There are several possible causes all of which could be examined if there was some information available. ■

Short, but to the point John! ■

Dan

What are the details???

Did the bearing collapse and then eh shaft bear on the brg housing

Pls check the load capacity of the bearing housing - sold base, hollow base and material.

Check this against the load.

Thanks

James ■

Perhaps the drive side is significant. Pillow blocks suggest the shaft is mounted over a beam. That beam deflection fluctuates continually. If your housing is cast iron a fatigue failure will be possible. Greater weight carried on the drive side would contribute to the failure there. K-brace the beam & see how it goes.

For reference; some pyrometallurgy works ban cast iron gearbox housings because of past cold shortness failures encountered when the support beam hogs under no load situations. These were one off loads, admittedly, but the beam mounting in their case & yours is worth looking at.

Now can we have some more information? Or we'll get technical! ■

Dear Mr. Dan,

You can look for following points :

1) Check the load being imposed on bearing. This would be sum of the carrying side weight return side weight and scooping forces.

2) Check the adequacy of the bearing / plummer block with respect to this load. The bearing (and thereby also plummer block) could be underrated with respect to actual load. In case of elevator, the plummer block will be subjected to only downward load. It is presumed that the plummer block base is horizontal. Otherwise one has to check the load carrying capacity of plummer block with respect to the direction of load.

3) Necessary stiffness of shaft.

4) The possibility of misaligned installation of drive shaft with respect to drive unit. This could be one of the important reasons for bearing / plummer block failure on drive side. Also, check the stiffness of platform portion supporting the drive unit. If this portion is not adequately stiff then the drive shaft and thereby the bearing would be subjected to radially oscillating load in tune with the amplitude of platform / drive.

5) Possibility of faulty / defective plummer block.

You have not mentioned whether drive unit is transmitting power to drive shaft through flexible coupling or chain drive. If it is chain drive, then the issue mentioned in serial no. 4 will not be prominent.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

Did the conveyor JAM or fail prior to problem? ■

George - I wonder if he has any roller chain or sprockets left-ouch!!!!! ■