Gantry Crane_QA_20230410.pdf

Gantry Crane, Vandenberg Space Force Base Q & A

1. What should be the capacity of each hoist be? We understand the gantry will be rated at 5 Ton.

2.5 Ton

2. If chain hoist is provided, should it have a chain container?

Yes

3. What service rating for the hoists should be provided?

2.5 Ton

4. In the specifications you state “overall height of the crane at 17.5'. Is this to the bottom of the gantry beam? Typically, gantry cranes are specified by the height of the lower flange, not the top.

No. This is to the overall top of the Gantry. This is to accommodate the interior dimensions of our High Bay. We want to take full advantage of our space.

5. Will the trolley for each hoist be powered and will they require a Variable Frequency Drive? Trolley brakes?

Hoist trollies need not be powered. No breaks required.

6. You specified Variable Speed for the hoist, are we correct to assume this is a Variable Frequency

Drive or just a two-speed hoist motor?

Yes. Variable.

7. Will a flat cable festoon need to be provided for each hoist?

A good idea but not required. (Power cable for hoist should be long enough for either hoist to roll to opposite side of the gantry as disconnect while also being supported up and around the gantry.)

8. Will a single disconnect be required for the gantry or one for each hoist mounted on the gantry columns? We assume the government provides power cable to the disconnect switch(s).

Yes. Single is preferred.

9. Will rubber bumpers and drop lugs be required on the trolleys? Any limit switches to prevent the trolley from running into the end stop and or the other trolley?

Tollies should not be able to roll of the I-Beam once assembled. Beyond that. No requirement.

10. Will the gantry crane need turning wheel locks and brakes (manual type)?

Manual Non caster with wheel lock. Gantry should roll perpendicular to the motion of the trollies.

11. Will the gantry crane be used on a flat surface?

Yes. Level shop floor.

12. Will the hoists need to have true vertical lift? Zero hook movement laterally from up to down?

No. However, the expectation is that cable or chain will spool gracefully and not jump position suddenly while under load, i.e. causing unexcepted jerks or motion.

13. Should the pendant controls for each hoist be mounted to the trolley hoists?

Yes. Hanging to a natural height for control from the ground.