Tool bushings
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Lower bush Function
Used to guide the tool correctly. It is located at the very exit of the tool from the hammer and is subject to strong wear, hits of stone, etc.
Maintenance
Regular and proper lubrication is very important. It is recommended to remove the tool once a week and visually inspect the condition of the bushing. Depending on the type of hammer, the bush must not be worn out more than 3-6 mm (difference between the outer diameter of the tool and the inner diameter of the bush)
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Upper bush Function
Used to guide the tool correctly. It is located above the lower bush in the upper part of the chuck housing and guides the tool in the upper part.
Maintenance
Regular and proper lubrication is very important. It is recommended to remove the tool once a week and visually inspect the condition of the bush. Usually, the upper bush is changed every 2 replacements of the lower bush. Replacing only the lower bushing with the used upper bushing very quickly leads to breakage of the tool and sometimes damage to the piston. |
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Stop ring (spacer ring)Function
Its main function is to stop the tool, which bounces off the surface/rock and tries to "penetrate" into the hammer. The tool stops at this ring. All tools have a bevel on the part that strikes this ring. Therefore, the stop ring must have the same slope in order for the tool to fit properly on the impact part of the ring.
Maintenance
Very often users and even inexperienced service technicians neglect this ring and do not change it regularly. A faulty stop ring is a very common cause of tool fractures in the inner part whose pieces can seriously damage the piston and cylinder. This ring must be replaced by replacing the upper bush! Worn out tools can seriously damage this ring. Cheap tools can have a wrong slope and damage this ring as well as the piston! |
Combi bush Funkcija
The combined bushing (in one piece we find the lower bushing, the upper bushing and the stop ring) is found in some models of small hammers. It has a long guide of the working tool, which significantly extends the service life of the tool and reduces the possibility of tool breakage. The lower (outer) part is subject to higher wear.
Maintenance
Regular and proper lubrication is very important. It is recommended to remove the tool once a week and visually inspect the condition of the combi bush. Depending on the type of hammer, the combi bush must not be worn out more than 3-6 mm (the difference between the outer diameter of the tool and the inner diameter of the combi bush). They have a longer lifespan than standard three-piece bushings but are more expensive.
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Spacer bush
Function
This is a design in which the upper bush and the stop ring are made in one piece. It combines the characteristics of the upper bushing and the stop ring.
Maintenance
A faulty spacer bush is a very common cause of tool fractures in the inner part whose pieces can seriously damage the piston and cylinder. This bushing is usually replaced with every other replacement of the lower bushing! Worn out tools can seriously damage spacer bush. Inexpensive working tools can have a wrong slope and damage the stop ring as well as the piston!
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Stopping the working tools in a spacer bush or spacer ring, guiding the tools in bushings