Date: 07/11/2019
Previous Blog - ControlMaster® Anti-Sway System
GLOSSARY SECTIONS
CRANE BASICS | CRANE MECHANICS
CRANE ELECTRICS | CRANE LAYOUT | CHAIN
CRANE BASICS
ADJUSTABLE FREQUENCY DRIVE: A motor controller designed to convert fixed frequency AC power to available frequency power for AC motor speed control. The system is used in conjunction with a squirrel cage motor to control speed over a relatively wide, constant torque range, by maintaining a constant voltage / frequency ratio. This type of control “leashes” the in-rush current to deliver startup power to the motor as efficiently as possible providing a soft-start feature thereby minimizing load swing.
AUXILIARY HOIST: Supplemental hoisting unit usually of lower load rating and higher speed than the main hoist.
BELOW -THE-HOOK LIFTING DEVICES: Devices that are not normally reeved onto the hoist rope or chain, such as hook-on buckets, magnets, grabs, and other supplemental devices used for ease of handling certain types of loads. The weight of these devices is to be considered part of the load to be lifted.
BLOCK, LOAD: The assembly of hook, swivel, bearings, sheaves, pins and frame suspended from the hoisting ropes. In a “short type” block, the hook and the sheaves are mounted on the same member, called the swivel. In a “long type” block, the hook and the sheaves are mounted on separate members. (The supporting member for the sheaves is called the sheave pin and the supporting member for the hook is called the trunnion.)
BLOCK, UPPER: A fixed assembly of sheaves, bearings, pins and frame, located on the trolley cross members, and which supports the load block and its load by means of the ropes.
BOGIE: A short end truck attached to the end of one girder (or to a connecting member if more than one bogie is used per girder). This type of end truck is used when more than four wheels are required on a crane due to the design of the runway.
BOGIE, EQUALIZING: A short end truck which is flexibly connected to one girder (or connecting member) by means of a pin upon which the truck can oscillate to equalize the loading on the two truck wheels. This construction uses a very rigid end tie between the girders.
BOGIE, FIXED: A short end truck which is rigidly connected to one girder. A flexible end tie is used between the girders to permit equalization of the wheel loads by torsional deflection of the girders and flexing of the end tie.
BRAKE: A device, other than a motor, used for retarding or stopping motion by friction or power means.
BOX SECTION: The rectangular cross section of girders, trucks or other members comprised of two (2) rolled steel side plates, a top plate, and a bottom plate.
BRIDGE: The part of a crane consisting of one or more girders, trucks, end ties, foot walks, and drive mechanism, which carries the trolley or trolleys.
BRIDGE GIRDERS(s): The primary horizontal beam of the crane bridge which supports the trolley and is supported by the end trucks.
BRIDGE TRAVEL: The crane movement in a direction parallel to the crane runway.
CAB OPERATED CRANE: A crane which is controlled by an operator from a cab that is attached to the crane.
CAMBER: The slight, upward, vertical curve given to girders to partially compensate for deflection due to rated load and weight of the crane parts.
CAPACITY: The maximum weight in tons the crane will be required to lift.
CLEARANCE: The minimum distance from any part of the crane to the point of nearest obstruction.
COLLECTORS, CURRENT: Contacting devices for collecting current from runway or bridge conductors.
CONDUCTORS, BRIDGE: The electrical conductors located along the bridge structure of a crane that transmit control signals and power to the trolley(s).
CONDUCTORS, RUNWAY (MAIN): The electrical conductors located along a crane runway that transmit control signals and power to the crane.
CONTROLLER: A device or group of devices that serves to govern, in a predetermined manner, the power delivered directly to the apparatus to which it is connected.
CONTROL PANEL: An assembly of components (magnetic, static, hydraulic, pneumatic, etc.) that governs the flow of power to or from a motor or other equipment in response to signals from a master switch, push-button station, remote control, automatic program, or other similar device.
CONTROL PENDANT: A device that gives an operator precise control over the motions of the crane.
CRANE: A machine for lifting and lowering a load and moving it horizontally, with the hoisting: mechanism being an integral part of the machine.
