. Also used are shear pin and slip clutch sprockets designed to prevent damage to the drive or to other equipment caused by overloads or stalling.
A
B
C
D
Fig. 1. Types of Sprockets
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