Technical bases
Load factors for bearing selection
Except for Standard series KD 210, types 13 and 21.
| Application | fstat | fL | Service Time in Full Load Revolutions |
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| Floating Crane (Cargo) Mobile Crane (Cargo) Ship Deck Crane (Grab) Welding Positioner Turntable (Permanent Rotation) |
1.10 | 1.00 | 30,000 | ||
| Tower Crane |
Bearing at top |
Mkrü ≤ 0.5 Mk | 1.25 | 1.00 | 30,000 |
| 0.5 Mk ≤ Mkrü ≤ 0.8 Mk | 1.15 | 45,000 | |||
| Mkrü ≥ 0.8 Mk | 1.25 | 60,000 | |||
| Bearing at base | 1.00 | 30,000 | |||
| Slewing Crane (Cargo) Shipyard Crane Rotatable Trolley (Cargo) Shiploader / Ship unloader |
1.15 | 45,000 | |||
| Steel Mill Crane | 1.45 | 1.50 | 100,000 | ||
| Mobile Crane (Grab or heavy handling service) Slewing Crane (Grab/Magnet) Rotatable Trolley (Grab/Magnet) Bridge Crane (Grab/Magnet) Floating Crane (Grab/Magnet) |
1.70 | 150,000 | |||
| Main slewing gear of Bucket Wheel Excavator Reclaimer Stacker Boom Conveyor |
2.15 | 300,000 | |||
| Offshore Crane | subject to special criteria | ||||
| Railway Crane | 1.10 | For these applications please mind the accompanying note. | |||
| Deck Crane (Cargo) | 1.00 | ||||
| Stacker Boom Conveyor Conveyor Waggon |
1.10 | ||||
| Cable Excavator/Dragline Swing Shovel |
1.25 | ||||
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Hydraulic Excavator Bearing from KD 320 Series Other bearing types Hydraulic Excavator up to 1.5m³ |
1.25 1.45 |
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| exceeding 1.5m³ | subject to special criteria | ||||
| Ladle Car | 1.75 | ||||
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Static rating principally requires taking into account the maximum occurring loads which must include additional loads and test loads. Static safety factors (fstat e.g. for erection loads, higher test loads etc.) must not be reduced without prior written approval from us for exceptional cases. |
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| The fL values shown refer to a rating for max. operating load and have been obtained from operating experience and tests. If a load spectrum with an assumed average load is used to obtain the required full load revolutions, the service time values must be increased accordingly. |
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Tower Cranes with bearing at top: Mkrü = restoring moment without load Mk = Moment at max. radius with load |
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| For applications requiring a rating of fstat = 1.45, multi-row designs should be given preference because of the high average loads and arduous operating conditions. |
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Note: In these applications, the operating conditions, particularly the operating time and the loads during the slewing process, vary considerably. Infrequent slewing motions, e.g. occasional positioning for certain jobs, may permit a rating on static criteria alone. On the other hand, continuous rotation or oscillating motions will require a rating on the basis of service time criteria. Selections based on service time may also be required if the bearing carries out relative movements, which is often the case with the discharge boom conveyors in bucket wheel units. |
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