CRANE, AUTOMATIC: A crane which, when activated, operates through a preset cycle or cycles.
CRANE, CAB OPERATED: A crane whose movements are controlled by an operator using controllers located in a cab that is attached to the crane.
CRANE, CANTILEVER GANTRY: A gantry or semi gantry crane in which the bridge girders or trusses extend transversely beyond the crane runway on one or both sides.
CRANE, FLOOR-OPERATED: A crane whose movements are controlled by an operator using controllers contained in a pendant station suspended from the crane.
CRANE, GANTRY: 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 another runway.
CRANE GIRDER(s): See Bridge Girder(s).
CRANE, HOT MOLTEN-MATERIAL-HANDLING (LADLE): An overhead crane used for transporting or pouring molten material.
CRANE, MANUALLY OPERATED: A crane whose hoist mechanism is driven by pulling an endless chain, or whose travel mechanism is driven in the same manner or by manually moving the load or hook.
CRANE, OUTDOOR: An overhead or gantry crane that operates outdoors and for which provisions are not available for storage in an area that provides protection to the crane from weather conditions. An indoor crane that may operate outdoors on a periodic basis is not classified as an outdoor crane.
CRANE, OUTDOOR STORAGE GANTRY: A special type of gantry crane of long span and with long legs, usually used for the storage of bulk material such as ore, coal, limestone, or sand. This type of crane normally will have one or two cantilevered girder ends with through legs.
CRANE, OVERHEAD: A crane with a single or multiple girder movable bridge carrying a movable or fixed hoisting mechanism and traveling on an overhead fixed runway structure.
CRANE, POLAR: An overhead or gantry crane that travels on a circular runway.
CRANE, POWER-OPERATED: A crane whose mechanism is driven by electric, pneumatic, hydraulic, or internal combustion means.
CRANE, PULPIT-OPERATED: A crane whose movements are controlled by an operator using controllers located in a control room or a fixed or movable cab or platform that is independent of the crane.
CRANE, REMOTE-OPERATED: A crane whose movements are controlled by an operator using controllers contained in a portable operating station not attached to the crane.
CRANE, SEMIGANTRY: A gantry with one end of the bridge rigidly supported on one or more legs that run on a fixed rail or runway, the other end of the bridge being supported by an end truck running on an elevated rail or runway.
CRANE SPAN: The horizontal distance center to center of the both runway beams.
CRANE, STANDBY: A crane not in regular service that is used occasionally or intermittently as required.
CRANE, WALL: A crane having a cantilever frame with or without trolley and supported from a side wall or line of columns of a building. It is a traveling type and operates on a runway attached to the side wall or columns.
CREEP SPEED: A very slow, constant, continuous, fixed rate of motion of the hoist, trolley, or bridge: usually established at 1% to 10% of the normal full load speed.
DEFLECTION, DEAD LOAD: The vertical displacement of a bridge girder due to its own weight plus the weight of parts permanently attached thereto, such as footwalk, drive mechanism, motor and control panels. The dead load deflection is fully compensated for in the girder camber.
DEFLECTION, LIVE LOAD: The vertical displacement of a bridge girder due to the weight of the trolley plus the rated load.
DOUBLE GIRDER: An overhead crane consisting of two end trucks, two bridge girders and the trolley hoist unit. The trolley runs on rails on top of the bridge girders.
DRIVE: The assembly of the motor and gear unit used to propel the bridge or trolley.
ELECTRIFICATION SYSTEM: The various parts of the crane structure that supply and apply electricity to the trolley hoist.
EMERGENCY STOP (E-STOP): A manually or automatically operated electric switch to cut off electric power independently of the regular operating controls.
END TRUCK: An assembly consisting of structural members, wheels, bearings, axles, etc., which supports the bridge girder(s) or the trolley cross member(s)
EXPLOSION-PROOF CRANE: An explosion-proof crane is created with specially constructed electrical components. These components prevent the ignition of hazardous materials in the surrounding atmosphere by containing any explosions that may occur within the components.
FAIL-SAFE: A provision designed to automatically stop or safely control any motion in which a malfunction occurs.
FESTOON: A method for providing power to a hoist traveling along a beam.
