What is Leaf Chain?

What is Leaf Chain?

Leaf chain only consists of link plates and pins which is the simplest steel chains.

It is commonly used on forklift trucks, telehandlers and in other material handling applications.

As the link plate found on the standard roller chain, the link plate of leaf chain also has the same figure of 8 shape.

Leaf chain is also called balance chain and cable chain.

Comparison of Leaf chain and Roller chain

Chain Type	Components				Running Over (genereally)	Application
	Plate	Pin	Bush	Roller
Roller chain	1. Outer plate 2. Inner plate	✔	✔	✔	sprocket	Any kind of Industrial machines
Leaf chain	1. Outer plate 2. Inner plate	✔	X	X	Sheaves	Forklift Telehandler Other matierial handling

Leaf Chain Construction

Roller Chain Construction

Extended Reading

• What is Roller Chain?

What are the types of Leaf chain?

Standard roller chains can be categorized into American type and European type.

Leaf chain also has the same distinction.

There are three main types of leaf chain series.

• AL series have the same plate thickness and pin diameter as the ANSI standard roller chain of same pitch.
  E.g., under the same pitch of 1/2”, ANSI 40 and AL4 have the same plate thickness and pin diameter.
  AL series are commonly used for light load application.

• BL (LH) series is constructed of thicker plates and larger pins than AL series of the same pitch.
  The plate thickness and pin diameter are the same as the ANSI standard roller chain with a pitch one size larger.
  E.g., BL4 has the pitch 1/2” which is same as the ANSI 40 but the plate thickness and pin diameter are the same as the ANSI 50.
  BL series are commonly used for heavy load application.
  

• LL (EL) series are made to ISO standards so they have the same plate thickness and pin diameter as the British standard roller chain.
  E.g., under the same pitch of 5/8”, 10B and LL10(EL5) have the same plate thickness and pin diameter.
  LL(EL) series are commonly used for light load application.
  

Series	Type	Leaf chain v.s. Roller chain (Compared under the same pitch)		Application
		Link Plate	Pin
AL	American	same thickness as the ANSI roller chain	same diameter as the ANSI roller chain	light load
BL(LH)	American	Same thickness as the ANSI roller chain with a pitch one size larger	Same diameter as the ANSI roller chain with a pitch one size larger	heavy load
LL(EL)	European	same thickness as the British roller chain	same diameter as the British roller chain	light load

Leaf chain lacing combination

The lacing combination of standard leaf chain can be from the smallest 2x2 lacing to the largest 8x8 lacing.
The first digit refers to the quantity of the outer plate and the second digit refers to the quantity of the inner plate.
The following photos will help you to understand.

How to identify leaf chain part number?

From the above, we have learned the types of leaf chain and the lacing combination. These are also a part that forms to the leaf chain part number. Let us take some examples as the following.

The first two letters refer to the leaf chain series.

The last two numbers refer to the plate lacing.

The numbers in the middle (can be one or two digits) refer to the chain pitch code.

Part Number	Series	Pitch Code	Lacing
AL422	AL	4	2X2
AL1022	AL	10	2X2
BL588	BL	5	8X8
BL1666	BL	16	6X6
EL844	EL	8	4X4
EL1644	EL	16	4X4

However, the pitch code doesn’t directly refer to what pitch it is.

The unit of pitch is usually expressed as inch and the pitch codes only refer to the numerator of the fraction in inches.

They have the rules as following.

• AL series: It is measured in 1/8 inches so the denominator of the fraction refers to 8 and the numerator of the fraction refers to the pitch code.

• BL (LH) series: BL is the chain number stipulated by ASME B29.8 while LH is stipulated by ISO 4347.
  Both are the same chain but has different expression on the pitch.

• BL is measured in 1/8 inches, same as AL series. The numerator of the fraction also refers to the pitch code.
• LH is measured in 1/16 inches so the denominator of the fraction refers to 16 and the numerator of the fraction refers to the pitch code.

From the above, we will get the result as following.

• LL (EL) series: LL is the chain number stipulated by ISO 4347 but they also be named as EL by some manufacturers. Both are the same chain but has different expression on the pitch.
• LL is measured in 1/16 inches, same as LH series.
  The numerator of the fraction also refers to the pitch code.

• EL is measured in 1/8 inches, same as AL/BL series.
  The numerator of the fraction also refers to the pitch code.
  

From the above, we will get the result as following.

Series	Numerator	Denominator	Example
			Part number	Pitch in inch	Pitch in mm
AL	refer to the middle number	8	AL422	4/8 = 1/2	12.7
			AL1022	10/8 = 1-1/4	31.75
BL(LH)		8 (BL) 16 (LH)	BL588	5/8	15.875
			LH1088	10/16 = 5/8	15.875
EL(LL)		8 (BL) 16 (LH)	EL1644	16/8 = 2	50.8
			LL3244	32/16 = 2	50.8

※ 1 inch = 25.4 mm