screenshot-2021-07-09-23-50-50-72-cdd6b75f7010e559fcf0928143af0929

A gib and cotter joint is usually used in strap end (or big end) of a connecting rod as shown in Fig. 1. 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 as shown dotted in Fig. 4 (a). In order to prevent this, gibs as shown in Fig. 4 (b) and (c), are used which hold together the ends of the strap.