Most shafts are supported at 2 bearings. These bearings have to provide axial and radial support in a manner that does not over-constrain the shaft. That is, together they allow only one degree of freedom for the shaft, ie its rotation. Over-constraint may take place where 2 bearings may be set up to provide the same function. If proper tolerances are not provided such bearings may in fact provide a load for each other.

Large conveyor drive pulleys

A hot hammer forged shaft blank, apparently intended to have integral gears or couplings at its end. The compressive residual stresses are useful in reducing tensile fatigue failures originating from its surface.

Thruster brake Grain elevator Inching gear drive for maintenance Drive motor

Gear coupling. Necessary to allow alignment between the output shafts from gear box to input to grain elevator

A Cooper bearing, that splits horizontally through inner and outer tracks for ease of removal

An older but still operational elevator drive, with worm gear box, and bronze plain slide bearing

The use of shaft mounted gearbox as shown here, have become very popular. This is largely because if the box and the shaft are not mounted separately their alignment is difficult to guarantee. The weight due to the box typically causes an insignificant increase in shaft stresses.

Since these are solid couplings, this is essentially a shaft mounted gear box

Locomotive drive motor and axle set. Note motor is fixed to chassis while wheel’s axle moves with the track. Ring gear coupling Pin and rubber coupling

An example of a shaft (or may be called hinge pin, even an axle) where shear stresses may be as significant as bending stresses.

Means of reducing stress concentration where a shaft enters a boss or housing

In nearly all shafts deflection is closely constrained, yet there are instances where the shaft is designed to be rigid in torsion but not in bending.

Estimating a point location for a load in bearings which are designed to take a distributed load.

Port Waratah & Korangang Island coal loadersA. lozzi 09

Australia is not short of coal deposits. Many years ago this island had high mountains and extensive forests. It looks like extreme storms washed and pushed large amount of vegetation down to what may have been the coast. There it was covered with sediment that excluded oxygen, forming over many years coal, gas and maybe oil.