PUMP ACTUATION LEVERS
ADJUSTMENT NUT
HYDRAULIC PUMP
HTH — MAINTENANCE
There are some things to look for when checking to see if adjustment is necessary. Is the machine wearing out blades unevenly (i.e. one blade is completely worn out while the oth- ers look new)? Does the machine have a perceptible rolling or bouncing motion when in use? Look at the machine while it is running, do the guard rings “rock up and down” relative to the ground? Do the pitch control towers rock back and forth? These are some of the indications that the blade pitch may need to be adjusted using the adjustment bolts on the trowel blade finger.
Figure 16. Pump Actuation
Levers/Speed Control Rod
Matching Blade Pitch for Both Sets of Blades
Sometimes it may be necessary to match blade pitch between the two sets of blades. There are some signs that this may be necessary. For example, the differences in pitch could cause a noticeable difference in finish quality between the two sets of blades. Or, the difference in blade pitch could make the machine difficult to control.This is due to the surface area in contact with the concrete (the blade set with the greater contact area tends to stick to the concrete more).
To fix this problem, each spider assembly can be pitched indi- vidually. With a Single Pitch machine, the operator is forced to constantly make adjustments on each pitch tower. On a Twin Pitch machine, the operator must lift up on one of the pitch control handles, disengaging the linkage between the towers. Once this is done, a pitch control crank can be turned to adjust the difference. Make sure to lock the linkage back in place when finished with adjustments.
Blade Pitch Adjustment Procedure
The maintenance adjustment of blade pitch is an adjustment that is made by a bolt (Figure 17) on the arm of the trowel blade finger. This bolt is the contact point of the trowel arm to the lower wear plate on the thrust collar. The goal of adjustment is to promote consistent blade pitch and finishing quality.
Figure 17. Blade Pitch Adjustment Bolt
The easiest and most consistent way to make this adjustment is to use the Trowel Arm Adjustment Fixture (P.N. 9177) that is manufactured by Whiteman. This fixture will allow consistent adjustment of the trowel arm fingers. It comes with all the hardware necessary to properly accomplish this maintenance and instructions on how to properly utilize this tool. Adjusting the trowel arm fingers without a fixture requires a special talent.
If a trowel arm adjustment fixture is not available and immediate adjustment is necessary; we suggest the following procedure. If you can see or feel which blade is pulling harder, adjust the bolt that corresponds to that blade. Another way to determine which blades need adjustment is to place the machine on a flat surface and pitch the blades as flat as possible. Now, look at the adjustment bolts.They should all barely make contact with the lower wear plate on the spider. If you can see that one of them is not making contact; some adjustment will be necessary.
It will be possible to adjust the “high” bolts down to the level of the one that is not touching, or adjust the “low” bolt up to the level of the higher ones. If possible, adjust the low bolt up to the level of the rest of the bolts.This is the fastest way, but may not always work. Verify that after adjustment, the blades pitch correctly. Often times, if the blades are incorrectly adjusted, they will not be able to pitch flat.This occurs when the adjusting bolts have been raised too high. Conversely, sometimes the adjusting bolts are too low and the blades cannot be pitched high enough for finishing operations.
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