2.3.4 Strength of Attachments
Bending and twisting forces can affect the attachments. For the A attachment, which is a common type, the allowable load calculation indicated in catalogs is based on the bending strength.
When a tall fixture is added onto the attachment, you must study the strength of the entire configuration. When the attachment is subject to forces other than those explained, you also must calculate the twisting forces. If the attachment receives bending forces at the same time, make sure to combine the bending forces with the twisting forces.
When calculating the strength of attachments such as A-type, K-type, SA-type, and SK-type, which are extensions of a standard steel chain's plate, use the values shown below as their ultimate tensile strength, and choose a proper safety factor.
Nonheat-treated plate: 490 MPa (50 kgf/mm2)
Heat-treated plate: 1,078 MPa (110 kgf/mm2)