Gib and Cotter Joint

grabcad

A gib and cotter joint is usually used in strap end (or big end) of a connecting rod. In such cases, when the cotter alone (i.e. without gib) is driven, the friction between its ends and the inside of the slots in the strap tends to cause the sides of the strap to spring open (or spread) outwards. In order to prevent this, gibs as shown, are used which hold together the ends of the strap.Moreover, gibs provide a larger bearing surface for the cotter to slide on, due to the increased holding power. Thus, the tendency of cotter to slacken back owing to friction is considerably decreased. The jib, also, enables parallel holes to be used.