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General Terms and Definitions |
| Auxiliary Hoist |
A supplemental hoisting unit, usually of lower load rating and higher speed than the main hoist. |
| Axis of Rotation |
The vertical axis around which the crane's superstructure rotates. |
| Boom |
In cranes and derricks usage, an inclined spar, strut, or other long member supporting the hoisting tackle. Also defined as a structural member attached to the revolving superstructure used for guiding and acting as a support for the load. |
| Boom Angle Indicator |
An accessory device that measures the angle of the boom base section centerline to horizontal. |
| Boom Stops |
A devise used to limit the angle of the boom at its highest position. |
| Brake |
A device used for retarding or stopping motion by friction or power means. |
| Block |
Sheaves or grooved pulleys in a frame provided with hook, eye, and strap. |
| Crane |
A machine consisting of a rotating superstructure for lifting and lowering a load and moving it horizontally on either rubber tires or crawler treads. |
| Counterweight |
Weights used for balancing loads and the weight of the crane in providing stability for lifting. |
| Deck |
The revolving superstructure or turntable bed. |
| Drum |
The spool or cylindrical member around which cables are wound for raising and lowering loads. |
| Gantry |
A structural frame work (also known as an A Frame) mounted on the revolving superstructure of the crane to which the boom supporting cables are reeved. |
| Headache Ball |
A heavy weight attached above the hook on a single line or whip line to provide sufficient weight to lower the hook when unloaded. |
| Holding Brake |
A brake that automatically sets to prevent motion when power is off. |
| Jib |
An extension attached to the. boom point to provide added boom length for lifting specified loads. |
| Load |
The weight of the object being lifted or lowered, including load block, ropes, slings, shackles, and any other ancillary attachment. |
| Load Block |
The assembly of the hook or shackles, swivel, sheaves, pins, and frame suspended from the boom point. |
| Main Hoist |
Hoist system or boom used. for raising and lowering loads up to maximum rated capacity. |
| Mechanical Load Brake |
An automatic type of friction brake used for controlling loads in the lowering direction. This device requires torque from the motor to lower a load but does not impose additional loads on the motor when lifting a load. |
| Outriggers |
Support members attached to the crane's carrier frame which are used to the crane and may be blocked up to increase stability. |
| Pawl |
Also known as "dog". It is a gear locking device for positively holding the gears against movement. |
| Pendants |
Stationary cables used to support the boom. |
| Radius |
The horizontal distance from the axis of rotation of the crane's superstructure to the center of the suspended load. |
| Reeving |
The path that a rope takes in adapting itself to all sheaves and drums of a piece of equipment. |
| Running Sheave |
Sheaves that rotate as the hook is raised or lowered |
| Superstructure |
The rotating frame, gantry and boom or other operating equipment. |
| Test Load |
Any load or force, expressed in pounds, used for testing or certifying the limitations within acceptable tolerances of the anticipated load. |
| Two-Block |
The condition in which the lower load lock or hook assembly comes in contact with the upper load block or boom point sheave assembly. |
| Quadrant of Operation |
The area of operation that the lift is being made in. Usually divided into four quadrants, i.e. front, rear and side(s) - left side and right side. |
