ASME HST-6-2020 pdf download
ASME HST-6-2020 pdf download.Performance Standard for Air Wire Rope Hoists.
Service conditions have an importantinfluence on the performance ofwearingparts ofa hoist, such as gears, bearings, rope, sheaves, brake linings, load and lift limitdevices, wheels, and pneumatic components. Careful consideration ofthe hoist duty service classifications described in this Section will enable the user to evaluate the application and obtain a hoistdesigned for optimum performance and minimum maintenance. Ifdoubtexists regarding hoistselection, the hoist supplier should be consulted. Many factors enter into the selection of the proper hoist to perform a given function. Hoisting equipment consists of both mechanical and pneumatic components, and both must be considered when analyzing the service the hoist must perform. The factors that influence the performance of any hoist include the following: (a) LoadDistribution. Loaddistributionistheactualdistributionorproportionoffullandpartialloadstobehandledby the equipment, including lifting devices, and has an important effect on the life ofpower transmission components. For example, ball bearinglife varies accordingto the cube ofthe load. A2-ton (1 814.4-kg) hoistoperated ata mean effective load of 1 ton (907.2 kg) will have a ball bearing life of 8 times that of the same hoist used steadily at its rated load. (b) Operational Time. Operational time is the total running time of the hoist per hour or per work period. (c) Repetitive Long Lowering Operations. Such operations generate heat in control braking means. (d) Environmental Conditions. Examples include high or low ambient temperatures, dust, moisture, and corrosive fumes. 6-1.2.2 Hazardous Locations When hoists are used in hazardous locations as defined byNFPA70 orotherspecial codes, modifications or additional precautionsnotcoveredbythisStandardmayberequired.Intheselocations,onlyhoistsdesignedinamannersuitablefor the conditions encountered shall be used. Nonmandatory Appendix B provides guidance for both the manufacturer and end user to assist in configuring a hoist to make it suit6-1.5.2 Hand-Chain-Operated Trolleys For hand-chain-operated trolleys, motion is obtained by pulling on the hand chain that is connected to trolley wheels throughgearsorsprockets.Thistypeisrecommendedwheretrolleymotionisrelativelyinfrequentorshort,andforthose capacities and beam heights where a plain-type trolley would be impractical. The hand-chain-operated trolley provides good load-spotting ability. Thehandchainshallbeguardedto preventhandchaindisengagementfromthehandchainwheel. Thehandchainshall withstand, without permanent deformation, a force of3 times the pull required to traverse the trolley with rated load. 6-1.5.3 Motor-Operated Trolleys Amotor-operatedtrolleyisrecommendedwhereoperatingfrequency,distanceoftravel,ratedload,beamelevation,or the type of load being handled exceeds recommendations for the use of plain or hand-chain-operated trolleys. The design ofmotor-operated trolleys shall be based on intermittent operation on a straight beam, unless otherwise specified.
Where trolley travel involves a curved beam, beam switches, exceptionally long runs, or near continuous operation, special design may be required. Full particulars should be provided with the inquiry. Brakes, when specified, may be actuated by mechanical or pneumatic means, and shall have the following characteristics: (a) sufficient capacity to stop the trolley within a distance in feet (meters) equal to 10% of the rated speed in feet (meters) per minute when traveling at rated speed with rated load (b) heat dissipation capability for the specified frequency of operation (c) provisions for adjustment where necessary to compensate for wear 6-1.5.4 Trolley Wheels When a trolley is required for use with a hoist, the type and size ofthe support beam shall be specified to ensure the trolley wheel contour is suitable for the contour of the beam. 6-1.5.5 Air Supply Characteristics Air supplycharacteristics should be as specified bythe manufacturer. Refer to the technical manual provided with the hoist, or contact the hoisSECTION 6-2.3: CONTROL Hoists and trolleys shall have pendant, pull cord, or rod control. Control actuators shall spring return to the “OFF” position. 6-2.3.1 Pendant Control (a) The pendant control station shall be supported to protect the pneumatic hoses against strain. (b) The pendant control station shall be clearly marked to indicate the function of each actuator. (c) Unless otherwise specified, the standard pendantcontrol shall have a length that will locate the pendantapproxi- mately 3 ft to 5 ft (0.9 m to 1.5 m) above the lower limit of lift. 6-2.3.2 Pull Control Pull control shall consist of two pull chains or cords with suitable handle(s) clearly marked for direction. Unless otherwise specified, the standard pull control shall have a length that will locate the control handles approximately 3 ft to 5 ft (0.9 m to 1.5 m) above the lower limit of the lift. 6-2.3.3 Rod Control Rod control shall permit control of hoist or trolley motion by linear or rotary movement of the rod handle, or a combination of both. The rod handle shall be clearly marked for direction of motion. Unless otherwise specified, the rod handle shall be located 3 ft to 5 ft (0.9 m to 1.5 m) above the lower limit of lift.
