AS 5227.1 pdf download

AS 5227.1 pdf download.Cranes — Requirements for mechanisms
1  Scope
This part of ISO 10972 establishes requirements which apply generally to mechanisms and related components of cranes and lifting appliances as described in ISO 4306‑1, ISO 4306‑2 and ISO 4306‑3. Requirements concern: a) general layout and design of mechanisms; b) selection and/or design requirements of components; c) instructions for manufacture, mounting, installation and testing. Rules for proof of competence calculation regarding different limit states (yield strength, fatigue, wear) are excluded from this part of ISO 10972.
3  Definitions
For the purposes of this part of ISO 10972, the definitions given in ISO 4306‑1, ISO 4306‑2 and ISO 4306‑3 and the following definitions apply. 3.1 in‑service braking Stopping or slowing the crane motion with the motor disconnected, through an immediate and easy control by the operator from the normal working position. 3.2 out‑of‑service braking Avoiding unwanted starts for indefinite periods of time. Note 1 to entry: Actuation may be automatic or manual. 3.3 emergency braking Stopping the crane motion or motions in the case of loss of power or pressure supply through engagement with a limiting device or the activation of an emergency stop switch. 3.4 control braking Maintaining a desired speed, automatically or by the operator, with the motor engaged. 3.5 chain drive Device for supporting and moving loads via chain and roller arrangement.
4  General
4.1  Design criteria 4.1.1  General design and layout General design and layout of a crane mechanism shall take into consideration: — requirements of the user; — specific function of the mechanism and its use; — reliability of the mechanism, considering the consequences of failure; — displacement of the structure supporting the mechanism; — avoidance of uncontrolled motions considering the limits of transmission of force or moments, when provided for example by motors, clutches, brakes; — avoidance of undesirable or excessive vibrations; — avoidance of excessive noise emissions; — ease of use and controls of the mechanism with adequate space and motion limiters and indicators; — recommendations of the component supplier for the selection and installations of component parts; — serviceability, i.e. easy accessibility for maintenance of components (see ISO 11660‑1); — interchangeability of components; — availability of lifting lugs or lifting points for handling; — access for operator or maintenance personnel, see ISO 11660‑1; — environmental conditions and hazards. 4.1.2  Criteria for strength of components When selecting the components of the mechanisms, it shall be verified that the applicable loading conditions in terms of maximum loading, load spectrum and number of load cycles comply with the corresponding rated characteristics of the components. 4.2  Power The power mechanism shall be an electrical, hydraulic or pneumatic motor or an internal combustion engine. The crane mechanism shall have sufficient power and torque to control the motions under the specified design conditions. Gravitational, inertial, in‑service wind, friction forces and mechanism efficiency shall be taken into account.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.