Lift machine

• Pages: 52-54

A8 Lift machine

A8.1. Methods of driving the car and the counterweight

A8. 1.1.The two following driving methods may be used:

by traction (use of sheaves and ropes);

by fixed attachment (use of a winding drum and ropes, or

chain drive wheels and chains).

A8.2. Use of belts to drive the machine

A8.2. 1.Belts may be used to couple the motor or motors to

the rotating part subjected to the mechanical brake action, pro-

vided that the belts are of the 'CV,' or toothed type; that there is at

least one more than the minimum number determined by calcula-

tion; and that in any case there are never less than three.

A8.3. Use of overhung sheaves or pulleys

A8.3.l. When overhung sheaves or pulleys are used, arrange-

ments should be made to prevent the ropes from leaving the sheave

or pulley grooves.

A8.4. Brake system

A8.4. 1.Thd lift should be fitted with a brake system which

must include a mechanical brake; additional means of deceleration

may be provided, for example dynamic braking.

A8.4.2. The brake system should act automatically in case of

failure of the electric supply to the machine or the controls.

A8.4.3. The brake system should be capable of stopping a

descending car travelling at contract speed with its contract load

increased by 25 per cent.

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