Jib Crane Bearings

[boze]

Client wants to build his own 1 ton 360 degree swing jib crane.
Have a number of books and references, but still have questions regarding bearing selection design.

Top bearing - probably spherical and thrust bearing.
Lower bearing - thought of several Gill roller bearings for the knee brace/ moment calculation.

System will be outdoors, and used infrequently - several times a year at most.

With crane in a static condition most of the year, can be tough on bearings, so will oversize bearings.

Am not satisfied at this point, so would appreciate a source that could address typical bearing design methods.

 

[unclesyd]

Have you looked at sleeve bearings since you have infrequent use and a relative light load. I would also look at some of the composite sleeve bearings.

 

[GregLocock]

Yup, plain bearings and lots of grease

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[CESSNA1]

BOZE: Before going any further, I suggest you consider the liability issue. There are plenty of designed and proven cranes available. Why does the client want one custom designed? I would stay away from this unless you have much prior crane design experience.

Regards
Dave

 

[IceStationZebra]

I agree with Greg - plain bearings would be the best choice. You didn't indicate how long the arm would be, but 1t shouldn't be a big deal. You can easily use a brass sleeve/block with a steel pin for the top pivot. The bottom bearings could either be brass wheels on steel pins or off the shelf bearings. Just make sure you have enough of a gap to get some grease in between the parts.

ISZ

 

[MikeHalloran]

You normally slew the jib by tugging on the hoist chain. The users will curse you for using plain bearings and making their job that much harder. No one will grease them, ever.

Jib cranes are available pre- engineered in any reasonable size. Doing one from scratch is crazy. You still need to engineer a very heavy foundation; that should be challenge enough.











Mike Halloran
Pembroke Pines, FL, USA

 

[safetydan]

Cessna1 is absolutely correct. You will need to either engineer the heck out this crane, or you will be facing HUGE liability issues. Considering this crane is going to be outdoors and used infrequently you are setting yourself up for a disaster. The first year of use won't have much effect on the crane, but after year 2, 3, and 4 you will start to run into issues. Corrosion on the crane, supports, bearings, hook, and other components will take their toll and weaken the crane significantly. I would highly reccomend you get away from this project in a hurry. Remember, it's your name and license on the line.

 

[Simmers]

there are inexpesive, pre-engineered supports for jibs

Go to

http://www.gorbel.com

or

http://www.spanco.com

 

[boze]

Thanks to all.

Liability concerns are always a first consideration.