AS 5227.1:2021 pdf free.Cranes – Requirements for mechanisms Part 1: General (ISO 10972-1:1998, MOD).
4.3 Couplings
4.3.1 General
Selection of the type of coupling shall be made on the basis of the general design of the mechanism, its use and performance required in order to avoid vibrations and unwanted reactions. Alignment shall comply with the supplier’s instructions.
When necessary, rotating parts shall be statically or dynamically balanced.
4.3.2 Clutches
When sprag-type clutches are used in hoist and derricking systems, they shall incorporate a positive mechanical lock against failure or be designed to transmit twice the maximum torque imposed by the maximum line pull.
Dry friction clutches shall be protected against rain and other liquids such as oil and lubricants. Clutches shall be arranged to permit adjustments where necessary to compensate for wear.
The maximum permissible torque of the clutch shall be at least as high at any operating temperature as the torque impulses occurring during operations, taking into account the impulse frequency and the permissible wear.
4.4 Brakes
Means shall be provided for arresting each powered motion of the crane.
Emergency braking shall be performed using brakes which are automatically applied in case of power failure. The emergency brakes shall provide a deceleration rate consistent with the design parameters for a fully loaded mechanism.
The force to apply a manual in-service brake by hand or foot shall comply with the requirements of ISO 7752.
The same brake may be used for different types of braking, as appropriate.
4.4.1 Hoist brake
The frictional hoist brakes shall be capable of automatically arresting and sustaining any rated load and dynamic test load at any position within the range of hoisting.
When emergency load-lowering is required, the hoist brake shall be capable of manual release so that control of the load will be maintained during lowering. The emergency load-lowering shall be carried out according to readily available instructions which take into account the heat-dissipating capability of the brake.
The hoist brake shall be selected to have a nominal torque that is at least 1,5 times the load torque. Cranes intended for transportation of molten metals or similar hazardous materials shall be equipped
so that dropping of the load is prevented if a component in the force flow fails. This requirement is met by
— having redundant systems, or
— an emergency stopping brake on the rope drum in conjunction with a redundant rope drive, or
— up to a gross load capacity of 16 t, designing the hoist at least two classification groups higher than required for actual operating conditions, and taking MS as the minimum group.AS 5227.1 pdf download.