They have straight teeth, and are mounted on parallel shafts.
All of the water falls down a parallel shaft only a few metres away.
All of the water from the parallel shaft sinks into the floor at its bottom, and is not seen again in the cave.
They are used to transmit power between two parallel shafts as shown in the adjacent figure.
Initially the boxes were lowered with the aid of a large water bucket descending or ascending a parallel shaft to act as a counterbalance.
Despite the heroic efforts of volunteers who attempted to dig a parallel shaft to free Collins, he was found dead, buried to his shoulders in debris.
The screws are mounted on parallel shafts that have gears that mesh so the shafts turn together and everything stays in place.
Roll sets are typically mounted one over the other on a pair of horizontal parallel shafts supported by a stand(s).
It consisted, not of a single very long barrel, but of a series of parallel shafts.
They looked across a couple of meters of empty space at the cluster of parallel shafts.