FLOOR-OPERATED CRANE: A crane which is controlled by an operator using a pendant station which is suspended from the crane.
FOOTWALK: A walkway with handrail and toe boards, attached to the bridge or trolley for access purposes.
GANTRY CRANES: An overhead crane where the bridge girder(s) are connected to “legs” on either side of the span. These “legs” eliminate the supporting runway and column system and connect to end trucks which run on a rail either embedded in, or laid on top of, the floor.
GAUGE: The horizontal distance center to center of the bridge rails.
GIRDER, BRIDGE: The principal horizontal beam(s) of the crane, which supports the trolley, is supported by the end trucks, and is perpendicular to the runway.
GIRDER, RUNWAY: A horizontal beam attached to the building columns
HOIST: A machinery unit that is used for lifting or lowering a load.
HOIST, AUXILIARY: A supplemental hoisting unit, usually designed to handle lighter loads at a higher speed than the main hoist.
HOIST DRUM: A rotation cylindrical spool with side flanges used to wrap the winch rope during the raising and lowering of the load with the winch.
HOIST MOTION: Motion that lifts or lowers a load.
HOIST, MAIN: The primary hoist mechanism provided for lifting and lowering the rated load of the crane.
HOOK APPROACH, END: The minimum horizontal distance, parallel to the runway, between the centerline of the hook and the face of the wall (or columns) at the end of the building.
HOOK HEIGHT: See Lift Height.
LIFT (HOOK TRAVEL): The maximum vertical distance through which the hook can move, as determined by the length of rope and/or the number of grooves on the drum. The lift height is the maximum vertical distance from the floor that the hook
LIFTING DEVICES: Devices that are not reeved onto the hoist ropes, such as hook-on buckets, magnets, grabs, and other supplemental devices used for ease of handling certain types of loads. The weight of these devices is to be considered part of the rated load.
LIMIT DEVICE: A device that is operated by some part or motion of a power-driven hoist, trolley, or bridge to limit motion.
LIMIT SWITCH: An electrical device which is operated by the bridge, trolley, or hoist motion to disconnect the circuit, to establish a new circuit, or to provide a warning.
LOAD: The total superimposed weight on the load block or hook.
LOAD CYCLE: One (1) lift cycle with load plus on lift cycle without load.
LOAD, DEAD: The load(s) on a portion of the crane, which remain(s) in a fixed position relative to the member being considered.
LOAD, LIVE: A load which moves or varies relative to the member being considered. For the trolley, the live load consists of the rated load plus the weight of the block. For the bridge, the live load consists of the rated load plus the weight of the trolley.
LOAD, RATED: The maximum static vertical load for which a crane or an individual hoist is designed.
MAIN HOIST: The primary hoist mechanism provided for coasting. lifting and lowering the rated load.
NRGMASTER ENERGY CHAIN: It is an alternative to the traditional C-track festoon system. The electrification consists of power and control cables that are enclosed in a flexible chain. The chain rests in a guide channel that is fastened to the web of the bridge girders.
OPEN WINCH CRANE: Ideal for demanding process use as they are for assembly and maintenance. Flexible enough for almost any industrial setting, they combine the latest in advanced design with hardy electronics and a sharp computer intelligence that gives you total control over your materials handling.
OUTDOOR CRANE: An outdoor overhead or gantry crane that cannot be stored indoors or protected from adverse weather conditions. A crane that may operate outdoors on a periodic basis is not classed as an outdoor crane.
OVERHEAD CRANE: A crane with a single or multiple girder movable bridge carrying a movable or fixed hoisting mechanism and trolley and travelling on an overhead fixed runway structure.
OVERLOAD: Any hook load greater than the rated load.
PENDANT STATION: Controls suspended from the crane for operating the unit from the floor.
POWER SUPPLY: The electrical service available in the building for which the crane is being designed.
RADIO REMOTE CONTROL: The radio control performs exactly like the pendant but operates using a radio frequency.
RATED LOAD: The maximum load a crane is designed to handle.
RAIL, BRIDGE: The track supported by the bridge girder(s), on which the trolley travels.
