The shaft 3 is carried in a suitable bearing 5 and has secured to it, near its lower end, a clutch plate 6. The clutch plate 6 is adapted to engage a second clutch plate 7 immediately beneath it, limestone crushing equipment and this second clutch plate is secured to the top of a driven tubular shaft 8 which is coaxial with the shaft 3, the shafts 3 and 8 being aligned one with the other by the end of the one projecting into the end of the other.
The shaft 8 is shown as made in two sections but these sections are rigidly connected together and the shaft is aligned by bearings 10 and If secured to the main frame I. Downward thrust on the shaft 8 is transmitted through a thrust bearing 12 to the main frame I.Adjacent the bearings 10 and II, rigidly secured to the shaft 8, ore processing equipment are bevel gears 14 and 15 which engage bevel gears 16 and 17 respectively upon hollow shafts 18 and 19 carried in bearings 20 and 21 secured to the main frame I. The hollows in the shafts 18 and 19 are of square section and are adapted to engage square shafts 22. The shafts 18 and 19 are confined axially by the bevel gears 16 and 17 and by collars 24 and 25.
The weight of the bowl 2 and of its contents is transmitted through the shaft 3 to the upper clutch plate 6 and by it to the lower clutch plate 7 whence it is transmitted through the shaft 8 and through the thrust bearing 12 to the main frame I. Drive applied to the shaft 8 by the square shaft 22 is thus normally transmitted through the clutch plates to the bowl 2, but to stop the rotation of the bowl 2, when such is desired, two rockshafts 30 and 31 are provided which are supported in bearings in the main frame I and these rockshafts have upon them arms 32 and 33 which have upon their ends rollers adapted to engage the underside of the upper clutch plate 6. When those rockshafts 30 and 31 are operated the clutch plate 6 is lifted from engagement with the clutch plate 7, the shaft 3 sliding upward in its bearing 5 and the bowl coming to rest. Reverse movement of the rockshafts 30 and 31 causes the clutch plates to re-engage. One or both of the clutch plates 6 and 7 may have their engaging surfaces leather or fabric faced to ensure a positive transmission of the drive.