Jib crane question

For some reason, I cannot see the picture now but, the link works and shows very good images and information.

Ray

stevecmo said:
As Tony alluded to, and Ray's picture shows, one of the easiest thing to overlook on a jib crane is the base and anchoring system. It's easy to focus on the beam and pivot connection and overlook the base. The calculations get pretty complicated and are dependent on the thickness (and quality) of the floor slab.

Be careful.

Steve
Click to expand...
 
Concur typical garage floor slab will not have rebar= break floor pour reinforced pier use j-bolts to anchor. top stay of jib has very acute angle, back stays are making a lot of space useless and could have a more acute angle, gusset base plate gusset jib boom at column, gusset from above to below pivot point.

Consider rigging trolley beams next to lathe 2 perpendicular 1 parallel parallel beam to trolley inside the flanges of perpendicular beams for increased head space.

Bob
 
The formula for figuring the thickness of the jib arm is in the Machineries Handbook. I always refer to it if I am looking for a numeric solution because that is what that book excels at the best. I don't remember exactly where it is, but there have been discussions about this on other sites and the answer was found in the book. I too tend to over engineer my projects to insure complete safety when I use that kind of equipment. Coming from a rigging and wrecker back ground has given me a really healthy respect of that kind of work and the stresses involved. If a cable snaps or a block fails some one is going to get hurt, it never fails. So I plan for it and prevent the failure by exceeding the requirement every time. HTH.

Bob
 
When my dad built a new shop a few years ago he had me engineer a crane that was anchored to and built into one corner of the building itself. The corner vertical beam was a very beefy angle, with diagonal braces down to bolts in the slab, which was engineered to handle it. The main beam is a 10" deep I with 6" flanges, I believe 3/8" thick (would have to check). The bottom line is, Machinery's Handbook has easy to use formula for calculating a cantilever beam, which I used. Also double checked with some other beam formulas I was familiar with from engineering school, and it all told the same story. For reference, that 10" deep I beam was sized to handle a 700# engine out at it's full 10' extent, so it's a lot more load than you are talking. Just remember to apply a generous safety factor (I used 5 times the expected load).

Patrick
 
is there some reason you are wanting a jib crane and have you ruled out a portable aluminum gantry crane? for just the 200# at the end of a jib crane a lightweight adjustable gantry crane could handle that weight with ease, but would be able to lift a half ton also. we used portable adjustable gantry cranes at work and they were very handy. maybe you need a jib crane, but they are very expensive to put in a shop, compared to gantry cranes. just a thought Dave--:thinking:
 
I looked at a couple of gantry style cranes, I feel I might be going that route as the gantry will accomidate all 3 machines, and the door. Thank yall for all your help. Now if anybody has a few gantry designes I would love to see them!:whistle:
 
I agree that a gantry set up would be more flexible and capable of reaching more places in the shop. It is also capable of moving the load once you have it slung. just lower it as close to the floor as possible and move right along. we moved big ole detriot diesels in Iraq for Hemmts and tank haulers. The cab was a mere 23 tones and once we lifted it off we could access the engine and trans as a unit. we changed those engines very frequently due to oil leaks and supercharger run aways. Once it runs away the Army wants it replaced without question. So we replaced a lot of perfectly fine engines because of "Policy" what a waste of funding and resources. Oh well I just turned the wrenches I did not dictate policy or decide what was done to the vehicle. I just hated to see such a waste. Just the oils and chenicals were more than I would have imagined due to the cost of getting it into theatre. One gallon of 15-40 oil was valued at 35 dollars and a 1 liter bottle of water was billed at 3 dollars a bottle. Just my .02 worth though....

Bob
 
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