RAIL, RUNWAY: The track supported by the runway beams, on which the crane travels.
RATED LOAD (CAPACITY): The maximum load designated by the manufacturer for which a crane or individual
hoist is designed and built.
REEVING: A system in which a rope travels around drums or sheaves.
REMOTE OPERATED CRANE: A crane which is controlled by an operator using an operating station which is not attached to the crane (for example, radio control).
RUNWAY: An assembly of rails, beams, girders, brackets, and framework on which the crane travels.
RUNWAY CONDUCTORS: The main conductors mounted on or parallel to the runway which provide electrical current to the crane.
RUNWAY RAIL: The rail supported by the runway beams on which the bridge travels.
SEMI-GANTRY CRANE: A gantry crane with one end of the bridge rigidly supported on one or more legs that run on a fixed rail or runway, the other end of the bridge being supported by a truck running on an elevated rail or runway.
SERVICE PLATFORM: A means provided for workers to perform maintenance, inspections, adjustments, and repairs of cranes.
STANDBY CRANE: A crane which is not in regular service but is used occasionally or intermittently as required.
TOP RUNNING CRANE: An overhead or gantry crane that travels on top of the runway structure.
TROLLEY: The unit that travels on the bridge rails and supports the load block.
TROLLEY TRAVEL: The trolley movement.
TROLLEY HOIST: The unit consisting of both the hoist and the trolley frame.
TRUCK: A unit consisting of a frame, wheels, bearings, and axles that supports the bridge girders, the end ties of an overhead crane, or the sill of a gantry crane.
TWO-BLOCKING: Inadvertent physical contact between the load block and the upper block or other part of the trolley.
UNDERRUNNING: An overhead crane that travels under the runway structure, also known as underhung or underslung.
WHEELBASE: The distance from center .to center of the outermost wheels of the bridge or trolley, measured parallel to the rail.
WHEEL LOAD, BRIDGE: The vertical force (without impact) produced on any bridge wheel by the sum of the rated load, trolley weight and bridge weight, with the trolley so positioned on the bridge as to give maximum loading.
WHEEL LOAD, TROLLEY: The vertical force (without impact) produced on any trolley wheel by the sum of the rated load and the trolley weight.
WIRE ROPE HOIST: A very durable hoist that will provide long term, reliable usage.
CRANE MECHANICS
AXLE, FIXED: A shaft which is fixed in the end truck and about which the wheel revolves.
AXLE, ROTATING: A shaft which is fixed in the wheel and which rotates on bearings fixed in the end truck.
BEARING LIFE: The B-10 life of an anti-friction bearing is the minimum expected life in hours of 90% of a group of bearings which are operating at a given speed and loading.
BRAKE: A device, other than a motor, used for retarding or stopping motion by friction or power means.
BRAKE, EDDY CURRENT: A device for controlling load speed in the hoisting or lowering direction by placing ma supplementary load on the motor. This load results from the interaction of magnetic fields produced by an adjustable direct current in the stator coils and induced currents in the rotor.
BRAKE, HOLDING: A friction brake for a hoist that is automatically applied and prevents motion when power to the brake is off.
BRAKE, MECHANICAL LOAD: An automatic type of friction brake used for controlling loads in a lowering direction. This unidirectional device requires torque from the motor to lower a load but does not impose any additional load on the motor when lifting a load.
BRAKE, PARKING: A friction brake for bridge or trolley, automatically applied when power to the crane is interrupted.
BRAKING, CONTROL: A method of controlling speed by removing energy from the moving body or by imparting energy in the opposite direction.
BRAKING, COUNTER TORQUE (PLUGGING): A method of controlling speed by reversing the motor line voltage polarity or phase sequence to develop torque in the direction opposite the rotation of the motor.
BRAKING, DYNAMIC: A method of controlling speed by using the motor as a generator, with the energy being dissipated in resistors.
BRAKING, EDDY CURRENT: A method of controlling or reducing speed by means of an electrical induction load brake.
BRAKING, EMERGENCY: A method of decelerating a drive when power is not available. The braking effort may be established as a result of action by the operator, or automatically when power to the drive is interrupted.
