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sheave, nonrunning - upper block

sheave, nonrunning (equalizer): this sheave equalizes tension in the opposite part of the rope. it is not concidered a running sheave due to its slight movement.

switch, master, spring-return: when released, this master switch will automatically return to an off, or neutral, position.

truck:, supporting the sill of a gantry crane, the bridge girders, or the end ties of an overhead crane,  this unit consists of wheels, a frame, axles, and bearings.

switch, emergency stop: used to disconnect power without needing the regular operating controls, this is a manually actuated switch.

sills: connecting the lower ends of two or more legs of a gantry crane on one runway, these structural members are horizontal.

span: center to center, this is the horizontal distance between runway rails.

trolley: supporting the load block, this unit travels on the bridge rails.

should: the given rule is a recommendation when this word is used, whether or not it is followed is dependent on the moment.

switch, main (crane disconnect): the main power supply is controlled by this crane switch from the runway conductors.

side pull: when the hoist lines are not operated vertically, this part of the hoist pull acts horizontally.

trolley travel: movement of the trolley

switch (valve): this device is used for breaking, changing or making the connections in a hydraulic, pneumatic, or electric circuit.

switch, runway disconnect: normally at ground level, this switch controls the main power supply to the runway conductors.

switch, limit: actuated by the motion of a part of a power-driven equipment or machine, this device is used to disconnect or alter the hydraulic, pneumatic, or electric circuit affiliated with the equipment or machine.

unattended: the operating control devices are not manned by the operator of the crane in this condition. However, if the control devices used for operating are within sight of the operator on a floor-operated crane, and within an equal distance to crane’s span, the crane should be thought as attended.

sheave, running: as the load block is lowered or lifted, this sheave rotates.

slash (/): this indicates that two words are to be taken individually or together and denotes “and/or”.

stop: used for limiting travel of a crane bridge or trolley, this device does not usually have energy-absorbing ability and is attached usually to a fixed structure.

switch, master: the operation of relays, contactors, or other devices that are operated remotely is controlled by this switch.

upper block: through a system of frame, bearings, sheaves, and pins,  this fixed block, located on a trolley, supports its load and the load block.