GCLD type drum gear type coupling belongs to rigid flexible coupling. Gear type coupling is composed of inner gear ring with same number of teeth and flange half coupling with outer teeth. Divided into straight teeth and drum tooth outside two kinds of tooth shape, tooth is the so-called drum will made spherical outer teeth, spherical center on the gear axis, backlash is generally large gear, drum gear couplings allows a larger angular displacement (as opposed to straight tooth coupling), can improve the tooth contact conditions, improve the ability to transfer torque, prolong service life. The contact state along the tooth width when angular displacement is present. Radial, axial and angular axis deviation compensation ability, has a compact structure, small turning radius, large carrying capacity, high transmission efficiency, low noise and long maintenance cycle, especially suitable for the condition of low speed and heavy loading, such as metallurgy, mining, lifting transportation and other industries, can also be applied to petroleum, chemical industry, general machinery and other kinds of shaft transmission of machine.