Bull gear

Single geared, single drive (SGSED) motor flywheel, one pinion gear, and bull gears on main shaft. 

Crankshafts Camshafts Clutchshafts Intermediate shafts Bull gears Flywheels Pinion gears... 

One of the great advances for maintenance on bull gears has been the use of locking rings, which eliminate keys and keyways. When you have a bull gear which requires the bore or key way to be repaired, ask your vendor if a locking ring can be used. If so, do it because no more keys will have to be made and fitted, and this will eliminate some of your maintenance. 

Approximately one-fourth of all operating presses in the United States have a mechanical-type clutch (full revolution) which presents difficult and costly safety and maintenance repairs. If a mechanical clutch on a press is clicking while the flywheel or the bull gear is rotating, this indicates a potential problem. Immediate repairs should be made to safeguard the press operators. If not, the clutch pin may drop in, causing an unintended press cycle with possibly disastrous results. 

Defects such as clutch, bull gear or drum-cheek casting cracks can be difficult to assess and repair. The cracks could be stable foundry cracks or unstable fatigue cracks, and it can be difficult to differentiate between the two defects. Repairing cracks in castings requires specialized facilities and experience that is not always readily available. 

Regrind main shaft seats, re-cut clutch teeth, re-cut bull-gear and pinion teeth, turn brake path on drum, weid repairs, sleeve or oversize ovai hoies... 

A. Ishibashi, Studies of Volumetric Efficiency and Theoretical Delivery of Gear Pumps, Bull. Jp. Soc. Mech. Eng., 13, 688-696 (1970). 

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