PAGE 38 — MAYCO C30HDGA CONCRETE PUMP • OPERATION MANUAL — REV. #1 (09/09/19)
MAINTENANCE
DRIVE CHAIN LUBRICATION
As a chain articulates in entering and leaving a sprocket,
there is relative movement between pin and bushing
surfaces. These surfaces wear causing chain elongation.
If a lubricant film can be maintained between the pin and
bushing, the wear rate is very slow and the chain wear
life very long. Maintaining the oil film is relatively simple
at low speeds but becomes increasingly difficult as the
speed increases.
It is recognized that good lubrication is not possible in
many applications, so shorter wear life must be accepted
in these situations.
In general, chain wear leads to rough or unsatisfactory
service prior to actual chain breakage. Good lubrication
can help to prevent chain failure by providing protection
against rust or corrosion. Rusting can allow pits to form in
the surfaces of the chain parts causing stress concentration
points. This can lead to chain failure at relatively low loads.
The clearance between pin and bushings is very small
(Figure 29), on the order of .003 to .005 inches. A lubricant
must be thin enough to flow into the chain. SAE 30 weight
oil is about right for room temperature. Lighter oil should be
used for lower ambients and heavier for higher operating
temperatures. Grease should not be used as it cannot
penetrate chain clearances
Figure 29. Chain-Link Cross Section
