Overhead Crane Terminology

Know about the 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
20. Crab : complete hoisting with cross travel arrangement having CT End carriages, Ct Wheels, Ct Drive Mechanism, Hoisting gearboxes, motor, Equalising, Wire rope drum etc.
21. Base frame : Structural frame on which Gearbox, motor and brakes are mounted
22. LT wheel Base : Distance between center of extreme LT wheels along the runway rail.
23. LT wheel gauge : also equals to span – distance between center of LT wheels along bridge girder
24. Ct Wheel Base : Distance between center of extreme CT wheels along the runway rail.
25. CT Wheel Gauge : Distance between center to center of CT Rails.
26. Upper block/Equalising : structural member comprising of Sheaves (pulleys) installed near the wire rope drum
27. Lower block/ Hook Block/ Bottom Block : structural member comprising of Sheaves (pulleys) and Hook through which wire ropes are routed
28. L block type wheel block : mechanism of fitting wheels to end carriages
29. Live axles : where the axles also rotates along with the wheels
30. Dead axles : where the axles remains stationary but the wheel rotates
31. 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.
32. Driving wheels : the Set of Wheels on which the Gearbox is mounted and driving the wheels
33. Idle Wheels : the set of wheels which do not have gearbox on it. They are the driven wheels
34. Drive girder : The girder which has LT Driving Wheels, usually also has the main panel mounted on it, along with a platform
35. 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
36. 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
37. No of leads : the no of exit points of wire rope on a Drum
38. No of falls : the physical no of rope lengths counted between the wire rope drum and the hook block
39. Hook center to center : horizontal distance between centers of main and auxiliary hooks
40. Maintenance cage/Cabin : a cabin for maintenance of DSL & current collectors
41. Operators cage/cabin : a cabin having controls used for operation of the crane
42. Radio remote : a device which operates the crane on radio frequency
43. Pendant push button station : A crane controller usually wired
44. Trailing Pendant : Pendant which can travel along the span of the crane independent of the crab
45. CT DSL : power and control supply mechanism along the span of the crane to provide connection between main panel and crab
46. LT DSL : Power supply mechanism along the bay length of the crane to provide power to the crane
47. Current collector : device to collect power from live DSL
48. 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.
49. Energy chain : a DSL system as above, which provides power and control from panel to crab, but cables are housed in a chain
50. Anti collision device : A device which detects another crane on the same bay,
51. Tandem Motion : when 2 or more cranes are working simultaneously in synchronization
52. Degree of protection of panel : ingress protection of panel
53. S4 duty motors : intermittent periodic duty with starting motors , specially for crane application
54. Deflection : the vertical downward movement of girder when crab being at center of crane lifts rated load.
55. Camber : slight upward curved of the girder, usually equal to the deflection at rated load
56. End stop : the physical stopping members installed at the ends of RAILS which prevents crane from over travel in case of limit switch failures
57. Runway rails : Rails along the bay length of the building on which LT wheels runs
58. Storm brake : Special additional brakes which locks the crane to a fixed member, used when crane is working outdoors and in stormy conditions
59. Fail safe brake : Brake which will apply when the power is lost. In cranes and hoists all brakes used are fail safe brakes.
60. Underbridge lights : lights mounted below the crane girder
61. Wheel load : load on the wheel which will be passed on the respective supporting structure below it
62. Gantry girder / runway girder : Girders along the bay length, on which the runways rails will be installed
63. 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
64. Flame proof cranes : Cranes which works in hazardous environments

DG EOT CRANE  DRAWING