BRAKING, HYDRAULIC: A method of controlling or reducing speed by means of displacement of a liquid.
BRAKING MEANS: A method or device used for stopping/holding motion by friction or power.
BRAKING, MECHANICAL: A method of controlling or reducing speed by friction.
BRAKING, PNEUMATIC: A method of controlling or reducing speed by means of compressed gas.
BRAKING, REGENERATIVE: A method of controlling speed in which the electrical energy generated by the motor is fed back into the power system.
BUMPER (BUFFER): A device for reducing impact when a moving crane or trolley reaches the end of its permitted travel, or when two moving cranes or trolleys come into contact. This device may be attached to the bridge, trolley, or runway stop.
CAMBER: The slight, upward, vertical curve given to girders to partially compensate for deflection due to rated load and weight of the crane parts.
COVER PLATE: The top or bottom plate of a box girder.
DEFLECTION, DEAD LOAD: The vertical displacement of a bridge girder due to its own weight plus the weight of parts permanently attached thereto, such as footwalk, drive mechanism, motor and control panels. The dead load deflection is fully compensated for in the girder camber.
DEFLECTION, LIVE LOAD: The vertical displacement of a bridge girder due to the weight of the trolley plus the rated load.
DIAPHRAGM: A vertical plate (or channel) between the girder webs, which serves to support the top cover plate
and bridge rail and to transfer the forces of the trolley wheel loads to the webs.
DRUM: The cylindrical member around which the ropes are wound for lifting or lowering the load.
END STOP: A device to limit the travel of a trolley or crane bridge. This device normally is attached to a fixed structure and does not normally have energy absorbing capability.
END TIE: A structural member that connects the ends of the bridge girders to maintain squareness of the bridge.
EQUALIZER or EQUALIZER SHEAVE: A device that compensates for unequal length or stretch of a rope.
FLEET ANGLE: The angle formed by the wire rope and the drum groove or sheave groove in the plane which contains the wire rope and is parallel to the drum or sheave axis.
HOIST DRUM: A rotation cylindrical spool with side flanges used to wrap the winch rope during the raising and lowering of the load with the winch.
HOIST MOTION: Motion that lifts or lowers a load.
HOLDING BRAKE: A brake that automatically prevents movement when there is no power.
HOOK APPROACH, SIDE: The minimum horizontal distance, perpendicular to the runway, between the centerline of a hook (main or auxiliary) and the centerline of the runway rail.
LOAD BLOCK: The assembly of hook or shackle, swivel, bearing, sheaves, sprockets, pins, and frame suspended by the hoisting rope or load chain. This shall include any appurtenances reeved in the hoisting rope or load chain.
LOAD SUSPENSION PARTS: The load suspension parts of the hoist are the means of suspension (hook or lug), the structure or housing which supports the drum or load sprocket, the drum or load sprocket, the rope or load chain, the sheaves or sprockets, and the load block or hook.
MECHANICAL LOAD BRAKE: An automatic unidirectional mechanical friction brake which controls the descent speed of loads. The mechanical load brake does not impose additional load on the motor when it is raising a load but motor torque is required to lower loads.
NON-RUNNING SHEAVE: A hoist sheave used to equalize tension in opposite parts of the rope or chain. Because of its slight movement, it is not termed a running sheave.
PARTS OF LINE: The number of lines of rope supporting the load block. Sometimes referred to as parts or parts of reeving.
PINION: The small gear in a gear train which drives the other gears.
PITCH DIAMETER: The distance, measured through the center of a drum or sheave, from center to center of a rope passed about the periphery of the drum or sheave.
RAIL SWEEP: A device attached to the crane and located in front of the crane’s leading wheels to remove obstructions.
REEVING: A system in which a rope travels around drums or sheaves.
ROPE: A wire rope, unless otherwise specified.
ROTATING AXLE: An axle which rotates with a wheel.
RUNNING SHEAVE: A hoist sheave that rotates as the load block is lifted or lowered.
SHEAVE: A grooved wheel or pulley used with a rope to change direction and point of application of a pulling force.
