Troubleshooter
Deck Crane slewing gear ring
A good maintained crane slewing gear ring it can be seen from afar.
Before climbing on the crane , first thing I do is to check the condition of the crane from outside. When the outside surface below the slewing gear ring is clean then the ring is at risk. The outside area of a proper maintained ring has to be with visible trace of grease.
There are 2 types of slewing bearings: with balls and with rollers. And is either bolted or welded to the pedestal and rotating platform of the crane.
Slewing bearing with rollers is used for smaller cranes up to 30 tones and the bearing with balls is for bigger type of cranes.
Measurements should be taken regularly to overtake the wear over the slewing ring.
The wear in the bearing may be checked by taking periodic grease sample.
The grease sample should be taken properly.
Follow this:
– Clean the areas where the sample will be taken.
– Push new grease into the grease point and collect the first used grease which will come out at the seal.
All the time a struggle to take grease sample. It is a complicated procedure because of the narrower space between the bearing and crane platform. Find proper tools, check the drawings for location and dimension of the grease point and prepare to make an effort to take sample of grease.
I would say that at least 2 points selected to obtain a sufficient grease sample. One sample taken in the area under jib and one sample 180° in opposite direction.
For a piece of mind, follow these basic rules for proper lubrication of the slewing bearing:
- Use the recommended grease;
2. Check the manual of the crane for location and dimension of the grease point;
3. Follow the maintenance and lubricating chart inside the crane manual;
4. Heavily grease until overlap of greasing is achieved and the whole bearing circumference is filled with new grease.
