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Overhead Crane Terminology

Overhead Crane Terminology

December 22, 2023
Terminology OF Overhead Crane


 
  1. EOT Crane : Electric Overhead Travelling Crane
  2. Capacity : the rated capacity or the max load which this crane can handle or is designed to handle
  3. Height of lift : the distance of upper most to lowermost position which the crane can travel
  4. Building span : the center to center of building columns
  5. Crane span : the center to center distance of crane runway rails
  6. Headroom : distance between the topmost part of the crane to the hook saddle when the hook is at the topmost position
  7. Overhead clearance : distance between Gantry rail top to the building roof lowermost position
  8. Bay length : building length perpendicular to the crane bridge (also known as travel length)
  9. End approaches : the distance from end of the bay length to the center of the hook when the crane is at either extreme end.
  10. Hook approaches : The minimum distance between center of runway rail and hook (along the Bridge) when the trolley is at extreme end.
  11. End clearance : the minimum  distance from center of runway rail to side obstruction of the building
  12. Hook travel length : the maximum possible distance which hook can travel long the span of the crane
  13. MH : Main Hoisting motion
  14. AH : Auxiliary Hoisting motion
  15. LT motion : Long Travel Motion
  16. CT motion : Cross Travel Motion
  17. Bridge : the structural portion on which the trolley/crab moves
  18. LT End carriage : Structure which houses Long Travel Wheels
  19. CT End carriage : Structure which houses Cross Travel Wheels


 
  1. Crab : complete hoisting with cross travel arrangement having CT End carriages,  Ct Wheels, Ct Drive Mechanism, Hoisting gearboxes, motor, Equalizing, Wire rope drum etc.
  2. Base frame : Structural frame on which Gearbox, motor and brakes are mounted
  3. LT wheel Base : Distance between center of extreme LT wheels along the runway rail.
  4. LT wheel gauge : also equals to span - distance between center of LT wheels along bridge girder
  5. Ct Wheel Base :  Distance between center of extreme CT wheels along the runway rail.
  6. CT Wheel Gauge : Distance between center to center of CT Rails.
  7. Upper block/Equalizing : structural member comprising of Sheaves (pulleys) installed near the wire rope drum
  8. Lower block/ Hook Block/ Bottom Block  : structural member comprising of Sheaves (pulleys) and Hook through which wire ropes are routed
  9. L-block type wheel block : mechanism of fitting wheels to end carriages
  10. Live axles : where the axles also rotates along with the wheels
  11. Dead axles : where the axles remains stationary but the wheel rotates
  12. Shrink fitted wheels : The wheels are fitted onto the axles by shrink fitting procedure i.e. the wheels are heated to a  temperature which causes its bore to expand, the axles are inserted in the wheels, and the assembly is allowed to cool. As the wheel cools down the bore size shrinks and hence axles is fitted onto the wheels. By this mechanism the KEY way in the wheels are avoided.
  13. Driving wheels : the Set of Wheels on which the Gearbox is mounted and driving the wheels
  14. Idle Wheels : the set of wheels which do not have gearbox on it. They are the driven wheels
  15. Drive girder : The girder which has LT Driving Wheels, usually also has the main panel mounted on it, along with a platform
  16. 8 wheel configuration : normally there are total 4 nos of LT wheels. However when the crane capacity increases the no of LT wheels needs to be increased. For 8 nos of total LT Wheels is named as 8 wheel configuration
  17. Reeving : The path Wire rope follows going from wire rope drum to hook block and upper block is known as reeving arrangement and is more accurately depicted by no of leads / no of falls
  18. No of leads : the no of exit points of wire rope on a Drum
  19. No of falls : the physical no of rope lengths counted between the wire rope drum and the hook block
  20. Hook center to center : horizontal distance between centers of main and auxiliary hooks
  21. Maintenance cage/Cabin : a cabin for maintenance of DSL & current collectors
  22. Operators cage/cabin : a cabin having controls used for operation of the crane
  23. Radio remote : a device which operates the crane on radio frequency
  24. Pendant push button station : A crane controller usually wired
  25. Trailing Pendant : Pendant which can travel along the span of the crane independent of the crab
  26. CT DSL : power and control supply mechanism along the span of the crane to provide connection between main panel and crab
  27. LT DSL : Power supply mechanism along the bay length of the crane to provide power to the crane
  28. Current collector : device to collect power from live DSL
  29. Festooning :  a DSL systems where in cables are used along the span of the crane, to provide power and controls from panel to the crab and vice versa. The cables usually form loops.
  30. Energy chain : a DSL system as above, which provides power and control from panel to crab, but cables are housed in a chain
  31. Anti collision device : A device which detects another crane on the same bay,
  32. Tandem Motion : when 2 or more cranes are working simultaneously in synchronization
  33. Degree of protection of panel : ingress protection of panel
  34. S4 duty motors : intermittent periodic duty with starting motors , specially for crane application
  35. Deflection : the vertical downward movement of girder when crab being at center of crane lifts rated load.
  36. Camber : slight upward curved of the girder, usually equal to the deflection at rated load
  37. End stop : the physical stopping members installed at the ends of RAILS which prevents crane from overtravel in case of limit switch failures
  38. Runway rails : Rails along the bay length of the building on which LT wheels runs
  39. Storm brake : Special additional brakes which locks the crane to a fixed member, used when crane is working outdoors and in stormy conditions
  40. Fail safe brake : Brake which will apply when the power is lost. In cranes and hoists all brakes used are fail safe brakes.
  41. Under bridge lights : lights mounted below the crane girder
  42. Wheel load : load on the wheel which will be passed on the respective supporting structure below it
  43. Gantry girder / runway girder : Girders along the bay length, on which the runways rails will be installed
  44. Gravity limit switch : additional upper limit switch which is installed to prevent accident of hook block and the crab in case the upper limit fails to activate
  45. Flame proof cranes : Cranes which works in hazardous environments
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