Cmaa specification no.70

Each brake shall have a minimum torque rating equal to rated load hoisting torque at the point where the brake is applied. While much of this information must be of a general nature, the items listed may be checked with individual manufacturers and comparisons made leading to optimum selection of equipment. A crane which when activated operates through a perset cycle or cycles. Operation at elevated voltages may result in unsatisfactory operation, such as, excessive torques. All other load carrying parts shall be designed so that the calculated static stress in the material, based on rated crane capacity, shall not exceed 20 percent of the published average ultimate strFlnal:

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Where interpretations differ, C. ThiS brake shall be applied directly to the motor shaft or some other shaft in the hoist gear train. Where cmaq, an auxiliary girder or other suitable means should be provided to support over-hanging loads to prevent undue torsional and lateral deflections.

Bridge conductors, runway collectors and other accessory equipment may be removed for shipment.

Crane Specifications and Technical Papers

If storage is required, arrangements should be made with the manufacturer for extra protection. They shall each have a moment of inertia no less than: A structurai member other than the end truck which connects the ends of the girders to maintain the squareness of the bridge. The wind load on the trolley shall be considered as s;ecification divided between the two girders.

With the introduction of Specification 78, CMAA intends to set higher performance standards and raise customer expectations related to the service of overhead traveling cranes and associated hoisting equipment. A crane similar to an overhead crane except that the bridge for carrying the trolley or trolleys is rigidly supported on two or more legs running on fixed rails or other runway.

When flangeless wheel and side roller assemblies are provided, they shall be of a type and design recommended by the crane manufacturer.

Horizontal forces pel'pendi,cu axis of the member specificatiion considered. The L life of an antifriction bearing is the minimum expected iife, hours, of 90 percent of a group of bearings which are operating at a given speed and loading.

To be specified by the manufacturer as open, having only sides or specificatoon railing around the operator, or enclosed, complete with roof, dows, etc.

Seismic forces are not considered in this design specificatid However, if required, accelerations shall be specified at the crane rail elevation by the owh or specifier. Trolley drive motor horsepower shall use same selection procedure cranes per section 5.

This percentage shall be applied to both the live and dead loads, exclusive of the endtrucks and end ties.

The principal horizontal beams of the crane bridge which supports the trolley and is supported by the end trucks. The motor is connected to a self-contained gear reduction unit located near the center of the bridge. Shafting in bearing must be checked for operating conditions.

CMAA Specification 70

A speed point may be manual hand controlled, or automatic. Contacting devices for collecting current from the runway or bridge conductors. The runway rails should be standard rail sections or any other commercial rolled sections with equivalent specifications of a proper size for the crane to be installed and must be prOVided with sppecification rail splices and holddown fasteners.

Complete the building drawing below making special note of any obstructions which may interfere with the crane including special clearance requirements under girders or cab. These factors are obtained from the following formulas: If the ratio of A device, other than a motor, used for retarding cnaa stopping motion by friction or power means. A girder arranged parallel to the main girder for supporting the platform, motor base, operator's cab, controi panels, etc.

Tensile and bending stress, ie, a B. These additional loadings may be included in a simplified manner by the application of a separate factor for the dead load DLF and for the hoist load HLF by which the vertical acting loads, the member forces or the stresses due to them, must be multiplied. These specifications do not cover equipment used to lift, lower, or transport personnel suspended from the hoist rope system. The footwalk shall be protected on all exposed suitable toe guard.

Specification Computing and Systems Development Specification. Also, two sets of operating instructions and spare parts information are typically furnished. For the purpose of this specification, the strength and durability shall be based on the torque required to lift the rated load for hoist gearing and the motor name plate rating for travel gearing.

An individual set of acceleration resistors for each motor shall be provided unless otherwise specified.

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