TORQUE, LOCKED-ROTOR: The minimum torque which a squirrel-cage motor will develop at rest, for all angular positions of the rotor, with rated voltage applied at rated frequency. Not applicable to wound-rotor (slipring) motors.
TORQUE, MOTOR BREAKDOWN: The maximum torque which a squirrel-cage or wound-rotor (slip-ring) motor will develop with rated voltage applied at rated frequency, without an abrupt drop in speed.
TORQUE, MOTOR FULL-LOAD: The torque developed by an electric motor (A.C. or D.C.) to produce its rated horsepower at rated full-load speed.
TORQUE, MOTOR PULL-UP: The minimum torque developed by a squirrel-cage or wound-rotor (slipring) motor during the period of acceleration from rest to the speed at which breakdown torque occurs. For squirrel-cage motors with 8% or greater slip, the pull-up torque, the break down torque, and the starting torque are all equal and occur at zero speed.
UPPER BLOCK: A fixed block located on a trolley that, through a system of sheaves, bearings, pins, and frame, supports the load block and its load.
WEB PLATE: The vertical plate(s) connecting the upper and lower flanges or cover plates of a girder.
CRANE ELECTRICS
ADJUSTABLE FREQUENCY DRIVE: A motor controller designed to convert fixed frequency AC power to available frequency power for AC motor speed control. The system is used in conjunction with a squirrel cage motor to control speed over a relatively wide, constant torque range, by maintaining a constant voltage / frequency ratio. This type of control “leashes” the in-rush current to deliver startup power to the motor as efficiently as possible providing a soft-start feature thereby minimizing load swing.
ANTI-COLLISION: An electrical means of keeping two (2) or more crane’s from contacting each other.
AUTOMATIC CRANE: A crane that automatically operates through a preset cycle or cycles.
COLLECTORS, CURRENT: Contacting devices for collecting current from runway or bridge conductors.
CONDUCTORS, BRIDGE: The electrical conductors located along the bridge structure of a crane that transmit control signals and power to the trolley(s).
CONDUCTORS, RUNWAY (MAIN): The electrical conductors located along a crane runway that transmit control signals and power to the crane.
CONTROLLER: A device or group of devices that serves to govern, in a predetermined manner, the power delivered directly to the apparatus to which it is connected.
CONTROLLER, MANUAL: A controller having all of its basic functions performed by devices that are operated by hand.
CONTROLLER, SPRING RETURN: A controller that, when released, will return automatically to a neutral (off) position.
CONTROL PANEL: An assembly of components (magnetic, static, hydraulic, pneumatic, etc.) that governs the flow of power to or from a motor or other equipment in response to signals from a master switch, push-button station, remote control, automatic program, or other similar device.
CONTROL PENDANT: A device that gives an operator precise control over the motions of the crane.
COUNTERTORQUE: A method of control by which the power to the motor is reversed to develop torque in the opposite direction to the rotation of the motor.
CREEP SPEED: A very slow, constant, continuous, fixed rate of motion of the hoist, trolley, or bridge: usually established at 1% to 10% of the normal full load speed.
DYNAMIC BRAKING: A method of controlling speed by using the motor as a generator, with the energy being dissipated in resistors.
ELECTRIFICATION SYSTEM: The various parts of the crane structure that supply and apply electricity to the trolley hoist.
EMERGENCY STOP (E-STOP): A manually or automatically operated electric switch to cut off electric power independently of the regular operating controls.
ENCLOSURES: The enclosures house all the electrical components on the crane.
FAIL-SAFE: A provision designed to automatically stop or safely control any motion in which a malfunction occurs.
FESTOON: A method for providing power to a hoist traveling along a beam.
JOG (INCH): To move the hook, trolley, or bridge in a series of short, discontinuous, increments by momentary operation of a controller.
LIMIT DEVICE: A device that is operated by some part or motion of a power-driven hoist, trolley, or bridge to limit motion.
LIMIT SWITCH: An electrical device which is operated by the bridge, trolley, or hoist motion to disconnect the circuit, to establish a new circuit, or to provide a warning.
LOAD FLOAT: A control system which enables Stepless operation of a hoist in either the lifting or lowering direction for a range of about 04% of full rated speed, as well as permitting the load to be suspended stationary for a very short time with the holding brake(s) released.
