Mich. Admin. Code R. 408.7095 - Driving machines and sheaves
Rule 95.
(1) A
sprocket, winding drum, traction sheave and overhead and deflecting sheave
shall be of cast iron or steel. The diameter of a sheave shall not be less than
30 times the diameter of the wire hoisting rope. The rope grooves shall be
machined, except where 8 x 19 steel ropes are used.
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, that is, the rated load plus the weight of the car or chains,
ropes and counterweights, to be used in the design of a driving machine and
sheave, shall be not less than either of the following:
(a) Eight for wrought iron and
steel.
(b) Ten for cast iron, cast
steel, and other material.
(3) A set screw fastening shall not be used
instead of a key or pin if the connection is subject to torque or
tension.
(4) A friction-gearing or
clutch mechanism 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) A driving machine
shall be equipped with an electrically released spring-applied brake.
(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.
Notes
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