Section 4.2 Screw-Column Elevators
Electrical wiring, pipes, and ducts in hoistways, machine rooms, and machinery spaces shall conform to Section 2.8, except the main feeder of a screw-column elevator shall be permitted to be installed in the hoistway if the screw machine is located in the hoistway, provided there is no intermediate access to the conductors between the disconnecting means and the termination at the motor or controller.
(a) AISC Book No. S326 or CAN/CSA-S16.1, whichever is applicable (see Part 9) for structural steel
(b) ANSI/ACI 318 or CAN3-A23.3, whichever is applicable (see Part 9) for reinforced concrete
NOTE: In determining unit stresses, the maximum normal loading is doubled to take care of impact, accelerating stresses, etc.
(a) limit the down speed of the car with rated load to notover0.87 m/s (175 ft/min) in the event of failure of the driving means
(b) limit the fall of the elevator in the event of failure of the driving nut to a distance not exceeding 13 mm (0.5 in.), by using a safety nut or other equivalent means
- date of installation of driving and safety nuts
- spacing between driving and safety nuts
The fastening of guide rails to brackets or to the elevator-supporting frame shall be by clips, welds, or bolts. The rail structure and the structural members to which it is attached shall withstand the forces specified in 188.8.131.52, and the application of the car safety shall be within the deflection limits specified.
|A||=||net cross-sectional area of the screw at the root of the thread, mm2 (in.2)|
|L||=||maximum free length of the screw, mm (in.) R = radius of gyration of the screw at the root of the thread, mm (in.)|
|W||=||the total weight with rated load plus one-half the weight of the screw column, kg (lb)|
|W/A||=||maximum allowable fiber stress|
Elevators having a rated speed of 0.5 m/s (100 ft/min) or less shall be designed so that the elevator car will be brought to a stop without damage to the elevator system in the event of overtravel of the elevator at either terminal due to a malfunction.