MAGNET: An electromagnetic device carried on a crane hook to pick up loads magnetically
MASTER SWITCH: A manually operated device which governs the operation of contactors and/or auxiliary devices of an electric control.
PENDANT STATION: Controls suspended from the crane for operating the unit from the floor.
PLUG: To operate a controller in such a manner that the motor line voltage polarity or phase sequence is reversed before the motor rotation has stopped, thereby developing a counter torque which acts as a retarding force.
PLUGGING RELAY: A current relay used on a bridge or trolley control panel which senses current in the motor secondary circuit of an alternating current motor and limits reverse torque of the motor to the first control point until the motor rotation has stopped. In a direct current control panel, the relay performs the same function by establishing a patented
POWER SUPPLY: The electrical service available in the building for which the crane is being designed.
RADIO REMOTE CONTROL: The radio control performs exactly like the pendant but operates using a radio frequency.
RUNWAY CONDUCTORS: The main conductors mounted on or parallel to the runway which provide electrical current to the crane.
SECONDARY VOLTAGE: The induced open-circuit voltage in the rotor of a wound-rotor (slipring) motor at standstill, as measured across the slip rings with rated voltage applied to the primary (stator) winding.
SWITCH, EMERGENCY STOP: A manually actuated switch to disconnect power independently of the regular operating controls.
SWITCH, LIMIT: A device that is actuated by the motion of a part of a power-driven machine or equipment to alter or disconnect the electric, hydraulic, or pneumatic circuit associated with the machine or equipment. switch, main (crane disconnect): a switch on the crane controlling the main power supply from the runway conductors.
SWITCH, MASTER: A switch that dominates the operation of contactors, relays, or other remotely operated devices.
SWITCH, MASTER, SPRING-RETURN: A master switch that, when released, will return automatically to a neutral (off) position.
SWITCH, RUNWAY DISCONNECT: A switch, usually at floor level, controlling the main power supply to the runway conductors.
SWITCH, VALVE: A device for making, breaking, or changing the connections in an electric, hydraulic, or pneumatic circuit.
VARIABLE FREQUENCY DRIVE (VFD): A device used in conjunction with a pendant to vary the frequency of the motors controlling the motions allowing for smooth acceleration and deceleration.
CRANE LAYOUT
BAY: The space between the building frames measured parallel to the crest of the building.
BRIDGE: The part of a crane consisting of one or more girders, trucks, end ties, foot walks, and drive mechanism, which carries the trolley or trolleys.
BRIDGE GIRDER(S): The primary horizontal beam of the crane bridge which supports the trolley and is supported by the end trucks.
BRIDGE TRAVEL: The crane movement in a direction parallel to the crane runway.
BUILDING AISLE: A space defined by the length of a building and the space between building columns.
CANTILEVER GANTRY CRANE: A gantry or semi-gantry crane where the bridge extends beyond the crane runway on one or both sides.
CAPACITY: The maximum weight in tons the crane will be required to lift.
CLEARANCE: The minimum distance from any part of the crane to the point of nearest obstruction.
CONDUCTORS, RUNWAY (MAIN): The electrical conductors located along a crane runway that transmit control signals and power to the crane.
CRANE: A machine for lifting and lowering a load and moving it horizontally, with the hoisting: mechanism being an integral part of the machine.
FLOOR-OPERATED CRANE: A crane which is controlled by an operator using a pendant station which is suspended from the crane.
FOOTWALK: A walkway with handrail and toe boards, attached to the bridge or trolley for access purposes.
GANTRY CRANES: An overhead crane where the bridge girder(s) are connected to “legs” on either side of the span. These “legs” eliminate the supporting runway and column system and connect to end trucks which run on a rail either embedded in, or laid on top of, the floor.
GANTRY LEG: The structural member that supports a bridge girder or end tie from the sill.
HEIGHT UNDER BOOM (HUB): The distance from the floor to the underside of a jib crane's boom. The minimum height under boom equals the height of the load, plus the maximum distance the load is to be lifted, plus the headroom required for the hoist, trolley, and attachments.
