This standard specifies the type, size, technical requirements, inspection rules, selection, marking and other requirements for the pup coupling of the mixing transmission device. This standard applies to the connection between the output shaft and the transmission shaft of the reducer of the mixing transmission device, and allows the space left by the coupling pup joint to be used for the lower half coupling without dismantling the reducer and frame. It is used for loading and unloading the machine, the intermediate bearing box of the frame and the transmission shaft sealing device.