Document jNwae90nEjN5KN0qL0mBwjqN

ropes The safeties must be attached to the car frame, and one safety must be located within or below the lower members of the car frame (safety plank) The "Elevator Code" classifies three types of safeties Type A (instantaneous) safeties rapidly in crease their pressure on the guide rails to give a very short stopping distance They are permissible on elevators having a rated speed of not more than 150 fpm Type B safeties apply limited pressure to the guide rails and retarding forces are rea sonably uniform after full application They are permissible on elevators of any speed and may be used in multiple Type C safeties (Type A with oil buffers) are permissible on elevators with a rated speed of not more than 500 fpm Counterweight safeties should conform to the car safety requirements Car switches. The handle of the car switch (operating control) should be designed to return to the "stop" position and lock when the hand of the operator is removed Signal system. Every elevator (except automatic-operation and continuous-pressureoperation elevators) should have a signal system that can be operated from any landing to signal the car when it is wanted at that landing Inspection and maintenance Inspections and tests must conform to re quirements and regulations set forth m the particular municipality Much of the dis cussion in this section is based on AS1 Stand ard A17 2, Practice for the Inspection of Ele vators (Inspectors' Manual), published by the American Society of Mechanical Engineers and also available from the American Stand ards Institute It is important that anyone concerned with maintenance and inspection should have and use a copy of the Code and the Manual A guide for inspection is given in the "Inspectors' Manual," and contains these re quirements 1 Acceptance inspections and tests of all new installations and alterations of eleva tors, dumbwaiters, and escalators should be made by an inspector employed by the enforcing authority 2 Periodic inspections and tests of all in stallations should be made by a person qualified to perform such services, in the presence of an inspector employed or authorized by the enforcing authorities It is recommended that periodic inspec tions and tests be made at intervals not longer than a Three months for power passenger elevators b Six MONTHS for escalators and power freight elevators c Twelve months for hand elevators and power and hand dumbwaiters 3 Maintenance inspections and tests should be made by a person qualified to perform such service in the presence of an inspector employed or authorized by the enforcing authority Car and counterweight safeties, governors, and oil buffers should be given maintenance inspections and tests at least every five years Inspection program. Careful maintenance is essential to the conservation and safe op eration of elevators and their appurtenances, and reduces the need for repairs Frequent and thorough inspections by qualified per sonnel are the first requisite of an efficient maintenance program However, minor dayto-day inspection and maintenance can be performed by plant personnel Items of regular maintenance that require special consideration include lubrication of hoisting and counterweight wire ropes and of oil buffers, cleaning and lubrication of guide rails, controller contactors and relays, and car safety mechanisms, cleaning of hoist ways and pits, machine rooms, and tops ofcars Hoistways and landings. Accidents occur ring or originating at landings usually are due to (a) tapping or slipping at the car entrance or landing, (b) being caught by the car, (c) falling down the hoistway, (d) being caught by the doors To help prevent tripping and slipping ac cidents at hoistway landings, the following points should receive attention 591