GIRDER, BRIDGE: The principal horizontal beam(s) of the crane, which supports the trolley, is supported by the end trucks, and is perpendicular to the runway.
GIRDER, RUNWAY: A horizontal beam attached to the building columns
HOIST: A machinery unit that is used for lifting or lowering a load.
HOIST, AUXILIARY: A supplemental hoisting unit, usually designed to handle lighter loads at a higher speed than the main hoist.
HOIST MOTION: Motion that lifts or lowers a load.
HOIST, MAIN: The primary hoist mechanism provided for lifting and lowering the rated load of the crane.
HOOK APPROACH, END: The minimum horizontal distance, parallel to the runway, between the centerline of the hook and the face of the wall (or columns) at the end of the building.
HOOK HEIGHT: See Lift Height.
HOOK APPROACH, SIDE: The minimum horizontal distance, perpendicular to the runway, between the centerline of a hook (main or auxiliary) and the centerline of the runway rail.
LIFT (HOOK TRAVEL): The maximum vertical distance through which the hook can move, as determined by the length of rope and/or the number of grooves on the drum. The lift height is the maximum vertical distance from the floor that the hook
LOAD: The total superimposed weight on the load block or hook.
POWER SUPPLY: The electrical service available in the building for which the crane is being designed.
RUNWAY: An assembly of rails, beams, girders, brackets, and framework on which the crane travels.
RUNWAY CONDUCTORS: The main conductors mounted on or parallel to the runway which provide electrical current to the crane.
RUNWAY RAIL: The rail supported by the runway beams on which the bridge travels.
SEMI-GANTRY CRANE: A gantry crane with one end of the bridge rigidly supported on one or more legs that run on a fixed rail or runway, the other end of the bridge being supported by a truck running on an elevated rail or runway.
SERVICE PLATFORM: A means provided for workers to perform maintenance, inspections, adjustments, and repairs of cranes.
SIDE PULL: The portion of the hoist pull acting horizontally when the hoist lines are not operated vertically.
SINGLE GIRDER: An overhead crane consisting of two end trucks, a single bridge girder and the trolley hoist unit. The trolley runs on the bottom flange of the bridge girder.
SPAN: The horizontal distance, center to center, between runway rails.
STANDBY CRANE: A crane which is not in regular service but is used occasionally or intermittently as required.
STOP: A device to limit travel of a trolley or crane bridge. This device normally is attached to a fixed structure and normally does not have energy-absorbing ability.
SUPPORT COLUMN: A separate column which supports the runway beam of a top running crane.
SUSPENSION SYSTEM: The system (rigid or flexible) used to suspend the runway beams of under hung or monorail cranes from the rafter of the building frames.
CHAIN
CHAIN GUIDE: A means to guide the hoist load chain at the load sprocket.
CHAIN HOIST: A hoist used for lower capacity, lighter duty applications and for projects in which cost is a primary deciding factor.
HAND CHAIN: The chain grasped by a person to apply force required for the lifting or lowering motion of the hoist.
HAND CHAIN WHEEL: A wheel with formed pockets on its periphery to allow torque to be transmitted when a force is applied to the hoist hand chain.
HAND GEARED: The operation of the bridge, hoist, or trolley of a crane by the manual use of chain and gear without electric power.
LOAD CHAIN: The chain used for the lifting or lowering motion of the live load.
LOAD SPROCKET: A hoist component that transmits motion to the load chain. This hoist component is sometimes called load wheel, load sheave, pocket wheel, or chain wheel.
LOAD SUSPENSION PARTS: The load suspension parts of the hoist are the means of suspension (hook or lug), the structure or housing which supports the drum or load sprocket, the drum or load sprocket, the rope or load chain, the sheaves or sprockets, and the load block or hook.
MANUALLY OPERATED CRANE: A crane whose hoist or travelling movements are manually controlled, for example by pulling the endless chain.
OVER-TRAVEL RESTRAINT: A device used to prevent the hoists slack load chain from inadvertently being lowered out of the load sprocket.
WELDED LINK CHAIN: A hoist chain consisting of a series of interwoven links formed and welded.