OK, this should be an easy one, but the acronym finders didn’t give me a hit on this, probably because it’s a Britishism. I was looking thru the Scrapheap Challenge (Junkyard Wars) website, and ran across this chat snippet.
So what’s a JCB??
It is a fairly classic agricultural or construction vehicle - well, range of vehicles really. I think of them as always being black and yellow in colour, but that may be wrong. http://www.jcb.co.uk/Home/main_index.asp
Danke. Didn’t even occur to me that it would be initials for a specific brand of equipment. I just figured it had to stand for some obscure combination of words that only the English could come up with. Oh well 
Celyn’s spot on. In pop culture references JCB usually means any violently yellow oversized big-wheeled construction vehicles.
Lookee here
http://www.wyburns.com/pond/jcb1_large.htm
They operate in the US too so I thought you might like this
http://www.jcbna.com/index.htm
There is a strange bunch of people who are JCB afficionados collecting JCB models kits and the like.
They get noticed by us Brits because they are often the cause of slow moving traffic, they do about 20mph.This is a familiar sight for UK motorists.
http://www.freefoto.com/pictures/transport_land/roadwork/index.asp?i=8
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Actually you might like that last link, if you go to pictures of England and then on to Yorkshire and then last on to pictures of Whitby you’ll see photo’s of Whitby Abbey, St Hilda’s church and the harbour piers.
These are all mentioned in Bram Stokers original Count Dracula book . I reckon it would be a cool place to take EvilBear if the tour ever gets off the ground.
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And this is the mother of all JCB sites.
Go to the UK section, check out the merchandising, some folk will choose nothing else, I particularly like the JCB excavator golf wedges. Can’t imagine that they would be too popular with the course stewards at the Belfry.
Kewl! Here’s the North American JCB page from Casdave’s link. http://www.jcbna.com/products/products_index.htm
In the U.S., we would refer to these not collectively as “JCBs” but by their individual names, “backhoe”, “forklift”, etc. The one that says “wheel loader” I would probably call a “front loader”.