The coupler couldn't have the oblique axial lead and the radial displacement beyond the regulations to avoid influencing its transmission performance. 

After the installation and normal operation of coupler for one shift, all fastening screws must be inspected. If they are loose, they must be tightened again with the tightening torque as specified for several repeated shifts to guarantee the tightening. 

The coupler's sliding surface, crosshead, bearing, etc. must be lubricated by adopting the 2# industrial lithium base grease or 2# molybdenum disulphide calcium grease. They are fueled every 500 hours with continuous running and are fueled every 2 months with intermittent running. If the fuel must be added every week at high temperature, the oil hole screw on the bearing face is unscrewed upon oil filling and the oil is injected with the high-pressure oil gun till the oil spillage. 

In the daily maintenance of coupler, the indentation and other normal wear phenomenon shall be promptly replaced once found. The crack isn't allowed in the coupler. Otherwise, the coupler shall be replaced (knock with small hammer and judge as per the sound); The cross axle is turned for 180° upon the maintenance and unpicking and washing to reach the alternate use of axial neck due to the stress. 

The tooth width contact length of gear coupler shall not be less than 70%; Its axial movement shall not be more than 5mm. 

For the tooth thickness wear, the gear coupler shall be scrapped when the lifting mechanism exceeds 15% of the original tooth thickness and the running mechanism exceeds 25% as well as there is the tooth break. 

The elastic ring of pin coupler and the sealing ring of gear coupling shall be promptly replaced in case of the damage and aging. 

In the work operation, we shall often observe whether the universal coupler has the abnormal radial swing and bearing heating, etc. We shall promptly maintain the universal coupler if any