Rules & Regulations of the State of Tennessee
Title 0800 - Labor and Workforce Development
Subtitle 0800-03 - Boilers, Elevators, Amusement Devices, and other Related Rules
Chapter 0800-03-07 - Sewer Lift Station, Personnel Elevators
Section 0800-03-07-.17 - DRIVING MACHINE AND SHEAVES

(1) Sprockets, winding drums, traction sheaves and overhead and deflecting sheaves shall be of cast iron or steel the diameter of the wire hoisting ropes. The rope grooves shall be machined.

EXCEPTION: Where 8 x 19 steel ropes are used, the diameter of drums and sheaves may be reduced to 21 times the diameter of the rope.

(2) The factor of safety, based on the static load (the rated load plus the weight of the car or chains, ropes, counterweights, etc.) to be used in the design of driving machines and sheaves shall not be less than:

Eight (8) for wrought iron and steel

Ten (10) for cast iron, cast steel and other material

(3) Set-screw fastenings shall not be used in lieu of keys or pins if the connection is subject to torque or tension.

(4) Friction-gearing or clutch mechanisms shall not be used for connecting the sprockets, drum or sheaves to the main driving gear.

(5) Worm gearing having cast-iron teeth shall not be used.

(6) Driving machines shall be equipped with electrically released spring-applied brakes.

(7) A single ground or short circuit, a counter-voltage or a motor field discharge shall not prevent the brake magnet from allowing the brake to set when the operating device is placed in the stop position.